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TABLE OF CONTENTS
INDEX TO FINANCIAL STATEMENTS

As filed with the Securities and Exchange Commission on June 15, 2004.

Registration No. 333-113522



UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549


Amendment No. 4
to
FORM S-1
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

MOMENTA PHARMACEUTICALS, INC.
(Exact name of registrant as specified in its charter)


Delaware
(State or other jurisdiction of
incorporation or organization)
  2836
(Primary Standard Industrial
Classification Code Number)
  04-3561634
(I.R.S. Employer
Identification Number)

43 Moulton Street
Cambridge, MA 02138
(617) 491-9700
(Address, including zip code, and telephone number, including area code,
of registrant's principal executive offices)


Alan L. Crane
Chairman of the Board, President and Chief Executive Officer
Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138
(617) 491-9700
(Name, address, including zip code, and telephone
number, including area code, of agent for service)




Copies to:
Steven D. Singer, Esq.
Philip P. Rossetti, Esq.
Wilmer Cutler Pickering Hale and Dorr LLP
60 State Street
Boston, Massachusetts 02109
(617) 526-6000
  Jonathan L. Kravetz, Esq.
Darin P. Smith, Esq.
Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
One Financial Center
Boston, Massachusetts 02111
(617) 542-6000

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date hereof.

        If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act, check the following box.     o

        If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.     o

        If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration number of the earlier effective registration statement for the same offering.     o

        If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration number of the earlier effective registration statement for the same offering.     o

        If delivery of the Prospectus is expected to be made pursuant to Rule 434, please check the following box.     o


         The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.




The information in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to completion, dated June 15, 2004

5,350,000 Shares

MOMENTA

Common Stock


        Momenta Pharmaceuticals, Inc. is offering 5,350,000 shares of common stock. This is our initial public offering, and no public market currently exists for our shares. We anticipate that the initial public offering price will be between $13.00 and $15.00 per share. After the offering, the market price for our shares may be outside this range.


        We have applied to have our common stock approved for quotation on the NASDAQ National Market under the symbol "MNTA."


         Investing in our common stock involves a high degree of risk. See "Risk Factors" beginning on page 7.


 
  Per Share
  Total

Offering price   $                   $                

Discounts and commissions to underwriters   $                   $                

Offering proceeds to Momenta Pharmaceuticals, Inc. before expenses   $                   $                

        We have granted the underwriters the right to purchase up to 802,500 additional shares of common stock to cover any over-allotments. The underwriters can exercise this right at any time within 30 days after the offering. The underwriters expect to deliver the shares of common stock to investors on or about                , 2004.

        Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved these securities or determined if this prospectus is accurate or complete. Any representation to the contrary is a criminal offense.


SG Cowen & Co.

 

Banc of America Securities LLC



CIBC World Markets

 

ThinkEquity Partners LLC

                     , 2004



TABLE OF CONTENTS

 
  Page
Summary   1
Risk Factors   7
Special Note Regarding Forward-Looking Information   27
Notices to Investors   27
Use of Proceeds   28
Dividend Policy   28
Capitalization   29
Dilution   31
Selected Financial and Operating Data   33
Management's Discussion and Analysis of Financial Condition and Results of Operations   34
Business   44
Management   77
Certain Relationships and Related Party Transactions   92
Principal Stockholders   97
Description of Capital Stock   101
Shares Eligible for Future Sale   104
Underwriting   106
Legal Matters   110
Experts   110
Where You Can Find More Information   110
Index to Financial Statements   F-1



SUMMARY

         This summary highlights information contained elsewhere in this prospectus that we believe is most important to understanding how our business is currently being conducted. You should read the entire prospectus carefully, including the "Risk Factors" section and the financial statements and related notes included in this prospectus, before making an investment decision.

Overview

        Momenta is a biotechnology company specializing in the detailed structural analysis and design of complex sugars for the development of improved versions of existing drugs, the development of novel drugs and the discovery of new biological processes. We are also utilizing our ability to sequence, or analyze the molecular structure of, sugars, to create generic versions of complex sugar-based drugs, or technology-enabled generic products. Through detailed analysis of the molecular structure of complex sugars, our technology provides a more complete understanding of the roles that sugars play in cellular function, disease and drug action. Based on our understanding of complex sugars, we have developed a diversified pipeline of novel discovery and development candidates and near-term product opportunities.

        Our most advanced product candidate, M-Enoxaparin, is designed to be a technology-enabled generic version of Lovenox® (enoxaparin), a low molecular weight heparin, or LMWH, used to prevent and treat deep vein thrombosis, or DVT, and treat acute coronary syndromes, or ACS. Aventis SA, or Aventis, reported worldwide sales of Lovenox of approximately $1.9 billion in 2003, and analysts project sales to exceed $3.0 billion in 2008. We expect to file an Abbreviated New Drug Application, or ANDA, or other regulatory application as determined by the United States Food and Drug Administration, or FDA, for M-Enoxaparin in the next 12 months. In addition, we intend to develop a technology-enabled generic version of Fragmin® (dalteparin), another LMWH. Our novel development opportunities include: M118, which is a LMWH to treat patients with ACS that has been designed by selecting specific sugar sequences with beneficial biological activity; a technology designed to use specific sugar sequences to improve the non-invasive delivery of therapeutic proteins; and capabilities that are designed to enable engineering of complex sugars on therapeutic proteins to improve the efficacy, reduce side effects and modify the dosage of protein drugs. Our drug discovery program, which is focused initially in oncology, is based upon our understanding of sugar biology. We believe that we will be able to use this understanding to develop sugar-based drugs and identify new biological mechanisms that can be targeted with small molecule or antibody drugs.

Background on Sugars

        Sugars, together with DNA and proteins, are the critical molecules that regulate biological processes and pathways in the human body. Due to the complex molecular structures of sugars and the lack of sophisticated analytical tools and methods required to examine the minute quantities of sugars that occur in nature, sugars have not been well defined or analyzed. Without being able to identify specific structures, it is not presently possible to monitor how these sugars act in biological organisms. As a consequence, the development of sugar-based drugs to date has been through more of a "trial-and-error" approach. Because of the density of information contained in complex sugars relative to DNA and proteins and the lack of sophisticated tools to sequence such sugars, development of therapeutics based on sugars has been difficult. We believe understanding the structure, specific function and manner in which complex sugars affect critical biological processes and existing therapeutics will provide significant commercial opportunities for drug discovery and development.

1



Our Technology Solution

        Our technology enables rapid, precise and comprehensive sequencing and identification of the distinct chemical structures of a mixture, or characterization, of complex sugars and allows us to correlate specific sugar sequences with biological activity. With proprietary enzymes and reagents, improvements to established analytical techniques and patent-protected mathematical methods, our technology allows us to specifically identify the detailed sequences and the complete chemical structure of complex sugars, not simply the basic underlying backbone of the sugar chain. We intend to utilize our technology to develop generic versions of complex drugs, enhance existing therapeutics, engineer novel drugs and identify the roles sugars play in regulating biological processes to facilitate the discovery of new sugar-based, small molecule and antibody drugs, as well as the development of diagnostic tests to diagnose disease and determine disease severity.

Our Product Pipeline

Near-Term Product Opportunities

        M-Enoxaparin.     Our most advanced product candidate, M-Enoxaparin, is designed to be a technology-enabled generic version of Lovenox. Lovenox is distributed worldwide by Aventis, and is the most widely-prescribed LMWH in the world. In 2003, Aventis reported worldwide sales of Lovenox of approximately $1.9 billion. We have formed a collaboration with Sandoz N.V., and Sandoz Inc., collectively Sandoz, an affiliate of Novartis AG, to jointly develop, manufacture and commercialize a generic version of Lovenox. We intend to file our regulatory application with the FDA in the next 12 months for this product.

        Lovenox is a heterogeneous mixture of complex sugar chains that has not been adequately analyzed to date. Under FDA guidelines, any regulatory application for a generic product, such as a generic version of Lovenox, must demonstrate that it is therapeutically equivalent to the branded drug, meaning, among other things, that it has the same active ingredients as the branded version and is bioequivalent. Our ability to sequence and analyze complex sugar mixtures has allowed us to study the many sugar structures in Lovenox that contribute to its overall biological activity and develop a process for making a generic version of Lovenox we believe will meet the FDA requirements for an ANDA approval, including therapeutic equivalence. If we are not able to demonstrate therapeutic equivalence for our generic versions of complex drugs, such as LMWHs, our development and commercialization efforts for M-Enoxaparin and other complex drug candidates may be materially harmed.

        Aventis has listed two patents for Lovenox in the Orange Book, the FDA's listing of approved drug products. The FDA Orange Book lists drug products approved under the Federal Food, Drug and Cosmetic Act with therapeutic equivalence evaluations and is used by healthcare professionals to determine, among other things, their guidelines for substitution of generic versions of branded drug products.

        The Aventis patents listed in the Orange Book expire on December 24, 2004, which is prior to the date we anticipate we will commercialize M-Enoxaparin, and February 14, 2012, respectively. As is common with generic applications corresponding to branded drugs for which unexpired patents are listed in the Orange Book, we anticipate that Aventis will initiate patent infringement proceedings against Sandoz and us to prevent the marketing of M-Enoxaparin. These proceedings could be costly and time consuming, and ultimately delay or prevent the commercialization of M-Enoxaparin.

        M-Dalteparin.     We intend to develop a technology-enabled generic version of Fragmin, a LMWH marketed by Pfizer in the United States that is approved for the prevention of DVT and treatment of ACS. In 2002, Fragmin had worldwide sales of approximately $270 million. Our plan is to file a regulatory application for M-Dalteparin in the next 18 to 24 months. Pfizer has listed one patent for Fragmin in the Orange Book which expires January 4, 2005, prior to our plans for commercialization.

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Improved Development Products

        M118.     M118 is a LMWH that we specifically designed to provide improved efficacy and flexible administration as baseline therapy for treating patients with ACS. M118 is currently in preclinical development. We intend to file an investigational new drug application, or IND, prior to the end of the first half of 2005 and begin Phase I clinical trials shortly thereafter.

        Sugar-mediated non-invasive delivery.     We have identified a novel biological mechanism by which sugars facilitate the transport of molecules, including proteins, across mucosal membranes like those found in the lung. We believe our approach to pulmonary delivery of therapeutic proteins could result in significant advantages over current technologies, including an improved safety profile, higher levels of drug in the blood, or bioavailability, and delivery of larger therapeutic proteins. We are focusing our initial development on pulmonary formulations of several existing drugs, including interferon-beta, also known as Avonex® and Rebif®, erythropoietin, also known as Epogen® and Procrit®, insulin and human growth hormone, or HGH.

        Capabilities that enable engineering of complex sugars on therapeutic proteins.     Our analytical and sequencing technologies can also be applied to characterize and reengineer sugars that exist on therapeutic proteins. Altering the complex sugar coat of a protein can potentially improve efficacy and tissue targeting, reduce negative side effects and modify the dosing frequency of a protein drug.

Discovery Product Candidates

        Recent research has shown that sugars play a critical role in influencing signaling between proteins in pathways to fundamentally affect basic biology. We believe our technology can be utilized to understand the relationship between sugars and disease progression to advance the discovery of novel sugar-based small molecule and antibody drugs to treat a range of diseases, including cancer, cardiovascular disease and inflammatory disease. For example, we have identified specific sugar sequences that have demonstrated potent anti-cancer effects in animals, though early findings in animals do not always predict a response in humans.

Our Business Strategy

        Our objective is to become a leading biotechnology company by applying our understanding of complex sugars and our proprietary technologies to drug discovery, development and commercialization. The key elements of our strategy are to (i) maximize the commercial potential of M-Enoxaparin and leverage our analytic capabilities to commercialize other near-term opportunities, (ii) advance our improved development product opportunities into clinical trials, (iii) leverage our proprietary technology and apply our understanding of sugars to create novel therapeutics to address critical unmet needs, (iv) enhance our internal development programs through selective partnering, and (v) establish development capabilities and sales and marketing capabilities focused on key in-hospital markets.

Management Team

        We are led by a team of experienced biotechnology and pharmaceutical industry executives and recognized experts in glycobiology, or the study of complex sugars. We believe this team provides us with significant capabilities in the discovery, development and commercialization of therapeutics, resulting from our understanding of complex sugars. If we are unable to retain our management team or recruit additional executives, our business may suffer.

3



Early-Stage Company

        We have a limited operating history and have not yet commercialized any products. We have not been profitable in any quarter since inception. As of March 31, 2004, we had an accumulated deficit of approximately $39.4 million. We recognized net losses of $2.6 million for the first quarter of 2004, $7.9 million for the year ended December 31, 2003 and $4.9 million for the year ended December 31, 2002. We expect to incur substantial and increasing losses for the next several years as we develop our product candidates, expand our research and development activities and prepare for the commercial launch of our product candidates. We do not know when or whether we will become profitable. The majority of our products are in the early stages of development where failure is common and the technology we are using to discover and develop some of our drugs is novel and unproven. To be successful, we will need to conduct preclinical studies and clinical trials and obtain regulatory approval. Our drug candidates may encounter problems that could result in the lack of regulatory approval to market our products. In addition, several of our product candidates are generic versions of branded drugs for which unexpired patents may be listed in the Orange Book. We will be required to demonstrate therapeutic equivalence to a reference listed drug, and certify that any unexpired listed patent is invalid, unenforceable and/or not infringed prior to commercialization, and our ability to commercialize our product candidates will depend, in part, on our success in intellectual property litigation, if any.

Corporate Information

        We were incorporated in Delaware in May 2001 as Mimeon, Inc. In September 2002, we changed our name to Momenta Pharmaceuticals, Inc. Our principal executive offices are located at 43 Moulton Street, Cambridge, Massachusetts 02138. Our telephone number is (617) 491-9700. Our website address is www.momentapharma.com . The information on our website is not incorporated by reference into this prospectus and should not be considered to be a part of this prospectus. We have included our website address as an inactive technical reference only.


        Unless otherwise stated, all references to "us," "our," "Momenta," "we," the "Company" and similar designations refer to Momenta Pharmaceuticals, Inc. Our logo, trademarks and service marks are the property of Momenta. Other trademarks or service marks appearing in this prospectus are the property of their respective holders.

4


THE OFFERING


Common stock offered

 

5,350,000 shares

Common stock to be outstanding after this offering

 

24,563,183 shares

Use of proceeds

 

We intend to use the net proceeds to fund the approval and subsequent commercialization of near-term product candidates, development of improved product candidates, research and discovery of novel therapeutics and technologies and working capital, capital expenditures and other general corporate purposes. See "Use of Proceeds."

Proposed NASDAQ National Market symbol

 

MNTA

Risk factors

 

See "Risk Factors" and the other information included in this prospectus for a discussion of factors you should carefully consider before deciding to invest in shares of our common stock.

        The number of shares of our common stock to be outstanding after this offering is based on the number of shares outstanding as of April 30, 2004.

        The number of shares of our common stock to be outstanding after this offering does not take into account:



        Unless otherwise noted, the information in this prospectus assumes that the underwriters do not exercise their over-allotment option, reflects a 1.28-for-1 stock split of our common stock, which was effected on May 10, 2004, reflects the automatic conversion of all outstanding shares of our convertible preferred stock into an aggregate of 15,014,390 shares of common stock upon the completion of this offering and gives effect to the filing of our amended and restated certificate of incorporation and the adoption of our amended and restated by-laws upon the closing of this offering.

5



SUMMARY FINANCIAL AND OPERATING DATA

        The following table presents a summary of our historical financial information. You should read this information in conjunction with our financial statements and related notes and the information under "Selected Financial and Operating Data" and "Management's Discussion and Analysis of Financial Condition and Results of Operations," all included elsewhere in this prospectus.

        The pro forma net loss attributable to common stockholders per share information is computed using the weighted average number of common shares outstanding, after giving pro forma effect to the automatic conversion of all shares of our redeemable convertible preferred stock outstanding at March 31, 2004 into an aggregate of 15,014,390 shares of our common stock effective upon the completion of this offering, as if the conversion had occurred at the date of the original issuance. This pro forma information does not give effect to the issuance of common stock upon the exercise of the outstanding stock options or the outstanding warrant.

 
  Period from
Date of
Inception
(May 17, 2001)
through
December 31, 2001

   
   
   
   
 
 
  Year Ended
December 31,

  Three Months Ended
March 31,

 
 
  2002
  2003
  2003
  2004
 
 
   
   
   
  Unaudited

 
 
  (In thousands, except per share information)

 
Statements of Operations Data:                                
Collaboration revenue   $   $   $ 1,454   $   $ 1,037  
   
 
 
 
 
 
Operating expenses:                                
  Research and development     206     2,174     5,348     790     2,240  
  General and administrative     167     2,712     4,082     706     1,409  
   
 
 
 
 
 
Total operating expenses     373     4,886     9,430     1,496     3,649  
   
 
 
 
 
 
Loss from operations     (373 )   (4,886 )   (7,976 )   (1,496 )   (2,612 )
Interest income     2     17     74     3     41  
Interest expense             (43 )   (5 )   (11 )
   
 
 
 
 
 
Net loss     (371 )   (4,869 )   (7,945 )   (1,498 )   (2,582 )
Deemed dividend                     (20,389 )
Dividends and accretion to redeemable convertible preferred stock     (22 )   (520 )   (1,899 )   (164 )   (817 )
   
 
 
 
 
 
Net loss attributable to common stockholders   $ (393 ) $ (5,389 ) $ (9,844 ) $ (1,662 ) $ (23,788 )
   
 
 
 
 
 
Basic and diluted net loss attributable to common stockholders per common share   $ (6.74 ) $ (5.70 ) $ (5.02 ) $ (1.13 ) $ (9.04 )
   
 
 
 
 
 
Weighted average shares outstanding—basic and diluted     58     946     1,961     1,474     2,631  
   
 
 
 
 
 
Unaudited pro forma basic and diluted net loss attributable to common stockholders per common share               $ (0.92 )       $ (1.53 )
               
       
 
Unaudited pro forma weighted average shares outstanding—basic and diluted                 10,718           15,550  
               
       
 

        The pro forma as adjusted balance sheet data gives effect to our sale of 5,350,000 shares of common stock in this offering at an assumed initial public offering price of $14.00 per share, after deducting estimated underwriting discounts and commissions and offering expenses payable by us, and the automatic conversion of all outstanding shares of our convertible preferred stock at March 31, 2004 into an aggregate of 15,014,390 shares of common stock upon the completion of this offering.

 
  As of March 31, 2004
 
 
  Actual
  Pro Forma As
Adjusted

 
 
  Unaudited
(In thousands)

 
Balance Sheet Data:              
Cash and cash equivalents   $ 16,585   $ 84,835  
Short-term investments     14,615     14,615  
Working capital     31,223     99,473  
Total assets     34,516     102,766  
Line of credit obligation–net of current portion     289     289  
Redeemable convertible preferred stock     48,432      
Accumulated deficit     (39,417 )   (39,417 )
Total stockholders' equity (deficit)     (16,728 )   99,954  

6



RISK FACTORS

         This offering involves a high degree of risk. You should consider carefully the risks and uncertainties described below and the other information in this prospectus, including the financial statements and the related notes appearing at the end of this prospectus, before deciding to invest in shares of our common stock. If any of the following risks or uncertainties actually occurs, our business, prospects, financial condition and operating results would likely suffer, possibly materially. In that event, the market price of our common stock could decline and you could lose all or part of your investment.

Risks Relating to Our Business

We have a limited operating history and have incurred a cumulative loss since inception. If we do not generate significant revenues, we will not be profitable.

        We have incurred significant losses since our inception in May 2001. At March 31, 2004, our accumulated deficit was approximately $39.4 million. We have not generated revenues from the sale of any products to date. We expect that our annual operating losses will increase over the next several years as we expand our drug commercialization, development and discovery efforts. To become profitable, we must successfully develop and obtain regulatory approval for our existing drug candidates, and effectively manufacture, market and sell any drug candidates we develop. Accordingly, we may never generate significant revenues and, even if we do generate significant revenues, we may never achieve profitability.

        To become and remain profitable, we must succeed in developing and commercializing drugs with significant market potential. This will require us to be successful in a range of challenging activities for which we are only in the preliminary stages: developing drugs, obtaining regulatory approval for them, and manufacturing, marketing and selling them. We may never succeed in these activities and may never generate revenues that are significant or large enough to achieve profitability. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would depress the market price of our common stock and could impair our ability to raise capital, expand our business, diversify our product offerings or continue our operations.

If we fail to obtain approval of and commercialize our most advanced product candidate, M-Enoxaparin, we may have to curtail our product development programs and our business would be materially harmed.

        We have invested a significant portion of our time, financial resources and collaboration efforts in the development of our most advanced candidate, M-Enoxaparin, a technology-enabled generic version of Lovenox. To date, we have invested approximately $5.0 million on the development of M-Enoxaparin. Our near-term ability to generate revenues and our future success, in part, depends on the development and commercialization of M-Enoxaparin.

        We plan to prepare and submit an application to the FDA seeking to produce and market M-Enoxaparin in the United States. FDA approval of our application is required before marketing a generic equivalent of a drug previously approved under a new drug application, or NDA. If we are unable to obtain FDA approval for, and successfully commercialize M-Enoxaparin, we may never realize revenue from this product and we may have to curtail our other product development programs. As a result, our business would be materially harmed.

We will likely face intellectual property litigation with Aventis, the innovator of Lovenox.

        We will likely face costly and time consuming intellectual property litigation with Aventis, the innovator of Lovenox. Companies that produce branded pharmaceutical products for which there are unexpired patents listed in the FDA's Orange Book routinely bring patent infringement litigation

7



against applicants seeking FDA approval to manufacture and market generic forms of their branded products. In August 2003, Aventis sued Amphastar Pharmaceuticals, Inc., or Amphastar, and Teva Pharmaceuticals USA, Inc., or Teva, alleging, among other things, that the generic versions of Lovenox intended to be marketed by those companies infringe Aventis' Patent No. 5,389,618, which is scheduled to expire on February 14, 2012. We expect to face patent litigation if and when we submit our regulatory application for a generic version of Lovenox to the FDA. Litigation often involves significant expense and could delay or prevent the introduction of a generic product. Under most circumstances, the decision as to when to begin marketing M-Enoxaparin will be determined jointly by us and Sandoz. Sandoz, however, has sole discretion over the decision whether to market M-Enoxaparin under the following circumstance:

        Should Sandoz elect to proceed in this manner, we could face substantial patent liability damages, including possible treble damages, if a final court decision is adverse to us. Sandoz has agreed to indemnify us for these liabilities, subject to Sandoz's ability to offset certain of these liabilities against the profit-sharing amounts, the royalties and the commercial milestone payments otherwise due to us from the marketing of M-Enoxaparin. Further, if we are unsuccessful in any litigation, the court could issue a permanent injunction preventing us from marketing M-Enoxaparin for the life of Aventis' patent. In addition, Aventis has significantly greater resources than we do, and litigation with Aventis could last a number of years, potentially delaying or prohibiting the commercialization of M-Enoxaparin. Intellectual property litigation involves many risks and uncertainties, and there is no assurance that we will prevail in any lawsuit brought by Aventis. If we are not successful in commercializing M-Enoxaparin or are significantly delayed in doing so, we may have to curtail our product development programs and our business would be materially harmed.

We utilize new technologies in the development of some of our products that have not been reviewed or accepted by regulatory authorities.

        Some of our products in current or future development may be based on new technologies that have not been formally reviewed or accepted by the FDA or other regulatory authorities. Given the complexity of our technology, we intend to work closely with the FDA and other regulatory authorities to perform the requisite scientific analysis and evaluation of our methods to obtain regulatory approval for our products. It is possible that the validation process may take time and resources, require independent third-party analysis or not be accepted by the FDA and other regulatory authorities. For some products, the regulatory approval path and requirements may not be clear, which could add significant delay and expense. Delays or failure to obtain regulatory approval of any of the products that we develop would adversely affect our business.

8



If other generic versions of Lovenox are approved and successfully commercialized before M-Enoxaparin, our business would suffer.

        In mid 2003, Amphastar and Teva filed ANDAs for generic versions of Lovenox with the FDA. In addition, other third parties may seek approval to manufacture and market generic versions of Lovenox in the United States prior to our ANDA filing. If any of these parties obtain FDA approval under ANDA guidelines, we may not gain any competitive advantage, we may never achieve significant market share for M-Enoxaparin, our revenues would be reduced and, as a result, our business, including our future discovery and development programs, would suffer. In addition, under the Hatch-Waxman Act, any developer of a generic drug that is considered first to have its ANDA accepted for review by the FDA, and whose filing includes a certification that any patents listed with the FDA for the drug are invalid or not infringed by the manufacture, use or sale of the generic drug, or "paragraph IV" certification, may be eligible to receive a 180-day period of generic market exclusivity. In the event that any eligible 180-day exclusivity period has not begun and/or expired at the time we receive tentative approval for M-Enoxaparin, we may be forced to wait until the expiration of the exclusivity period before the FDA could make our approval effective and we could launch M-Enoxaparin.

If we fail to meet manufacturing requirements for M-Enoxaparin, our development and commercialization efforts may be materially harmed.

        We have limited personnel with experience in, and we do not own facilities for, manufacturing any products. We have entered into an agreement with Siegfried (USA), Inc. and Siegfried Ltd., pursuant to which Siegfried is further developing our M-Enoxaparin laboratory-scale processes, manufacturing the drug substance for M-Enoxaparin and providing certain other development services relating to M-Enoxaparin. We expect to depend on additional third parties to manufacture the drug product and provide analytical services with respect to M-Enoxaparin. We have not yet completed the manufacturing of a sufficient number of registration lots of M-Enoxaparin necessary to file our regulatory submission and we may run into unforeseen difficulties that may cause a delay in the filing.

        In addition, if the product is approved, in order to produce M-Enoxaparin in the quantities necessary to meet anticipated market demand, we and any contract manufacturer that we engage will need to increase manufacturing capacity. If we are unable to produce M-Enoxaparin in sufficient quantities to meet the requirements for the launch of the product or to meet future demand, our revenues and gross margins could be adversely affected.

Our revenues and profits from any of our generic product candidates may decline if our competitors introduce their own generic equivalents.

        In addition to general competition in the pharmaceutical market, we expect that certain of our generic product candidates may face intense and increasing competition from other manufacturers of generic and/or branded products. Revenues and gross profit derived from the sales of generic pharmaceutical products tend to follow a pattern based on certain regulatory and competitive factors. As patents for branded products and related exclusivity periods expire, manufacturers of generic products may receive regulatory approval for generic equivalents and may be able to achieve significant market penetration. As competing off-patent manufacturers receive regulatory approvals on similar products or as branded manufacturers launch generic versions of such products, market share, revenues and gross profit typically decline, in some cases, dramatically. If any of our generic product offerings, including M-Enoxaparin, enter markets with a number of competitors, we may not achieve significant market share, revenues or gross profit. In addition, as other generic products are introduced to the markets in which we participate, the market share, revenues and gross profit of our generic products could decline.

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Competition in the biotechnology and pharmaceutical industries is intense, and if we are unable to compete effectively, our financial results will suffer.

        The markets in which we intend to compete are undergoing, and are expected to continue to undergo, rapid and significant technological change. We expect competition to intensify as technological advances are made or new biotechnology products are introduced, such as alternatives to LMWHs or improved non-invasive delivery methods. New developments by competitors may render our current or future product candidates and/or technologies non-competitive, obsolete or not economical. Our competitors' products may be more efficacious or marketed and sold more effectively than any of our products.

        The pharmaceutical market is highly competitive and rapidly changing. Many of our competitors have:

        If we successfully develop and obtain approval for our drug candidates, we will face competition based on many different factors, including:

        Our competitors may develop or commercialize products with significant advantages in regard to any of these factors. Our competitors may therefore be more successful in commercializing their products than we are, which could adversely affect our competitive position and business.

If we are unable to establish and maintain our key customer arrangements, sales of our products and revenues would decline.

        Most generic pharmaceutical products are sold to customers through arrangements with group purchasing organizations, or GPOs. Generic pharmaceuticals are also sold through arrangements with retail organizations, mail order channels and other distributors. Many of the hospitals which make up M-Enoxaparin's target market contract with the GPO of their choice for their purchasing needs. We expect to derive a large percentage of our future revenue for M-Enoxaparin from customers that have relationships with a small number of GPOs. Currently, a relatively small number of GPOs control a large majority of sales to hospital customers. In order to establish and maintain relationships with major GPOs, we believe we need to maintain adequate drug supplies, remain price competitive, comply with FDA regulations and provide high-quality products. The GPOs with whom we hope to establish

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relationships may also have relationships with our competitors and may decide to contract for or otherwise prefer products other than ours. Typically, GPO agreements may be terminated on short notice. If we are unable to establish and maintain arrangements with major GPOs and customers, sales of our products, revenues and profits would decline.

Even if we receive approval to market our drug candidates, the market may not be receptive to our drug candidates upon their commercial introduction, which could prevent us from being profitable.

        Even if our drug candidates are successfully developed, our success and growth will also depend upon the acceptance of these drug candidates by physicians and third-party payors. Acceptance of our product development candidates will be a function of our products being clinically useful, being cost effective and demonstrating superior therapeutic effect with an acceptable side effect profile as compared to existing or future treatments. In addition, even if our products achieve market acceptance, we may not be able to maintain that market acceptance over time.

        Factors that we believe will materially affect market acceptance of our drug candidates under development include:


        If our products do not achieve market acceptance, we will not be able to generate sufficient revenues from product sales to maintain or grow our business.

We will require substantial additional funds to execute our business plan and, if additional capital is not available, we may need to limit, scale back or cease our operations.

        We will continue to require substantial funds to conduct research and development, preclinical testing and clinical trials of our development candidates, as well as funds necessary to manufacture and market any products that are approved for commercial sale. Because successful development of our drug candidates is uncertain, we are unable to estimate the actual funds we will require to complete research and development and commercialize our products under development.

        Our future capital requirements may vary depending on the following:

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        We anticipate that our current cash, cash equivalents and short-term investments, including $20.4 million in net proceeds received in connection with the issuance of our Series C convertible preferred stock in February 2004, and the expected net proceeds from this offering, will be sufficient to fund our operations for at least 36 months. We may seek additional funding in the future and intend to do so through collaborative arrangements and public or private equity and debt financings. Additional funds may not be available to us on acceptable terms or at all. In addition, the terms of any financing may adversely affect the holdings or the rights of our stockholders. If we are unable to obtain funding on a timely basis, we may be required to significantly curtail one or more of our research or development programs. We also could be required to seek funds through arrangements with collaborators or others that may require us to relinquish rights to some of our technologies, product candidates or products which we would otherwise pursue on our own.

If we are not able to retain our current senior management team or attract and retain qualified scientific, technical and business personnel, our business will suffer.

        We are dependent on the members of our senior management team, in particular, Ganesh Venkataraman, our Founder and Vice President of Technology, for our business success. Our employment agreements with Dr. Venkataraman and our other executive officers are terminable on short notice or no notice. We do not carry life insurance on the lives of any of our personnel. The loss of any of our executive officers would result in a significant loss in the knowledge and experience that we, as an organization, possess and could cause significant delays, or outright failure, in the development and approval of our product candidates. In addition, our growth will require us to hire a significant number of qualified scientific, commercial and administrative personnel. There is intense competition from numerous pharmaceutical and biotechnology companies, universities, governmental entities and other research institutions, for human resources, including management, in the technical fields in which we operate, and we may not be able to attract and retain qualified personnel necessary for the successful development and commercialization of our product candidates.

There is a substantial risk of product liability claims in our business. If we are unable to obtain sufficient insurance, a product liability claim against us could adversely affect our business.

        Our business exposes us to significant potential product liability risks that are inherent in the development, manufacturing and marketing of human therapeutic products. Product liability claims could delay or prevent completion of our development programs, clinical or otherwise. If we succeed in marketing products, such claims could result in a recall of our products or a change in the indications for which they may be used. We currently do not have any product liability insurance, but plan to obtain such insurance at appropriate levels prior to initiating studies in humans or clinical trials and at higher levels prior to marketing any of our drug candidates. Any insurance we obtain may not provide sufficient coverage against potential liabilities. Furthermore, clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance at a reasonable cost to protect us against losses that could have a material adverse effect on our business. These liabilities could prevent or interfere with our product development and commercialization efforts.

As we evolve from a company primarily involved in drug discovery and development into one that is also involved in the commercialization of drug products, we may have difficulty managing our growth and expanding our operations successfully.

        As the development of our drug candidates advance, we will need to expand our development, regulatory, manufacturing, sales and marketing capabilities or contract with other organizations to provide these capabilities for us. As our operations expand, we expect that we will need to manage additional relationships with various collaborative partners, suppliers and other organizations. Our ability to manage our operations and growth requires us to continue to improve our operational,

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financial and management controls, reporting systems and procedures. Such growth could place a strain on our administrative and operational infrastructure. We may not be able to make improvements to our management information and control systems in an efficient or timely manner and may discover deficiencies in existing systems and controls.

Risks Relating to Development and Regulatory Approval

If we are not able to demonstrate therapeutic equivalence for our generic versions of complex drugs, including our M-Enoxaparin and our M-Dalteparin products to the satisfaction of the FDA, we will not obtain regulatory approval for commercial sale of our generic product candidates and our future results of operations would be adversely affected.

        Our future results of operations depend, to a significant degree, on our ability to obtain regulatory approval for and commercialize generic versions of complex drugs, including M-Enoxaparin and M-Dalteparin. To obtain regulatory approval for the commercial sale of our generic versions of complex drugs, including M-Enoxaparin and M-Dalteparin, we will be required to demonstrate to the satisfaction of the FDA, among other things, that our generic products contain the same active ingredients, are of the same dosage strength, form, and route of administration, and meet compendial or other applicable standards for strength, quality, purity and identity, including potency. Our generic versions of complex drugs, including M-Enoxaparin and M-Dalteparin, must also be bioequivalent, meaning generally that there are no significant differences in the rate and extent to which the active ingredients are absorbed and become available at the site of drug action. Under current regulations, for certain drug products where bioequivalence is self-evident such as injectable solutions which have been shown to contain the same active and inactive ingredients as the listed drug, the FDA may waive the requirement for in vivo bioequivalence data.

        Determination of the same active ingredients for M-Enoxaparin and M-Dalteparin will be based on our demonstration of the chemical equivalence of our generic versions to Lovenox and Fragmin, respectively. The FDA may require confirmatory information, for example, animal testing, to determine the sameness of active ingredients and that any inactive ingredients or impurities do not compromise the product's safety and efficacy. Provision of sufficient information for approval may prove difficult and expensive. We must also demonstrate the adequacy of our methods, controls and facilities used in the manufacture of the product, including that they meet current good manufacturing practice, or cGMP. We cannot predict whether any of our generic product candidates will meet FDA requirements for approval.

        On February 19, 2003, a Citizen Petition was submitted to the FDA on behalf of Aventis requesting that the Commissioner of Food and Drugs withhold approval of any ANDA for a generic version of Lovenox until the conditions set forth in Aventis' petition are satisfied. In its petition, Aventis principally requested that, until enoxaparin has been fully characterized, the FDA refrain from approving any ANDA citing Lovenox as the reference listed drug, until the manufacturing process used to create the generic product is determined to be equivalent to Aventis' manufacturing process for Lovenox or the generic application is supported by proof of equivalent safety and effectiveness demonstrated through clinical trials. On February 12, 2004, Aventis submitted a supplement to its Citizen Petition, citing several new discoveries that supported its previous requests. To date, the FDA has not yet publicly responded to Aventis' requests nor has it issued any public interpretation of the guidelines for therapeutic equivalence as they may apply to LMWH products such as Lovenox or Fragmin. In the event that the FDA does not establish a standard for therapeutic equivalence with respect to generic versions of complex drugs, or requires us to conduct clinical trials or other lengthy processes, the commercialization of our technology-enabled generic product candidates could be delayed or prevented. Delays in any part of the process or our inability to obtain regulatory approval for our products could adversely affect our operating results by restricting or significantly delaying our introduction of new products.

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If our preclinical studies and clinical trials for our development candidates are not successful, we will not be able to obtain regulatory approval for commercial sale of our novel or improved drug candidates.

        To obtain regulatory approval for the commercial sale of our novel or improved drug candidates, we will be required to demonstrate through preclinical studies and clinical trials that our drug development candidates are safe and effective. Preclinical testing and clinical trials of new development candidates are lengthy and expensive and the historical failure rate for development candidates is high. The results from preclinical testing of a development candidate may not predict the results that will be obtained in human clinical trials. Clinical trials cannot commence until we submit an IND containing sufficient preclinical data and other information to support use in human subjects and the FDA allows the trials to go forward. Clinical trials must also be reviewed and approved by institutional review boards, or IRBs, for each clinical trial site before an investigational new drug may be used in a human trial at that site. We, the FDA or other applicable regulatory authorities may prohibit the initiation of, or suspend clinical trials of, a development candidate at any time if we or they believe the subjects or patients participating in such trials are being exposed to unacceptable health risks, or for other reasons. Adverse side effects of a development candidate on subjects or patients in a clinical trial could result in the FDA or other regulatory authorities refusing to approve a particular development candidate for any or all indications of use.

        Clinical trials of a new development candidate require the enrollment of a sufficient number of patients who are suffering from the disease the development candidate is intended to treat and who meet other eligibility criteria. Rates of patient enrollment are affected by many factors, including the size of the patient population, the nature of the protocol, the proximity of patients to clinical sites, the availability of effective treatments for the relevant disease and the eligibility criteria for the clinical trial. Lower than anticipated patient enrollment rates, high drop-out rates or inadequate drug supply or other materials, can result in increased costs and longer development times.

        We cannot predict whether any of our development candidates will encounter problems during clinical trials which will cause us or regulatory authorities to delay or suspend these trials, or which will delay the analysis of data from these trials. In addition, it is impossible to predict whether legislative changes will be enacted, or whether FDA regulations, guidance or interpretations will be changed, or what the impact of such changes, if any, may be. If we experience any such problems, we may not have the financial resources to continue development of the drug candidate that is affected or the development of any of our other drug candidates.

Failure to obtain regulatory approval in foreign jurisdictions would prevent us from marketing our products abroad.

        Although we have not initiated any marketing efforts in foreign jurisdictions, we intend in the future to market our products outside the United States. In order to market our products in the European Union and many other foreign jurisdictions, we must obtain separate regulatory approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval abroad may differ from that required to obtain FDA approval. The foreign regulatory approval process may include all of the risks associated with obtaining FDA approval and we may not obtain foreign regulatory approvals on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. We and our collaborators may not be able to file for regulatory approvals and may not receive necessary approvals to commercialize our products in any market outside the United States. The failure to obtain these approvals could materially adversely affect our business, financial condition and results of operations.

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Even if we obtain regulatory approvals, our marketed drugs will be subject to ongoing regulatory review. If we fail to comply with continuing United States and foreign regulations, we could lose our approvals to market drugs and our business would be seriously harmed.

        Even after approval, any drugs we develop will be subject to ongoing regulatory review, including the review of clinical results which are reported after our drug products are made commercially available. In addition, the manufacturer and manufacturing facilities we use to produce any of our drug candidates will be subject to periodic review and inspection by the FDA. We will be required to report any serious and unexpected adverse experiences and certain quality problems with our products and make other periodic reports to the FDA. The discovery of any previously unknown problems with the product, manufacturer or facility may result in restrictions on the drug or manufacturer or facility, including withdrawal of the drug from the market. Certain changes to an approved product, including in the way it is manufactured or promoted, often require prior FDA approval before the product as modified may be marketed. If we fail to comply with applicable continuing regulatory requirements, we may be subject to recalls, warning letters, civil penalties, suspension or withdrawal of regulatory approvals, product recalls and seizures, injunctions, operating restrictions and/or criminal prosecutions and penalties.

If third-party payors do not adequately reimburse customers for any of our product candidates that are approved for marketing, they might not be purchased or used, and our revenues and profits will not develop or increase.

        Our revenues and profits will depend heavily upon the availability of adequate reimbursement for the use of our approved product candidates from governmental and other third-party payors, both in the United States and in foreign markets. Reimbursement by a third-party payor may depend upon a number of factors, including the third-party payor's determination that use of a product is:


        Obtaining reimbursement approval for a product from each third-party and government payor is a time-consuming and costly process that could require us to provide supporting scientific, clinical and cost-effectiveness data for the use of our products to each payor. We may not be able to provide data sufficient to gain acceptance with respect to reimbursement. There also exists substantial uncertainty concerning third-party reimbursement for the use of any drug product incorporating new technology, and even if determined eligible, coverage may be more limited than the purposes for which the product is approved by the FDA. Moreover, eligibility for coverage does not imply that any product will be reimbursed in all cases or at a rate that allows us to make a profit or even cover our costs. Interim payments for new products, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may vary according to the use of the product and the clinical setting in which it is used, may be based on payments allowed for lower-cost products that are already reimbursed, may be incorporated into existing payments for other products or services, and may reflect budgetary constraints and/or imperfections in Medicare or Medicaid data used to calculate these rates. Net prices for products may be reduced by mandatory discounts or rebates required by government health care programs or by any future relaxation of laws that restrict imports of certain medical products from countries where they may be sold at lower prices than in the United States.

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        There have been, and we expect that there will continue to be, federal and state proposals to constrain expenditures for medical products and services, which may affect payments for our products. The Centers for Medicare and Medicaid Services frequently change product descriptors, coverage policies, product and service codes, payment methodologies and reimbursement values. Third-party payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates and may have sufficient market power to demand significant price reductions. As a result of actions by these third-party payors, the health care industry is experiencing a trend toward containing or reducing costs through various means, including lowering reimbursement rates, limiting therapeutic class coverage and negotiating reduced payment schedules with service providers for drug products.

        Our inability to promptly obtain coverage and profitable reimbursement rates from government-funded and private payors for our products could have a material adverse effect on our operating results and our overall financial condition.

New federal legislation will increase the pressure to reduce prices of pharmaceutical products paid for by Medicare, which could adversely affect our revenues, if any.

        The Medicare Prescription Drug Improvement and Modernization Act of 2003, or MMA, changes the way Medicare will cover and reimburse for pharmaceutical products. The legislation expands Medicare coverage for drug purchases by the elderly and eventually will introduce a new reimbursement methodology based on average sales prices for drugs. In addition, the new legislation provides authority for limiting the number of drugs that will be covered in any therapeutic class. As a result of the new legislation and the expansion of federal coverage of drug products, we expect that there will be additional pressure to contain and reduce costs. These cost reduction initiatives and other provisions of this legislation could decrease the coverage and price that we receive for our products and could seriously harm our business. While the MMA applies only to drug benefits for Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates, and any reduction in reimbursement that results from the MMA may result in a similar reduction in payments from private payors.

If legislative and regulatory lobbying efforts by manufacturers of branded products to limit the use of generics are successful, our sales of technology-enabled generic complex products may suffer.

        Many manufacturers of branded products have increasingly used both state and federal legislative and regulatory means to delay competition from manufacturers of generic drugs. These efforts have included:

        In addition, some manufacturers of branded products have engaged in state-by-state initiatives to enact legislation that restrict the substitution of some branded drugs with generic drugs.

        If these efforts to delay or block competition are successful, we may be unable to sell our generic products, which could have a material adverse effect on our sales and profitability.

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Foreign governments tend to impose strict price controls, which may adversely affect our revenues, if any.

        In some foreign countries, particularly the countries of the European Union, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be adversely affected.

If we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected.

        Our research and development involves, and may in the future involve, the use of hazardous materials and chemicals, including sodium azide, cetylpyridinium chloride monohydrate, 4-chlorobenzyl chloride, sodium nitrite pyridine, sodium cyanoborohydride and barium acetate. For the fiscal years ended 2001, 2002 and 2003, we spent approximately $0, $10,000 and $17,500 respectively, in order to comply with environmental and waste disposal regulations. Although we believe that our safety procedures for handling and disposing of these materials comply with the standards mandated by state and federal regulations, the risk of accidental contamination or injury from these materials cannot be eliminated. If an accident occurs, we could be held liable for resulting damages, which could be substantial. We are also subject to numerous environmental, health and workplace safety laws and regulations, including those governing laboratory procedures, exposure to blood-borne pathogens and the handling of biohazardous materials. Although we maintain workers' compensation insurance as prescribed by the Commonwealth of Massachusetts to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of these materials, this insurance may not provide adequate coverage against potential liabilities. For claims not covered by workers' compensation insurance, we also maintain an employer's liability insurance policy in the amount of $3.5 million per occurrence and in the aggregate. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us. Additional federal, state and local laws and regulations affecting our operations may be adopted in the future. We may incur substantial costs to comply with, and substantial fines or penalties if we violate, any of these laws or regulations.


Risks Relating to Our Dependence on Third Parties

Our collaboration with Sandoz is important to our business. If Sandoz fails to adequately perform under our collaboration or terminates our collaboration, the development and commercialization of injectable enoxaparin would be delayed or terminated and our business would be adversely affected.

        In November 2003, we entered into a collaboration and license agreement with Sandoz to jointly develop and commercialize injectable enoxaparin and certain improved injectable forms of enoxaparin. Under the terms of the agreement, we and Sandoz agree to exclusively work with each other in the development and commercialization of injectable enoxaparin within the United States. If Sandoz fails to adequately perform under our collaboration and license agreement, we may not successfully commercialize M-Enoxaparin and may be precluded from seeking alternative collaborative opportunities because of our exclusivity commitment. We have also granted to Sandoz the right to negotiate additional rights under certain circumstances.

        Sandoz may terminate our collaboration agreement for material uncured breaches or certain events of bankruptcy or insolvency by us. Sandoz may also terminate the collaboration agreement if the product or the market lacks commercial viability, if we fail to meet certain development milestones, if new laws or regulations are passed or court decisions rendered that substantially diminish our legal avenues for redress, or, in multiple cases, if certain costs exceed mutually agreed upon limits. If Sandoz

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terminates the agreement other than due to our uncured breach, we will be granted an exclusive license under certain intellectual property of Sandoz to develop and commercialize injectable enoxaparin in the United States. In that event, we would need to expand our internal capabilities or enter into another collaboration. In such event, significant delays would be likely to occur and could prevent us from completing the development and commercialization of injectable enoxaparin.

        If Sandoz terminates the agreement due to our uncured breach, Sandoz would retain the exclusive right to develop and commercialize injectable enoxaparin in the United States. In that event, although the profit sharing, royalty and milestone payment obligations of Sandoz would survive, we would no longer have any influence over the development or commercialization strategy. In addition, if Sandoz were to terminate the agreement due to our uncured breach, Sandoz would retain its rights of first negotiation with respect to certain of our other products in certain circumstances and its rights of first refusal outside of the United States. Accordingly, if Sandoz terminates the agreement, our introduction of M-Enoxaparin may be significantly delayed, we may decide to discontinue the M-Enoxaparin project, or our revenues may be reduced, any one of which could materially affect our business.

We depend on third-party manufacturers to manufacture products for us. If in the future we encounter difficulties in our supply or manufacturing arrangements, our business may be materially affected.

        We have limited personnel with experience in, and we do not own facilities for, manufacturing any products. In addition, we do not have, and do not intend to develop, the ability to manufacture material for our clinical trials or at commercial scale. For our M-Enoxaparin program, we have entered into an agreement with Siegfried (USA), Inc. and Siegfried Ltd., pursuant to which, among other things, Siegfried will provide us with the M-Enoxaparin drug substance required for our ANDA filing. To develop our drug candidates, apply for regulatory approvals and commercialize any products, we or our partners need to contract for or otherwise arrange for the necessary manufacturing facilities and capabilities. As a result, we would generally rely on contract manufacturers for regulatory compliance and quality assurance for our products. If our contract manufacturers were to breach or terminate their manufacturing arrangements with us, the development or commercialization of the affected products or drug candidates could be delayed, which could have an adverse affect on our business. In addition, any change in our manufacturers could be costly because the commercial terms of any new arrangement could be less favorable and because the expenses relating to the transfer of necessary technology and processes could be significant.

        We have relied upon third parties to produce material for preclinical studies and may continue to do so in the future. Although we believe that we will not have any material supply issues, we cannot be certain that we will be able to obtain long-term supply arrangements of those materials on acceptable terms, if at all. If we are unable to arrange for third-party manufacturing, or to do so on commercially reasonable terms, we may not be able to complete development of our products or market them.

        In addition, the FDA and other regulatory authorities require that our products be manufactured according to cGMP regulations. Any failure by us or our third-party manufacturers to comply with cGMP, and/or our failure to scale-up our manufacturing processes could lead to a delay in, or failure to obtain, regulatory approval. In addition, such failure could be the basis for action by the FDA to withdraw approvals for drug candidates previously granted to us and for other regulatory action. To the extent we rely on a third-party manufacturer, the risk of non-compliance with cGMPs may be greater and the ability to effect corrective actions for any such noncompliances may be compromised or delayed.

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We may need to enter into alliances with other companies that can provide capabilities and funds for the development and commercialization of our drug candidates. If we are unsuccessful in forming or maintaining these alliances on favorable terms, our business could be adversely affected.

        Because we have limited or no capabilities for drug development, manufacturing, sales, marketing and distribution, we may need to enter into alliances with other companies that can assist with the development and commercialization of our drug candidates. We may, for example, form alliances with major pharmaceutical companies to jointly develop specific drug candidates and to jointly commercialize them if they are approved. In such alliances, we would expect our pharmaceutical company partners to provide substantial capabilities in clinical development, manufacturing, regulatory affairs, sales and marketing. We may not be successful in entering into any such alliances. Even if we do succeed in securing such alliances, we may not be able to maintain them if, for example, development or approval of a drug candidate is delayed or sales of an approved drug are disappointing. If we are unable to secure or maintain such alliances we may not have the capabilities necessary to continue or complete development of our drug candidates and bring them to market, which may have an adverse effect on our business.

        In addition to capabilities, we may depend on our alliances with other companies to provide substantial additional funding for development and potential commercialization of our drug candidates. We may not be able to obtain funding on favorable terms from these alliances, and if we are not successful in doing so, we may not have sufficient funds to develop a particular drug candidate internally, or to bring drug candidates to market. Failure to bring our drug candidates to market will prevent us from generating sales revenues, and this may substantially harm our business. Furthermore, any delay in entering into these alliances could delay the development and commercialization of our drug candidates and reduce their competitiveness even if they reach the market. As a result, our business may be adversely affected.

If any collaborative partner terminates or fails to perform its obligations under agreements with us, the development and commercialization of our drug candidates could be delayed or terminated.

        Our continued and expected dependence on collaborative partners for their drug development, manufacturing, sales, marketing and distribution capabilities, as well as for their financial support means that our business would be adversely affected if a partner terminates its collaboration agreement with us or fails to perform its obligations under the agreement. Our current collaborations and future collaborations, if any, may not be scientifically or commercially successful. Factors that may affect the success of our collaborations include the following:

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        If any of these occur, the development and commercialization of one or more drug candidates could be delayed, curtailed or terminated because we may not have sufficient financial resources or capabilities to continue such development and commercialization.

If we are unable to establish sales and marketing capabilities or enter into agreements with third parties to market and sell our product candidates, we may be unable to generate product revenues.

        We do not have a sales organization and have no experience as a company in the sales, marketing and distribution of pharmaceutical products. There are risks involved with establishing our own sales and marketing capabilities, as well as entering into arrangements with third parties to perform these services. For example, developing a sales force is expensive and time consuming and could delay any product launch. In addition, to the extent that we enter into arrangements with third parties to perform sales, marketing and distribution services, we will have less control over sales of our products, and our future revenues would depend heavily on the success of the efforts of these third parties.

Our collaborations with outside scientists and consultants may be subject to restriction and change.

        We work with chemists, biologists and other scientists at academic and other institutions, and consultants who assist us in our research, development, regulatory and commercial efforts. These scientists and consultants have provided, and we expect that they will continue to provide, valuable advice on our programs. These scientists and consultants are not our employees, may have other commitments that would limit their future availability to us and typically will not enter into non-compete agreements with us. If a conflict of interest arises between their work for us and their work for another entity, we may lose their services. In addition, we will be unable to prevent them from establishing competing businesses or developing competing products.

We enter into various contracts in the normal course of our business that periodically incorporate provisions whereby we indemnify the other party to the contract. In the event we would have to perform under these indemnification provisions, it could have a material adverse effect on our business, financial position and results of operations.

        In the normal course of business, we periodically enter into academic, commercial and consulting agreements that contain indemnification provisions. With respect to our academic agreements, we typically indemnify the institution and related parties from losses arising from claims relating to the products, processes or services made, used, sold or performed pursuant to the agreements for which we have secured licenses, and from claims arising from our or our sublicensees' exercise of rights under the agreement. With respect to our commercial agreements, the bulk of which are with contract manufacturers, we indemnify our vendors from third party product liability claims which result from the production, use or consumption of the product, as well as for certain alleged infringements of any patent or other intellectual property right by a third party. With respect to consultants, we indemnify them from claims arising from the good faith performance of their services. In all of the above cases, we do not indemnify the parties for claims resulting from the negligence or willful misconduct of the indemnified party.

        We maintain insurance coverage which we believe will limit our obligations under these indemnification provisions. With respect to M-Enoxaparin, we are also protected under certain circumstances through the indemnification provided to us by Sandoz. However, should our obligation under an indemnification provision exceed applicable insurance coverage or if we were denied insurance coverage, our business, financial position and results of operations could be adversely affected and the market value of our common stock could decline. Similarly, if we are relying on a collaborator to indemnify us and the collaborator is denied insurance coverage or the indemnification obligation exceeds the applicable insurance coverage, and if the collaborator does not have other assets

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available to indemnify us, our business, financial position and results of operations could be adversely affected.

Risks Relating to Patents and Licenses

If we are not able to obtain and enforce patent protection for our discoveries, our ability to successfully commercialize our product candidates will be harmed and we may not be able to operate our business profitably.

        Our success depends, in part, on our ability to protect proprietary methods and technologies that we develop under the patent and other intellectual property laws of the United States and other countries, so that we can prevent others from using our inventions and proprietary information. However, we may not hold proprietary rights to some patents related to our current or future product candidates. Because patent applications in the United States and many foreign jurisdictions are typically not published until 18 months after filing, or in some cases not at all, and because publications of discoveries in scientific literature lag behind actual discoveries, we cannot be certain that we were the first to make the inventions claimed in issued patents or pending patent applications, or that we were the first to file for protection of the inventions set forth in our patent applications. As a result, we may be required to obtain licenses under third-party patents to market our proposed products. If licenses are not available to us on acceptable terms, or at all, we will not be able to market the affected products.

        Our strategy depends on our ability to rapidly identify and seek patent protection for our discoveries. This process is expensive and time consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. Despite our efforts to protect our proprietary rights, unauthorized parties may be able to obtain and use information that we regard as proprietary. The issuance of a patent does not guarantee that it is valid or enforceable, so even if we obtain patents, they may not be valid or enforceable against third parties. In addition, the issuance of a patent does not guarantee that we have the right to practice the patented invention. Third parties may have blocking patents that could be used to prevent us from marketing our own patented product and practicing our own patented technology.

        Our pending patent applications may not result in issued patents. The patent position of pharmaceutical or biotechnology companies, including ours, is generally uncertain and involves complex legal and factual considerations. The standards which the United States Patent and Trademark Office and its foreign counterparts use to grant patents are not always applied predictably or uniformly and can change. There is also no uniform, worldwide policy regarding the subject matter and scope of claims granted or allowable in pharmaceutical or biotechnology patents. The laws of some foreign countries do not protect proprietary information to the same extent as the laws of the United States, and many companies have encountered significant problems and costs in protecting their proprietary information in these foreign countries. Accordingly, we do not know the degree of future protection for our proprietary rights or the breadth of claims allowed in any patents issued to us or to others. The allowance of broader claims may increase the incidence and cost of patent interference proceedings and/or opposition proceedings, and the risk of infringement litigation. On the other hand, the allowance of narrower claims may limit the value of our proprietary rights. Our issued patents may not contain claims sufficiently broad to protect us against third parties with similar technologies or products, or provide us with any competitive advantage. Moreover, once they have issued, our patents and any patent for which we have licensed or may license rights may be challenged, narrowed, invalidated or circumvented. If our patents are invalidated or otherwise limited, other companies will be better able to develop products that compete with ours, which could adversely affect our competitive business position, business prospects and financial condition.

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        We also rely on trade secrets, know-how and technology, which are not protected by patents, to maintain our competitive position. If any trade secret, know-how or other technology not protected by a patent were to be disclosed to or independently developed by a competitor, our business and financial condition could be materially adversely affected.

Our competitors may allege that we are infringing their intellectual property, forcing us to expend substantial resources in resulting litigation, the outcome of which would be uncertain. Any unfavorable outcome of such litigation could have a material adverse effect on our business, financial position and results of operations.

        If any parties successfully claim that our creation or use of proprietary technologies infringes upon their intellectual property rights, we might be forced to incur expenses to litigate the claims, pay damages, potentially including treble damages, if we are found to have willfully infringed such parties' patent rights. In addition, if we are unsuccessful in litigation, a court could issue a permanent injunction preventing us from marketing and selling the patented drug or other technology for the life of the patent that we have been deemed to have infringed. Litigation concerning patents, other forms of intellectual property and proprietary technologies is becoming more widespread and can be protracted and expensive, and can distract management and other key personnel from performing their duties for us.

        Any legal action against us or our collaborators claiming damages and seeking to enjoin commercial activities relating to the affected products, and processes could, in addition to subjecting us to potential liability for damages, require us or our collaborators to obtain a license in order to continue to manufacture or market the affected products and processes. Any license required under any patent may not be made available on commercially acceptable terms, if at all. In addition, some licenses may be non-exclusive, and therefore, our competitors may have access to the same technology licensed to us. If we fail to obtain a required license or are unable to design around a patent, we may be unable to effectively market some of our technology and products, which could limit our ability to generate revenues or achieve profitability and possibly prevent us from generating revenue sufficient to sustain our operations.

If we become involved in patent litigation or other proceedings to enforce our patent rights, we could incur substantial costs, substantial liability for damages and be required to stop our product commercialization efforts.

        We may need to resort to litigation to enforce a patent issued to us or to determine the scope and validity of third-party proprietary rights. The cost to us of any litigation or other proceeding relating to intellectual property rights, even if resolved in our favor, could be substantial, and the litigation could divert our management's efforts. Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. Uncertainties resulting from the initiation and continuation of any litigation could limit our ability to continue our operations.

We in-license a significant portion of our proprietary technologies and if we fail to comply with our obligations under any of the related agreements, we could lose license rights that are necessary to develop our product candidates.

        We are a party to and rely on a number of in-license agreements with third parties, such as those with the Massachusetts Institute of Technology, that give us rights to intellectual property that is necessary for our business. In addition, we expect to enter into additional licenses in the future. Our current in-license arrangements impose various development, royalty and other obligations on us. If we breach these obligations, these exclusive licenses could be converted to non-exclusive licenses or the

22



agreements could be terminated, which would result in our being unable to develop, manufacture and sell products that are covered by the licensed technology.

Confidentiality agreements with employees and others may not adequately prevent disclosure of trade secrets and other proprietary information.

        In order to protect our proprietary technology and processes, we also rely in part on confidentiality agreements with our corporate partners, employees, consultants, outside scientific collaborators and sponsored researchers, advisors and others. These agreements may not effectively prevent disclosure of confidential information and may not provide an adequate remedy in the event of unauthorized disclosure of confidential information. In addition, others may independently discover trade secrets and proprietary information, and in such cases we could not assert any trade secret rights against such party. Costly and time consuming litigation could be necessary to enforce and determine the scope of our proprietary rights, and failure to obtain or maintain trade secret protection could adversely affect our competitive business position.

Risks Relating to This Offering

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

        We cannot specify with certainty the particular uses of the net proceeds that we will receive from this offering. Our management will have broad discretion in the application of the net proceeds, including for any of the purposes described in the "Use of Proceeds" section of this prospectus. Our stockholders may not agree with the manner in which our management chooses to allocate and spend the net proceeds. The failure by our management to apply these funds effectively could have a material adverse effect on our business. Pending their use, we may invest the net proceeds from this offering in a manner that does not produce income or that loses value.

If you purchase our common stock in this offering, you will incur immediate and substantial dilution in the book value of your shares.

        The assumed initial public offering price is substantially higher than the net tangible book value per share of our common stock. Investors purchasing common stock in this offering will pay a price per share that substantially exceeds the book value of our tangible assets after subtracting our liabilities. As a result, investors purchasing common stock in this offering will incur immediate dilution of $9.93 per share, based on an assumed initial public offering price of $14.00 per share. Further, investors purchasing common stock in this offering will contribute approximately 62% of the total amount invested by stockholders since our inception, but will own only approximately 22% of the shares of common stock outstanding.

        This dilution is due to our investors who purchased shares prior to this offering having paid substantially less than the price offered to the public in this offering when they purchased their shares and the exercise of stock options granted to our employees. As of April 30, 2004, options to purchase 1,148,900 shares of common stock at a weighted average exercise price of $0.64 per share were outstanding, and a warrant to purchase 12,500 shares of our Series A double prime convertible preferred stock, with an exercise price of $2.87, was outstanding. After this offering, this warrant will be exercisable for 16,000 shares of common stock at an exercise price of $2.2422 per common share. The exercise of any of these options or the warrant would result in additional dilution. As a result of this dilution, investors purchasing stock in this offering may receive significantly less than the purchase price paid in this offering in the event of a liquidation.

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Our stock price is likely to be volatile, and the market price of our common stock after this offering may drop below the price you pay.

        Prior to this offering, there has been no public market for our common stock, and an active public market for our common stock may not develop or continue after this offering. If you purchase shares of our common stock in this offering, you will not pay a price established in a public marketplace. Rather, you will pay the price that we negotiate with the underwriters, which may not be indicative of market prices.

        Market prices for securities of biotechnology companies have been particularly volatile. Some of the factors that may cause the market price of our common stock to fluctuate include:


        If any of these factors causes an adverse effect on our business, results of operations or financial condition, the price of our common stock could fall.

An active trading market for our common stock may not develop.

        Prior to this offering, there has been no public market for our common stock. Although we have applied to have our common stock approved for quotation on the NASDAQ National Market, an active trading market for our shares may never develop or be sustained following this offering. The initial public offering price for our common stock will be determined through negotiations with the underwriters. This initial public offering price may vary from the market price of our common stock after the offering. Investors may not be able to sell their common stock at or above the initial public offering price.

Insiders will continue to have substantial control over Momenta after this offering and could delay or prevent a change in corporate control.

        After this offering, our directors, executive officers and principal stockholders, together with their affiliates, will beneficially own, in the aggregate, approximately 70.6% of our outstanding common stock, or 68.4% if the underwriters exercise their over-allotment option. As a result, these stockholders, if acting together, may have the ability to determine the outcome of matters submitted to our stockholders for approval, including the election and removal of directors and any merger,

24



consolidation or sale of all or substantially all of our assets. In addition, these persons, acting together, may have the ability to control the management and affairs of our company. Accordingly, this concentration of ownership may harm the market price of our common stock by:

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

        Provisions in our certificate of incorporation and our by-laws that will become effective upon the completion of this offering may delay or prevent an acquisition of us or a change in our management. In addition, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Because our board of directors is responsible for appointing the members of our management team, these provisions could in turn affect any attempt by our stockholders to replace current members of our management team. These provisions include:


        Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with us for a period of three years after the date of the transaction in which the person acquired in excess of 15% of our outstanding voting stock, unless the merger or combination is approved in a prescribed manner. Finally, these provisions establish advance notice requirements for nominations for election to our board of directors or for proposing matters that can be acted upon at stockholder meetings. These provisions would apply even if the offer may be considered beneficial by some stockholders.

If there are substantial sales of our common stock, our stock price could decline.

        If our existing stockholders sell a large number of shares of our common stock or the public market perceives that existing stockholders might sell shares of common stock, the market price of our common stock could decline significantly. All of the shares being sold in this offering will be freely tradable without restriction or further registration under the federal securities laws, unless purchased by our "affiliates" as that term is defined in Rule 144 under the Securities Act.

        After this offering, we will have outstanding 24,563,183 shares of common stock based on the number of shares outstanding as of April 30, 2004. This includes the 5,350,000 shares that we are selling in this offering, which may be resold in the public market immediately. The remaining

25



19,213,183 shares, or 78.2% of our outstanding shares after this offering, are currently restricted as a result of securities laws or lock-up agreements but will be able to be sold in the near future as set forth below.

Number of Shares and % of Total Outstanding

  Date Available for Sale Into Public Market
31,120 shares, or 0.16%   Beginning 90 days after the completion of this offering, depending on the requirements of the federal securities laws.

15,792,606 shares, or 82.2%

 

180 days after the date of this prospectus due to lock-up agreements between the holders of these shares and the underwriters. However, the underwriters can waive the provisions of these lock-up agreements and allow these stockholders to sell their shares at any time.

3,389,457 shares, or 17.64%

 

Between 180 and 365 days after the date of this prospectus, depending on the applicable requirements of the federal securities laws.

        Upon completion of this offering, subject to certain conditions, holders of an aggregate of approximately 18,601,275 shares of common stock will have rights with respect to the registration of these shares of common stock with the Securities and Exchange Commission. If we register their shares of common stock following the expiration of the lock-up agreements, they can sell those shares in the public market.

        Promptly following this offering, we intend to register approximately 5,717,380 shares of common stock that are authorized for issuance under our stock plans, employee stock purchase plan and outstanding stock options. As of April 30, 2004, 1,148,900 shares were subject to outstanding options. Once we register the shares authorized for issuance under our stock plans, they can be freely sold in the public market upon issuance, subject to the lock-up agreements referred to above and the restrictions imposed on our affiliates under Rule 144.

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SPECIAL NOTE REGARDING FORWARD-LOOKING INFORMATION

        This prospectus contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, included in this prospectus regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management are forward-looking statements. The words "anticipates," "believes," "estimates," "expects," "intends," "may," "plans," "projects," "will," "would" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this prospectus, particularly in the "Risk Factors" section, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements.


NOTICES TO INVESTORS

        You should rely only on the information contained in this prospectus. We have not authorized anyone to provide you with information different from that contained in this prospectus. We are offering to sell shares of common stock and seeking offers to buy shares of common stock only in jurisdictions where offers and sales are permitted. The information contained in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or any sale of the common stock.

        For investors outside the United States: Neither we nor any of the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourselves about and to observe any restrictions relating to this offering and the distribution of this prospectus.

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USE OF PROCEEDS

        We estimate that our net proceeds from the sale of 5,350,000 shares of common stock in this offering will be approximately $68.3 million, assuming an initial public offering price of $14.00 per share and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. If the underwriters exercise their over-allotment option, we estimate that we will receive additional net proceeds of approximately $10.5 million. We intend to use the majority of the net proceeds to fund:

        We anticipate using the remaining net proceeds of this offering to fund:

        In addition, we may also use a portion of the proceeds for the acquisition of, or investment in, companies, technologies, products or assets that complement our business. However, we have no present understandings, commitments or agreements to enter into any potential acquisitions or investments.

        The amounts and timing of our actual expenditures will depend upon numerous factors, including the timing and success of any clinical trials we may commence in the future, the timing of regulatory submissions, the status of our research and development efforts and timing, the amount of proceeds actually raised in this offering, the amount of cash generated by our operations, the amount of competition we face and the success we have with obtaining any required licenses and entering into collaboration arrangements. As a result, our management will have broad discretion to allocate the net proceeds from this offering. Pending utilization of the net proceeds as described above, we intend to invest the net proceeds of the offering in short-term investment grade and U.S. government securities.


DIVIDEND POLICY

        We have never paid or declared any cash dividends on our common stock. We currently intend to retain earnings, if any, to finance the growth and development of our business and we do not expect to pay any cash dividends on our common stock in the foreseeable future. Payment of future dividends, if any, will be at the discretion of our board of directors and will depend on our financial condition, results of operations, capital requirements, restrictions contained in current or future financing instruments and other factors our board of directors deems relevant.

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CAPITALIZATION

        The following table sets forth our capitalization as of March 31, 2004:

        You should read this table together with our financial statements and the related notes appearing at the end of this prospectus and the "Management's Discussion and Analysis of Financial Condition and Results of Operations" section of this prospectus.

 
  As of March 31, 2004
 
 
  Actual
  Pro Forma As
Adjusted

 
 
  (In thousands)

 

Cash and cash equivalents and short-term investments

 

$

31,200

 

$

99,450

 
   
 
 

Line of credit obligation—net of current portion

 

 

289

 

$

289

 
Redeemable convertible preferred stock, $0.01 par value per share; 12,000,000 shares authorized actual and no shares authorized pro forma as adjusted; 11,730,012 shares outstanding actual and no shares outstanding pro forma as adjusted     48,432      

Stockholders' equity (deficit):

 

 

 

 

 

 

 
Preferred stock, par value $0.01 per share; no shares authorized actual and 5,000,000 shares authorized pro forma as adjusted; no shares outstanding actual and pro forma as adjusted          
Common stock, par value $0.0001 per share; 30,000,000 and 100,000,000 shares authorized actual and pro forma as adjusted, respectively; 4,193,355 shares outstanding actual and 24,557,745 shares outstanding pro forma as adjusted         2  
Additional paid-in capital     25,963     142,643  
Accumulated other comprehensive loss     (7 )   (7 )
Due from officer     (35 )   (35 )
Deferred compensation     (3,231 )   (3,231 )
Accumulated deficit     (39,417 )   (39,417 )
   
 
 
  Total stockholders' equity (deficit)     (16,728 )   99,955  
   
 
 
Total capitalization   $ 31,993   $ 100,244  
   
 
 

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        The above data excludes:

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DILUTION

        Our historical net tangible book value as of March 31, 2004 was a deficit of $16.7 million, or $3.99 per share, based on 4,193,355 shares of common stock outstanding as of March 31, 2004. Historical net tangible book value per share is determined by dividing our total tangible assets less total liabilities and redeemable convertible preferred stock by the actual number of outstanding shares of our common stock. Our pro forma net tangible book value as of March 31, 2004 was $31.7 million, or $1.65 per share, based on 19,207,745 shares of common stock outstanding after giving effect to the automatic conversion of all outstanding shares of our redeemable convertible preferred stock into common stock upon the closing of this offering. Pro forma net tangible book value per share represents the amount of our total tangible assets less total liabilities, divided by the pro forma number of shares of common stock outstanding before giving effect to this offering.

        After giving effect to our sale of 5,350,000 shares of common stock in this offering, at an assumed initial public offering price of $14.00 per share, less estimated underwriting discounts and commissions and offering expenses payable by us, our pro forma net tangible book value as of March 31, 2004 would have been $4.07 per share. This represents an immediate increase in pro forma net tangible book value per share of $8.06 to existing stockholders and immediate dilution in pro forma net tangible book value of $9.93 per share to new investors purchasing our common stock in the offering at the assumed initial public offering price. Dilution per share to new investors is determined by subtracting pro forma net tangible book value per share after this offering from the initial public offering price per share paid by a new investor. The following table illustrates the per share dilution without giving effect to the over-allotment option granted to the underwriters:

  Assumed initial public offering price per share       $ 14.00
    Historical net tangible book value per share at March 31, 2004   (3.99 )    
    Increase per share attributable to the conversion of redeemable convertible preferred stock   5.64      
   
     
    Pro forma net tangible book value per share at March 31, 2004   1.65      
    Increase per share attributable to new investors   2.42      
   
     
  Pro forma net tangible book value per share after the offering         4.07
       
  Dilution of net tangible book value per share to new investors       $ 9.93
       

        If the underwriters exercise their over-allotment option in full, the pro forma net tangible book value per share after the offering would be $4.35 per share, the increase in net tangible book value per share to existing stockholders would be $8.34 per share and the dilution to new investors would be $9.65 per share.

        The following table summarizes, on a pro forma basis, as of March 31, 2004, the differences between the number of shares of common stock purchased from us, the total cash consideration paid and the average price per share paid by our existing stockholders and by new investors in this offering. We have used the initial public offering price of $14.00 per share, and have not deducted the underwriting discount and commissions and other expenses of the offering in our calculations:

 
  Shares Purchased
  Total Consideration
   
 
  Average Price
Per Share

 
  Number
  Percent
  Amount
  Percent
Existing stockholders   19,207,745   78.2 % $ 45,983,406   38.0 % $ 2.39
New investors   5,350,000   21.8     74,900,000   62.0     14.00
   
 
 
 
     
  Total   24,557,745   100.0 %   120,883,406   100.0 %    
   
 
 
 
     

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        The share data in the table above is based on shares outstanding as of March 31, 2004 and excludes:

        If the underwriters' over-allotment option is exercised in full, the following will occur:

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SELECTED FINANCIAL AND OPERATING DATA

        You should read the following selected financial information together with our financial statements and the related notes appearing at the end of this prospectus and the "Management's Discussion and Analysis of Financial Condition and Results of Operations" section of this prospectus. We have derived the statement of operations data for the three months ended March 31, 2003 and 2004 and the balance sheet data at March 31, 2004 from our unaudited financial statements which are included in this prospectus. The unaudited financial statements have been prepared on the same basis as the audited financial statements and, in the opinion of management, include all adjustments, consisting only of normal recurring adjustments necessary for a fair presentation of the information set forth therein. We have derived the statement of operations data for the period from inception (May 17, 2001) through December 31, 2001, or Fiscal 2001, and for the years ended December 31, 2002 and 2003, or Fiscal 2002 and 2003, respectively, and the balance sheet information at December 31, 2002 and 2003 from our audited financial statements which are included in this prospectus. We have derived the balance sheet data at December 31, 2001 from our audited financial statements, which are not included in this prospectus. Our historical results for any prior period are not necessarily indicative of results to be expected for any future period. The pro forma net loss attributable to common stockholders per share information is computed using the weighted average number of common shares outstanding, after giving pro forma effect to the automatic conversion of all shares of our redeemable convertible preferred stock outstanding at March 31, 2004 into shares of our common stock effective upon the completion of this offering, as if the conversion had occurred at the date of the original issuance. This pro forma data does not give effect to the issuance of common stock upon the exercise of outstanding stock options or the outstanding warrant.

 
  Period from
Inception
(May 17, 2001)
through
December 31, 2001

  Year Ended
December 31,

  Three Months
Ended March 31,

 
 
  2002
  2003
  2003
  2004
 
 
  (In thousands, except per share information)

 
Statements of Operations Data:                                
Collaboration revenue   $   $   $ 1,454   $   $ 1,037  
   
 
 
 
 
 
Operating expenses:                                
  Research and development     206     2,174     5,348     790     2,240  
  General and administrative     167     2,712     4,082     706     1,409  
   
 
 
 
 
 
Total operating expenses     373     4,886     9,430     1,496     3,649  
   
 
 
 
 
 
Loss from operations     (373 )   (4,886 )   (7,976 )   (1,496 )   (2,612 )
Interest income     2     17     74     3     41  
Interest expense             (43 )   (5 )   (11 )
   
 
 
 
 
 
Net loss     (371 )   (4,869 )   (7,945 )   (1,498 )   (2,582 )
Deemed dividend                     (20,389 )
Dividends and accretion to redeemable convertible preferred stock     (22 )   (520 )   (1,899 )   (164 )   (817 )
   
 
 
 
 
 
Net loss attributable to common stockholders   $ (393 ) $ (5,389 ) $ (9,844 ) $ (1,662 ) $ (23,788 )
   
 
 
 
 
 
Basic and diluted net loss attributable to common stockholders per common share   $ (6.74 ) $ (5.70 ) $ (5.02 ) $ (1.13 ) $ (9.04 )
   
 
 
 
 
 
Weighted average shares outstanding—basic and diluted     58     946     1,961     1,474     2,631  
   
 
 
 
 
 
Unaudited pro forma basic and diluted net loss attributable to common stockholders per common share               $ (0.92 )       $ (1.53 )
               
       
 
Unaudited pro forma weighted average shares outstanding—basic and diluted                 10,718           15,550  
               
       
 
 
  As of December 31,
   
 
 
  As of
March 31,
2004

 
 
  2001
  2002
  2003
 
 
  (In thousands)

 
Balance Sheet Data:                          
Cash and cash equivalents   $ 181   $ 1,471   $ 4,613   $ 16,585  
Short-term investments             7,994     14,615  
Working capital     (128 )   633     13,044     31,223  
Total assets     184     2,500     16,084     34,516  
Line of credit obligation—net of current portion             372     289  
Redeemable convertible preferred stock     22     6,427     27,225     48,432  
Accumulated deficit     (396 )   (5,785 )   (15,629 )   (39,417 )
Total stockholders' deficit     (148 )   (4,831 )   (13,779 )   (16,728 )

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MANAGEMENT'S DISCUSSION AND ANALYSIS OF
FINANCIAL CONDITION AND RESULTS OF OPERATIONS

         The following discussion and analysis of financial condition and results of operations should be read together with "Selected Financial and Operating Data," and our financial statements and accompanying notes appearing elsewhere in this prospectus. This discussion contains forward-looking statements, based on current expectations and related to future events and our future financial performance, that involve risks and uncertainties. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of many important factors, including those set forth under "Risk Factors" and elsewhere in this prospectus.

Overview

        Momenta is a biotechnology company specializing in the sequencing and engineering of complex sugars for the development of improved versions of existing drugs, the development of novel drugs and the discovery of new biological processes. We are also utilizing our ability to sequence sugars to create near-term technology-enabled generic products. Our most advanced product candidate, M-Enoxaparin, is designed to be a generic version of Lovenox, the most widely prescribed LMWH in the world. We have formed a collaboration with Sandoz to jointly develop, manufacture and commercialize M-Enoxaparin.

        Our revenues for the three months ended March 31, 2004 and the year ended December 31, 2003 were $1.0 million and $1.5 million, respectively, consisting of amortization of the initial payment due under our collaboration with Sandoz and amounts payable to us by Sandoz for reimbursement of research and development services and reimbursement of development costs for M-Enoxaparin. As a result of our collaboration with Sandoz, we ceased to be considered a development-stage company for financial statement reporting purposes in 2003. We have had no other revenue since inception other than interest on short-term investments.

        We commenced operations in May 2001. Since our inception, we have incurred annual net losses. As of March 31, 2004, we had an accumulated deficit of $39.4 million. We recognized net losses of $2.6 million for the first quarter of 2004, $7.9 million for Fiscal 2003 and $4.9 million for Fiscal 2002. We expect to incur substantial and increasing losses for the next several years as we develop our product candidates, expand our research and development activities and prepare for the commercial launch of our product candidates. Additionally, we plan to continue to evaluate possible acquisitions or licensing of rights to additional technologies, products or assets that fit within our growth strategy. Accordingly, we will need to generate significant revenues to achieve and then maintain profitability.

        Since our inception, we have had no revenues from product sales and have funded our operations primarily through the private placement of equity securities. In February 2004, we raised net cash proceeds of $20.4 million from the sale of Series C redeemable convertible preferred stock. Through March 31, 2004, we have raised net cash proceeds of $45.4 million through the private placement of redeemable convertible preferred stock. We have devoted substantially all of our capital resources to the research and development of our product candidates.

        The biotechnology and pharmaceutical industries in which we intend to compete are undergoing, and are expected to continue to undergo, rapid and significant technological change. We expect competition to intensify as technological advances are made or new biotechnology products are introduced, such as alternatives to LMWHs or improved non-invasive delivery methods. To become and remain profitable, we must succeed in developing and commercializing drugs with significant market potential. This will require us to be successful in a range of challenging activities for which we are only in the preliminary stages: developing drugs, obtaining regulatory approval for them, and manufacturing, marketing and selling them. We have invested a significant portion of our time, financial resources and collaboration efforts in the development of our most advanced product candidate, M-Enoxaparin. Our

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successful development and commercialization of M-Enoxaparin in collaboration with Sandoz will depend on several factors, including: using our technology to meet FDA criteria to demonstrate that M-Enoxaparin is therapeutically equivalent to Lovenox; scaling-up and manufacturing M-Enoxaparin for FDA approval and commercialization; and marketing M-Enoxaparin and achieving acceptance of M-Enoxaparin in the medical community and with third-party payors.

Financial Operations Overview

Revenue

        We have not yet generated any revenue from product sales and do not expect to generate any revenue from the sale of products over the next several years. We have recognized, in the aggregate, $2.5 million of revenue from our inception through March 31, 2004. This revenue was derived entirely from our collaboration agreement with Sandoz. We will seek to generate revenue from a combination of research and development payments, profit sharing payments, milestone payments and royalties in connection with our Sandoz collaboration and similar future collaborative or strategic relationships. We expect that any revenue we generate will fluctuate from quarter to quarter as a result of the timing and amount of research and development and other payments received under our collaborative or strategic relationships, and the amount and timing of payments we receive upon the sale of our products, to the extent any are successfully commercialized.

Research and Development

        Research and development expenses consist of costs incurred in identifying, developing and testing product candidates. These expenses consist primarily of salaries and related expenses for personnel, license fees, consulting, contract research and manufacturing, and the costs of laboratory equipment and facilities. We expense research and development costs as incurred.

        The following summarizes our primary research and development programs.

        M-Enoxaparin.     Our most advanced product, M-Enoxaparin, is designed to be a technology-enabled generic version of Lovenox. We have formed a collaboration with Sandoz to jointly develop, manufacture and commercialize M-Enoxaparin. Under our collaboration agreement, Sandoz is responsible for funding substantially all of the M-Enoxaparin development, regulatory, legal and commercialization costs. The total cost of development and commercialization and the timing of bringing M-Enoxaparin to market is subject to uncertainties relating to the development, regulatory approval and legal processes.

        M118.     M118 is a LMWH that was rationally designed to provide improved anti-clotting activity and flexible administration to treat patients with ACS. M118 is currently in preclinical development. We expect that additional expenditures will be required to complete preclinical testing and, if such preclinical testing is successful, we intend to file an IND and begin Phase I clinical trials shortly thereafter. Because M118 is in preclinical development, we are unable to estimate the cost to complete the research and development phase nor are we able to estimate the timing of bringing M118 to market.

        Other Development Opportunities.     Other research programs include: applying a sugar-mediated technology to improve the non-invasive delivery of therapeutic proteins and applying capabilities which enable engineering of complex sugars on therapeutic proteins to improve the efficacy, reduce side effects and modify the dosage of protein drugs. In our drug discovery program, we are applying our understanding of sugar biology to develop sugar-based drugs and identify specific biological processes and pathways that can be targeted with small molecules and antibody drugs, focused initially on oncology.

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General and Administrative

        General and administrative expenses consist primarily of salaries and other related costs for personnel in executive, finance, accounting, business development and human resource functions. Other costs include facility costs not otherwise included in research and development expense and professional fees for legal and accounting services.

        After this offering, we anticipate increases in general and administrative expense for investor relations and other activities associated with operating as a publicly-traded company. These increases will also likely include the hiring of additional personnel. We intend to continue to incur increased internal and external business development costs to support our various product development efforts, which can vary from period to period.

Sandoz Collaboration

        In November 2003, we entered into an exclusive collaboration and license agreement with Sandoz to jointly develop and commercialize M-Enoxaparin in the United States. For 2003, we were owed an initial payment of $0.6 million for reimbursement of specified development costs incurred prior to entering into the agreement, and $1.4 million for research and development services and other reimburseable costs incurred since the agreement commenced. The amount receivable of $2.0 million was billed and collected in full in 2004. The revenue from the initial payment is being recognized over the remaining life of the research and development program, which is estimated to be four years. We may receive additional research and development funding through product approval and launch, milestone payments and profit sharing payments or royalties on any product sales.

Results of Operations

Three Months Ended March 31, 2004 and 2003

Revenue

        Revenue for the first quarter of 2004 was $1.0 million, which was attributable to our collaboration agreement with Sandoz signed in November 2003. This revenue includes $36,789 in amortization of an initial payment made to us by Sandoz and $1.0 million payable to us for research and development services and other reimbursable costs. We had zero revenues in the first quarter of 2003.

Research and Development

        The following table summarizes the primary components of our research and development expense for our principal research and development programs for the three months ended March 31, 2003 and 2004.

Research and Development Program

  2003
  2004
M-Enoxaparin   $ 526,426   $ 708,151
M118     44,592     787,224
Drug delivery     91,011     346,742
Other discovery and development programs     128,114     397,653
   
 
Total research and development expense   $ 790,143   $ 2,239,770
   
 

        Research and development expense for the first quarter of 2004 was $2.2 million compared to $0.8 million in the first quarter of 2003. Our increase in research and development expenses principally resulted from an increase of $0.7 million in the M118 program in the first quarter of 2004 due to an increase of $0.5 million in contracted manufacturing costs as we commenced the manufacturing of pre-clinical product, an increase of $0.3 million in our drug delivery program due to increased staffing

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and related expenses, and an increase of $0.2 million of expenses associated with the M-Enoxaparin program, primarily reflecting an increase in staffing and related expenses as a result of our collaboration with Sandoz. In addition, costs increased in our drug delivery and other discovery and development programs primarily due to increases in staffing and related expenses due to increased headcount.

General and Administrative

        General and administrative expense for the first quarter of 2004 was $1.4 million compared to $0.7 million in the first quarter of 2003. General and administrative expense increased due to an increase of $0.2 million in stock compensation expense, an increase of $0.2 million in consulting and professional fees, an increase of $0.1 million in personnel and related costs due to increased headcount, and an increase of $0.1 million in legal costs due to an increase in corporate and patent-related legal services.

Interest Income and Expense

        Interest income increased to $41,635 in the first quarter of 2004 from $3,808 in the first quarter of 2003, primarily due to higher average investment balances in 2004 as a result of the proceeds from our issuance of Series B preferred stock in May 2003 and Series C preferred stock in February 2004. Interest expense increased from the first quarter of 2003 to the first quarter of 2004 due to a higher average balance on our bank line of credit in 2004.

Years Ended December 31, 2003, 2002 and the Period from Inception (May 17, 2001) to December 31, 2001

Revenue

        Revenue for Fiscal 2003 was $1.5 million, which was attributable to our collaboration agreement with Sandoz signed in November 2003. This revenue includes $24,526 in amortization of an initial payment made to us by Sandoz and $1.4 million payable to us for research and development services and other reimbursable costs. We had zero revenues in Fiscal 2002 and 2001.

Research and Development

        Research and development expense for Fiscal 2003 was $5.3 million compared to $2.2 million in Fiscal 2002 and $0.2 million in Fiscal 2001. In Fiscal 2003 compared with Fiscal 2002, our increased research and development expense principally resulted from an increase of $3.0 million of expenses associated with the M-Enoxaparin program, reflecting an increase of $1.2 million in personnel and related costs and an increase of $1.6 million in contracted costs for manufacturing process development, and the initiation of the M118 program in 2003. In Fiscal 2002 compared to Fiscal 2001, research and development expenses increased primarily due to the growth of our operations in 2002. In addition, Fiscal 2002 include charges totaling $0.6 million for license fees.

        The following table summarizes the primary components of our research and development expense for our principal research and development programs for Fiscal 2001, 2002 and 2003.

Research and Development Program

  2001
  2002
  2003
M-Enoxaparin   $   $ 960,719   $ 3,927,826
M118             541,654
Other discovery and development programs     206,437     1,212,920     878,365
   
 
 
Total research and development expense   $ 206,437   $ 2,173,639   $ 5,347,845
   
 
 

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General and Administrative

        General and administrative expense for Fiscal 2003 was $4.1 million compared to $2.7 million in Fiscal 2002 and $0.2 million Fiscal 2001. In Fiscal 2003 compared to Fiscal 2002, general and administrative expense increased due to an increase of $0.3 million in stock compensation expense, an increase of $0.8 million in personnel costs due to increased headcount and an increase of $0.3 million in legal costs due to an increase in corporate and patent-related legal services. General and administrative expenses increased in Fiscal 2002 compared to Fiscal 2001 primarily due to our limited scope of operations in 2001.

Interest Income

        Interest income increased to $73,969 in Fiscal 2003 from $16,965 in Fiscal 2002, primarily due to higher average investment balances as a result of the proceeds from our issuance of Series B preferred stock in May 2003. Interest income increased from Fiscal 2001 to Fiscal 2002 due to our Series A Prime and Series A Double Prime financings.

Interest Expense

        Interest expense of $42,920 in Fiscal 2003 related to amounts drawn from our bank line of credit. There were zero borrowings and zero interest expense in Fiscal 2001 and 2002.

Liquidity and Capital Resources

        We have financed our operations since inception primarily through the private placement of equity securities. As of March 31, 2004, we have received net proceeds of $45.4 million from the issuance of redeemable convertible preferred stock. At March 31, 2004, we had $31.2 million in cash, cash equivalents and short-term investments. In February 2004, we sold 2,612,696 shares of our Series C redeemable convertible preferred stock for net proceeds of $20.4 million to existing preferred stockholders and one new investor. These shares contain a beneficial conversion feature based on the fair value of our common stock at the date of such sale compared to the Series C redeemable convertible preferred stock share price. For financial accounting purposes, the total value of the beneficial conversion feature of approximately $20.4 million was recognized as a dividend in the first quarter of 2004.

        Net cash used in operating activities was $1.7 million for the first quarter of 2004, $1.4 million for the first quarter 2003, $8.0 million for Fiscal 2003, $3.7 million for Fiscal 2002, and $45,547 for Fiscal 2001. The use of cash in each period was primarily a result of net losses associated with our research and development activities and amounts incurred to develop our administrative infrastructure.

        Net cash used in investing activities was $6.7 million for the first quarter of 2004, $0.1 million for the first quarter of 2003, $8.5 million for Fiscal 2003 and $0.9 million for Fiscal 2002. In the first quarter of 2004, we used $7.4 million of cash to purchase short-term investments and had $0.8 million in maturities of short-term investments. In the first quarter of 2003, we used $0.1 million to purchase equipment. We used $8.0 million of cash in 2003 to purchase short-term investments and used $0.5 million and $0.9 million in 2003 and 2002, respectively, to purchase equipment and leasehold improvements. We expect approximately $2.0 million in capital expenditures for 2004, principally related to the purchase of laboratory equipment and leasehold improvements.

        In the first quarter of 2004, our financing activities provided $20.3 million, reflecting the issuance of our Series C redeemable convertible preferred stock for net proceeds of $20.4 million. In the first quarter of 2003, $0.9 million was provided by financing activities, primarily $0.9 million from drawing on a bank line of credit. Net cash provided by financing activities was $19.7 million for Fiscal 2003, $5.9 million for Fiscal 2002 and $0.2 million for Fiscal 2001. Cash provided for 2003 primarily reflects

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the issuance of 6,440,678 shares of Series B redeemable convertible preferred stock resulting in net cash proceeds of $18.9 million and proceeds from a line of credit obligation of $1.0 million, offset by lease payments of $0.3 million. Cash provided in Fiscal 2002 and 2001 primarily reflects the proceeds from the issuance of Series A redeemable convertible preferred stock.

        The following table summarizes our contractual obligations at December 31, 2003 and the effects such obligations are expected to have on our liquidity and cash flows in future periods.

Payments Due by Period

Contractual Obligations

  Total
  2004
  2005 through 2006
  2007 through 2008
  After 2008
License maintenance obligations(1)   $ 502,500   $ 67,500   $ 205,000   $ 230,000      
Short and long-term line of credit obligation     713,229     329,996     383,233       $
Operating lease obligations     348,464     342,021     5,970     473    
   
 
 
 
 
Total contractual cash obligations(2)(3)   $ 1,564,193   $ 739,517   $ 594,203   $ 230,473   $
   
 
 
 
 

(1)
After 2008, the annual obligations, which extend indefinitely, range from $182,000 to $217,500 per year.

(2)
We have signed a non-binding letter of intent with a third party to enter into a ten year lease for office and laboratory space which, if entered into upon the same terms as the letter of intent, would add the following amounts to our operating lease obligations: 2004: $321,332; 2005 through 2006: $2,059,767; 2007 through 2008: $2,345,843; after 2008: $7,496,478.

(3)
In May 2004, we amended an agreement with a third party to provide up to an additional $1.6 million of process development and production work, for a total remaining cash obligation of up to $2.0 million, which we expect to pay in 2004 and 2005.

        We anticipate that our current cash, cash equivalents and short-term investments, including $20.4 million in net proceeds received in connection with the issuance of our Series C convertible preferred stock in February 2004, and the expected net proceeds from this offering will be sufficient to fund our operations for at least 36 months. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially.

Funding Requirements

        We have received $2.0 million as of March 31, 2004 from our collaboration with Sandoz. We did not receive payments from any collaborations from our inception through December 31, 2003. Under our collaboration with Sandoz, Sandoz has agreed to fund a minimum amount of personnel and substantially all of the other ongoing development, commercialization and legal expenses incurred with respect to our M-Enoxaparin program, subject to the right to terminate upon reaching an agreed-upon limit.

        We expect to use the net proceeds from this offering to continue the development of our product candidates, our discovery research programs and for other general corporate purposes. We intend to use the majority of the net proceeds to fund:

    the approval and subsequent commercialization of near-term product candidates, including approximately $8.0 million to $10.0 million to develop M-Dalteparin through the filing of an ANDA; and

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    the development of improved product candidates, including using approximately $15.0 million to $20.0 million to develop M118 through Phase I and Phase II clinical trials and $15.0 million to $20.0 million for the initial development of pulmonary formulations of therapeutic proteins.

        We anticipate using the remaining net proceeds of this offering to fund:

    the research and discovery of novel therapeutics and technologies; and

    working capital, capital expenditures and other general corporate purposes.

        In addition, we may also use a portion of the proceeds for the acquisition of, or investment in, companies, technologies, products or assets that complement our business. However, we have no present understandings, commitments or agreements to enter into any potential acquisitions or investments.

        We expect to incur substantial costs and losses as we continue to expand our research and development activities, particularly as we progress M118 into Phase I clinical trials. Our funding requirements will depend on numerous factors, including:

    the progress of development of M-Enoxaparin, M-Dalteparin and M118;

    the timing, receipt and amount of milestone and other payments, if any, from present and future collaborators;

    the time and costs involved in obtaining regulatory approvals;

    the continued progress in our research and development programs, including completion of our preclinical studies and clinical trials;

    the costs involved in preparing, filing, prosecuting, maintaining and enforcing patent claims;

    the potential acquisition and in-licensing of other technologies, products or assets;

    the timing, receipt and amount of sales and royalties, if any, from our product candidates;

    the cost of manufacturing, marketing and sales activities, if any; and

    the cost of litigation, including potential patent litigation.

        We do not expect to generate significant additional revenues, other than payments that we receive from our collaboration with Sandoz or other similar future collaborations, until we successfully obtain marketing approval for, and begin selling, M-Enoxaparin. We believe the key factors that will affect our internal and external sources of cash are:

    our ability to successfully develop, manufacture, obtain regulatory approval for and commercialize M-Enoxaparin;

    the success of M118 and other preclinical and clinical development programs;

    the receptivity of the capital markets to financings by biotechnology companies; and

    our ability to enter into additional strategic collaborations with corporate and academic collaborators and the success of such collaborations.

        If our existing resources and the proceeds of this offering are insufficient to satisfy our liquidity requirements or if we acquire or license additional technologies, products or assets that fit within our growth strategy, we may need to raise additional external funds through the sale of equity or debt securities. The sale of equity securities may result in dilution to our stockholders. Additional financing may not be available in amounts or on terms acceptable to us or at all. If we are unable to obtain additional financing, we may be required to reduce the scope of, delay or eliminate some or all of our

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planned research, development and commercialization activities, which could harm our financial condition and operating results.

Critical Accounting Policies and Estimates

        Our discussion and analysis of our financial condition and results of operations are based on our financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. On an on-going basis, we evaluate our estimates and judgments, including those related to revenue, accrued expenses and the fair valuation assigned to our common stock. We base our estimates on historical experience, known trends and events and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

        We believe the following critical accounting policies affect our more significant judgments and estimates used in the preparation of our financial statements.

Revenue

        We record revenue on an accrual basis as it is earned and when amounts are considered collectible. Revenues received in advance of performance obligations or in cases where we have a continuing obligation to perform services are deferred and recognized over the performance period. Revenues from milestone payments that represent the culmination of a separate earnings process are recorded when the milestone is achieved. Contract revenues are recorded as the services are performed. When we are required to defer revenue, the period over which such revenue should be recognized is subject to estimates by management and may change over the course of the collaborative agreement.

Accrued Expenses

        As part of the process of preparing financial statements, we are required to estimate accrued expenses. This process involves identifying services which have been performed on our behalf, and estimating the level of service performed and the associated cost incurred for such service as of each balance sheet date in our financial statements. Examples of estimated expenses for which we accrue include contract service fees paid to contract manufacturers in conjunction with the production of clinical drug supplies and to contract research organizations. In connection with such service fees, our estimates are most affected by our understanding of the status and timing of services provided relative to the actual levels of services incurred by such service providers. The majority of our service providers invoice us monthly in arrears for services performed. In the event that we do not identify certain costs, which have begun to be incurred, or we under- or over-estimate the level of services performed or the costs of such services, our reported expenses for such period would be too low or too high. The date on which certain services commence, the level of services performed on or before a given date and the cost of such services are often determined based on subjective judgments. We make these judgments based upon the facts and circumstances known to us in accordance with generally accepted accounting principles.

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Stock-Based Compensation

        We have elected to follow Accounting Principles Board Opinion No. 25, Accounting for Stock Issued to Employees , or APB 25, and related interpretations, in accounting for our stock-based compensation plans, rather than the alternative fair value method provided for under Statement of Financial Accounting Standard No. 123, or SFAS 123, Accounting for Stock-Based Compensation . In 2002 and 2003, certain grants of stock options were made at exercise prices less than the fair value of our common stock and, as a result, we recorded deferred stock compensation expense. In the notes to our financial statements, we provide pro forma disclosures in accordance with SFAS 123. We account for transactions in which services are received from non-employees in exchange for equity instruments based on the fair value of such services received or of the equity instruments issued, whichever is more reliably measured, in accordance with SFAS 123 and the Emerging Issues Task Force, or EITF, Issue 96-18, Accounting for Equity Instruments that Are Issued to Other than Employees for Acquiring, or in Conjunction with Selling, Goods or Services , or EITF 96-18.

        Accounting for equity instruments granted or sold by us under APB 25, SFAS 123 and EITF 96-18 requires fair value estimates of the equity instrument granted or sold. If our estimates of the fair value of these equity instruments are too high or too low, our expenses may be over or under stated. Equity instruments granted or sold in exchange for the receipt of goods or services and the value of those goods or services cannot be readily estimated, as is true in connection with most stock options and warrants granted to employees and non-employees. We estimated the fair value of the equity instruments based upon consideration of factors which we deemed to be relevant at the time. Because shares of our common stock have not been publicly traded, market factors historically considered in valuing stock and stock option grants include comparative values of public companies discounted for the risk and limited liquidity provided for in the shares we are issuing, pricing of private sales of our redeemable convertible preferred stock, prior valuations of stock grants and the effect of events that have occurred between the time of such grants, economic trends, and the comparative rights and preferences of the security being granted compared to the rights and preferences of our other outstanding equity.

        The fair value of our common stock is determined by our board of directors. In the absence of a public trading market for our common stock, our board of directors considers objective and subjective factors in determining the fair value of our common stock. At the time of option grants and other stock issuances, our board of directors considered the liquidation preferences, dividend rights and voting control attributable to our then-outstanding redeemable convertible preferred stock and, primarily, the likelihood of achieving a liquidity event such as an initial public offering or sale of Momenta.

Recently Issued Accounting Pronouncements

        In January 2003, the FASB issued Financial Interpretation Number 46, Consolidation of Variable Interest Entities (FIN 46). This interpretation requires existing unconsolidated variable interest entities to be consolidated by their primary beneficiaries if the entities do not effectively disperse risks among parties involved. It explains how to identify variable interest entities and how an enterprise assesses its interest in a variable interest entity to decide whether to consolidate that entity. This interpretation, as amended, applies in the first fiscal year or interim period beginning after December 15, 2003, to variable interest entities in which an enterprise holds a variable interest that it acquired before February 1, 2003. Since we do not currently have any unconsolidated variable interest entities, we do not expect the adoption of FIN 46 to have a material impact on our financial position or results of operations.

        In May 2003, the FASB issued SFAS No. 150, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity. This statement establishes how a company classifies and measures certain financial instruments with characteristics of both liabilities and equity, including

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redeemable preferred stock. This statement is effective for financial instruments entered into or modified after May 31, 2003, and otherwise effective at the beginning of the interim period commencing July 1, 2003, except for mandatory redeemable financial instruments of nonpublic companies, which is effective for fiscal periods beginning after December 31, 2004. We do not expect the adoption of this statement will have a material impact on its financial statements.

Quantitative and Qualitative Disclosures about Market Risk

        We are exposed to market risk related to changes in interest rates. Our current investment policy is to maintain an investment portfolio consisting mainly of U.S. money market and high-grade corporate securities, directly or through managed funds, with maturities of eighteen months or less. Our cash is deposited in and invested through highly rated financial institutions in North America. Our marketable securities are subject to interest rate risk and will fall in value if market interest rates increase. If market interest rates were to increase immediately and uniformly by 10% from levels at March 31, 2004, we estimate that the fair value of our investment portfolio would decline by an immaterial amount. While our cash and investment balances will increase upon completion of the offering contemplated by this prospectus, we will have the ability to hold our fixed income investments until maturity, and therefore we would not expect our operating results or cash flows to be affected to any significant degree by the effect of a change in market interest rates on our investments.

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BUSINESS

Overview

        Momenta is a biotechnology company specializing in the detailed structural analysis and design of complex sugars for the development of improved versions of existing drugs, the development of novel drugs and the discovery of new biological processes. We are also utilizing our ability to sequence sugars to create technology-enabled generic products. Through detailed analysis of the molecular structure of complex sugars, our proprietary technology provides a more complete understanding of the roles that sugars play in cellular function, disease and drug action. Based on our understanding of complex sugars, we have developed a diversified pipeline of novel discovery and development candidates and near-term product opportunities. Our business strategy is to utilize near-term product opportunities to provide a funding source for our discovery and development programs. Over the long term, we expect to generate value by leveraging our understanding of sugars to create novel therapeutics which address critical unmet medical needs in a wide range of disease areas including oncology, cardiovascular disease, inflammation and immunology.

        Our most advanced product candidate, M-Enoxaparin, is designed to be a technology-enabled generic version of Lovenox, a LMWH, used to prevent and treat DVT, and treat ACS. Aventis reported worldwide sales of Lovenox to be approximately $1.9 billion in 2003, and analysts project sales to exceed $3.0 billion in 2008. The development of M-Enoxaparin is enabled by our ability to analyze sugars. We believe it will be difficult for others to perform similar analyses. We have formed a collaboration with Sandoz to jointly develop, manufacture and commercialize M-Enoxaparin. In addition, we intend to develop a technology-enabled generic version of Fragmin, another LMWH. Currently, there are no FDA approved generic equivalents of Lovenox or Fragmin.

        We intend to use our technology to improve existing drugs and develop novel drugs. Our novel development opportunities include:

        Our drug discovery program, which is focused initially in oncology, is designed to leverage our understanding of sugar biology. We believe that we will be able to use this understanding to develop sugar-based drugs and identify specific biological processes and pathways that can be targeted with small molecule or antibody drugs.

Background on Sugars

Overview

        The ability to sequence DNA and proteins enabled the first biotechnology companies to develop breakthrough products. Recent scientific studies have demonstrated that sugars also play fundamental roles in the regulation of biological activity and, consequently, in the cause and treatment of many diseases as well as in drug action. Sugars, together with DNA and proteins, are critical molecules that regulate biological processes and pathways in the human body. Due to the complex molecular structures of sugars and the lack of sophisticated analytical tools and methods required to examine the minute quantities of sugars that occur in nature, sugars have not been well defined or their molecular structures determined. Without being able to identify specific structures, it is not presently possible to monitor how these sugars act in biological organisms. As a consequence, the development of sugar-based drugs to date has been through more of a "trial-and-error" approach. We believe understanding

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the structure, specific function and manner in which complex sugars affect critical biological processes and pathways will provide significant commercial opportunities for drug discovery and development.

        Complex sugars influence fundamental biological processes and pathways, disease onset and progression and drug action. The manner in which a cell produces sugars is critical for normal cell function and communication. Importantly, malfunctions in complex sugar production and the resulting abnormalities in sugar structures have been shown to play a fundamental role in numerous major diseases, such as cancer, cardiovascular disease, inflammatory disease and viral infection.

Biology of Complex Sugars

        Complex sugars exist within, on the surface of and between cells, where they are attached to proteins, lipids, and other biologic molecules. In selected cases, complex sugars exist alone and unattached. Structurally, complex sugars are composed of individual saccharide building blocks, or monosaccharides, that may form linear or branched chains.

        The location of the complex sugar determines the distinct function that it performs:


Applications of Complex Sugars in Drug Discovery and Development

        Understanding where sugars are found in the body, as well as their role in selected therapeutics, creates opportunities for complex sugar-based drug discovery and development. In general, there are four major ways in which the knowledge of complex sugars can be applied to develop drugs:

        Complex sugar-based therapeutics.     Complex sugars, either synthesized chemically or isolated from natural sources, can be used as therapeutic drugs. One prominent example is the heparin class of sugars, which exist as heterogeneous mixtures of complex sugar chains extracted from the lining of pig intestines. Heparins are used therapeutically to prevent blood clotting and represented approximately a $2.8 billion worldwide market in 2002. Other complex sugar-based drugs in development include chondroitins for neural injury and pectins for cancer.

        Engineering sugars on therapeutics.     There are three major drug classes that frequently have complex sugar coats: proteins (including antibodies), vaccines and antibiotics. Therapeutic proteins, the vast majority of which contain sugar coats, are a rapidly growing area of the pharmaceutical and biotechnology industries. Worldwide annual sales of therapeutic proteins are estimated to be

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$30.3 billion. Altering the complex sugar coat of a protein can dramatically change the properties of a drug. For example, Amgen, Inc. modified its protein drug, Epogen®, by incorporating additional sugar groups to the protein creating a novel second generation anemia drug, Aranesp®, that has a decreased dosing schedule.

        Complex sugars in small molecule and antibody development.     The fields of genomics and proteomics have resulted in the identification of large numbers of genes and proteins. Understanding only DNA and proteins, however, provides incomplete information about the biological function of these potential drug targets. Identifying appropriate drug targets depends on understanding the sequential interaction of proteins in disease, known as disease pathways. Understanding the role of sugars, which can both activate and regulate these pathways, provides a more complete picture of biology and we believe can create critical new insights for drug discovery.

        Complex sugars as diagnostic and prognostic measures of disease.     Complex sugar patterns on proteins and cells can be used to diagnose disease, and we believe can enable a more accurate determination of the stage of disease and improve disease management. Diseases, such as cancer or inflammation, cause fundamental changes in affected cells, which in turn cause changes in complex sugar structures. These changes in sugars are often detectible earlier in the disease process than are elevations in protein levels, which have been previously used as markers for disease detection. By detecting changes in the sugar patterns, it may be possible to more accurately diagnose disease and determine disease severity with greater sensitivity than conventional protein-based markers.

Challenges to Developing Drugs Based on Complex Sugars

        A number of challenges have inhibited the widespread analysis and application of complex sugars to drug development:

        Structural complexity and information density.     Deciphering the role of complex sugars in promoting or treating human diseases has been challenging given the density of information contained in complex sugars and the lack of sophisticated tools to interpret their information content. Complex sugars have far more information density than DNA and proteins. DNA is comprised of four different bases and proteins can contain 20 different amino acids. The DNA bases and amino acids can be combined to produce 256 possible four-unit DNA structures and 160,000 potential four-unit protein structures, respectively. In comparison, complex sugars, such as heparin, may contain as many as 48 different disaccharide units, resulting in approximately 5.3 million possible four-unit disaccharide combinations. In addition, while proteins and DNA exist only in linear forms, sugars can also exist in branched forms, adding structural complexity and information density.

        Lack of amplification.     DNA and proteins can be easily amplified, or duplicated, in larger quantities for analysis, facilitating simple manipulation and rapid identification of sequences. Complex sugars, however, cannot be amplified due to their structural diversity and the manner in which they are synthesized. Consequently, the analysis of complex sugars requires the development of novel, highly sensitive, analytical tools and technologies that can work with small quantities of material.

        Heterogeneity.     DNA and proteins can be isolated and therefore, studied in pure or homogeneous forms, permitting straightforward analysis. In contrast, most complex sugars exist as heterogeneous mixtures of sugar chains. Current technologies are unable to adequately separate mixtures of sugar chains into individual sugar chains and sequence specific chains or individual saccharide building blocks.

        These limitations have made sugar-based drug research, discovery and development challenging, leading the National Institutes of Health, or NIH, to identify the study of sugars as a key field expected to shape the future of molecular and cellular biology and to devote significant financial resources to create the Consortium for Functional Glycomics.

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Momenta Technology Solution

        We have developed an integrated technology solution that addresses the challenges of creating drugs based on complex sugars. Our technology enables rapid, precise and comprehensive sequencing of complex sugars. Using proprietary enzymes or reagents, we break down structurally complex and information dense sugar chains, including those contained in complex mixtures, into measurable units. Our proprietary analytical techniques and expertise allow us to gather information regarding the components, structure and arrangement of the building blocks in the sugar chains. Our proprietary mathematical methods allow us to integrate the information we obtain from multiple sources into a specific, numerically derived solution describing the specific sugar sequence. The combined sensitivity of all of our analytical techniques allows us to work with very small quantities of material, avoiding the need for amplification.

        The specific elements that make up our proprietary technology include the following:

        Our proprietary technology has enabled us to rapidly sequence and accurately verify complex sugars in a matter of minutes to hours—a process which previously took years. We apply our various proprietary techniques to a specific complex sugar sample to yield distinct structural information including the sample's molecular weight, composition of its saccharide units, specific linkages and other characteristics. For example, we believe we were the first to rapidly and accurately sequence complex sugar chains comprised of ten saccharide units, which can contain up to 255 million possible combinations. Our approach is to first measure the mass of the sugar using our proprietary MALDI-MS techniques. Through this mass analysis, we can determine the chain length and certain chemical structures of the sugar chain. We utilize various proprietary enzymes to break the sugar chain into smaller units to determine the sequence order of sugar building blocks. We can also apply our proprietary approaches to NMR to ascertain information about the manner in which various sugar building blocks are linked to one another. The various sources of data are integrated using our proprietary mathematical methods, thereby enabling a precise characterization, or sequencing, of the complete structure of a complex sugar chain.

        Our technology has the following features:

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Applications of Momenta Technology

        We plan to apply our technology to product development in three primary ways:

        Enable generic versions of complex drugs through characterization.     Many currently marketed drugs containing sugars have not been fully characterized, or sequenced, due to lack of available technology. These drugs include heparins, therapeutic proteins, vaccines and antibiotics. Our technology allows us to elucidate the precise sugar sequences contained in marketed, complex sugar-based drugs, including those structures that had not previously been described. To approve generic versions of branded products, the FDA requires data demonstrating that the generic product contains the same active ingredients as the branded product. The inability to analyze existing complex sugar-based drugs has made it difficult to obtain approval of generic versions of such drugs to date. We believe that the information obtained from our detailed analysis can be applied to develop technology-enabled generic versions of complex sugar-based marketed products.

        Improve therapeutic products.     We intend to use our technology to create proprietary drugs that represent improvements over currently marketed drugs by:


        Discover novel drugs.     We intend to apply our understanding of the role sugars play in basic biology and in disease onset, progression and treatment to develop novel, sugar-based, small molecule and antibody drugs. Research has shown that malfunctions in sugar production and the resulting abnormal sugar structures play a fundamental role in diseases, including cancer, cardiovascular disease, Alzheimer's disease, inflammatory disease and viral infection. Our current focus on drug discovery is in

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oncology, where we believe we can apply our technology to develop drugs that act through novel mechanisms. Based on our recent research, we have shown that sugars can both decrease the growth and increase the death of cancer cells.

Our Business Strategy

        Our objective is to become a leading biotechnology company by applying our understanding of complex sugars and our proprietary technologies to drug discovery, development and commercialization. The key elements of our strategy are to:

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Product Pipeline

Overview of Product Pipeline

        Our product pipeline consists of technology-enabled generic versions of marketed, complex, sugar-based drugs, new compounds that are improved versions of existing products and novel discovery candidates. The pipeline is summarized in the table below:

Drug Candidate(s)

  Therapeutic Area
  Current Stage of
Development

M-Enoxaparin*   Thrombosis   Pre-ANDA
M-Dalteparin   Thrombosis   Development
M118   Cardiovascular Disease   Preclinical
Pulmonary Insulin   Diabetes   Preclinical
Pulmonary HGH   Growth Hormone Deficiency   Preclinical
Pulmonary Interferon-beta   Multiple Sclerosis   Discovery
Pulmonary Erythropoietin   Anemia   Discovery
Sugar Therapeutic   Oncology   Discovery

*
In collaboration with Sandoz

Near-Term Product Opportunities

        Our most advanced product candidate, M-Enoxaparin, which is enabled by our technology and understanding of complex sugars, is designed to be a generic version of Lovenox. Lovenox is distributed worldwide by Aventis and is also known outside the United States as Clexane® and Klexane®. Lovenox is the most widely-prescribed LMWH in the world used for the prevention and treatment of DVT and treatment of ACS. In 2003, Aventis reported worldwide sales of Lovenox of approximately $1.9 billion, and analysts project sales to exceed $3.0 billion in 2008. Lovenox is a heterogeneous mixture of complex sugar chains that has not been adequately analyzed to date. Aventis, in a Citizen Petition filed with the FDA in February 2003 and in a supplement filed in February 2004, requested, among other things, that the FDA refrain from approving any ANDA for a generic version of Lovenox until such time as Lovenox has been fully characterized. Our ability to sequence and analyze complex mixtures of sugars has allowed us to analyze Lovenox and develop a process that we believe can be used to make a generic version of Lovenox that will meet the FDA requirements for ANDA approval. We believe it will be difficult for others to perform similar analyses. We have formed a collaboration with Sandoz to jointly develop, manufacture and commercialize a generic version of Lovenox. We intend to file an ANDA, or other regulatory application as determined by the FDA, in the next 12 months.

        Market Overview.     DVT affects approximately 2.0 million people in the United States each year, approximately 600,000 of whom experience potentially fatal pulmonary embolisms. In addition, more than 20 million people in the United States annually undergo major surgeries or have restricted mobility due to medical illnesses, which place them at risk for DVT. Each year, approximately 1.3 million patients in the United States are also diagnosed with ACS. ACS includes several diseases from unstable angina, which is characterized by chest pain at rest, to acute myocardial infarction, or heart attack, which is caused by a complete blockage of a coronary artery. All diseases in ACS are associated with the formation of blood clots.

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        According to industry forecasts, the LMWH class of drugs is projected to grow from annual sales of $2.5 billion worldwide today to annual sales of over $3.6 billion by 2010. Lovenox is the leading LMWH product, with the broadest set of approved indications of any of the LMWHs currently marketed. Aventis reported worldwide sales of Lovenox of approximately $1.9 billion in 2003, with approximately $1.2 billion coming from the United States market alone. Fragmin (Pfizer) and Fraxiparine® (Sanofi-Synthelabo) are the next closest competitors to Lovenox. In 2002, worldwide sales of Fragmin were $270 million, and in 2003, worldwide sales of Fraxiparine were $361 million. Analysts project that Lovenox will remain the dominant LMWH product, growing to over $3.0 billion in annual sales by 2008, which represents over 83% of the estimated LMWH market.

        Aventis has publicly disclosed its plans to secure Lovenox's position as the leading injectable anticoagulant by seeking approval for additional indications in ACS, in which unfractionated heparin, or UFH, is currently the leading drug. In addition, Aventis is seeking to both grow existing and secure new indications for the prevention and treatment of DVT and pulmonary embolism. These new indications may lead to substantial sales growth, especially in the United States, where Lovenox currently dominates the LMWH market.

        Lovenox composition.     Lovenox is derived from UFH, which is a naturally occurring sugar mixture derived from the lining of pig intestines. UFH exists as a complex, heterogeneous mixture of sugar chains of varying length and varying sequence. Lovenox is made by chemically cutting these longer UFH chains into shorter chains, which are also heterogeneous with respect to length and sequence, resulting in a diversity of chemical structures in the mixture.

        The current description of Lovenox includes molecular weight distribution and in vitro measurements of Lovenox's ability to inhibit blood clotting factors Xa and IIa, or its anti-Xa and anti-IIa activity. Molecular weight distribution provides a rough measure of the range of chain lengths but provides no information about detailed sequences or chemical structures. The in vitro measures of anti-Xa and anti-IIa activity describe certain aspects of anticoagulation but only partially define the biological and clinical activity of Lovenox. According to Aventis, only 15% to 25% of the chains in LMWHs contain sequences that bind to the factor that is responsible for anti-Xa and anti-IIa activity. We believe our technology enables a detailed description of the Lovenox mixture.

        The need for detailed analysis of enoxaparin.     According to FDA regulations, a generic drug must have, among other requirements, the same active ingredients as the innovator or the "reference listed drug product" upon which the generic application is based. The FDA's definition of an active ingredient is "any component that is intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body of man or other animals."

        We believe the many sugar structures in Lovenox contribute to the drug's various biological activities and thus represent components of the active ingredients by the FDA's definition. There is significant evidence that specific structures contained in heparins, such as Lovenox, contribute to various biological activities beyond the current description of anticoagulation. Specifically, it has been shown in scientific literature that heparins bind to many biologically important factors. These structures are not described by molecular weight distribution or anti-Xa and anti-IIa activity measures. Through our technology, we have the ability to analyze the Lovenox mixture and demonstrate that a generic product has the same active ingredients as Lovenox.

        While Aventis publicly acknowledges that they have not characterized large portions of Lovenox, they have been able to analyze certain additional chemical features of the product. Through their analysis, Aventis has stated that it is possible to make an "alternative LMWH" that possesses the same molecular weight distribution and in vitro anti-Xa and anti-IIa activity as Lovenox, but contains different chemical structures, making it chemically distinct from Lovenox. They have shown that these chemical differences can result in changes in biological activities, which are relevant to the efficacy of

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the product. These changes impact biological processes that are important in clot formation and ACS, such as the growth of smooth muscles in blood vessels and the activity of factors, such as fibroblast growth factor, that can help to increase blood flow through growing new blood vessels. They have also shown that these structures can potentially affect anticoagulation parameters that are not measured by in vitro anti-Xa and anti-IIa activity alone and may affect both efficacy and bleeding risks associated with the product.

        Based on evidence that multiple structures in Lovenox contribute to its overall activity, we believe any regulatory application for generic enoxaparin must demonstrate that it has the same active ingredients as Lovenox, thereby enabling the FDA to approve the application. We believe this detailed analysis is required to assure the equivalent efficacy and safety of the generic product to Lovenox.

        M-Enoxaparin development strategy.     Through the application of our technology, we believe we will meet FDA requirements and, therefore, have our regulatory application for M-Enoxaparin approved. Under FDA guidelines, generic drugs are considered pharmaceutically equivalent to their branded counterparts if, among other things, they contain the same active ingredient(s), dosage form, route of administration and are identical in strength or concentration. To be therapeutically equivalent, a generic product must be pharmaceutically equivalent and be expected to have the same clinical effect and safety profile, thus making it typically interchangeable with the branded product; interchangeable products are denoted by an "A" rating by the FDA. Products with "A" ratings are generally substituted for the innovator drug by both in-hospital and retail pharmacies and many health insurance plans require automatic substitution of "A" rated generic versions when they are available.

        We plan to manufacture and provide the appropriate stability and reproducibility data on multiple batches of M-Enoxaparin and demonstrate that our proposed product has the same active ingredients and is therapeutically equivalent to Lovenox. Detailed information on the reproducibility and validation of our methodology, such as techniques and assays, will be presented to the FDA, in accordance with FDA regulations and requirements. In addition, all activities will be conducted in accordance with cGMP.

        To date, we have successfully accomplished the following:

        Prior to submitting a regulatory application, we intend to complete our scale up of the bulk drug substance, fill the drug substance into syringes and vials to create the final drug product presentations and test stability of the finished drug substance and product lots.

        Legal matters.     Currently, Aventis has listed two patents for Lovenox in the Orange Book, the FDA's listing of approved drug products. According to Aventis, United States Patent No. 4,692,435 expires December 24, 2004, which is prior to the date we anticipate we will commercialize M-Enoxaparin, and Patent No. 5,389,618, or the '618 patent, expires on February 14, 2012. We are currently evaluating our options with respect to the '618 patent.

        It is typical for the manufacturer of the branded product to initiate litigation against generic competitors seeking FDA approval to commercialize their products prior to expiration of the branded

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company's patents. Aventis has sued both Amphastar and Teva for patent infringement based upon their respective generic enoxaparin filings, and we anticipate Aventis may also initiate legal proceedings against us following our regulatory filing. There is also the possibility that other third party patent infringement claims will be brought against us. With certain exceptions, Sandoz will indemnify us for any losses we incur or must pay to a third party which result from patent infringement litigation by Aventis, and certain other claims, in each case which relate to the development and commercialization of our generic enoxaparin product. Sandoz may offset certain of these costs against the profit-sharing amounts, the royalties and the commercial milestone payments they may be required to make to us.

        We intend to develop a technology-enabled generic version of Fragmin (dalteparin), the second largest selling LMWH product in the United States. Fragmin is currently marketed by Pfizer in the United States and Europe and Kissei Pharmaceutical Co, Ltd. in Japan. The product is indicated for the prevention of DVT following abdominal and hip replacement surgeries and selected indications in ACS. In 2002, Fragmin had worldwide sales of $270 million, representing approximately 11% of the LMWH market. Sales in the United States were approximately $87 million in 2002.

        Similar to Lovenox, Fragmin is currently described by molecular weight distribution, anti-Xa activity and anti-IIa activity. We believe that additional criteria are necessary to fully demonstrate the presence of the same active ingredients to support the filing of a generic application.

        We expect M-Dalteparin will leverage the same technical, regulatory and commercial strategy as M-Enoxaparin. We believe limited technical effort and costs will be required to successfully analyze Fragmin and develop an approvable technology-enabled generic product that could be considered by the FDA to be interchangeable with Fragmin.

        Our plan is to submit a regulatory application for M-Dalteparin in the next 18 to 24 months. Over the next year, we expect to analyze multiple commercial batches of Fragmin and then develop a manufacturing process to produce a therapeutically equivalent product. The Orange Book patent listed for Fragmin will expire in January 2005, prior to our plans for commercialization.

        Over the next few years, many existing therapeutic protein drugs, or biologics, containing sugars which were approved as Biological Licensing Applications, or BLAs, will lose patent and marketing exclusivity protection. Developing generic versions of these drugs will prove challenging because there is significant scientific, regulatory and legal debate about the ability and precedent for developing equivalent versions of these drugs given their inherent complexity. As sugars play a critical role in many of these protein-based products, we may seek to apply our technology to create technology-enabled generic versions of these marketed products, leveraging strategies similar to that of M-Enoxaparin. These product opportunities are longer term because there is uncertainty related to the regulatory approval process for generic biologics.

Improved Development Products

        We are developing proprietary drug candidates based upon our sugar sequencing technology and expertise. We intend to apply our technology to improve existing drugs and develop novel drugs. Our development opportunities include:

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        M118 is a LMWH that we rationally designed to provide improved anti-clotting activity and flexible administration to treat patients with ACS. M118 is a potent inhibitor of multiple factors in the blood that lead to clot formation, whereas currently marketed LMWHs primarily inhibit a single factor contributing to clot formation. This is critical in ACS patients who have an existing clot in a coronary artery because M118 prevents not only the formation of new clots, but also the extension of the existing clot.

        Heparins, including UFH and LMWHs, are used as baseline therapy in ACS, and if required, in subsequent invasive procedures. The selection of a particular heparin is dictated by efficacy, predictability, safety and the ability to monitor the level of and reverse anticoagulation. Due to M118's beneficial biological activities and flexible administration, we believe M118 could be the baseline heparin of choice to treat patients diagnosed with ACS and to treat those patients who subsequently require angioplasty or coronary artery bypass graft surgery, or CABG. Angioplasty is a procedure involving the deployment of a device inside an obstructed artery to restore normal blood flow. CABG is a procedure involving the bypass of a blocked coronary artery with a grafted new artery.

        Market overview.     ACS includes several diseases ranging from unstable angina, which is characterized as chest pain at rest, to acute myocardial infarction, or heart attack, which is caused by a complete blockage of a coronary artery. Approximately 37% of the 1.3 million patients that are diagnosed with ACS in the United States annually respond favorably to initial medical management with anti-clotting agents, such as UFH or LMWH. The remaining patients who do not respond well to this treatment will typically require additional interventional or surgical procedures, such as angioplasty or CABG. Both angioplasty and CABG require anticoagulant therapy to prevent clot formation during the procedure. UFH is currently the foundation anti-clotting agent used in both angioplasty and CABG. There are no LMWHs currently approved for use in either angioplasty or CABG.

        The decision regarding which anti-clotting agent is initially administered depends upon the physician's assessment of the patient's anticipated treatment path. LMWH has demonstrated superior efficacy, or effectiveness, over UFH in the initial clinical setting where patients are managed medically. LMWHs are easier to administer, as they may be injected subcutaneously, as opposed to UFH, which must be administered intravenously. Existing LMWHs, however, have undesirable properties that limit their use in those situations where the patient might require angioplasty or CABG. LMWHs cannot be monitored by standard laboratory clotting tests. If a patient initially receives LMWH in the emergency room and subsequently requires angioplasty, the physician will be unable to quickly determine the degree of anticoagulation previously attained. Consequently, administering too little or too much anticoagulant during the procedure may result in stroke or serious bleeding complications. The ability to monitor UFH thus makes UFH the anti-clotting drug of choice in virtually all patients undergoing angioplasty, even though it has relatively unpredictable biological activities. In addition, LMWHs are not suitable drugs for CABG procedures because their anti-clotting activity cannot be reversed. This is particularly problematic in CABG patients who typically receive protamine sulfate following invasive surgery to reverse the anti-clotting activity of UFH and restore normal clotting mechanisms. Since the physician cannot always determine initially whether a patient will require medical management, angioplasty or CABG, the default anticoagulant chosen for patients entering the emergency room is often UFH.

        M118 development strategy.     To design M118, we utilized our proprietary analytical methods and enzymes, together with our ability to sequence the complex sugar chains within UFH starting material, to identify the sugar sequences responsible for anti-clotting activity. Using our proprietary enzymes to

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precisely cut the longer chains of UFH in specific locations, we developed a drug candidate specifically designed to address the unmet medical needs of anticoagulation therapy in ACS. By choosing M118 as the primary baseline therapy for ACS patients, we believe physicians will be able to deliver safer, more efficacious and consistent therapy, while retaining the flexibility to make the appropriate clinical care treatment decisions for all ACS patients, regardless of the need for medical management, angioplasty or CABG.

        Our preclinical animal studies have demonstrated potential benefits of M118 over UFH and other LMWHs. These potential benefits include:

        M118 is an early preclinical product candidate and, therefore, we have not yet demonstrated statistically significant differences in our animal experiments due to the small number of animals treated.

        Product development status.     M118 is currently in preclinical development. We are working with a third-party manufacturer to produce both our proprietary enzyme and drug substance required in the manufacturing process for M118. The UFH starting material has been obtained from a qualified manufacturer.

        We are currently increasing our manufacturing capabilities to produce sufficient quantities of the drug substance required to develop M118 through the end of Phase I clinical trials. We anticipate that the manufacturing activities will be completed in the first half of 2004.

        We intend to submit an IND to the FDA prior to the end of the first half of 2005 and begin Phase I clinical trials shortly thereafter. We plan to develop M118 through Phase IIa clinical trials and

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then seek a profit-sharing arrangement with a collaborator that includes co-development and co-promotion rights.

        We have identified that sugars facilitate the transport of molecules, including proteins, across mucosal membranes, leading to high levels of bioavailability. Through our sequencing capabilities, we have identified sugars that regulate this transport process. These sugars can be mixed with a variety of protein drugs enabling their delivery across mucosal membranes into the blood stream. We have demonstrated in our animal studies that the sugar transport process is rapid and fully reversible within a matter of minutes, though results from animal tests are not always duplicated when product candidates are tested in humans. In addition, these early preclinical studies did not include adequate numbers of animals to demonstrate statistical significance.

        Our technology targets the many mucosal membranes present in the body, including those membranes in the lungs, nasal passages and gastrointestinal tract. As a result, our technology may enable the pulmonary, nasal or oral delivery of both small and large molecule drugs currently administered by injection. Our current focus is on the pulmonary delivery of therapeutic proteins, where bioavailability has been a challenge. Our initial proof-of-concept, preclinical studies designed to test the delivery of insulin and HGH through the lung, have been completed. In our studies, we have been able to achieve five to ten times greater bioavailability compared with other published advanced technologies in comparable animal studies. In addition, our studies with pulmonary insulin have demonstrated that the insulin remains effective at lowering blood glucose levels.

        Market opportunity.     Based upon industry reports, the estimated market size of the largest therapeutic protein markets, which specifically includes anemia, diabetes, multiple sclerosis, growth hormone deficiency and rheumatoid arthritis, represented a $16.0 billion opportunity in 2001 and is estimated to grow to approximately $30.0 billion in 2010. We believe the largest opportunities for pulmonary formulations of protein drugs are for interferon-beta, also known as Avonex® and Rebif®, which is used to treat multiple sclerosis, and erythropoietin, also known as Epogen® and Procrit®, which is used to treat anemia. We are currently exploring co-development opportunities for our pulmonary insulin and pulmonary HGH programs.

        We are focusing our initial internal development efforts on the following product opportunities:

        Potential benefits of sugar-mediated pulmonary delivery.     We believe our pulmonary delivery of therapeutic proteins has distinct advantages over current technologies. Some of these advantages include:

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        Our analytical and sequencing technologies can also be applied to characterize and re-engineer sugars that exist on the surface of therapeutic proteins. We can engineer new forms of sugars by determining how the manufacturing process changes the distribution of sugars present on the protein, thereby changing biological properties. Altering the complex sugar coat of a protein can potentially improve efficacy and tissue targeting, reduce negative side effects, such as allergic reactions and modify the dosing frequency of the protein drugs. We have also licensed technology that can add or change the sugar units attached to proteins.

        We believe our technology will allow us to efficiently engineer desired modifications to existing proteins, to address significant unmet needs and capitalize on a number of potential product opportunities. For example, unmet needs within chronic diseases such as rheumatoid arthritis, which is treated by anti-TNF agents, include reductions in the dose frequency and increased efficacy among existing therapies. We believe we may be able to affect these multiple properties through the isolation, quantification and systematic modification to the sugar structures on these proteins.

Discovery Product Candidates

        Drug discovery efforts to date have generally ignored the role that complex sugars play in modulating biological systems. Recent research has shown that sugars play a critical role in influencing signaling between proteins in pathways to fundamentally affect basic biology. We believe the role of sugars in disease progression can be exploited to discover novel therapeutics for a range of diseases. We believe a drug discovery program that incorporates both protein and sugar biology will result in the discovery of many new mechanisms that can be targeted with small molecule or antibody drugs. We also believe it will be possible to develop drugs made from sugars to modulate these pathways.

        Our initial area of focus is in oncology. Cancer is a disease characterized by unregulated cell growth. Complex sugars are involved in the conversion of normal cells into cancerous cells, regulating

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tumor growth and playing a role in tumor invasion and metastasis. As normal cells change into cancerous cells, the sugar coats on their cell surfaces also change as part of tumor progression. Detection of these changes potentially provides a new, sensitive means to detect cancer. In addition, since sugars play a role in tumor growth and metastasis, the introduction of sugar structures that can prevent these processes provides a potential avenue for development of new therapeutics. We have shown through studies that these sugars selectively inhibit proliferation of cancer cells and increase apoptosis, or cell death. Finally, a better understanding of the role that sugars play in modulating protein pathways can aid in the understanding of cancer mechanisms and the discovery of new small molecule and antibody drugs.

        Sugar-based drugs.     We have identified sugar sequences that have demonstrated potent anti-tumor effects in animals, as compared with control groups. Results from early testing in animals, however, are not always duplicated when product candidates are tested in humans. These sugar sequences were capable of both inhibiting tumor growth and preventing metastasis. These anti-cancer activities were obtained at microgram per kilogram doses, one thousand fold below the projected clinical dose, demonstrating the high potency of these compounds, though these early preclinical studies did not include adequate numbers of animals to demonstrate statistical significance.

        Sugar-based diagnostics.     Prostate specific antigen, or PSA, is a protein expressed by the prostate in human males. When males develop cancer of the prostate, the level of PSA expressed in the blood increases. We have determined that there are distinctive changes that occur in the sugars that are bound to the PSA protein that can better discriminate between cancerous and non-cancerous states. We believe our technology could be used to develop an improved diagnostic of prostate cancer. We are evaluating whether to devote resources to further pursue development of sugar-based diagnostics.

Collaboration and Licenses

Sandoz

        In November 2003, we entered into a collaboration and license agreement with Sandoz to jointly develop and commercialize injectable enoxaparin and any improved injectable form of enoxaparin for which Lovenox is the reference listed drug and for which an ANDA could be approved by the FDA. Under the terms of this agreement, we and Sandoz agree to exclusively work with each other to develop and commercialize injectable enoxaparin for any and all medical indications within the United States. In addition, we granted Sandoz an exclusive license, under our intellectual property rights, to develop and commercialize injectable enoxaparin for all medical indications within the United States.

        We have granted to Sandoz the right to negotiate additional rights under certain circumstances. Sandoz has exercised an exclusive right to negotiate an exclusive license to develop and commercialize injectable enoxaparin outside of the United States. We will negotiate in good faith a definitive agreement on terms generally consistent with the agreement, but with certain specified variations. If we and Sandoz have not entered into a license agreement by November 1, 2004, then we may arrange to work with third parties to develop or commercialize injectable enoxaparin, provided that we give Sandoz a right of first refusal with respect to such activities. Further, Sandoz may exercise a right of first negotiation to work with us on the research, development, manufacturing or commercialization, inside and/or outside the United States, of a generic version of Fragmin, M118, and/or enoxaparin administered by any route of delivery other than injection or certain improved forms of enoxaparin for which approval by the FDA would require the filing of a NDA. If Sandoz does not exercise its negotiation right, or if it does exercise its negotiation right for any of these opportunities, but we and Sandoz do not execute a definitive agreement within a specified time frame, then, for a specified time, we are permitted to enter into a transaction for such opportunity with a third party, provided that, under certain circumstances, the terms which we give to that third party can be no less favorable, taken as a whole, to us than the terms last offered to Sandoz. If we do not enter into a transaction with a

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third party in the specified time frame, then Sandoz may again exercise the right of first negotiation with respect to these opportunities.

        Under this collaboration, Sandoz will make certain payments to us. We will provide, and Sandoz will pay us for, a minimum amount of full-time equivalent scientific, technical and/or management work over the course of the 24-month period that commenced on October 1, 2003. Sandoz is also responsible for funding substantially all of the other ongoing development and commercialization costs and legal expenses incurred with respect to injectable enoxaparin, subject to an agreed-upon limit. To date, Sandoz has paid us approximately $2.0 million for our work and the reimbursement of development costs. In addition, Sandoz will share profits with us or pay royalties to us on net sales of injectable enoxaparin by Sandoz, its affiliates or distributors in the United States. If certain regulatory or commercial milestones are achieved with respect to injectable enoxaparin under certain circumstances, Sandoz may also make certain milestone payments to us, which would reach $55.0 million if all such milestones are achieved. If the development expenses and certain legal expenses, in the aggregate, exceed a specified amount, Sandoz is permitted to offset a portion of the excess against the profit-sharing amounts, the royalties and the commercial milestone payments. Sandoz may also offset a portion of any product liability costs and certain other expenses arising from patent litigation against the profit-sharing amounts, the royalties and the commercial milestone payments.

        The collaboration is governed by a joint steering committee and a joint project team, each consisting of an equal number of Sandoz and Momenta representatives. Most decisions must be made unanimously, with Sandoz collectively having one vote and us having one vote. Sandoz has sole authority to make decisions with respect to any litigation claiming that the manufacture, use or sale of the injectable enoxaparin product infringes any patents listed in the Orange Book for Lovenox. In addition, Sandoz has the sole authority to determine whether or not to launch the injectable enoxaparin product prior to receipt of final legal clearance from any such infringement claims, as well as the price at which it will sell the injectable enoxaparin product. Sandoz is also responsible for the filing of the ANDA.

        We and Sandoz will indemnify each other for losses resulting from the indemnifying party's misrepresentation or breach of its obligations under the agreement. We will indemnify Sandoz if we actually misappropriate the know-how or trade secrets of a third party. Sandoz will indemnify us and our collaborators involved in the enoxaparin program for any losses resulting from any litigation by third parties, including Aventis, claiming that the manufacture, use or sale of injectable enoxaparin infringes any patents listed in the Orange Book for Lovenox, any product liability claims with respect to injectable enoxaparin and any other claims relating to the development and commercialization of injectable enoxaparin. To the extent that any losses result from a third party claim for which we are obligated to indemnify Sandoz, Sandoz will have no obligation to indemnify us. After the expiration or termination of the agreement, these indemnification obligations will continue with respect to claims that arise before or after the termination of the agreement due to activities that occurred before or during the term of the agreement.

        Unless terminated earlier, the agreement will expire upon the last sale of injectable enoxaparin by or on behalf of Sandoz in the United States. Either party may terminate the collaboration relationship for material uncured breaches or certain events of bankruptcy or insolvency by the other. Sandoz may also terminate the agreement if the product or the market lacks commercial viability, if we fail to meet certain development milestones, if new laws or regulations are passed or court decisions rendered that substantially diminish our legal avenues for redress, or, in multiple cases, if certain costs exceed mutually agreed upon limits. If Sandoz terminates the agreement (except due to our uncured breach) or if we terminate the agreement due to an uncured breach by Sandoz, we will be granted an exclusive license under certain intellectual property of Sandoz to develop and commercialize injectable enoxaparin in the United States and our obligation to indemnify Sandoz will survive with respect to claims that arise due to our exclusive development or commercialization of injectable enoxaparin after

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the term of the agreement. In the event of a termination by Sandoz due to the incurrence of costs beyond the agreed upon limits, we must pay certain royalties to Sandoz on our net sales of injectable enoxaparin. If Sandoz terminates the agreement due to our uncured breach, Sandoz retains the exclusive right to develop and commercialize injectable enoxaparin in the United States, and, if the negotiation period with respect to a license outside of the United States is not yet complete, Sandoz shall continue to have the right to negotiate an exclusive license. In addition, Sandoz' profit sharing, royalty and milestone payment obligations survive and Sandoz' obligation to indemnify us will survive with respect to claims that arise due to Sandoz' exclusive development or commercialization of injectable enoxaparin after the term of the agreement. In addition, if Sandoz terminates the agreement due to our uncured breach, Sandoz would retain its rights of first negotiation with respect to certain of our other products.

Massachusetts Institute of Technology

        In December 2001, we entered into a patent license agreement with the Massachusetts Institute of Technology, or M.I.T., pertaining to the characterization and synthesis of sugars for the purpose of researching, developing and commercializing products (other than sequencing machines) and processes under the licensed patents. This agreement was subsequently amended and restated in early November 2002 and further amended in 2003 and 2004. We entered into an additional patent license agreement with M.I.T. in late October 2002 which gave us the right to develop and commercialize sequencing machines. These two agreements grant us various exclusive and nonexclusive worldwide licenses, with the right to grant sublicenses, under certain patents and patent applications relating to (i) methods and technologies for characterizing sugars, (ii) certain heparins, heparinases and other enzymes, and (iii) synthesis methods.

        Subject to typical retained rights of M.I.T. and the United States government, we are granted: various exclusive and nonexclusive rights to certain methods and technologies, heparinases and other enzymes for the purpose of characterizing sugars, manufacturing products, and selling or leasing sequencing machines; exclusive rights to certain novel heparins and heparinases, including M118, for use as therapeutics; and nonexclusive rights to certain methods and technologies for the synthesis of sugars for use as therapeutics.

        We have a first option to expand our exclusive licenses by adding rights to those patentable inventions which are made by certain M.I.T investigators by December 31, 2004 and which are dominated by claims of certain of the patents or applications under which we are exclusively licensed, provided that we pay a fee to M.I.T.

        We must meet certain diligence requirements in order to maintain our licenses under the two agreements. Under the agreements, we must expend at least $0.25 million during 2004 and at least $1.0 to $1.2 million per year commencing with 2005 towards the research, development and commercialization of products and processes covered by the agreements. In addition, we are obligated to make first commercial sales and meet certain minimum sales thresholds of products or processes including, under the amended and restated agreement, a first commercial sale of a product or process no later than June 2013 and minimal sales of products thereafter, ranging from $0.5 million to $5.0 million annually. M.I.T. may convert the exclusive licenses granted to us under the amended and restated license agreement to non-exclusive licenses, as its sole remedy, if we fail to meet our diligence obligations. Under the license agreement covering sequencing machines, M.I.T. has the right to treat our failure to fulfill our diligence obligations as a material breach of the license agreement.

        In exchange for the licenses granted in the two agreements, we paid M.I.T. license issue fees and we pay annual license maintenance fees. To date, we have paid M.I.T. approximately $0.3 million in license issue fees and annual license maintenance fees pursuant to these agreements. Starting in 2005, we are required to pay annual license maintenance fees pursuant to these agreements ranging, in the aggregate, from $82,500 to $157,500. In addition, in exchange for the licenses granted under the

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amended and restated license agreement, M.I.T. was issued 293,136 shares of our common stock valued at $0.3 million and certain employees of M.I.T. who are inventors of the licensed patents and patent applications were issued an aggregate of 81,852 shares of our common stock valued at $0.1 million. We are also required to pay M.I.T. royalties on products and services covered by the licenses and sold by us or our affiliates or sublicensees, a percentage of certain other income received by us from corporate partners and sublicensees, and certain patent prosecution and maintenance costs.

        We are obligated to indemnify M.I.T. and related parties from losses arising from claims relating to the products, processes or services made, used, sold or performed pursuant to the agreements, unless the losses result from the indemnified parties' gross negligence or willful misconduct.

        Each agreement expires upon the expiration or abandonment of all issued patents and filed patent applications licensed to us by M.I.T. under such agreement. The issued patents include 10 United States patents that expire between 2012 and 2020, and a number of foreign patents that expire between 2012 and 2013. We expect that additional patents will issue from filed patent applications. Any such patent will have a term of 20 years from the filing date of the underlying application. M.I.T. may terminate either or both agreements immediately if we cease to carry on our business, if any nonpayment by us is not cured within 60 days of written notice or if we commit a material breach that is not cured within 90 days of written notice. We may terminate either or both agreements for any reason upon six months notice to M.I.T., and, under one agreement, we can separately terminate the license under a certain subset of patent rights upon three months notice.

        We have granted Sandoz a sublicense under the amended and restated license agreement to certain of the patents and patent applications licensed to us. If M.I.T. converts our exclusive licenses under this agreement to non-exclusive due to our failure to meet diligence obligations, or if M.I.T. terminates this agreement, M.I.T. will honor the exclusive nature of the sublicense we granted to Sandoz so long as Sandoz continues to fulfill its obligations to us under the collaboration and license agreement we entered into with Sandoz and, if our agreement with M.I.T. is terminated, Sandoz agrees to assume our rights and obligations to M.I.T.

The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory

        In November 2002, we entered into an agreement with The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory, or Lawrence Berkeley National Lab, under which we exclusively licensed certain patents and patent applications covering the metabolic synthesis of sugars and glycoconjugates. Subject to typical retained rights of Lawrence Berkeley National Lab and the United States government, we were initially granted an exclusive license, with the right to grant sublicenses, for the synthesis, production or modification of sugars and glycoconjugates in or on biological molecules for purposes of researching, developing and commercializing products, services and processes for all human therapeutic applications, excluding the sale of research reagents. After November 20, 2004, we may retain the license under this broad field if we pay a fee and have met certain diligence obligations. These obligations include hiring a vice president of research and development and having established an internal or collaborative program (in which we are expected to earn at least $0.5 million) for the clinical development of a product candidate. If we do not pay the fee and fulfill the diligence obligations, the field narrows to three therapeutic applications that we select from an agreed upon list, each to be more thoroughly defined through negotiation with Lawrence Berkeley National Lab. Upon our request, but subject to statutory restrictions or obligations to research sponsors, Lawrence Berkeley National Lab must disclose certain information that is necessary or useful for our use of the licensed patent rights and we have a non-exclusive, royalty-free right to use such information.

        Lawrence Berkeley National Lab has an obligation to notify us of certain future inventions that are available for licensing by Lawrence Berkeley National Lab prior to entering into negotiations with

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others. However, Lawrence Berkeley National Lab is not required to license those inventions to us, or even to negotiate with us.

        In return for these license rights, we paid Lawrence Berkeley National Lab a license issue fee of $40,000. We are also required to pay Lawrence Berkeley National Lab earned royalties on products, services and processes covered by the license and sold by us or our affiliates or sublicensees, a percentage of certain other income received by us from our sublicensees, and patent prosecution and maintenance costs. To the extent that earned royalties in any given year do not meet certain threshold amounts, we are required to make annual minimum royalty payments to Lawrence Berkeley National Lab, ranging from $10,000 to $60,000, in order to maintain the license.

        In order to maintain our license, we must expend at least $0.5 million during 2004 and at least $1.0 million per year commencing with 2005 towards the research, development and commercialization of products covered by the agreement. If we fail to do so, Lawrence Berkeley National Lab may renegotiate the milestones, terminate the agreement or convert the exclusive license to a non-exclusive license.

        We are obligated to indemnify Lawrence Berkeley National Lab, the United States government and related parties from claims arising from our or our sublicensees' exercise of rights under the agreement, unless the claims result from the indemnified parties' gross negligence or willful misconduct.

        The agreement expires upon the later of the expiration, abandonment or final adjudication of invalidity of the licensed patents. The licensed patents consist of two United States patents that expire in 2017 and one United States patent application. Any patent issuing from such application will have a term of 20 years from the date such application was filed. Our license to use the know-how acquired from Lawrence Berkeley National Lab is paid-up and perpetual following the expiration, but not an earlier termination, of the agreement. Either party may terminate the agreement for the other's material breach with a 90 day cure period, although Lawrence Berkeley National Lab may terminate if we do not cure payment breaches within 30 days. We may terminate the agreement for any reason upon 180 days notice. Upon termination of the agreement, we are required to assign each sublicense to Lawrence Berkeley National Lab and Lawrence Berkeley National Lab is required to assume it unless the sublicensee is then in breach or the sublicense conflicts with Lawrence Berkeley National Lab's obligations to state or federal governments.

Manufacturing

        We do not own facilities for manufacturing any products. Although we intend to rely on contract manufacturers, we have personnel with manufacturing experience to oversee the production of M-Enoxaparin, M-Dalteparin, M118 and future products that we may develop.

        In each of our agreements with contract manufacturers, we retain ownership of our intellectual property and generally own and/or are assigned ownership of processes, developments, data, results and other intellectual property generated during the course of the performance of each agreement that primarily relate to our products. Where applicable, we are granted non-exclusive licenses to certain contract manufacturer intellectual property for purposes of exploiting the products that are the subject of the agreement and in a few instances we grant non-exclusive licenses to the contract manufacturers for use outside of our product area. In each contract, we have the right to terminate for convenience. The agreements also contain typical provisions for both parties to terminate for material breach and bankruptcy and insolvency.

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M-Enoxaparin

        In October 2003, we entered into a process development and production agreement with Siegfried (USA), Inc. and Siegfried Ltd. that was subsequently amended in May 2004, under which we provide to Siegfried our existing laboratory-scale processes and analytical methods for the production of M-Enoxaparin. Siegfried's responsibility is to further develop the processes and once we approve of such processes, manufacture the active pharmaceutical ingredient, enoxaparin sodium, for use in stability, preclinical and clinical studies and for other development purposes. During the term of the agreement and for a period of time thereafter, Siegfried commits to work with us on the development and production of M-Enoxaparin on an exclusive basis. To date, we have paid Siegfried $0.2 million for development work under the agreement. We have committed to pay Siegfried up to an additional $2.0 million for development and production work which is expected to be paid through 2005.

        Under the agreement, we retain ownership of our intellectual property we provide to Siegfried and we exclusively own all intellectual property that is developed or made and/or reduced to practice by Siegfried pursuant to the agreement and that pertains to M-Enoxaparin. Further, Siegfried granted us, in order to develop, make, use, sell and import M-Enoxaparin, a non-exclusive, worldwide, irrevocable, sublicensable, royalty-free license to Siegfried's previously existing intellectual property and to intellectual property acquired by Siegfried apart from the agreement. To the extent that any of the intellectual property developed under the agreement has application to products other than heparins, we granted Siegfried, in order to develop, make, use, sell and import products that are not heparins, a non-exclusive, worldwide, irrevocable, non-sublicensable, royalty-free license to such intellectual property.

        Siegfried is obligated to indemnify us for third-party product liability claims which result from the failure of the product to meet certain requirements and/or the negligence or misconduct of Siegfried. We are obligated to indemnify Siegfried for all other third-party product liability claims which result from the production, use or consumption of the product. In connection with the development and production of the product, Siegfried is obligated to indemnify us for any alleged infringement of any patent or other intellectual property right by a third party which results from a breach of certain intellectual property representations and warranties made by Siegfried. In connection with the development and production of the product, we are obligated to indemnify Siegfried for all other alleged infringements of any patent or other intellectual property right by a third party.

        The agreement expires upon the completion of the development and production of the product. Either party may terminate the agreement: for the other's material breach which is not cured within 15 days; if such party reasonably determines that, for valid scientific or technical reasons, the goals of the agreement cannot be achieved within the agreed upon parameters or timelines and a modification is not agreed upon within 30 days; and, to the extent permitted by law, if the other party opens bankruptcy proceedings, goes into receivership, or allows its creditors to place the company in receivership. In addition, if unforeseen circumstances render the development and production materially more costly and we do not agree to an increase in the amount payable to Siegfried, Siegfried has the right to treat such decision as a valid scientific or technical obstacle and terminate the agreement. We may also terminate the agreement for any reason upon 30 days notice.

        We are working with a provider for analytical testing, method transfer, validation and preparation work and for comparability studies for M-Enoxaparin and are negotiating with a contract manufacturer to produce M-Enoxaparin in finished dose form for development and clinical use.

M-Dalteparin

        Should we require process development of M-Dalteparin, we expect the manufacture of M-Dalteparin would require similar process development as M-Enoxaparin; however, we may or may not use the same contract manufacturers selected for M-Enoxaparin.

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M118

        We are working with a provider to perform process development and enzyme production work for a specific heparinase enzyme which is used to produce M118. In addition, we are working with a contract manufacturer with regard to our existing laboratory-scale processes and analytical methods for the production of M118, including the heparinase enzyme used to produce M118.

Sales and Marketing

        We do not currently have any sales and marketing capabilities. In order to commercialize any products that are approved for commercial sale, we must either develop a sales and marketing infrastructure or collaborate with third parties that have sales and marketing experience. We plan to build a small, highly-focused, specialty sales and marketing infrastructure. Given that most of our products address patients who are either hospitalized or recently discharged from the hospital, we intend to focus our sales and marketing capabilities in these areas. In addition, we plan to enter into collaborations with established industry participants in key markets outside North America, including the European Union.

Competition

        The development and commercialization of pharmaceutical products is highly competitive. In the event that we were to market and sell M-Enoxaparin, we would face competition from Aventis which is currently marketing Lovenox, and potentially from other firms marketing generic versions of Lovenox. Aventis may also choose to market a generic version of Lovenox itself or through an authorized third-party distributor. While there are no generic versions of Lovenox approved by the FDA to date, ANDAs have been submitted to the FDA by Amphastar and Teva, and other ANDAs or other regulatory applications may be submitted in the future. Any generic enoxaparin application must demonstrate that its product has the same active ingredients as Lovenox, in accordance with the FDA's requirement for therapeutic equivalence and to be considered interchangeable with Lovenox. We believe that other firms submitting ANDAs will face difficulty in demonstrating that they have the same active ingredients as Lovenox, given the difficulties associated with the detailed analysis of Lovenox. M-Dalteparin will face similar competition from Pfizer, which is currently marketing Fragmin, and other manufacturers seeking to commercialize generic versions of Fragmin in the United States.

        In addition, other anticoagulants used in the treatment of DVT and ACS will compete with our products. These competitors include:

    Sanofi-Synthelabo's factor Xa inhibitor, Arixtra®, which has multiple indications in DVT;

    The Medicines Company's direct thrombin inhibitor, Angiomax®, which is approved for use in angioplasty; and

    various UFH products.

        We are aware of other anticoagulant drugs in development, including AstraZeneca's Exanta®, which is currently in Phase III clinical trials, as well as multiple factor Xa inhibitors in clinical trials.

        M118 faces competition from similar compounds, including other LMWHs, UFH, as well as anti-platelet and direct thrombin inhibitors which may be used in the treatment of ACS. As the treatment for ACS evolves, other classes of products may become increasingly more important in the treatment of ACS; however, we believe that LMWH therapy will remain a critical element of ACS treatment. AstraZeneca and Sanofi-Synthelabo have publicly disclosed they will seek approval for selected ACS indications for Exanta and Arixtra, respectively.

        In the areas of non-invasive drug delivery, there are many companies seeking to advance pulmonary delivery for therapeutic proteins. Current companies active in the drug delivery field include

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Alkermes Inc., Aradigm Corporation, Aventis, Eli Lilly and Co., Nektar Therapeutics, Novo Nordisk A/S and Pfizer. In addition, there are many major pharmaceutical firms who may pursue non-invasive delivery as line extension strategies for existing products. These companies could become competitors or collaborators for our inhaled product portfolio.

        Similarly, our discovery work in oncology faces substantial competition from major pharmaceutical and other biotechnology companies that are actively working on improved and novel therapeutics. Companies competing most directly with our approach of developing sugar-based therapeutics for oncology include GlycoGenesys Inc. and Progene.

        The key competitive factors affecting the overall success of our prospective drug products include: product effectiveness, safety, timing and scope of regulatory approval, price, availability of supply/manufacturing efficiency, and patent protection.

        Companies may also emerge as competitors over time, as their technology and products may reduce market demand for our technology and/or products. Examples of potential future competitors include companies working on:

    Novel drug products in our target therapeutic areas, such as new cardiovascular therapies that significantly alter the market potential for existing drug products to which we may apply our technology;

    Novel drug products possessing superior clinical attributes to our development candidates;

    Alternative delivery mechanisms for drug products in our target therapeutic areas which may decrease the attractiveness of our molecules, such as oral heparin products which may reduce the demand for subcutaneous drug products, even those with improved product profiles; and

    Second-generation versions of drugs which are subject to research and development efforts within pharmaceutical companies that may alter the demand for selected products.

        The field of glycobiology is a growing field with increased competition. While we are not aware of others that are taking a similar approach to detailed chemical characterization of complex sugars, there are companies that could be viewed as competitors in the broader context of glycobiology. In addition to major pharmaceutical and biotechnology companies which have successfully improved products through sugar modification, such as Amgen and Biogen Idec Inc., there are many companies with glycobiology capabilities, including BioTie Therapies Oyj, GLYCO Design Inc., GlycoFi, Inc., Neose Technologies, Inc., Procognia Limited and Pro-Pharmaceuticals Inc. Competitive factors distinguishing companies include the breadth and comprehensiveness of their analytic capabilities, the strength of their patent estates, as well as their relative emphasis on analysis, synthesis, or engineering of complex sugars. Many of these companies are focused on providing services to pharmaceutical companies rather than focused on drug discovery and product development.

Patents and Proprietary Rights

        Our success depends in part on our ability to obtain and maintain proprietary protection for our technology and product candidates, to operate without infringing on the proprietary rights of others and to prevent others from infringing our proprietary rights. Our policy is to seek to protect our proprietary position by, among other methods, filing United States and foreign patent applications related to our proprietary technology and product candidates that are important to the development of our business. We also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop and maintain our proprietary position.

        We license or own a total of 12 United States patents and 24 United States patent applications as well as 17 foreign patents and 48 foreign patent applications which are counterparts to certain of the United States patents and patent applications. Our patent portfolio includes claims covering: methods

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and technologies for characterizing sugars; the use of certain naturally occurring heparinases, heparinase variants and other enzymes which specifically recognize polysaccharides in the characterization of sugars; methods and technologies for chemical and metabolic synthesis of sugars; the composition of matter of certain novel LMWHs, including M118, and heparinase variants; methods to produce and identify sugars associated with glycoproteins; methods to analyze and monitor glycoprotein profiles for purposes associated with the diagnosis, staging, prognosis and monitoring of cancer; and methods for the in vivo non-invasive delivery of sugars.

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        The following is a table that sets forth the 12 United States patents we license:

U.S. Number

  Filing Date/
Issue Date

  Expiration
Date

  Licensor
  Title

5,714,376

 

10/23/91
02/03/98

 

02/03/2015

 

M.I.T.

 

Heparinase Gene From Flavobacterium Heparinum

5,830,726

 

05/19/95
11/03/98

 

11/03/2015

 

M.I.T.

 

Method for Obtaining A Modified Heparinase Gene

5,389,539

 

11/30/92
02/14/95

 

11/30/2012

 

M.I.T. – University of Iowa Research Foundation

 

Purification Of Heparinase I, II, and III From Flavobacterium Heparinum

5,569,600

 

01/26/95
10/29/96

 

10/29/2013

 

M.I.T. – University of Iowa Research Foundation

 

Purification, Composition, and Specificity Of Heparinase I, II, And III From Flavobacterium Heparinum

5,607,859

 

03/28/94
03/04/97

 

03/28/2014

 

M.I.T.

 

Methods And Products For Mass Spectrometric Molecular Weight Determination Of Polyionic Analytes Employing Polyionic Reagents

6,597,996

 

04/24/00
07/22/03

 

04/24/2020

 

M.I.T.

 

Method For Identifying Or Characterizing Properties of Polymetric Units

6,323,339

 

10/06/99
11/27/01

 

10/06/2019

 

M.I.T.

 

Synthesis of Oligosaccharides, Reagents And Methods Related Thereto

6,579,725

 

03/03/00
06/17/03

 

03/03/2020

 

M.I.T.

 

Linkers for Synthesis of Oligosaccharides On Solid Supports

6,426,421

 

11/21/00
07/30/02

 

11/21/2020

 

M.I.T.

 

Protecting Groups Useful in the Synthesis Of Polysaccharides, Natural Products, And Combinatorial Libraries

6,693,178

 

05/15/02
02/17/04

 

11/21/2020

 

M.I.T.

 

Protecting Groups Useful In The Synthesis Of Polysaccharides, Natural Products, And Combinatorial Libraries

6,075,134

 

05/15/97
06/13/00

 

05/15/2017

 

The Regents of the University of California

 

Glycoconjugates and Methods

6,458,937

 

05/16/00
10/01/02

 

05/15/2017

 

The Regents of the University of California

 

Glycoconjugates and Methods

        A significant portion of our patent portfolio covering methods and technologies for characterizing sugars consists of patents and patent applications owned and licensed to us by M.I.T. In addition, a

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significant portion of the claims in our patent portfolio covering the composition of matter of naturally occurring heparinases, heparinase variants and other enzymes, the use of these heparinases and enzymes in the characterization of sugars, the methods and technologies for chemical synthesis of sugars, and the composition of matter of novel low molecular weight heparins consist of patents and patent applications that are owned and licensed to us by M.I.T. The claims in our patent portfolio covering the methods and technologies for metabolic synthesis of sugars consist of patents and patent applications that are owned and licensed to us by Ernest Orlando Lawrence Berkeley National Laboratory.

        The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. Our ability to maintain and solidify our proprietary position for our technology will depend on our success in obtaining effective claims and enforcing those claims once granted. We do not know whether any of our patent applications will result in the issuance of any patents. Moreover, any issued patent does not guarantee us the right to practice the patented technology or commercialize the patented product. Third parties may have blocking patents that could be used to prevent us from commercializing our patented products and practicing our patented technology. Our issued patents and those that may be issued in the future may be challenged, invalidated or circumvented, which could limit our ability to stop competitors from marketing related products or the length of the term of patent protection that we may have for our products. In addition, the rights granted under any issued patents may not provide us with proprietary protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies. For these reasons, we may have competition for both our generic and novel products. Moreover, because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that, before any of our novel heparin or other products can be commercialized, any related patent may expire or remain in force for only a short period following commercialization, thereby reducing any advantage of the patent.

        We may rely, in some circumstances, on trade secrets to protect our technology. However, trade secrets are difficult to protect. We seek to protect our technology and product candidates, in part, by confidentiality agreements with our employees, consultants, advisors, contractors and collaborators. These agreements may be breached and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our employees, consultants, advisors, contractors and collaborators use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting know-how and inventions.

Regulatory and Legal Matters

        Government authorities in the United States, at the federal, state and local level, and other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, promotion, advertising, distribution, marketing and export and import of products such as those we are developing.

United States Government Regulation

        In the United States, the information that must be submitted to the FDA in order to obtain approval to market a new drug varies depending on whether the drug is a new product whose safety and effectiveness has not previously been demonstrated in humans or a drug whose active ingredient(s) and certain other properties are the same as those of a previously approved drug. A new drug will follow the NDA route, a new biologic will follow the BLA route, and a drug that claims to be the same as an already approved drug may be able to follow the ANDA route. Medical devices are approved or cleared for marketing through either the premarket approval application process, or PMA process, or

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the 510(k) clearance process. Drugs or biologics that are combined with medical devices may be regulated as combination products through one or more of the FDA's regulatory pathways.

        In the United States, the FDA regulates drugs and biologics under the Federal Food, Drug, and Cosmetic Act, and, in the case of biologics, also under the Public Health Service Act, and implementing regulations. Failures to comply with the applicable United States requirements at any time during the product development process, approval process or after approval, may subject an applicant to administrative or judicial sanctions. These sanctions could include the FDA's refusal to approve pending applications, license suspension or revocation, withdrawal of an approval, a clinical hold, warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties or criminal prosecution. Any agency or judicial enforcement action could have a material adverse effect on us.

        The steps required before a drug or biologic may be marketed in the United States include:

        Preclinical tests include laboratory evaluations of product chemistry, toxicity, and formulation, as well as animal studies. An IND sponsor must submit the results of the preclinical tests, together with manufacturing information and analytical data, to the FDA as part of the IND. An IND will automatically become effective 30 days after receipt by the FDA, unless before that time, the FDA raises concerns or questions about issues such as the conduct of the trials as outlined in the IND. In that case, the IND sponsor and the FDA must resolve any outstanding FDA concerns or questions before clinical trials can proceed. Submission of an IND may not result in the FDA allowing clinical trials to commence.

        Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators. Clinical trials are conducted under protocols detailing, among other things, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each clinical protocol must be submitted to the FDA as part of the IND, and an IRB at each site where the study is conducted must also approve the study.

        Clinical trials typically are conducted in three sequential phases, but the phases may overlap or be combined. Phase I trials usually involve the initial introduction of the investigational drug into humans to evaluate the product's safety, dosage tolerance and pharmacodynamics and, if possible, to gain an early indication of its effectiveness.

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        Phase II trials usually involve controlled trials in a limited patient population to:

        Phase III trials usually further evaluate clinical efficacy and test further for safety in an expanded patient population. Phase I, Phase II and Phase III testing may not be completed successfully within any specified period, if at all. Furthermore, the FDA or we may suspend or terminate clinical trials at any time on various grounds, including a finding that the subjects or patients are being exposed to an unacceptable health risk.

        Assuming successful completion of the required clinical testing, the results of the preclinical studies and of the clinical studies, together with other detailed information, including information on the chemistry, manufacture and control criteria of the product, are submitted to the FDA in the form of an NDA or BLA requesting approval to market the product for one or more indications. The FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing is cGMP-compliant to assure and preserve the product's identity, strength, quality and purity. The FDA reviews a BLA to determine, among other things, whether the product is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product's continued safety, purity and potency.

        Before approving an NDA or BLA, the FDA will inspect the facility or the facilities at which the product is manufactured. The FDA will not approve the product unless cGMP compliance is satisfactory. If the FDA determines the application, manufacturing process or manufacturing facilities are not acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

        The testing and approval process requires substantial time, effort and financial resources, and each may take several years to complete. The FDA may not grant approval on a timely basis, or at all. We may encounter difficulties or unanticipated costs in our efforts to secure necessary governmental approvals, which could delay or preclude us from marketing our products. The FDA may limit the indications for use or place other conditions on any approvals that could restrict the commercial application of the products. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further FDA review and approval.

        FDA approval is required before a generic equivalent of an existing brand name drug can be marketed. Such approval for products is typically obtained by submitting an ANDA to the FDA and demonstrating therapeutic equivalence. However, it is within the FDA's regulatory discretion to determine the kind and amount of evidence required to approve a product for marketing. Although the FDA has accepted ANDAs for generic versions of Lovenox for review, the FDA could determine that therapeutic equivalence cannot be shown for M-Enoxaparin and require an NDA for approval. An ANDA may be submitted for a drug on the basis that it is the same as a previously approved branded drug, also known as a listed drug. Specifically, the generic drug that is the subject of the ANDA must have the same active ingredient(s), route of administration, dosage form, and strength, as well as the same labeling, with certain exceptions, and the labeling must prescribe the same conditions of use as the listed drug. If the generic drug product has a different route of administration, dosage form, or strength, the FDA must grant a suitability petition approving the differences(s) from the listed drug before the ANDA may be filed. The ANDA must also contain data and information demonstrating that

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the generic drug is bioequivalent to the listed drug, or if the application is submitted pursuant to an approved suitability petition, information to show that the active ingredients in the generic drug are the same pharmacological or therapeutic class as those of the listed drug and that the generic drug can be expected to have the same therapeutic effect as the listed drug when administered to patients for a proposed condition of use.

        Generic drug applications are termed "abbreviated" because they are not required to duplicate the clinical (human) testing or, generally, preclinical testing necessary to establish the underlying safety and effectiveness of the branded product. However, the FDA may refuse to approve an ANDA if there is insufficient information to show that the active ingredients are the same and to demonstrate that any impurities or differences in active ingredients do not affect the safety or efficacy of the generic product. In addition, like NDAs, an ANDA will not be approved unless the product is manufactured in cGMP-compliant facilities to assure and preserve the drug's identity, strength, quality and purity. Moreover, submission of an ANDA does not guarantee it will be deemed acceptable for filing and review; the FDA may refuse to accept for filing applications it finds insufficiently complete.

        Determination of the "sameness" of the active ingredients to that in the listed drug is based on the demonstration of the chemical equivalence of the components of the generic version to those of the branded product. The FDA defines active ingredients as "any component that is intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body of man or other animals. The term includes those components that may undergo chemical change in the manufacture of the drug product and be present in the drug product in a modified form intended to furnish the specified activity or effect." While the standard of demonstrating chemical equivalence is relatively straightforward for small molecule drugs, it is inherently more difficult to define active ingredients for complex drugs, including those made from naturally occurring biological substances. These include heparins, therapeutic proteins, vaccines and antibiotics. The FDA has not reached a final position or provided specific guidance for demonstrating chemical equivalence for many of these products as criteria are in many cases, still evolving.

        To demonstrate bioequivalence, ANDAs generally must also contain in vivo bioavailability data for the generic and branded drugs. "Bioavailability" indicates the rate and extent of absorption and levels of concentration of a drug product in the blood stream needed to produce a therapeutic effect. "Bioequivalence" compares the bioavailability of one drug product with another, and when established, indicates that the rate of absorption and levels of concentration of a generic drug in the body are the same as the previously approved branded drug. If the rate of absorption is different but the extent of absorption is the same, and the difference in rate is intentional and reflected in the proposed labeling, two drugs may be considered bioequivalent if the difference is not essential to the effective attainment of body drug concentrations on chronic use, and is considered medically insignificant for the drug. The studies required to demonstrate in vivo bioequivalence are generally very small, quick to complete, and involve few patients. Under current regulations, for certain drug products where bioequivalence is self-evident such as injectable solutions which have been shown to contain the same active and inactive ingredients as the listed drug, the FDA may waive the requirement for in vivo bioequivalence data. Thus, most generic injectable products approved to date have been able to successfully obtain waivers to bioequivalence testing in humans.

        Generic drug products that are found to be therapeutically equivalent by the FDA receive an "A" rating in FDA's Orange Book, which lists all approved drug products and therapeutic equivalence evaluations. Products that are therapeutically equivalent can be expected in FDA's judgment to have equivalent clinical effect and no difference in their potential for adverse effects when used under the conditions of their labeling. Products with "A" ratings are generally substitutable for the innovator drug by both in-hospital and retail pharmacies. Many health insurance plans require automatic substitution

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for "A" rated generic versions of products when they are available, although physicians may still prescribe the branded drug for individual patients.

        The timing of final FDA approval of a generic drug for commercial distribution depends on a variety of factors, including whether the applicant challenges any listed patents for the drug and/or its use and whether the manufacturer of the branded product is entitled to one or more statutory exclusivity periods, during which the FDA is prohibited from approving generic products. In addition, submission of an ANDA for a drug that was a new molecular entity when approved will be blocked for five years after the pioneer's approval, or for four years after approval if the application includes a paragraph IV certification of non-infringement or invalidity against a patent applicable to the branded drug. This does not apply to M-Enoxaparin and M-Dalteparin but may apply to future generic products that we pursue. In certain circumstances, a regulatory exclusivity period can extend beyond the life of a patent, and thus block ANDAs from being approved on or after the patent expiration date. For example, the FDA may now extend the exclusivity of a product by six months past the date of patent expiry if the manufacturer undertakes studies on the effect of their product in children, a so-called pediatric extension. The FDA has requested pediatric studies of Lovenox from Aventis. If Aventis undertakes these studies, Lovenox could be eligible for a six month extension of exclusivity.

        Products that are a combination of more than one jurisdictional product type, for example, drug/medical device combinations that are integrated as a whole or combined by copackaging or colabeling, may require more than one product approval, and/or the premarket review and postmarket regulation of more than one center at the FDA, possibly resulting in an uncertain approval path. Development and commercialization of our pulmonary formulations could in some instances require modification of the design or labeling of a legally available medical device, in which case the FDA may regulate the drug and delivery device as a combination product and/or require approval or clearance for the modified device. In addition, to the extent the delivery device is owned by a separate company, that company's cooperation would be required to obtain the necessary changes to the delivery device and any additional clearances or approvals. If no appropriate delivery device is available, we might have to develop and obtain clearance or approval of the delivery device itself. While such a delivery device could be approved as part of an NDA approval, it could also be subject to the medical device premarket submission process, or could be subject to both.

        Diagnostic products like our future sugar-based discovery product for diagnosing prostate cancer would be evaluated as a medical device, either through the PMA process or the premarket notification process, which is also known as the 510(k) clearance process, depending on whether the test is substantially equivalent to a legally marketed device. Gathering clinical evidence for diagnostic devices often does not, but may require submitting an investigational device exemption application to the agency, which in practice requires approval from the FDA within 30 days. Such testing is also subject to IRB approval and oversight. PMA approval requires, among other things, the submission of valid scientific evidence in the form of preclinical and clinical data, and a preapproval inspection to determine if the manufacturing facility complies with cGMP practices under the quality system regulation that governs the design and all elements of the manufacture of devices. To demonstrate substantial equivalence, a 510(k) must show that the device is as safe and effective as an already legally marketed device, or known as a predicate device. The evaluation of the newer device must not raise different questions of safety and effectiveness than that of the predicate device. 510(k)s normally do not, but sometimes do require clinical data for clearance.

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        After regulatory approval of a product is obtained, we are required to comply with a number of post-approval requirements. For example, as a condition of approval of an NDA, BLA or PMA the FDA may require post marketing testing and surveillance to monitor the product's safety or efficacy.

        In addition, holders of an approved NDA, BLA, PMA or ANDA or cleared 510(k) are required to report certain adverse reactions and production problems to the FDA to provide updated safety and efficacy information and to comply with requirements concerning advertising and promotional labeling for their products. Also, quality control and manufacturing procedures must continue to conform to cGMP after approval. The FDA periodically inspects manufacturing facilities to assess compliance with cGMP, which imposes certain procedural, substantive and recordkeeping requirements. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance.

        We use, and will continue to use in at least the near term, third party manufacturers to produce our products in clinical and commercial quantities. Future FDA inspections may identify compliance issues at our facilities or at the facilities of our contract manufacturers that may disrupt production or distribution or require substantial resources to correct. In addition, discovery of problems with a product or the failure to comply with applicable requirements may result in restrictions on a product, manufacturer or holder of an approved NDA, BLA, PMA, or ANDA or cleared 510(k), including withdrawal or recall of the product from the market or other voluntary FDA-initiated or judicial action that could delay or prohibit future marketing. Also, new government requirements may be established that could delay or prevent regulatory approval of our products under development.

        The Hatch-Waxman Act provides incentives for generic pharmaceutical manufacturers to challenge patents on branded pharmaceutical products and/or their methods of use, as well as to develop products comprising non-infringing forms of the patented drugs. The Hatch-Waxman legislation places significant burdens on the ANDA filer to ensure that such challenges are not frivolous, but also offers the opportunity for significant financial reward if the challenge is successful.

        If there is a patent listed for the branded drug in FDA's Orange Book at the time of submission of the ANDA or at any time before the ANDA is approved and the generic company intends to market the generic equivalent prior to the expiration of that patent, the generic company includes a certification asserting that the patent is invalid, unenforceable and/or not infringed, a so-called "paragraph IV certification."

        After receiving notice from the FDA that its application is acceptable for review or immediately if the ANDA has been amended to include a paragraph IV certification after the application was submitted to the FDA, the company filing a generic application is required to send the patent holder and the holder of the NDA for the brand-name drug a notice explaining why it believes that the patents in question are invalid, unenforceable or not infringed. Upon receipt of the notice from the generic applicant, the patent holder has 45 days during which to bring a patent infringement suit in federal district court against the generic applicant in order to obtain the 30 month automatic stay.

        If a suit is commenced by the patent holder during the 45 day period, the Hatch-Waxman Act provides for an automatic stay on the FDA's ability to grant final approval of the ANDA for the generic product. Patent holders may only obtain one 30 month stay with respect to patents that were listed at the time an ANDA was filed. The period during which the FDA may not approve the ANDA and the patent challenger therefore may not market the generic product is 30 months, or such other period as may be ordered by the court. The 30-month period may or may not, and often does not, coincide with the timing of the resolution of the lawsuit or the expiration of a patent, but if the patent

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challenge is successful or the challenged patent expires during the 30-month period, the FDA may approve the generic drug for marketing, assuming there are no other obstacles to approval such as periods of non-patent exclusivity given to the NDA holder.

        Under the Hatch-Waxman Act, any developer of a generic drug that is considered first to have its ANDA accepted for review by the FDA, and whose filing includes a paragraph IV certification, may be eligible to receive a 180-day period of generic market exclusivity. This period of market exclusivity may provide the patent challenger with the opportunity to earn a return on the risks taken and its legal and development costs and to build its market share before other generic competitors can enter the market. If the ANDA of the first applicant accepted for filing is withdrawn, the 180-day exclusivity period is forfeited and unavailable to any other applicant. The Medicare Prescription Drug Improvement and Modernization Act of 2003 provides for the elimination of the 180 day exclusivity period if, among other reasons, the company that is first to submit an ANDA does not receive tentative approval from the FDA within 30 months after acceptance for filing of the ANDA submission. However, neither Teva nor Amphastar will be subject to that forfeiture provision because it is not retroactive.

Foreign Regulation

        In addition to regulations in the United States, we will be subject to a variety of foreign regulations governing clinical trials and commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we must obtain approval of a product by the comparable regulatory authorities of foreign countries before we can commence clinical trials or marketing of the product in those countries. The approval process varies from country to country, and the time may be longer or shorter than that required for FDA approval. The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from country to country.

        Under European Union regulatory systems, we may submit marketing authorizations either under a centralized or decentralized procedure. The centralized procedure provides for the grant of a single marketing authorization that is valid for all European Union member states. The decentralized procedure provides for mutual recognition of national approval decisions. Under this procedure, the holder of a national marketing authorization may submit an application to the remaining member states. Within 90 days of receiving the applications and assessment report, each member state must decide whether to recognize approval.

Related Matters

        From time to time, legislation is drafted, introduced and passed in Congress that could significantly change the statutory provisions governing the approval, manufacturing and marketing of products regulated by the FDA. In addition, FDA regulations and guidance are often revised or reinterpreted by the agency in ways that may significantly affect our business and our products. It is impossible to predict whether legislative changes will be enacted, or FDA regulations, guidance or interpretations changed, or what the impact of such changes, if any, may be.

Lovenox Regulatory and Legal Matters

        On February 19, 2003, a Citizen Petition was submitted to FDA on behalf of Aventis to request that the FDA withhold approval of any ANDA for a generic version of Lovenox until the conditions set forth in the petition are satisfied. In its petition, Aventis principally requested that until enoxaparin has been "fully characterized," the FDA refrain from approving any ANDA citing Lovenox as the reference listed drug until the manufacturing process used to create the generic product is determined to be equivalent to Aventis' manufacturing process for enoxaparin or the application is supported by proof of equivalent safety and effectiveness demonstrated through clinical trials. To date, however, the FDA has not publicly responded to Aventis' Citizen Petition.

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        Companies that produce branded pharmaceutical products routinely bring litigation against generic applicants seeking FDA approval to manufacture and market generic forms of their branded products prior to the expiry of patents listed in the Orange Book. These companies typically allege patent infringement as the basis for filing suit against a generic applicant.

        On May 7, 2003, Aventis filed a re-issue application for the '618 patent in the United States Patent and Trademark Office. The inventor declared the original patent to be partly inoperative by reason of a defective specification. The patent will remain in force as a granted patent during the reissue proceeding. Aventis has stated that if the application is approved, Aventis believes that the '618 patent could be re-issued prior to year end 2004.

        In June 2003, Aventis announced that it received notices from Amphastar and independently from Teva that ANDAs had been filed by each company with the FDA with a paragraph IV certification against the '618 patent seeking authorization to produce and market a generic version of Lovenox in the United States.

        In August 2003, Aventis sued Amphastar and Teva in two different United States District Courts: New Jersey and in the Central District of California. Amphastar and Teva assert non-infringement and invalidity of the '618 patent and have also sought related declaratory judgment relief. In February 2004, the New Jersey case was ordered to be transferred to the Central District of California, where the court has set a discovery schedule and a trial date of April 2005.

        A November 2003 preliminary amendment by Aventis shows that the specification of the '618 patent was amended and that one claim was cancelled. In the Preliminary Amendment, Aventis maintained the validity of the remaining claims of the '618 patent over, among other things, the arguments raised in the notice letters provided by Amphastar and Teva.

        In April 2004, Aventis stated in a press release that it had received an official preliminary response from the United States Patent and Trademark Office rejecting its re-issue application for the '618 patent. Aventis has responded to this initial rejection of its re-issue application and stated its belief that if the application is ultimately approved, the '618 patent could be re-issued prior to year-end 2004.

        We intend to explore all available legal and regulatory options to gain approval for and market our generic enoxaparin product prior to expiration of the '618 patent. If and when we attempt to commercialize M-Enoxaparin, we expect to face significant litigation from Aventis.

        Depending upon a thorough analysis of a variety of legal and commercial factors, our collaborator, Sandoz, may, in certain circumstances, upon expiration of the 30-month automatic stay on the FDA's ability to grant approval of an ANDA, elect to market M-Enoxaparin, if approved, even though litigation is still pending. This could be before any court decision is rendered or while an appeal of a lower court decision is pending. Should we elect to proceed in this manner, we could face substantial patent liability damages if the final court decision is adverse to us. With certain exceptions, Sandoz will indemnify us for any losses we may incur or must pay to a third party which may result from patent infringement litigation by Aventis and certain other claims. Litigation often involves significant expense or may delay or prevent introduction of M-Enoxaparin. If we are not successful in commercializing M-Enoxaparin, or if we are significantly delayed in doing so, our business will be materially harmed.

Hazardous Materials

        Our research and development processes involve the controlled use of hazardous materials and chemicals, including sodium azide, cetylpyridinium chloride monohydrate, 4-chlorobenzyl chloride, sodium nitrite pyridine, sodium cyanoborohydride and barium acetate. We are subject to federal, state and local laws and regulations governing the use, manufacture, storage, handling and disposal of hazardous materials and waste products. We do not expect the cost of complying with these laws and regulations to be material.

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Employees

        We believe that our success will depend greatly on our ability to identify, attract and retain capable employees. As of April 30, 2004, we had 36 employees, including a total of 14 employees who hold M.D. or Ph.D. degrees. Our employees are not represented by any collective bargaining unit, and we believe our relations with our employees are good.

Facilities

        As of March 31, 2004, we leased a total of approximately 13,900 square feet of office and laboratory space. Our leased properties are described below:

Property Location

  Approximate Square Footage
  Use
  Lease Expiration Date
43 Moulton Street
Cambridge, Massachusetts 02138
  5,300   Laboratory & Office   08/31/2004

68 Moulton Street
Cambridge, Massachusetts 02138

 

8,600

 

Office

 

08/31/2004

        We have signed a non-binding letter of intent with a third party to enter into a ten year lease for approximately 24,000 square feet of office and laboratory space in Cambridge, Massachusetts, scheduled to commence on September 1, 2004.

Legal Proceedings

        We are currently not a party to any material legal proceedings.

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MANAGEMENT

        Our executive officers, directors and other significant employee, and their ages and positions as of April 30, 2004, are set forth below:

Name

  Age
  Position
Executive Officers and Directors        
Alan L. Crane   40   Chairman of the Board, President and Chief Executive Officer
Steven B. Brugger   45   Vice President, Strategic Product Development
Richard P. Shea   52   Vice President and Chief Financial Officer
Joseph E. Tyler   54   Vice President, Manufacturing
Ganesh Venkataraman, Ph.D.   37   Co-Founder and Vice President, Technology
Susan K. Whoriskey, Ph.D.   45   Vice President, Licensing and Business Development
Peter Barrett, Ph.D.(2)(3)   50   Director
John K. Clarke(1)   50   Director
Peter Barton Hutt, LL.B., LL.M.(2)   69   Director
Robert S. Langer, Jr., Sc.D.   55   Co-Founder and Director
Stephen T. Reeders, D.M., MRCP(1)   50   Director
Ram Sasisekharan, Ph.D.   39   Co-Founder and Director
Bennett M. Shapiro, M.D.(3)   64   Director
Christoph H. Westphal, M.D., Ph.D.(2)(3)   36   Co-Founder and Director
John L. Zabriskie, Ph.D.(1)   64   Director
Significant Employee        
Ian D. Fier   37   Senior Director, Development Operations

(1)
Member of Audit Committee

(2)
Member of Nominating and Corporate Governance Committee

(3)
Member of Compensation Committee

         Alan L. Crane has been a director since June 2001 and our Chairman of the Board, President and Chief Executive Officer on a full-time basis since May 2002. From February 1997 to May 2002, Mr. Crane held various management positions at Millennium Pharmaceuticals, Inc., a biopharmaceutical company. He most recently served as Senior Vice President, Global Corporate Development, where he led Millennium's strategic alliance, mergers and acquisitions and licensing activities. Mr. Crane serves on the boards of the following privately held companies: Compound Therapeutics, Inc., Vaccinex, Inc. and Control Delivery Systems, Inc. Mr. Crane serves as a venture partner at Polaris Venture Partners, a venture capital firm, and as a Member of the Board of Overseers of Children's Hospital Boston, a not for profit teaching affiliate of Harvard Medical School. Mr. Crane received his B.A. in Biology, summa cum laude , from Harvard College and both his M.A. in Biology and M.B.A. in General Management from Harvard University.

         Steven B. Brugger has been our Vice President, Strategic Product Development since August 2002. From October 1999 to August 2002, Mr. Brugger served as a Vice President for Millennium Pharmaceuticals, Inc., a biopharmaceutical company, where he built Millennium's strategic marketing, project management and portfolio management capabilities. During his tenure at Millennium, Mr. Brugger served as Head of Commercial Development, General Manager of the Inflammation and Metabolic Business Units, and Development Projects Leader for the Aventis and Abbott collaborations. From 1984 to October 1999, Mr. Brugger worked at Novartis Pharmaceuticals, a pharmaceutical company, most recently serving as Executive Director of Marketing for the Transplant, Tissue

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Engineering, and Immunology Business Unit. Mr. Brugger received his B.A. in Biology from Susquehanna University and his M.B.A. from Rutgers University.

         Richard P. Shea has been our Vice President and Chief Financial Officer since October 2003. From April 2002 to April 2003, Mr. Shea served as Chief Operating Officer for Variagenics, Inc., a pharmacogenomics company. From March 2000 to April 2002, Mr. Shea served as Variagenics' Chief Financial Officer, and from February 1999 to March 2000, he served as its Vice President, Finance and Administration. While at Variagenics, Mr. Shea was responsible for finance, legal, investor relations, human resources and operations. From April 1997 to January 1999, Mr. Shea was at Genetics Institute, where he served as Vice President of Finance, and from October 1992 to April 1997 he served as its Controller. Mr. Shea is a CPA and received his A.B. from Princeton University and his M.B.A. with High Honors from Boston University.

         Joseph E. Tyler has been our Vice President, Manufacturing since November 2002. From April 2001 to November 2002, Mr. Tyler served as Vice President of Operations for Salix Pharmaceuticals, Inc., a pharmaceutical company, where he led activities for commercial operations and new product manufacturing development. From April 1995 to March 2001, Mr. Tyler served as Vice President of Manufacturing at GelTex Pharmaceuticals, Inc., a pharmaceutical company, where he managed contract manufacturing from bulk supply to drug product for four novel synthetic polymeric oral drugs. Mr. Tyler received his B.S. in Chemical Engineering from Carnegie Mellon University and his M.S. in Biochemical Engineering from Cornell University.

         Ganesh Venkataraman, Ph.D. is a co-founder of our company and has been our Vice President, Technology since January 2002. From August 2000 to January 2003, Dr. Venkataraman served as the Director of Bioinformatics for the Consortium for Functional Glycomics, a multi-million dollar NIH initiative to study the role of complex sugars in biology. From March 1995 to July 2000, Dr. Venkataraman was a research faculty member at the Harvard-M.I.T. division of Health and Sciences and Technology, where he investigated the biochemistry and biophysics of carbohydrates and research in the area of analytical techniques for complex carbohydrates. Dr. Venkataraman received his M.S. and Ph.D. in Chemical Engineering from the Massachusetts Institute of Technology.

         Susan K. Whoriskey, Ph.D. has been our Vice President, Licensing and Business Development since January 2002. From September 2001 to January 2002, Dr. Whoriskey was a biotechnology consultant to Polaris Venture Partners, a venture capital firm, where she implemented the business operations of Momenta upon the receipt of seed funding and assisted in recruiting team members. From September 1993 to May 2001, Dr. Whoriskey held various management positions at Cubist Pharmaceuticals, Inc., a biopharmaceutical company. Most recently she served as Senior Director of Licensing. As a founding employee she helped recruit management team members, was involved in multiple fundraising rounds, including taking the company public in 1996, and was involved in negotiating numerous pharmaceutical collaborations. Dr. Whoriskey received her B.S. in Microbiology from the University of Massachusetts and her Ph.D. in Molecular Biology from the University of California, Los Angeles. Dr. Whoriskey did a post-doctoral fellowship with a Chemistry emphasis at Harvard University.

         Peter Barrett, Ph.D. has been a director since May 2003. Dr. Barrett has served as a Senior Partner of Atlas Venture, a venture capital firm, since January 2002. From August 1998 to December 2001, he served as Executive Vice President and Chief Business Officer of Celera Genomics, a biopharmaceutical company, which he co-founded. He also served as Vice President of Celera from 1994 to 1998. Dr. Barrett received his B.S. in Chemistry from Lowell Technological Institute (now known as the University of Massachusetts, Lowell) and his Ph.D. in Analytical Chemistry from Northeastern University. He also completed Harvard Business School's Management Development Program.

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         John K. Clarke has been a director since April 2002. Mr. Clarke founded Cardinal Partners, a venture capital firm, in 1997 and has served as the Managing General Partner since 1997. He has founded and served as interim Chief Executive Officer of a number of portfolio companies, including Alkermes, Inc., Arris Pharmaceuticals, Inc., the DNX Corporation and Cubist Pharmaceuticals, Inc. Mr. Clarke is a member of the board of directors of Cubist Pharmaceuticals, Inc. He received his B.A. in Biology and Economics from Harvard College and his M.B.A. from the Wharton School of the University of Pennsylvania.

         Peter Barton Hutt, LL.B., LL.M. has been a director since June 2001. Mr. Hutt has been a partner at the law firm of Covington & Burling and has been an attorney at the firm since 1975. He served as former Chief Counsel for the Food and Drug Administration from 1971 to 1975. Mr. Hutt is a member of the Institute of Medicine of the National Academy of Sciences and teaches a course on Food and Drug Law each Winter Term at Harvard Law School. He has co-authored the casebook used to teach Food and Drug Law and has published numerous papers on food and drug law and health policy. Mr. Hutt is a member of the board of directors of CV Therapeutics, Inc. and several private life sciences companies. Mr. Hutt received his B.A., magna cum laude , from Yale University, his LL.B. from Harvard University and his LL.M. from New York University.

         Robert S. Langer, Jr., Sc.D. is a co-founder of our company and has been a director since May 2001. Dr. Langer is the Kenneth J. Germeshausen Professor of Chemical and Biomedical Engineering at the Massachusetts Institute of Technology and has been on the faculty of M.I.T. since 1977. Dr. Langer is the former Chairman of the Food and Drug Administration Science Board, the FDA's highest advisory board. He has written 780 articles, 450 abstracts and has over 500 issued or pending patents. Dr. Langer has received over 100 major awards, including the 2002 Charles Stark Draper Prize, considered the world's most prestigious engineering prize and the engineering-equivalent of the Nobel Prize. Dr. Langer is a member of the board of directors of Wyeth, Sontra Medical Corporation and Boston Life Sciences, Inc. Dr. Langer received his B.S. from Cornell University and his Sc.D. from the Massachusetts Institute of Technology, both in Chemical Engineering.

         Stephen T. Reeders, D.M., MRCP has been a director since May 2003. Dr. Reeders is founder and Chief Executive Officer of MVM Limited, a venture capital firm. He has served as the Chief Executive Officer of MVM Limited since June 1997. In this role, he has co-founded three biotechnology companies and is a member of the board of directors of Nova Science Limited, Vasca Inc. and Oxxon Pharmaceuticals, Inc. Prior to founding MVM, Dr. Reeders led healthcare investing at Saunders, Karp & Megrue, a venture capital firm, and served on the faculty of Yale University.

         Ram Sasisekharan, Ph.D. is a co-founder of our company and has been a director since May 2001. Dr. Sasisekharan has been a Professor of Biological Engineering at the Massachusetts Institute of Technology since 1996. Dr. Sasisekharan's research on complex polysaccharides has led to over 90 publications and over 30 patents, including the core technologies of Momenta. He has won both the Burroughs Wellcome and Beckman Foundation Young Investigator Awards and was the recipient of 1998, 1999, 2000 and 2001 CaPCure Awards from the CaPCure Foundation. Dr. Sasisekharan serves on the steering committee of the Consortium for Functional Glycomics. Dr. Sasisekharan received his Ph.D. in Medical Sciences from Harvard Medical School.

         Bennett M. Shapiro, M.D. has been a director since May 2003. From September 1990 to July 2003, Dr. Shapiro served as an Executive Vice President of Merck & Co., Inc., a research-based pharmaceutical company. Dr. Shapiro is the former head of Worldwide Licensing and External Research at Merck; prior to that he served as the head of Basic and Preclinical Research at Merck & Co. and as Chairman of the Biochemistry department at the University of Washington. Dr. Shapiro received his B.S. in Chemistry from Dickinson College and his M.D. from Jefferson Medical College.

         Christoph H. Westphal, M.D., Ph.D. is a co-founder and was founding Chief Executive Officer and Vice Chairman of our company and has been a director since May 2001. Dr. Westphal has served as

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the General Partner of Polaris Venture Partners, a venture capital firm, since June 2000. From July 1998 to June 2000, Dr. Westphal was a consultant at McKinsey & Co., a management consulting firm. Dr. Westphal is a member of the board of directors of Acceleron Pharma, Athenix Corporation, Saegis Pharmaceuticals, Inc., Hydra Biosciences, Inc. and Alnylam Pharmaceuticals, Inc. and is also a founder of Nanosys, Inc., among others. Dr. Westphal also founded and was Vice Chairman and founding Chief Executive Officer of Alnylam Pharmaceuticals, Inc. and Acceleron Pharma. Dr. Westphal completed his Abitur at the Deutsche Schule Washington, his B.A., summa cum laude , at Columbia University, and his M.D./Ph.D. at Harvard Medical School.

         John L. Zabriskie, Ph.D. has been a director since June 2001. Dr. Zabriskie is a co-founder of PureTech Ventures, a life science venture creation and business development organization, and has served as its General Partner since April 2001. From July 1997 to August 2000, Dr. Zabriskie served as Chairman and Chief Executive Officer of NEN Life Science Products, Inc., a supplier of radioactive, chemilluminescent and fluorescent labeling and detection products for life science research and drug discovery. Prior to that, Dr. Zabriskie was President and Chief Executive Officer of Pharmacia and UpJohn, Inc. and an Executive Vice President at Merck & Co. Dr. Zabriskie is a member of the board of directors of BioSource International, Inc., Array Biopharma, Inc., MacroChem Corporation and Kellogg Company. Dr. Zabriskie received his B.S. in Chemistry from Dartmouth College and his Ph.D. in Organic Chemistry from the University of Rochester.

         Ian D. Fier has been our Senior Director, Development Operations since October 2002. From October 2001 to October 2002, Mr. Fier served as Vice President of Clinical Affairs for BioTransplant Incorporated, a biotechnology company, where he led the clinical development activities for both antibody based therapeutics and medical devices. From September 1997 to October 2001, Mr. Fier served as Senior Director, Product Development at The Medicines Company, a specialty pharmaceutical company focused on acute care products, where he built the development organization and managed the clinical development of bivalirudin (Angiomax®) through regulatory approval. In this role, he was responsible for managing several large clinical trials in acute coronary syndromes. Mr. Fier received his B.S. in Psychology (Biological) from Tufts University and his M.B.A. and Certificate in Health Care Management from Boston University.

Board Composition

        Upon the completion of this offering, our board of directors will consist of ten members. In accordance with the terms of our certificate of incorporation and by-laws, which will become effective upon completion of this offering, the board of directors will be divided into three classes, class I, class II and class III, with each class serving staggered three-year terms. Upon the completion of this offering, the members of the classes will be divided as follows:

    the class I directors will be Alan L. Crane, Peter Barton Hutt and Christoph H. Westphal, and their term will expire at the annual meeting of stockholders to be held in 2005;

    the class II directors will be John K. Clarke, Robert S. Langer, Jr. and Stephen T. Reeders, and their term will expire at the annual meeting of stockholders to be held in 2006; and

    the class III directors will be Peter Barrett, Ram Sasisekharan, Bennett M. Shapiro and John L. Zabriskie, and their term will expire at the annual meeting of stockholders to be held in 2007.

        Our certificate of incorporation that will become effective upon the completion of this offering provides that the authorized number of directors may be changed only by resolution of the board of directors. Any additional directorships resulting from an increase in the number of directors will be distributed between the three classes so that, as nearly as possible, each class will consist of one-third of the directors. This classification of the board of directors may have the effect of delaying or preventing changes in the control or management of Momenta.

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        Our directors may be removed only for cause by the affirmative vote of the holders of 75% or more of our voting stock.

Board Committees

        Our board of directors has established an audit committee, a compensation committee and a nominating and corporate governance committee. The members of each committee are appointed by the board of directors and serve one-year terms .

        Audit Committee.     We have an audit committee consisting of John K. Clarke, Stephen T. Reeders and John L. Zabriskie. John L. Zabriskie chairs the committee. The audit committee assists our board of directors in its oversight of:

    the integrity of our financial statements;

    the independent auditor's qualifications and independence; and

    the performance of our independent auditors.

        The audit committee has the sole and direct responsibility for appointing, evaluating and retaining our independent auditors and for overseeing their work. All audit services to be provided to us and all non-audit services, other than de minimis non-audit services, to be provided to us by our independent auditors must be approved in advance by our audit committee. We believe that each member of the audit committee satisfies the requirements for membership established by the NASDAQ National Market and the Securities and Exchange Commission. In particular, our board of directors has determined that, although Mr. Reeders falls outside the safe harbor provisions of Rule 10A-3(e)(1)(ii) under the Securities Exchange Act of 1934, as amended, Mr. Reeders nevertheless meets the independence requirements contemplated by Rule 10A-3 under the Exchange Act. The safe harbor provisions of Rule 10A-3(e)(1)(ii) exempt holders of 10% or less of any class of voting securities of an issuer from being deemed to be in control of, or an affiliate of, that issuer. After this offering, Mr. Reeders will beneficially own approximately 11% of our outstanding common stock as result of his affiliation with MVM International Life Sciences Fund No. 1 L.P., a purchaser of shares of our Series B convertible preferred stock and Series C convertible preferred stock. The existence of the safe harbor set forth in Rule 10A-3(e)(1)(ii), however, does not create a presumption in any way that a person exceeding the 10% threshold controls or is otherwise an affiliate of an issuer, and our board of directors, after considering Mr. Reeders' individual ownership in our outstanding common stock and his service to us solely in the capacity as a director, has determined that Mr. Reeders satisfies the audit committee membership requirements established by each of the NASDAQ National Market and the Securities and Exchange Commission.

        Compensation Committee.     We have a compensation committee consisting of Peter Barrett, Bennett M. Shapiro and Christoph H. Westphal. Peter Barrett chairs the committee. The purpose of our compensation committee is to discharge the responsibilities of our board of directors relating to compensation of our executive officers. Specific responsibilities of our compensation committee include:

    reviewing and recommending approval of compensation of our executive officers;

    administering our stock incentive and employee stock purchase plans; and

    reviewing and making recommendations to our board with respect to incentive compensation and equity plans.

        We believe that each member of the compensation committee satisfies the requirements for membership established by the NASDAQ National Market.

        Nominating and Corporate Governance Committee.     We have a nominating and corporate governance committee consisting of Peter Barrett, Peter Barton Hutt and Christoph H. Westphal. Peter

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Barton Hutt chairs the committee. The purpose of the nominating and corporate governance committee is to:

    identify and recommend nominees for election to our board of directors;

    review and assess the adequacy of our corporate governance principles and recommend any proposed changes to our board of directors; and

    oversee the evaluation of our board.

        We believe that each member of the nominating and corporate governance committee satisfies the requirements for membership established by the NASDAQ National Market.

Director Compensation

        We reimburse each member of our board of directors who is not a company employee for reasonable travel and other expenses in connection with attending meetings of the board of directors.

        We have granted the following stock options under our 2002 stock incentive plan to our non-employee directors:

Name of Director

  Number of Shares
  Date of Grant
Peter Barton Hutt(1)   51,200   8/1/02
Peter Barton Hutt(2)   6,400   9/18/02
Peter Barton Hutt(3)   6,400   9/10/03
Bennett M. Shapiro(1)   81,200   2/5/03
John L. Zabriskie(1)   51,200   8/1/02

(1)
Twenty-five percent of the shares subject to each option vested on the first anniversary of the date of grant and the remaining shares vest at a rate of 25% annually.

(2)
This option was granted as compensation for consulting services pursuant to a consulting agreement between Mr. Hutt and us. Two thousand eighty-three shares vested on the date of grant and an additional 1/12th of the shares subject to the option vested monthly thereafter.

(3)
This option was granted as compensation for consulting services pursuant to a consulting agreement between Mr. Hutt and us. Four hundred sixteen shares vested on the the date of grant and an additional 1/12th of the shares subject to the option vest monthly thereafter.

        In April 2004, our board of directors approved a program under our 2004 stock incentive plan in which each non-employee director will automatically receive an option to purchase no more than 38,400 shares of our common stock upon his or her appointment to our board of directors. These options shall vest to the extent of one-third of the shares on each of the first, second and third anniversaries of the grant date, subject to the non-employee director's continued service as a director. Subject to an annual evaluation, which evaluation shall be overseen by our Nominating and Corporate Governance Committee, each non-employee director will automatically receive an annual grant of an option to purchase no more than 19,200 shares of our common stock at each year's annual meeting after which he or she will continue to serve as a director. These options will vest on the first anniversary of the grant date, subject to the non-employee director's continued service as a director. Each non-employee director stock option will terminate on the earlier of ten years from the date of grant and three months after the recipient ceases to serve as a director, except in the case of death or disability, in which event the option will terminate three months from the date of the director's death or disability. The exercise price of all of these options will equal the fair market value of our common stock on the date of grant.

Compensation Committee Interlocks and Insider Participation

        None of our executive officers serves as a member of the board of directors or compensation committee, or other committee serving an equivalent function, or of any other entity that has one or more of its executive officers serving as a member of our board of directors or compensation committee. None of the members of our compensation committee has ever been our employee.

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Scientific Advisory Board

        We seek advice from a number of leading scientists and physicians on scientific and medical matters. Our scientific advisory board regularly assesses:

    our research and development programs;

    the design and implementation of our clinical programs;

    our patent and publication strategies;

    new technologies relevant to our research and development programs; and

    specific scientific and technical issues relevant to our business.

        The current members of our scientific advisory board are:

Name

  Professional Affiliation
Elliott Antman, M.D.   Director of Cardiac Unit, Brigham and Women's Hospital

K. Frank Austen, M.D.

 

Director of Inflammation and Allergic Diseases, Brigham and Women's Hospital; Professor of Medicine, Harvard Medical School

Carolyn R. Bertozzi, Ph.D.

 

Professor, University of California, Berkeley and Department Head of Lawrence Berkeley National Laboratory

Eugene Braunwald, M.D.

 

Brigham and Women's Hospital; Distinguished Hersey Professor of Medicine, Harvard Medical School; Founder and Chairman, TIMI Study Group

Frank Bullock, Ph.D.

 

Former Senior Vice President of Research, Schering-Plough Corporation

Benito Casu, Ph.D.

 

Scientific Coordinator, Ronzoni Institute for Chemical and Biochemical Research

M. Judah Folkman, M.D.

 

Director of Surgical Research Laboratory, Children's Hospital Boston; Professor of Pediatric Surgery, Harvard Medical School

Robert S. Langer, Jr., Sc.D.

 

Co-Founder of Momenta; Kenneth J. Germeshausen Professor of Chemical and Biomedical Engineering, M.I.T.

Phillips W. Robbins, Ph.D.

 

Professor of Molecular and Cell Biology, Boston University Medical School

Ram Sasisekharan, Ph.D.

 

Co-Founder of Momenta; Professor of Biological Engineering, M.I.T.

Regulatory Advisory Board

        We seek advice from a number of leading professionals on regulatory matters. Our regulatory advisory board frequently provides advice on our proposed INDs, ANDAs and other regulatory filings. Our regulatory advisory board members also provide guidance on our communications and correspondence with regulatory agencies.

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        The current members of our regulatory advisory board are:

Name

  Professional Affiliation
Richard Cooper, J.D.   Williams & Connolly LLP; Former Chief Counsel, FDA

J. Richard Crout, M.D.

 

Former Director, Center for Drug Evaluation and Research

Thomas Q. Garvey, III, M.D.

 

Former Supervisory Medical Officer, Center for Drug Evaluation and Research

Peter Barton Hutt, LL.B., LL.M.

 

Covington & Burling; Former Chief Counsel, FDA

Robert W. Pollock

 

Lachman Consultant Services, Inc.; Former Deputy Director, Office of Generic Drugs, FDA

Executive Compensation

        The table below sets forth the total compensation paid or accrued for the fiscal year ended December 31, 2003 for our chief executive officer and each of our four most highly compensated other executive officers who were serving as executive officers on December 31, 2003 and whose total annual compensation exceeded $100,000 for the year ended December 31, 2003. We refer to these officers as our named executive officers.

Summary Compensation Table

 
   
   
  Long-Term
Compensation Awards

 
  Annual Compensation
Name and Principal Position

  Securities
Underlying
Options (#)

  Salary
  Bonus
Alan L. Crane
Chairman, President and Chief Executive Officer
  $ 330,555   $ 15,000   188,800
Steven B. Brugger
Vice President, Strategic Product Development
    220,375     17,500   51,200
Joseph E. Tyler
Vice President, Manufacturing
    210,000     30,000   32,000
Susan K. Whoriskey
Vice President, Licensing and Business Development
    166,500     25,000   32,000
Ganesh Venkataraman
Vice President, Technology
    165,000     51,250   32,000


Option Grants in Last Fiscal Year

        The following table contains information regarding grants of options to purchase shares of our common stock to our named executive officers during the year ended December 31, 2003. The potential realizable value set forth in the last column of the table is calculated based on the term of the option at the time of grant, which is ten years. This value is based on assumed rates of stock price appreciation of 5% and 10% compounded annually from the date of grant until their expiration date, assuming a fair market value equal to an assumed initial public offering price of $14.00, minus the applicable exercise price. These numbers are calculated based on the requirements of the Securities and Exchange Commission and do not reflect our estimate of future stock price growth. Actual gains, if

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any, on stock option exercises will depend on the future performance of the common stock on the date on which the options are exercised.

 
  Number of Securities Underlying Options Granted(#)(1)
  Percent of Total Options Granted to Employees in Fiscal Year(3)
   
   
  Potential Realizable
Value at Assumed Annual Rates of Stock Price Appreciation for Option Term(5)

Name

  Exercise Price per Share(4)
   
  Expiration Date
  5% ($)
  10% ($)
Alan L. Crane   128,000
60,800

(2)
25.7
12.2
%
$
0.231
0.61
  06/10/2013
10/31/2013
  $
2,889,411
1,349,427
  $
4,618,418
2,170,706
Steven B. Brugger   51,200   10.3     0.231   05/28/2013     1,155,764     1,847,367
Joseph E. Tyler   32,000   6.4     0.231   05/28/2013     722,353     1,154,605
Susan K. Whoriskey   32,000   6.4     0.231   05/28/2013     722,353     1,154,605
Ganesh Venkataraman   32,000   6.4     0.231   05/28/2013     722,353     1,154,605

(1)
Stock options granted to our named executive officers generally vest as to 25% of the shares on the first anniversary of the date of grant and an additional 6.25% of the shares vest at the end of each three-month period thereafter. See also footnote 2 below.

(2)
On February 1, 2004, this option began to vest in 16 equal quarterly installments.

(3)
Based on an aggregate of 498,355 shares subject to options granted to our employees in 2003, including the named executive officers.

(4)
The exercise price per share was determined to be equal to the fair market value per share of our common stock as valued by our board of directors on the date of grant.

(5)
Amounts represent hypothetical gains that could be achieved for stock options if exercised at the end of the option term. These gains are based on assumed rates of stock price appreciation of 5% and 10% compounded annually from the date stock options are granted. Actual gains, if any, on stock option exercises will depend on the future performance of our common stock on the date on which the stock options are exercised.

Fiscal Year-End Option Values

        The following table sets forth information for each of the named executive officers regarding the number of shares subject to both exercisable and unexercisable stock options, as well as the value of unexercised in-the-money options, as of December 31, 2003. There was no public trading market for our common stock as of December 31, 2003. Accordingly, we have calculated the value of the unexercised in-the-money options at fiscal year-end on the basis of an assumed fair market value of our common stock as of December 31, 2003 equal to the assumed initial public offering price of $14.00 per

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share, less the aggregate exercise price. None of the named executive officers exercised options during the fiscal year ended December 31, 2003.

 
  Number of Securities Underlying
Unexercised Options at
December 31, 2003

  Value of Unexercised
In-The-Money Options at
December 31, 2003

Name

  Exercisable
  Unexercisable
  Exercisable
  Unexercisable
Alan L. Crane  
  128,000
60,800
 
  1,762,432
814,112
Steven B. Brugger   27,200   111,040   374,544   1,528,970
Joseph E. Tyler   22,400   99,200   308,448   1,365,952
Susan K. Whoriskey     32,000     440,608
Ganesh Venkataraman     32,000     440,608

Employment Arrangements

        Alan L. Crane.     We entered into an employment agreement with Mr. Crane, our Chairman of the Board, President and Chief Executive Officer, dated March 15, 2002. Pursuant to this agreement, Mr. Crane currently receives an annual base salary of $370,000, subject to annual increases upon review by the compensation committee of our board of directors. In connection with the execution of the agreement, we paid Mr. Crane a bonus of $106,585 on March 15, 2002.

        Under the agreement, either we or Mr. Crane may terminate his employment at any time, subject to continuation of salary payment and benefits for one year if we terminate Mr. Crane's employment without cause or Mr. Crane terminates his employment for good reason. If, however, Mr. Crane commences full-time employment or enters into a consulting arrangement during the period of time for which we are providing severance benefits to Mr. Crane, then our cash severance payments to Mr. Crane will be reduced by the amount of any cash compensation Mr. Crane earns in his new employment or consulting arrangement. In addition, we will have no obligation to provide for benefits so long as the quality of the benefits provided by the new employer are equivalent or superior to the benefits provided by us.

        In connection with the execution of a restricted stock agreement dated March 15, 2002, Mr. Crane purchased 980,858 shares of restricted common stock for an aggregate purchase price of $106,662. Subject to certain vesting conditions, the 980,858 shares of restricted common stock are subject to a repurchase right by us at a per share price of $0.13. Mr. Crane agreed to pay the purchase price to us in three installments on each of January 1, 2003, January 1, 2004 and January 1, 2005.

        Susan K. Whoriskey.     We entered into an employment agreement with Dr. Whoriskey, our Vice President, Licensing and Business Development, dated April 10, 2002. Pursuant to this agreement, Dr. Whoriskey currently receives an annual base salary of $180,000, subject to increases upon review at least once every six months.

        Under the agreement, either we or Dr. Whoriskey may terminate her employment at any time, subject to continuation of salary payment and benefits for three months if we terminate Dr. Whoriskey's employment without cause or Dr. Whoriskey terminates her employment for good reason.

        Ganesh Venkataraman.     We entered into an employment agreement with Dr. Venkataraman, our Vice President, Technology, dated June 13, 2001, which was amended and restated on April 10, 2002. Pursuant to this agreement, Dr. Venkataraman currently receives an annual base salary of $205,000, subject to increases upon review at least once every 12 months.

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        Under the agreement, as amended, either we or Dr. Venkataraman may terminate his employment at any time, subject to continuation of salary payment and benefits for three months if we terminate Dr. Venkataraman's employment without cause or Dr. Venkataraman terminates his employment for good reason.

        Our employment agreements with Mr. Crane, Dr. Whoriskey and Dr. Venkataraman contain nondisclosure, noncompetition and assignment of intellectual property terms. These terms provide for the protection of our confidential information, the transfer of ownership rights to intellectual property developed by such executive officer and a 12-month noncompete provision. Each of our other executive officers has signed our standard form of nondisclosure, noncompetition and assignment of intellectual property agreement, providing for the protection of our confidential information, the transfer of ownership rights to intellectual property developed by such executive officer and an 18-month noncompete provision.

Stock Option and Other Compensation Plans

2002 Stock Incentive Plan

        Our 2002 stock incentive plan was adopted by our board of directors and approved by our stockholders in December 2001. In September 2002 and December 2002, our board of directors and stockholders approved amendments to the 2002 stock incentive plan. The 2002 stock incentive plan, as amended, provides for the grant of incentive stock options, non-statutory stock options and restricted stock awards. A maximum of 1,316,687 shares of common stock are authorized for issuance under our 2002 stock incentive plan.

        In accordance with the terms of the 2002 stock incentive plan, our board of directors has authorized our compensation committee to administer the 2002 stock incentive plan.

        Upon a merger or other reorganization event, our board of directors, or the board of directors of any corporation assuming our obligations, may, in their sole discretion, take any one or more of the following actions pursuant to our 2002 stock incentive plan, as to some or all outstanding options:

    provide that all outstanding options shall be assumed or substituted by the successor corporation;

    terminate all unexercised outstanding options immediately prior to the consummation of such transaction unless exercised by the optionee;

    in the event of a merger pursuant to which holders of our common stock will receive a cash payment for each share surrendered in the merger, make or provide for a cash payment to the optionees equal to the difference between the merger price times the number of shares of our common stock subject to such outstanding options (to the extent then exercisable at prices not in excess of the merger price), and the aggregate exercise price of all such outstanding options, in exchange for the termination of such options; and

    provide that all or any outstanding options shall become exercisable in full immediately prior to such event.

        Pursuant to our 2002 stock incentive plan, upon a merger or other reorganization event, any securities, cash or other property received in exchange for shares of restricted stock shall continue to be governed by the provisions of any restricted stock agreement pursuant to which such restricted stock was issued.

        As of April 30, 2004, there were options to purchase 1,148,900 shares of common stock outstanding under the 2002 stock incentive plan, and 63,111 shares of common stock that had been issued as a result of previously exercised options. After the effective date of the 2004 stock incentive

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plan described below, we will grant no further stock options or other awards under the 2002 stock incentive plan.

2004 Stock Incentive Plan

        Our 2004 stock incentive plan was adopted by our board of directors on March 8, 2004 and approved by our stockholders on June 10, 2004. The 2004 stock incentive plan will become effective on the date that the registration statement of which this prospectus forms a part is declared effective. The 2004 stock incentive plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards and other stock-based awards. Upon effectiveness, 3,948,785 shares of common stock will be reserved for issuance under the 2004 stock incentive plan. In addition, the 2004 stock incentive plan contains an "evergreen provision" which allows for an annual increase in the number of shares available for issuance under the plan on the first day of each of our fiscal years during the period beginning in fiscal year 2005 and ending on the second day of fiscal year 2013. The annual increase in the number of shares shall be equal to the lowest of

    1,974,393 shares;

    5% of our outstanding shares on the first day of the fiscal year; and

    an amount determined by our board of directors.

        Under this provision, no annual increase shall be made to the extent that the number of shares of common stock available for issuance under the 2004 stock incentive plan and all other employee or director equity incentive plans, including our 2004 employee stock purchase plan, would exceed 25% of our outstanding shares on the first day of the applicable fiscal year.

        In accordance with the terms of the 2004 stock incentive plan, our board of directors has authorized our compensation committee to administer the 2004 stock incentive plan. In accordance with the provisions of the 2004 stock incentive plan, our compensation committee will select the recipients of awards and determine:

    the number of shares of common stock covered by options and the dates upon which the options become exercisable;

    the exercise price of options;

    the duration of options;

    the method of payment of the exercise price; and

    the number of shares of common stock subject to any restricted stock or other stock-based awards and the terms and conditions of such awards, including conditions for repurchase, issue price and repurchase price.

        In addition, our board of directors or any committee to which the board of directors delegates authority may, with the consent of the affected plan participants, amend outstanding awards.

        Upon a merger or other reorganization event, our board of directors, may, in their sole discretion, take any one or more of the following actions pursuant to our 2004 stock incentive plan, as to some or all outstanding awards:

    provide that all outstanding awards shall be assumed or substituted by the successor corporation;

    upon written notice to a participant, provide that the participant's unexercised options or awards will become exercisable in full and will terminate immediately prior to the consummation of such transaction unless exercised by the participant;

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    provide that outstanding awards become realizable or deliverable, or restrictions applicable to an award will lapse, in whole or in part, prior to or upon the reorganization event;

    in the event of a merger pursuant to which holders of our common stock will receive a cash payment for each share surrendered in the merger, make or provide for a cash payment to the participants equal to the difference between the merger price times the number of shares of our common stock subject to such outstanding awards (to the extent then exercisable at prices not in excess of the merger price), and the aggregate exercise price of all such outstanding awards, in exchange for the termination of such awards; and

    provide that, in connection with a liquidation or dissolution, awards convert into the right to receive liquidation proceeds.

2004 Employee Stock Purchase Plan

        Our 2004 employee stock purchase plan was adopted by our board of directors on March 8, 2004 and approved by our stockholders on June 10, 2004. The 2004 employee stock purchase plan will become effective on the date that the registration statement of which this prospectus forms a part is declared effective. The plan provides for the issuance of up to 524,652 shares of common stock to participating employees.

        All of our employees, including directors who are employees, and all employees of any participating subsidiaries:

    whose customary employment is more than 20 hours per week for more than five months in a calendar year;

    who were employed by us for at least 90 days prior to enrolling; and

    who are employed on the first day of a designated payroll deduction offering period are eligible to participate in the 2004 employee stock purchase plan.

        Employees who would immediately after the grant of an option under the 2004 employee stock purchase plan own 5% or more of the total combined voting power or value of our stock or the stock of any of our subsidiaries are not eligible to participate in the purchase plan.

        We will make one or more offerings to our employees to purchase stock under the 2004 employee stock purchase plan. Offerings will begin on each February 1, except that our first offering commencement date will begin on the date on which trading of our common stock commences on the NASDAQ National Market in connection with this offering. Each offering commencement date will begin a twelve-month period during which payroll deductions will be made and held for the purchase of our common stock at the end of the purchase plan period.

        On the first day of a designated payroll deduction period, or offering period, we will grant to each eligible employee who has elected to participate in the purchase plan an option to purchase shares of our common stock as follows: the employee may authorize up to 15% of his or her base pay to be deducted by us during the offering period. On the last day of the offering period, the employee is deemed to have exercised the option, at the option exercise price, to the extent of accumulated payroll deductions. Under the terms of the 2004 employee stock purchase plan, the option exercise price is an amount equal to 85% of the lower of the closing price of our common stock on the first day or the last day of the offering period. For purposes of the first offering period under the purchase plan, the closing price of our common stock on the first day of such period is deemed to equal the initial public offering price per share in this offering.

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        In no event may an employee purchase in any one offering period a number of shares which exceeds the number of shares determined by dividing:

    the product of $2,083 and the number of full months in the offering period, by

    the closing price of a share of our common stock on the commencement date of the offering period.

        Our board of directors may, in its discretion, choose a different offering period for each subsequent offering.

        An employee who is not a participant on the last day of the offering period is not entitled to exercise any option, and the employee's accumulated payroll deductions will be refunded. An employee's rights under the 2004 employee stock purchase plan terminate upon voluntary withdrawal from the purchase plan at any time, or when the employee ceases employment for any reason, except that upon termination of employment because of death, the balance in the employee's account will be paid to the employee's beneficiary.

        Because participation in the purchase plan is voluntary, we cannot now determine the number of shares of our common stock to be purchased by any particular current executive officer, by all current executive officers as a group or by non-executive employees as a group.

401(k) Plan

        We maintain a retirement and deferred savings plan for our employees. The retirement and deferred savings plan is intended to qualify as a tax-qualified plan under Section 401 of the Code. The retirement and deferred savings plan provides that each participant may contribute up to 15% of his or her pre-tax compensation, up to a statutory limit, which for most employees is $13,000 in 2004. Under the plan, each employee is fully vested in his or her deferred salary contributions. Employee contributions are held and invested by the plan's trustee. The retirement and deferred savings plan also permits us to make discretionary contributions and matching contributions, subject to established limits and a vesting schedule. To date, we have not made any discretionary contributions to the retirement and deferred savings plan on behalf of participating employees.

Limitation of Liability and Indemnification of Officers and Directors

        Our certificate of incorporation that will be in effect upon completion of this offering limits the personal liability of directors for breach of fiduciary duty to the maximum extent permitted by the Delaware General Corporation Law. Our certificate of incorporation provides that no director will have personal liability to us or to our stockholders for monetary damages for breach of fiduciary duty or other duty as a director. However, these provisions do not eliminate or limit the liability of any of our directors:

    for any breach of their duty of loyalty to us or our stockholders;

    for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;

    for voting or assenting to unlawful payments of dividends or other distributions; or

    for any transaction from which the director derived an improper personal benefit.

        Any amendment to or repeal of these provisions will not eliminate or reduce the effect of these provisions in respect of any act or failure to act, or any cause of action, suit or claim that would accrue or arise prior to any amendment or repeal or adoption of an inconsistent provision. If the Delaware General Corporation Law is amended to provide for further limitations on the personal liability of

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directors of corporations, then the personal liability of our directors will be further limited to the greatest extent permitted by the Delaware General Corporation Law.

        In addition, our certificate of incorporation provides that we must indemnify our directors and officers and we must advance expenses, including attorneys' fees, to our directors and officers in connection with legal proceedings, subject to very limited exceptions.

        In addition to the indemnification provided for in our certificate of incorporation, we expect to enter into separate indemnification agreements with each of our directors and executive officers which may be broader than the specific indemnification provisions contained in the Delaware General Corporation Law. These indemnification agreements may require us, among other things, to indemnify our directors and executive officers for some expenses, including attorneys' fees, judgments, fines and settlement amounts incurred by a director or executive officer in any action or proceeding arising out of his service as one of our directors or executive officers, or any of our subsidiaries or any other company or enterprise to which the person provides services at our request. We believe that these provisions and agreements are necessary to attract and retain qualified individuals to serve as directors and executive officers. There is no pending litigation or proceeding involving any of our directors or executive officers to which indemnification is required or permitted, and we are not aware of any threatened litigation or proceeding that may result in a claim for indemnification.

Rule 10b5-1 Sales Plans

        Our directors and executive officers may adopt written plans, known as Rule 10b5-1 plans, in which they will contract with a broker to buy or sell shares of our common stock on a periodic basis. Under a Rule 10b5-1 plan, a broker executes trades pursuant to parameters established by the director or officer when entering into the plan, without further direction from them. The director or officer may amend or terminate the plan in some circumstances. Our directors and executive officers may also buy or sell additional shares outside of a Rule 10b5-1 plan when they are not in possession of material, nonpublic information.

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CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS

        Since our incorporation in May 2001, we have engaged in the following transactions with our directors and officers and holders of more than five percent of our voting securities and affiliates of our directors, officers and holders of more than five percent of our voting securities:

Stock Issuances

Issuances of Restricted Common Stock

        In June 2001, in connection with our formation, we issued an aggregate of 2,650,001 shares of restricted common stock at a price per share of $0.00008 to the following directors, officers and holders of more than five percent of our voting securities.

Name

  Number of Shares of
Common Stock

  Aggregate
Purchase Price

Robert S. Langer, Jr.   1,036,544   $ 80.98
Ram Sasisekharan   1,036,544     80.98
Ganesh Venkataraman   486,912     38.04
Alan L. Crane   30,000     2.34
Peter Barton Hutt   30,000     2.34
Lansing Brown Investments, LLC (John L. Zabriskie)   30,000     2.34

        In March 2002 and April 2002, we issued an aggregate of 1,071,068 shares of restricted common stock at a price per share of $0.11 and $0.13, respectively, to the following director and officer.

Name

  Number of Shares of
Common Stock

  Aggregate
Purchase Price

 
Alan L. Crane   980,858   $ 106,662.00 *
Susan K. Whoriskey   90,210     11,981.09  
*
Mr. Crane agreed to pay the purchase price in three installments on each of January 1, 2003, January 1, 2004 and January 1, 2005.

Issuance of Series A Convertible Preferred Stock and Warrants to Purchase Series A Prime Convertible Preferred Stock

        On August 16, 2001, we sold an aggregate of 250,000 shares of Series A convertible preferred stock at a price per share of $1.00 for an aggregate purchase price of $250,000, together with warrants to purchase an aggregate of 585,926 shares of our Series A prime convertible preferred stock with an exercise price per share of $1.7067. All shares of our Series A convertible preferred stock will be automatically converted into 319,999 shares of our common stock upon completion of this offering. Of the 250,000 shares of Series A convertible preferred stock originally issued, an aggregate of 230,000 shares, together with warrants to purchase 539,052 shares of our Series A prime convertible preferred stock, were sold to the following holders of more than five percent of our voting securities and its affiliates.

Name

  Number of Shares
of Series A
Convertible
Preferred Stock

  Number of Shares
of Series A Prime Convertible
Preferred Stock
Underlying
Warrants

  Aggregate
Purchase Price

Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   230,000   539,052   $ 230,000

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Issuance of Series A Prime Convertible Preferred Stock

        On January 24, 2002, we sold an aggregate of 893,537 shares of Series A prime convertible preferred stock, 539,052 of which were issued pursuant to the exercise of warrants issued to Polaris Venture Partners III, L.P. and related entities on August 16, 2001, at a price per share of $1.7067 for an aggregate purchase price of $1,524,999. All shares of our Series A prime convertible preferred stock will be automatically converted into 1,143,721 shares of our common stock upon completion of this offering. Of the 893,537 shares of Series A prime convertible preferred stock originally issued, an aggregate of 776,352 shares were sold to the following directors, officers and holders of more than five percent of our voting securities and their affiliates.

Name

  Number of Shares
of Series A
Prime Convertible
Preferred Stock

  Aggregate Purchase Price
Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   585,926   $ 999,999.90
Lansing Brown Investments, LLC (John L. Zabriskie)   58,593     100,000.67
Alan L. Crane   58,593     100,000.67
Peter Barton Hutt   29,296     49,999.48
Robert S. Langer, Jr.   29,296     49,999.48
Susan K. Whoriskey   14,648     24,999.74

Issuance of Series A Double Prime Convertible Preferred Stock

        On April 16, 2002, we sold an aggregate of 1,533,101 shares of Series A double prime convertible preferred stock at a price per share of $2.87 for an aggregate purchase price of $4,400,000. All shares of our Series A double prime convertible preferred stock will be automatically converted into 1,962,367 shares of our common stock upon completion of this offering. Of the 1,533,101 shares of Series A prime convertible preferred stock originally issued, an aggregate of 1,515,679 shares were sold to the following holders of more than five percent of our voting securities and their affiliates.

Name

  Number of Shares of Series A Double Prime Convertible Preferred Stock
  Aggregate Purchase Price
Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   1,132,404   $ 3,249,999.48
CHP II, L.P. (John K. Clarke)   348,432     999,999.84
Lansing Brown Investments, LLC (John L. Zabriskie)   34,843     99,999.41

Issuance of Series B Convertible Preferred Stock

        On May 9, 2003, we sold an aggregate of 6,440,678 shares of Series B convertible preferred stock at a price per share of $2.95 for an aggregate purchase price of $19,000,000. All shares of our Series B convertible preferred stock will be automatically converted into 8,244,062 shares of our common stock upon completion of this offering. All of the 6,440,678 shares of Series B convertible preferred stock

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originally issued were sold to the following holders of more than five percent of our voting securities and their affiliates.

Name

  Number of Shares of Series B Convertible Preferred Stock
  Aggregate Purchase Price
Atlas Venture entities (Peter Barrett)   2,415,254   $ 7,124,999.30
MVM International Life Sciences Fund No. 1 L.P. and related entities and individuals (Stephen T. Reeders)   1,779,661     5,249,999.95
Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   1,271,186     3,749,998.70
CHP II, L.P. (John K. Clarke)   974,577     2,875,002.15

Issuance of Series C Convertible Preferred Stock

        On February 27, 2004, we sold an aggregate of 2,612,696 shares of Series C convertible preferred stock at a price per share of $7.8463 for an aggregate purchase price of $20,499,996.62. All shares of our Series C convertible preferred stock will be automatically converted into 3,344,241 shares of our common stock upon completion of this offering. All of the 2,612,696 shares of Series C convertible preferred stock originally issued were sold to the following holders of more than five percent of our voting securities and their affiliates.

Name

  Number of Shares of Series C Convertible Preferred Stock
  Aggregate Purchase Price
Mithra Ventures, L.P.   881,788   $ 6,918,773.18
Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   613,247     4,811,719.94
Atlas Venture entities (Peter Barrett)   460,053     3,609,713.85
MVM International Life Sciences Fund No. 1 L.P. and related entities and individuals (Stephen T. Reeders)   338,986     2,659,785.85
CHP II, L.P. (John K. Clarke)   318,622     2,500,003.80

Certain Relationships

Consulting Agreement with Robert S. Langer, Jr.

        In July 2001, we entered into a consulting agreement with Robert S. Langer, Jr., one of our founders and a member of our board of directors, pursuant to which Dr. Langer provides consulting services as reasonably requested by us from time to time. The term of the consulting agreement was initially for two years, has been renewed for a one-year term and may be renewed for additional one-year terms by mutual agreement of us and Dr. Langer. Under the terms of the agreement, we provide compensation to Dr. Langer of up to $25,000, $50,000 or $100,000 on an annual basis contingent upon the achievement of certain milestones. We paid Dr. Langer $32,260 for consulting services in 2003. On or after the consummation by us of an initial public offering, we will pay Dr. Langer $100,000 as compensation for his services under the agreement.

Consulting Agreement with Ram Sasisekharan

        In August 2001, we entered into a consulting agreement with Ram Sasisekharan, one of our founders and a member of our board of directors, pursuant to which Dr. Sasisekharan provides consulting services as mutually determined by us and Dr. Sasisekharan from time to time. The term of the consulting agreement was initially for two years, has been renewed for a one-year term and may be renewed for additional one-year terms by mutual agreement of us and Dr. Sasisekharan. Under the terms of the agreement, we provide compensation to Dr. Sasisekharan of up to $25,000, $50,000 or

94



$100,000 on an annual basis contingent upon the achievement of certain milestones. We paid Dr. Sasisekharan $71,668 for consulting services in 2003. On or after the consummation by us of an initial public offering, we will pay Dr. Sasisekharan $100,000 as compensation for his services under the agreement.

Consulting Agreement with Peter Barton Hutt

        In September 2002, we entered into a consulting agreement with Peter Barton Hutt, a member of our board of directors, pursuant to which Mr. Hutt provides consulting and advisory services relating to the field of regulatory strategies for drug development. The consulting agreement provides for no more than an average of one day of service per month. The term of the consulting agreement was initially for one year, has been renewed for a one-year term and may be renewed for additional one-year terms by mutual agreement of us and Mr. Hutt. We granted Mr. Hutt a non-statutory stock option to purchase 6,400 shares of our common stock in 2002 at a purchase price of $0.23 per share valued at $8,600 and a non-statutory stock option to purchase 6,400 shares of our common stock in 2003 at a purchase price of $0.24 per share valued at $8,875. These options were granted in connection with this agreement.

Each of the above-mentioned consulting agreements were entered into on terms as favorable as could have been obtained by unrelated third parties.

Purchase of Restricted Stock by Alan L. Crane

        In connection with the execution of a restricted stock agreement effective March 15, 2002, Mr. Crane purchased 980,858 shares of restricted common stock for an aggregate purchase price of $106,662. Subject to certain vesting conditions, the 980,858 shares of restricted common stock issued to Mr. Crane are subject to a repurchase right by us at a per share price of $0.13. Mr. Crane agreed to pay the purchase price to us in three installments on each of January 1, 2003, January 1, 2004 and January 1, 2005.

Alan L. Crane Relationship with Polaris Venture Partners

        Mr. Crane has served as a venture partner of Polaris Venture Partners since 2002 and holds a carried interest in Polaris Venture Partners III and Polaris Venture Partners IV, each of which is an affiliate of a stockholder of Momenta. Until May 2003, Mr. Crane received compensation from Polaris Venture Partners, including $35,000 in 2003.

Reallocation of Founder Shares

        Pursuant to the terms of a Reallocation of Founder Shares Agreement dated April 10, 2002, each of Robert S. Langer, Jr. and Ram Sasisekharan transferred 51,200 shares of restricted common stock to Ganesh Venkataraman.

Ram Sasisekharan Relationship with Data Integration Provider

        Ram Sasisekharan, one of our co-founders and a member of our board of directors, is the brother of Sasisekharan Raguram, who is the chief technical officer of Parivid, LLC, a company that provides data integration services to us. As of March 31, 2004, we had not paid Parivid for data intergration services, but had accrued $26,000 for services rendered during the first quarter of 2004.

Director Compensation

        Please see "Management—Director Compensation" for a discussion of options granted to our non-employee directors.

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Executive Compensation and Employment Arrangements

        Please see "Management—Executive Compensation" and "Management—Option Grants in Last Fiscal Year" for additional information on compensation of our executive officers. Information regarding employment arrangements with several of our executive officers is set forth under "Management—Employment Arrangements."

Registration Rights

        Upon completion of this offering, the holders of 18,601,275 shares of our common stock, including a warrant exercisable to purchase 16,000 shares of common stock, are entitled to register their shares under the Securities Act. These rights are provided under the terms of an investors' rights agreement between us and these holders. These holders include the following directors, officers and holders of more than five percent of our voting securities and their affiliates:

Name of Holder

  Number of Registrable Shares
Alan L. Crane and affiliates   1,036,360
Ganesh Venkataraman   589,312
Susan K. Whoriskey   14,648
Peter Barton Hutt   29,296
Robert S. Langer, Jr. and affiliates   1,022,842
Ram Sasisekharan   985,344
Lansing Brown Investments, LLC (John L. Zabriskie)   119,598
Polaris Venture Partners III, L.P. and related entities (Christoph H. Westphal)   4,905,930
Atlas Venture entities (Peter Barrett)   3,680,387
MVM International Life Sciences Fund No. 1 L.P. and related entities and individuals (Stephen T. Reeders)   2,711,863
CHP II, L.P. (John K. Clarke)   2,101,286
Mithra Ventures, L.P.   1,128,688
   
  Total:   18,325,554
   

        The holders of these registration rights have waived their right to participate in this offering.

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PRINCIPAL STOCKHOLDERS

        The following table sets forth information with respect to the beneficial ownership of our common stock as of April 30, 2004, by:

        The column entitled "Percentage of Shares Beneficially Owned—Before Offering" is based on 19,213,183 shares of common stock outstanding as of April 30, 2004, assuming conversion of all outstanding shares of convertible preferred stock, but assuming no exercise of outstanding warrants or options. The column entitled "Percentage of Shares Beneficially Owned—After Offering" is based on 24,563,183 shares of common stock to be outstanding after this offering, including the 5,350,000 shares that we are selling in this offering, but not including any shares issuable upon exercise of warrants or options.

        For purposes of the table below, we deem shares subject to options or warrants that are currently exercisable or exercisable within 60 days of April 30, 2004 to be outstanding and to be beneficially owned by the person holding the options for the purpose of computing the percentage ownership of that person but we do not treat them as outstanding for the purpose of computing the percentage ownership of any other person. Except as otherwise noted, the persons or entities in this table have sole voting and investing power with respect to all of the shares of common stock beneficially owned by them, subject to community property laws, where applicable. Except as otherwise set forth below, the street address of the beneficial owner is c/o Momenta Pharmaceuticals, Inc., 43 Moulton Street, Cambridge, Massachusetts 02138.

 
   
  Percentage of Shares Beneficially Owned
 
Name and Address of Beneficial Owner

  Number of Shares
Beneficially Owned

  Before Offering
  After Offering
 
Holders of more than 5% of our voting securities              
Polaris Venture Partners III, L.P. and related entities
Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02457
  4,905,930 (1) 25.5 % 20.0 %
Atlas Venture entities
890 Winter Street, Suite 320
Waltham, MA 02451
  3,680,387 (2) 19.2 % 15.0 %
MVM International Life Sciences Fund No. 1 L.P. and related entities and individuals
6 Henrietta Street
London WC2E 8PU
 
2,711,863

(3)

14.1

%

11.0

%
CHP II, L.P.
c/o Cardinal Partners
221 Nassau Street
Princeton, NJ 08542
  2,101,286 (4) 10.9 % 8.6 %
Mithra Ventures, L.P.
205 Newbury Street, 3 rd Floor
Boston, MA 02116
  1,128,688 (5) 5.9 % 4.6 %
Alan L. Crane   1,077,677 (6) 5.6 % 4.4 %
Ram Sasisekharan   985,344 (7) 5.1 % 4.0 %
Robert S. Langer, Jr.   976,762 (8) 5.1 % 4.0 %

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  Percentage of Shares Beneficially Owned
 
Name and Address of Beneficial Owner

  Number of Shares
Beneficially Owned

  Before Offering
  After Offering
 
Directors and named executive officers              
Peter Barrett   3,680,387 (2) 19.2 % 15.0 %
John K. Clarke   2,101,286 (4) 10.9 % 8.6 %
Peter Barton Hutt   91,498 (9) *   *  
Robert S. Langer, Jr.   976,762 (8) 5.1 % 4.0 %
Stephen T. Reeders   2,711,863 (3) 14.1 % 11.0 %
Ram Sasisekharan   985,344 (7) 5.1 % 4.0 %
Bennett M. Shapiro   20,299 (10) *   *  
Christoph H. Westphal   4,905,930 (1) 25.5 % 20.0 %
John L. Zabriskie   162,398 (11) *   *  
Alan L. Crane   1,077,677 (6) 5.6 % 4.4 %
Steven B. Brugger   50,880 (12) *   *  
Ganesh Venkataraman   599,712 (13) 3.1 % 2.4 %
Susan K. Whoriskey   120,713 (14) *   *  
Joseph E. Tyler   41,600 (15) *   *  
All directors and executive officers as a group (15 persons)   17,526,349 (16) 90.4 % 70.8 %

*
Represents beneficial ownership of less than one percent of common stock.

(1)
Consists of (a) 4,709,425 shares of common stock held by Polaris Venture Partners III, L.P. issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 122,278 shares of common stock held by Polaris Venture Partners Entrepreneurs' Fund III, L.P. issuable upon the automatic conversion of preferred stock upon the completion of this offering and (c) 74,227 shares of common stock held by Polaris Venture Partners Founders' Fund III, L.P. issuable upon the automatic conversion of preferred stock upon the completion of this offering. Polaris Venture Management Co. III, L.L.C. is the general partner of Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P. and Polaris Venture Partners Founders' Fund III, L.P. The managing members of Polaris Venture Management Co. III, L.L.C. are Stephen D. Arnold, Jonathan A. Flint, Terrance G. McGuire and Alan G. Spoon, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares. Christoph H. Westphal, a director of Momenta, is a non-managing member of Polaris Venture Management Co. III, L.L.C. Dr. Westphal disclaims beneficial ownership of these shares except to the extent of his proportionate pecuniary interest in such shares.

(2)
Consists of (a) 1,163,688 shares of common stock held by Atlas Venture Fund V, L.P. issuable upon the automatic conversion of preferred stock upon completion of this offering, (b) 144,548 shares of common stock held by Atlas Venture Parallel Fund V-A, C.V. issuable upon the automatic conversion of preferred stock upon completion of this offering, (c) 144,548 shares of common stock held by Atlas Venture Parallel Fund V-B, C.V. issuable upon the automatic conversion of preferred stock upon completion of this offering, (d) 19,368 shares of common stock held by Atlas Venture Entrepreneurs' Fund V, L.P. issuable upon the automatic conversion of preferred stock upon completion of this offering, (e) 2,105,305 shares of common stock held by Atlas Venture Fund VI, L.P. issuable upon the automatic conversion of preferred stock upon completion of this offering, (f) 64,381 shares of common stock held by Atlas Venture Entrepreneurs' Fund VI, L.P. issuable upon the automatic conversion of preferred stock upon completion of this offering and (g) 38,549 shares of common stock held by Atlas Venture Fund VI GmbH & Co. KG issuable upon the automatic conversion of preferred stock upon completion of this offering. Atlas Venture Associates V, L.P. is the general partner of Atlas Venture Fund V, L.P., Atlas Venture Parallel Fund V-A, C.V., Atlas Venture Parallel Fund V-B, C.V. and Atlas Venture Entrepreneurs' Fund V, L.P. Atlas Venture Associates VI, L.P. is the general partner of Atlas Venture Fund VI, L.P. and Atlas Venture Entrepreneurs' Fund VI, L.P. and the managing limited

98


(3)
Consists of (a) 2,684,748 shares of common stock held by MVM International Life Sciences Fund No. 1 L.P. issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 8,656 shares of common stock held by MVM Limited issuable upon the automatic conversion of preferred stock upon the completion of this offering, (c) 5,965 shares of common stock held by Stephen T. Reeders issuable upon the automatic conversion of preferred stock upon completion of this offering, (d) 5,965 shares of common stock held by David Brister issuable upon the automatic conversion of preferred stock upon completion of this offering, (e) 5,965 shares of common stock held by Paul Triniman issuable upon the automatic conversion of preferred stock upon the completion of this offering, (f) 96 shares of common stock held by Martin Murphy issuable upon the automatic conversion of preferred stock upon completion of this offering, (g) 234 shares of common stock held by Richard Lim issuable upon the automatic conversion of preferred stock upon completion of this offering and (h) 234 shares of common stock held by Thomas Casdagli issuable upon the automatic conversion of preferred stock upon completion of this offering. Stephen Reeders, Paul Triniman and David Brister are the investment directors of MVM Limited, which individuals exercise discretionary investment power over securities held by MVM International Life Sciences Fund No. 1 L.P., MVM Limited, Stephen Reeders, Paul Triniman, David Brister, Martin Murphy, Richard Lim and Thomas Casdagli, and are principally responsible for the selection, acquisition and disposition of these securities. Dr. Reeders, a director of Momenta, disclaims beneficial ownership of these shares except to the extent of his proportionate pecuniary interest in such shares.

(4)
Consists of 2,101,286 shares of common stock held by CHP II, L.P. issuable upon the automatic conversion of preferred stock upon completion of this offering. John K. Clarke, a director of Momenta, Brandon H. Hull, Lisa Skeete Tatum and John J. Park are the managing members of CHP II Management, LLC, the General Partner of CHP II, L.P., and exercise shared voting, investment, and dispositive rights with respect to the shares of stock held by CHP II, L.P. Each of Messrs. Clarke, Hull and Park and Ms. Skeete Tatum disclaims beneficial ownership of the shares identified in this footnote except as to his or her respective proportionate pecuniary interest in such shares.

(5)
Consists of 1,128,688 shares of common stock issuable upon the automatic conversion of preferred stock upon the completion of this offering. Farah Ebrahimi and Nina Ross, the managing members of the general partner of Mithra Ventures, L.P., exercise shared voting and investment power with respect to the shares owned by Mitra Ventures, L.P. Each of Ms. Ebrahimi and Ms. Ross disclaim beneficial ownership of such shares except to the extent of her respective pecuniary interest therein.

(6)
Consists of (a) 25,501 shares of common stock issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 1,010,859 shares of restricted common stock, of which 436,627 shares remain subject to a repurchase right by us pursuant to restricted stock agreements between us and Mr. Crane and (c) 41,317 shares of common stock underlying options exercisable within 60 days of April 30, 2004.

(7)
Consists of 985,344 shares of restricted common stock, of which 246,336 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Dr. Sasisekharan.

99


(8)
Consists of (a) 37,498 shares of common stock issuable upon the automatic conversion of preferred stock upon the completion of this offering and (b) 939,264 shares of restricted common stock, of which 246,336 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Dr. Langer.

(9)
Consists of (a) 37,498 shares of common stock issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 30,000 shares of restricted common stock, of which 7,500 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Mr. Hutt and (c) 24,000 shares of common stock underlying options exercisable within 60 days of April 30, 2004.

(10)
Consists of 15,859 shares of common stock underlying options exercisable within 60 days of April 30, 2004.

(11)
Consists of (a) 93,436 shares of common stock held by Lansing Brown Investments, LLC issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 23,438 shares of restricted common stock held by Lansing Brown Investments, LLC, of which 5,860 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Lansing Brown Investments, LLC and (c) 10,000 shares of common stock underlying options held by John L. Zabriskie exercisable within 60 days of April 30, 2004. Dr. Zabriskie, a director of Momenta, is the president of Lansing Brown Investments, LLC and disclaims beneficial ownership of shares held by Lansing Brown Investment, LLC except to the extent of his proportionate pecuniary interest in such shares.

(12)
Consists of 20,299 shares of common stock underlying options exercisable within 60 days of April 30, 2004.

(13)
Consists of (a) 589,312 shares of restricted common stock, of which 147,328 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Dr. Venkataraman and (b) 10,400 shares of common stock underlying options exercisable within 60 days of April 30, 2004.

(14)
Consists of (a) 18,749 shares of common stock issuable upon the automatic conversion of preferred stock upon the completion of this offering, (b) 3,754 shares of common stock, (c) 90,210 shares of restricted common stock, of which 37,491 shares remain subject to a repurchase right by us pursuant to a restricted stock agreement between us and Dr. Whoriskey and (c) 8,000 shares of common stock underlying options exercisable with 60 days of April 30, 2004.

(15)
Consists of (a) 28,000 shares of common stock and (b) 13,600 shares of common stock exercisable within 60 days of April 30, 2004.

(16)
See footnotes 1-4 and 6-15 above.

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DESCRIPTION OF CAPITAL STOCK

        The following description of our capital stock and provisions of our certificate of incorporation and by-laws are summaries and are qualified by reference to the certificate of incorporation and the by-laws that will be in effect upon the completion of this offering. Copies of these documents have been filed with the Securities and Exchange Commission as exhibits to our registration statement, of which this prospectus forms a part. The descriptions of the common stock and preferred stock reflect changes to our capital structure that will occur upon the completion of this offering.

        Upon the completion of this offering, our authorized capital stock will consist of 100,000,000 shares of common stock, par value $0.0001 per share, and 5,000,000 shares of preferred stock, par value $0.01 per share, all of which preferred stock will remain undesignated.

        As of April 30, 2004, we had issued and outstanding:

        As of April 30, 2004, we also had outstanding a warrant to purchase 12,500 shares of Series A double prime convertible preferred stock at an exercise price of $2.87.

        Upon the completion of this offering, all of the outstanding shares of our preferred stock will automatically convert into a total of 15,014,390 shares of our common stock. In addition, upon completion of this offering, a warrant to purchase an aggregate of 12,500 shares of Series A double prime convertible preferred stock will remain outstanding and will be exercisable for 16,000 shares of common stock at an exercise price of $2.2422 per common share. If this warrant is exercised for cash, we would issue an aggregate of 16,000 shares of common stock for cash proceeds of approximately $35,875.

Common Stock

        Holders of common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Accordingly, holders of a majority of the shares of common stock entitled to vote in any election of directors may elect all of the directors standing for election. Holders of common stock are entitled to receive proportionately any dividends as may be declared by our board of directors, subject to any preferential dividend rights of outstanding preferred stock.

        In the event of our liquidation, dissolution or winding up, the holders of common stock are entitled to receive proportionately our net assets available after the payment of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock. Holders of common stock have no preemptive, subscription, redemption or conversion rights. Our outstanding shares of common stock are and the shares offered by us in this offering will be, when issued and paid for, validly issued, fully paid and nonassessable. The rights, preferences and privileges of holders of common stock are subject to and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

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Preferred Stock

        Under the terms of our certificate of incorporation, our board of directors is authorized to direct us to issue shares of preferred stock in one or more series without stockholder approval. Our board of directors has the discretion to determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences of each series of preferred stock.

        The purpose of authorizing our board of directors to issue preferred stock and determine its rights and preferences is to eliminate delays associated with a stockholder vote on specific issuances. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions, future financings and other corporate purposes, could have the effect of making it more difficult for a third party to acquire, or could discourage a third party from seeking to acquire, a majority of our outstanding voting stock. Upon completion of this offering, there will be no shares of preferred stock outstanding and we have no present plans to issue any shares of preferred stock.

Warrants

        Upon completion of this offering, we will have an outstanding warrant to purchase 16,000 shares of our common stock at an exercise price of $2.2422 per common share. The warrant expires on December 27, 2012 and provides for assumption and/or adjustments in the event of specified mergers, reorganizations, reclassifications, stock dividends, stock splits or other changes in our corporate structure.

Options

        As of April 30, 2004, options to purchase 1,148,900 shares of common stock at a weighted average exercise price of $0.64 per share were outstanding.

Antitakeover Provisions

        We are subject to Section 203 of the Delaware General Corporation Law. Subject to certain exceptions, Section 203 prevents a publicly-held Delaware corporation from engaging in a "business combination" with any "interested stockholder" for three years following the date that the person became an interested stockholder, unless the interested stockholder attained such status with the approval of our board of directors or unless the business combination is approved in a prescribed manner. A "business combination" includes, among other things, a merger or consolidation involving us, and the interested stockholder and the sale of more than 10% of our assets. In general, an "interested stockholder" is any entity or person beneficially owning 15% or more of our outstanding voting stock and any entity or person affiliated with or controlling or controlled by such entity or person.

        Our certificate of incorporation and our by-laws divide our board of directors into three classes with staggered three-year terms. In addition, our certificate of incorporation and our by-laws provide that directors may be removed only for cause and only by the affirmative vote of the holders of 75% or more of our shares of capital stock present in person or by proxy and entitled to vote. Under our certificate of incorporation and by-laws, any vacancy on our board of directors, including a vacancy resulting from an enlargement of our board of directors, may be filled only by vote of a majority of our directors then in office. The classification of our board of directors and the limitations on the ability of our stockholders to remove directors and fill vacancies could make it more difficult for a third party to acquire, or discourage a third party from seeking to acquire, control of our company.

        Our certificate of incorporation and our by-laws provide that any action required or permitted to be taken by our stockholders at an annual meeting or special meeting of stockholders may only be

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taken if it is properly brought before such meeting and may not be taken by written action in lieu of a meeting. Our certificate of incorporation and our by-laws also provide that, except as otherwise required by law, special meetings of the stockholders can only be called by our chairman of the board, our chief executive officer or our board of directors. In addition, our by-laws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of stockholders, including proposed nominations of candidates for election to our board of directors. Stockholders at an annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of our board of directors or by a stockholder of record on the record date for the meeting, who is entitled to vote at the meeting and who has delivered timely written notice in proper form to our secretary of the stockholder's intention to bring such business before the meeting. These provisions could have the effect of delaying stockholder actions that are favored by the holders of a majority of our outstanding voting securities until the next stockholder meeting.

        The Delaware General Corporation Law provides generally that the affirmative vote of a majority of the shares entitled to vote on any matter is required to amend a corporation's certificate of incorporation or by-laws, unless a corporation's certificate of incorporation or by-laws, as the case may be, requires a greater percentage. Our by-laws may be amended or repealed by a majority vote of our board of directors or by the affirmative vote of the holders of at least 75% of the votes which all our stockholders would be entitled to cast in any annual election of directors. In addition, the affirmative vote of the holders of at least 75% of the votes which all our stockholders would be entitled to cast in any election of directors is required to amend or repeal or to adopt any provisions inconsistent with any of the provisions of our certificate of incorporation described in the prior two paragraphs.

Registration Rights

        Upon the completion of this offering, holders of an aggregate of approximately 18,601,275 shares of our common stock, including a warrant exercisable to purchase 16,000 shares of common stock, will have the right to require us to register these shares under the Securities Act under specific circumstances.

        Demand registration rights.     At any time after the earlier of May 9, 2006 and six months after this offering, subject to specified limitations, these stockholders may require that we register on not more than two occasions all or part of these securities for sale under the Securities Act. Once we are qualified to use Form S-3, holders of these shares may make demands for registrations on Form S-3 on up to two occasions during any 12-month period.

        Incidental registration rights.     If we register any of our common stock, either for our own account or for the account of other security holders, subject to certain exceptions, these stockholders are entitled to notice of the registration and to include their shares of common stock in the registration.

        Limitations and expenses.     With specified exceptions, a holder's right to include shares in a registration is subject to the right of the underwriters to limit the number of shares included in the offering. We will pay all fees, costs and expenses of any demand or incidental registrations, and the holders of the securities being registered will pay all selling expenses.

Transfer Agent and Registrar

        The transfer agent and registrar for our common stock is American Stock Transfer & Trust Co.

NASDAQ National Market

        We have applied to have our common stock approved for quotation on the NASDAQ National Market under the symbol "MNTA."

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SHARES ELIGIBLE FOR FUTURE SALE

        Prior to this offering, there has been no market for our common stock, and we cannot assure you that a liquid trading market for our common stock will develop or be sustained after this offering. Future sales of substantial amounts of common stock, including shares issued upon exercise of options and warrants, in the public market after this offering, or the anticipation of those sales, could adversely affect market prices prevailing from time to time and could impair our ability to raise capital through sales of our equity securities.

        Upon completion of this offering, we will have outstanding 24,563,183 shares of common stock, after giving effect to the automatic conversion of all outstanding shares of our convertible preferred stock into an aggregate of 15,014,390 shares of common stock.

        Of the shares to be outstanding after completion of this offering, the 5,350,000 shares sold in this offering will be freely tradable without restriction under the Securities Act unless purchased by our "affiliates," as that term is defined in Rule 144 under the Securities Act. The remaining shares are "restricted securities" under Rule 144. Substantially all of these restricted securities will be subject to the 180-day lock-up period described below.

        After the 180-day lock-up period, these restricted securities may be sold in the public market only if registered or if they qualify for an exemption from registration under Rule 144 or 701 under the Securities Act, which rules are summarized below.

Rule 144

        In general, under Rule 144, beginning 90 days after the date of this prospectus, a person who has beneficially owned shares of our common stock for at least one year would be entitled to sell within any three-month period a number of shares that does not exceed the greater of:

        Sales under Rule 144 are also subject to manner of sale provisions and notice requirements and to the availability of current public information about us. Upon completion of the 180-day lock-up period, substantially all of our outstanding restricted securities will be eligible for sale under Rule 144.

Rule 144(k)

        Subject to the lock-up agreements described below, shares of our common stock eligible for sale under Rule 144(k) may be sold immediately upon the completion of this offering. In general, under Rule 144(k), a person may sell shares of common stock acquired from us immediately upon completion of this offering, without regard to manner of sale, the availability of public information or volume, if:

        Upon expiration of the 180-day lock-up period, unless held by our affiliates, 3,426,087 shares of common stock underlying our Series A convertible preferred stock, Series A prime convertible preferred stock and Series A double prime convertible preferred stock will be eligible for sale under Rule 144(k). In addition, unless held by our affiliates, 8,244,062 shares of common stock underlying our

104



Series B convertible preferred stock will be eligible for sale under Rule 144(k) in May 2005. In addition, unless held by our affiliates, 3,344,241 shares of common stock underlying our Series C convertible preferred stock will be eligible for sale under Rule 144(k) in February 2006. Furthermore, unless held by our affiliates, the shares issued upon cashless exercise of the warrant to purchase Series A double prime convertible preferred stock will be eligible for sale under Rule 144(k) in December 2004.

Rule 701

        In general, under Rule 701 of the Securities Act, any of our employees, consultants or advisors who purchased shares from us in connection with a qualified compensatory stock plan or other written agreement are eligible to resell those shares 90 days after the effective date of this offering in reliance on Rule 144, but without compliance with various restrictions, including the holding period, contained in Rule 144. Subject to the 180-day lock-up period, approximately 1,148,900 shares of common stock will be eligible for sale in accordance with Rule 701.

Lock-Up Agreements

        The holders of substantially all of our currently outstanding stock have agreed that, subject to the exceptions described in the "Underwriters" section, without the prior written consent of SG Cowen & Co., LLC and Banc of America Securities LLC on behalf of the underwriters, they will not, during the period ending 180 days after the date of this prospectus sell, offer, contract or grant any option to sell (including, without limitation any short sale), pledge, transfer, establish an open "put equivalent position" or otherwise dispose of any shares of our common stock, options or warrants to acquire shares of our common stock or securities exchangeable or exercisable for or convertible into shares of our common stock.

        Furthermore, stockholders who purchased shares from us upon exercise of stock options have agreed with us that they will not sell any of their shares for a period of 180 days after the date of this prospectus.

Registration Rights

        Upon the completion of this offering, the holders of an aggregate of 18,601,275 shares of our common stock, including shares issuable upon exercise of our outstanding warrant, will have the right to require us to register these shares under the Securities Act under certain circumstances. After registration pursuant to these rights, these shares will become freely tradable without restriction under the Securities Act. For more information regarding these registration rights, see "Description of Capital Stock—Registration Rights."

Stock Options

        As of April 30, 2004, we had outstanding options to purchase 1,148,900 shares of common stock. Following this offering, we intend to file registration statements on Form S-8 under the Securities Act to register all of the shares of common stock subject to outstanding stock options together with options and other awards issuable pursuant to our 2002 stock incentive plan, 2004 stock incentive plan and 2004 employee stock purchase plan.

Warrants

        Upon completion of this offering, there will be a warrant outstanding to purchase 16,000 shares of our common stock at an exercise price of $2.2422 per common share. Any shares purchased pursuant to the "cashless exercise" feature of this warrant will be freely tradeable under Rule 144(k).

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UNDERWRITING

General

        Under the underwriting agreement, which is filed as an exhibit to the registration statement relating to this prospectus, each of the underwriters named below has severally agreed to purchase from us the number of shares of common stock shown opposite its name below:

Underwriters

  Number of Shares
SG Cowen & Co., LLC    
Banc of America Securities LLC    
CIBC World Markets Corp.    
ThinkEquity Partners LLC    
   
  Total   5,350,000
   

        The underwriting agreement provides that the underwriters' obligations to purchase shares of common stock depend on the satisfaction of the conditions contained in the underwriting agreement, including:

    the obligation to purchase all of the shares of common stock offered hereby if any of the shares are purchased;

    the representations and warranties made by us to the underwriters are true;

    there is no material change in the financial markets; and

    we deliver customary closing documents to the underwriters.

        SG Cowen & Co., LLC and Banc of America Securities LLC are acting as Joint Book-Running Managers on behalf of the underwriting syndicate. As Joint Book-Running Managers, they will be responsible for recording a list of potential investors that have expressed an interest in purchasing shares of common stock as part of this offering.

        The underwriters have informed us that they do not expect to make sales to accounts over which they exercise discretionary authority to exceed five percent of the total number of shares of common stock offered by them.

Over-Allotment Option

        We have granted to the underwriters an option to purchase up to an aggregate of 802,500 additional shares of common stock, exercisable to cover over-allotments at the public offering price less the underwriting discount shown on the cover page of this prospectus. The underwriters may exercise this option at any time, and from time to time, until 30 days after the date of the underwriting agreement. To the extent the underwriters exercise this option, each underwriter will be committed, so long as the conditions of the underwriting agreement are satisfied, to purchase a number of additional shares of common stock proportionate to that underwriter's initial commitment as indicated in the preceding table, and we will be obligated to sell the additional shares of common stock to the underwriters.

Commissions and Expenses

        The following table summarizes the underwriting discount that we will pay. These amounts are shown assuming both no exercise and full exercise of the underwriters' option to purchase up to an

106



additional 802,500 shares from us. The underwriting fee is the difference between the public offering price and the amount the underwriters pay to purchase the shares from us.

 
  Paid by Momenta
 
  No Exercise
  Full Exercise
Per Share   $     $  
Total   $     $  

        The underwriters have advised us that they propose to offer the shares of common stock directly to the public at the public offering price presented on the cover page of this prospectus, and to selected dealers, who may include the underwriters, at the public offering price less a selling concession not in excess of $                      per share. The underwriters may allow, and the selected dealers may reallow, a concession not in excess of $                      per share to brokers and dealers. After the offering, the underwriters may change the offering price and other selling terms.

        We estimate that our total expenses of this offering, including registration, filing and listing fees, printing fees and legal and accounting expenses, but excluding underwriting discounts, will be approximately $1.4 million.

Lock-up Agreements

        We, our officers and directors and stockholders owning an aggregate of approximately 19,182,063 shares of common stock have entered into lock-up agreements with the underwriters. Under these agreements, we and each of these persons may not, without the prior written approval of SG Cowen & Co., LLC and Banc of America Securities LLC, offer, sell, contract to sell or otherwise dispose of or hedge our common stock or securities convertible into or exchangeable for our common stock. These restrictions will be in effect for a period of 180 days after the date of this prospectus. At any time and without notice, SG Cowen & Co., LLC and Banc of America Securities LLC may, in their sole discretion, release all or some of the securities from these lock-up agreements.

Quotation on the NASDAQ National Market

        We have applied for the quotation of our common stock on the NASDAQ National Market under the symbol "MNTA."

Indemnification

        We have agreed to indemnify the underwriters against liabilities relating to the offering, including liabilities under the Securities Act and liabilities arising from breaches of the representations and warranties contained in the underwriting agreement, and to contribute to payments that the underwriters may be required to make for these liabilities.

Stabilization, Short Positions and Penalty Bids

        The underwriters may engage in over-allotment, stabilizing transactions, syndicate covering transactions, and penalty bids or purchases for the purpose of pegging, fixing or maintaining the price of our common stock, in accordance with Regulation M under the Securities Exchange Act:

    Over-allotment involves sales by the underwriters of shares in excess of the number of shares the underwriters are obligated to purchase, which creates a syndicate short position. The short position may be either a covered short position or a naked short position. In a covered short position, the number of shares over-allotted by the underwriters is not greater than the number of shares that they may purchase in the over-allotment option. In a naked short position, the number of shares involved is greater than the number of shares in the over-allotment option.

107


      The underwriters may close out any short position by exercising their over-allotment option and/or purchasing shares in the open market.

    Stabilizing transactions permit bids to purchase common stock so long as the stabilizing bids do not exceed a specified maximum.

    Syndicate covering transactions involve purchases of common stock in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares to close out the short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which they may purchase shares through the over-allotment option. If the underwriters sell more shares than could be covered by the over-allotment option, a naked short position, the position can only be closed out by buying shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that there could be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase in the offering.

    Penalty bids permit the underwriters to reclaim a selling concession from a syndicate member when the common stock originally sold by the syndicate member is purchased in a stabilizing or syndicate covering transaction to cover syndicate short positions.

        These stabilizing transactions, syndicate covering transactions and penalty bids may raise or maintain the market price of our common stock or prevent or slow a decline in the market price of our common stock. As a result, the price of our common stock may be higher than the price that might otherwise exist in the open market. These transactions may be effected on the NASDAQ National Market or otherwise and, if commenced, may be discontinued at any time.

        Neither we nor any of the underwriters make any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of our common stock. In addition, neither we nor the underwriters make any representation that the underwriters will engage in these stabilizing transactions or that any transaction, once commenced, will not be discontinued without notice.

Passive Market Making

        In connection with this offering, underwriters and selling group members may engage in passive market making transactions in our common stock on the NASDAQ National Market in accordance with Rule 103 of Regulation M under the Securities Exchange Act during the period before the commencement of offers or sales of common stock and extending through the completion of the distribution. A passive market maker must display its bids at a price not in excess of the highest independent bid of the security. However, if all independent bids are lowered below the passive market maker's bid, that bid must be lowered when specified purchase limits are exceeded.


Prospectus Delivery

        Neither the underwriters nor any of their affiliates intend to use any means of distributing a prospectus other than by delivering a paper-based copy of such prospectus by hand or postal mail.

Directed Share Program

        At our request, the underwriters have reserved for sale, at the initial public offering price, up to 214,000 shares offered in this prospectus for directors, officers, employees, business associates and other persons with whom we have a relationship. The number of shares of common stock available for sale to the general public will be reduced to the extent these persons purchase reserved shares. Any

108



reserved shares which are not purchased will be offered by the underwriters to the general public on the same basis as the other shares offered by this prospectus.

Pricing of the Offering

        Prior to this offering, there has been no public market for our common stock. The initial public offering price will be determined by negotiations between us and the representatives. Among the factors to be considered in determining the initial public offering price will be our future prospects and those of our industry in general, our revenues, earnings and other financial operating information in recent periods, and the price-earnings ratios, price-sales ratios, market prices of securities and financial and operating information of companies engaged in activities similar to ours. The estimated initial public offering price range set forth on the cover page of this preliminary prospectus is subject to change as a result of market conditions and other factors.

Conflicts/Affiliates

        The underwriters and their affiliates may from time to time engage in future transactions with us and our affiliates and provide services to us and our affiliates in the ordinary course of their business for which services they may in the future receive customary fees.

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LEGAL MATTERS

        Certain legal matters with respect to the validity of the shares of common stock offered hereby will be passed upon for us by Wilmer Cutler Pickering Hale and Dorr LLP, Boston, Massachusetts. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. has acted as counsel for the underwriters in connection with certain legal matters related to this offering.


EXPERTS

        Ernst & Young LLP, independent auditors, have audited our financial statements at December 31, 2002 and 2003, and the period from May 17, 2001 (date of our inception) to December 31, 2001 and the years ended December 31, 2002 and 2003, as set forth in their report. We have included our financial statements in the prospectus in reliance on Ernst & Young LLP's report, given on their authority as experts in accounting and auditing.


WHERE YOU CAN FIND MORE INFORMATION

        We have filed with the Securities and Exchange Commission a registration statement on Form S-1 under the Securities Act with respect to the shares of common stock we are offering to sell. This prospectus, which constitutes part of the registration statement, does not include all of the information contained in the registration statement. You should refer to the registration statement and its exhibits for additional information. Whenever we make reference in this prospectus to any of our contracts, agreements or other documents, the references are not necessarily complete and you should refer to the exhibits attached to the registration statement for copies of the actual contract, agreement or other document. When we complete this offering, we will also be required to file annual, quarterly and special reports, proxy statements and other information with the Securities and Exchange Commission. We anticipate making these documents publicly available, free of charge, on our website at www.momentapharma.com as soon as reasonably practicable after filing such documents with the Securities and Exchange Commission.

        You can read the registration statement and our future filings with the Securities and Exchange Commission, over the Internet at the Securities and Exchange Commission's web site at http://www.sec.gov . You may also read and copy any document that we file with the Securities and Exchange Commission at its public reference room at 450 Fifth Street, N.W., Washington, DC 20549.

        You may also obtain copies of the documents at prescribed rates by writing to the Public Reference Section of the Securities and Exchange Commission at 450 Fifth Street, NW, Washington, DC 20549. Please call the Securities and Exchange Commission at 1-800-SEC-0330 for further information on the operation of the public reference room.

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MOMENTA PHARMACEUTICALS, INC.

INDEX TO FINANCIAL STATEMENTS

 
  Page
Report of Independent Registered Public Accounting Firm   F-2

Balance Sheets as of December 31, 2002 and 2003 and March 31, 2004 (unaudited)

 

F-3

Statements of Operations for the Period from May 17, 2001 (Date of Inception) to December 31, 2001 and Years Ended December 31, 2002 and 2003 and the three months ended March 31, 2003 and 2004 (unaudited)

 

F-4

Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) for the Period from May 17, 2001 (Date of Inception) to December 31, 2001 and Years Ended December 31, 2002 and 2003 and the three months ended March 31, 2004 (unaudited)

 

F-5

Statements of Cash Flows for the Period from May 17, 2001 (Date of Inception) to December 31, 2001 and Years Ended December 31, 2002 and 2003 and the three months ended March 31, 2003 and 2004 (unaudited)

 

F-9

Notes to Financial Statements

 

F-10

F-1



REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors and Stockholders
Momenta Pharmaceuticals, Inc.

        We have audited the accompanying balance sheets of Momenta Pharmaceuticals, Inc. as of December 31, 2002 and 2003, and the related statements of operations, redeemable convertible preferred stock and stockholders' deficit, and cash flows for the period from May 17, 2001 (date of inception) to December 31, 2001 and the years ended December 31, 2002 and 2003. These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on these financial statements based on our audits.

        We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

        In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of Momenta Pharmaceuticals, Inc. at December 31, 2002 and 2003, and the results of its operations and its cash flows for the period from May 17, 2001 (date of inception) to December 31, 2001 and the years ended December 31, 2002 and 2003, in conformity with U.S. generally accepted accounting principles.

  /s/ ERNST & YOUNG LLP

Boston, Massachusetts
February 27, 2004, except for the first four
paragraphs of Note 16, as to
which the date is March 8, 2004

F-2



MOMENTA PHARMACEUTICALS, INC.

BALANCE SHEETS

 
  December 31,
   
 
 
  2002
  2003
  March 31, 2004
 
 
   
   
  (Unaudited)

 
Assets                    
Current assets:                    
  Cash and cash equivalents   $ 1,470,554   $ 4,612,674   $ 16,585,476  
  Short-term investments         7,994,250     14,614,503  
  Unbilled collaboration revenue         2,018,380     999,743  
  Prepaid expenses and other current assets     53,136     261,551     1,161,474  
   
 
 
 
    Total current assets     1,523,690     14,886,855     33,361,196  

Property and equipment, net of accumulated depreciation

 

 

867,829

 

 

1,117,206

 

 

1,055,083

 
Other assets     108,586     79,520     99,986  
   
 
 
 
    Total assets   $ 2,500,105   $ 16,083,581   $ 34,516,265  
   
 
 
 

Liabilities, Redeemable Convertible Preferred Stock and Stockholders' Deficit

 

 

 

 

 

 

 

 

 

 

Current liabilities:

 

 

 

 

 

 

 

 

 

 
  Accounts payable   $ 287,515   $ 804,137   $ 597,807  
  Accrued expenses     603,639     570,867     1,068,026  
  Deferred revenue         147,155     147,155  
  Line of credit obligation         320,868     325,019  
   
 
 
 
    Total current liabilities     891,154     1,843,027     2,138,007  
  Deferred revenue—net of current portion         416,938     380,149  
  Line of credit obligation—net of current portion         371,614     288,788  
  Unvested restricted stock     12,888     6,476     5,242  
   
 
 
 
    Total liabilities     904,042     2,638,055     2,812,186  

Commitments and contingencies

 

 

 

 

 

 

 

 

 

 
Redeemable convertible preferred stock, $0.01 par value, issuable in series; 10,000,000 shares authorized at December 31, 2002 and 2003 and 12,000,000 authorized at March 31, 2004; 2,676,638, 9,117,316 and 11,730,012 shares issued and outstanding at December 31, 2002, 2003 and March 31, 2004, respectively; aggregate liquidation preference of $25,175,000 and $45,675,000 at December 31, 2003 and March 31, 2004, respectively     6,426,628     27,224,586     48,432,304  
Stockholders' deficit:                    
Common stock, $0.0001 par value; 12,000,000, 20,000,000 and 30,000,000 shares authorized at December 31, 2002, 2003 and March 31, 2004, respectively; 4,160,621, 4,162,805 and 4,193,355 shares issued and outstanding at December 31, 2002, 2003 and March 31, 2004, respectively     416     416     419  
Additional paid-in-capital     2,809,588     4,960,470     25,962,476  
Accumulated other comprehensive loss         (5,996 )   (7,472 )
Due from officer     (106,584 )   (71,056 )   (35,528 )
Deferred compensation     (1,748,918 )   (3,034,312 )   (3,231,409 )
Accumulated deficit     (5,785,067 )   (15,628,582 )   (39,416,711 )
   
 
 
 
    Total stockholders' deficit     (4,830,565 )   (13,779,060 )   (16,728,225 )
   
 
 
 
Total liabilities, redeemable convertible preferred stock and stockholders' deficit   $ 2,500,105   $ 16,083,581   $ 34,516,265  
   
 
 
 

F-3



MOMENTA PHARMACEUTICALS, INC.

STATEMENTS OF OPERATIONS

 
  Period from
Date of Inception
(May 17, 2001)
through
December 31, 2001

  Years ended
December 31,

  Three Months ended
March 31,

 
 
  2002
  2003
  2003
  2004
 
 
   
   
   
  (Unaudited)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Collaboration revenue   $   $   $ 1,454,287   $   $ 1,036,532  

Operating expenses:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
  Research and development*     206,437     2,173,639     5,347,845     790,143     2,239,770  
  General and administrative*     166,824     2,711,989     4,082,880     705,849     1,409,239  
   
 
 
 
 
 
Total operating expenses     373,261     4,885,628     9,430,725     1,495,992     3,649,009  
   
 
 
 
 
 
Loss from operations     (373,261 )   (4,885,628 )   (7,976,438 )   (1,495,992 )   (2,612,477 )

Interest income

 

 

2,228

 

 

16,965

 

 

73,969

 

 

3,808

 

 

41,635

 
Interest expense             (42,920 )   (5,379 )   (11,068 )
   
 
 
 
 
 
Net loss     (371,033 )   (4,868,663 )   (7,945,389 )   (1,497,563 )   (2,581,910 )
Deemed dividend related to beneficial conversion feature of Series C redeemable convertible preferred stock                     (20,388,696 )

Dividends and accretion to redemption value of redeemable convertible preferred stock

 

 

(21,917

)

 

(520,359

)

 

(1,898,126

)

 

(164,486

)

 

(817,523

)
   
 
 
 
 
 
Net loss attributable to common stockholders   $ (392,950 ) $ (5,389,022 ) $ (9,843,515 ) $ (1,662,049 ) $ (23,788,129 )
   
 
 
 
 
 
Basic and diluted net loss attributable to common stockholders per common share   $ (6.74 ) $ (5.70 ) $ (5.02 ) $ (1.13 ) $ (9.04 )
   
 
 
 
 
 
Shares used in computing basic and diluted net loss attributable to common stockholders per common share     58,280     946,013     1,961,281     1,474,251     2,630,764  
   
 
 
 
 
 
Unaudited pro forma basic and diluted net loss attributable to common stockholders per common share               $ (0.92 )       $ (1.53 )
               
       
 
Shares used in computing unaudited pro forma basic and diluted net loss attributable to common stockholders per common share                 10,717,788           15,550,429  
               
       
 

*Includes stock-based compensation of the following:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
  Research and development   $   $ 47,710   $ 173,102   $ 22,473   $ 90,882  
  General and administrative         348,272     682,576     119,441     317,176  
   
 
 
 
 
 
Total stock-based compensation   $   $ 395,982   $ 855,678   $ 141,914   $ 408,058  
   
 
 
 
 
 

F-4



MOMENTA PHARMACEUTICALS, INC.

STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK
AND STOCKHOLDERS' EQUITY (DEFICIT)

Period from Inception (May 17, 2001) through December 31, 2003

 
  Redeemable Convertible
Preferred Stock

  Common Stock
   
   
   
   
   
   
 
 
   
  Accumulated
Other
Comprehensive
Loss

   
   
   
  Total
Stockholders'
Equity
(Deficit)

 
 
   
  Par
Value

  Additional
Paid-in
Capital

  Due from Officer
  Deferred
Stock
Compensation

  Accumulated
Deficit

 
 
  Shares
  Amount
  Shares
 
Issuance of common stock to founders             2,680,002   $ 268   $ (59 )                         $ 209  
Sale of Series A Redeemable Convertible Preferred Stock, net of offering costs of $20,880 and value ascribed to warrants of $232,215   250,000                   $ 232,215                     $ (3,095 )   229,120  
Issuance of common stock to nonemployees             197,368     19     15,400                             15,419  
Accretion of Preferred Stock to redemption value       $ 12,533                                       (12,533 )   (12,533 )
Preferred Stock dividends         9,384                                       (9,384 )   (9,384 )
Net loss                                                 (371,033 )   (371,033 )
   
 
 
 
 
 
 
 
 
 
 
Balances at December 31, 2001 (carried forward)   250,000   $ 21,917   2,877,370   $ 287   $ 247,556   $   $   $   $ (396,045 ) $ (148,202 )

F-5


Balances at December 31, 2001 (brought forward)   250,000   $ 21,917   2,877,370   $ 287   $ 247,556   $   $   $   $ (396,045 ) $ (148,202 )

Sale of Series A Prime Redeemable Convertible Preferred Stock, net of offering costs of $20,351

 

893,537

 

 

1,504,649

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Sale of Series A Double Prime Redeemable Convertible Preferred Stock, net of offering costs of $20,297   1,533,101     4,379,703                                                
Sale of common stock             1,071,069     108     1,017                             1,125  
Issuance of common stock for license fee             177,628     18     278,914                             278,932  
Issuance of common stock to nonemployees             30,800     3     448                             451  
Issuance of common stock pursuant to the exercise of stock options             3,754           293                             293  
Accretion of Preferred Stock to redemption value         39,044                                       (39,044 )   (39,044 )
Preferred Stock dividends         481,315                                       (481,315 )   (481,315 )
Issuance of warrant in conjunction with equipment line financing                         29,875                             29,875  
Sale of restricted common stock                         106,584           (106,584 )                  
Deferred stock compensation expense associated with stock options                         2,108,516                 (2,108,516 )            
Amortization of deferred stock compensation                                           359,598           359,598  
Compensation expense associated with options issued to nonemployees                         36,385                             36,385  
Net loss                                                 (4,868,663 )   (4,868,663 )
   
 
 
 
 
 
 
 
 
 
 
Balances at December 31, 2002 (carried forward)   2,676,638   $ 6,426,628   4,160,621   $ 416   $ 2,809,588   $   $ (106,584 ) $ (1,748,918 ) $ (5,785,067 ) $ (4,830,565 )

F-6


Balances at December 31, 2002 (brought forward)   2,676,638   $ 6,426,628   4,160,621   $ 416   $ 2,809,588   $   $ (106,584 ) $ (1,748,918 ) $ (5,785,067 ) $ (4,830,565 )

Sale of Series B Redeemable Convertible Preferred Stock, net of offering costs of $100,168

 

6,440,678

 

 

18,899,832

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Issuance of common stock pursuant to the exercise of stock options             23,360     2     5,053                             5,055  
Accretion of Preferred Stock to redemption value         52,132                                       (52,132 )   (52,132 )
Preferred Stock dividends         1,845,994                                       (1,845,994 )   (1,845,994 )
Payment of officer obligation                                     35,528                 35,528  
Deferred stock compensation expense associated with stock options                         1,956,672                 (1,956,672 )            
Amortization of deferred stock compensation                                           671,278           671,278  
Compensation expense associated with options issued to nonemployees                         184,400                             184,400  
Repurchase of unvested restricted stock             (21,176 )   (2 )                                 (2 )
Vesting of restricted stock                         4,757                             4,757  
Unrealized loss on short-term investments                               (5,996 )                     (5,996 )
Net loss                                                 (7,945,389 )   (7,945,389 )
                                                     
 
Comprehensive loss                                                       (7,951,385 )
   
 
 
 
 
 
 
 
 
 
 
Balances at December 31, 2003   9,117,316   $ 27,224,586   4,162,805   $ 416   $ 4,960,470   $ (5,996 ) $ (71,056 ) $ (3,034,312 ) $ (15,628,582 ) $ (13,779,060 )

F-7



MOMENTA PHARMACEUTICALS, INC.

STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK
AND STOCKHOLDERS' EQUITY (DEFICIT)

Period from Inception (May 17, 2001) through March 31, 2004

 
  Redeemable Convertible
Preferred Stock

  Common Stock
   
   
   
   
   
   
 
 
   
  Accumulated
Other
Comprehensive
Loss

   
   
   
  Total
Stockholders'
Equity
(Deficit)

 
 
   
  Par
Value

  Additional
Paid-in
Capital

  Due from Officer
  Deferred
Stock
Compensation

  Accumulated
Deficit

 
 
  Shares
  Amount
  Shares
 
Balances at December 31, 2003 (brought forward)   9,117,316   $ 27,224,586   4,162,805   $ 416   $ 4,960,470   $ (5,996 ) $ (71,056 ) $ (3,034,312 ) $ (15,628,582 ) $ (13,779,060 )

Sale of Series C Redeemable Convertible Preferred Stock, net of offering costs of $109,805 (unaudited)

 

2,612,696

 

 

20,390,195

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Beneficial conversion feature
of Series C (unaudited)
                        20,388,696                       (20,388,696 )      
Issuance of common stock pursuant to the exercise of stock options (unaudited)             30,550     3     6,921                             6,924  
Accretion of Preferred Stock to redemption value (unaudited)         17,315                                       (17,315 )   (17,315 )
Preferred Stock dividends (unaudited)         800,208                                       (800,208 )   (800,208 )
Payment of officer obligation (unaudited)                                     35,528                 35,528  
Deferred stock compensation expense associated with stock options (unaudited)                         469,418                 (469,418 )            
Amortization of deferred stock compensation (unaudited)                                           272,321           272,321  
Compensation expense associated with options issued to nonemployees (unaudited)                         135,737                             135,737  
Vesting of restricted stock (unaudited)                         1,234                             1,234  
Change in unrealized loss on short-term investments (unaudited)                               (1,476 )                     (1,476 )
Net loss (unaudited)                                                 (2,581,910 )   (2,581,910 )
                                                     
 
Comprehensive loss (unaudited)                                                       (2,583,386 )
   
 
 
 
 
 
 
 
 
 
 
Balances at March 31, 2004 (unaudited)   11,730,012   $ 48,432,304   4,193,355   $ 419   $ 25,962,476   $ (7,472 ) $ (35,528 ) $ (3,231,409 ) $ (39,416,711 ) $ (16,728,225 )
   
 
 
 
 
 
 
 
 
 
 

F-8



MOMENTA PHARMACEUTICALS INC.

STATEMENTS OF CASH FLOWS

 
  Period from
Date of Inception
(May 17, 2001)
through
December 31, 2001

  Years ended
December 31,

  Three months
ended March 31,

 
 
  2002
  2003
  2003
  2004
 
 
   
   
   
  (Unaudited)

 
Operating activities:                                
Net loss   $ (371,033 ) $ (4,868,663 ) $ (7,945,389 ) $ (1,497,563 ) $ (2,581,910 )
Adjustments to reconcile net loss to net cash used in operations:                                
  Depreciation     438     84,320     252,497     53,911     103,688  
  Stock compensation expense     15,420     395,982     855,678     141,914     408,058  
  Noncash license expense         278,932              
  Noncash interest expense             9,128     1,658     11,068  
  Amortization of premium on investments                             54,463  
  Changes in operating assets and liabilities:                                
    Unbilled collaboration revenue             (2,018,380 )       1,018,636  
    Prepaid expenses and other current assets     (718   (22,543 )   (238,290 )   53,136     (899,923 )
    Other assets         (108,586 )   29,066     45,631     (20,466 )
    Accounts payable     33,334     254,181     516,622     (172,262 )   (206,330 )
    Accrued expenses     277,012     326,627     (32,772 )   (9,763 )   497,159  
    Deferred revenue             564,093         (36,789 )
   
 
 
 
 
 
Net cash used in operating activities     (45,547 )   (3,659,750 )   (8,007,747 )   (1,383,338 )   (1,652,346 )

Investing activities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Purchases of property and equipment     (2,627 )   (949,960 )   (501,875 )   (100,956 )   (41,565 )
Purchases of marketable securities             (8,001,902 )       (7,426,191 )
Maturities of marketable securities                     750,000  
   
 
 
 
 
 
Net cash used in investing activities     (2,627 )   (949,960 )   (8,503,777 )   (100,956 )   (6,717,756 )

Financing activities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Proceeds from issuance of redeemable convertible preferred stock, net of cash paid for issuance costs     229,120     5,884,352     18,899,832         20,390,195  
Proceeds from line of credit             1,002,278     919,989      
Payments on line of credit             (289,049 )   (51,197 )   (89,743 )
Payment of officer obligation             35,528     35,528     35,528  
Proceeds from issuance of common stock     209     14,757     5,055     850     6,924  
   
 
 
 
 
 
Net cash provided by financing activities     229,329     5,899,109     19,653,644     905,170     20,342,904  
   
 
 
 
 
 
Net increase (decrease) in cash and cash equivalents     181,155     1,289,399     3,142,120     (579,124 )   11,972,802  
Cash and cash equivalents at beginning of period         181,155     1,470,554     1,470,554     4,612,674  
   
 
 
 
 
 
Cash and cash equivalents at end of period   $ 181,155   $ 1,470,554   $ 4,612,674   $ 891,430   $ 16,585,476  
   
 
 
 
 
 

Supplemental disclosure of cash flow information:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Interest paid           $ 33,792   $ 3,719   $ 8,578  
   
 
 
 
 
 

F-9



MOMENTA PHARMACEUTICALS, INC.

NOTES TO FINANCIAL STATEMENTS

1.    The Company

Business

        Momenta Pharmaceuticals, Inc. (the "Company" or "Momenta") was incorporated in the state of Delaware on May 17, 2001. Its facilities are located in Cambridge, Massachusetts. Momenta is a biotechnology company specializing in the sequencing and engineering of complex sugars for the development of improved versions of existing drugs, the development of novel drugs and the discovery of new biological processes.

        Momenta is subject to risks common to companies in the biotechnology industry including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing and compliance with FDA and other government regulations.

        Prior to 2003, the Company did not generate any revenue and operated as a development-stage company for financial statement reporting purposes. Effective 2003, the Company ceased to be considered a development-stage company for financial statement reporting purposes as a result of the collaboration agreement with the Sandoz N.V. and Sandoz Inc., each an affiliate of Novartis AG ("Sandoz") (see Note 3).

Basis of Presentation

        The financial statements as of March 31, 2004 and for the three months ended March 31, 2003 and 2004 have been prepared in accordance with generally accepted accounting principles for interim financial information and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, consisting only of normal recurring accruals, considered necessary for a fair presentation of the results of these interim periods have been included. The results of operations for the three months ended March 31, 2004 are not necessarily indicative of the results that may be expected for the full year. All financial statement amounts and disclosures related to the three month periods ended March 31, 2003 and 2004 are unaudited.

        On May 10, 2004, the Company's Board of Directors authorized a 1.28-for-1 common stock split effected in the form of a common stock dividend. All common share and per share information in the accompanying financial statements has been retroactively restated to reflect such common stock split.

2.    Summary of Significant Accounting Policies

Use of Estimates

        The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ materially from those estimates.

Cash, Cash Equivalents, and Short-Term Investments

        The Company invests its excess cash in bank deposits, money market accounts, corporate debt securities, and U.S. government obligations. The Company considers all highly liquid investments purchased with maturities of three months or less from the date of purchase to be cash equivalents.

F-10



Cash equivalents are carried at fair value, which approximates cost, and primarily consist of money market funds maintained at major U.S. financial institutions.

        All short-term investments, which primarily represent marketable debt securities, have been classified as "available-for-sale." Purchased premiums or discounts on debt securities are amortized to interest income through the stated maturities of the debt securities. Management determines the appropriate classification of its investments in debt securities at the time of purchase and evaluates such designation as of each balance sheet date. Unrealized gains and losses are included in accumulated other comprehensive loss and reported as a separate component of stockholders' deficit. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in interest income. The cost of securities sold is based on the specific identification method. Interest earned on short-term investments is included in interest income.

Credit Risks and Concentrations

        Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash equivalents and marketable securities. The Company has established guidelines relating to diversification and maturities that allows the Company to manage risk.

Fair Value of Financial Instruments

        The carrying amounts of the Company's financial instruments, which include cash equivalents, accounts payable and other accrued expenses, approximate their fair values due to their short maturities. The carrying amount of the Company's line of credit obligations approximates its fair value due to its variable interest rate.

Property and Equipment

        Property and equipment is stated at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the assets which range from three to seven years. Leasehold improvements are amortized over the estimated useful lives of the assets or related lease terms, whichever is shorter.

Long-Lived Assets

        The Company evaluates the recoverability of its property and equipment and other long-lived assets when circumstances indicate that an event of impairment may have occurred in accordance with the provisions of Statement of Financial Account Standards ("SFAS") No. 144, Accounting for the Impairment of Disposal of Long-Lived Assets (SFAS No. 144). SFAS No. 144 further refines the requirements of SFAS No. 121, Accounting for the Impairment of Long-Lived Assets and Long-Lived Assets to be Disposed of , that companies (1) recognize an impairment loss only if the carrying amount of a long-lived asset is not recoverable based on its undiscounted future cash flows and (2) measure an impairment loss as the difference between the carrying amount and fair value of the asset. Impairment is measured based on the difference between the carrying value of the related assets or businesses and the undiscounted future cash flows of such assets or businesses. In addition, SFAS No. 144 provides guidance on accounting and disclosure issues surrounding long-lived assets to be disposed of by sale. No impairment charges have been required to be recognized through December 31, 2003.

F-11



Revenue Recognition

        Revenues associated with the Company's collaboration with Sandoz include an initial payment, reimbursement of development services and expenses, and potential future milestones and royalties. The initial payment represented reimbursement of specific development costs incurred prior to the date of the collaboration. Amounts earned under the collaboration agreement are not refundable if the research or development is unsuccessful. To date, the Company has not earned any milestones or royalties.

        The Company uses revenue recognition criteria outlined in Staff Accounting Bulletin ("SAB") No. 101, Revenue Recognition in Financial Statements , as revised by SAB No. 104, Revenue Recognition , and Emerging Issues Task Force ("EITF") Issue 00-21 Revenue Arrangements with Multiple Deliverables (EITF 00-21). Accordingly, revenues from licensing agreements are recognized based on the performance requirements of the agreement. Non-refundable up-front fees, where the Company has an ongoing involvement or performance obligation, are generally recorded as deferred revenue in the balance sheet and amortized into collaboration revenue in the statement of operations over the term of the performance obligation. Revenues from research and development services and expenses are recognized in the period the services are performed and the reimbursable costs are incurred.

Research and Development

        Research and development costs are expensed as incurred. Research and development costs include wages, benefits, facility and other research-related overhead expenses, as well as license fees and contracted research and development activities.

Stock-Based Compensation

        The Company has elected to account for its stock-based compensation plans following Accounting Principles Board Opinion No. 25, Accounting for Stock Issued to Employees (APB 25), and related interpretations, rather than the alternative fair value accounting provided under SFAS No. 123, Accounting for Stock-Based Compensation (SFAS 123). In accordance with EITF 96-18, Accounting for Equity Instruments that are Issued to Other than Employees for Acquiring, or in Connection with Selling Goods or Services (EITF 96-18), the Company records compensation expense equal to the fair value of options granted to non-employees over the vesting period, which is generally the period of service.

        Pro forma information regarding net loss is required by SFAS 123 as if the Company had accounted for its stock-based awards to employees under the fair value method of SFAS 123. The fair value of the Company's stock options used to compute pro forma net loss is the estimated value at the grant date using the Black-Scholes option-pricing model with the following weighted-average assumptions for the period from inception (May 17, 2001) through December 31, 2001 (Fiscal 2001) and the fiscal years ended December 31, 2002 and 2003 (Fiscal 2002 and 2003, respectively):

 
  2001
  2002
  2003
 
Risk-free interest rate   4.6 % 4.5 % 3.5 %
Expected volatility   80 % 80 % 80 %
Expected lives   7 years   7 years   7 years  
Expected dividend        

        The per-share, weighted-average grant date fair value of options granted during Fiscal 2001, 2002 and 2003 were $0.06, $1.45 and $3.53, respectively.

F-12



        For purposes of pro forma disclosures, the estimated fair value of the options is amortized over the vesting period of the options. Had compensation expense for the Company's stock-based compensation plans been determined based on the fair value at the grant dates for awards under those plans consistent with the method of SFAS 123, the Company's net loss for fiscal 2001, 2002 and 2003 would have been as follows:

 
   
   
   
  Three Months
Ended March 31,

 
 
  2001
  2002
  2003
  2003
  2004
 
 
   
   
   
  (unaudited)

 
Net loss attributable to common stockholders as reported   $ (392,950 ) $ (5,389,022 ) $ (9,843,515 ) $ (1,662,049 ) $ (23,788,129 )
Add: Stock-based employee compensation expense included in reported net loss         52,452     280,460     38,562     174,617  
Deduct: Stock-based employee compensation expense determined under fair value based method     (13 )   (34,687 )   (280,090 )   (36,390 )   (133,537 )
   
 
 
 
 
 
SFAS 123 Pro forma net loss   $ (392,963 ) $ (5,371,257 ) $ (9,843,145 ) $ (1,659,877 ) $ (23,747,049 )
   
 
 
 
 
 
Basic and diluted net loss per share                                
  As reported   $ (6.74 ) $ (5.70 ) $ (5.02 ) $ (1.13 ) $ (9.04 )
  SFAS 123 Pro forma   $ (6.74 ) $ (5.68 ) $ (5.02 ) $ (1.13 ) $ (9.03 )

Redeemable Convertible Preferred Stock

        The carrying value of redeemable convertible preferred stock will be increased by periodic accretions so that the carrying amount will equal the redemption value at the redemption date. These accretions will be effected through charges against accumulated deficit. As discussed in Note 7, the holders of Series A, Series A Prime, Series A Double Prime, Series B and Series C Redeemable Convertible Preferred Stock are entitled to dividends at 10% per annum through each redemption date, payable only upon redemption.

Income Taxes

        The Company accounts for income taxes under SFAS No. 109, Accounting for Income Taxes . Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates that will be in effect when the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that the deferred tax asset will not be recovered.

Comprehensive Loss

        The Company reports comprehensive loss in accordance with SFAS No. 130, Reporting Comprehensive Income (SFAS 130). SFAS 130 establishes rules for the reporting and display of comprehensive loss and its components. Accumulated other comprehensive loss as of December 31, 2003 consists entirely of unrealized losses on available-for-sale securities. Comprehensive loss for Fiscal 2001 and 2002 equaled net loss.

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Net Loss Per Share

        The Company computes net loss per share in accordance with SFAS No. 128, Earnings per Share (SFAS No. 128). Under the provisions of SFAS 128, basic net loss per common share is computed by dividing net loss by the weighted-average number of common shares outstanding. Diluted net loss per common share is computed by dividing net loss by the weighted-average number of common shares and dilutive common share equivalents then outstanding. Common equivalent shares consist of the incremental common shares issuable upon the conversion of preferred stock, shares issuable upon the exercise of stock options and the conversion of preferred stock upon the exercise of warrants. The Company has excluded the impact of all convertible preferred stock, stock options and shares of common stock subject to repurchase from the calculation of historical diluted net loss per common share because all such securities are antidilutive for all periods presented. The total number of shares excluded from the calculations of historical diluted net loss per share was 2,684,116, 6,622,196 and 14,332,014 for Fiscal 2001, 2002 and 2003, respectively.

Unaudited Pro Forma Net Loss Per Share

        Unaudited pro forma net loss per share is computed using the weighted average number of common shares outstanding, including the pro forma effects of the automatic conversion of all redeemable convertible preferred stock outstanding as of March 31, 2004, into shares of the Company's common stock effective upon the assumed closing of the Company's proposed initial public offering, as if such conversion had occurred at the date of the original issuance.

Segment Reporting

        The Company has adopted SFAS No. 131, Disclosure About Segments of an Enterprise and Related Information , which requires companies to report selected information about operating segments, as well as enterprisewide disclosures about products, services, geographical areas, and major customers. Operating segments are determined based on the way management organizes its business for making operating decisions and assessing performance. The Company has only one operating segment, the discovery, development and commercialization of drug products.

Recently Issued Accounting Standards

        In January 2003, the FASB issued Financial Interpretation Number 46, Consolidation of Variable Interest Entities (FIN 46). This interpretation requires existing unconsolidated variable interest entities to be consolidated by their primary beneficiaries if the entities do not effectively disperse risks among parties involved. It explains how to identify variable interest entities and how an enterprise assesses its interest in a variable interest entity to decide whether to consolidate that entity. This interpretation, as amended, applies in the first fiscal year or interim period beginning after December 15, 2003, to variable interest entities in which an enterprise holds a variable interest that it acquired before February 1, 2003. Since the Company does not currently have any unconsolidated variable interest entities, the Company does not expect the adoption of FIN 46 to have a material impact on its financial position or results of operations.

        In May 2003, the FASB issued SFAS No. 150, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity. This statement establishes how a company classifies and measures certain financial instruments with characteristics of both liabilities and equity, including redeemable preferred stock. This statement is effective for financial instruments entered into or

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modified after May 31, 2003, and otherwise effective at the beginning of the interim period commencing July 1, 2003, except for mandatory redeemable financial instruments of nonpublic companies, which is effective for fiscal periods beginning after December 31, 2004. The Company does not expect the adoption of this statement will have a material impact on its financial statements.

3.    Collaboration and License Agreements

Sandoz

        In November 2003, we entered into a collaboration and license agreement with Sandoz to jointly develop and commercialize M-Enoxaparin, a generic version of Lovenox, a low molecular weight heparin. Under the terms of this agreement, we and Sandoz agree to exclusively work with each other to develop and commercialize M-Enoxaparin for medical indications within the United States.

        Under this collaboration, Sandoz will pay us for scientific, technical and/or management services. Sandoz is also responsible for funding substantially all of the other ongoing development and commercialization costs and legal expenses incurred with respect to M-Enoxaparin, subject to an agreed-upon limit. As of December 31, 2003, we have recorded unbilled collaboration revenue of $2.0 million, including $0.6 million for an initial payment (for reimbursement of development costs we incurred prior to signing the agreement) and $1.4 million for personnel and other reimburseable development costs. The unbilled receivable of $2.0 million was subsequently billed and is due in the first quarter of 2004. The initial payment was deferred and is being amortized into revenue over the development period, estimated to be four years. Of this amount, $24,526 was recorded as revenue in 2003. The personnel and other reimbursable costs were recorded as revenue in 2003. Upon commercialization, Sandoz will share profits with us or pay royalties to us on net sales of M-Enoxaparin in the United States. Sandoz may also make additional payments to us up to an aggregate of $55.0 million, upon our achievement of a specific regulatory milestone and a series of annual commercial milestones. If the development and commercialization costs and legal expenses, in the aggregate, exceed a specified amount, Sandoz is permitted to offset a portion of the excess against the profit-sharing amounts, the royalties and the commercial milestone payments.

        We have granted Sandoz the right to negotiate additional rights under certain circumstances, including an exclusive license to develop and commercialize M-Enoxaparin outside of the United States.

Massachusetts Institute of Technology

        In December 2001, we entered into an exclusive patent license agreement with the Massachusetts Institute of Technology ("M.I.T."), that was subsequently amended and restated in early November 2002 and further amended in 2003 and 2004. We entered into an additional exclusive patent license agreement with M.I.T. in late October 2002. These two agreements grant us various exclusive and nonexclusive worldwide licenses, with the right to grant sublicenses, under certain patents and patent applications relating to methods and technologies for analyzing and characterizing sugars and certain heparins, heparinases and other enzymes and synthesis methods. Subject to typical retained rights of M.I.T. and the United States government, we are granted exclusive rights under certain of these patents and applications in certain fields.

        In exchange for these rights, we paid M.I.T. a license issue fee and we pay annual license maintenance fees. We are also required to pay M.I.T. royalties on products and services covered by the licenses and sold by us or our affiliates or sublicensees, a percentage of certain other income received

F-15



by us from corporate partners and sublicensees, and certain patent prosecution and maintenance costs. M.I.T. and certain contributing individuals were also issued shares of our common stock. We made payments of $0.3 million to M.I.T. in Fiscal 2002 and 2003.

        Pursuant to the license agreement, the Company issued an aggregate of 197,356 shares of common stock to M.I.T. and certain of its affiliates (the "University Stockholders"). In connection with the issuance of common stock, the Company recorded $15,420 in research and development expense during 2001 representing the fair market value of the common stock at the time of issuance. Subject to certain conditions, the University Stockholders were entitled to additional shares of common stock, such that the University Stockholders' ownership of the Company's outstanding common stock, in the aggregate, would not be less than 5% on a fully-diluted basis. Such additional shares were to be issued on the date upon which the Company received a total of $5.0 million in cash in exchange for the Company's capital stock. On April 16, 2002, the Company reached such $5.0 million equity threshold and distributed an aggregate of 177,632 additional shares of common stock to the University Stockholders. Upon such distribution, all rights to further issuances were terminated. In connection with the issuance of common stock, the Company recorded $278,932 in research and development expense during Fiscal 2002 representing the fair market value of the common stock at the time of issuance.

        If, due to our failure to meet diligence obligations, M.I.T. converts certain of our exclusive licenses to non-exclusive, or if M.I.T. terminates one of the agreements, M.I.T. will honor the exclusive nature of the sublicense we granted to Sandoz so long as Sandoz both continues to fulfill its obligations to us under the collaboration and license agreement and agrees to assume our rights and obligations to M.I.T.

The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory

        In November 2002, we entered into an agreement with The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory ("Lawrence Berkeley National Lab") under which we licensed certain patents and applications covering the metabolic synthesis of sugars and glycoconjugates and were granted an exclusive license, with the right to grant sublicenses, for the synthesis, production or modification of sugars and glycoconjugates in or on biological molecules for purposes of researching, developing and commercializing products, services and processes for all human therapeutic applications, excluding the sale of research reagents.

        After November 20, 2004, we may retain the license under this broad field if we have met certain diligence obligations and pay a fee. If we do not do so, the field narrows to three therapeutic applications that we select from an agreed upon list, each to be more thoroughly defined through negotiation.

        In return for these license rights, we paid Lawrence Berkeley National Lab a license issue fee, and we must pay royalties, subject to annual minimum amounts. If we sublicense our rights, we also pay a percentage of the fees received from our sublicensees. We are also responsible for patent prosecution and maintenance costs. We made payments to Lawrence Berkeley National Lab in Fiscal 2002 and 2003 of $20,000 and $59,352, respectively.

Siegfried (U.S.A.), Inc. and Siegfried Ltd.

        In October 2003, we entered into a process development and production agreement with Siegfried (U.S.A), Inc. and Siegfried Ltd. ("Siegfried") under which we provide to Siegfried our existing

F-16



laboratory-scale processes and analytical methods for the production of enoxaparin. Siegfried's responsibility is to further develop the processes and, once we approve of such processes, manufacture the active pharmaceutical ingredient enoxaparin sodium for use in stability, preclinical, and clinical studies and for other development purposes. We paid Siegfried $0.2 million for services in Fiscal 2003.

Parivid LLC (Unaudited)

        On March 24, 2004, we entered into a three year collaboration agreement with Parivid LLC ("Parivid") under which each party cross licensed certain intellectual property. The agreement allows us to annually fund up to $1,250,000 of sponsored research and is cancelable by either party upon 45 days notice. Under certain circumstances, we may be responsible for $5 million of milestone payments and royalty payments on sales of certain of our products.

4. Financial Instruments

        The following is a summary of cash, cash equivalents, and short-term investments as of December 31, 2002 and 2003:

December 31, 2002

  Cost
  Gross
Unrealized
Gains

  Gross
Unrealized
Losses

  Fair Value
Cash   $ 1,470,554   $   $   $ 1,470,554
   
 
 
 
Reported as:                        
  Cash and cash equivalents   $ 1,470,554   $   $   $ 1,470,554
   
 
 
 
December 31, 2003

  Cost
  Gross
Unrealized
Gains

  Gross
Unrealized
Losses

  Fair Value
Cash   $ 261,126   $   $   $ 261,126
Money market funds     1,846,025             1,846,025
Corporate debt securities     10,505,769         (5,996 )   10,499,773
   
 
 
 
    $ 12,612,920   $   $ (5,996 ) $ 12,606,924
   
 
 
 
Reported as:                        
  Cash and cash equivalents   $ 4,614,179   $   $ (1,505 ) $ 4,612,674
  Short-term investments     7,998,741         (4,491 )   7,994,250
   
 
 
 
    $ 12,612,920   $   $ (5,996 ) $ 12,606,924
   
 
 
 

        At December 31, 2003, all short-term investments have remaining contractual maturities of less than twelve months. The unrealized losses at December 31, 2003 are not believed to be other-than-temporary.

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5. Property and Equipment

        At December 31, 2002 and 2003, property and equipment, net consists of the following:

 
  2002
  2003
 
Computer equipment   $ 113,821   $ 140,306  
Office furniture and equipment     8,397     14,219  
Laboratory equipment     695,844     1,082,526  
Leasehold improvements     134,525     217,411  
Less: accumulated depreciation     (84,758 )   (337,256 )
   
 
 
    $ 867,829   $ 1,117,206  
   
 
 

        Depreciation expense amounted to $438, $84,320 and $252,497 for Fiscal 2001, 2002 and 2003, respectively.

6. Accrued Expenses

        At December 31, 2002 and 2003, accrued expenses consisted of the following:

 
  2002
  2003
Accrued compensation   $ 226,462   $ 209,742
Accrued contracted research costs     6,925     102,630
Accrued license fees     214,808     59,051
Accrued professional fees     147,781     90,560
Other     7,663     108,884
   
 
    $ 603,639   $ 570,867
   
 

7. Redeemable Convertible Preferred Stock and Stockholders' Equity

        Redeemable convertible preferred stock is summarized below:

 
  Shares Designated
  Shares
Issued and
Outstanding

  Per Share
Liquidation
Preference

  Aggregate
Liquidation
Preference

Series A   250,000   250,000   $ 1.00   $ 250,000
Series A Prime   893,537   893,537     1.7067     1,525,000
Series A Double Prime   1,545,601   1,533,101     2.87     4,400,000
Series B   6,440,678   6,440,678     2.95     19,000,000
   
 
       
Balance at December 31, 2003   9,129,816   9,117,316         $ 25,175,000
Series C (unaudited)   2,612,696   2,612,696     7.8463     20,500,000
   
 
       
Balance at March 31, 2004 (unaudited)   11,742,512   11,730,012         $ 45,675,000
   
 
       

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        The carrying value of redeemable convertible preferred stock, reflecting dividends and accretion to redemption value, is summarized below:

 
  December 31,
  March 31,
 
  2002
  2003
  2004
 
   
   
  (Unaudited)
Series A   $ 80,721   $ 139,525   $ 154,226
Series A Prime     1,650,524     1,806,281     1,845,220
Series A Double Prime     4,695,383     5,138,766     5,249,612
Series B         20,140,014     20,620,022
Series C             20,563,224
   
 
 
    $ 6,426,628   $ 27,224,586   $ 48,432,304
   
 
 

Dividends

        The holders of Series A Redeemable Convertible Preferred Stock (Series A Preferred), Series A Prime Redeemable Convertible Preferred Stock (Series A Prime Preferred), Series A Double Prime Redeemable Convertible Preferred Stock (Series A Double Prime Preferred), Series B Redeemable Convertible Preferred Stock (Series B Preferred) and Series C Redeemable Convertible Preferred Stock (Series C Preferred), collectively the Preferred Stock, are entitled to receive dividends equal to any dividend paid on the Company's Common Stock. The holders of the Preferred Stock are entitled to dividends at 10% per annum through each redemption date, payable only upon redemption.

Liquidation Preference

        In the event of a liquidation, either voluntary or involuntary, dissolution or winding up of the affairs of the Company, the holders of Preferred Stock are entitled to receive their stated per share liquidation preference value, adjusted for any stock splits or dividends, combinations or other recapitalizations affecting such series, plus all declared but unpaid dividends before any payment is made to the holders of Common Stock. If the assets of the Company are insufficient to pay the full preferential amount to holders of each of the series of Preferred Stock, the assets are distributed ratably among the holders of Preferred Stock in proportion to the full preferential amount each holder is otherwise entitled to receive. After full payment has been made to the holders of all series of Preferred Stock, all remaining assets are distributed to holders of Common Stock.

Conversion

        Each share of Preferred Stock is convertible at any time into that number of shares of Common Stock that results from dividing $1.00, $1.7067, $2.87, $2.95 and $7.8463 for the Series A Preferred, the Series A Prime Preferred, the Series A Double Prime Preferred, the Series B Preferred and the Series C Preferred, respectively, by the then-applicable conversion price for each series of Preferred Stock in effect at the time of conversion, adjustable for certain dilutive events. The applicable conversion price was $0.78, $1.33, $2.24, $2.31 and $6.13 for the Series A Preferred, the Series A Prime Preferred, the Series A Double Prime, the Series B Preferred and the Series C Preferred, respectively. Each share of Preferred Stock automatically converts, at the conversion rate described above, upon an initial public offering resulting in gross proceeds to the Company of at least $15,000,000 at a per share

F-19



price to the public of at least $7.81 per share. Notwithstanding the foregoing, in the event that (i) the pricing committee of the board of directors approves a per share price in connection with a firm commitment underwritten offering at less than $7.81 per share, (ii) 66 2 / 3 % of the shares of Preferred Stock approve such adjusted price and (iii) the adjusted price is no less than $6.1299, each share of Preferred Stock shall automatically convert into shares of common stock.

        Each share of Series A Preferred, Series A Prime Preferred, Series A Double Prime Preferred, Series B Preferred and Series C Preferred automatically converts upon the written consent of 66 2 / 3 % or more of the shares of such Preferred Stock outstanding at that time.

Voting Rights

        Each holder of Preferred Stock is entitled to the number of votes equal to the number of whole shares of Common Stock into which the shares of the particular series of Preferred Stock are convertible.

Redemption

        Upon the demand of a majority of shares of a series of Preferred Stock, each stockholder of such series has the right to require redemption of such preferred stockholder's shares. If the funds of the Company are insufficient to redeem the total number of shares on any date, the holders of such shares share ratably in any funds available for redemption based on the respective amounts that they would have been entitled to receive.

        Each holder of the respective series of the Preferred Stock has the right to cause the Company, on May 9, 2008, May 9, 2009 and May 9, 2010 to redeem, on a cumulative basis, from each such holder of shares at the redemption price of each respective series, 33 1 / 3 %, 66 2 / 3 % and 100%, respectively, of the outstanding shares of the various Preferred Stock. The redemption price is equal to the price originally paid per share for each respective series of Preferred Stock plus dividends of 10% per annum through the redemption date. The Company is accreting dividends for the Preferred Stock to their respective redemption values assuming redemption occurs at the earliest date permitted.

8. Warrants

        On August 16, 2001, in connection with the Series A Preferred offering, the Company issued warrants (the Series A Prime Preferred Warrants) to purchase an aggregate of 585,926 shares of Series A Prime Preferred at an exercise price of $1.7067 per share.

        The fair market value ($232,215) of the Series A Prime Preferred Warrants on their issuance date was recorded as a reduction in the carrying amount of the Series A Preferred. This reduction will be accreted to retained earnings ratably over the period from the warrant issuance through the Series A Preferred redemption dates. The fair value was estimated using the Black-Scholes model with the following assumptions: 0.00% dividend yield, 80% volatility, 4.49% risk-free interest rate and an expected term of 0.44 years. These warrants were exercised or terminated in 2002.

        In 2002, in connection with a bank line of credit agreement, the Company granted a warrant to purchase 12,500 shares of Series A Double Prime Redeemable Convertible Preferred Stock at an exercise price of $2.87 per share. This warrant was immediately exercisable and expires in December 2012. The fair value of the warrant was estimated to be $29,875, which was recorded as

F-20



additional paid-in capital and as prepaid interest at December 31, 2002. This prepaid interest amount is being amortized as interest expense over the 36-month term of the line of credit. The fair value was estimated using the Black-Scholes model with the following assumptions: 0% dividend yield, 80% volatility, 3.92% risk-free interest rate and an expected term of ten years (equal to the life of the warrant).

9. Common Stock

        Holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders of the Company.

        Shares of common stock reserved for future issuance are as follows:

 
  December 31,
 
  2002
  2003
Common stock:        
  Conversion of convertible preferred stock   3,426,097   11,670,165
  Exercise of outstanding options and warrant   448,898   1,046,694
  Shares available for grant under stock option plans   880,035   249,254
   
 
    4,755,030   12,966,113
   
 

Share Restriction Agreements

        On June 13, 2001, the Company entered into Restricted Stock Purchase Agreements with certain employees and nonemployees to purchase an aggregate of 2,680,003 shares of common stock. Each Restricted Stock Purchase Agreement provides for the repurchase of common stock held by these individuals and entities by the Company at a rate of $0.0001 per share, the original purchase price, adjustable for certain dilutive events, until the shares vest. The repurchase provisions lapse over a 45-month period commencing on September 13, 2001, provided that each individual and entity subject to such agreements continues service with the Company.

        During 2002, the Company entered into Restricted Stock Purchase Agreements with two officers and a nonemployee to purchase an aggregate of 1,101,870 shares of common stock. Pursuant to one of the Restricted Stock Purchase Agreements, 980,859 shares of common stock were sold to an officer for $106,662. The purchase price is payable ratably over approximately three years and is included in stockholders' deficit as Due from Officer. Each Restricted Stock Purchase Agreement provides for the repurchase of common stock held by these individuals and entities by the Company at a price equal to the original price paid, adjustable for certain dilutive events, until the shares vest. The repurchase provisions generally lapse over a three-to four-year period provided that each individual and entity subject to such agreements continues service with the Company.

        At December 31, 2002 and 2003, there were 2,763,201 and 1,631,155 shares of unvested restricted common stock outstanding, respectively. The weighted-average fair value of restricted stock granted during fiscal 2001 and 2002 was $0.0001 and $1.57 per share, respectively.

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10. Stock Option Plan

        The Company's 2002 Stock Incentive Plan, as amended, provides for the granting of stock options and restricted stock to employees, officers, directors, consultants and advisors to purchase the Company's Common Stock. As of December 31, 2003, the Company was authorized to issue options to purchase 1,316,687 shares of Common Stock under the 2002 Stock Incentive Plan. Options granted under the 2002 Stock Incentive Plan may be Incentive Stock Options or Nonstatutory Stock Options under the applicable provisions of the Internal Revenue Code.

        Incentive Stock Options are granted only to employees of the Company. Incentive Stock Options granted to employees who own more than 10% of the total combined voting power of all classes of stock will be granted at no less than 110% of the fair market value of the Company's common stock on the date of grant. Nonstatutory Stock Options may be granted to employees, officers, directors, consultants and advisors. Incentive Stock Options generally vest either upon grant or ratably over four years. Nonstatutory Stock Options granted have varying vesting schedules. The options generally expire ten years after the date of grant.

        The following table summarizes all stock plan activity:

 
  Stock Options
 
  Shares
Outstanding

  Price
Per Share

  Weighted-Average
Exercise Price

Shares granted   19,114   $0.08   $ 0.08
   
         
Balance at December 31, 2001   19,114   0.08     0.08
  Shares granted   468,738   0.23     0.23
  Shares exercised   (3,754 ) 0.08     0.08
  Shares canceled   (51,200 ) 0.23     0.23
   
         
Balance at December 31, 2002   432,898   0.08-0.23     0.22
  Shares granted   621,156   0.23-0.60     0.34
  Shares exercised   (23,360 ) 0.08-0.23     0.22
   
         
Balance at December 31, 2003   1,030,694   $0.08-0.60   $ 0.29
   
         

        The following table summarizes information about options outstanding at December 31, 2003:

 
  Options Outstanding
   
   
 
  Options Exercisable
 
   
   
  Weighted-Average
Remaining
Contractual Life
(In years)

Range of Exercise
Prices

  Number of
Shares

  Weighted-Average
Exercise Price

  Number of
Shares

  Weighted Average
Exercise Price

$0.08   13,760   $ 0.08   8.0   5,124   $ 0.08
0.23-.2305   840,934     0.23   9.1   122,004     0.23
0.60   176,000     0.60   9.8       0.60
   
           
     
    1,030,694   $ 0.29   9.2   127,128   $ 0.22
   
           
     

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Stock-Based Compensation

        As discussed in Note 1, the Company applies APB 25 and related interpretations in accounting for stock options granted under the 2002 Plan. In Fiscal 2002 and 2003, the Company recorded $0.5 million and $2.0 million, respectively, in deferred compensation for employee stock options granted at exercise prices deemed to be below the fair value of common stock. In addition, in Fiscal 2002 the Company recorded $1.6 million in deferred compensation for restricted stock granted to employees at purchase prices deemed to be below the fair value of common stock.

        The Company amortizes the deferred stock-based compensation of employee options and restricted stock to compensation expense based on the straight-line method over the vesting periods of the applicable stock options and restricted stock, generally four years. Compensation expense of $0.4 million and $0.7 million for Fiscal 2002 and 2003, respectively, was recognized for employee options and restricted stock, net of forfeitures.

        As of December 31, 2003, the Company expects to record stock-based compensation expense of approximately $1.0 million, $1.0 million, and $0.7 million in the years ending December 31, 2004, 2005, and 2006, respectively, related to currently outstanding employee stock options and restricted stock.

Stock Options to Consultants

        As of December 31, 2003, the Company had granted options to purchase 63,401 shares of common stock to consultants, 6,400 of which were exercised, none of which were subject to repurchase, and 39,242 of which were unvested. These options were granted in exchange for consulting services to be rendered and vest over periods of up to four years. The Company recorded charges to operations for stock options granted to consultants using the graded-vesting method of $15,420, $36,385, $184,400 for Fiscal 2001, 2002 and 2003, respectively.

        The unvested shares held by consultants have been and will be revalued using the Company's estimate of fair value at each balance sheet date pursuant to EITF 96-18.

11. Income Taxes

        A reconciliation of federal statutory income tax provision to the Company's actual provision for Fiscal 2001, 2002 and 2003 is as follows:

 
  2001
  2002
  2003
 
Benefit at federal statutory tax rate   $ (126,151 ) $ (1,568,530 ) $ (2,701,432 )
Unbenefited operating losses     126,151     1,559,015     2,668,472  
Other         9,515     32,960  
   
 
 
 
Income tax provision   $   $   $  
   
 
 
 

F-23


        Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets are as follows:

 
  December 31,
 
 
  2002
  2003
 
Deferred tax assets:              
  Federal and state net operating losses   $ 1,804,294   $ 4,430,567  
  Research credits     99,286     253,599  
  Deferred compensation     168,962     525,625  
  Deferred revenue         227,160  
   
 
 
    Total deferred tax assets   $ 2,072,542   $ 5,436,951  
Deferred tax liabilities:              
  Depreciation     (31,430 )   (58,281 )
   
 
 
  Total deferred tax liabilities     (31,430 )   (58,281 )
  Valuation allowance     (2,041,112 )   (5,378,670 )
   
 
 
Net deferred tax assets   $   $  
   
 
 

        Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $1.8 million and $3.3 million for Fiscal 2002 and 2003, respectively.

        As of December 31, 2003, the Company had net operating loss carryforwards of $11.0 million to offset future federal and state taxable income. The Company also has federal and state research and development tax credits of approximately $178,000 and $115,000, respectively, as of December 31, 2003. The net operating loss carryforwards and federal research credits expire at various times through 2023.

        Utilization of the Company's net operating loss may be subject to substantial annual limitation due to the ownership change limitations provided by Internal Revenue Code (IRC) Sections 382 and 383 and similar state provisions. Such an annual limitation could result in the expiration of net operating losses and/or tax credits before utilization.

12. Net Loss and Unaudited Pro forma Net Loss Per Share

        The following tables set forth the computation of basic and diluted, and unaudited pro forma basic and diluted, net loss per share for the respective periods. The unaudited pro forma basic and diluted

F-24



net loss per share gives effect to the assumed conversion of the redeemable convertible preferred stock and the accrued dividends as if converted at the date of original issuance.

 
  2001
  2002
  2003
 
Basic and diluted:                    
Net loss   $ (371,033 ) $ (4,868,663 ) $ (7,945,389 )
Dividends and accretion to redemption value of redeemable convertible preferred stock     (21,917 )   (520,359 )   (1,898,126 )
   
 
 
 
Net loss attributable to common stockholders   $ (392,950 ) $ (5,389,022 ) $ (9,843,515 )
   
 
 
 
Shares used in computing basic and diluted net loss attributable to common stockholders per common share     58,280     946,013     1,961,281  
   
 
 
 
Basic and diluted net loss attributable to common stockholders per common share   $ (6.74 ) $ (5.70 ) $ (5.02 )
   
 
 
 
Unaudited pro forma basic and diluted:                    
Net loss               $ (7,945,389 )
               
 
Shares used in computing basic and diluted net loss attributable to common stockholders per share                 1,961,281  
Weighted average number of common shares assuming the conversion of all redeemable convertible preferred stock at the original date of issuance                 8,756,507  
               
 
Weighted average common shares used to compute unaudited pro forma net loss per share                 10,717,788  
               
 
Unaudited pro forma basic and diluted net loss per share               $ (0.92 )
               
 

F-25


 
  Three Months Ended
March 31,

 
 
  2003
  2004
 
Basic and diluted:              
Net loss   $ (1,497,563 ) $ (2,581,910 )
Deemed dividend related to beneficial conversion feature of Series C redeemable convertible preferred stock         (20,388,696 )
Dividends and accretion to redemption value of redeemable convertible preferred stock     (164,486 )   (817,523 )
   
 
 
Net loss attributable to common stockholders   $ (1,662,049 ) $ (23,788,129 )
   
 
 
Shares used in computing basic and diluted net loss attributable to common stockholders per common share     1,474,251     2,630,764  
   
 
 
Basic and diluted net loss attributable to common stockholders per common share   $ (1.13 ) $ (9.04 )
   
 
 
Unaudited pro forma basic and diluted:              
Net loss         $ (2,581,910 )
         
 
Shares used in computing basic and diluted net loss attributable to common stockholders per share           2,630,764  
Weighted average number of common shares assuming the conversion of all redeemable convertible preferred stock at the original date of issuance           12,919,665  
         
 
Weighted average common shares used to compute unaudited pro forma net loss per share           15,550,429  
         
 
Unaudited pro forma basic and diluted net loss per share         $ (1.53 )
         
 

13. Commitments and Contingencies

        The Company leases office space and equipment under various operating lease agreements. Rent expense under operating leases amounted to $0, $217,126 and $329,195 in Fiscal 2001, 2002 and 2003, respectively.

        At December 31, 2003, future minimum payments under noncancelable leases with terms of one year or more are as follows:

2004   $ 342,021
2005     3,135
2006     2,835
2007     473
   
Total minimum lease payments   $ 348,464
   

        We are engaged in discussions with a third party regarding the lease of new office and laboratory space which, if entered into, would significantly increase our annual lease commitments over the next

F-26



five years. Because we have not yet reached a definitive agreement, we are not currently able to estimate the expected increase.

        In connection with license arrangements signed during 2001 and 2002 with the research universities discussed in Note 3, the Company has certain annual fixed obligations to pay these institutions fees for the technology licensed. At December 31, 2003, financial obligations under these agreements are as follows:

2004   $ 67,500
2005     102,500
2006     102,500
2007     102,500
2008     127,500

        After 2008, the annual obligations, which extend indefinitely, range from $182,000 to $217,500 per year. The Company may terminate the agreements at any time without obligation for future payments. Annual payments may be applied towards royalties payable to the licensors for that year for product sales, sublicensing of the patent rights or joint development revenue.

        Companies that seek to market generic versions of branded products can be sued for infringing patents that purportedly cover such products and/or methods of using such products if the proposed marketing is to occur before such patents expire. Although the Company is not currently engaged in any actual or threatened material litigation, the Company believes that its product development plans will likely cause such litigation in the future. The accompanying financials do not include any provision or reserves for such potential litigation.

14. Line of Credit

        In December 2002, the Company entered into an equipment line of credit with Silicon Valley Bank, which provided for the Company to draw up to $1.2 million through March 31, 2003. Borrowings under the line bear interest at a rate between 5.0% and Prime plus 0.25% and are payable over a 36-month period from the cash drawn date. The line of credit includes a provision that any material adverse change in the Company or its business may be considered an event of default. There have been no events of default. As of December 31, 2003, the Company had drawn $1.0 million against the line of credit.

15. 401(k) Plan

        In 2003, the Company established a defined contribution 401(k) plan available to eligible employees. Employee contributions are voluntary and are determined on an individual basis, limited by the maximum amounts allowable under federal tax regulations. The Company has discretion to make contributions to the plan; however, to date no contributions have been made.

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16. Subsequent Events

Series C Issuance

        On February 27, 2004, the Company issued 2,612,696 shares of Series C Redeemable Convertible Preferred Stock, $0.01 par value per share, at a per share price of $7.8463, resulting in net proceeds to the Company of $20.4 million. These shares carry the same terms and conditions as disclosed in Note 7, and automatically convert to Common Stock upon the closing of an underwritten public offering of Common Stock. These shares contain a beneficial conversion feature based on the fair value of the Common Stock upon conversion. In accordance with EITF 98-5, Accounting for Convertible Securities with Beneficial Conversion Features or Contingently Adjustable Conversion Ratios, the value of such beneficial conversion feature, approximately $20.4 million, was recognized as a dividend in the first quarter of 2004.

Registration Statement

        On March 8, 2004, the Company's Board of Directors authorized the filing of a registration statement with the Securities and Exchange Commission in connection with the Company's proposed initial public offering. If the offering is completed upon the terms presently contemplated, all outstanding shares of convertible preferred stock will automatically convert into 15,014,390 shares of common stock upon completion of the proposed offering.

2004 Stock Incentive Plan

        The Company's 2004 Stock Incentive Plan (the Incentive Plan) was adopted by the Company's Board of Directors on March 8, 2004, subject to approval by the Company's stockholders. The Incentive Plan will become effective on the date that the registration statement, of which this prospectus forms a part, is declared effective. The Incentive Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards and other stock-based awards.

2004 Employee Stock Purchase Plan

        The Company's 2004 Employee Stock Purchase Plan (the Purchase Plan) was adopted by the Company's Board of Directors on March 8, 2004, subject to approval by the Company's stockholders. The Purchase Plan will become effective on the date that the registration statement, of which this prospectus forms a part, is declared effective. The Purchase Plan will allow employees to purchase stock at a price equal to 85% of the lower of the closing price of the Common Stock on the first day or the last day of each six-month offering period.

Incentive and Purchase Plans Authorization (Unaudited)

        On April 13, 2004, following approval of the Incentive Plan by the stockholders, the Board of Directors authorized the immediate issuance of up to 3,948,785 shares of common stock under the Incentive Plan with annual increases of the lowest of (i) 1,974,393 shares, (ii) 5% of the then outstanding number of common shares or (iii) such other amount as the Board of Directors may authorize through 2013. On the same date, following approval of the Purchase Plan by the stockholders, the Board of Directors authorized the immediate issuance of up to 524,652 shares of common stock under the Purchase Plan.

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17. Selected Quarterly Financial Data (Unaudited)

 
  Quarter Ended
 
 
  March 31
  June 30
  September 30
  December 31
 
2002                          
Net loss   $ (277,047 ) $ (1,250,937 ) $ (1,495,537 ) $ (1,845,142 )
Net loss attributable to common stockholders     (320,859 )   (1,398,656 )   (1,659,952 )   (2,009,555 )
Basic and diluted net loss per common share   $ (0.57 ) $ (1.61 ) $ (1.53 ) $ (1.60 )
Weighted average common shares used to compute net loss per share     565,870     869,282     1,083,290     1,256,513  

2003

 

 

 

 

 

 

 

 

 

 

 

 

 
Collaborative revenues               $ 1,454,287  
Net loss   $ (1,497,563 ) $ (1,801,414 ) $ (2,380,309 ) $ (2,266,103 )
Net loss attributable to common stockholders     (1,662,049 )   (2,143,069 )   (3,076,301 )   (2,962,096 )
Basic and diluted net loss per common share     (1.13 )   (1.14 )   (1.45 )   (1.25 )
Weighted average common shares used to compute net loss per share     1,474,251     1,881,094     2,116,966     2,361,354  

        Per common share amounts for the quarters and full years have been calculated separately. Accordingly, quarterly amounts do not add to the annual amount because of differences in the weighted average common shares outstanding during each period principally due to the effect of the Company's issuing shares of its common stock during the year.

        Diluted and basic net loss per common share are identical since common equivalent shares are excluded from the calculation, as their effect is anti-dilutive.

F-29


5,350,000 Shares

MOMENTA



SG Cowen & Co.

 

Banc of America Securities LLC

CIBC World Markets   ThinkEquity Partners LLC

Prospectus

                 , 2004

        Through and including                     , 2004 (the 25th day after the date of this prospectus), all dealers effecting transactions in these securities, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers' obligation to deliver a prospectus when acting as underwriters and with respect to their unsold allotments or subscriptions.




PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 13. Other Expenses of Issuance and Distribution.

        The following table indicates the expenses to be incurred in connection with the offering described in this Registration Statement, other than underwriting discounts and commissions, all of which will be paid by us. All amounts are estimated except the Securities and Exchange Commission registration fee and the National Association of Securities Dealers Inc. filing fee.

Securities and Exchange Commission registration fee   $ 10,928
National Association of Securities Dealers Inc. fee     9,125
NASDAQ Stock Market listing fee     100,000
Accountants' fees and expenses     350,000
Legal fees and expenses     750,000
Blue Sky fees and expenses     5,000
Transfer Agent's fees and expenses     5,000
Printing and engraving expenses     150,000
Miscellaneous     26,947
   
  Total   $ 1,407,000
   


Item 14. Indemnification of Directors and Officers.

        Section 102 of the General Corporation Law of the State of Delaware permits a corporation to eliminate the personal liability of directors of a corporation to the corporation or its stockholders for monetary damages for a breach of fiduciary duty as a director, except where the director breached his duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase in violation of Delaware corporate law or obtained an improper personal benefit. Our certificate of incorporation provides that no director shall be personally liable to us or our stockholders for monetary damages for any breach of fiduciary duty as a director, notwithstanding any provision of law imposing such liability, except to the extent that the General Corporation Law of the State of Delaware prohibits the elimination or limitation of liability of directors for breaches of fiduciary duty.

        Section 145 of the General Corporation Law of the State of Delaware provides that a corporation has the power to indemnify a director, officer, employee, or agent of the corporation and certain other persons serving at the request of the corporation in related capacities against expenses (including attorneys' fees), judgments, fines and amounts paid in settlements actually and reasonably incurred by the person in connection with an action, suit or proceeding to which he or she is or is threatened to be made a party by reason of such position, if such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation, and, in any criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful, except that, in the case of actions brought by or in the right of the corporation, no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or other adjudicating court determines that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.

II-1



        Our certificate of incorporation provides that we will indemnify each person who was or is a party or threatened to be made a party to any threatened, pending or completed action, suit or proceeding (other than an action by or in the right of us) by reason of the fact that he or she is or was, or has agreed to become, our director or officer, or is or was serving, or has agreed to serve, at our request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise (all such persons being referred to as an "Indemnitee"), or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding and any appeal therefrom, if such Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, our best interests, and, with respect to any criminal action or proceeding, he or she had no reasonable cause to believe his or her conduct was unlawful. Our certificate of incorporation provides that we will indemnify any Indemnitee who was or is a party to an action or suit by or in the right of us to procure a judgment in our favor by reason of the fact that the Indemnitee is or was, or has agreed to become, our director or officer, or is or was serving, or has agreed to serve, at our request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys' fees) and, to the extent permitted by law, amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding, and any appeal therefrom, if the Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, our best interests, except that no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to us, unless a court determines that, despite such adjudication but in view of all of the circumstances, he or she is entitled to indemnification of such expenses. Notwithstanding the foregoing, to the extent that any Indemnitee has been successful, on the merits or otherwise, he or she will be indemnified by us against all expenses (including attorneys' fees) actually and reasonably incurred in connection therewith. Expenses must be advanced to an Indemnitee under certain circumstances.


Item 15. Recent Sales of Unregistered Securities.

        Set forth below is information regarding shares of common stock and preferred stock issued, and options and warrants granted, by the Registrant within the past three years. Also included is the consideration, if any, received by the Registrant for such shares, options and warrants and information relating to the section of the Securities Act, or rule of the Securities and Exchange Commission, under which exemption from registration was claimed.

    (a)
    Issuances of Capital Stock.

    (1)
    In June 2001, in connection with the Registrant's formation, the Registrant issued and sold an aggregate of 2,680,002 shares of its restricted common stock at a price per share of $0.00008. These purchasers consisted of Robert S. Langer, Jr., Ram Sasisekharan, Ganesh Venkataraman, Alan L. Crane, Peter Barton Hutt, Lansing Brown Investments, LLC and Paul Schimmel.

    (2)
    In January 2002, the Registrant issued and sold 30,800 shares of its restricted common stock at a price per share of $0.0781 to Chi-Huey Wong. In August 2003, the Registrant repurchased 21,176 of these shares at a price per share of $0.0781. In March 2002, the Registrant issued and sold 980,858 shares of its restricted common stock at a price per share of $0.00008 to Alan L. Crane. In April 2002, the Registrant issued and sold 90,210 shares of its restricted common stock at a price per share of $0.1328 to Susan K. Whoriskey.

II-2


    (3)
    In August 2001, the Registrant issued and sold an aggregate of 250,000 shares of its Series A convertible preferred stock at a price per share of $1.00, together with warrants to purchase an aggregate of 585,926 shares of its Series A prime convertible preferred stock with an exercise price per share of $1.7067. Upon the closing of this offering, these shares will convert into 319,999 shares of common stock. These investors consisted of Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund III, L.P. and Robert M. Metcalfe. In January 2002, the warrant issued to Robert M. Metcalfe to purchase 46,874 shares of Series A prime convertible preferred stock was terminated.

    (4)
    In January 2002, the Registrant issued and sold an aggregate of 893,537 shares of its Series A prime convertible preferred stock at a price of $1.7067. Of these 893,537 shares of Series A prime convertible preferred stock, 539,052 shares were issued pursuant to the exercise of warrants issued to Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund III, L.P. in August 2001, at a price per share of $1.7067. Upon the closing of this offering, these shares will convert into 1,143,721 shares of common stock. These investors consisted of Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund III, L.P., Lansing Brown Investments, LLC, Alan L. Crane, Robert S. Langer, Jr., Peter Barton Hutt, Susan K. Whoriskey, BQ Ventures, LLC, The Paul Schimmel PS Plan and Wolf, Greenfield & Sacks Investment Trust, LLC.

    (5)
    In April 2002, the Registrant issued and sold an aggregate of 1,533,101 shares of its Series A double prime convertible preferred stock at a price per share of $2.87. Upon the closing of this offering, these shares will convert into 1,962,367 shares of common stock. These investors consisted of Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund III, L.P., CHP II, L.P., Lansing Brown Investments, LLC and James R. and Mary W. McNab Operating L.P.

    (6)
    In May 2003, the Registrant issued and sold an aggregate of 6,440,678 shares of its Series B convertible preferred stock at a price per share of $2.95. Upon the closing of this offering, these shares will convert into 8,244,062 shares of common stock. These investors consisted of Atlas Venture Fund V, L.P., Atlas Venture Parallel Fund, V-A, C.V., Atlas Venture Parallel Fund V-B, C.V., Atlas Venture Entrepreneurs' Fund V, L.P., Atlas Venture Fund VI, L.P., Atlas Venture Entrepreneurs' Fund VI, L.P., Atlas Venture Fund VI GmbH & Co. KG, MVM International Life Sciences Fund No. 1 L.P., MVM Limited, Stephen T. Reeders, David Brister, Paul Triniman, Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund, III, L.P. and CHP II, L.P.

    (7)
    In February 2004, the Registrant issued and sold an aggregate of 2,612,696 shares of its Series C convertible preferred stock at a price per share of $7.8463. Upon the closing of this offering, these shares will convert into 3,344,241 shares of common stock. These investors consisted of Mithra Ventures, L.P., Atlas Venture Fund V, L.P., Atlas Venture Parallel Fund, V-A, C.V., Atlas Venture Parallel Fund V-B, C.V., Atlas Venture Entrepreneurs' Fund V, L.P., Atlas Venture Fund VI, L.P., Atlas Venture Entrepreneurs' Fund VI, L.P., Atlas Venture Fund VI GmbH & Co. KG, MVM International Life Sciences Fund No. 1 L.P., MVM Limited, Stephen T. Reeders, David Brister, Paul Triniman, Martin Murphy, Richard Lim, Thomas Casdagli, Polaris Venture Partners III, L.P., Polaris Venture Partners Entrepreneurs' Fund III, L.P., Polaris Venture Partners Founders' Fund, III, L.P. and CHP II, L.P.

II-3


    (8)
    In December 2001 and April 2002, the Registrant issued an aggregate of 374,988 shares of its common stock to the Massachusetts Institute of Technology and certain individuals affiliated with the Massachusetts Institute of Technology in connection with a certain license agreement.

    (9)
    In December 2002, the Registrant issued a warrant to purchase an aggregate of 12,500 shares of its Series A double prime convertible preferred stock with an exercise price per share of $2.87 to Silicon Valley Bank. After this offering, the warrant issued to Silicon Valley Bank will be exercisable for 16,000 shares of common stock at an exercise price of $2.2422 per common share.

        No underwriters were involved in the foregoing sales of securities. We claimed exemption from registration under the Securities Act for the sales and issuances of securities in the transactions described in paragraphs (a)(1) through (a)(5), (a)(8) and (a)(9) above by virtue of Section 4(2) of the Securities Act in that such sales and issuances did not involve a public offering. The recipients of securities in each of these transactions represented their intention to acquire the securities for investment only and not with view to or for sale in connection with any distribution thereof and appropriate legends were affixed to the share certificates and instruments issued in such transactions. All recipients had adequate access, through their relationships with us, to information about us.

        We claimed exemption from registration under the Securities Act for the sales and issuances of securities in the transactions described in paragraphs (a)(6) and (a)(7) by virtue of Section 4(2) of the Securities Act and Rule 506 of Regulation D. Such sales and issuances did not involve any public offering, were made without general solicitation or advertising and each purchaser was a sophisticated investor with access to all relevant information necessary to evaluate the investment and represented to us that the shares were being acquired for investment.

    (b)
    Stock Option Grants.

        As of April 30, 2004, the Registrant had granted stock options under its stock incentive plan for an aggregate of 1,148,900 shares of common stock (net of exercises, expirations and cancellations) at a weighted average exercise price of $0.64 per share. Options to purchase 63,111 shares of common stock have been exercised for an aggregate purchase price of $13,738.63.

        The issuance of stock options and the common stock issuable upon the exercise of such options as described in this paragraph (b) of Item 15 were issued pursuant to written compensatory plans or arrangements with our employees, directors and consultants, in reliance on the exemption provided by Rule 701 promulgated under the Securities Act. All recipients either received adequate information about us or had access, through employment or other relationships, to such information.

        All of the foregoing securities are deemed restricted securities for purposes of the Securities Act. All certificates representing the issued shares of common stock described in this Item 15 included appropriate legends setting forth that the securities had not been registered and the applicable restrictions on transfer.

II-4




Item 16. Exhibits and Financial Statement Schedules.

    (a)
    Exhibits

Exhibit
No.

  Description
1.1   Form of Underwriting Agreement
3.1**   Second Amended and Restated Certificate of Incorporation
3.2**   Amended and Restated By-laws
3.3**   Form of Third Amended and Restated Certificate of Incorporation to be effective upon the closing of the offering
3.4**   Form of Second Amended and Restated By-laws to be effective upon the closing of the offering
4.1   Specimen Certificate evidencing shares of common stock
4.2**   Warrant to Purchase Stock, dated December 27, 2002, issued to Silicon Valley Bank; Acknowledgement and Agreement, dated February 25, 2004, by Silicon Valley Bancshares
4.3   Second Amended and Restated Investors' Rights Agreement, dated February 27, 2004, by and among the Purchasers listed therein, the Founders listed therein and the Registrant; Amendment No. 1 to Second Amended and Restated Investors' Rights Agreement, dated June 10, 2004, by and among the Registrant and the Investors set forth therein
5.1   Opinion of Wilmer Cutler Pickering Hale and Dorr LLP
10.1**   Amended and Restated 2002 Stock Incentive Plan
10.2**   2004 Stock Incentive Plan
10.3**   2004 Employee Stock Purchase Plan
10.4†**   Collaboration and License Agreement, dated November 1, 2003, by and among Biochemie West Indies, N.V., Geneva Pharmaceuticals, Inc. and the Registrant (this agreement is referred to in this Registration Statement as the collaboration and license agreement with Sandoz)
10.5†**   Amended and Restated Exclusive Patent License Agreement, dated November 1, 2002, by and between the Massachusetts Institute of Technology and the Registrant (the "November 1, 2002 M.I.T. License"); First Amendment to the November 1, 2002 M.I.T. License, dated November 15, 2002, by and between the Massachusetts Institute of Technology and the Registrant; Letter Agreement, dated September 12, 2003, between the Massachusetts Institute of Technology and the Registrant; Letter Agreement, dated October 22, 2003, between the Massachusetts Institute of Technology and the Registrant; Second Amendment to the November 1, 2002 M.I.T. License, dated November 19, 2003, by and between the Massachusetts Institute of Technology and the Registrant; Third Amendment to the November 1, 2002 M.I.T. License, dated April 2, 2004, by and between the Massachusetts Institute of Technology and the Registrant
10.6†**   Exclusive Patent License Agreement, dated October 31, 2002, by and between the Massachusetts Institute of Technology and the Registrant (the "October 31, 2002 M.I.T. License"); First Amendment to the October 31, 2002 M.I.T. License, dated November 15, 2002, by and between the Massachusetts Institute of Technology and the Registrant
10.7†**   License Agreement for Installing Novel Functional Groups for Therapeutics, dated November 20 2002, by and between The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory and the Registrant
10.8†   Development and Production Agreement for Active Pharmaceutical Ingredient, dated October 10, 2003, by and among Siegfried (USA), Inc., Siegfried Ltd. and the Registrant; Letter Agreement, dated February 14, 2004, by and between Siegfried (USA), Inc., Siegfried Ltd. and the Registrant; Letter Agreement, dated May 17, 2004, by and between Siegfried (USA), Inc., Siegfried Ltd. and the Registrant
     

II-5


10.9**   Employment Agreement, dated March 15, 2002, by and between Alan L. Crane and the Registrant
10.10**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Alan L. Crane and the Registrant
10.11**   Restricted Stock Purchase Agreement, dated March 15, 2002, by and between Alan L. Crane and the Registrant
10.12**   First Amended and Restated Employment Agreement, dated April 10, 2002, by and between Ganesh Venkataraman and the Registrant
10.13**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Ganesh Venkataraman and the Registrant
10.14**   Reallocation of Founder Shares Agreement, dated April 10, 2002, by and among Ganesh Venkataraman, Ram Sasisekharan, Robert S. Langer, Jr., Polaris Venture Partners III, L.P. and the Registrant
10.15**   Employment Agreement, dated April 10, 2002, by and between Susan Whoriskey and the Registrant
10.16**   Restricted Stock Purchase Agreement, dated April 10, 2002, by and between Susan Whoriskey and the Registrant
10.17**   Consulting Agreement, dated July 23, 2001, by and between Robert S. Langer, Jr. and the Registrant; Letter of Extension dated June 23, 2003
10.18**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Robert S. Langer, Jr. and the Registrant
10.19**   Consulting Agreement, dated August 16, 2001, by and between Ram Sasisekharan and the Registrant; Letter of Extension dated August 1, 2003
10.20**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Ram Sasisekharan and the Registrant
10.21**   Consulting Agreement, dated September 18, 2002, by and between Peter Barton Hutt and the Registrant; Letter of Extension dated September 29, 2003
10.22**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Peter Barton Hutt and the Registrant
10.23**   Loan and Security Agreement, dated December 27, 2002, by and between Silicon Valley Bank and the Registrant
10.24**   Sublease, dated February 25, 2002, by and between Curis, Inc. and the Registrant
10.25**   Commercial Lease Agreement (68 Moulton Street—3rd Floor), dated October 16, 2003, by and between 68 Moulton Street Realty Trust and the Registrant; Extension of Lease dated February 11, 2004
10.26**   Commercial Lease Agreement (68 Moulton Street—2nd Floor), dated February 1, 2004, by and between 68 Moulton Street Realty Trust and the Registrant
21.1**   Subsidiaries of the Registrant
23.1   Consent of Ernst & Young LLP
23.2   Consent of Wilmer Cutler Pickering Hale and Dorr LLP (included in Exhibit 5.1)
24.1**   Power of Attorney (see page II-9)

*
To be filed by amendment.

**
Previously filed.

Confidential treatment requested as to certain portions, which portions have been filed separately with the Securities and Exchange Commission.

(b)
Financial Statement Schedules.

        None

II-6



Item 17. Undertakings.

        The undersigned registrant hereby undertakes to provide to the underwriters at the closing specified in the underwriting agreement, certificates in such denominations and registered in such names as required by the underwriters to permit prompt delivery to each purchaser.

        Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that, in the opinion of the Securities and Exchange Commission, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

      The undersigned registrant hereby undertakes that:

      (1)
      For purposes of determining any liability under the Securities Act, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in the form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part of the registration statement as of the time it was declared effective.

      (2)
      For purposes of determining any liability under the Securities Act, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

II-7



SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this Amendment No. 4 to Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts on this 15th day of June, 2004.

    MOMENTA PHARMACEUTICALS, INC.

 

 

By:

/s/  
ALAN L. CRANE       
Alan L. Crane
Chairman, President and Chief Executive Officer

II-8



SIGNATURES AND POWER OF ATTORNEY

        Pursuant to the requirements of the Securities Act of 1933, this Amendment No. 4 to Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

Signature
  Title
  Date

 

 

 

 

 
/s/   ALAN L. CRANE       
Alan L. Crane
  Chairman, President, Chief Executive Officer and Director (Principal Executive Officer)   June 15, 2004

/s/  
RICHARD P. SHEA       
Richard P. Shea

 

Chief Financial Officer (Principal Financial and Accounting Officer)

 

June 15, 2004

*

Peter Barrett, Ph.D.

 

Director

 

June 15, 2004

*

John K. Clarke

 

Director

 

June 15, 2004

*

Peter Barton Hutt, LL.B., LL.M.

 

Director

 

June 15, 2004

*

Robert S. Langer, Jr., Sc.D.

 

Director

 

June 15, 2004

*

Stephen T. Reeders, D.M., MRCP

 

Director

 

June 15, 2004

*

Ram Sasisekharan, Ph.D.

 

Director

 

June 15, 2004

*

Bennett M. Shapiro, M.D.

 

Director

 

June 15, 2004

*

Christoph H. Westphal, M.D., Ph.D.

 

Director

 

June 15, 2004

*

John L. Zabriskie, Ph.D.

 

Director

 

June 15, 2004

        By the signature set forth below, the undersigned, pursuant to the duly authorized powers of attorney filed with the Securities and Exchange Commission, has signed this Amendment No. 4 to Registration Statement on behalf of the person indicated.

* By:   /s/   ALAN L. CRANE       
Alan L. Crane
Attorney-in-Fact
   

II-9



EXHIBIT INDEX

Exhibit
No.

  Description
1.1   Form of Underwriting Agreement
3.1**   Second Amended and Restated Certificate of Incorporation
3.2**   Amended and Restated By-laws
3.3**   Form of Third Amended and Restated Certificate of Incorporation to be effective upon the closing of the offering
3.4**   Form of Second Amended and Restated By-laws to be effective upon the closing of the offering
4.1   Specimen Certificate evidencing shares of common stock
4.2**   Warrant to Purchase Stock, dated December 27, 2002, issued to Silicon Valley Bank; Acknowledgement and Agreement, dated February 25, 2004, by Silicon Valley Bancshares
4.3   Second Amended and Restated Investors' Rights Agreement, dated February 27, 2004, by and among the Purchasers listed therein, the Founders listed therein and the Registrant; Amendment No. 1 to Second Amended and Restated Investors' Rights Agreement dated June 10, 2004, by and among the Registrant and the Investors set forth therein
5.1   Opinion of Wilmer Cutler Pickering Hale and Dorr LLP
10.1**   Amended and Restated 2002 Stock Incentive Plan
10.2**   2004 Stock Incentive Plan
10.3**   2004 Employee Stock Purchase Plan
10.4†**   Collaboration and License Agreement, dated November 1, 2003, by and among Biochemie West Indies, N.V., Geneva Pharmaceuticals, Inc. and the Registrant (this agreement is referred to in this Registration Statement as the collaboration and license agreement with Sandoz)
10.5†**   Amended and Restated Exclusive Patent License Agreement, dated November 1, 2002, by and between the Massachusetts Institute of Technology and the Registrant (the "November 1, 2002 M.I.T. License"); First Amendment to the November 1, 2002 M.I.T. License, dated November 15, 2002, by and between the Massachusetts Institute of Technology and the Registrant; Letter Agreement, dated September 12, 2003, between the Massachusetts Institute of Technology and the Registrant; Letter Agreement, dated October 22, 2003, between the Massachusetts Institute of Technology and the Registrant; Second Amendment to the November 1, 2002 M.I.T. License, dated November 19, 2003, by and between the Massachusetts Institute of Technology and the Registrant; Third Amendment to the November 1, 2002 M.I.T. License, dated April 2, 2004, by and between the Massachusetts Institute of Technology and the Registrant
10.6†**   Exclusive Patent License Agreement, dated October 31, 2002, by and between the Massachusetts Institute of Technology and the Registrant (the "October 31, 2002 M.I.T. License"); First Amendment to the October 31, 2002 M.I.T. License, dated November 15, 2002, by and between the Massachusetts Institute of Technology and the Registrant
10.7†**   License Agreement for Installing Novel Functional Groups for Therapeutics, dated November 20 2002, by and between The Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory and the Registrant
10.8†   Development and Production Agreement for Active Pharmaceutical Ingredient, dated October 10, 2003, by and among Siegfried (USA), Inc., Siegfried Ltd. and the Registrant; Letter Agreement, dated February 14, 2004, by and between Siegfried (USA), Inc., Siegfried Ltd. and the Registrant; Letter Agreement, dated May 17, 2004, by and between Siegfried (USA), Inc., Siegfried Ltd. and the Registrant
10.9**   Employment Agreement, dated March 15, 2002, by and between Alan L. Crane and the Registrant
     

II-10


10.10**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Alan L. Crane and the Registrant
10.11**   Restricted Stock Purchase Agreement, dated March 15, 2002, by and between Alan L. Crane and the Registrant
10.12**   First Amended and Restated Employment Agreement, dated April 10, 2002, by and between Ganesh Venkataraman and the Registrant
10.13**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Ganesh Venkataraman and the Registrant
10.14**   Reallocation of Founder Shares Agreement, dated April 10, 2002, by and among Ganesh Venkataraman, Ram Sasisekharan, Robert S. Langer, Jr., Polaris Venture Partners III, L.P. and the Registrant
10.15**   Employment Agreement, dated April 10, 2002, by and between Susan Whoriskey and the Registrant
10.16**   Restricted Stock Purchase Agreement, dated April 10, 2002, by and between Susan Whoriskey and the Registrant
10.17**   Consulting Agreement, dated July 23, 2001, by and between Robert S. Langer, Jr. and the Registrant; Letter of Extension dated June 23, 2003
10.18**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Robert S. Langer, Jr. and the Registrant
10.19**   Consulting Agreement, dated August 16, 2001, by and between Ram Sasisekharan and the Registrant; Letter of Extension dated August 1, 2003
10.20**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Ram Sasisekharan and the Registrant
10.21**   Consulting Agreement, dated September 18, 2002, by and between Peter Barton Hutt and the Registrant; Letter of Extension dated September 29, 2003
10.22**   Restricted Stock Purchase Agreement, dated June 13, 2001, by and between Peter Barton Hutt and the Registrant
10.23**   Loan and Security Agreement, dated December 27, 2002, by and between Silicon Valley Bank and the Registrant
10.24**   Sublease, dated February 25, 2002, by and between Curis, Inc. and the Registrant
10.25**   Commercial Lease Agreement (68 Moulton Street—3rd Floor), dated October 16, 2003, by and between 68 Moulton Street Realty Trust and the Registrant; Extension of Lease dated February 11, 2004
10.26**   Commercial Lease Agreement (68 Moulton Street—2nd Floor), dated February 1, 2004, by and between 68 Moulton Street Realty Trust and the Registrant
21.1**   Subsidiaries of the Registrant
23.1   Consent of Ernst & Young LLP
23.2   Consent of Wilmer Cutler Pickering Hale and Dorr LLP (included in Exhibit 5.1)
24.1**   Power of Attorney (see page II-9)

*
To be filed by amendment.

**
Previously filed.

Confidential treatment requested as to certain portions, which portions have been filed separately with the Securities and Exchange Commission.

II-11



EXHIBIT 1.1

MOMENTA PHARMACEUTICALS, INC.

[___] Shares

Common Stock

UNDERWRITING AGREEMENT

dated [___], 2004

SG COWEN & CO., LLC
BANC OF AMERICA SECURITIES LLC
CIBC WORLD MARKETS CORP.
THINKEQUITY PARTNERS LLC


TABLE OF CONTENTS

                                                                                                                PAGE
Section 1.     Representations and Warranties of the Company......................................................2

      (a)   COMPLIANCE WITH REGISTRATION REQUIREMENTS.............................................................2
      (b)   OFFERING MATERIALS FURNISHED TO UNDERWRITERS..........................................................3
      (c)   DISTRIBUTION OF OFFERING MATERIAL BY THE COMPANY......................................................3
      (d)   THE UNDERWRITING AGREEMENT............................................................................3
      (e)   AUTHORIZATION OF THE COMMON SHARES....................................................................3
      (f)   NO APPLICABLE REGISTRATION OR OTHER SIMILAR RIGHTS....................................................3
      (g)   NO MATERIAL ADVERSE CHANGE............................................................................3
      (h)   INDEPENDENT ACCOUNTANTS...............................................................................4
      (i)   PREPARATION OF THE FINANCIAL STATEMENTS...............................................................4
      (j)   INCORPORATION AND GOOD STANDING OF THE COMPANY........................................................4
      (k)   CAPITALIZATION AND OTHER CAPITAL STOCK MATTERS........................................................4
      (l)   QUOTATION.............................................................................................5
      (m)   NON-CONTRAVENTION OF EXISTING INSTRUMENTS; NO FURTHER AUTHORIZATIONS OR APPROVALS REQUIRED............5
      (n)   NO MATERIAL ACTIONS OR PROCEEDINGS....................................................................5
      (o)   INTELLECTUAL PROPERTY.................................................................................6
      (p)   ALL NECESSARY PERMITS, ETC............................................................................6
      (q)   TITLE TO PROPERTIES...................................................................................6
      (r)   TAX LAW COMPLIANCE....................................................................................7
      (s)   COMPANY NOT AN "INVESTMENT COMPANY"...................................................................7
      (t)   INSURANCE.............................................................................................7
      (u)   NO PRICE STABILIZATION OR MANIPULATION................................................................7
      (v)   RELATED PARTY TRANSACTIONS............................................................................7
      (w)   DISCLOSURE CONTROLS AND PROCEDURES....................................................................8
      (x)   NO UNLAWFUL CONTRIBUTIONS OR OTHER PAYMENTS...........................................................8
      (y)   COMPANY'S ACCOUNTING SYSTEM...........................................................................8
      (z)   COMPLIANCE WITH ENVIRONMENTAL LAWS....................................................................8
      (aa)  ERISA COMPLIANCE......................................................................................9
      (bb)  BROKERS..............................................................................................10
      (cc)  NO OUTSTANDING LOANS OR OTHER INDEBTEDNESS...........................................................10
      (dd)  COMPLIANCE WITH LAWS.................................................................................10
      (ee)  DIRECTED SHARE PROGRAM...............................................................................10
      (ff)  NO LABOR DISPUTES....................................................................................11
      (gg)  MATERIAL CONTRACTS...................................................................................11
      (hh)  NO MARGIN SECURITIES.................................................................................11
      (ii)  FORWARD-LOOKING STATEMENTS...........................................................................11
      (jj)  SARBANES-OXLEY ACT OF 2002...........................................................................11
      (kk)  CORPORATE GOVERNANCE.................................................................................11
      (ll)  COMMUNICATION WITH THE FDA...........................................................................11
      (mm)  STUDIES AND OTHER PRECLINICAL TESTS..................................................................12

Section 2.     PURCHASE, SALE AND DELIVERY OF THE COMMON SHARES..................................................12

      (a)   THE FIRM COMMON SHARES...............................................................................12
      (b)   THE FIRST CLOSING DATE...............................................................................12
      (c)   THE OPTIONAL COMMON SHARES; THE SECOND CLOSING DATE..................................................12
      (d)   PUBLIC OFFERING OF THE COMMON SHARES.................................................................13
      (e)   PAYMENT FOR THE COMMON SHARES........................................................................13
      (f)   DELIVERY OF THE COMMON SHARES........................................................................13

                                       i

Section 3.     ADDITIONAL COVENANTS OF THE COMPANY...............................................................14

      (a)   REPRESENTATIVES' REVIEW OF PROPOSED AMENDMENTS AND SUPPLEMENTS.......................................14
      (b)   SECURITIES ACT COMPLIANCE............................................................................14
      (c)   AMENDMENTS AND SUPPLEMENTS TO THE PROSPECTUS AND OTHER SECURITIES ACT MATTERS........................14
      (d)   COPIES OF ANY AMENDMENTS AND SUPPLEMENTS TO THE PROSPECTUS...........................................15
      (e)   BLUE SKY COMPLIANCE..................................................................................15
      (f)   USE OF PROCEEDS......................................................................................15
      (g)   TRANSFER AGENT.......................................................................................15
      (h)   EARNINGS STATEMENT...................................................................................15
      (i)   PERIODIC REPORTING OBLIGATIONS.......................................................................16
      (j)   DIRECTED SHARE PROGRAM...............................................................................16
      (k)   QUOTATION............................................................................................16
      (l)   AGREEMENT NOT TO OFFER OR SELL ADDITIONAL SECURITIES.................................................16
      (m)   INVESTMENT LIMITATION................................................................................16
      (n)   NO MANIPULATION OF PRICE.............................................................................16
      (o)   EXISTING LOCK-UP AGREEMENT...........................................................................17
      (p)   NO PRESS RELEASES OR CONFERENCES.....................................................................17
      (q)   NO ACTIVE TRADING IN OR RAISING THE PRICE OF THE COMMON SHARES.......................................17

Section 4.     PAYMENT OF EXPENSES...............................................................................17

Section 5.     CONDITIONS OF THE OBLIGATIONS OF THE UNDERWRITERS.................................................18

      (a)   ACCOUNTANTS' COMFORT LETTER..........................................................................18
      (b)   COMPLIANCE WITH REGISTRATION REQUIREMENTS; NO STOP ORDER; NO OBJECTION FROM NASD.....................18
      (c)   NO MATERIAL ADVERSE CHANGE OR RATINGS AGENCY CHANGE..................................................19
      (d)   OPINION OF COUNSEL FOR THE COMPANY...................................................................19
      (e)   OPINION OF COUNSEL FOR THE COMPANY WITH RESPECT TO INTELLECTUAL PROPERTY MATTERS.....................19
      (f)   OPINION OF COUNSEL FOR THE UNDERWRITERS..............................................................19
      (g)   OFFICERS' CERTIFICATE................................................................................19
      (h)   BRING-DOWN COMFORT LETTER............................................................................20
      (i)   LOCK-UP AGREEMENT FROM CERTAIN SECURITY HOLDERS OF THE COMPANY.......................................20
      (j)   NOTICE OF A DISCLOSURE VIOLATION.....................................................................20
      (k)   AUTHORIZATION OF THIS AGREEMENT AND RELATED TRANSACTIONS.............................................20
      (l)   NO GOVERNMENT PROHIBITIONS...........................................................................21
      (m)   INCLUSION ON THE NASDAQ NATIONAL MARKET..............................................................21
      (n)   AMENDMENT OF SECOND AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT.................................21
      (o)   ADDITIONAL DOCUMENTS.................................................................................21

Section 6.     REIMBURSEMENT OF UNDERWRITERS' EXPENSES...........................................................21

Section 7.     EFFECTIVENESS OF THIS AGREEMENT...................................................................22

Section 8.     INDEMNIFICATION...................................................................................22

      (a)   INDEMNIFICATION OF THE UNDERWRITERS..................................................................22
      (b)   INDEMNIFICATION OF THE COMPANY, ITS DIRECTORS AND OFFICERS...........................................23
      (c)   NOTIFICATIONS AND OTHER INDEMNIFICATION PROCEDURES...................................................24
      (d)   SETTLEMENTS..........................................................................................24
      (e)   INDEMNIFICATION FOR DIRECTED SHARES..................................................................25

                                       ii

Section 9.  CONTRIBUTION......................................................................................25

Section 10. DEFAULT OF ONE OR MORE OF THE SEVERAL UNDERWRITERS................................................26

Section 11. TERMINATION OF THIS AGREEMENT.....................................................................27

Section 12. REPRESENTATIONS AND INDEMNITIES TO SURVIVE DELIVERY...............................................28

Section 13. NOTICES...........................................................................................28

Section 14. SUCCESSORS........................................................................................29

Section 15. PARTIAL UNENFORCEABILITY..........................................................................29

Section 16. GOVERNING LAW PROVISIONS..........................................................................30

      (a)   CONSENT TO JURISDICTION...........................................................................30
      (b)   WAIVER OF IMMUNITY................................................................................30

Section 17.    GENERAL PROVISIONS.............................................................................30

iii

UNDERWRITING AGREEMENT

[________ __], 2004

SG COWEN & CO., LLC
BANC OF AMERICA SECURITIES LLC
CIBC WORLD MARKETS CORP.
THINKEQUITY PARTNERS LLC
As Representatives of the several Underwriters
c/o BANC OF AMERICA SECURITIES LLC
9 West 57th Street
New York, NY 10019

Ladies and Gentlemen:

INTRODUCTORY. Momenta Pharmaceuticals, Inc., a Delaware corporation (the "Company), proposes to issue and sell to the several underwriters named in Schedule A (the "Underwriters") an aggregate of [___] shares (the "Firm Common Shares") of its Common Stock, par value $0.0001 per share (the "Common Stock"). In addition, the Company has granted to the Underwriters an option to purchase up to an additional [___] shares (the "Optional Common Shares") of Common Stock, as provided in Section 2. The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are collectively called the "Common Shares". SG Cowen & Co., LLC ("SG Cowen"), Banc of America Securities LLC ("BAS"), CIBC World Markets Corp. and ThinkEquity Partners LLC have agreed to act as representatives of the several Underwriters (in such capacity, the "Representatives") in connection with the offering and sale of the Common Shares.

The Company and the Underwriters agree that up to [___] of the Firm Common Shares to be purchased by the Underwriters (the "Directed Shares") shall be reserved for sale by the Underwriters to certain eligible directors, officers and employees of the Company and persons having business relationships with the Company (collectively, the "Participants"), as part of the distribution of the Common Shares by the Underwriters (the "Directed Share Program") subject to the terms of this Agreement, the applicable rules, regulations and interpretations of the National Association of Securities Dealers, Inc. (the "NASD") and all other applicable laws, rules and regulations. BAS (the "Designated Underwriter") shall process the sales to the Participants under the Directed Share Program. To the extent that such Directed Shares are not orally confirmed for purchase by the Participants by the end of the first business day after the date of this Agreement, such Directed Shares may be offered to the public as part of the public offering contemplated hereby.

The Company has prepared and filed with the Securities and Exchange Commission (the "Commission") a registration statement on Form S-1 (File No. 333-113522), which contains a form of prospectus to be used in connection with the public offering and sale of the Common Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it was declared effective by the Commission under the

1

Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the "Securities Act"), including any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or Rule 434 under the Securities Act, is called the "Registration Statement". Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act is called the "Rule 462(b) Registration Statement", and from and after the date and time of filing of the Rule 462(b) Registration Statement the term "Registration Statement" shall include the Rule 462(b) Registration Statement. Such prospectus, in the form first used by the Underwriters to confirm sales of the Common Shares, is called the "Prospectus"; provided, however, if the Company has, with the consent of SG Cowen and BAS, jointly, elected to rely upon Rule 434 under the Securities Act, the term "Prospectus" shall mean the Company's prospectus subject to completion (each, a "preliminary prospectus") dated May 21, 2004 (such preliminary prospectus is called the "Rule 434 preliminary prospectus"), together with the applicable term sheet (the "Term Sheet") prepared and filed by the Company with the Commission under Rules 434 and 424(b) under the Securities Act, and all references in this Agreement to the date of the Prospectus shall mean the date of the Term Sheet. All references in this Agreement to the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus, the Prospectus or the Term Sheet, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System ("EDGAR").

The Company hereby confirms its agreements with the Underwriters as follows:

Section 1. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company hereby represents, warrants and covenants to each Underwriter as follows:

(a) COMPLIANCE WITH REGISTRATION REQUIREMENTS. The Registration Statement and any Rule 462(b) Registration Statement have been declared effective by the Commission under the Securities Act. The Company has complied to the Commission's satisfaction with all requests of the Commission for additional or supplemental information. No stop order suspending the effectiveness of the Registration Statement or any Rule 462(b) Registration Statement is in effect and no proceedings for such purpose have been instituted or, to the best knowledge of the Company, are pending, contemplated or threatened by the Commission.

Each preliminary prospectus and the Prospectus when filed complied in all material respects with the Securities Act and (except as may be permitted by Regulation S-T under the Securities Act if filed by electronic transmission pursuant to EDGAR) was identical to the copy thereof delivered to the Underwriters for use in connection with the offer and sale of the Common Shares. Each of the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendment thereto, at the time it became effective, complied in all material respects with the Securities Act and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading. The Prospectus (including any Prospectus wrapper), as amended or supplemented, as of its date and as of the First Closing Date, as defined in
Section 2(b) (and if Optional Common Shares are to be purchased, the Second Closing Date (as defined in Section 2(c)), did not and will not contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The representations and warranties

2

set forth in the two immediately preceding sentences do not apply to statements in or omissions from the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment thereto, or the Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by the Representatives expressly for use therein. There are no contracts or other documents required to be described in the Prospectus or to be filed as exhibits to the Registration Statement which have not been described or filed as required.

(b) OFFERING MATERIALS FURNISHED TO UNDERWRITERS. The Company has delivered to each of SG Cowen and BAS one complete manually signed copy of the Registration Statement and of each consent and certificate of experts filed as a part thereof, and conformed copies of the Registration Statement (without exhibits) and preliminary prospectuses and the Prospectus, as amended or supplemented, in such quantities and at such places as the Representatives have reasonably requested for each of the Underwriters.

(c) DISTRIBUTION OF OFFERING MATERIAL BY THE COMPANY. The Company has not distributed and will not distribute, prior to the later of the Second Closing Date and the completion of the Underwriters' distribution of the Common Shares, any offering material in connection with the offering and sale of the Common Shares other than a preliminary prospectus, the Prospectus or the Registration Statement.

(d) THE UNDERWRITING AGREEMENT. This Agreement has been duly authorized, executed and delivered by the Company.

(e) AUTHORIZATION OF THE COMMON SHARES. The Common Shares to be purchased by the Underwriters from the Company have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered by the Company pursuant to this Agreement against payment of the consideration set forth herein, will be validly issued, fully paid and nonassessable and free of any preemptive rights, rights of first refusal or similar rights and will conform to the description thereof contained in the Prospectus.

(f) NO APPLICABLE REGISTRATION OR OTHER SIMILAR RIGHTS. There are no persons with registration or other similar rights to have any equity or debt securities registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived.

(g) NO MATERIAL ADVERSE CHANGE. Except as otherwise disclosed in the Prospectus, subsequent to the respective dates as of which information is given in the Prospectus: (i) there has been no material adverse change, or any development that could reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the earnings, business or operations, whether or not arising from transactions in the ordinary course of business, of the Company (any such change is called a "Material Adverse Change"); (ii) the Company has not incurred any material liability or obligation, indirect, direct or contingent, not in the ordinary course of business, nor entered into any material transaction or agreement not in the ordinary course of business; and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company on any capital stock, or, except for repurchases by the

3

Company of Common Stock pursuant to restricted stock purchase agreements in effect as of the date of the Prospectus, repurchase or redemption by the Company of any capital stock.

(h) INDEPENDENT ACCOUNTANTS. Ernst & Young LLP, who have expressed their opinion with respect to the financial statements (which term as used in this Agreement includes the related notes thereto) filed with the Commission as a part of the Registration Statement and included in the Prospectus, are independent public or certified public accountants as required by the Securities Act.

(i) PREPARATION OF THE FINANCIAL STATEMENTS. The financial statements filed with the Commission as a part of the Registration Statement and included in the Prospectus present fairly in all material respects the consolidated financial position of the Company as of and at the dates indicated and the results of its operations and cash flows for the periods specified. Such financial statements have been prepared in conformity with generally accepted accounting principles employed in the United States, applied on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. No other financial statements or supporting schedules are required to be included in the Registration Statement. The financial data set forth in the Prospectus under the captions "Summary--Summary Financial and Operating Data", "Capitalization" and "Selected Financial and Operating Data" fairly present in all material respects the information set forth therein on a basis consistent with that of the audited financial statements contained in the Registration Statement. The pro forma financial statements of the Company and the related notes thereto included under the caption "Summary--Summary Financial and Operating Data", "Capitalization", "Selected Financial and Operating Data" and elsewhere in the Prospectus and in the Registration Statement present fairly the information contained therein and the adjustments used therein are appropriate to give effect to the transactions and circumstances referred to therein.

(j) INCORPORATION AND GOOD STANDING OF THE COMPANY. The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation and has full corporate power and authority to own, lease and operate its properties and to conduct its business as described in the Prospectus and to enter into and perform its obligations under this Agreement. The Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except for such jurisdictions where the failure to so qualify or to be in good standing would not, individually or in the aggregate, result in a Material Adverse Change. The Company does not own or control, directly or indirectly, any interest in any corporation, association or other entity.

(k) CAPITALIZATION AND OTHER CAPITAL STOCK MATTERS. The authorized, issued and outstanding capital stock of the Company is as set forth in the Prospectus under the caption "Capitalization" (other than for subsequent issuances, if any, pursuant to employee benefit plans described in the Prospectus or upon exercise of outstanding options or warrants described in the Prospectus). The Common Stock (including the Common Shares) conforms in all material respects to the description thereof contained in the Prospectus. All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid and nonassessable and have been issued in compliance with federal and state securities laws. None

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of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company. There are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company other than those described in the Prospectus or issued or granted in the ordinary course of the Company's business after the date of the Prospectus under the Company's stock incentive or stock purchase plans. The description of the Company's stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, set forth in the Prospectus fairly presents in all material respects the information required to be shown with respect to such plans, arrangements, options and rights.

(l) QUOTATION. The Common Shares have been approved for inclusion on the Nasdaq National Market, subject only to official notice of issuance.

(m) NON-CONTRAVENTION OF EXISTING INSTRUMENTS; NO FURTHER AUTHORIZATIONS OR APPROVALS REQUIRED. The Company is not in violation of its charter or by-laws nor is it in default (or, with the giving of notice or lapse of time, would it be in default) ("Default") under any indenture, mortgage, loan or credit agreement, note, contract, franchise, lease or other instrument to which the Company is a party or by which it may be bound (including, without limitation, the Loan and Security Agreement, dated as of December 27, 2002, by and between the Company and Silicon Valley Bank (doing business as Silicon Valley East)), or to which any of the property or assets of the Company is subject (each, an "Existing Instrument"), except for such Defaults as would not reasonably be expected to result in a Material Adverse Change. The Company's execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby and by the Prospectus (i) have been duly authorized by all necessary corporate action and will not result in any violation of the provisions of the charter or by-laws of the Company, (ii) will not conflict with or constitute a breach of, or Default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company pursuant to, or require the consent of any other party to, any Existing Instrument, except as would not reasonably be expected to result in a Material Adverse Change and (iii) will not result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company, except as would not reasonably be expected to result in a Material Adverse Change. No consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency, is required for the Company's execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby and by the Prospectus, except such as have been obtained or made by the Company and are in full force and effect under the Securities Act, applicable state securities or blue sky laws and from the NASD.

(n) NO MATERIAL ACTIONS OR PROCEEDINGS. Except as described in the Registration Statement and Prospectus, there are no legal or governmental actions, suits or proceedings pending or, to the Company's knowledge, threatened
(i) against the Company, (ii) which have as the subject thereof any officer or director of, or property owned or leased by, the Company or (iii) relating to environmental or discrimination matters, where in any such case (A) there is a reasonable possibility that such action, suit or proceeding might be determined adversely to the Company and (B) any such action, suit or proceeding, if so determined adversely, would

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reasonably be expected to result in a Material Adverse Change or adversely affect the consummation of the transactions contemplated by this Agreement. No material labor dispute with the employees of the Company, or with the employees of any principal supplier of the Company, exists or, to the Company's knowledge, is threatened or imminent that could reasonably be expected to result in a Material Adverse Change.

(o) INTELLECTUAL PROPERTY. Except as described in the Registration Statement and Prospectus, the Company owns, or has obtained valid and enforceable licenses for, or other rights to use, the inventions, patent applications, patents, trademarks (both registered and unregistered), trade names, copyrights and trade secrets described in the Registration Statement and Prospectus as being owned or licensed by it, which the Company reasonably believes are necessary for the conduct of its business (collectively, "Intellectual Property"). Except as described in the Registration Statement and Prospectus, (i) the Company believes that there are no third parties who have rights to any Intellectual Property, except for the ownership rights of the owners of the Intellectual Property which is licensed to the Company; (ii) to the Company's knowledge, there is no infringement by third parties of any Intellectual Property; (iii) there is no pending or, to the Company's knowledge, threatened action, suit, proceeding or claim by others challenging the Company's rights in or to any Intellectual Property, and the Company is unaware of any facts which it believes would form a reasonable basis for any such claim; (iv) there is no pending or, to the Company's knowledge, threatened action, suit, proceeding or claim by others challenging the validity or scope of any Intellectual Property, and the Company is unaware of any facts which it believes would form a reasonable basis for any such claim; (v) there is no pending or, to the Company's knowledge, threatened action, suit, proceeding or claim by others that the Company infringes or otherwise violates any patent, trademark, trade name, copyright, trade secret or other proprietary rights of others, and the Company does not know of any such infringement or violation; (vi) to the Company's knowledge, there is no patent or patent application which contains claims that interfere with the issued or pending claims of any of the Intellectual Property; and (vii) the Company, the inventors of the Intellectual Property, and, to the Company's knowledge, the Company's licensors, have complied with the duty of candor and disclosure set forth in 37 C.F.R. ss. 1.56 with respect to each of the patents and patent applications comprising the Intellectual Property. None of the technology employed by the Company has been obtained or is being used by the Company in violation of any contractual obligation binding on the Company or, to the Company's knowledge, any of its officers, directors or employees in violation of the rights of any persons.

(p) ALL NECESSARY PERMITS, ETC. The Company possesses such valid and current licenses, certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory agencies or bodies necessary to conduct its business (other than any the absence of which would not reasonably be expected to result in a Material Adverse Change), and the Company has not received any notice of proceedings relating to the revocation or modification of, or non-compliance with, any such licenses, certificates, authorizations or permits which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, could reasonably be expected to result in a Material Adverse Change.

(q) TITLE TO PROPERTIES. The Company has good and marketable title to all the properties and assets reflected as owned in the financial statements referred to in Section 1(i) above, in each case free and clear of any security interests, mortgages, liens, encumbrances,

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equities, claims and other defects, except such as do not materially and adversely affect the value of such properties or assets and do not materially interfere with the use made of such properties or assets by the Company. The real property, improvements, equipment and personal property held under lease by the Company are held under valid and enforceable leases, with such exceptions as are not material and do not materially interfere with the use made of such real property, improvements, equipment or personal property by the Company.

(r) TAX LAW COMPLIANCE. The Company has timely filed all necessary federal, state and foreign income and franchise tax returns and has timely paid all taxes required to be paid by it and, if due and payable, any related or similar assessment, fine or penalty levied against it. The Company has made adequate charges, accruals and reserves in the applicable financial statements referred to in Section 1(i) above in respect of all federal, state and foreign income and franchise taxes for all periods as to which the tax liability of the Company has not been finally determined. The Company does not have any tax deficiency or claims outstanding or assessed or, to the Company's knowledge, proposed against it.

(s) COMPANY NOT AN "INVESTMENT COMPANY". The Company has been advised of the rules and requirements under the Investment Company Act of 1940, as amended (the "Investment Company Act"). The Company is not, and after receipt of payment for the Common Shares will not be, an "investment company" within the meaning of the Investment Company Act and will conduct its business in a manner so that it will not become subject to the Investment Company Act.

(t) INSURANCE. Except as otherwise disclosed in the Prospectus, the Company is insured by recognized, financially sound and reputable institutions with policies in such amounts and with such deductibles and covering such risks as the Company has deemed adequate and customary for its business including, but not limited to, policies covering real and personal property owned or leased by the Company against theft, damage, destruction, acts of vandalism and earthquakes. The Company has no reason to believe that it will not be able to
(i) renew its existing insurance coverage as and when such policies expire or
(ii) obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not result in a Material Adverse Change.

(u) NO PRICE STABILIZATION OR MANIPULATION. The Company has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of the Common Stock to facilitate the sale or resale of the Common Shares. The Company acknowledges that the Underwriters may engage in passive market making transactions in the Common Shares on the Nasdaq National Market in accordance with Regulation M under the Securities Exchange Act of 1934, as amended (the "Exchange Act").

(v) RELATED PARTY TRANSACTIONS. There are no business relationships or related-party transactions involving the Company or, to the Company's knowledge, any other person required to be described in the Prospectus which have not been described as required, and all related-party transactions have been reviewed and approved by the Company's Board of Directors.

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(w) DISCLOSURE CONTROLS AND PROCEDURES. The Company has established and maintains "disclosure controls and procedures" (as such term is defined in Rule 13a-15 under the Exchange Act), which (i) are designed to ensure that information required to be disclosed by the Company in the reports that if files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission's rules and forms,
(ii) are designed to ensure that information required to be disclosed by the Company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the Company's management, including its principal executive officer and principal financial officer, as appropriate to allow timely decisions regarding required disclosure and (iii) are effective in all material respects to perform the functions for which they were established. Based on the evaluation of the Company's disclosure controls and procedures described above, the Company is not aware of (a) any significant deficiency in the design or operation of its internal controls which could adversely affect the Company's ability to record, process, summarize and report financial data or, (b) any material weaknesses in its internal controls or (c) any fraud, whether or not material, that involves management or other employees who have a significant role in the Company's internal controls.

(x) NO UNLAWFUL CONTRIBUTIONS OR OTHER PAYMENTS. Neither the Company nor, to the Company's knowledge, any employee or agent of the Company, has made any contribution or other payment to any official of, or candidate for, any federal, state or foreign office in violation of any law or of the character required to be disclosed in the Prospectus.

(y) COMPANY'S ACCOUNTING SYSTEM. The Company maintains a system of accounting controls sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management's general or specific authorization; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles as employed in the United States and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management's general or specific authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(z) COMPLIANCE WITH ENVIRONMENTAL LAWS. Except as would not, individually or in the aggregate, result in a Material Adverse Change (i) the Company is in compliance with all federal, state, local and foreign laws, regulations, permits and other governmental authorizations relating to pollution or protection of human health or the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to emissions, discharges, releases or threatened releases of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum and petroleum products (collectively, "Materials of Environmental Concern"), or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Materials of Environmental Concern (collectively, "Environmental Laws"), and the Company has not received any written communication, whether from a governmental authority or an employee, that alleges that the Company is not in compliance with any Environmental Law;
(ii) there is no claim, action or cause of action filed with a court or governmental authority, no investigation with respect to which the Company has received written notice, and no written notice by any person or entity alleging potential liability for investigatory costs, cleanup costs, governmental response costs, natural resources damages,

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property damages, personal injuries, attorneys' fees or penalties arising out of, based on or resulting from the presence, or release into the environment, of any Materials of Environmental Concern at any location owned, leased or operated by the Company, now or in the past (collectively, "Environmental Claims"), pending or, to the Company's knowledge, threatened against the Company or any person or entity whose liability for any Environmental Claim the Company has retained or assumed either contractually or by operation of law; and (iii) to the Company's knowledge, there are no past or present actions, activities, circumstances, conditions, events or incidents, including, without limitation, the release, emission, discharge, presence or disposal of any Materials of Environmental Concern, that reasonably could be expected to result in non-compliance with any Environmental Law or form the basis of a potential Environmental Claim against the Company or against any person or entity whose liability for any Environmental Claim the Company has retained or assumed either contractually or, to the Company's knowledge, by operation of law.

(aa) ERISA COMPLIANCE. The Company and each "Employee Plan" (as defined below) established or maintained by the Company or its "ERISA Affiliates" (as defined below) are in compliance in all material respects with the Employee Retirement Income Security Act of 1974, as amended, and the regulations and published interpretations thereunder (collectively, "ERISA"), the Internal Revenue Code of 1986, as amended, and the regulations and published interpretations thereunder (collectively, the "Code"), and all other applicable laws and regulations. "Employee Plan" means all employee benefit plans (as defined in Section 3(3) of ERISA) and all bonus, stock, option or other security plans; stock or other security purchase agreements; stock or other security appreciation rights; incentive, deferred compensation, retirement or supplemental retirement plans; severance, golden parachute, vacation, cafeteria, dependent care, medical care and employee assistance benefits or programs; education or tuition assistance programs; insurance; other similar fringe or employee benefit plans, programs or arrangements; and any current or former employment or executive compensation or severance agreements, written or otherwise, which have ever been sponsored or maintained or entered into for the benefit of, or relating to, any present or former employee or director of the Company and with respect to which the Company may have any material liability. "ERISA Affiliate" means, with respect to the Company, any member of any group of organizations described in Sections 414(b),(c),(m) or (o) of the Code of which the Company is a member. No "reportable event" (as defined under Section 4043 of ERISA), other than reportable events for which the giving of notice has been waived, has occurred or is reasonably expected to occur with respect to any "employee benefit plan" established or maintained by the Company or any of its ERISA Affiliates. No "employee benefit plan" established or maintained by the Company or any of its ERISA Affiliates, if such "employee benefit plan" were terminated, would have any "amount of unfunded benefit liabilities" (as defined under Section 4001(a)(18) of ERISA). Neither the Company nor any of its ERISA Affiliates has incurred or reasonably expects to incur any material liability under (i) Title IV of ERISA with respect to the termination of, or withdrawal from, any "employee benefit plan" or (ii) Sections 412, 4971, 4975 or 4980B of the Code. Each "employee benefit plan" established or maintained by the Company that is intended to be qualified under Section 401(a) of the Code is so qualified, and nothing has occurred, whether by action or failure to act, which would reasonably be expected to cause the loss of such qualification. No "prohibited transaction" (as defined under ERISA or Section 4975 of the Code or "accumulated funding deficiency" (as defined under ERISA) or any of the events set forth in Section 4043(b) of ERISA (other than events with respect to which the 30-day notice

9

requirement under Section 4043 of ERISA has been waived) has occurred with respect to any employee benefit plan which could have a Material Adverse Change. No Employee Plan is an "employee pension benefit plan" (within the meaning of
Section 3(2) of ERISA) subject to Title IV of ERISA, and neither the Company nor any ERISA Affiliate has ever partially or fully withdrawn from any such plan. No Employee Plan is a Multiemployer Plan or "single-employer plan under multiple controlled groups" as described in Section 4063 of ERISA, and neither the Company nor any ERISA Affiliate has ever contributed to or had an obligation to contribute, or incurred any liability in respect of a contribution, to any Multiemployer Plan (as such term is defined in Section 3(37) of ERISA). Each Employee Plan that is a "group health plan" (within the meaning of Code Section 5000(b)(1)) has been operated in material compliance with all laws applicable to such plan, its terms, and with the group health plan continuation coverage requirements of Section 4980B of the Code and Sections 601 through 608 of ERISA ("COBRA Coverage"), Section 4980D of the Code and Sections 701 through 707 of ERISA, Title XXII of the Public Health Service Act and the provisions of the Social Security Act, to the extent such requirements are applicable. No Employee Plan or written or oral agreement exists which obligates the Company or any ERISA Affiliate to provide health care coverage, medical, surgical, hospitalization, death or similar benefits (whether or not insured) to any employee, former employee or director of the Company or any ERISA Affiliate following such employee's, former employee's or director's termination of employment with the Company or any ERISA Affiliate, other than COBRA Coverage or other similar applicable law. No Employee Plan currently or previously maintained by the Company provides any post-termination health care or life insurance benefits, and neither the Company nor its ERISA Affiliates has any obligations (whether written or oral) to provide any post-termination benefits in the future (except for COBRA Coverage or coverage required by any other applicable law).

(bb) BROKERS. Except as contemplated by this Agreement, there is no broker, finder or other party that is entitled to receive from the Company any brokerage or finder's fee or other fee or commission as a result of any transactions contemplated by this Agreement.

(cc) NO OUTSTANDING LOANS OR OTHER INDEBTEDNESS. There are no outstanding loans, advances (except normal advances for business expenses in the ordinary course of business) or guarantees of indebtedness by the Company to or for the benefit of any of the officers or directors of the Company or any of the family members of any of them, except as disclosed in the Registration Statement and Prospectus.

(dd) COMPLIANCE WITH LAWS. The Company is conducting business in compliance with all applicable laws, rules and regulations of the jurisdictions in which it is conducting business, except where the failure to so comply would not result in a Material Adverse Change.

(ee) DIRECTED SHARE PROGRAM. (i) The Registration Statement, the Prospectus and any preliminary prospectus comply, and any further amendments or supplements thereto will comply, with all applicable laws or regulations of foreign jurisdictions in which the Prospectus or any preliminary prospectus, as amended or supplemented, if applicable, are distributed in connection with the Directed Share Program, and (ii) no authorization, approval, consent, license, order, registration or qualification of or with any government, governmental instrumentality or court, other than such as have been obtained, is necessary under the securities laws and regulations of foreign jurisdictions in which the Directed Shares are offered outside the

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United States. The Company has not offered, or caused the Underwriters to offer, any Common Shares to any person pursuant to the Directed Share Program with the intent to unlawfully influence (i) a customer or supplier of the Company to alter the customer's or supplier's level or type of business with the Company or
(ii) a trade journalist or publication to write or publish favorable information about the Company or its products.

(ff) NO LABOR DISPUTES. No labor disturbance by the employees of the Company exists or, to the best knowledge of the Company, is imminent which might be expected to result in a Material Adverse Change. The Company is not aware that any officer or significant group of employees of the Company plans to terminate employment with the Company.

(gg) MATERIAL CONTRACTS. There is no franchise, lease, contract, agreement or document required by the Securities Act to be described in the Prospectus or to be filed as an exhibit to the Registration Statement which is not described in all material respects or filed therein as required. Other than as described in the Prospectus, no such franchise, lease, contract or agreement has been terminated for convenience or default by the Company or any of the other parties thereto, and the Company has not received notice of any such pending or threatened termination, except for such pending or threatened suspensions or terminations that would not reasonably be expected to, singularly or in the aggregate, have a Material Adverse Change.

(hh) NO MARGIN SECURITIES. The Company does not own any "margin securities" as that term is defined in Regulation U of the Board of Governors of the Federal Reserve System (the "Federal Reserve Board"), and none of the proceeds from the sale of Common Shares will be used, directly or indirectly, for the purpose of purchasing or carrying any margin security, for the purpose of reducing or retiring any indebtedness which was originally incurred to purchase or carry any margin security or for any other purpose which might cause any of the Common Shares to be considered a "purpose credit" within the meanings of Regulation T, U or X of the Federal Reserve Board.

(ii) FORWARD-LOOKING STATEMENTS. No forward-looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) contained in the Prospectus has been made without a reasonable basis or has been disclosed other than in good faith.

(jj) SARBANES-OXLEY ACT OF 2002. The Company has taken all necessary actions to ensure that, upon and at all times after the effectiveness of the Registration Statement, it will be in compliance with all applicable material provisions of the Sarbanes-Oxley Act of 2002 and all rules and regulations promulgated thereunder or implementing the provisions thereof (the "Sarbanes-Oxley Act") that are then in effect.

(kk) CORPORATE GOVERNANCE. The Company has taken all necessary actions to ensure that, upon and at all times after the Nasdaq National Market shall have approved the Common Shares for inclusion, it will be in compliance with all applicable corporate governance requirements set forth in the Nasdaq Marketplace Rules that are then in effect.

(ll) COMMUNICATION WITH THE FDA. The Company has (i) orally fairly summarized in all material respects the substance of all of its material communications with representatives of

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the U.S. Food and Drug Administration (the "FDA"); and (ii) is not aware of any pending communication from the FDA that would cause the Company to revise its strategy for seeking marketing approval from the FDA for M-Enoxaparin or any of the Company's other products under development as described in the Registration Statement and Prospectus.

(mm) STUDIES AND OTHER PRECLINICAL TESTS. The animal studies and other preclinical tests conducted by or on behalf of the Company that are described in the Registration Statement and Prospectus or the results of which are referred to in the Registration Statement and Prospectus were and, if still pending, are being conducted in all material respects in accordance with experimental protocols, procedures and controls generally used by qualified experts in the preclinical study of new drugs or diagnostics as applied to comparable products to those being developed by the Company. The descriptions of the results of such studies and tests contained in the Registration Statement and Prospectus are accurate and complete in all material respects.

Any certificate signed by an officer of the Company and delivered to the Representatives or to counsel for the Underwriters shall be deemed to be a representation and warranty by the Company to each Underwriter as to the matters set forth therein.

The Company acknowledges that the Underwriters and, for purposes of the opinions to be delivered pursuant to Section 5 hereof, counsel to the Company and counsel to the Underwriters, will rely upon the accuracy and truthfulness of the foregoing representations and hereby consents to such reliance.

Section 2. PURCHASE, SALE AND DELIVERY OF THE COMMON SHARES.

(a) THE FIRM COMMON SHARES. On the basis of the representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, (i) the Company agrees to issue and sell to the several Underwriters the Firm Common Shares and (ii) the Underwriters agree, severally and not jointly, to purchase from the Company the respective number of Firm Common Shares set forth opposite their names on Schedule A. The purchase price per Firm Common Share to be paid by the several Underwriters to the Company shall be $[___] per share.

(b) THE FIRST CLOSING DATE. Delivery of certificates for the Firm Common Shares to be purchased by the Underwriters and payment therefor shall be made at the offices of BAS, 9 West 57th Street, New York, NY (or such other place as may be agreed to by the Company and the Representatives) at 9:00 a.m. New York time, on [___], or such other time and date not later than 1:30 p.m. New York time, on [___] as the Representatives and the Company shall agree (the time and date of such closing are called the "First Closing Date").

(c) THE OPTIONAL COMMON SHARES; THE SECOND CLOSING DATE. In addition, on the basis of the representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Company hereby grants an option to the several Underwriters to purchase, severally and not jointly, up to an aggregate of [___] Optional Common Shares from the Company at the purchase price per share to be paid by the Underwriters for the Firm Common Shares. The option granted hereunder is for use by the Underwriters solely in covering any over-allotments in connection with the sale and distribution

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of the Firm Common Shares. The option granted hereunder may be exercised at any time (but not more than once) upon notice by the Representatives to the Company, which notice may be given at any time within 30 days after the date of this Agreement. Such notice shall set forth (i) the aggregate number of Optional Common Shares as to which the Underwriters are exercising the option, (ii) the names and denominations in which the certificates for the Optional Common Shares are to be registered and (iii) the time, date and place at which such certificates will be delivered (which time and date may be simultaneous with, but not earlier than, the First Closing Date; and in such case the term "First Closing Date" shall refer to the time and date of delivery of certificates for the Firm Common Shares and the Optional Common Shares). Such time and date of delivery, if subsequent to the First Closing Date, is called the "Second Closing Date" and shall be determined by the Representatives and shall not be earlier than three nor later than five full business days after delivery of such notice of exercise. If any Optional Common Shares are to be purchased, each Underwriter agrees, severally and not jointly, to purchase the number of Optional Common Shares (subject to such adjustments to eliminate fractional shares as the Representatives may determine) that bears the same proportion to the total number of Optional Common Shares to be purchased as the number of Firm Common Shares set forth on Schedule A opposite the name of such Underwriter bears to the total number of Firm Common Shares. The Representatives may cancel the option at any time prior to its expiration by giving written notice of such cancellation to the Company.

(d) PUBLIC OFFERING OF THE COMMON SHARES. The Representatives hereby advise the Company that the Underwriters intend to offer for sale to the public, as described in the Prospectus, their respective portions of the Common Shares as soon after this Agreement has been executed and the Registration Statement has been declared effective as the Representatives, in their sole judgment, have determined is advisable and practicable.

(e) PAYMENT FOR THE COMMON SHARES. Payment for the Common Shares shall be made at the First Closing Date (and, if applicable, at the Second Closing Date) by wire transfer of immediately available United States funds to an account at a bank acceptable to SG Cowen and BAS jointly, payable to the order of the Company.

It is understood that the Representatives have been authorized, for their own respective accounts and the accounts of the several Underwriters, to accept delivery of and receipt for, and make payment of the purchase price for, the Firm Common Shares and any Optional Common Shares the Underwriters have agreed to purchase. Each of SG Cowen and BAS, individually and not as a Representative of the Underwriters, may (but shall not be obligated to) make payment for any Common Shares to be purchased by any Underwriter whose funds shall not have been received by the Representatives by the First Closing Date or the Second Closing Date, as the case may be, for the account of such Underwriter, but any such payment shall not relieve such Underwriter from any of its obligations under this Agreement.

(f) DELIVERY OF THE COMMON SHARES. The Company shall deliver, or cause to be delivered, to the Representatives for the accounts of the several Underwriters certificates for the Firm Common Shares at the First Closing Date, against the irrevocable release of a wire transfer of immediately available United States funds for the amount of the purchase price therefor. The Company shall also deliver, or cause to be delivered, to the Representatives for the accounts of the several Underwriters, certificates for the Optional Common Shares the Underwriters have

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agreed to purchase at the First Closing Date or the Second Closing Date, as the case may be, against the irrevocable release of a wire transfer of immediately available United States funds for the amount of the purchase price therefor. The certificates for the Common Shares shall be in definitive form and registered in such names and denominations as the Representatives shall have requested at least two full business days prior to the First Closing Date (or the Second Closing Date, as the case may be) and shall be made available for inspection on the business day preceding the First Closing Date (or the Second Closing Date, as the case may be) at a location in New York City as the Representatives may designate. Time shall be of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Underwriters.

Section 3. ADDITIONAL COVENANTS OF THE COMPANY. The Company further covenants and agrees with each Underwriter as follows:

(a) REPRESENTATIVES' REVIEW OF PROPOSED AMENDMENTS AND SUPPLEMENTS. During such period beginning on the date hereof and ending on the later of the First Closing Date or such date, as in the opinion of counsel for the Underwriters, the Prospectus is no longer required by law to be delivered in connection with sales by an Underwriter or dealer (the "Prospectus Delivery Period"), prior to amending or supplementing the Registration Statement (including any registration statement filed under Rule 462(b) under the Securities Act) or the Prospectus, the Company shall furnish to the Representatives for review a copy of each such proposed amendment or supplement, and the Company shall not file any such proposed amendment or supplement to which the Representatives reasonably object.

(b) SECURITIES ACT COMPLIANCE. After the date of this Agreement, the Company shall promptly advise the Representatives in writing (i) of the receipt of any comments of, or requests for additional or supplemental information from, the Commission, (ii) of the time and date of any filing of any post-effective amendment to the Registration Statement or any amendment or supplement to any preliminary prospectus or the Prospectus, (iii) of the time and date that any post-effective amendment to the Registration Statement becomes effective and
(iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or any post-effective amendment thereto or of any order preventing or suspending the use of any preliminary prospectus or the Prospectus, or of any proceedings to remove, suspend or terminate from listing or quotation the Common Stock from any securities exchange or inter-dealer quotation system or securities market upon which it is listed for trading or included or designated for quotation, or of the threatening or initiation of any proceedings for any of such purposes. If the Commission shall enter any such stop order at any time, the Company will use its best efforts to obtain the lifting of such order at the earliest possible moment. Additionally, the Company shall comply with the provisions of Rules
424(b), 430A and 434, as applicable, under the Securities Act and will use its reasonable efforts to confirm that any filings made by the Company under such Rule 424(b) were received in a timely manner by the Commission. The Company will supply the Representatives with copies of all correspondence to and from, and all documents issued to and by, the Commission in connection with the registration of the Common Shares under the Securities Act.

(c) AMENDMENTS AND SUPPLEMENTS TO THE PROSPECTUS AND OTHER SECURITIES ACT MATTERS. If, during the Prospectus Delivery Period, any event shall occur or condition exist as a

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result of which it is necessary to amend or supplement the Prospectus in order to make the statements therein, in the light of the circumstances when the Prospectus is delivered to a purchaser, not misleading, or if in the opinion of the Representatives or counsel for the Underwriters it is otherwise necessary to amend or supplement the Prospectus to comply with law, the Company agrees, at its own expense, to promptly prepare (subject to Section 3(a) hereof), file with the Commission and furnish to the Underwriters and to dealers, amendments or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances when the Prospectus is delivered to a purchaser, be misleading, or so that the Prospectus, as amended or supplemented, will comply with law. The Company will not take any action prior to the expiration of the Prospectus Delivery Period which would require the Prospectus to be amended or supplemented pursuant to this Section 3(c). The Underwriters shall cease using the Prospectus upon receiving written notice from the Company that an amendment or supplement is required under this Section 3(c).

(d) COPIES OF ANY AMENDMENTS AND SUPPLEMENTS TO THE PROSPECTUS. The Company agrees to furnish the Representatives, without charge, during the Prospectus Delivery Period, as many copies of the Prospectus and any amendments and supplements thereto as the Representatives may reasonably request.

(e) BLUE SKY COMPLIANCE. The Company shall cooperate with the Representatives and counsel for the Underwriters to qualify or register the Common Shares for sale under (or obtain exemptions from the application of) the state securities or blue sky laws or Canadian provincial securities laws of those jurisdictions designated by the Representatives, shall comply with such laws and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Common Shares. The Company shall not be required to qualify as a foreign corporation or to take any action that would subject it to general service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign corporation. The Company will advise the Representatives promptly of the suspension of the qualification or registration of (or any such exemption relating to) the Common Shares for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, the Company shall use its best efforts to obtain the withdrawal thereof at the earliest possible moment.

(f) USE OF PROCEEDS. The Company shall apply the net proceeds from the sale of the Common Shares sold by it in the manner described under the caption "Use of Proceeds" in the Prospectus.

(g) TRANSFER AGENT. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Common Stock.

(h) EARNINGS STATEMENT. As soon as practicable, the Company will make generally available to its security holders and to the Representatives an earnings statement (which need not be audited) covering the twelve-month period ending [___] that satisfies the provisions of Section 11(a) of the Securities Act.

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(i) PERIODIC REPORTING OBLIGATIONS. During the Prospectus Delivery Period, the Company shall file, on a timely basis, with the Commission and the Nasdaq National Market all reports and documents required to be filed under the Exchange Act. Additionally, the Company shall report the use of proceeds from the issuance of the Common Shares as may be required under Rule 463 under the Securities Act.

(j) DIRECTED SHARE PROGRAM. In connection with the Directed Share Program, the Company will use reasonable efforts to ensure that the Directed Shares will be restricted to the extent required by the NASD under NASD Rule 2790 from sale, transfer, assignment, pledge or hypothecation for a period following the date of the effectiveness of the Registration Statement. If so required, the Company will direct the transfer agent to place stop transfer restrictions upon such securities for such period of time. Should the Company release, or seek to release, from such restrictions any of the Directed Shares, the Company agrees to reimburse the Underwriters for any reasonable expenses (including, without limitation, legal expenses) they incur in connection with such release.

(k) QUOTATION. The Company will use its best efforts to include, subject to notice of issuance, the Common Shares on the Nasdaq National Market.

(l) AGREEMENT NOT TO OFFER OR SELL ADDITIONAL SECURITIES. During the period commencing on the date hereof and ending on the 180th day following the date of the Prospectus, the Company will not, without the prior written consent of SG Cowen and BAS jointly (which consent may be withheld at the sole discretion of SG Cowen or BAS), directly or indirectly, sell, offer, contract or grant any option to sell, pledge, transfer or establish an open "put equivalent position" within the meaning of Rule 16a-1(h) under the Exchange Act, or otherwise dispose of or transfer, or announce the offering of, or file any registration statement under the Securities Act (other than a registration statement on Form S-8) in respect of, any shares of Common Stock, options or warrants to acquire shares of the Common Stock or securities exchangeable or exercisable for or convertible into shares of Common Stock (other than as contemplated by this Agreement with respect to the Common Shares); provided, however, that the Company may issue shares of its Common Stock or options to purchase its Common Stock, or Common Stock upon exercise of options, pursuant to any stock option, stock bonus or other stock plan or arrangement described in the Registration Statement and Prospectus, but only if the holders of such shares, options, or shares issued upon exercise of such options, agree in writing not to sell, offer, dispose of or otherwise transfer any such shares or options during such 180 day period without the prior written consent of SG Cowen and BAS jointly (which consent may be withheld at the sole discretion of the SG Cowen or BAS).

(m) INVESTMENT LIMITATION. The Company shall not invest, or otherwise use the proceeds received by the Company from its sale of the Common Shares in such a manner as would require the Company or any of its subsidiaries to register as an investment company under the Investment Company Act.

(n) NO MANIPULATION OF PRICE. The Company will not take, directly or indirectly, any action designed to cause or result in, or that has constituted or might reasonably be expected to constitute, the stabilization or manipulation of the price of any securities of the Company.

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(o) EXISTING LOCK-UP AGREEMENT. The Company will enforce all existing agreements between the Company and any of its security holders that prohibit the sale, transfer, assignment, pledge or hypothecation of any of the Company's securities in connection with the Company's initial public offering. In addition, the Company will direct the transfer agent to place stop transfer restrictions upon any such securities of the Company that are bound by such existing "lock-up" agreements for the duration of the periods contemplated in such agreements.

(p) NO PRESS RELEASES OR CONFERENCES. Prior to the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date, the Company will not issue any press release or other communication directly or indirectly or hold any press conference with respect to the Company, its condition, financial or otherwise, or earnings, business affairs or business prospects, without first providing written notification to each Representative.

(q) NO ACTIVE TRADING IN OR RAISING THE PRICE OF THE COMMON SHARES. In connection with the offering of the Common Shares, until SG Cowen and BAS shall have jointly notified the Company of the completion of the resale of the Common Shares, the Company will not, and will cause its affiliated purchasers (as defined in Regulation M under the Exchange Act) not to, either alone or with one or more other persons, bid for or purchase, for any account in which it or any of its affiliated purchasers has a beneficial interest, any Common Shares, or attempt to induce any person to purchase any Common Shares; and will not make bids or purchase for the purpose of creating actual, or apparent, active trading in or of raising the price of the Common Shares.

Section 4. PAYMENT OF EXPENSES. The Company agrees to pay all costs, fees and expenses incurred in connection with the performance of its obligations hereunder and in connection with the transactions contemplated hereby, including, without limitation, (i) all expenses incident to the issuance and delivery of the Common Shares (including all printing and engraving costs), (ii) all fees and expenses of the registrar and transfer agent of the Common Stock,
(iii) all necessary issue, transfer and other stamp taxes in connection with the issuance and sale of the Common Shares to the Underwriters, (iv) all fees and expenses of the Company's counsel, independent public or certified public accountants and other advisors, (v) all costs and expenses incurred in connection with the preparation, printing, filing, shipping and distribution of the Registration Statement (including financial statements, exhibits, schedules, consents and certificates of experts), each preliminary prospectus and the Prospectus, and all amendments and supplements thereto, (vi) all filing fees, attorneys' fees and expenses incurred by the Company or the Underwriters in connection with qualifying or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Common Shares for offer and sale under the state securities or blue sky laws or the provincial securities laws of Canada, and, if requested by the Representatives, preparing and printing a "Blue Sky Survey" or memorandum, and any supplements thereto, and advising the Underwriters of such qualifications, registrations and exemptions,
(vii) the filing fees incident to, and the reasonable fees and expenses of counsel for the Underwriters in connection with, the NASD's review and approval of the Underwriters' participation in the offering and distribution of the Common Shares, (viii) the fees and expenses associated with including the Common Stock on the Nasdaq National Market, (ix) the costs and expenses of the Company relating to investor presentations on any "road show" undertaken in connection with the marketing of the offering of the Common Shares, including, without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations with the

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prior approval of the Company, travel and lodging expenses of the representatives and officers of the Company and any such consultants, and the costs of any aircraft chartered in connection with the road show, (x) all other fees, costs and expenses referred to in Item 13 of Part II of the Registration Statement, and (xi) all out-of-pocket costs and expenses of the Underwriters, including the fees and disbursements of counsel for the Underwriters, in connection with matters related to the Directed Shares which are designated by the Company for sale to Participants. Except as provided in this Section 4,
Section 6, Section 8 and Section 9 hereof, the Underwriters shall pay their own expenses, including the fees and disbursements of their counsel.

Section 5. CONDITIONS OF THE OBLIGATIONS OF THE UNDERWRITERS. The obligations of the several Underwriters to purchase and pay for the Common Shares as provided herein on the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date, shall be subject to the accuracy of the representations and warranties on the part of the Company set forth in Section 1 hereof as of the date hereof and as of the First Closing Date as though then made and, with respect to the Optional Common Shares, as of the Second Closing Date as though then made, to the timely performance by the Company of its covenants and other obligations hereunder, and to each of the following additional conditions:

(a) ACCOUNTANTS' COMFORT LETTER. On the date hereof, each of the Representatives shall have received from Ernst & Young LLP, independent public accountants for the Company, a letter dated the date hereof addressed to the Underwriters, in form and substance satisfactory to the Representatives, (i) confirming that they are independent certified public accountants with respect to the Company within the meaning of the Securities Act and (ii) containing statements and information of the type ordinarily included in accountants' "comfort letters" to underwriters, delivered according to Statement of Auditing Standards No. 72 (or any successor bulletin), with respect to the audited and unaudited financial statements and certain financial information contained in the Registration Statement and the Prospectus (and the Representatives shall have received an additional [___] conformed copies of such accountants' letter for each of the several Underwriters).

(b) COMPLIANCE WITH REGISTRATION REQUIREMENTS; NO STOP ORDER; NO OBJECTION FROM NASD. For the period from and after effectiveness of this Agreement and prior to the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date:

(i) the Company shall have filed the Prospectus with the Commission (including the information required by Rule 430A under the Securities Act) in the manner and within the time period required by Rule 424(b) under the Securities Act; or the Company shall have filed a post-effective amendment to the Registration Statement containing the information required by such Rule 430A, and such post-effective amendment shall have become effective; or, if the Company elected to rely upon Rule 434 under the Securities Act and obtained the Representatives' consent thereto, the Company shall have filed a Term Sheet with the Commission in the manner and within the time period required by such Rule 424(b);

(ii) no stop order suspending the effectiveness of the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment to the

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Registration Statement, shall be in effect and no proceedings for such purpose shall have been instituted or threatened by the Commission; and

(iii) the NASD shall have raised no objection to the fairness and reasonableness of the underwriting terms and arrangements.

(c) NO MATERIAL ADVERSE CHANGE OR RATINGS AGENCY CHANGE. For the period from and after the date of this Agreement and prior to the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date, in the judgment of the Representatives, there shall not have occurred any Material Adverse Change.

(d) OPINION OF COUNSEL FOR THE COMPANY. On each of the First Closing Date and the Second Closing Date, each of the Representatives shall have received the opinion of Wilmer Cutler Pickering Hale and Dorr LLP, counsel for the Company, dated as of such Closing Date, the form of which is attached as Exhibit A (and the Representatives shall have received an additional [___] conformed copies of such counsel's legal opinion for each of the several Underwriters).

(e) OPINION OF COUNSEL FOR THE COMPANY WITH RESPECT TO INTELLECTUAL PROPERTY MATTERS. On each of the First Closing Date and the Second Closing Date, each of the Representatives shall have received (i) the opinion of Fitzpatrick, Cella, Harper & Scinto, the form of which is attached as Exhibit B, and (ii) the opinion of Fish & Richardson P.C. in form and substance satisfactory to the Representatives and counsel for the Underwriters (and the Representatives shall have received an additional [____] conformed copies of such counsels' legal opinions for each of the several Underwriters).

(f) OPINION OF COUNSEL FOR THE UNDERWRITERS. On each of the First Closing Date and the Second Closing Date, each of the Representatives shall have received the opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., counsel for the Underwriters, dated as of such Closing Date, with respect to the matters set forth in paragraphs (i) (with respect to due incorporation and valid existence only), (v), (vi) (with respect to the first sentence and item (A) of the second sentence only) and (vii) of Exhibit A (and the Representatives shall have received an additional [___] conformed copies of such counsel's legal opinion for each of the several Underwriters). In addition, such letter shall also contain the statements set forth in the next to the last paragraph of Exhibit A, including subparagraphs (a) and (b) thereof, but not subparagraph (c).

(g) OFFICERS' CERTIFICATE. On each of the First Closing Date and the Second Closing Date the Representatives shall have received a written certificate executed by the Chairman of the Board, Chief Executive Officer and President of the Company and the Chief Financial Officer or Chief Accounting Officer of the Company, dated as of such First Closing Date or Second Closing Date, whichever the case may be, to the effect set forth in subsection (b)(ii) of this Section 5, and further to the effect that:

(i) Such officers have carefully examined the Registration Statement and the Prospectus and, in their opinion, the Registration Statement and the Prospectus, as of their respective effective dates, did not include any untrue statement of a material fact

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and did not omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading;

(ii) since the effective date of the Registration Statement, no event has occurred which should have been set forth in a supplement or amendment to the Registration Statement or the Prospectus;

(iii) for the period from and after the date of this Agreement and prior to such Closing Date, there has not occurred any Material Adverse Change;

(iv) the representations and warranties of the Company set forth in Section 1 of this Agreement are true and correct with the same force and effect as though expressly made on and as of such First Closing Date or Second Closing Date, whichever the case may be; and

(v) the Company has complied with all the agreements hereunder and satisfied all the conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date.

(h) BRING-DOWN COMFORT LETTER. On each of the First Closing Date and the Second Closing Date the Representatives shall have received from Ernst & Young LLP, independent public accountants for the Company, a letter dated such date, in form and substance satisfactory to the Representatives, to the effect that they reaffirm the statements made in the letter furnished by them pursuant to subsection (a) of this Section 5, except that the specified date referred to therein for the carrying out of procedures shall be no more than five business days prior to the First Closing Date or Second Closing Date, as the case may be (and the Representatives shall have received an additional [___] conformed copies of such accountants' letter for each of the several Underwriters).

(i) LOCK-UP AGREEMENT FROM CERTAIN SECURITY HOLDERS OF THE COMPANY. On or prior to the date hereof, the Company shall have furnished to the Representatives an agreement in the form of Exhibit C hereto from each director, officer and each beneficial owner (as defined and determined according to Rule 13d-3 under the Exchange Act, except that a one hundred eighty day period shall be used rather than the sixty day period set forth therein) of Common Stock, other than the beneficial owners set forth on Schedule B attached hereto, and such agreement shall be in full force and effect on each of the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date.

(j) NOTICE OF A DISCLOSURE VIOLATION. None of the Underwriters shall have discovered and disclosed to the Company on or prior to the First Closing Date or, with respect to the Optional Common Shares, the Second Closing Date, that the Registration Statement or the Prospectus or any amendment or supplement thereto contains an untrue statement of a fact which, in the opinion of counsel for the Underwriters, is material or omits to state any fact which, in the opinion of such counsel, is material and is required to be stated therein or is necessary to make the statements therein not misleading.

(k) AUTHORIZATION OF THIS AGREEMENT AND RELATED TRANSACTIONS. All corporate proceedings and other legal matters incident to the authorization, form and validity of each of

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this Agreement, the Common Shares, the Registration Statement, the Prospectus and all other legal matters relating to this Agreement and the transactions contemplated hereby shall be reasonably satisfactory in all material respects to counsel for the Underwriters.

(l) NO GOVERNMENT PROHIBITIONS. No injunction, restraining order or order of any other nature by any federal or state court of competent jurisdiction or other governmental authority shall have been issued as of the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date, which would prevent the issuance or sale of the Common Shares or materially and adversely affect or potentially materially and adversely affect the business or operations of the Company.

(m) INCLUSION ON THE NASDAQ NATIONAL MARKET. The Nasdaq National Market shall have approved the Common Stock for inclusion, subject only to official notice of issuance and evidence of satisfactory distribution.

(n) AMENDMENT OF SECOND AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT. On or prior to the date hereof, the Company shall have amended the Second Amended and Restated Investors' Rights Agreement, dated as of February 27, 2004, by and among the Company, the persons and entities listed on schedules attached thereto, the Massachusetts Institute of Technology and Silicon Valley Bank, as set forth in Exhibit D attached hereto.

(o) ADDITIONAL DOCUMENTS. On or before each of the First Closing Date and the Second Closing Date, the Representatives and counsel for the Underwriters shall have received such information, documents and opinions as they may reasonably require for the purposes of enabling them to pass upon the issuance and sale of the Common Shares as contemplated herein, or in order to evidence the accuracy of any of the representations and warranties, or the satisfaction of any of the conditions or agreements, herein contained.

If any condition specified in this Section 5 is not satisfied when and as required to be satisfied, this Agreement may be terminated by the Representatives by notice to the Company at any time on or prior to the First Closing Date and, with respect to the Optional Common Shares, at any time on or prior to the Second Closing Date, which termination shall be without liability on the part of any party to any other party, except that Section 4, Section 6,
Section 8 and Section 9 shall at all times be effective and shall survive such termination.

Section 6. REIMBURSEMENT OF UNDERWRITERS' EXPENSES. If this Agreement is terminated by the Representatives pursuant to Section 5 or Section 11, or if the sale to the Underwriters of the Common Shares on the First Closing Date is not consummated because of any refusal, inability or failure on the part of the Company to perform any agreement herein or to comply with any provision hereof, the Company agrees to reimburse the Representatives and the other Underwriters (or such Underwriters as have terminated this Agreement with respect to themselves), severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred by the Representatives and the Underwriters in connection with the proposed purchase and the offering and sale of the Common Shares, including, but not limited to, fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone charges.

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Section 7. EFFECTIVENESS OF THIS AGREEMENT. This Agreement shall not become effective until the later of (i) the execution of this Agreement by the parties hereto and (ii) notification by the Commission to the Company and the Representatives of the effectiveness of the Registration Statement under the Securities Act.

Prior to such effectiveness, this Agreement may be terminated by any party by notice to each of the other parties hereto, and any such termination shall be without liability on the part of (a) the Company to any Underwriter, except that if this Agreement is terminated by the Company pursuant to this
Section 7, the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters, severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred by the Representatives and the Underwriters in connection with the proposed purchase and the offering and sale of the Common Shares, including, but not limited to, fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone charges, (b) any Underwriter to the Company, or (c) any party hereto to any other party except that the provisions of Section 8 and
Section 9 shall at all times be effective and shall survive such termination.

Section 8. INDEMNIFICATION.

(a) INDEMNIFICATION OF THE UNDERWRITERS. The Company agrees to indemnify and hold harmless each Underwriter, its officers and employees, and each person, if any, who controls any Underwriter within the meaning of the Securities Act and the Exchange Act against any loss, claim, damage, liability or expense, as incurred, to which such Underwriter or such controlling person may become subject, under the Securities Act, the Exchange Act or other federal or state statutory law or regulation, or, if applicable, the laws or regulations of foreign jurisdictions where Directed Shares have been offered, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of the Company), insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon, in whole or in part, (A)(i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any amendment thereto, including any information deemed to be a part thereof pursuant to Rule 430A or Rule 434 under the Securities Act, or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading; or (ii) any untrue statement or alleged untrue statement of a material fact contained in any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; or (iii) any inaccuracy in the representations and warranties of the Company contained herein; or (iv) any failure of the Company to perform its obligations hereunder or under law; or (v) any act or failure to act or any alleged act or failure to act by any Underwriter in connection with, or relating in any manner to, the Common Stock or the offering contemplated hereby, and which is included as part of or referred to in any loss, claim, damage, liability or action arising out of or based upon any matter covered by clause (i) or (ii) above, provided that the Company shall not be liable under this clause (v) to the extent that a court of competent jurisdiction shall have determined by a final judgment that such loss, claim, damage, liability or action resulted directly from any such acts or failures to act undertaken or omitted to be taken by such Underwriter through its bad faith or willful misconduct, and (B) the violation of any

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applicable laws or regulations of foreign jurisdictions where Directed Shares have been offered; and to reimburse each Underwriter and each such controlling person for any and all expenses (including the fees and disbursements of counsel chosen by SG Cowen and/or BAS) as such expenses are reasonably incurred by such Underwriter or such controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action; provided, however, that the foregoing indemnity agreement shall not apply to any loss, claim, damage, liability or expense to the extent, but only to the extent, arising out of or based upon any untrue statement or alleged untrue statement or omission or alleged omission made in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use in the Registration Statement, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto); and provided, further, that with respect to any preliminary prospectus, the foregoing indemnity agreement shall not inure to the benefit of any Underwriter from whom the person asserting any loss, claim, damage, liability or expense purchased Common Shares, or any person controlling such Underwriter, if copies of the Prospectus were timely delivered to the Underwriter pursuant to Section 2 and a copy of the Prospectus (as then amended or supplemented if the Company shall have furnished any amendments or supplements thereto) was not sent or given by or on behalf of such Underwriter to such person, if required by law so to have been delivered, at or prior to the written confirmation of the sale of the Common Shares to such person, and if the Prospectus (as so amended or supplemented) would have cured the defect giving rise to such loss, claim, damage, liability or expense. The indemnity agreement set forth in this Section 8(a) shall be in addition to any liabilities that the Company may otherwise have.

(b) INDEMNIFICATION OF THE COMPANY, ITS DIRECTORS AND OFFICERS. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, each of its directors, each of its officers who signed the Registration Statement and each person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act, against any loss, claim, damage, liability or expense, as incurred, to which the Company, or any such director, officer or controlling person may become subject, under the Securities Act, the Exchange Act, or other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of such Underwriter), insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon any untrue or alleged untrue statement of a material fact contained in the Registration Statement, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), or arises out of or is based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Registration Statement, any preliminary prospectus, the Prospectus (or any amendment or supplement thereto), in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use therein; and to reimburse the Company, or any such director, officer or controlling person for any legal and other expense reasonably incurred by the Company, or any such director, officer or controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action. The Company hereby acknowledges that the only information that the Underwriters have furnished to the Company expressly for use in the Registration Statement, any preliminary prospectus or the Prospectus (or any amendment

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or supplement thereto) are the statements set forth (A) in the first paragraph (including the language contained in the four bullets following such paragraph) under the heading "Stabilization, Short Positions and Penalty Bids," and under the headings "Passive Market Making" and "Prospectus Delivery," in each case under the caption "Underwriting" in the Prospectus and (B) in the table in the first paragraph, as well as in the fourth paragraph under the caption "Underwriting" in the Prospectus; and the Underwriters confirm that such statements are correct. The indemnity agreement set forth in this Section 8(b) shall be in addition to any liabilities that each Underwriter may otherwise have.

(c) NOTIFICATIONS AND OTHER INDEMNIFICATION PROCEDURES. Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof, but the omission to notify the indemnifying party will not relieve it from any liability which it may have to any indemnified party for contribution or otherwise than under the indemnity agreement contained in this Section 8 or to the extent it is not prejudiced as a proximate result of such failure. In case any such action is brought against any indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will be entitled to participate in, and, to the extent that it shall elect, jointly with all other indemnifying parties similarly notified, by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, if the defendants in any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that a conflict may arise between the positions of the indemnifying party and the indemnified party in conducting the defense of any such action or that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, the indemnified party or parties shall have the right to select separate counsel to assume such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt of notice from the indemnifying party to such indemnified party of such indemnifying party's election to assume the defense of such action and approval by the indemnified party of counsel, the indemnifying party will not be liable to such indemnified party under this Section 8 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof unless (i) the indemnified party shall have employed separate counsel in accordance with the proviso to the next preceding sentence (it being understood, however, that the indemnifying party shall not be liable for the expenses of more than one separate counsel (together with local counsel), approved by the indemnifying party (SG Cowen and BAS jointly in the case of Section 8(b) and
Section 9), representing the indemnified parties who are parties to such action) or (ii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of commencement of the action, in each of which cases the fees and expenses of counsel shall be at the expense of the indemnifying party.

(d) SETTLEMENTS. The indemnifying party under this Section 8 shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party against any loss, claim, damage, liability or expense by reason

24

of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by Section 8(c) hereof, the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is or could have been a party and indemnity was or could have been sought hereunder by such indemnified party, unless such settlement, compromise or consent includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such action, suit or proceeding.

(e) INDEMNIFICATION FOR DIRECTED SHARES. In connection with the offer and sale of the Directed Shares, the Company agrees to indemnify and hold harmless the Underwriters from and against any and all losses, liabilities, claims, damages and expenses incurred by them as a result of the failure of the Participants to pay for and accept delivery of Directed Shares which, by the end of the first business day following the date of this Agreement, were subject to a properly confirmed agreement to purchase. The Company agrees to indemnify and hold harmless the Designated Underwriter, its officer and employees, and each person, if any, who controls the Designated Underwriter within the meaning of the Securities Act or the Exchange Act against any loss, claim, damage, liability or expense, as incurred, to which such Designated Underwriter or such controlling person may become subject, which is (i) caused by any untrue statement or alleged untrue statement of a material fact contained in any material prepared by or with the consent of the Company for distribution to Participants in connection with the Directed Share Program or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading; (ii) caused by the failure of any Participant to pay for and accept delivery of Directed Shares that such Participant agreed to purchase; or (iii) related to, arising out of, or in connection with the Directed Share Program. The indemnity agreement set forth in this Section 8(e) shall be in addition to any liabilities that the Company may otherwise have.

Section 9. CONTRIBUTION. If the indemnification provided for in Section 8 is for any reason held to be unavailable to or otherwise insufficient to hold harmless an indemnified party in respect of any losses, claims, damages, liabilities or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount paid or payable by such indemnified party, as incurred, as a result of any losses, claims, damages, liabilities or expenses referred to therein (i) in such proportion as is appropriate to reflect the relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, from the offering of the Common Shares pursuant to this Agreement or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company, on the one hand, and the Underwriters, on the other hand, in connection with the statements or omissions or inaccuracies in the representations and warranties herein which resulted in such losses, claims, damages, liabilities or expenses, as well as any other relevant equitable

25

considerations. The relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, in connection with the offering of the Common Shares pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Common Shares pursuant to this Agreement (before deducting expenses) received by the Company, and the total underwriting discount received by the Underwriters, in each case as set forth on the front cover page of the Prospectus (or, if Rule 434 under the Securities Act is used, the corresponding location on the Term Sheet) bear to the aggregate initial public offering price of the Common Shares as set forth on such cover. The relative fault of the Company, on the one hand, and the Underwriters, on the other hand, shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact or any such inaccurate or alleged inaccurate representation or warranty relates to information supplied by the Company, on the one hand, or the Underwriters, on the other hand, and the parties' relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The amount paid or payable by a party as a result of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include, subject to the limitations set forth in Section 8(c), any legal or other fees or expenses reasonably incurred by such party in connection with investigating or defending any action or claim. The provisions set forth in
Section 8(c) with respect to notice of commencement of any action shall apply if a claim for contribution is to be made under this Section 9; provided, however, that no additional notice shall be required with respect to any action for which notice has been given under Section 8(c) for purposes of indemnification.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 9 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in this Section 9.

Notwithstanding the provisions of this Section 9, no Underwriter shall be required to contribute any amount in excess of the underwriting commissions received by such Underwriter in connection with the Common Shares underwritten by it and distributed to the public. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters' obligations to contribute pursuant to this Section 9 are several, and not joint, in proportion to their respective underwriting commitments as set forth opposite their names in Schedule A. For purposes of this Section 9, each officer and employee of an Underwriter and each person, if any, who controls an Underwriter within the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement, and each person, if any, who controls the Company with the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as the Company.

Section 10. DEFAULT OF ONE OR MORE OF THE SEVERAL UNDERWRITERS. If, on the First Closing Date or the Second Closing Date, as the case may be, any one or more of the several

26

Underwriters shall fail or refuse to purchase Common Shares that it or they have agreed to purchase hereunder on such date, and the aggregate number of Common Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase does not exceed 10% of the aggregate number of the Common Shares to be purchased on such date, the other Underwriters shall be obligated, severally, in the proportions that the number of Firm Common Shares set forth opposite their respective names on Schedule A bears to the aggregate number of Firm Common Shares set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as may be specified by the Representatives with the consent of the non-defaulting Underwriters, to purchase the Common Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date. If, on the First Closing Date or the Second Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Common Shares and the aggregate number of Common Shares with respect to which such default occurs exceeds 10% of the aggregate number of Common Shares to be purchased on such date, and arrangements satisfactory to the Representatives and the Company for the purchase of such Common Shares are not made within 48 hours after such default, this Agreement shall terminate without liability of any party to any other party except that the provisions of Section 4, Section 8 and Section 9 shall at all times be effective and shall survive such termination. In any such case either the Representatives or the Company shall have the right to postpone the First Closing Date or the Second Closing Date, as the case may be, but in no event for longer than seven days in order that the required changes, if any, to the Registration Statement and the Prospectus or any other documents or arrangements may be effected.

As used in this Agreement, the term "Underwriter" shall be deemed to include any person substituted for a defaulting Underwriter under this Section
10. Any action taken under this Section 10 shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

Section 11. TERMINATION OF THIS AGREEMENT. Prior to the First Closing Date this Agreement may be terminated by the Representatives by notice given to the Company if at any time (i) trading or quotation in any of the Company's securities shall have been suspended or limited by the Commission or by the Nasdaq National Market, or trading in securities generally on either the Nasdaq Stock Market or the New York Stock Exchange shall have been suspended or limited, or minimum or maximum prices shall have been generally established on any of such stock exchanges by the Commission or the NASD; (ii) a general banking moratorium shall have been declared by any of federal, New York, Delaware or California authorities; (iii) there shall have occurred any outbreak or escalation of national or international hostilities or any crisis or calamity, or any change in the United States or international financial markets, or any substantial change or development involving a prospective substantial change in United States' or international political, financial or economic conditions, as in the judgment of the Representatives is material and adverse and makes it impracticable to market the Common Shares in the manner and on the terms described in the Prospectus or to enforce contracts for the sale of securities; (iv) in the judgment of the Representatives there shall have occurred any Material Adverse Change; or (v) the Company shall have sustained a loss by strike, fire, flood, earthquake, accident or other calamity of such character as in the judgment of the Representatives may interfere materially with the conduct of the business and operations of the Company regardless of whether or not such loss shall have been insured. Any termination pursuant to this Section 11 shall be without liability on the part of (a) the Company to any

27

Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters pursuant to Sections 4 and 6, (b) any Underwriter to the Company, or (c) of any party hereto to any other party except that the provisions of Section 8 and Section 9 shall at all times be effective and shall survive such termination.

Section 12. REPRESENTATIONS AND INDEMNITIES TO SURVIVE DELIVERY. The respective indemnities, contribution agreements, representations, warranties and other statements of the Company and the several Underwriters set forth in or made pursuant to this Agreement shall remain operative and in full force and effect, regardless of (i) any investigation, or statement as to the results thereof, made by or on behalf of any Underwriter, the officers or employees of any Underwriter, any person controlling any Underwriter, the Company, the officers or employees of the Company, or any person controlling the Company,
(ii) acceptance of the Common Shares and payment for them hereunder and (iii)

termination of this Agreement.

Section 13. NOTICES. All communications hereunder shall be in writing and shall be mailed, hand delivered or telecopied and confirmed to the parties hereto as follows:

If to the Representatives:

SG Cowen & Co., LLC
1221 Avenue of the Americas
New York, NY 10020
Facsimile: (212) 482-8154
Attention: Head of Equity Capital Markets

and

Banc of America Securities LLC
9 West 57th Street

New York,  NY 10019
Facsimile: (212) 933-2217

Attention: Thomas M. Morrison

with a copy to:

SG Cowen & Co., LLC
1221 Avenue of the Americas
New York, NY 10020
Facsimile: (212) 278-7995
Attention: Legal Department

28

and

Banc of America Securities LLC
9 West 57th Street
New York, NY 10019
Facsimile: (212) 583-8567
Attention: Legal Department

and

Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. One Financial Center
Boston, MA 02111
Facsimile: (617) 542-2241
Attention: Jonathan L. Kravetz, Esq.

If to the Company:

Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138
Facsimile: (617) 491-9701
Attention: President

with a copy to:

Wilmer Cutler Pickering Hale and Dorr LLP 60 State Street
Boston, MA 02109
Facsimile: (617) 526-5000
Attention: Steven D. Singer, Esq.

Any party hereto may change the address for receipt of communications by giving written notice to the others.

Section 14. SUCCESSORS. This Agreement will inure to the benefit of and be binding upon the parties hereto, including any substitute Underwriters pursuant to Section 10 hereof, and to the benefit of the employees, officers and directors and controlling persons referred to in Section 8 and Section 9, and in each case their respective successors, and no other person will have any right or obligation hereunder. The term "successors" shall not include any purchaser of the Common Shares as such from any of the Underwriters merely by reason of such purchase.

Section 15. PARTIAL UNENFORCEABILITY. The invalidity or unenforceability of any Section, paragraph or provision of this Agreement shall not affect the validity or enforceability of any other Section, paragraph or provision hereof. If any Section, paragraph or provision of this Agreement is for any reason determined to be invalid or unenforceable, there shall be

29

deemed to be made such minor changes (and only such minor changes) as are necessary to make it valid and enforceable.

Section 16. GOVERNING LAW PROVISIONS. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED IN SUCH STATE.

(a) CONSENT TO JURISDICTION. Any legal suit, action or proceeding arising out of or based upon this Agreement or the transactions contemplated hereby ("Related Proceedings") may be instituted in the federal courts of the United States of America located in the City and County of New York or the courts of the State of New York in each case located in the City and County of New York (collectively, the "Specified Courts"), and each party irrevocably submits to the exclusive jurisdiction (except for proceedings instituted in regard to the enforcement of a judgment of any such court (a "Related Judgment"), as to which such jurisdiction is non-exclusive) of such courts in any such suit, action or proceeding. Service of any process, summons, notice or document by mail to such party's address set forth above shall be effective service of process for any suit, action or other proceeding brought in any such court. The parties irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the Specified Courts and irrevocably and unconditionally waive and agree not to plead or claim in any such court that any such suit, action or other proceeding brought in any such court has been brought in an inconvenient forum.

(b) WAIVER OF IMMUNITY. With respect to any Related Proceeding, each party irrevocably waives, to the fullest extent permitted by applicable law, all immunity (whether on the basis of sovereignty or otherwise) from jurisdiction, service of process, attachment (both before and after judgment) and execution to which it might otherwise be entitled in the Specified Courts, and with respect to any Related Judgment, each party waives any such immunity in the Specified Courts or any other court of competent jurisdiction, and will not raise or claim or cause to be pleaded any such immunity at or in respect of any such Related Proceeding or Related Judgment, including, without limitation, any immunity pursuant to the United States Foreign Sovereign Immunities Act of 1976, as amended.

Section 17. GENERAL PROVISIONS. This Agreement constitutes the entire agreement of the parties to this Agreement and supersedes all prior written or oral and all contemporaneous oral agreements, understandings and negotiations with respect to the subject matter hereof. This Agreement may be executed in two or more counterparts, each one of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement may not be amended or modified unless in writing by all of the parties hereto, and no condition herein (express or implied) may be waived unless waived in writing by each party whom the condition is meant to benefit. The Table of Contents and the Section headings herein are for the convenience of the parties only and shall not affect the construction or interpretation of this Agreement.

Each of the parties hereto acknowledges that it is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including, without limitation, the indemnification provisions of Section 8 and the contribution

30

provisions of Section 9, and is fully informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Sections 8 and 9 hereto fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order to assure that adequate disclosure has been made in the Registration Statement, any preliminary prospectus and the Prospectus (and any amendments and supplements thereto), as required by the Securities Act and the Exchange Act.

If the foregoing is in accordance with your understanding of our agreement, kindly sign and return to the Company the enclosed copies hereof, whereupon this instrument, along with all counterparts hereof, shall become a binding agreement in accordance with its terms.

Very truly yours,

MOMENTA PHARMACEUTICALS, INC.

By:

Alan L. Crane Chairman of the Board, President and Chief Executive Officer

The foregoing Underwriting Agreement is hereby confirmed and accepted by the Underwriters in New York, New York as of the date first above written.

SG COWEN & CO., LLC
BANC OF AMERICA SECURITIES LLC
CIBC WORLD MARKETS CORP.
THINKEQUITY PARTNERS LLC
Acting as Representatives of the
several Underwriters named in
the attached Schedule A.

By: SG COWEN & CO., LLC

By:

Managing Director

By: BANC OF AMERICA SECURITIES LLC

By:

Managing Director

31

SCHEDULE A

                                                                                            NUMBER OF FIRM
                                                                                            COMMON SHARES TO BE
UNDERWRITERS                                                                                PURCHASED
SG Cowen & Co., LLC.....................................................................    [___]
Banc of America Securities LLC..........................................................    [___]
CIBC World Markets Corp.................................................................    [___]
ThinkEquity Partners LLC................................................................    [___]


          Total.........................................................................    [___]

A-1

SCHEDULE B

                                                                                        NUMBER OF SHARES OF
                                                                                     COMMON STOCK BENEFICIALLY
BENEFICIAL OWNER                                                                             OWNED
Rodrigo B. Andrade.................................................................         3,786
Stephen L. Buchwald................................................................         2,512
Yosuf El-Shabrawi..................................................................         1,125
Peter Juhasz.......................................................................         3,786
Dongfang Liu.......................................................................         5,775
Daniel Lohse.......................................................................         1,500

Obadiah J. Plante..................................................................        10,124

B-1

EXHIBIT A

FORM OF LEGAL OPINION OF COMPANY COUNSEL

THE FINAL OPINION IN DRAFT FORM WILL BE ATTACHED AS EXHIBIT A AT THE

TIME THIS AGREEMENT IS EXECUTED.

Opinion of counsel for the Company to be delivered pursuant to Section 5(d) of the Underwriting Agreement.

References to the Prospectus in this Exhibit A include any supplements thereto at the First Closing Date and, with respect to the Optional Common Shares, the Second Closing Date.

(i) The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware and has the corporate power and authority to carry on its business and to own, lease and operate its properties as such business and properties are described in the Prospectus.

(ii) The Company is duly qualified and is in good standing as a foreign corporation authorized to do business in The Commonwealth of Massachusetts.

(iii) All of the outstanding shares of Common Stock have been duly authorized and are validly issued, fully paid and nonassessable, and to such counsel's knowledge, all such shares of Common Stock were issued in compliance with a valid exemption from registration under the Securities Act.

(iv) To such counsel's knowledge, except as described in the Registration Statement, there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Securities Act with respect to any securities of the Company or to require the Company to include such securities with the Common Shares registered pursuant to the Registration Statement, except for any such rights as have been waived.

(v) The Underwriting Agreement has been duly authorized, executed and delivered by the Company.

(vi) The Common Shares have been duly authorized and, when issued and delivered to the Underwriters against payment therefor as provided by the Underwriting Agreement, will be validly issued, fully paid and nonassessable. There are no preemptive rights to purchase any of the Common Shares pursuant to, and each prior issuance of the preferred stock of the Company was not in violation of any preemptive rights under, (A) the Delaware General Corporation law or (B) any agreement filed as an exhibit to the Registration Statement.

(vii) The Registration Statement has become effective under the Securities Act and, to such counsel's knowledge, no stop order suspending its effectiveness has been issued and no proceedings for that purpose are pending before or are threatened by the Commission.

1

(viii) The statements (i) in the Prospectus under the captions (A) "Risk Factors--Risks Relating to Development and Regulatory Approval--If we are not able to demonstrate therapeutic equivalence for our generic versions of complex drugs, including our M-Enoxaparin and our M-Dalteparin products to the satisfaction of the FDA, we will not obtain regulatory approval for commercial sale of our generic product candidates and our future results of operations would be adversely affected (other than the statements contained in the third paragraph under such caption)"; (B) "Risk Factors--Risks Relating to Development and Regulatory Approval--If our preclinical studies and clinical trials for our development candidates are not successful, we will not be able to obtain regulatory approval for commercial sale of our novel or improved drug candidates"; (C) "Risk Factors--Risks Relating to Development and Regulatory Approval--Failure to obtain regulatory approval in foreign jurisdictions would prevent us from marketing our products abroad"; (D) "Risk Factors--Risks Relating to Development and Regulatory Approval--Even if we obtain regulatory approvals, our marketed drugs will be subject to ongoing regulatory review. If we fail to comply with continuing United States and foreign regulations, we could lose our approvals to market drugs and our business would be seriously harmed"; (E) "Risk Factors--Risks Relating to Our Dependence on Third Parties--We depend on third-party manufacturers to manufacture products for us. If in the future we encounter difficulties in our supply or manufacturing arrangements, our business may be materially affected"; (F) "Business--Collaboration and Licenses"; (G) "Business--Manufacturing"; (H) "Business--Regulatory and Legal Matters" (other than the statements under the subsections entitled "Foreign Regulation", "Lovenox Regulatory and Legal Matters" and "Hazardous Materials"); (I) "Description of Capital Stock"; and (J) "Shares Eligible for Future Sale" and (ii) in Item 14 of Part II of the Registration Statement, insofar as such statements constitute matters of law or legal conclusions or summarize the terms of agreements, are correct in all material respects.

(ix) To such counsel's knowledge, there is no action, proceeding or litigation pending or threatened against the Company before any court, governmental or administrative agency or body that is required by the Securities Act or the rules and regulations thereunder to be described in the Registration Statement or Prospectus that is not so described.

(x) Except as may be required under the Securities Act and the rules and regulations of the Commission thereunder and the Exchange Act, and the rules and regulations of the Commission thereunder, no filing with, or authorization, approval, consent, license, order, registration, qualification or decree of, any United States federal or Massachusetts state governmental authority or agency is necessary for the issuance, sale and delivery of the Common Shares by the Company to the Underwriters pursuant to the Underwriting Agreement.

(xi) The execution and delivery of the Underwriting Agreement by the Company and the consummation by the Company of the transactions contemplated thereby will not (A) conflict with or constitute a breach of any of the terms or provisions of, or a default under, the Certificate of Incorporation or By-laws or any indenture, loan agreement, mortgage, lease or other agreement or instrument to which the Company is a party and that is filed as an exhibit to the Registration Statement or (B) violate or conflict with any United States federal or Massachusetts state law, rule or regulation that in our experience is normally applicable in transactions of the type contemplated by the Underwriting Agreement, the Delaware General Corporation Law

2

statute, or any judgment, order or decree specifically naming the Company of which such counsel is aware.

(xii) The Company is not, and after giving effect to the offering and sale of the Common Shares and application of the proceeds thereof, as described in the Prospectus, will not be an "investment company," as such term is defined in the Investment Company Act.

In addition to the opinions provided above, such counsel will confirm to you as follows: In the course of acting as counsel for the Company in connection with the preparation of the Registration Statement and the Prospectus, such counsel has participated in conferences with officers and other representatives of the Company, representatives of and counsel for the Underwriters and representatives of the independent public accountants of the Company, during which the contents of the Registration Statement and the Prospectus were discussed. While the limitations inherent in the independent verification of factual matters and the character of determinations involved in the registration process are such that such counsel is not passing upon and does not assume any responsibility for the accuracy, completeness or fairness of the statements contained in the Registration Statement or the Prospectus (except to the extent expressly set forth in paragraph (viii) above), subject to the foregoing and based on such participation and discussions:

(a) the Registration Statement, as of its effective date, and the Prospectus, as of the date thereof (except for the financial statements, including the notes and schedules thereto, and other financial, statistical and accounting data and information, and information relating to the Underwriters and the method of distribution of the Common Shares by the Underwriters included therein or omitted therefrom, as to which such counsel need express no view) appear on their face to be appropriately responsive in all material respects to the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder;

(b) no facts have come to such counsel's attention that have caused such counsel to believe that (i) the Registration Statement, as of its effective date, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading (except as set forth in the parenthetical in clause (a) above) or (ii) the Prospectus, as of the date it was filed with the Commission pursuant to Rule[s] 424(b)([__] [and 430A]) under the Securities Act or as of the date hereof, contained or contains an untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading (except as set forth in the parenthetical in clause (a) above); and

(c) such counsel is not aware of any contract or other document of a character required by the Securities Act and the applicable rules and regulations of the Commission thereunder to be filed as an exhibit to the Registration Statement that is not so filed.

In rendering such opinion, such counsel may rely (A) as to matters involving the application of laws of any jurisdiction other than the General Corporation Law of the State of Delaware or the federal law of the United States, to the extent they deem proper and specified in such opinion, upon the opinion (which shall be dated the First Closing Date or the Second Closing Date, as the case may be, shall be satisfactory in form and substance to the Underwriters,

3

shall expressly state that the Underwriters may rely on such opinion as if it were addressed to them and shall be furnished to the Representatives) of other counsel of good standing whom they believe to be reliable and who are satisfactory to counsel for the Underwriters; provided, however, that such counsel shall further state that they believe that they and the Underwriters are justified in relying upon such opinion of other counsel, and (B) as to matters of fact, to the extent they deem proper, on certificates of responsible officers of the Company and public officials.

4

EXHIBIT B

FORM OF LEGAL OPINION OF INTELLECTUAL PROPERTY COUNSEL

THE FINAL OPINION IN DRAFT FORM WILL BE ATTACHED AS EXHIBIT B AT THE

TIME THIS AGREEMENT IS EXECUTED.

Opinion of patent counsel for the Company to be delivered pursuant to
Section 5(e) of the Underwriting Agreement.

[OPINION OF FITZPATRICK, CELLA, HARPER & SCINTO TO BE INSERTED]

1

EXHIBIT C

FORM OF LOCK-UP AGREEMENT

March 1, 2004

Banc of America Securities LLC
SG Cowen Securities Corporation
CIBC World Markets Corp.
ThinkEquity Partners LLC
As Representatives of the Several Underwriters c/o Banc of America Securities LLC
9 West 57th Street
New York, NY 10019

Re: Momenta Pharmaceuticals, Inc. (the "Company")

Ladies and Gentlemen:

The undersigned is an owner of record or beneficially of certain shares of Common Stock of the Company ("Common Stock") or securities convertible into or exchangeable or exercisable for Common Stock. The Company proposes to carry out a public offering of Common Stock (the "Offering") for which you will act as the representatives of the underwriters. The undersigned recognizes that the Offering will be of benefit to the undersigned and will benefit the Company by, among other things, raising additional capital for its operations. The undersigned acknowledges that you and the other underwriters are relying on the representations and agreements of the undersigned contained in this letter in carrying out the Offering and in entering into underwriting arrangements with the Company with respect to the Offering.

In consideration of the foregoing, the undersigned hereby agrees that the undersigned will not, (and will cause any spouse, or immediate family member of the spouse or the undersigned living in the undersigned's household, not to), without the prior written consent of Banc of America Securities LLC and SG Cowen Securities Corporation (which consent may be withheld in their sole discretion), directly or indirectly, sell, offer, contract or grant any option to sell (including, without limitation, any short sale), pledge, transfer, establish an open "put equivalent position" within the meaning of Rule 16a-1(h) under the Securities Exchange Act of 1934, as amended, or otherwise dispose of any shares of Common Stock, options or warrants to acquire shares of Common Stock, or securities exchangeable or exercisable for or convertible into shares of Common Stock currently or hereafter owned either of record or beneficially (as defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended) by the undersigned (or such spouse or family member), or publicly announce an intention to do any of the foregoing, for a period commencing on the date hereof and continuing through the close of trading on the date 180 days after the date of the final prospectus filed by the Company with the Securities and Exchange Commission in connection with the Offering. The foregoing sentence shall not apply to (i) any shares acquired from Banc of America Securities LLC as part of the Offering in connection with the directed share program, (ii) transactions relating to shares of Common Stock or other securities acquired in open market transactions after completion of the Offering,

1

(iii) bona fide gifts not involving a disposition for value, (iv) distributions of shares of Common Stock to partners, members or shareholders of the undersigned, (v) the transfer of any or all of the shares of Common Stock owned by the undersigned, either during his or her lifetime or upon his or her death, by gift, will or intestate succession to the immediate family of the undersigned or to a trust, the beneficiaries of which are exclusively the undersigned and/or a member or members of his or her immediate family, or (vi) dispositions to family limited partnerships or to family limited liability companies for the direct or indirect benefit of, or controlled by, the undersigned or the immediate family of the undersigned; provided, however, that in any such case it shall be a condition to such transfer that the transferee executes and delivers to Banc of America Securities LLC and SG Cowen Securities Corporation an agreement stating that the transferee is receiving and holding the Common Stock subject to the provisions of this letter agreement, and there shall be no further transfer of such Common Stock except in accordance with this letter. The undersigned also agrees and consents to (a) the entry of stop transfer instructions with the Company's transfer agent and registrar against the transfer of, and/or (b) the placement of legends on certificates representing, shares of Common Stock or securities convertible into or exchangeable or exercisable for Common Stock held by the undersigned except in compliance with the foregoing restrictions.

With respect to the Offering only, the undersigned waives any registration rights and related notices with respect to registration under the Securities Act of 1933, as amended, of any Common Stock owned either of record or beneficially by the undersigned, including any rights to receive notice of the Offering.

This agreement shall terminate in the event the Offering is not closed on or before June 30, 2004.

This agreement is irrevocable and will be binding on the undersigned and the respective successors, heirs, personal representatives, and assigns of the undersigned.


Printed Name of Holder

By:

Signature


Printed Name of Person Signing
(and indicate capacity of person signing if signing as custodian, trustee, or on
behalf of an entity)

2

EXHIBIT D

AMENDMENT NO. 1 TO SECOND AMENDED AND RESTATED
INVESTORS' RIGHTS AGREEMENT

[AMENDMENT NO. 1 TO SECOND AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT TO BE INSERTED]

1

Exhibit 4.1

COMMON STOCK COMMON STOCK

[MOMENTA LOGO]

NUMBER SHARES
MO

SEE REVERSE FOR INCORPORATED UNDER THE LAWS CUSIP 60877T 10 0

CERTAIN DEFINITIONS OF THE STATE OF DELAWARE

THIS IS TO CERTIFY THAT

is the owner of

FULLY PAID AND NON-ASSESSABLE SHARES OF THE COMMON STOCK,
PAR VALUE $0.0001 PER SHARE, OF

MOMENTA PHARMACEUTICALS, INC.

transferable on the books of the Corporation by the holder hereof in person or by duly authorized attorney upon surrender of this certificate properly endorsed. This certificate and the shares represented hereby are issued and shall be held subject to all of the provisions of the Certificate of Incorporation of the Corporation and all amendments thereof to all of which the holder by the acceptance hereof assents. This certificate is not valid unless countersigned and registered by the Transfer Agent and Registrar.

WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers.

Dated

/s/ Richard P. Shea       (MOMENTA SEAL)        /s/ Alan L. Crane
     TREASURER                                      PRESIDENT

COUNTERSIGNED AND REGISTERED:
    AMERICAN STOCK TRANSFER & TRUST COMPANY


          (NEW YORK, N.Y.)      TRANSFER AGENT AND REGISTRAR

AUTHORIZED SIGNATURE


MOMENTA PHARMACEUTICALS, INC.

The following abbreviations, when used in the inscription on the face of this Certificate, shall be construed as though they were written out in full according to applicable laws or regulations:

TEN COM -- as tenants in common                   UNIF GIFT MIN ACT- __________ Custodian __________
TEN ENT -- as tenants by the entireties                                (Cust)              (Minor)
 JT TEN -- as joint tenants with right of                            under Uniform Gifts to Minors
           survivorship and not as tenants                           Act _____________

           in common                                                        (State)

Additional abbreviations may also be used though not in the above list.

For Value Received, _________________________ hereby sell, assign, and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
IDENTIFYING NUMBER OF ASSIGNEE



(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)


----------------------------------------------------------------------- Shares of Common Stock represented by the within Certificate, and do hereby irrevocably constitute and appoint

-------------------------------------------------------------------- Attorney to transfer the said shares of Common Stock on the books of the Corporation with full power of substitution in the premises.

Dated _________________________________


NOTICE: THE SIGNATURE(S) TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.

Signature(s) Guaranteed:


THE SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C. RULE 17Ad-15.

KEEP THIS CERTIFICATE IN A SAFE PLACE. IF IT IS LOST, STOLEN, MUTILATED OR DESTROYED, THE CORPORATION WILL REQUIRE A BOND OF INDEMNITY AS A CONDITION TO THE ISSUANCE OF A REPLACEMENT CERTIFICATE.


EXHIBIT 4.3

SECOND AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT

This Second Amended and Restated Investors' Rights Agreement (this "Agreement") dated as of February 27, 2004 (this "Agreement") is made by and among Momenta Pharmaceuticals, Inc., a Delaware corporation (the "Company"); the persons and entities listed on SCHEDULE A (collectively, the "Existing Purchasers"); the persons and entities listed on SCHEDULE B (collectively, the "Additional Purchasers"); the persons and entities listed on SCHEDULE C (collectively, the "Founders"); the Massachusetts Institute of Technology, a Massachusetts corporation ("MIT") with respect to Section 2 herein; and Silicon Valley Bank ("SVB") with respect to Section 3 and Section 5 herein. The Existing Purchasers, the Additional Purchasers, MIT (with respect Section 2) and SVB (with respect to Section 3 and Section 5) are sometimes referred to herein individually as a "Purchaser" and collectively as the "Purchasers."

WHEREAS, the Company, the Existing Purchasers, the Founders, MIT (with respect to Section 2 of the Existing Agreement (as defined herein)) and SVB (with respect to Section 3 and Section 5 of the Existing Agreement) are parties to an Amended and Restated Investors' Rights Agreement dated as of May 9, 2003, as amended (the "Existing Agreement"); and

WHEREAS, the Additional Purchasers are purchasing, concurrently herewith, certain shares of the Company's Series C Convertible Preferred Stock, $0.01 par value per share (the "Series C Preferred Stock," together with the Company's Series A Convertible Preferred Stock, $0.01 par value per share, the Company's Series A Prime Convertible Preferred Stock, $0.01 par value per share, the Company's Series A Double Prime Convertible Preferred Stock, $0.01 par value per share (the "Series A Double Prime Preferred Stock") and the Company's Series B Convertible Preferred Stock, $0.01 par value per share, the "Preferred Stock"), pursuant to a Series C Convertible Preferred Stock Purchase Agreement dated as of the date hereof; and

WHEREAS, MIT owns outstanding shares of the Company's Common Stock, $.0001 par value per share (the "Common Stock") pursuant to an Amended and Restated Exclusive Patent License Agreement dated as of November 15, 2002 by and between the Company and MIT (as amended, the "MIT License Agreement"); and

WHEREAS, SVB is a holder of a warrant (the "SVB Warrant") to purchase shares of the Company's Series A Double Prime Preferred Stock; and

WHEREAS, the Company, the Purchasers, MIT (with respect to Section 2) and SVB (with respect to Section 3 and Section 5) desire to amend and restate the Existing Agreement to provide for certain arrangements with respect to (i) the registration of shares of the capital stock of the Company under the Act (as defined in Section 3 below), and (ii) certain information rights and rights of participation; and

WHEREAS, pursuant to Section 5.5 of the Existing Agreement, such agreement could be amended, modified, terminated or any provision therein waived upon approval of the Company and Purchasers (as defined therein) holding at least 60% of the shares of Preferred Stock (as defined therein) then held by all Purchasers and any such amendment, modification, termination or waiver shall be binding on all parties thereto (the "Requisite Approval"); and


WHEREAS, the Requisite Approval has been received by the Company, and pursuant to Section 5.5 of the Existing Agreement, this Agreement shall be binding upon each of the parties to the Existing Agreement.

NOW, THEREFORE, in consideration of these mutual promises and covenants set forth herein, the parties hereto agree to the terms and conditions set forth below:

1. COVENANTS OF THE COMPANY. The Company covenants and agrees that so long as
(i) any shares of Preferred Stock are outstanding or (ii) the Purchasers in the aggregate hold of record beneficially not less than five percent (5%) of the outstanding Common Stock of the Company, it will perform and observe the following covenants and provisions:

1.1 FINANCIAL STATEMENTS. The Company will maintain books of account in accordance with generally accepted accounting principles applied on a consistent basis, keep full and complete financial records, and furnish the following reports:

(a) to each Purchaser who holds at least 20,000 shares of Preferred Stock, as soon as practicable, but in any event within one hundred twenty (120) days after the end of the Company's 2003 fiscal year and within ninety (90) days after the end of each fiscal year thereafter, an income statement for such fiscal year, a balance sheet of the Company and statement of stockholders' equity as of the end of such year, and a schedule as to the sources and applications of funds for such year, such year-end financial reports to be in reasonable detail, prepared in accordance with generally accepted accounting principles ("GAAP"), and audited and certified by such independent public accountants of nationally recognized standing selected by the Company and approved by the Purchasers;

(b) to Purchasers who holds at least 50,000 shares of Preferred Stock, as soon as practicable, but in any event within thirty (30) days after the end of each month, an unaudited income statement and schedule as to the sources and application of funds and the balance sheet as of the end of such month; and

(c) such other financial information of the Company as the Purchasers may reasonably request, including certificates of the principal financial officer of the Company concerning compliance with the covenants of the Company under this Section 1.1.

1.2 OPERATING PLAN; OTHER REPORTING. The Company will prepare and deliver to each Purchaser on or before the first day of each fiscal year, an annual operating plan (that will include a budget) prepared on a monthly basis and, promptly after preparation, any revisions to such operating plan. In addition, the Company will promptly provide to each Purchaser other customary information and materials, including reports of adverse developments, management letters, communications with stockholders or directors, press releases and registration statements.

1.3 INSPECTION. The Company shall, upon reasonable prior notice to the Company, permit authorized representatives of the Purchasers to visit and inspect any of the properties of the Company including its books of account (and to make copies thereof and take extracts therefrom), and to discuss the affairs, finances and accounts of the Company with its officers,

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administrative employees and independent accountants, all at the expense of the Purchasers and at such reasonable times and as often as may be reasonably requested.

1.4 EMPLOYEE AGREEMENTS. The Company shall require all of its employees and consultants to enter into suitable agreements with provisions governing, among other things, the protection of confidential information, assignment of intellectual property, and competition with the Company.

1.5 RESERVATION OF CONVERSION STOCK. The Company will, upon any increase in the number of shares of Common Stock issuable upon conversion of any series of Preferred Stock, reserve additional shares of Common Stock for issuance upon such conversion, so that the number of shares of Common Stock so reserved will not at any time be less than the number of such shares issuable upon such conversion.

1.6 BOARD MEETINGS. The Company agrees to hold a meeting of its Board of Directors at least four times per year or otherwise as unanimously agreed by the directors.

1.7 TERMINATION OF COVENANTS. The rights set forth in this Article 1 shall terminate and be of no further force or effect upon the earliest to occur of (i) the closing of the Company's initial public offering pursuant to an effective registration statement at a price to the public of at least $10.00 per share (adjusted for stock splits, stock dividends and similar events) resulting in gross proceeds to the Company of at least $15,000,000 (a "Qualified Public Offering"), (ii) the closing of the Company's sale of all or substantially all of its assets or the acquisition of the Company by another entity (other than an entity that controls, or is controlled by, or is under common control with, the Company) by means of merger, consolidation or stock purchase, and (iii) the effective date of the later to occur of (A) the conversion of all of the Series A Convertible Preferred Stock, (B) the conversion of all of the Series A Prime Convertible Preferred Stock, (C) the conversion of all of the Series A Double Prime Convertible Preferred Stock, (D) the conversion of all of the Series B Convertible Preferred Stock and (E) the conversion of all of the Series C Preferred Stock. Notwithstanding the foregoing, in the event that (1) the Pricing Committee of the Company's Board of Directors approves a per share price to the public in connection with the Company's initial public offering at less than $10.00 per share (the "Adjusted IPO Price") (adjusted for stock splits, stock dividends and similar events); (2) the holders of at least 66 2/3% of the shares of Preferred Stock outstanding at that time approve the Adjusted IPO Price; and (3) the Adjusted IPO Price is no less than $7.8463, the rights set forth in this Article 1 shall terminate and be of no further force or effect upon the closing of such initial public offering.

2. RIGHTS.

2.1 DEFINITIONS.

(a) "NEW SECURITIES" shall mean (i) any capital stock of the Company whether or not currently authorized, (ii) all rights, options or warrants to purchase capital stock, and (iii) all securities of any type whatsoever that are, or may become, convertible into capital stock; PROVIDED, HOWEVER, that the term "New Securities" SHALL NOT include (a) the shares of Common Stock issuable upon the conversion of the Preferred Stock; (b) securities issuable upon the

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exercise or conversion of all rights, options or warrants to purchase capital stock of the Company outstanding as of the date hereof; (c) issuances of shares of Common Stock authorized by vote of the Board of Directors of the Company, or options to purchase such shares, that are issued or granted to officers, directors, employees or consultants of the Company; (d) securities offered to the public pursuant to a registration statement filed with the Securities and Exchange Commission; (e) Common Stock, Preferred Stock or other securities issued in connection with any stock split, stock dividend, recapitalization, reclassification or similar event by the Company; (f) securities issued to MIT or persons designated by MIT pursuant to the MIT License Agreement; or (g) securities issued solely in consideration for the acquisition or licensing of technology or in connection with a corporate partnering transaction.

(b) "PURCHASER" shall include, for the purposes of this Section 2,
(i) the general partners, members, officers, or other affiliates of a Purchaser, and (ii) MIT. The term "Purchaser" shall not include any person other than MIT that receives Common Stock from the Company pursuant to the terms of the MIT License Agreement unless a Purchaser subsequently transfers Common Stock to such person. Each Purchaser may apportion its pro rata share among its general partners, members, officers, and other affiliates in such proportions as it deems appropriate.

2.2 PARTICIPATION RIGHT. Each Purchaser shall be entitled to a right to purchase, on a pro rata basis (as defined in this Section 2.2), all or any part of New Securities which the Company may, from time to time, propose to sell and issue, subject to the terms and conditions set forth below. Such Purchaser's pro rata share shall equal a fraction of the New Securities being issued, the numerator of which is the number of shares of Common Stock then held by such Purchaser plus the number of shares of Common Stock issued or issuable upon conversion of the Preferred Stock or other securities then held by such Purchaser, and the denominator of which is the total number of shares of Common Stock then outstanding plus the number of shares of Common Stock issuable upon
(i) conversion of then outstanding Preferred Stock or other convertible securities and (ii) exercise of then outstanding options, rights or warrants (whether or not vested).

2.3 EXERCISE OF RIGHT. In the event the Company intends to issue New Securities, it shall give each Purchaser written notice of such intention, describing the type of New Securities to be issued, the price thereof, and the general terms upon which the Company proposes to effect such issuance and whether or not the failure to participate in such transaction as provided herein would result in a Special Mandatory Conversion, as such term is defined in the Company's certificate of incorporation (the "Sale Notice"). Each Purchaser shall have twenty (20) calendar days from the date of any Sale Notice to agree to purchase all or any part of its pro rata share of such New Securities and all or any part of the pro rata share of any other Purchaser entitled to such rights (to the extent that such other Purchaser(s) do not elect to purchase their full pro rata share), in each case for the price and upon the general terms and conditions specified in the Sale Notice by giving written notice to the Company stating the quantity of New Securities to be so purchased (an "Exercise Notice"); provided, however, that in the event that the transaction described in a Sale Notice involves in whole or in part the payment of non-cash consideration, or the payment of consideration over time, the Purchasers shall have the right to elect, upon exercise of their rights set forth in this Section 2, to pay to the Company in full consideration for

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the New Securities the market price of such securities which shall be the present cash value of the consideration described in the Sale Notice as determined by the Board of Directors of the Company in good faith. If the Purchasers who elect to purchase their full pro rata share also elect to purchase in the aggregate more than 100% of the New Securities, such New Securities shall be sold to such Purchasers in accordance with their respective pro rata share. A failure to provide the Company with written notice setting forth the quantity of New Securities to be purchased by any Purchaser in accordance with this Section 2 shall be deemed to be a waiver by such Purchaser of its right to purchase any portion of its pro rata share of such New Securities.

2.4 CLOSING. The closing of the purchase of New Securities by the Purchasers exercising their rights hereunder ("Participating Purchasers") shall take place at such location, date and time as the parties shall agree but not later than forty (40) calendar days following the delivery of the Sale Notice. At the closing, the Company shall deliver to the Participating Purchasers certificates representing all of the New Securities to be purchased and such other agreements executed by the Company which grant any rights or privileges to the Participating Purchasers as are being granted to the other purchasers in such issuance, and in any event, at the request of the Participating Purchasers, a duly executed certificate reasonably satisfactory to the Participating Purchasers containing a representation and warranty that, upon issuance or transfer of such securities to the Participating Purchasers that the Participating Purchasers will be the legal and beneficial owners of such securities with good title thereto, free and clear of all mortgages, liens, charges, security interests, adverse claims, pledges, encumbrances and demands whatsoever, and that the Company has the absolute right to issue or transfer such securities to the Participating Purchasers without the consent or approval of any other person. At the closing, the Participating Purchasers shall deliver to the Company (i) payment for the New Securities and (ii) such other agreements executed by the other purchasers in such issuance which include representations by such purchasers to the Company or restrict such purchasers' rights with respect to the New Securities, and in any event, at the request of the Company, a duly executed certificate reasonably satisfactory to the Company containing such representations and warranties of the Participating Purchasers with respect to federal and state securities laws. The certificates representing the equity securities may contain a legend stating that they are issued subject to the registration requirements of the Securities Act of 1933, as amended, and applicable state securities laws.

2.5 FAILURE TO EXERCISE RIGHT. In the event the Purchasers fail to exercise the foregoing participation right with respect to any New Securities within the periods specified by Sections 2.3 above, the Company may within one hundred and twenty (120) calendar days after the delivery of the Sale Notice sell any or all of such New Securities not agreed to be purchased by the Purchasers, at a price and upon general terms no more favorable to the purchasers thereof than specified in the Sale Notice. In the event the Company has not sold such New Securities within such 120-day period, the Company shall not thereafter issue or sell any New Securities without first offering such New Securities to the Purchasers in the manner provided in Section 2.3.

2.6 TERMINATION OF RIGHTS. The rights set forth in this Article 2 shall terminate and be on no further force or effect upon the closing of a Qualified Public Offering.

3. REGISTRATION RIGHTS. The Company covenants and agrees as follows:

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3.1 DEFINITIONS. As used in this Section 3, the following terms shall have the following meanings:

(a) "ACT" means the Securities Act of 1933, as amended.

(b) "FORM S-1" means such form under the Act as in effect on the date hereof, or any registration form under the Act subsequently adopted by the SEC which permits the registration of securities under the Act for which no other form is authorized or prescribed.

(c) "FORM S-3" means such form under the Act as in effect on the date hereof or any registration form under the Act subsequently adopted by the SEC which permits inclusion or incorporation of substantial information by reference to other documents filed by the Company with the SEC.

(d) "PREFERRED HOLDER" means (i) a Purchaser and any persons or entities to whom the rights granted under this Section 3 are transferred by the Purchaser and (ii) their successors or assigns as permitted under Section 4 below.

(e) "HOLDERS" means (i) a Preferred Holder and (ii) Ram Sasisekharan, Robert S. Langer, Jr., Ganesh Venkataraman and Alan L. Crane and their Permitted Transferees.

(f) "PERMITTED TRANSFEREE" means, with respect to Ram Sasisekharan, Robert S. Langer, Jr., Ganesh Venkataraman and Alan L. Crane (i) such Holder's spouse, parents and the linear descendants of such Holder's parents (collectively, "family members") to whom Registrable Securities are transferred; and (ii) any trust to which Registrable Securities are transferred (A) in respect of which such Holder serves as trustee, provided that the trust instrument governing such trust shall provide that such Founder, as trustee, shall retain sole and exclusive control over the voting and disposition of such Registrable Securities until the termination of this Agreement or (B) for the benefit solely of such Holder's family members; provided, that no person or entity shall be a Permitted Transferee unless such transferee delivers a written notice to the Company at the time of such transfer stating the name and address of the transferee and identifying the Registrable Securities with respect to which such rights are being assigned.

(g) "1934 ACT" shall mean the Securities Exchange Act of 1934, as amended.

(h) The terms "REGISTER," "REGISTERED," and "REGISTRATION" refer to a registration effected by preparing and filing a registration statement or similar document in compliance with the Act, and the declaration or ordering of effectiveness of such registration statement or document.

(i) "REGISTRABLE SECURITIES" means (i) the Common Stock held by Ram Sasisekharan, Robert S. Langer, Jr., Ganesh Venkataraman and Alan L. Crane and their Permitted Transferees, (ii) the Common Stock issuable or issued upon conversion of the Preferred Stock or upon the conversion of the shares of Series A Double Prime Preferred Stock issuable upon exercise of the SVB Warrant, and
(iii) any Common Stock of the Company issued as (or issuable upon the conversion or exercise of any warrant, right, or other security which is

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issued as) a dividend or other distribution with respect to, or in exchange for or in replacement of, the shares referenced in (i) and (ii) above, excluding in all cases, however, any Registrable Securities sold by a person in a transaction in which the rights under this Section 3 are not properly assigned.

(j) "OUTSTANDING REGISTRABLE SECURITIES" shall mean the number of shares of Common Stock outstanding that are, and the number of shares of Common Stock issuable pursuant to then exercisable or convertible securities which are, Registrable Securities.

(k) "SEC" shall mean the Securities and Exchange Commission.

3.2 DEMAND REGISTRATION.

(a) If the Company shall receive at any time after the earlier of
(1) May 9, 2006, and (2) six months after the Company's initial public offering, a written notice from the Preferred Holders constituting the holder(s) of at least fifty percent (50%) of the Outstanding Registrable Securities then held by Preferred Holders requesting that the Company effect a registration statement under the Act with respect to all or a part of the Registrable Securities held by such Preferred Holder or Preferred Holders, then the Company shall:

(i) within ten (10) days of the receipt thereof, give written notice of such request to all Preferred Holders; and

(ii) effect as soon as practicable, and in any event within ninety (90) days of the receipt of such request, the registration under the Act of all Registrable Securities which the Preferred Holders request to be registered (by notice to the Company within thirty (30) days of the mailing of the notice sent by the Company in accordance with Section 3.2(a)(i)), subject to the limitations of Subsection 3.2(b).

(b) If the Preferred Holders initiating the registration request hereunder ("Initiating Holders") intend to distribute the Registrable Securities covered by their request by means of an underwriting, they shall so advise the Company as a part of their request made pursuant to subsection 3.2(a) and the Company shall include such information in the written notice referred to in subsection 3.2(a). The underwriter will be selected by the Company and shall be reasonably acceptable to a majority in interest of the Initiating Holders. In such event, the right of any Preferred Holder to include Registrable Securities in such registration shall be conditioned upon such Preferred Holder's participation in such underwriting and the inclusion of such Preferred Holder's Registrable Securities in the underwriting (unless otherwise mutually agreed by a majority in interest of the Initiating Holders and such Preferred Holder) to the extent provided herein. All Preferred Holders proposing to distribute their securities through such underwriting shall (together with the Company as provided in subsection 3.5(e)) enter into an underwriting agreement in customary form with the underwriter or underwriters selected for such underwriting. Notwithstanding any other provision of this Section 3.2, if the underwriter advises the Company in writing that marketing factors require a limitation of the number of shares to be underwritten, then the Company shall so advise all Preferred Holders of Registrable Securities which would otherwise be underwritten pursuant hereto, and the number of shares of Registrable Securities that may be included in the underwriting shall be allocated among all

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Preferred Holders thereof, including the Initiating Holders, in proportion (as nearly as practicable) to the amount of Registrable Securities of the Company owned by each Preferred Holder; provided, however, that the number of shares of Registrable Securities to be included in such underwriting shall not be reduced unless all other securities are first entirely excluded from the underwriting.

(c) Notwithstanding the foregoing, if the Company shall furnish to Preferred Holders requesting registration pursuant to this Section 3.2 a certificate signed by the President of the Company stating that in the good faith judgment of the Board of Directors of the Company it would be seriously detrimental to the Company and its stockholders for a registration statement to be filed and it is therefore essential to defer the filing of such registration statement, then the Company shall have the right to defer taking action with respect to such filing for a period of not more than one hundred twenty (120) days after receipt of the request of the Initiating Holders. This deferral right may not be exercised by the Company more than once in any 12-month period.

(d) In addition, the Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to this Section 3.2 after the Company has effected two (2) registrations on Form S-1 pursuant to this Section 3.2 and such registration statements have been declared or ordered effective and the sales of Registrable Securities under such registration statements have closed.

(e) No incidental right under this Section 3.2 shall be construed to limit any registration required under Section 3.3 or Section 3.4 herein.

3.3 "PIGGY-BACK" REGISTRATION.

(a) If (but without any obligation to do so) the Company proposes to register (including for this purpose a registration effected by the Company for stockholders other than the Preferred Holders) any of its stock or other securities under the Act in connection with the public offering of such securities solely for cash, other than (i) a registration relating solely to the sale of securities to participants in a stock plan, (ii) a registration on any form which does not include substantially the same information as would be required to be included in a registration statement covering the sale of the Registrable Securities, (iii) a registration on Form S-4 (or any successor form) relating solely to a transaction pursuant to the SEC's Rule 145, or (iv) a registration relating to the initial public offering of the Company's Common Stock (so long as such registration does not include any shares of Common Stock registered on account of any person other than the Company), the Company shall, at such time, promptly give each Holder written notice of such registration. Upon the written request of each Holder given within twenty (20) days after the mailing of such notice by the Company in accordance with Section 5.4, the Company shall, subject to the provisions of subsection 3.3(b), cause to be registered under the Act all of the Registrable Securities that each such Holder has requested to be registered.

(b) In connection with any offering involving an underwriting of shares of the Company's capital stock, the Company shall not be required under this Section 3.3 to include any of the Holders' securities in such underwriting unless such Holders accept the terms of the underwriting as agreed upon between the Company and the underwriters selected by it (or by

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other persons entitled to select the underwriters), and then only in such quantity as the underwriters determine in their sole discretion will not jeopardize the success of the offering by the Company. If the total amount of securities, including Registrable Securities, requested by stockholders to be included in such offering exceeds the amount of securities to be sold (other than by the Company) that the underwriters determine in their sole discretion is compatible with the success of the offering, then the Company shall be required to include in the offering only that number of such securities, including Registrable Securities, which the underwriters determine in their sole discretion will not jeopardize the success of the offering; provided, however, there shall first be excluded from such registration statement all shares of Common Stock sought to be included therein by (i) any director, consultant, officer, or employee of the Company or any subsidiary of the Company other than Ram Sasisekharan, Robert S. Langer, Jr., Ganesh Venkataraman and Alan L. Crane,
(ii) stockholders exercising any contractual or incidental registration rights subordinate and junior to the rights of the Preferred Holders of Registrable Securities, and (iii) stockholders who do not have contractual registration rights. If after such shares are excluded, the underwriters shall determine in their sole discretion that the number of securities which remain to be included in the offering exceeds the amount of securities to be sold that the underwriters determine is compatible with the success of the offering, then the Registrable Securities to be included, if any, shall be apportioned pro rata among the Holders providing notice of their desire to participate in the offering according to the total amount of securities entitled to be included therein owned by each selling Holder or in such other proportions as shall mutually be agreed to by such Holders. For purposes of the preceding sentence concerning apportionment, for any selling Holder which is a partnership, limited liability company or corporation, the partners, members, retired members, retired partners, and stockholders of such Holder, or the estates and family members of any such partners, members, retired members and retired partners and any trusts for the benefit of any of the foregoing persons shall be deemed to be a single "selling Holder," and any pro rata reduction with respect to such "selling Holder" shall be based upon the aggregate amount of shares carrying registration rights owned by all entities and individuals included in such "selling Holder," as defined in this sentence.

(c) No incidental right under this Section 3.3 shall be construed to limit any registration required under Section 3.2 or Section 3.4 herein.

3.4 FORM S-3 REGISTRATION. In case the Company shall receive from any Preferred Holder or Preferred Holders constituting the holder(s) of at least twenty five percent (25%) of the Outstanding Registrable Securities then held by Preferred Holders a written request or requests that the Company effect a registration on Form S-3 and any related qualification or compliance with respect to all or a part of the Registrable Securities owned by such Preferred Holder or Preferred Holders, the Company agrees:

(a) to promptly give written notice of the proposed registration, and any related qualification or compliance, to all other Holders; and

(b) as soon as practicable after receiving such a request, to effect such registration and all such qualifications and compliances as may be so requested and as would permit or facilitate the sale and distribution of all or such portion of such Preferred Holder's or Preferred Holders' Registrable Securities as are specified in such request, together with all or

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such portion of the Registrable Securities of any other Holder or Holders joining in such request as are specified in a written request given within fifteen (15) days after receipt of such written notice from the Company; provided, however, that the Company shall not be obligated to effect any such registration, qualification, or compliance pursuant to this Section 3.4: (i) if Form S-3 is not available for such offering by the Holders; (ii) if the Holders, together with the holders of any other securities of the Company entitled to inclusion in such registration, propose to sell Registrable Securities and such other securities (if any) at an aggregate price to the public of less than $500,000; (iii) if the Company shall furnish to the Holders a certificate signed by the President of the Company stating that in the good faith judgment of the Board of Directors of the Company, it would be seriously detrimental to the Company and its stockholders for such Form S-3 registration to be effected at such time, in which event the Company shall have the right to defer the filing of the Form S-3 registration statement for a period of not more than sixty (60) days after receipt of the request of the Holder or Holders under this Section 3.4; provided, however, that the Company shall not utilize this right more than once in any eighteen month period; or (iv) until the next calendar year if the Company has effected two (2) registrations on Form S-3 (or its then equivalent) pursuant to this Section 3.4 in a calendar year and such registrations have been declared or ordered effective and the sales of Registrable Securities under such registration statement have closed.

(c) Registrations effected pursuant to this Section 3.4 shall not be counted as demands for registration or registrations effected pursuant to Sections 3.2 or 3.3, respectively.

3.5 OBLIGATIONS OF THE COMPANY. Whenever required under this Section 3 to effect the registration of any Registrable Securities, the Company shall, as expeditiously as reasonably possible (but subject to providing counsel to the Holders with a reasonable opportunity to review and comment on all documents):

(a) Prepare and file with the SEC a registration statement with respect to such Registrable Securities and use its best efforts to cause such registration statement to become effective, and, upon the request of the Holders of a majority of the Registrable Securities registered thereunder, keep such registration statement effective for a period of up to one hundred twenty (120) days or, if earlier, until the distribution contemplated in the Registration Statement has been completed; provided, however, that (i) such 120-day period shall be extended for a period of time equal to the period the Holder refrains from selling any securities included in such registration at the request of an underwriter of Common Stock (or other securities) of the Company and (ii) in the case of any registration of Registrable Securities on Form S-3 which are intended to be offered on a continuous or delayed basis, such 120-day period shall be extended, if necessary, to keep the registration statement effective until all such Registrable Securities are sold; provided, that SEC Rule 415, or any successor rule under the Act, permits an offering on a continuous or delayed basis; and provided further that applicable rules under the Act governing the obligation to file a post-effective amendment permit, in lieu of filing a post-effective amendment which (i) includes any prospectus required by Section 10(a)(3) of the Act or (ii) reflects facts or events representing a material or fundamental change in the information set forth in the registration statement, the incorporation by reference of information required to be included in (i) and
(ii) above to be contained in periodic reports filed pursuant to Section 13 or 15(d) of the 1934 Act in the registration statement.

-10-

(b) Prepare and file with the SEC such amendments and supplements to such registration statement and the prospectus used in connection with such registration statement as may be necessary to comply with the provisions of the Act with respect to the disposition of all securities covered by such registration statement in accordance with each Holder's intended method of disposition.

(c) Furnish to the Holders such numbers of copies of a prospectus, including a preliminary prospectus, in conformity with the requirements of the Act, and such other documents as they may reasonably request in order to facilitate the disposition of Registrable Securities owned by the Holders.

(d) Use its best efforts to register and qualify the securities covered by such registration statement under such other securities or Blue Sky laws of such jurisdictions as shall be reasonably requested by the Holders and any managing underwriter; provided, that the Company shall not be required in connection therewith or as a condition thereto to qualify to do business or to file a general consent to service of process in any such states or jurisdictions, unless the Company is already subject to service in such jurisdiction and except as may be required by the Act.

(e) In the event of any underwritten public offering, enter into and perform its obligations under an underwriting agreement, in usual and customary form, with the managing underwriter of such offering. Each Holder participating in such underwriting shall also enter into and perform its obligations under such an agreement.

(f) Promptly notify each Holder of Registrable Securities covered by such registration statement at any time when a prospectus relating thereto is required to be delivered under the Act as a result of the happening of any event as a result of which the prospectus included in such registration statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein not misleading in the light of the circumstances then existing.

(g) Cause all such Registrable Securities registered pursuant hereunder to be listed on each securities exchange on which similar securities issued by the Company are then listed.

(h) Provide a transfer agent and registrar for all Registrable Securities registered pursuant hereunder and a CUSIP number for all such Registrable Securities, in each case not later than the effective date of such registration.

(i) Furnish, at the request of any Holder requesting registration of Registrable Securities pursuant to this Section 3, on the date that such Registrable Securities are delivered to the underwriters for sale in connection with a registration pursuant to this Section 3, if such securities are being sold through underwriters, copies of (i) the opinion, dated as of such date, of the counsel representing the Company for the purposes of such registration given to the underwriters in such underwritten public offering, which opinion shall be in such form as is reasonably satisfactory to counsel to the underwriters, and
(ii) the letter dated as of such date, from the independent certified public accountants of the Company, to the underwriters in such

-11-

underwritten public offering, addressed to the underwriters, which letter shall be in such form as is reasonably satisfactory to counsel to the underwriters.

3.6 FURNISH INFORMATION. It shall be a condition precedent to the obligations of the Company to take any action pursuant to this Section 3 with respect to the Registrable Securities of any selling Holder that such Holder shall furnish to the Company such information regarding itself, the Registrable Securities held by it, and the intended method of disposition of such securities as shall be required to effect the registration of such Holder's Registrable Securities.

3.7 EXPENSES OF DEMAND AND S-3 REGISTRATIONS. The Company shall pay all expenses other than underwriting discounts and commissions incurred in connection with registrations, filings, or qualifications pursuant to Sections 3.2 and 3.4, including (i) all registration, filing, and qualification fees (including filing fees with the SEC, fees due to the National Association of Securities Dealers and fees due for listing on any stock exchange or for qualifying for quotation on the NASDAQ system); (ii) printers and accounting fees; (iii) fees and disbursements of counsel for the Company; and (iv) the reasonable fees and disbursements of one counsel for the selling Holders; provided, however, that the Company shall not be required to pay for any expenses of any registration proceeding begun pursuant to Section 3.2 or 3.4 if the registration request is subsequently withdrawn at the request of the holders of a majority of the Registrable Securities then held by Preferred Holders to be registered (in which case all Preferred Holders participating in the aborted registration shall bear such expenses), unless the holders of a majority of the Registrable Securities then held by Preferred Holders agree to forfeit their rights to, as applicable, one registration under Section 3.2 (demand registration) or one registration for that calendar year under Section 3.4 (S-3 registration); provided further, however, that if at the time of such withdrawal, the Preferred Holders have either (i) learned of a material adverse change in the condition, business, or prospects of the Company from that known to the Preferred Holders at the time of their request or (ii) been informed by the underwriters of such registration that more than 20% of the Registrable Securities requested for registration shall not be includable therein due to market factors, and in either such case the Preferred Holders have withdrawn the request with reasonable promptness following such disclosure, then the Preferred Holders shall not be required to pay such expenses and shall retain their rights pursuant to Sections 3.2 and 3.4.

3.8 EXPENSES OF "PIGGY-BACK" REGISTRATION. The Company shall pay all expenses incurred in connection with any registration, filing, or qualification of Registrable Securities with respect to the registrations pursuant to Section 3.3 for each Holder, including all registration, filing, and qualification fees, printers and accounting fees relating or apportionable thereto, and the reasonable fees and disbursements of one counsel for the selling Holders selected by them, but excluding underwriting discounts and commissions relating to the Registrable Securities.

3.9 DELAY OF REGISTRATION. No Holder shall have any right to obtain or seek an injunction restraining or otherwise delaying any such registration as the result of any controversy that might arise with respect to the interpretation or implementation of this Section 3.

3.10 INDEMNIFICATION. In the event any Registrable Securities are included in a registration statement under this Section 3:

-12-

(a) To the extent permitted by law, the Company will indemnify and hold harmless each Holder, any underwriter (as defined in the Act) for such Holder, and each person (if any) who controls such Holder or underwriter within the meaning of the Act or the 1934 Act, against any losses, claims, damages or liabilities (joint or several) to which they may become subject under the Act, the 1934 Act, or other federal or state law, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any of the following statements, omissions, or violations (collectively a "Violation"): (i) any untrue statement or alleged untrue statement of a material fact contained in such registration statement, including any preliminary prospectus or final prospectus contained therein or any amendments or supplements thereto, (ii) the omission or alleged omission to state therein a material fact required to be stated therein, or necessary to make the statements therein not misleading, or (iii) any violation or alleged violation by the Company of the Act, the 1934 Act, any state securities law, or any rule or regulation promulgated under the Act, the 1934 Act, or any state securities law; and the Company will pay to each such Holder, underwriter, or controlling person, as incurred, any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability, or action; provided, however, that the indemnity agreement contained in this subsection 3.10(a) shall not apply to amounts paid in settlement of any such loss, claim, damage, liability, or action if such settlement is effected without the consent of the Company (which consent shall not be unreasonably withheld), nor shall the Company be liable in any such case for any such loss, claim, damage, liability, or action to the extent that it arises out of or is based upon a Violation which occurs in reliance upon and in conformity with written information furnished expressly for use in connection with such registration by any such Holder, underwriter or controlling person.

(b) To the extent permitted by law, each selling Holder severally and not jointly will indemnify and hold harmless the Company, each of its directors, each of its officers who has signed the registration statement, each person (if any) who controls the Company within the meaning of the Act, any underwriter, any other Holder selling securities in such registration statement, and any controlling person of any such underwriter or other Holder, against any losses, claims, damages or liabilities (joint or several) to which any of the foregoing persons may become subject, under the Act, the 1934 Act, or other federal or state law, insofar as such losses, claims, damages or liabilities (or actions in respect thereto) arise out of or are based upon any Violation, in each case to the extent (and only to the extent) that such Violation occurs in reliance upon and in conformity with written information furnished by such Holder expressly for use in connection with such registration; and each such Holder will pay, as incurred, any legal or other expenses reasonably incurred by any person intended to be indemnified pursuant to this subsection 3.10(b), in connection with investigating or defending any such loss, claim, damage, liability, or action; provided, however, that the indemnity agreement contained in this subsection 3.10(b) shall not apply to amounts paid in settlement of any such loss, claim, damage, liability, or action if such settlement is effected without the consent of the Holder, which consent shall not be unreasonably withheld; and further provided that in no event shall any indemnity under this subsection 3.10(b) exceed the net proceeds from the offering received by such Holder.

(c) Promptly after receipt by an indemnified party under this
Section 3.10 of notice of the commencement of any action (including any governmental action), such indemnified party will, if a claim in respect thereof is to be made against any indemnifying party

-13-

under this Section 3.10, deliver to the indemnifying party a written notice of the commencement thereof and the indemnifying party shall have the right to participate in, and, to the extent the indemnifying party so desires, jointly with any other indemnifying party similarly noticed, to assume the defense thereof with counsel mutually satisfactory to the parties; provided, however, that an indemnified party (together with all other indemnified parties which may be represented without conflict by one counsel) shall have the right to retain one separate counsel and participate in the defense, with the fees and expenses to be paid by the indemnifying party, if representation of such indemnified party by the counsel retained by the indemnifying party would be inappropriate due to actual or potential differing interests between such indemnified party and any other party represented by such counsel in such proceeding. The failure to deliver written notice to the indemnifying party within a reasonable time of the commencement of any such action, if prejudicial to its ability to defend such action, shall relieve such indemnifying party of any liability to the indemnified party under this Section 3.10, but the omission so to deliver written notice to the indemnifying party will not relieve it of any liability that it may have to any indemnified party otherwise than under this Section 3.10.

(d) If the indemnification provided for in this Section 3.10 is held by a court of competent jurisdiction to be unavailable to an indemnified party with respect to any loss, liability, claim, damage, or expense referred to herein, then the indemnifying party, in lieu of indemnifying such indemnified party hereunder, shall contribute to the amount paid or payable by such indemnified party as a result of such loss, liability, claim, damage, or expense in such proportion as is appropriate to reflect the relative fault of the indemnifying party, on the one hand, and of the indemnified party, on the other, in connection with the statements or omissions that resulted in such loss, liability, claim, damage, or expense as well as any other relevant equitable considerations. The relative fault of the indemnifying party and of the indemnified party shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission to state a material fact relates to information supplied by the indemnifying party or by the indemnified party and the parties' relative intent, knowledge, access to information, and opportunity to correct or prevent such statement or omission.

(e) Notwithstanding the foregoing, to the extent that the provisions relating to indemnification and contribution contained in the underwriting agreement entered into in connection with the underwritten public offering are in conflict with the foregoing provisions, the provisions in the underwriting agreement shall control.

(f) The obligations of the Company and Holders under this Section 3.10 shall survive the completion of any offering of Registrable Securities in a registration statement under this Section 3, and otherwise.

3.11 REPORTS UNDER SECURITIES EXCHANGE ACT OF 1934. With a view to making available to the Holders the benefits of SEC Rule 144 and any other rule or regulation of the SEC that may at any time permit a Holder to sell securities of the Company to the public without registration or pursuant to a registration on Form S-3, the Company agrees to use its best efforts:

(a) to make and keep public information available, as those terms are understood and defined in SEC Rule 144, at all times after ninety (90) days after the effective

-14-

date of the first registration statement filed by the Company for the offering of its securities to the general public;

(b) to take such action, including the voluntary registration of its Common Stock under Section 12 of the 1934 Act, as is necessary to enable the Holders to utilize Form S-3 for the sale of their Registrable Securities, such action to be taken as soon as practicable after the end of the fiscal year in which the first registration statement filed by the Company for the offering of its securities to the general public is declared effective;

(c) to file with the SEC in a timely manner all reports and other documents required of the Company under the Act and the 1934 Act; and

(d) to furnish to any Holder, so long as the Holder owns any Registrable Securities, forthwith upon request (i) a written statement by the Company that it has complied with the reporting requirements of SEC Rule 144 (at any time after ninety (90) days after the effective date of the first registration statement filed by the Company), the Act and the 1934 Act (at any time after it has become subject to such reporting requirements), or that it qualifies as a registrant whose securities may be resold pursuant to Form S-3 (at any time after it so qualifies), (ii) a copy of the most recent annual or quarterly report of the Company and such other reports and documents so filed by the Company, and (iii) such other information as may be reasonably requested in availing any Holder of any rule or regulation of the SEC which permits the selling of any such securities without registration or pursuant to such form.

3.12 "MARKET STAND-OFF" AGREEMENT. Each Holder hereby agrees that, during the period of duration (not to exceed one hundred eighty (180) days) specified by the Company and an underwriter of Common Stock or other securities of the Company, following the effective date of a registration statement of the Company filed under the Act with respect to the Company's initial public offering, such Holder shall not, to the extent requested by the Company and such underwriter, directly or indirectly sell, offer to sell, contract to sell (including any short sale), grant any option to purchase, or otherwise transfer or dispose of (other than to donees who agree to be similarly bound) any securities of the Company held by it at any time during such period except Common Stock included in such registration; provided, however, that all officers and directors of the Company enter into similar agreements.

In order to enforce the foregoing covenant, the Company may impose stop-transfer instructions with respect to the Registrable Securities of a Holder (and the shares or securities of every other person subject to the foregoing restriction) until the end of such period.

Notwithstanding the foregoing, the obligations described in this Section 3.12 shall not apply to a registration relating solely to employee benefit plans on Form S-1 or Form S-8 or similar forms which may be promulgated in the future, or a registration relating solely to a SEC Rule 145 transaction on Form S-4 or similar forms which may be promulgated in the future.

3.13 TERMINATION OF REGISTRATION RIGHTS. No Holder shall be entitled to exercise any right provided for in this Section 3 after five (5) years following the consummation of the sale of securities pursuant to a registration statement filed by the Company under the Act in connection with the initial firm commitment underwritten offering of its securities to the general public.

-15-

4. TRANSFERS OF CERTAIN RIGHTS.

4.1 PERMITTED TRANSFEREES. The rights granted to the Purchasers under Sections 1, 2 and 3 of this Agreement may be transferred or succeeded to only by
(i) any other Purchaser or any general or limited partner, member, officer, or other affiliate of any Purchaser or (ii) any other person or entity that acquires at least five percent (5%) of the Registrable Securities; provided, however, that (A) the Company is given written notice by the transferee at the time of such transfer stating the name and address of the transferee and identifying the securities with respect to which such rights are being assigned, (B) the transferee is not a competitor of the Company as determined in good faith by the Board of Directors, (C) the transferee or assignee agrees in writing to all provisions contained in this Agreement and (D) that such transfer otherwise be effected in accordance with applicable securities laws.

4.2 SUBSEQUENT TRANSFERS. A transferee to whom rights are transferred pursuant to this Section 4 may not again transfer such rights to any other person or entity, other than as provided in Section 4.1 above.

4.3 LEGENDS. Each certificate representing the shares of Preferred Stock shall bear a legend indicating that any holder of the Preferred Stock shall be subject to this Agreement.

5. MISCELLANEOUS.

5.1 SEVERABILITY. The provisions of this Agreement are severable, so that the invalidity or unenforceability of any provision of this Agreement shall not affect the validity or enforceability of any other term or provision of this Agreement, which shall remain in full force and effect.

5.2 SPECIFIC PERFORMANCE. In addition to any and all other remedies that may be available at law in the event of any breach of this Agreement, the Purchasers shall be entitled to specific performance of the agreements and obligations of the parties hereunder and to such other injunctive or other equitable relief as may be granted by a court of competent jurisdiction.

5.3 GOVERNING LAW. This Agreement shall be governed by, and construed and enforced in accordance with, the substantive laws of The Commonwealth of Massachusetts without regard to its principles of conflicts of laws.

5.4 NOTICES. All notices, requests, consents, and other communications under this Agreement shall be in writing and shall be deemed delivered (i) two business days after being send by registered or certified mail, return receipt requested, postage prepaid or (ii) one business day after being sent via a reputable nationwide overnight courier service guaranteeing next business day delivery, in each case to the intended recipient as set forth below:

-16-

(i) If to the Company:

Momenta Pharmaceuticals, Inc. 43 Moulton Street Cambridge, MA 02138 Attn: President Fax: (617) 876-8012

With a copy to:

Hale and Dorr LLP 60 State Street Boston, MA 02109

Attn: Steven D. Singer, Esq.

Fax: (617) 526-5000

(ii) If to an Existing Purchaser, at its address set forth in SCHEDULE A hereto, or at such other address as may have been furnished to the other parties hereto in writing by such Existing Purchaser;

(iii) If to an Additional Purchaser, at its address set forth in SCHEDULE B hereto, or at such other address as may have been furnished to the other parties hereto in writing by such Additional Purchaser; and

(iv) If to a Founder, at its address set forth in SCHEDULE C hereto, or at such other address or addresses as may have been furnished to the other parties hereto in writing by such Founder.

Any party may give any notice, request, consent or other communication under this Agreement using any other means (including, without limitation, personal delivery, messenger service, telecopy, first class mail or electronic mail), but no such notice, request, consent or other communication shall be deemed to have been duly given unless and until it is actually received by the party for whom it is intended. Any party may change the address to which notices, requests, consents or other communications hereunder are to be delivered by giving the other parties notice in the manner set forth in this Section.

5.5 COMPLETE AGREEMENT; AMENDMENTS. This Agreement constitutes the full and complete agreement of the parties hereto with respect to the subject matter hereof, and supersedes all prior agreements and understandings of the parties hereto relating to such subject matter. No amendment, modification, termination or waiver of any provision of this Agreement shall be valid unless in writing and signed (i) by the Company and (ii) Purchasers and their permitted transferees holding at least 60% of the shares of Common Stock issued or issuable upon conversion of the Preferred Stock then held (or deemed held) by all Purchasers and their permitted transferees and any such amendment, modification, termination or waiver shall be binding on all parties hereto.

-17-

5.6 AGGREGATION. All Registrable Securities held or acquired by a Purchaser which is a partnership or a limited liability company shall be aggregated with Registrable Securities held or acquired by any partner or member thereof or by any entity that controls, or is controlled by, or is under common control with, such Purchaser for purposes of determining the availability of any rights under this Agreement, and the exercise of any such rights may be allocated among such affiliated entities in such manner as those affiliated entities shall determine.

5.7 CONSTRUCTION. A reference to a Section or Schedule shall mean a
Section in or Schedule to this Agreement unless otherwise expressly stated. The titles and headings herein are for reference purposes only and shall not in any manner limit the construction of this Agreement which shall be considered as a whole. The words "include," "includes" and "including" when used herein shall be deemed in each case to be followed by the words "without limitation." Whenever the context may require, any pronouns used herein shall include the corresponding masculine, feminine or neuter forms, and the singular form of names and pronouns shall include the plural and vice-versa.

5.8 COUNTERPARTS; FACSIMILE. This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, and all of which together shall constitute one and the same document. This Agreement may be executed by facsimile signatures.

5.9 STOCK SPLITS. All references to numbers of shares in this Agreement shall be appropriately adjusted to reflect any stock dividend, split, combination or other recapitalization of shares by the Company occurring after the date of this Agreement.

5.10 TERMINATION OF EXISTING AGREEMENT. The Existing Agreement is hereby terminated and of no further force or effect.

*****

-18-

IN WITNESS WHEREOF, the parties hereto have executed this Second Amended and Restated Investors' Rights Agreement as of the date first above written.

MOMENTA PHARMACEUTICALS, INC.

By:    /s/ ALAN L. CRANE
   -------------------------------------
   Alan L. Crane
   President and Chief Executive Officer

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


MVM INTERNATIONAL LIFE SCIENCES
FUND NO. 1 L.P.

By: MVM Limited
acting as its General Partner

By:     /s/ C. P. TRINIMAN
   -------------------------------------

MVM LIMITED

By:     /s/ C. P. TRINIMAN
   -------------------------------------


    /s/ STEPHEN REEDERS
----------------------------------------
Stephen Reeders


    /s/ DAVID BRISTER
----------------------------------------
David Brister


    /s/ C. P. TRINIMAN
----------------------------------------
Paul Triniman


    /s/ MARTIN MURPHY
----------------------------------------
Martin Murphy


    /s/ RICHARD LIM
----------------------------------------
Richard Lim


    /s/ THOMAS CASDAGLI
----------------------------------------
Thomas Casdagli

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


POLARIS VENTURE PARTNERS III, L.P.

By: POLARIS VENTURE MANAGEMENT
CO. III, L.L.C., its General Partner

By:     /s/ WILLIAM E. BILODEAU
   ---------------------------------
   William E. Bilodeau
   Attorney-in-fact

POLARIS VENTURE PARTNERS FOUNDERS'
FUND III, L.P.

By: POLARIS VENTURE MANAGEMENT
CO. III, L.L.C., its General Partner

By:     /s/ WILLIAM E. BILODEAU
   ---------------------------------
   William E. Bilodeau
   Attorney-in-fact

POLARIS VENTURE PARTNERS
ENTREPRENEURS' FUND III, L.P.

By: POLARIS VENTURE MANAGEMENT
CO. III, L.L.C., its General Partner

By:     /s/ WILLIAM E. BILODEAU
   ---------------------------------
   William E. Bilodeau
   Attorney-in-fact

CHP II, L.P.

By: CHP II Management, LLC,
its General Partner

By:     /s/ JOHN J. PARK
   ---------------------------------
Name:  John J. Park
Title: Managing Member

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


ATLAS VENTURE FUND V, L.P.
ATLAS VENTURE PARALLEL FUND V-A, C.V.
ATLAS VENTURE PARALLEL FUND V-B, C.V.
ATLAS VENTURE ENTREPRENEURS' FUND
V, L.P.

By: Atlas Venture Associates V, L.P.
their general partner
By: Atlas Venture Associates V, Inc.
its general partner

    /s/ JEANNE LARKIN HENRY
-----------------------------------------
Vice President

ATLAS VENTURE FUND VI, L.P.
ATLAS VENTURE ENTREPRENEURS' FUND
VI, L.P.

By: Atlas Venture Associates VI, L.P.
their general partner
By: Atlas Venture Associates VI, Inc.
its general partner

    /s/ JEANNE LARKIN HENRY
-----------------------------------------
Vice President

ATLAS VENTURE FUND VI GMBH & CO. KG

By: Atlas Venture Associates VI, L.P.
its managing limited partner
By: Atlas Venture Associates VI, Inc.
its general partner

    /s/ JEANNE LARKIN HENRY
-----------------------------------------
Vice President

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


   /s/ ROBERT M.METCALFE
-----------------------------------------
   Robert M. Metcalfe

THE PAUL SCHIMMEL PS PLAN

By:

Name:

Title:

LANSING BROWN INVESTMENTS, LLC

By:    /s/ JOHN L. ZABRISKIE
   -------------------------------------
   Name:   John L. Zabriskie
   Title: President


   /s/ PETER BARTON HUTT
-----------------------------------------
   Peter Barton Hutt

THE CRANE FAMILY IRREVOCABLE TRUST -
2002

By:    /s/ HOWARD CRANE
   -------------------------------------
   Howard Crane, Trustee

BQ VENTURES, LLC

By:    /s/ JEFFREY L. QUILLEN
   -------------------------------------
   Name:  Jeffrey L. Quillen
   Title: Managing Member

WOLF, GREENFIELD & SACKS INVESTMENT
TRUST, LLC

By:

Name:

Title:

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


   /s/ SUSAN WHORISKEY
-----------------------------------------
          Susan Whoriskey

JAMES R. AND MARY W. MCNAB
OPERATING L.P.

By:    /s/ JAMES R. MCNAB
   -------------------------------------
   James R. McNab
   General Partner

MITHRA VENTURES, L.P.

By:MITHRA VENTURES MANAGEMENT,
LLC

By:    /s/ FARAH EBRAHIMI
   -------------------------------------
   Name:  Farah Ebrahimi
   Title:  Managing Director

With respect to Section 2 of the Agreement only:

MASSACHUSETTS INSTITUTE OF
TECHNOLOGY, INC.

By:

Name:

Title:

With respect to Sections 3 and 5 of the Agreement
only:

SILICON VALLEY BANK d/b/a SILICON
VALLEY EAST

By:    /s/ R. BRYAN JADOT
   -------------------------------------
   Name:  R. Bryan Jadot
   Title: Vice President

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


FOUNDERS:

     /s/ RAM SASISEKHARAN                  /s/ ROBERT S. LANGER, JR.
--------------------------------       -----------------------------------
Ram Sasisekharan                       Robert S. Langer, Jr.


     /s/ GANESH VENKATARAMAN              /s/ ALAN L. CRANE
--------------------------------       -----------------------------------
Ganesh Venkataraman                    Alan L. Crane

[Signature Page to Second Amended and Restated Investors' Rights Agreement]


Schedule A

NAMES AND ADDRESSES OF EXISTING PURCHASERS

Polaris Venture Partners III, L.P.
Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0770

Polaris Venture Partners Entrepreneurs' Fund III, L.P. Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0770

Polaris Venture Partners Founders' Fund III, L.P. Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0770

Robert M. Metcalfe
410 Beacon Street
Boston, MA 02115

Robert S. Langer, Jr.
Massachusetts Institute of Technology
Department of Chemical Engineering
45 Carlton Street
Cambridge, MA 02139-4307

The Paul Schimmel PS Plan
TSRI
10550 N. Torrey Pines Road
BCC379
La Jolla, CA 92037
Attn: Paul Schimimel

Lansing Brown Investments, LLC
282 Beacon Street
Boston, MA 02116
Attn: John L. Zabriskie

A-1

Alan L. Crane
Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138

The Crane Family Irrevocable Trust - 2002, Howard R. Crane - Trustee
28 Main Street, East, #1800
Rochester, NY 14614
Fax: (585) 325-6201

Peter Barton Hutt
Covington & Burling
1201 Pennsylvania Avenue, NW
Washington, DC 20004-2401

BQ Ventures, LLC
155 Seaport Boulevard
Boston, MA 02210
Attn: Jeffrey L. Quillen

Wolf, Greenfield & Sacks
Investment Trust, LLC
600 Atlantic Ave.
Boston, MA 02110

Susan Whoriskey
Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138

James R. and Mary W. McNab Operating L.P. c/o James R. McNab Jr.
10 Sylvan Drive, Suite 27
St. Simons Island GA 31522

Massachusetts Institute of Technology (with respect to Section 2 of the Agreement only)
Treasurer's Office
238 Main Street
Cambridge, MA 02142
Attn: Phil Rotner
Fax: (617) 258-6676

A-2

Silicon Valley Bank (with respect to Sections 3 and 5 of the Agreement only) One Newton Executive Park, Suite 200
2221 Washington Street
Newton, MA 02462
Attn: Michael Hanewich

MVM International Life Sciences Fund No. 1 LP 6 Henrietta Street
London WC2E 8PU

MVM Limited
6 Henrietta Street
London WC2E 8PU

Stephen Reeders
6 Henrietta Street
London WC2E 8PU

Paul Triniman
6 Henrietta Street
London WC2E 8PU

David Brister
6 Henrietta Street
London WC2E 8PU

Martin Murphy
6 Henrietta Street
London WC2E 8PU

Richard Lim
6 Henrietta Street
London WC2E 8PU

Thomas Casdagli
6 Henrietta Street
London WC2E 8PU

CHP II, L.P.
c/o Cardinal Partners
221 Nassau Street
Princeton, NJ 08542
Attn: John K. Clarke
Fax: (609) 683-0174

A-3

Atlas Venture Fund V, L.P.
890 Winter Street
Waltham, MA 02451

Atlas Venture Parallel Fund V-A, C.V.
890 Winter Street
Waltham, MA 02451

Atlas Venture Parallel Fund V-B, C.V.
890 Winter Street
Waltham, MA 02451

Atlas Venture Entrepreneurs' Fund V, L.P. 890 Winter Street
Waltham, MA 02451

Atlas Venture Fund VI, L.P.
890 Winter Street
Waltham, MA 02451

Atlas Venture Entrepreneurs' Fund VI, L.P. 890 Winter Street
Waltham, MA 02451

Atlas Venture Fund VI GmbH & Co. KG
890 Winter Street
Waltham, MA 02451

A-4

Schedule B

NAMES AND ADDRESSES OF ADDITIONAL PURCHASERS

Polaris Venture Partners III, L.P.
Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0880

Polaris Venture Partners
Entrepreneurs' Fund III, L.P.
Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0880

Polaris Venture Partners Founders'
Fund III, L.P.
Bay Colony Corporate Center
1000 Winter Street, Suite 3350
Waltham, MA 02154
Attention: Christoph H. Westphal
Fax: (781) 290-0880

MVM International Life Sciences Fund No. 1 LP 6 Henrietta Street
London WC2E 8PU

MVM Limited
6 Henrietta Street
London WC2E 8PU

Stephen Reeders
6 Henrietta Street
London WC2E 8PU

Paul Triniman
6 Henrietta Street
London WC2E 8PU

David Brister
6 Henrietta Street
London WC2E 8PU

B-1

Martin Murphy
6 Henrietta Street
London WC2E 8PU

Richard Lim
6 Henrietta Street
London WC2E 8PU

Thomas Casdagli
6 Henrietta Street
London WC2E 8PU

CHP II, L.P.
c/o Cardinal Partners
221 Nassau Street
Princeton, NJ 08542
Attn: John Clarke
Fax: (609) 683-0174

Atlas Venture Fund V, L.P.
890 Winter Street
Waltham, MA 02451

Atlas Venture Parallel Fund V-A, C.V.
890 Winter Street
Waltham, MA 02451

Atlas Venture Parallel Fund V-B, C.V.
890 Winter Street
Waltham, MA 02451

Atlas Venture Entrepreneurs' Fund V, L.P. 890 Winter Street
Waltham, MA 02451

Atlas Venture Fund VI, L.P.
890 Winter Street
Waltham, MA 02451

Atlas Venture Entrepreneurs' Fund VI, L.P. 890 Winter Street
Waltham, MA 02451

Atlas Venture Fund VI GmbH & Co. KG
890 Winter Street
Waltham, MA 02451

B-2

Mithra Ventures, L.P.
205 Newbury Street, 3rd Floor
Boston, MA 02116
Attn: Sasha Ebrahimi

B-3

Schedule C

NAMES AND ADDRESSES OF FOUNDERS

Alan L. Crane
Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138

Ram Sasisekharan
Massachusetts Institute of Technology
Center for Biomedical Engineering
16-561, 77 Massachusetts Ave.
Cambridge, MA 02139

Robert S. Langer, Jr.
Massachusetts Institute of Technology
Department of Chemical Engineering
45 Carlton Street
Cambridge, MA 02139-4307

Ganesh Venkataraman
Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138

C-1

AMENDMENT NO. 1 TO
SECOND AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT

THIS AMENDMENT NO. 1 TO SECOND AMENDED AND RESTATED INVESTORS' RIGHTS
AGREEMENT (this "Amendment") by and among Momenta Pharmaceuticals, Inc. a Delaware corporation (the "Company"), and the individuals and/or entities set forth on the signature pages hereto (the "Investors") shall be made effective as of June 10, 2004 (the "Effective Date").

WITNESSETH:

WHEREAS, the Company, the Investors and certain other individuals and entities are parties to that certain Second Amended and Restated Investors' Rights Agreement dated as of February 27, 2004 (the "Investors' Rights Agreement");

WHEREAS, pursuant to Section 5.5 of the Investors' Rights Agreement, such agreement can be amended, modified or terminated, or any provision therein can be waived, upon the approval of (i) the Company, and (ii) the Purchasers holding at least sixty percent (60%) of the shares of Common Stock issued or issuable upon conversion of the Preferred Stock then held (or deemed held) by all Purchasers and their permitted transferees;

WHEREAS, the Investors hold the requisite amount of shares of Common Stock issued or issuable upon conversion of the Preferred Stock currently held by all Purchasers and their permitted transferees to amend the Investors' Rights Agreement; and

WHEREAS, the Company and the Investors now desire to amend the Investors' Rights Agreement to reflect mutually agreed upon revised terms in accordance with the provisions of this Amendment.

NOW THEREFORE, in consideration of the promises and mutual covenants contained herein, and intending to be legally bound hereby, the parties hereto agree as follows:

1. DEFINITIONS

Capitalized terms used herein, but not otherwise defined in this Amendment, shall have the meanings ascribed to them in the Investors' Rights Agreement.

2. AMENDMENT

Section 3.2(d) of the Investors' Rights Agreement is hereby amended and restated in its entirety to read as follows:

"In addition, the Company shall not be obligated to effect, or to take any action to effect, any registration pursuant to this Section 3.2 after the Company has effected an aggregate of two (2) registrations, whether on Form S-1, Form S-2 or Form S-3, if available, pursuant to this Section 3.2 and such registration statements have been declared or ordered effective and the sales of Registrable Securities under such registration statements have closed."

3. REFERENCE TO AND EFFECT ON THE INVESTORS' RIGHTS AGREEMENT

(a) On and after the Effective Date, each reference to "this Agreement," "hereunder," "hereof," "herein," or words of like import shall mean and be a reference to the Investors' Rights Agreement as amended hereby. No reference to this Amendment need be made in any instrument or document at any time referring to the Investors' Rights Agreement, a reference to the Investors' Rights Agreement in any of such instrument or document to be deemed to be a reference to the Investors' Rights Agreement as amended hereby.

(b) Except as expressly amended by this Amendment, the provisions of the Investors' Rights Agreement shall remain in full force and effect.

4. GOVERNING LAW

This Amendment shall be governed by, and construed and enforced in accordance with, the substantive laws of The Commonwealth of Massachusetts without regard to its principles of conflicts of laws.

5. COUNTERPARTS

This Amendment may be executed in one or more counterparts, each of which shall be deemed an original, but all of which together shall constitute a single instrument.

*******


IN WITNESS WHEREOF, the undersigned have caused this Amendment No. 1 to be executed and delivered on the date first written above.

COMPANY:

MOMENTA PHARMACEUTICALS, INC.

By: /s/ Alan L. Crane
    -------------------------------------------
    Alan L. Crane
    President and Chief Executive Officer

INVESTORS:

MVM INTERNATIONAL LIFE SCIENCES FUND NO. 1 L.P.

By: MVM Limited
acting as its General Partner

By: /s/ C.P. Triniman
    ------------------------------------

MVM LIMITED

By:


David Brister

                /s/ C.P. Triniman
-----------------------------------------------
                  Paul Triniman


Stephen Reeders

[SIGNATURE PAGE TO AMENDMENT NO. 1 TO INVESTORS' RIGHTS AGREEMENT]


POLARIS VENTURE PARTNERS III, L.P.

By: POLARIS VENTURE MANAGEMENT CO. III, L.L.C.,
its General Partner

By: /s/ Christoph Westphal
    ---------------------------------------
    Christoph Westphal
    Member

POLARIS VENTURE PARTNERS FOUNDERS'
FUND III, L.P.

By: POLARIS VENTURE MANAGEMENT CO. III, L.L.C.,
its General Partner

By: /s/ Christoph Westphal
    ---------------------------------------
    Christoph Westphal
    Member

POLARIS VENTURE PARTNERS ENTREPRENEURS'
FUND III, L.P.

By: POLARIS VENTURE MANAGEMENT CO. III, L.L.C.,
its General Partner

By: /s/ Christoph Westphal
    ---------------------------------------
    Christoph Westphal
    Member

CHP II, L.P.

By: CHP II Management, LLC,
its General Partner

By: /s/ John K. Clarke
    ---------------------------------------
    John K. Clarke
    Managing Member

[SIGNATURE PAGE TO AMENDMENT NO. 1 TO INVESTORS' RIGHTS AGREEMENT]


ATLAS VENTURE FUND V, L.P.
ATLAS VENTURE PARALLEL FUND V-A, C.V.
ATLAS VENTURE PARALLEL FUND V-B, C.V.
ATLAS VENTURE ENTREPRENEURS' FUND V, L.P.

By: Atlas Venture Associates V, L.P.
their general partner

By: Atlas Venture Associates V, Inc.
its general partner

/s/ Jeanne Larkin Henry
----------------------------------------
Vice President

ATLAS VENTURE FUND VI, L.P.
ATLAS VENTURE ENTREPRENEURS' FUND VI, L.P.

By: Atlas Venture Associates VI, L.P.
their general partner

By: Atlas Venture Associates VI, Inc.
its general partner

/s/ Jeanne Larkin Henry
----------------------------------------
Vice President

ATLAS VENTURE FUND VI GMBH & CO. KG

By: Atlas Venture Associates VI, L.P.
its managing limited partner

By: Atlas Venture Associates VI, Inc.
its general partner

/s/ Jeanne Larkin Henry
----------------------------------------
Vice President

MITHRA VENTURES, L.P.

By: MITHRA VENTURES MANAGEMENT, LLC

By: /s/ Nina Ross
    -----------------------------------
    Name:  Nina Ross
    Title: Managing Director

[SIGNATURE PAGE TO AMENDMENT NO. 1 TO INVESTORS' RIGHTS AGREEMENT]


THE PAUL SCHIMMEL PS PLAN

By:

Name:

Title:

LANSING BROWN INVESTMENTS, LLC

By: /s/ John L. Zabriske
    -----------------------------------
    Name:  John L. Zabriske
    Title: President

        /s/ Peter Barton Hutt
---------------------------------------
         Peter Barton Hutt

THE CRANE FAMILY IRREVOCABLE TRUST - 2002

By: /s/ Howard Crane
    -----------------------------------
      Howard Crane, Trustee

BQ VENTURES, LLC

By:

Name:

Title:

WOLF, GREENFIELD & SACKS INVESTMENT TRUST, LLC

By:

Name:

Title:


Susan Whoriskey

James R. and Mary W. McNab Operating L.P.

By:

James R. McNab General Partner

[SIGNATURE PAGE TO AMENDMENT NO. 1 TO INVESTORS' RIGHTS AGREEMENT]


Exhibit 5.1

WILMER CUTLER PICKERING HALE AND DORR LLP

60 State Street
Boston, MA 02109

+1 617 526 6000
+1 617 526 5000 fax wilmerhale.com

June 15, 2004

Momenta Pharmaceuticals, Inc.
43 Moulton Street
Cambridge, MA 02138

Re: Registration Statement on Form S-1

Ladies and Gentlemen:

This opinion is furnished to you in connection with a Registration Statement on Form S-1 (File No. 333-113522) (the "Registration Statement") filed with the Securities and Exchange Commission (the "Commission") under the Securities Act of 1933, as amended (the "Securities Act"), for the registration of 6,152,500 shares of Common Stock, $0.0001 par value per share (the "Shares"), of Momenta Pharmaceuticals, Inc., a Delaware corporation (the "Company"), including 802,500 Shares issuable upon exercise of an over-allotment option granted by the Company.

The Shares are to be sold by the Company pursuant to an underwriting agreement (the "Underwriting Agreement") to be entered into by and among the Company and SG Cowen & Co., LLC, Banc of America Securities LLC, CIBC World Markets Corp. and ThinkEquity Partners LLC, as representatives of the several underwriters named in the Underwriting Agreement, the form of which has been filed as Exhibit 1 to the Registration Statement.

We are acting as counsel for the Company in connection with the issue and sale by the Company of the Shares. We have examined signed copies of the Registration Statement as filed with the Commission. We have also examined and relied upon the Underwriting Agreement, minutes of meetings of the stockholders and the Board of Directors of the Company as provided to us by the Company, stock record books of the Company as provided to us by the Company, the Certificate of Incorporation and By-Laws of the Company, each as restated and/or amended to date, and such other documents as we have deemed necessary for purposes of rendering the opinions hereinafter set forth.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as copies, the authenticity of the originals of such latter documents and the legal competence of all signatories to such documents.

BALTIMORE BERLIN BOSTON BRUSSELS LONDON MUNICH

NEW YORK NORTHERN VIRGINIA OXFORD PRINCETON WALTHAM WASHINGTON

WILMER CUTLER PICKERING HALE AND DORR LLP IS A DELAWARE LIMITED LIABILITY
PARTNERSHIP.


Momenta Pharmaceuticals, Inc.
June 15, 2004

Page 2

We express no opinion herein as to the laws of any state or jurisdiction other than the state laws of the Commonwealth of Massachusetts, the General Corporation Law of the State of Delaware and the federal laws of the United States of America.

Based upon and subject to the foregoing, we are of the opinion that the Shares have been duly authorized for issuance and, when the Shares are issued and paid for in accordance with the terms and conditions of the Underwriting Agreement, the Shares will be validly issued, fully paid and nonassessable.

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters. This opinion is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein.

We hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our name therein and in the related Prospectus under the caption "Legal Matters." In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

Very truly yours,

/s/ WILMER CUTLER PICKERING HALE AND DORR LLP

WILMER CUTLER PICKERING HALE AND DORR LLP



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Exhibit 23.1


CONSENT OF INDEPENDENT AUDITORS

        We consent to the reference to our firm under the caption "Experts" and to the use of our report dated February 27, 2004 (except for the first four paragraphs of Note 16, as to which the date is March 8, 2004), in Amendment No. 4 to the Registration Statement (Form S-1 No. 333-113522) and related Prospectus of Momenta Pharmaceuticals, Inc.

  /s/ Ernst & Young LLP

Boston, Massachusetts
June 11, 2004




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CONSENT OF INDEPENDENT AUDITORS