RISK FACTORS

Investing in our common stock involves a high degree of risk. You should consider carefully the risks described below, together with the other information in this prospectus (including our financial statements and the related notes) before investing in our common stock. If any of the following risks actually occur, our business, operating results or financial condition could be materially adversely affected. This could cause the market price of our common stock to decline, and could cause you to lose all or part of your investment.

Risks Related to our Business

We are dependent on the success of our lead product candidate, oritavancin, and we cannot give any assurance that it will receive regulatory approval, which is necessary before it can be commercialized.

Our near-term prospects are substantially dependent on our ability to submit an NDA on a timely basis for our lead product candidate, oritavancin, obtain FDA approval to market oritavancin and successfully commercialize this product. We currently plan to submit an NDA to the FDA in the first quarter of 2008 seeking approval to commercialize oritavancin for the treatment of cSSSI. We will not be able to commercialize oritavancin prior to obtaining FDA approval. Even if we submit an NDA to the FDA on our currently anticipated timeline, we would not expect to receive FDA approval and be able to commercialize this product for at least twelve months after the date of this offering, at the earliest. We cannot assure you that our timeline for filing an NDA for oritavancin will not be delayed, or that we will be able to obtain FDA approval for this product. If we are not able to commercialize oritavancin for cSSSI or for any other indications, we will not be able to generate product revenues in the foreseeable future, or at all. Oritavancin is the only one of our product candidates for which clinical trials have been conducted, and we do not expect to advance any other product candidates into clinical trials until 2009, if at all.

We have limited experience conducting clinical trials, and no prior experience in submitting an NDA to the FDA seeking regulatory approval to commercialize a drug. The two Phase 3 clinical trials that we intend to use in support of our NDA for oritavancin for cSSSI were conducted by our predecessors in the development of this drug. These two Phase 3 trials were designed and conducted as non-inferiority studies in which oritavancin was compared with vancomycin followed by cephalexin, an approved treatment for patients who have serious gram-positive infections. The goal of a non-inferiority study, such as those conducted with respect to oritavancin, is to show that a product candidate is not less effective than the approved treatment.

It is possible that the FDA may refuse to accept our NDA for substantive review or may conclude after review of our data that our application is insufficient to allow approval of oritavancin. If the FDA does not accept or approve our NDA, it may require that we conduct additional clinical, pre-clinical or manufacturing validation studies and submit that data before it will reconsider our application. Depending on the extent of these or any other FDA required studies, approval of any NDA or application that we submit may be delayed by several years, or may require us to expend more resources than we have available. In addition, increased scrutiny by the United States Congress of the FDA’s approval process may significantly delay or prevent regulatory approval, as well as impose more stringent product labeling and post-marketing testing requirements on pharmaceutical products generally, and particularly in our areas of focus. Any delay in obtaining, or an inability to obtain, regulatory approvals would prevent us from commercializing oritavancin or any of our other product candidates, generating revenues, and achieving and sustaining profitability. It is also possible that additional studies, if performed and completed, may not be considered sufficient by the FDA to approve our application. If any of these outcomes occur, we may be forced to abandon our application for approval of oritavancin, which would materially adversely affect our business and could potentially cause us to cease operations.

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We may experience significant delays in the launch of oritavancin for commercialization, which would delay our generation of revenues.

We could experience significant delays in the commercial launch of oritavancin due to many factors, including:

Any one or a combination of these events could significantly delay, or even prevent, our ability to commercialize oritavancin. If we are not successful in commercializing oritavancin, or if we are significantly delayed in doing so, our business, operating results and financial condition will be materially adversely affected.

Recent FDA and Congressional actions have led to uncertainty as to the standards for obtaining FDA approval of new drugs generally and new antibiotics specifically, and we cannot assure you that the FDA will not either require us to meet new standards in order to obtain approval for commercial sale of oritavancin or require us to demonstrate to the FDA’s satisfaction why trial results under superseded standards are adequate.

In 2006, the FDA, for certain types of antibiotics for certain less serious, typically self-resolving infections, refused to accept successfully completed non-inferiority studies as the basis for approval. Instead, for some

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antibiotic products or trials involving comparator antibiotics, the FDA required placebo-controlled trials demonstrating the superiority of a drug candidate to placebo before considering approval. Conducting placebo-controlled trials for antibiotics can be time-consuming, expensive, and difficult to complete. Institutional review boards may not grant approval for placebo-controlled trials because of ethical concerns about denying some participating patients access to any antibiotic therapy during the course of the trial. Even if institutional review board approval is obtained, it may be difficult to enroll patients in placebo-controlled trials, particularly for infections that are serious and, if left untreated, life-threatening, because certain patients would not receive antibiotic therapy. In addition, the FDA has not indicated whether all antibiotics would require placebo- controlled superiority studies for FDA approval. This lack of guidance creates uncertainties about the standards for approval of antibiotics in the United States.

Moreover, recent events, including complications arising from FDA-approved drugs, have raised questions about the safety of marketed drugs and may result in new legislation by the United States Congress and increased caution by the FDA and comparable foreign regulatory authorities in reviewing new drugs based on safety, efficacy or other regulatory approvals. In particular, non-inferiority studies have come under scrutiny from Congress, in part because of a congressional investigation as to the safety of Ketek, an antibiotic approved by the FDA on the basis of non-inferiority studies. Certain key members of Congress have asked the United States Government Accountability Office, an independent, non-partisan arm of Congress, to investigate the FDA’s reliance on non-inferiority studies as a basis for approval. It is possible that members of Congress may draft and introduce, and that Congress may pass, legislation that could significantly change the FDA’s approval process for antibiotics. If this were to happen, the path to regulatory approval for oritavancin might be significantly delayed.

We believe, based on our communications to date with the FDA, that the FDA will not require placebo-controlled studies to support approval of an NDA for oritavancin for cSSSI. In particular, the FDA has acknowledged that clinical trials relying on a non-inferiority trial design, like the two Phase 3 clinical trials conducted by our predecessors on oritavancin for cSSSI, are the appropriate type of trial design for the study of the safety and efficacy of oritavancin for the treatment of a serious and, if left untreated, life-threatening infection like cSSSI. However, though we have not been asked to date to do so, we cannot assure you that the FDA will not require us to perform additional clinical trials to demonstrate the non-inferiority or superiority of oritavancin as compared either to placebo or to previously approved treatments like vancomycin. In addition, we cannot assure you that the FDA will, when reviewing our NDA submission, consider the results of the two Phase 3 clinical trials of oritavancin sufficient.

If we cannot justify to the FDA the 15% non-inferiority margin used in the first Phase 3 study of oritavancin with respect to oritavancin’s benefit over placebo and its non-inferiority to vancomycin and other approved antibiotics, the FDA may not approve oritavancin without an additional Phase 3 study or at all.

The first of the two Phase 3 studies of oritavancin for cSSSI conducted by our predecessors was designed to demonstrate non-inferiority on primary endpoint with a delta, or difference, in cure rate of 15% between oritavancin and the comparator (a combination of vancomycin followed by cephalexin). A 15% delta was appropriate for this non-inferiority trial at the time the FDA reviewed the protocol design of this Phase 3 trial, which commenced in 1999. The results of this first Phase 3 trial demonstrated oritavancin’s efficacy at the lower bound using a 95% confidence interval to be -14.8%, which was within the non-inferiority delta as compared to the control arm. Although the trial results were within the then accepted 15% non-inferiority delta for this particular clinical trial, new International Conference on Harmonization, or ICH, guidelines now request the sponsor to provide a reliable estimate of the placebo-adjusted cure rate of the control treatment (in our case, vancomycin) in a population similar to that enrolled in the trial, before selecting the non-inferiority margin. In pre-NDA meetings, the FDA has noted that a new retrospective justification by us of a 15% non-inferiority margin, based on the new ICH guidelines, will be a critical element in its review of this Phase 3 clinical trial. We are in the process of compiling materials and information in an effort to apply the new ICH guidelines to support

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retrospectively the 15% non-inferiority margin. If we are unable to identify sufficient materials and information to justify the 15% non-inferiority margin, or if the FDA does not find the materials and information we submit to be persuasive and sufficient to support approval of an NDA or find our justification for the use of a 15% non-inferiority delta compelling, we may be unable to obtain FDA approval for oritavancin without additional clinical trials or at all. Any requirement of the FDA that we conduct an additional Phase 3 study of oritavancin would entail substantial expense and delay, and we cannot assure you in such a case that oritavancin would ever receive FDA approval.

If we are unable to discover, develop or acquire product candidates that are safe and effective, our business will be adversely affected.

We have never commercialized any of our product candidates. Further, we are uncertain whether any of our product candidates will prove effective and safe in humans or meet applicable regulatory standards. Companies in the biotechnology and pharmaceutical industries, including companies with greater experience in pre-clinical testing and clinical trials than we have, have suffered significant setbacks in advanced clinical trials, even after demonstrating promising results in earlier trials. The risk of failure for all of our product candidates is high. The data supporting our drug discovery and development programs is derived solely from laboratory experiments, pre-clinical studies and clinical studies. Further, we have limited experience conducting clinical trials, and the two Phase 3 clinical trials that we will use in support of the NDA we intend to submit to the FDA later this year for oritavancin for cSSSI were conducted by our predecessors in the development of oritavancin. There can be no assurance that the Phase 3 clinical trials conducted by our predecessors included a sufficiently large population of patients to demonstrate safety and efficacy sufficient for the FDA to approve the dosage levels that will be included in the product label within our NDA submission.

We anticipate performing further clinical trials of oritavancin over the next several years in an effort to establish its efficacy in other indications. Beyond oritavancin, our other compounds remain in the lead identification, lead optimization, pre-clinical testing and early clinical testing stages. It is, therefore, impossible to predict when or if any of our compounds and product candidates will prove effective or safe in humans or will receive regulatory approval.

In addition to internal development, an element of our strategy is to seek to in-license other innovative antibiotic product candidates from third parties. Our success in executing on this strategy depends upon our ability to identify, select and acquire the right product candidates and products on terms that are acceptable to us. Any product candidate we identify, license or acquire may require additional development efforts prior to commercial sale, including extensive clinical testing and approval by the FDA and applicable foreign regulatory authorities.

If we are unable to discover, develop or acquire medicines that are effective and safe in humans, our business will fail.

The development and testing of our product candidates are subject to extensive regulation, which can be costly and time consuming. Any of our product candidates may encounter unanticipated delays or suffer significant setbacks or fail in later clinical studies.

Product candidates that have shown promising results in early pre-clinical or clinical studies may subsequently suffer significant setbacks or fail in later clinical studies. Clinical studies involving our product candidates may reveal that those candidates are ineffective, inferior to existing approved medicines, unacceptably toxic or have other unacceptable side effects. Negative or inconclusive results from or adverse medical events during a clinical trial could cause the clinical trial to be repeated or a program to be terminated, even if other studies or trials relating to the program are successful.

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Clinical testing is expensive, can take many years to complete and its outcome is uncertain. Failure can occur at any time during the clinical trial process. Additionally, the time required to obtain approval by the FDA is unpredictable, but typically takes many years following the commencement of clinical trials. If our clinical studies are substantially delayed or fail to prove the safety and effectiveness of our product candidates, we may not receive regulatory approval of any of our product candidates, and our business, operating results and financial condition will be materially harmed.

Further, we must conduct our clinical trials under protocols that are acceptable to regulatory authorities and to the committees responsible for clinical studies at the hospital sites at which these studies are conducted. We may experience delays in preparing protocols or receiving approval for them that may delay either or both of the start and finish of our clinical trials. In addition, we may receive feedback from regulatory authorities or results from earlier stage clinical studies that require modifications or delays in planned later stage clinical trials or that cause a termination or suspension of our drug development efforts. If we were to encounter any of these types of delays or suspensions, our drug development costs would likely increase and the timeline for our receipt of regulatory approvals would likely be delayed.

We may be required to suspend or discontinue clinical trials due to the occurrence of unacceptable side effects or other safety risks that could preclude or delay approval of our product candidates.

Our clinical trials may be suspended at any time for a number of reasons. We may voluntarily suspend or terminate our clinical trials if at any time we believe that they present an unacceptable risk to participants. In addition, regulatory agencies may order the temporary or permanent discontinuation of our clinical trials at any time if they believe that the clinical trials are not being conducted in accordance with applicable regulatory requirements or that they present an unacceptable safety risk to participants.

Many antibiotics produce significant side effects, including severe allergic reaction, decreased blood pressure, suppression of the bone marrow, inflammation, swelling at the site of injection, muscle toxicity, optic and peripheral neuropathies and headaches. In clinical trials performed to date, side effects of oritavancin have included headache, nausea, vomiting, constipation, phlebitis, dizziness, insomnia, diarrhea and histamine reactions such as flushing, wheezing and itching. In addition, future clinical trials could reveal other side effects. The incidence of these or other side effects could cause us to interrupt, delay or halt future clinical trials of our product candidates and could result in the FDA or other regulatory authorities stopping further development of or denying approval of our product candidates for any or all targeted indications. Even if we believe our product candidates are safe, our data is subject to review by the FDA and comparable foreign regulatory authorities, which may disagree with our conclusions. Moreover, though we have clinical trial insurance, we could be subject to significant liability if any volunteer or patient suffers, or appears to suffer, adverse health effects as a result of participating in one of our clinical trials.

In 2004, InterMune, then the developer of oritavancin, requested a voluntary, self-imposed clinical hold on oritavancin prior to completion of two Phase 1 studies (OCSI-007 and OCSI-008) that were performed to evaluate drug-drug interaction and QT interval prolongation. InterMune requested this self-imposed clinical hold in part due to the observance of phlebitis at the infusion site judged to be unexpectedly greater in incidence and severity than anticipated. We have, since our acquisition of the rights to oritavancin from InterMune in December 2005, reexamined the data from all of the clinical trials with oritavancin and determined that the incidence of phlebitis in the clinical trials of oritavancin for cSSSI was not substantially higher than found with treatment with vancomycin or other glycopeptides. Further, we submitted our assessment of this data to the FDA and, at a January 2007 pre-NDA meeting, the FDA accepted our assessment and agreed to lift the voluntary clinical hold on oritavancin. Although we believe that we have satisfactorily resolved this safety concern, we cannot assure you that this historic safety concern or any other safety concerns will not result in significant delays in obtaining regulatory approval of our NDA or more stringent product labeling requirements for the cSSSI indication.

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The regulatory approval process for our product candidates is complex and costly. If oritavancin or the other product candidates that we develop are not approved by regulatory agencies, including the FDA, we will be unable to commercialize them.

Before we can launch our product candidates for commercial distribution, we must provide the FDA and similar foreign regulatory authorities with data from pre-clinical and clinical studies that demonstrates that our product candidates are safe and effective for a defined indication. Our product candidates may face delays in receiving regulatory approval or may fail to receive regulatory approval at all for many reasons, including the following:

We will not obtain regulatory approval for a product candidate in the United States unless and until the FDA approves an NDA. In order to market our medicines outside of the United States, we must obtain separate regulatory approvals in each country unless, in the case of the EU, we follow the centralized approval process. The approval procedure varies among countries and can involve additional testing. Further, the time required to obtain approval from foreign regulatory authorities may differ from that required to obtain FDA approval. 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. Satisfaction of these and other regulatory requirements is costly, time consuming, uncertain and subject to unanticipated delays. We have not yet submitted an NDA to the FDA or made a comparable submission in any foreign country for any of our product candidates, including oritavancin.

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The FDA or comparable foreign regulatory authorities might decide that our data is insufficient for approval and require additional clinical trials or other studies. Additionally, recent events have raised questions about the safety of marketed drugs and may result in increased cautiousness by the FDA and/or comparable foreign regulatory authorities in reviewing new drugs based on safety, efficacy or other regulatory considerations. Further, the FDA and comparable foreign regulatory authorities may decelerate regulatory approvals for new drug candidates and impose more stringent product labeling requirements in an effort to ensure that approved drugs are safe and efficacious. Any delay in obtaining, or any inability to obtain, applicable regulatory approvals would prevent us from commercializing our product candidates. Further, even if we do receive regulatory approval to market a commercial product, that approval may be subject to limitations on the indicated uses for the approved drug product. It is possible that none of our existing product candidates or any product candidates we may seek to develop in the future will ever obtain the necessary regulatory approvals for commercialization.

Oritavancin may not be accepted by physicians, patients, third party payors, or the medical community in general.

Even if oritavancin is approved by the relevant regulatory agencies, the commercial success of oritavancin will depend upon its acceptance by physicians, patients, third party payors and the medical community in general. If approved, oritavancin will compete with vancomycin, a relatively inexpensive generic drug that is manufactured by a variety of companies, a number of existing antibiotics manufactured and marketed by major pharmaceutical companies and others, including linezolid (marketed by Pfizer as Zyvox) and daptomycin (marketed by Cubist as Cubicin), and potentially new antibiotics that are not yet on the market. Even if the medical community accepts that oritavancin is safe and efficacious for its approved indications, physicians may not immediately be receptive to the use of oritavancin or may be slow to adopt it as an accepted treatment for gram-positive infections. In the United States and elsewhere, sales of pharmaceutical products depend in significant part on the availability of coverage and reimbursement to providers and the consumer from third-party payors, such as government and private insurance plans. These third-party payors are increasingly challenging and negotiating the prices charged for medical products and services based on their degree of value to the patient. If not added to hospital and managed care organization formularies, oritavancin will not be available for prescription by treating physicians.

If we are unable to demonstrate to physicians that, based on experience, clinical data, side-effect profiles and other factors, oritavancin is preferable to vancomycin and other existing or subsequently-developed anti-infective drugs, we may never generate meaningful revenue from oritavancin. The degree of market acceptance of oritavancin depends on a number of factors, including, but not limited to:

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We have incurred operating losses in each year since our inception and expect to continue to incur substantial losses for the foreseeable future.

We have been engaged in discovering and developing compounds and product candidates since May 1997. We only acquired worldwide rights to oritavancin from InterMune in December 2005. To date, we have not generated any product sales revenue from oritavancin or any drug product candidate, and we may never generate revenue from selling pharmaceutical products. Further, even if we are able to commercialize oritavancin or any other product candidate, there can be no assurance that we will ever achieve profitability. As of March 31, 2007, we had a deficit accumulated during the development stage of approximately $82.3 million, restated.

Assuming we obtain FDA approval, we expect that our expenses will increase as we prepare for the commercial launch of oritavancin and as we conduct further clinical trials on oritavancin for other indications. We also expect that our research and development expenses will continue to increase as we continue to initiate new discovery programs and expand our development programs. As a result, we expect to continue to incur substantial losses for the foreseeable future, and these losses may be increasing. We are uncertain when or if we will be able to achieve or sustain profitability. Failure to become and remain profitable would adversely affect the price of our common stock and our ability to raise capital and continue operations.

If we are unable to generate revenues from any product candidates, including oritavancin, or if we are unable to cost-effectively acquire other drug candidates or drug products, our ability to create long-term shareholder value may be limited.

We have no drug products that have been approved by the FDA. Our product candidate closest to possible commercialization is oritavancin, for which we have not yet filed an NDA and for which we must still seek and receive regulatory approval prior to commercial launch. We do not have any product candidates that will generate revenues in the near term. We note that most drug candidates never make it to the clinical development stage and even those that do make it into clinical development have only a small chance of gaining regulatory approval and becoming a drug product. If we are unable to commercialize any of our current or future drug candidates, including oritavancin, or to acquire any marketable drug products, our ability to create long-term shareholder value will be limited.

In the future, we may seek out opportunities to partner with other companies to acquire rights to other drug candidates or drug products, but there is no guarantee that we will be successful in these efforts. The market to acquire rights to promising drug candidates and drug products is highly competitive, and we would be competing with companies that have significantly more resources and experience than we have. In addition, proposing, negotiating, completing and integrating an economically viable drug product acquisition or license is a lengthy and complex process. We may not be able to acquire or license the rights to additional product candidates and approved products on terms that we find acceptable, or at all.

We face significant competition from other biotechnology and pharmaceutical companies and our operating results will suffer if we fail to compete effectively.

The biotechnology and pharmaceutical industries are intensely competitive. We have competitors both in the United States and internationally, including major multinational pharmaceutical companies, biotechnology companies and universities and other research institutions. Many of our competitors have greater financial and

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other resources, such as larger research and development staff and more experienced marketing and manufacturing organizations. Our competitors may succeed in developing, acquiring or licensing on an exclusive basis technologies and drug products that are more effective or less costly than oritavancin or any drug candidate that we are currently developing or that we may develop, which could render our technology obsolete and noncompetitive.

The competition in the market for therapeutic products that address infectious diseases is intense. Oritavancin faces competition in the United States from commercially available drugs such as vancomycin, marketed generically by Abbott, Shionogi & Co., Ltd., and others; daptomycin, marketed by Cubist Pharmaceuticals, Inc. as Cubicin; and linezolid, marketed by Pfizer, Inc. as Zyvox. In particular, vancomycin has been a widely used and well known antibiotic for over 40 years and is sold in a relatively inexpensive generic form. Vancomycin, daptomycin and linezolid are all approved treatments for serious gram positive infections such as cSSSI. Further, daptomycin is an approved treatment for bacteremia, linezolid is an approved treatment for nosocomial pneumonia and vancomycin is an approved treatment for both bacteremia and pneumonia.

In addition, Pfizer is seeking FDA approval to market dalbavancin (under the name Zeven ^® ) in the United States, which, according to filings made by Pfizer with the Securities and Exchange Commission, could occur during 2007, and, according to filings made by Theravance with the Securities and Exchange Commission, Theravance is seeking FDA approval to market telavancin in the United States and submitted an NDA for telavancin in 2006. Other drug candidates in development include ceftobiprole (developed by Johnson & Johnson) and iclaprim (developed by Arpida Ltd.), which, if approved, would compete in the intravenous antibiotic market and would target indications such as cSSSI. In addition, oritavancin may face competition from drug candidates currently in clinical development and drug candidates that could receive regulatory approval before oritavancin in countries outside the United States and the European Union.

Our ability to compete successfully will depend largely on our ability to leverage our experience in drug discovery and development to:

Any new medicine that competes with a generic market leading medicine must demonstrate compelling advantages in efficacy, convenience, tolerability and/or safety in order to overcome severe price competition and be commercially successful. If approved, oritavancin must demonstrate these advantages, as it will compete with vancomycin, a relatively inexpensive generic drug that is manufactured by a number of companies, and a number of existing antibiotics marketed by major pharmaceutical companies. We will not achieve our business plan if the acceptance of oritavancin is inhibited by price competition or the reluctance of physicians to switch from existing drug products to oritavancin or if physicians switch to other new drug products, or choose to reserve oritavancin for use in limited circumstances. The inability to compete with existing drug products or subsequently introduced drug products would have a material adverse impact on our operating results.

Established pharmaceutical companies may invest heavily to accelerate discovery and development of novel compounds or to in-license novel compounds that could make our product candidates obsolete. Accordingly, our competitors may succeed in obtaining patent protection, receiving FDA approval or discovering, developing and commercializing medicines before we do. We are also aware of other companies that may currently be engaged in the discovery of medicines that will compete with the product candidates that we are developing.

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Reimbursement may not be available for oritavancin or our other product candidates, which could make it difficult for us to sell our products profitably.

Market acceptance and sales of oritavancin or our product candidates will depend on reimbursement policies and may be affected by future health care reform measures. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which drugs they will pay for and establish reimbursement levels. We cannot be sure that reimbursement will be available for oritavancin or any of our other product candidates. Also, we cannot be sure that reimbursement amounts will not reduce the demand for, or the price of, our products. If reimbursement is not available or is available only to limited levels, we may not be able successfully to commercialize oritavancin or any of our other products.

In both the United States and certain foreign jurisdictions, there have been a number of legislative and regulatory changes to the health care system that could impact our ability to sell our products profitably. In particular, the Medicare Modernization Act of 2003 added an outpatient prescription drug benefit to Medicare, which became effective on January 1, 2006. Drug benefits under this provision are administered through private plans that negotiate price concessions from pharmaceutical manufacturers. We cannot be certain that oritavancin will successfully be placed on the list of drugs covered by particular health plans, plan formularies, nor can we predict the negotiated price for oritavancin, which will be determined by market factors. With respect to Medicaid, the Deficit Reduction Act of 2005 made several changes to the way pharmacies are reimbursed under Medicaid, most of which went into effect on January 1, 2007, which changes could lead to reduced drug prices. Many states have also created preferred drug lists and include drugs on those lists only when the manufacturers agree to pay a supplemental rebate. If oritavancin is not included on these preferred drug lists, physicians may not be inclined to prescribe it to their Medicaid patients.

As a result of legislative proposals and the trend towards managed health care in the United States, third-party payors are increasingly attempting to contain health care costs by limiting both coverage and the level of reimbursement of new drugs. They may also refuse to provide any coverage of uses of approved products for medical indications other than those for which the FDA has granted market approvals. As a result, significant uncertainty exists as to whether and how much third-party payors will reimburse patients for their use of newly-approved drugs, which in turn will put pressure on the pricing of drugs. The availability of numerous generic antibiotics at lower prices than branded antibiotics, such as oritavancin, if it were approved for commercial introduction, may also substantially reduce the likelihood of reimbursement for oritavancin. We expect to experience pricing pressures in connection with the sale of our products due to the trend toward managed health care, the increasing influence of health maintenance organizations and additional legislative proposals.

Our ability to pursue the development and commercialization of oritavancin depends upon the continuation of our license from Lilly.

Our license agreement with Lilly provides us with a worldwide exclusive license to develop and sell oritavancin in fields relating to infectious diseases. Pursuant to the license agreement, we are required to make certain milestone and royalty payments to Lilly. The license rights to oritavancin granted to us could revert to Lilly if we do not continue to use commercially reasonable efforts to develop and commercialize an oritavancin drug product or if we otherwise materially breach the agreement. In addition, either we or Lilly may terminate the license agreement upon the other party’s insolvency or uncured material breach of the agreement. If our license agreement with Lilly were terminated, we would lose our rights to develop and commercialize oritavancin, which would materially and adversely affect our business, results of operations and future prospects.

Even if our product candidates receive regulatory approval, commercialization of these products may be adversely affected by regulatory actions.

Even if we receive regulatory approval, this approval may include limitations on the indicated uses for which we can market our medicines. Further, if we obtain regulatory approval, a marketed medicine and its

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manufacturer are subject to continual review, including review and approval of the manufacturing facilities. Discovery of previously unknown problems with a medicine may result in restrictions on its permissible uses, or on the manufacturer, including withdrawal of the medicine from the market. The FDA and similar foreign regulatory bodies may also implement new standards or change their interpretation and enforcement of existing standards and requirements for the manufacture, packaging or testing of products at any time. If we are unable to comply, we may be subject to regulatory or civil actions or penalties that could significantly and adversely affect our business. Any failure to maintain regulatory approval will limit our ability to commercialize our product candidates, which would materially and adversely affect our business, operating results and financial condition.

We rely on third parties to conduct our clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval for or commercialize our product candidates.

We have agreements with third-party contract research organizations to provide monitors for and to manage data for our ongoing clinical programs. We rely heavily on these parties for execution of our pre-clinical and clinical studies, and control only certain aspects of their activities. Nevertheless, we are responsible for ensuring that each of our studies is conducted in accordance with the applicable protocol. We and our contract research organizations are required to comply with current good clinical practices, which are regulations and guidelines enforced by the FDA for all of our products in clinical development. The FDA enforces these good clinical practices regulations through periodic inspections of trial sponsors, principal investigators and trial sites. If we or our contract research organizations fail to comply with applicable good clinical practices regulations, the clinical data generated in our clinical trials may be deemed unreliable and the FDA may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that, upon inspection, the FDA will determine that any of our clinical trials comply with good clinical practices regulations. In addition, our clinical trials must be conducted with product produced under good manufacturing practices regulations, and will require a large number of test subjects. Our failure to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process.

Our contract research organizations have the right to terminate their agreements with us in the event of an uncured material breach. In addition, some of our contract research organizations have an ability to terminate their respective agreements with us if it can be reasonably demonstrated that the safety of the subjects participating in our clinical trials warrants such termination, if we make a general assignment for the benefit of our creditors or if we are liquidated.

If any of our relationships with these third-party contract research organizations terminate, we may not be able to enter into arrangements with alternative contract research organizations. If contract research organizations do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols, regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. As a result, our financial results and the commercial prospects for our product candidates would be harmed, our costs could increase and our ability to generate revenue could be delayed.

We have recently hired additional contract research organizations to obtain additional resources and expertise to accelerate our progress with regard to on-going clinical programs and the synthesis of clinical trial data for submission with our NDA for oritavancin. Switching or adding additional contract research organizations involves substantial cost and requires extensive management time and focus. In addition, there is a natural transition period when a new contract research organization commences work. As a result, delays occur, which can materially impact our ability to meet our desired clinical development timelines. Though we carefully manage our relationships with our contract research organizations, there can be no assurance that we will not encounter similar challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our operating results, financial condition or future prospects.

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We will be completely dependent on third parties to manufacture oritavancin, and our commercialization of oritavancin could be stopped, delayed or made less profitable if those third parties fail to provide us with sufficient quantities of oritavancin or fail to do so at acceptable quality levels or prices.

We do not have the capability to manufacture our own oritavancin active pharmaceutical ingredient (or API). As a result, we have entered into a manufacturing and supply agreement with Abbott to manufacture and supply us with bulk oritavancin API for clinical and commercial purposes. Abbott is our sole provider of our supply of oritavancin API. Pursuant to our agreement with Abbott, Abbott currently stores some oritavancin API at its facilities in Illinois and the FDA has agreed to consider the use by us of oritavancin API produced by Abbott, upon regulatory approval, for commercial launch. It is possible, however, that if and when we receive regulatory approval to market and sell oritavancin, our current supply of oritavancin API may have exceeded its useful life and no longer be appropriate for commercial sale.

In addition, we do not have the capability to package oritavancin finished drug product for distribution to hospitals and other customers. Consequently, we have entered into an agreement with Catalent to supply us with finished product, to be packaged 100 milligrams in 20 cc vials. Prior to commercial launch, we intend to enter into a similar agreement with an alternate fill/finish drug product supplier for oritavancin so that we can ensure proper supply chain management once we are authorized to make commercial sales of oritavancin. Once finalized, we expect that the selected alternate supplier will provide us with finished drug product, also packaged 100 milligrams in a 20 cc vial. If we receive marketing approval from the FDA, we intend to sell drug product finished and packaged by either Catalent or this alternate supplier.

We have entered into long-term agreements with each of Abbott and Catalent. In the case of the agreement with Abbott, either party to this agreement may terminate the agreement with at least two years advance notice if the terminating party determines in good faith that the clinical development and/or commercialization of oritavancin of the bulk drug substance, before or after the first commercial sale made by us, is not technically or commercially feasible or if it is not economically justifiable. After the initial term of this agreement, which extends until December 31, 2014, the agreement automatically renews for successive two year terms unless terminated by either party with at least twelve months’ notice. If we change the specifications for the bulk drug substance Abbott is to produce, or the FDA or another regulatory body requires us to change the manufacturing specification for the bulk drug substance, and that change would increase Abbott’s manufacturing costs, we must reach an agreement with Abbott about how to allocate the costs associated with the change. If we cannot reach agreement, Abbott may refuse to implement the change, or may terminate the agreement. Further, Abbott may terminate this agreement if the FDA has not approved an NDA prior to January 1, 2010. Finally, either we or Abbott may terminate this agreement on 60 days’ written notice in the event of insolvency of or uncured material breach by the other party.

Our agreement with Catalent provides for an initial three year term continuing until March 27, 2010. Either party may terminate this agreement on 60 days’ written notice in the event of an uncured material breach. In addition, Catalent may suspend production under this agreement until any outstanding payments are brought current. Finally, either party may terminate this agreement upon the other party’s insolvency. We have not yet entered into a long-term agreement with any alternate fill/finish suppliers, but we intend to do so prior to commercial launch of oritavancin in order to ensure that we maintain adequate supplies of finished drug product.

If, for any reason, these third parties are unable or unwilling to perform, we may not be able to terminate our agreements with them, and we may not be able to locate alternative manufacturers or formulators or enter into favorable agreements with them. If Catalent or any alternate supplier of finished drug product, or in particular, Abbott, experiences any significant difficulties in its respective manufacturing processes for oritavancin API or finished product, we could experience significant interruptions in the supply of oritavancin. We note that in connection with the production of a series of three validation lots, one of the manufacturing lots recently failed to meet the required specifications such that it had to be reproduced. Were we to encounter manufacturing issues such as this on a larger scale in the future, our ability to produce a sufficient supply of oritavancin might be negatively affected. Our inability to coordinate the efforts of our third party manufacturing partners, or the lack

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of capacity available at our third party manufacturing partners, could impair our ability to supply oritavancin at required levels. Because of the significant regulatory requirements that we would need to satisfy in order to qualify a new bulk or finished product supplier, if we face these or other difficulties with our current suppliers, we could experience significant interruptions in the supply of oritavancin if we decided to transfer the manufacture of oritavancin to one or more alternative suppliers in an effort to deal with the difficulties.

We cannot guarantee that Abbott, Catalent or alternative manufacturers will be able to reduce the costs of commercial scale manufacturing of oritavancin over time. If the manufacturing costs of oritavancin remain at current levels, these costs may significantly impact our operating results. In order to reduce costs, we may need to develop and implement process improvements. However, in order to do so, we will need, from time to time, to notify or make submissions with regulatory authorities, and the improvements may be subject to approval by such regulatory authorities. We cannot be sure that we will receive these necessary approvals or that these approvals will be granted in a timely fashion. We also cannot guarantee that we will be able to enhance and optimize output in our commercial manufacturing process. If we cannot enhance and optimize output, we may not be able to reduce our costs over time.

We believe we have sufficient quantities of manufactured drug substance and have contracted with Catalent to formulate drug product to complete all of the currently planned clinical studies of oritavancin. Further, we plan to have Abbott, Catalent and any alternate suppliers later identified manufacture and package additional bulk drug substance and finished drug product in connection with commercial launch in the event oritavancin is approved for sale by regulatory authorities. If we are unable to do so in a timely manner, the commercial introduction of oritavancin, if approved by the FDA, would be adversely affected.

If the FDA does not approve the manufacturing facilities of Abbott, Catalent or any later identified manufacturing partners, we may be unable to develop or commercialize oritavancin.

We rely on Abbott and Catalent to manufacture bulk oritavancin API and finished drug product, respectively, and currently have no plans to develop our own manufacturing facility. In addition, we expect to add an alternate fill/finish provider prior to commercial launch of oritavancin. The facilities used by our contract manufacturers to manufacture our product candidates must be approved by the FDA, which inspections will be completed after we submit our NDA to the FDA. We do not control the manufacturing process of oritavancin and are completely dependent on our contract manufacturing partners—currently, Abbott and Catalent—for compliance with the FDA’s requirements for manufacture of finished oritavancin drug product. If our contract manufacturers cannot successfully manufacture material that conforms to our specifications and the FDA’s strict regulatory requirements, they will not be able to secure FDA approval for the manufacturing facilities. If the FDA does not approve these facilities for the manufacture of oritavancin, we may need to find alternative manufacturing facilities, which would result in significant delays of up to several years in obtaining approval for and manufacturing oritavancin.

In addition, our contract manufacturers will be subject to ongoing periodic unannounced inspections by the FDA and corresponding state and foreign agencies for compliance with current Good Manufacturing Practices, or cGMPs, and similar regulatory requirements. These cGMP regulations cover all aspects of the manufacturing, testing, quality control and record keeping relating to our product candidates. We do not have control over our contract manufacturers’ compliance with these regulations and standards. Failure by any of our contract manufacturers to comply with applicable regulations could result in sanctions being imposed on us, including fines, injunctions, civil penalties, failure to grant approval to market our product candidates, delays, suspensions or withdrawals of approvals, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect our business. In addition, we have no control over the ability of our contract manufacturers to maintain adequate quality control, quality assurance and qualified personnel. Failure by our contract manufacturers to comply with or maintain any of these standards could adversely affect our ability to develop, obtain regulatory approval for or market our product candidates.

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In order to satisfy regulatory authorities, we may need to reformulate the way in which our oritavancin API is created to remove animal source product.

Presently, our oritavancin API is manufactured using animal source product—namely porcine source product. Certain non-US regulatory authorities have historically objected to the use of animal source product—particularly bovine source product—in manufactured drug product. As a result and in order to best position oritavancin for approval in foreign jurisdictions, we have entered into an agreement with Abbott whereby we, along with Abbott, are seeking to develop a manufacturing process for oritavancin API that does not rely on the use of any animal source product.

Although we believe that we can develop a manufacturing process for oritavancin API that does not rely on the use of animal source product, there can be no assurance that we, along with Abbott, will be successful in this endeavor. If we are unable to remove animal source product from the manufacturing process for oritavancin API, it is possible that we will be unable to receive regulatory authority for oritavancin in certain foreign jurisdictions, which would likely have a negative impact on our ability to achieve our business objectives.

We may encounter delays in filling customer orders or incur substantial losses if our supply of bulk and finished drug product, which are produced and packaged for us by third party manufacturers, is interrupted.

Once Abbott has completed production of oritavancin bulk drug product at its facilities in Illinois, the product is shipped to Catalent’s facilities in Arizona for processing, packaging and labeling as final drug product. These shipments are of significant value and, while in transit, could be lost or damaged. Moreover, at any time after being shipped, our oritavancin API or finished drug product could be lost or damaged as it is stored with Catalent, our current finished product manufacturer, or, additionally, in the future, when it is stored at the facilities of any alternate fill/finish supplier. Depending on when in this process the API or finished drug product is lost or damaged, we may have limited recourse for recovery manufacturers or insurers. As a result, our financial performance could be impacted by any such loss of or damage to our oritavancin API.

We also may experience interruption or significant delay in the supply of oritavancin API or finished drug product due to natural disasters, acts of war or terrorism, shipping embargoes, labor unrest or political instability. In any such event, the supply of oritavancin API stored at Abbott and the oritavancin finished drug product stored with Catalent or any alternate fill/finish supplier could also be impacted. We may also be subject to financial risk from volatile fuel costs associated with shipping oritavancin API or finished drug product within the United States and, once we have received necessary foreign approvals, to our international distribution partners for packaging, labeling and distribution.

If we fail to obtain the capital necessary to fund our operations, we may be unable to develop our product candidates and we could be forced to share our rights to commercialize our product candidates with third parties on terms that may not be favorable to us.

We need large amounts of capital to support our research and development efforts. If we are unable to secure capital to fund our operations, we will not be able to continue our discovery and development efforts and we might have to enter into strategic collaborations that could require us to share commercial rights to our products and product candidates with third parties in ways that we currently do not intend. Based on our current operating plans, and after giving effect to the receipt of the net proceeds of this offering, we believe that our cash and cash equivalents and marketable securities will be sufficient to meet our anticipated operating needs into 2009. Depending on the status of regulatory approval or, if approved, commercialization of oritavancin, as well as the progress we make in selling that product candidate, we may require additional capital to fund operating needs thereafter.

Further, we are party to a license agreement with Lilly pursuant to which we are obligated to make certain cash milestone payments to Lilly upon the receipt of certain regulatory approvals of our oritavancin product. In

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addition, we are required to make certain cash royalty payments upon our achievement of target levels of commercial sales of our oritavancin product. We are also obligated to make a future cash milestone payment to InterMune upon our receipt from the FDA of all approvals necessary for the commercial launch of oritavancin. Though we believe that these royalty rates and milestone payments are reasonable in light of our business plan, we will require large amounts of capital to satisfy these obligations.

We may also need to raise additional funds sooner if we choose to expand more rapidly than we presently anticipate. To raise additional funds, we may seek to sell additional equity or debt securities, or both, or incur other indebtedness. The sale of additional equity or debt securities, if convertible, could result in the issuance of additional shares of our capital stock and could result in dilution to our stockholders. The incurrence of indebtedness would result in increased fixed payment obligations and could also result in certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. We cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we will be prevented from pursuing research and development efforts. This could harm our business, operating results and financial condition and cause the price of our common stock to fall.

We currently have no sales organization. If we are unable to establish satisfactory sales and marketing capabilities, we may not succeed in commercializing oritavancin.

At present, we have no sales personnel and a limited number of marketing personnel. In anticipation of receiving FDA approval for the commercial launch of oritavancin, we anticipate beginning to hire additional sales and marketing personnel to establish our own sales and marketing capabilities in the United States in time for our anticipated commercial launch of oritavancin. We plan to add our first sales representatives in the first quarter of 2008. Therefore, at the time of our anticipated commercial launch of oritavancin, assuming regulatory approval of the drug by the FDA, our sales and marketing team will have worked together for only a limited period of time. We cannot guarantee that we will be successful in marketing oritavancin in the United States.

We may not be able to establish a direct sales force in a cost effective manner or realize a positive return on this investment. In addition, we will have to compete with other pharmaceutical and biotechnology companies to recruit, hire, train and retain sales and marketing personnel. Factors that may inhibit our efforts to commercialize our products without strategic partners or licensees include:

If appropriate regulatory approvals are obtained, we intend to commercialize oritavancin and our other product candidates in international markets through collaboration arrangements with third parties. We have not yet entered into any agreements related to the marketing of oritavancin or any of our other product candidates in international markets and we may not be able to enter into any arrangements with respect to international collaborations on favorable terms or at all. In addition, these arrangements could result in lower levels of income to us than if we marketed our product candidates entirely on our own. If we are unable to enter into appropriate marketing arrangements for our product candidates in international markets, we may not be able to develop an effective international sales force to successfully commercialize oritavancin and our other product candidates in

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international markets. If we fail to enter into marketing arrangements for our products and are unable to develop an effective international sales force, our ability to generate revenue would be limited as a significant portion of the market opportunity for oritavancin and our other product candidates is likely to be in international markets.

If we are not successful in recruiting sales and marketing personnel or in building a sales and marketing infrastructure or if we do not successfully enter into appropriate collaboration arrangements with third parties, we will have difficulty commercializing oritavancin and our other product candidates, which would adversely affect our business, operating results and financial condition.

A variety of risks associated with our international business relationships could materially adversely affect our business.

If approved for commercialization, we expect oritavancin to be marketed worldwide. Consequently, we expect that we will be subject to additional risks related to operating in foreign countries including:

These and other risks associated with our international operations may materially adversely affect our ability to attain or maintain profitable operations.

In order to establish our sales and marketing infrastructure, we will need to grow the size of our organization, and we may experience difficulties in managing this growth.

As of June 15, 2007, we employed 77 employees. As our development and commercialization plans and strategies develop, we expect to need to expand the size of our employee base for managerial, operational, sales, marketing, financial and other resources. Future growth would impose significant added responsibilities on members of management, including the need to identify, recruit, maintain, motivate and integrate additional employees. Also, our management may have to divert a disproportionate amount of its attention away from our day-to-day activities and devote a substantial amount of time to managing these growth activities. Our future financial performance and our ability to commercialize oritavancin and our other product candidates and compete effectively will depend, in part, on our ability to effectively manage any future growth.

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If we are not successful in attracting and retaining highly qualified personnel, we may not be able to successfully implement our business strategy.

Our ability to compete in the highly competitive biotechnology and pharmaceuticals industries depends in large part upon our ability to attract and retain highly qualified managerial, scientific and medical personnel. We are highly dependent on our management, scientific and medical personnel. In order to induce valuable employees to remain at Targanta, we have provided options that vest over time. The value to employees of options that vest over time is significantly affected by movements in our stock price that we cannot control and may at any time be insufficient to counteract more lucrative offers from other companies.

Our scientific team has expertise in many different aspects of drug discovery and development. We conduct our operations at our facilities in Cambridge, Massachusetts, Indianapolis, Indiana and Montreal, Québec, Canada. These areas are headquarters to many other biopharmaceutical companies and many academic and research institutions and, as a result, there is currently a shortage of experienced scientists, which is likely to continue. Competition for skilled personnel in our market is very intense and competition for experienced scientists may limit our ability to hire and retain highly qualified personnel on acceptable terms.

Despite our efforts to retain valuable employees, members of our management, scientific and medical teams may terminate their employment with us on short notice. While we have employment agreements with certain of our employees, these employment arrangements provide for at-will employment, which means that any of our employees could leave our employment at any time, with or without notice. The loss of the services of any of our executive officers or other key employees could potentially harm our business, operating results or financial condition. Our success also depends on our ability to continue to attract, retain and motivate highly skilled junior, mid-level, and senior managers as well as junior, mid-level, and senior scientific and medical personnel.

Other biotechnology and pharmaceutical companies with which we compete for qualified personnel have greater financial and other resources, different risk profiles, and a longer history in the industry than we do. They also may provide more diverse opportunities and better chances for career advancement. Some of these characteristics may be more appealing to high quality candidates than what we have to offer. If we are unable to continue to attract and retain high quality personnel, the rate and success at which we can discover, develop and commercialize drug candidates would be limited.

We may acquire additional businesses or form strategic alliances in the future, and we may not realize the benefits of such acquisitions.

We may acquire additional businesses or products, form strategic alliances or create joint ventures with third parties that we believe will complement or augment our existing business. If we acquire businesses with promising markets or technologies, we may not be able to realize the benefit of acquiring such businesses if we are unable to successfully integrate them with our existing operations and company culture. We may have difficulty in developing, manufacturing and marketing the products of a newly acquired company that enhances the performance of our combined businesses or product lines to realize value from expected synergies. We cannot assure that, following an acquisition, we will achieve the revenues or specific net income that justifies the acquisition.

Risks Related to Legal Uncertainty

If our efforts to protect the proprietary nature of the intellectual property related to our technologies are not adequate, we may not be able to compete effectively in our market.

We rely upon a combination of patents, trade secret protection and confidentiality agreements to protect the intellectual property related to our technologies. Any involuntary disclosure to or misappropriation by third

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parties of our confidential proprietary information could enable competitors to quickly duplicate or surpass our technological achievements, thus eroding our competitive position in our market. The strength of patents in the biotechnology and pharmaceutical field involves complex legal and scientific questions and can be uncertain.

As of March 31, 2007, through our license agreement with Lilly, we licensed from Lilly 35 issued United States patents, three pending United States patent applications, approximately 460 granted foreign patents and approximately 95 foreign national patent applications. We also have three pending United States patent applications filed in relation to aspects of oritavancin discovered by our scientists. After the patent related to the composition of oritavancin expires on November 24, 2015, we will not be able to use this patent to block others from marketing oritavancin in the United States. We believe, however, that under Hatch-Waxman legislation, the composition of matter patent covering oritavancin may be eligible to be extended for up to an additional five years.

Third parties may challenge the patents we license. Further, the patent applications that we license may fail to result in issued patents. Further, the existing or future patents to which we have rights based on our agreement with Lilly may be too narrow to prevent third parties from developing or designing around these patents. Manufacturers of generic drugs may also seek to obtain approval to sell a generic version of oritavancin prior to the expiration of the patent on the composition of oritavancin. If the sufficiency of the breadth or strength of protection provided by the patents we license with respect to oritavancin or the patents we pursue related to another product candidate is threatened, it could dissuade companies from collaborating with us to develop, and threaten our ability to commercialize oritavancin and our other product candidates. Further, if we encounter delays in our clinical trials, the period of time during which we could market our drug candidates under patent protection would be reduced.

In addition to the protection afforded by patents, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that is not patentable, for processes for which patents are difficult to enforce and for any other elements of our drug discovery and development processes that involve proprietary know-how, information and technology that is not covered by patents. Although we require all of our employees, consultants, advisors and any third parties who have access to our proprietary know-how, information and technology to enter into confidentiality agreements, we cannot be certain that this know-how, information and technology will not be disclosed or that competitors will not otherwise gain access to our trade secrets or independently develop substantially equivalent information and techniques. Further, the laws of some foreign countries do not protect proprietary rights to the same extent as the laws of the United States and Canada. As a result, we may encounter significant problems in protecting and defending our intellectual property both in the United States and abroad. If we are unable to prevent material disclosure of the intellectual property related to our technologies to third parties, we will not be able to establish or, if established, maintain a competitive advantage in our market, which could materially adversely affect our business, operating results and financial condition.

Third-party claims of intellectual property infringement may prevent or delay our drug discovery and development efforts.

Our commercial success depends in part on our avoiding infringement of the patents and proprietary rights of third parties. Third parties may assert that we are employing their proprietary technology without authorization. There may be third party patents with claims to materials, methods of manufacture or methods for treatment related to the use or manufacture of oritavancin and/or our other product candidates. Our commercial success depends in part on our avoiding infringement of the patents and proprietary rights of third parties. Third parties may assert that we are employing their proprietary technology without authorization. There may be third party patents with claims to materials, methods of manufacture or methods for treatment related to the use or manufacture of oritavancin and/or our other product candidates. At present, we are not aware of any patent claims with merit that would adversely and materially affect our ability to develop our product candidates. We are, however, aware of two United States patents, and European, Canadian and Japanese counterpart patents, with claims to naturally occurring molecules that may be produced in trace amounts as contaminants during the manufacture of oritavancin. Derivatives of these molecules may also be present in the final oritavancin product. Based on our review of the United States patents and their issued claims, we do not believe that their existence

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would block our ability to manufacture or commercialize oritavancin in the United States, assuming we receive regulatory approval to market oritavancin in the United States. Furthermore, both of these third-party United States patents will expire by the end of December 2008. Thus, it is likely that at least one, if not both, of the United States patents will be expired by the time we obtain approval to market oritavancin in the United States. We cannot rule out the possibility of third party allegations related to these or any other patents. If these or any other patents were held by a court of competent jurisdiction to cover the oritavancin manufacturing process, any molecules formed during the manufacturing process or the final oritavancin product itself, the holders of any such patents may be able to block our ability to commercialize oritavancin unless we obtained a license under the applicable patent or patents, or until such patents expire. We cannot predict whether we would be able to obtain a license on commercially reasonable terms, if at all. Any inability to obtain such a license under the applicable patents on commercially reasonable terms, or at all, may have a material adverse effect on our ability to commercialize oritavancin until such patents expire.

In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents. Furthermore, parties making claims against us may obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize one or more of our product candidates. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business. In the event of a successful claim of infringement against us, we may have to pay substantial damages, obtain one or more licenses from third parties or pay royalties. In addition, even in the absence of litigation, we may need to obtain licenses from third parties to advance our research or allow commercialization of our product candidates, and we have done so from time to time. We may fail to obtain future licenses at a reasonable cost or on reasonable terms, if at all. In that event, we may be unable to further develop and commercialize one or more of our product candidates, which could harm our business significantly.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive and time consuming.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming. In addition, in an infringement proceeding, a court may decide that a patent of ours or our licensors is not valid or is unenforceable, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation or defense proceedings could put one or more of our patents at risk of being invalidated or interpreted narrowly and could put our patent applications at risk of not issuing.

Interference proceedings brought by the United States Patent and Trademark Office may be necessary to determine the priority of inventions with respect to our patent applications or those of our collaborators or licensors. Litigation or interference proceedings may fail and, even if successful, may result in substantial costs and distraction of our management. We may not be able to prevent, alone or with our licensors, misappropriation of our proprietary rights, particularly in countries where the laws may not protect those rights as fully as in the United States.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock.

Product liability lawsuits could divert our resources, result in substantial liabilities and reduce the commercial potential of our medicines.

The risk that we may be sued on product liability claims is inherent in the development of pharmaceutical products. These lawsuits may divert our management from pursuing our business strategy and may be costly to

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defend. In addition, if we are held liable in any of these lawsuits, we may incur substantial liabilities and may be forced to limit or forgo further commercialization of those products.

Although we maintain general liability and product liability insurance, this insurance may not fully cover potential liabilities. In addition, inability to obtain or maintain sufficient insurance coverage at an acceptable cost or to otherwise protect against potential product liability claims could prevent or inhibit the commercial production and sale of our products, which could adversely affect our business, operating results and financial condition.

If we use hazardous and biological materials in a manner that causes injury or violates applicable law, we may be liable for damages.

Our research and development activities involve the controlled use of potentially hazardous substances, including chemical, biological and radioactive materials and viruses. In addition, our operations produce hazardous waste products. Federal, state and local laws and regulations in both the United States and Canada govern the use, manufacture, storage, handling and disposal of hazardous materials. Although we believe that our procedures for use, handling, storing and disposing of these materials comply with legally prescribed standards, we may incur significant additional costs to comply with applicable laws in the future. Also, even if we are in compliance with applicable laws, we cannot completely eliminate the risk of contamination or injury resulting from hazardous materials and we may incur liability as a result of any such contamination or injury. In the event of an accident, we could be held liable for damages or penalized with fines, and the liability could exceed our resources. We do not have any insurance for liabilities arising from hazardous materials. Compliance with applicable environmental laws and regulations is expensive, and current or future environmental regulations may impair our research, development and production efforts, which could harm our business, operating results and financial condition.

General Company-Related Risks

Our stock price may be volatile, and the value of our stock could decline.

The trading price of our common stock is likely to be volatile. Our stock price could be subject to wide fluctuations in response to a variety of factors, including the following:

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In addition, the stock market in general, and The Nasdaq Global Market and biotechnology companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance. In the past, following periods of volatility in the market price of a company’s securities, securities class action litigation has often been instituted against companies. This type of litigation, if instituted, could result in substantial costs and a diversion of management’s attention and resources, which would harm our business, operating results or financial condition.

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

The 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 $               per share, based on an initial public offering price of $               per share. Further, investors purchasing common stock in this offering will contribute approximately           % of the total amount invested by stockholders since our inception, but will own only approximately           % 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. In addition, as of June 15, 2007, options to purchase 1,800,616 shares of our common stock at a weighted average exercise price of $5.06 per share and warrants exercisable for up to 598,751 shares of our common stock at a weighted average price of $13.87 per share were outstanding. The exercise of any of these options or warrants would result in additional dilution. As a result of the dilution to investors purchasing shares in this offering, investors may receive significantly less than the purchase price paid in this offering, if anything, in the event of a liquidation of our Company.

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We will incur significant increased costs as a result of operating as a public company, and our management will be required to devote substantial time to new compliance initiatives.

As a public company, we will incur significant legal, accounting and other expenses that we did not incur as a private company. In addition, the Sarbanes-Oxley Act, as well as rules subsequently implemented by the Securities and Exchange Commission and The Nasdaq Global Market, have imposed various new requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and changes in corporate governance practices. Our management and other personnel will need to devote a substantial amount of time to these new compliance initiatives. Moreover, these rules and regulations will increase our legal and financial compliance costs and will make some activities more time-consuming and costly. For example, we expect these rules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance and we may be required to incur substantial costs to maintain the same or similar coverage.

The Sarbanes-Oxley Act requires, among other things, that we maintain effective internal controls for financial reporting and disclosure controls and procedures. In particular, we will be required to perform system and process evaluation and testing of our internal controls over financial reporting to allow management and our independent registered public accounting firm to report, commencing in our annual report on Form 10-K for the year ending December 31, 2008, on the effectiveness of our internal controls over financial reporting, as required by Section 404 of the Sarbanes-Oxley Act. Our testing, or the subsequent testing by our independent registered public accounting firm, may reveal deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses. Our compliance with Section 404 will require that we incur substantial accounting expense and expend significant management efforts. We currently do not have an internal audit group, and we will need to hire additional accounting and financial staff with appropriate public company experience and technical accounting knowledge. Moreover, if we are not able to comply with the requirements of Section 404 in a timely manner or if we or our independent registered public accounting firm identifies deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses, the market price of our stock could decline and we could be subject to sanctions or investigations by Nasdaq, the Securities and Exchange Commission or other regulatory authorities, which would require additional financial and management resources.

Sales of a substantial number of shares of our common stock in the public market could cause our stock price to fall.

Sales of a substantial number of shares of our common stock in the public market or the perception that these sales might occur, could depress the market price of our common stock and could impair our ability to raise capital through the sale of additional equity securities. We are unable to predict the effect that sales may have on the prevailing market price of our common stock.

Substantially all of our existing stockholders are subject to lock-up agreements with the underwriters of this offering that restrict the stockholders’ ability to transfer shares of our common stock for at least 180 days from the date of this prospectus. The lock-up agreements limit the number of shares of common stock that may be sold immediately following the public offering. Subject to certain limitations, approximately 11,374,891 of our total outstanding shares will be eligible for sale upon expiration of the lock-up period. In addition, shares issuable upon exercise of options and warrants vested as of the expiration of the lock-up period will be eligible for sale at that time. Sales of stock by these stockholders could have a material adverse effect on the trading price of our common stock.

Certain holders of shares of our common stock are entitled to rights with respect to the registration of their shares under the Securities Act of 1933, as amended (or the Securities Act), subject to the 180-day lock-up arrangement described above. Registration of these shares under the Securities Act would result in the shares becoming freely tradable without restriction under the Securities Act, except for shares purchased by affiliates. Any sales of securities by these stockholders could have a material adverse effect on the trading price of our common stock.

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Future sales and issuances of our common stock or rights to purchase common stock, including pursuant to our equity incentive plans, could result in additional dilution of the percentage ownership of our stockholders and could cause our stock price to fall.

We expect that significant additional capital will be needed in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. We may sell common stock, convertible securities or other equity securities in one or more transactions at prices and in a manner we determine from time to time. If we sell common stock, convertible securities or other equity securities in more than one transaction, investors may be materially diluted by subsequent sales. Such sales may also result in material dilution to our existing stockholders, and new investors could gain rights superior to existing stockholders.

Pursuant to our 2007 Equity Incentive Plan, our management is authorized to grant stock options to our employees, directors and consultants. The number of shares available for future grant under our 2007 Equity Incentive Plan will automatically increase each year by an amount equal to 3.5% of all shares of our capital stock outstanding as of January 1 ^st of each year, subject to the ability of our board of directors to take action to reduce the size of such increase in any given year.

All of the shares of common stock sold in our initial public offering will be freely tradable without restrictions or further registration under the Securities Act, as amended, except for any shares purchased by our affiliates as defined in Rule 144 under the Securities Act. Rule 144 defines an affiliate as a person that directly, or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, us and would include persons such as our directors and executive officers.

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

Our management will have broad discretion in the application of the net proceeds, including for any of the purposes described in the section entitled “Use of Proceeds.” The failure by our management to apply these funds effectively could harm our business. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders.

Our ability to utilize our net operating loss carryforwards and certain other tax attributes may be limited.

Under Section 382 of the Internal Revenue Code, if a corporation undergoes an “ownership change” (generally defined as a greater than 50% change (by value) in its equity ownership over a three year period), the corporation’s ability to use its pre-change net operating loss carryforwards and other pre-change tax attributes to offset its post-change income may be limited. We believe that, with our initial public offering, our most recent private placement and other transactions that have occurred over the past three years, we have triggered an “ownership change” limitation. We may also experience ownership changes in the future as a result of subsequent shifts in our stock ownership.

Some provisions of our charter documents and Delaware law may have anti-takeover effects that could discourage an acquisition of us by others, even if an acquisition would be beneficial to our stockholders.

Provisions in our certificate of incorporation and bylaws, as well as provisions of Delaware law, could make it more difficult for a third party to acquire us or increase the cost of acquiring us, even if doing so would benefit our stockholders. These provisions include:

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In addition, we are subject to Section 203 of the Delaware General Corporation Law, which generally prohibits a Delaware corporation from engaging in any of a broad range of business combinations with an interested stockholder for a period of three years following the date on which the stockholder became an interested stockholder, unless such transactions are approved by our board of directors. This provision could have the effect of delaying or preventing a change of control, whether or not it is desired by or beneficial to our stockholders. Further, other provisions of Delaware law may also discourage, delay or prevent someone from acquiring us or merging with us.

Our officers and directors and other affiliates may be able to exert significant control over the company.

After this offering, our executive officers, directors, 5% stockholders and their affiliates will control approximately           % of our outstanding common stock. Therefore, these stockholders will have the ability to influence the company through this ownership position.

These stockholders may be able to determine all matters requiring stockholder approval. For example, these stockholders may be able to control elections of directors, amendments of our organizational documents, or approval of any merger, sale of assets, or other major corporation transaction. This may prevent or discourage unsolicited acquisition proposals or offers for our common stock that you may feel are in your best interest as one of our stockholders.

Our corporate compliance program cannot ensure that we are in compliance with all applicable “fraud and abuse” laws and regulations and other applicable laws and regulations in the jurisdictions in which we sell oritavancin or other product candidates, and a failure to comply with these regulations or prevail in litigation related to noncompliance could harm our business.

Our general operations, and the research, development, manufacture, sale and marketing of our products, are subject to extensive laws and regulation, including but not limited to, health care “fraud and abuse” laws, such as the federal false claims act, the federal anti-kickback statute, and other state and federal laws and regulations. While we have developed and implemented a corporate compliance program based upon what we believe are current best practices, we cannot guarantee that this program will protect us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws or regulations. If any such actions are instituted against us and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines or other sanctions.

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