RISK FACTORS

Investing in our common stock involves a high degree of risk. These risks include, but are not limited to, those described below, each of which may be relevant to decisions regarding an investment in or ownership of our stock. You should consider carefully the risks described below, together with the other information contained in this prospectus or incorporated by reference in this prospectus. The realization of any of these risks could have a significant adverse effect on our reputation, business, financial condition, results of operations, growth, and ability to accomplish our strategic objectives. In that event, the price of our common stock could decline, and you could lose part or all of your investment.

Risks Relating to our Financial Condition and Need for Additional Capital

We have a limited operating history and expect to generate significant losses for the foreseeable future. If we do not generate significant revenue, we will not be profitable.

With the exception of one year, we have incurred annual net operating losses since inception, and to date have generated only limited revenue from government contracts, service agreements, collaboration agreements, and reagent protein product sales. We have recorded net losses of $9.8 million, $4.1 million and $2.6 million for the years ending December 31, 2014, 2013 and 2012, respectively, and had an accumulated deficit of $113.3 million and net working capital of $45.0 million as of December 31, 2014. We have funded our operations primarily through the sale and issuance of common stock in our initial public offering, the sale and issuance of convertible preferred stock, our credit facility, and revenue from government contracts, service agreements, collaboration agreements and reagent protein product sales. As of December 31, 2014, we had capital resources consisting of cash and cash equivalents of $45.7 million. The sale and issuance of common stock in our initial public offering in July 2014, and the exercise of the underwriters’ option to purchase additional shares in August 2014, provided net proceeds of approximately $52.6 million before offering expenses of approximately $2.0 million.

As we continue to develop and invest more resources into the development and commercialization of our biosimilar product candidates, we expect that our expenses will increase substantially, and that our net operating losses will increase over the next several years. To become profitable, we must successfully develop and obtain regulatory approval for our product candidates, and effectively manufacture and commercialize the product candidates we develop. If we obtain regulatory approval to market a product candidate, our future revenue will depend upon the size of any markets in which our product candidates may receive approval, and our and our collaboration partners’ ability to achieve sufficient market acceptance, pricing, reimbursement from third-party payors, and adequate market share for our product candidates in those markets. We may never succeed in these activities and therefore may never generate revenue that is significant or large enough to achieve profitability. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable could depress the market price of our common stock and could impair our ability to raise capital, expand our business, diversify our product offerings or continue our operations.

Even if the offering is successful, we expect that we will require substantial additional funds to obtain regulatory approval for and commercialize our two most advanced biosimilar product candidates and any future product candidates and, if additional capital is not available, we may need to limit, scale back or cease our operations.

Since our inception, most of our resources have been dedicated to the preclinical and clinical development of our two most advanced biosimilar product candidates, PF582 and PF530. In the near term, we will incur substantial costs upon commencement of our Phase 3 trial for PF582 with Hospira. We believe that we will continue to expend substantial resources for the foreseeable future for the preclinical and clinical development of our current product pipeline, and the development of any other indications and product candidates we may

-12-

Table of Contents

choose to pursue, either alone or with our strategic collaboration partners. These expenditures will include costs associated with research and development, conducting preclinical studies and clinical trials, and manufacturing and supply as well as marketing and selling any products approved for sale. In addition, other unanticipated costs may arise. Because the outcome of any clinical trial is highly uncertain, we cannot reasonably estimate the actual amounts necessary to successfully complete the development and commercialization of PF582, PF530 and our pipeline of other product candidates and preclinical products under development.

We believe that our available cash and cash equivalents, including the proceeds from this offering, availability under our existing credit facilities, and any revenue from our government contracts, service agreements, collaboration agreements, and reagent protein product sales will allow us to fund our operations through at least the next 24 months. In addition, we may seek additional capital due to favorable market conditions or strategic considerations; even if we believe we have sufficient funds for our current or future operating plans. Our future capital requirements may vary depending on the following:

If we were to experience any delays or encounter issues with any of the above, including clinical holds, failed studies, inconclusive or complex results, safety or efficacy issues, or other regulatory challenges that require longer follow-up of existing studies, additional major studies, or additional supportive studies in order to pursue marketing approval, it could further increase the costs associated with the above and delay revenues.

If we seek additional funding in the future, additional funds may not be available to us on acceptable terms or at all. We may seek to raise additional funds through equity, equity-linked or debt financings. If we raise additional funds through the incurrence of indebtedness, such indebtedness would have rights that are senior to holders of our equity securities and could contain covenants that restrict our operations. Any additional equity financing may be dilutive to our stockholders. If we are unable to obtain funding on a timely basis, we may be required to significantly curtail the advancement of one or more of our product candidates. We also could be required to seek funds through arrangements with collaborators or others that may require us to relinquish rights to some of our technologies or product candidates which we would otherwise pursue on our own.

Our quarterly operating results may fluctuate significantly.

Our operating results are subject to quarterly fluctuations. Our net loss and other operating results are affected by numerous factors, including:

-13-

Table of Contents

If our quarterly operating results fall below the expectations of investors or securities analysts, the market price of our common stock could decline substantially. Furthermore, any quarterly fluctuations in our operating results may, in turn, cause the market price of our stock to fluctuate substantially.

Risks Relating to our Business and our Industry

If an improved version of a reference product, such as Lucentis or Betaseron, is developed, or if the market for a reference product significantly declines, sales or potential sales of our biosimilar product candidates may suffer.

Innovator companies may develop improved versions of a reference product as part of a life cycle extension strategy, and may obtain approval of the improved version under a supplemental biologics license application. If an innovator company succeeds in obtaining an approval of an improved product, it may capture a significant share of the collective reference product market and significantly reduce the market for the reference product, and thereby the potential size of the market for our biosimilar product candidates. In addition, the improved product may be protected by additional patent rights.

Additionally, competition in the pharmaceutical market is intense. Reference products face competition on numerous fronts as technological advances are made that may offer patients a more convenient form of administration or increased efficacy, or as new products are introduced. As new products are approved that compete with the reference product to our biosimilar product candidates, such as Lucentis or Betaseron, sales of the reference products may be significantly and adversely impacted and may render the reference product obsolete. If the market for the reference product is impacted, we in turn may lose significant market share or market potential for our products and product candidates. As a result, the value of our product pipeline could be negatively impacted and our business, prospects and financial condition could suffer.

Our product candidates, if approved, will face significant competition from the reference products and from other biosimilars of the reference products. Our failure to effectively compete may prevent us from achieving significant market penetration and expansion.

We expect to enter highly competitive pharmaceutical markets. Successful competitors in the pharmaceutical market have the ability to effectively discover, obtain patents, develop, test and obtain regulatory approvals for products, as well as the ability to effectively commercialize, market and promote approved products, including communicating the effectiveness, safety and value of products to consumers and medical professionals. Numerous companies, universities, and other research institutions are engaged in developing, patenting, manufacturing and marketing of products competitive with those that we are developing. Many of these potential competitors, such as Bayer AG, Novartis AG, Genentech, Inc. a wholly-owned member of the Roche Group, and Eli Lilly and Company are large, experienced companies that enjoy significant competitive advantages, such as substantially greater financial, research and development, manufacturing, personnel and marketing resources. Recent and potential future merger and acquisition activity in the biotechnology and pharmaceutical industries are likely to result in even more resources being concentrated among a smaller number of our competitors. These companies also maintain greater brand recognition and more experience and expertise in undertaking preclinical testing and clinical trials of product candidates, and obtaining FDA and other regulatory approvals of products. Established pharmaceutical companies may also invest heavily to accelerate discovery and development of novel compounds that could make our product candidates obsolete.

In addition, our biosimilar products may face competition from companies that develop and commercialize biosimilars that compete directly with our products. See “Risks Related to Government Regulation—If other

-14-

Table of Contents

biosimilars of Lucentis or Betaseron are approved and successfully commercialized before PF582 or PF530, our business would suffer . ”

Use of our product candidates could be associated with side effects or adverse events.

As with most pharmaceutical products, use of our product candidates could be associated with side effects or adverse events which can vary in severity (from minor reactions to death) and frequency (infrequent or prevalent). Side effects or adverse events associated with the use of our product candidates may be observed at any time, including in clinical trials or when a product is commercialized, and any such side effects or adverse events may negatively affect our and our collaboration partners’ ability to obtain regulatory approval or market our product candidates. Side effects such as toxicity or other safety issues associated with the use of our product candidates could require us or our collaboration partners to perform additional studies or halt development or sale of these product candidates or expose us to product liability lawsuits which will harm our business. We may be required by regulatory agencies to conduct additional animal or human studies regarding the safety and efficacy of our product candidates which we have not planned or anticipated. There can be no assurance that we will resolve any issues related to any product-related adverse events to the satisfaction of the FDA or any regulatory agency in a timely manner or ever, which could harm our business, prospects and financial condition.

In addition, if we and our collaboration partners are successful in commercializing PF582 and PF530 or any other product candidates the Food and Drug Administration, or FDA, European Medicines Agency, or EMA, European Economic Area Competent Authorities, or EEA Competent Authorities, and other foreign regulatory agency regulations require that we report certain information about adverse medical events if those products may have caused or contributed to those adverse events. The timing of our obligation to report would be triggered by the date we become aware of the adverse event as well as the nature of the event. We or our collaborators may fail to report adverse events we become aware of within the prescribed timeframe. We or our collaborators may also fail to appreciate that we or our collaborators have become aware of a reportable adverse event, especially if it is not reported to us as an adverse event or if it is an adverse event that is unexpected or removed in time from the use of our products. If we or our collaborators fail to comply with our reporting obligations, the FDA, the EMA, EEA Competent Authorities, or other foreign regulatory agencies could take action including criminal prosecution, the imposition of civil monetary penalties, seizure of our products, or delay in approval or clearance of future products.

If we fail to attract and keep senior management and key scientific personnel, we may be unable to successfully develop PF582, PF530 or any future product candidates, conduct our clinical trials and commercialize PF582, PF530 or any future product candidates we develop.

Our success depends in part on our continued ability to attract, retain and motivate highly qualified management, clinical and scientific personnel. We believe that our future success is highly dependent upon the contributions of our senior management, particularly our Chief Executive Officer, Chief Financial Officer and Chief Business Officer, as well as our senior scientists and other members of our senior management team. Employment agreements with each of our Chief Executive Officer, Chief Financial Officer, Chief Business Officer, and other senior executives, as well as our offer letters with our senior scientists, all provide for “at-will” employment. The loss of services of any of these individuals could delay or prevent the successful development of our product pipeline, completion of our planned clinical trials or the commercialization of PF582, PF530 or any future products we develop.

Although we have not historically experienced significant difficulties attracting and retaining qualified employees, we could experience such problems in the future. For example, competition for qualified personnel in the biotechnology and pharmaceuticals industry is intense due to the limited number of individuals who possess the skills and experience required. We will need to hire additional personnel as we expand our clinical development and commercial activities. We may not be able to attract and retain quality personnel on acceptable terms, or at all, which may cause our business and operating results to suffer.

-15-

Table of Contents

We currently rely on a limited number of collaboration partners for a substantial portion of our revenue. The loss of or a change in any significant collaboration partner, including its credit worthiness, could materially reduce our revenue and adversely impact our financial position.

Three collaboration partners accounted for more than 10% of our revenue in 2014 and 2012, and two collaboration partners accounted for more than 10% of our 2013 revenue. BARDA, NIAID and Boehringer Ingelheim International GmbH each accounted for more than 10% of our revenue in 2014. In 2013, BARDA and Leidos each accounted for more than 10% of our revenue. In 2012, BARDA, Leidos and MedImmune, LLC each accounted for more than 10% of our revenue. Additionally, there was one additional entity accounting for more than 10% of our revenue in 2013; however, this was the result of a one-time transaction and is not expected to provide significant revenue going forward.

We have also entered into an agreement with Hospira to develop and commercialize PF582. The prospects for this product candidate depend in part on the expertise, development and commercial skills, and financial strength of Hospira. The loss of any key collaboration partner or any significant adverse change in the size or terms of a contract with a key collaboration partner could significantly reduce our revenue over the short term. Moreover, having our revenue concentrated among a limited number of entities creates a concentration of financial risk for us, and in the event that any significant collaboration partner is unable to fulfill its payment obligations to us, our operating results and cash position would suffer . See “Risks Relating to our Reliance on Third Parties—We are substantially dependent on the expertise of Hospira and Strides Arcolab to develop and commercialize some of our product candidates. If we fail to maintain our current strategic relationship with Hospira and Strides Arcolab, our business, commercialization prospects and financial condition may be materially adversely affected.”

We currently have limited marketing capabilities and no sales organization.

We currently have limited sales and marketing capabilities. We have no prior experience in the marketing, sale and distribution of pharmaceutical products and there are significant risks involved in building and managing a sales organization, including our ability to hire, retain and incentivize qualified individuals, generate sufficient sales leads, provide adequate training to sales and marketing personnel and effectively manage a geographically dispersed sales and marketing team.

To commercialize our lead product candidate PF582, we have entered into a collaboration agreement with Hospira. If PF582 receives regulatory approval, Hospira is required to use commercially reasonable efforts to sell, market, and promote PF582 in certain major markets. For PF530 we will need to identify potential sales, marketing and distribution partners or establish our own internal sales force. In the future, we may choose to collaborate with other third parties that have direct sales forces and established distribution systems, either to augment our own sales force or in lieu of our own sales force. If we are unable to enter into such arrangements on acceptable terms or at all, we may not be able to successfully commercialize our product candidates. If we are not successful in commercializing our product candidates, either on our own or through collaborations with one or more third parties, our future product revenue will suffer and we would incur significant additional losses.

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

In the normal course of business, we periodically enter into academic, commercial and consulting agreements that contain indemnification provisions. With respect to our academic agreements, we may be required to indemnify the institution and related parties from losses arising from claims relating to the products, processes or services made, used, sold or performed pursuant to the agreements for which we have secured licenses, and from claims arising from our or our sublicensees’ exercise of rights under the agreement. With

-16-

Table of Contents

respect to commercial agreements entered into with our protein production customers, we typically provide indemnification for claims from third parties arising out of any potential intellectual property infringement associated with our P f ēnex Expression Technology ^® in the course of performing our services. With respect to our commercial agreements, the bulk of which are with contract manufacturers, we indemnify our vendors from third-party product liability claims which result from the production, use or consumption of the product, as well as for certain alleged infringements of any patent or other intellectual property right by a third party. With respect to consultants, we indemnify them from claims arising from the good faith performance of their services. In all of the above cases, we do not indemnify the parties for claims resulting from the negligence or willful misconduct of the indemnified party.

We maintain insurance coverage which we believe will limit our obligations under these indemnification provisions. However, should our obligation under an indemnification provision exceed applicable insurance coverage or if we were denied insurance coverage, our business, financial position and results of operations could be adversely affected and the market value of our common stock could decline.

We may have difficulty managing our growth and expanding our operations successfully.

As we advance our product candidates through the development process, we will need to expand our development, regulatory, manufacturing, quality, sales and marketing capabilities or contract with other organizations to provide these capabilities for us. As our operations expand, we expect that we will need to manage additional relationships with various collaborative partners, suppliers and other organizations.

As of December 31, 2014, we had 35 full-time employees. Our management and personnel, systems and facilities currently in place may not be adequate to support this future growth. Therefore, we will need to continue to expand our managerial, operational, finance and other resources to manage our operations and clinical trials, continue our development activities and commercialize our product candidates, if approved. In order to effectively execute our growth strategy, we will be required to:

Due to our limited financial resources and our limited experience in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. In addition, this expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our development and strategic objectives, or disrupt our operations, which could materially impact our business, revenue, and operating results.

The U.S. government holds certain intellectual property rights related to our Anthrax vaccine, Px563L and Malaria vaccine, Px533.

Although we have intellectual property related to expression of recombinant Protective Antigen in P. fluorescens , the U.S. government holds certain patents related to recombinant Protective Antigen, as well as

-17-

Table of Contents

certain rights to intellectual property related to other Px563L components such as adjuvants used to produce the final vaccine. We have rights to utilize this intellectual property held by the U.S. government by virtue of the fact that the development of our anthrax vaccine, Px563L, is funded by the Biomedical Advanced Research and Development Authority, or BARDA, within the Office of the Assistant Secretary for Preparedness and Response in the U.S. Department of Health and Human Services. In addition, the U.S. government holds certain intellectual property rights related to products developed under contracts (including “march-in” rights) with the U.S. government, which if exercised could materially impact our business, revenue and operating results with respect to Px563L and/or Px533.

Our contracts with the U.S. government, and our subcontracts with U.S. government contractors, require ongoing funding decisions by the U.S. government; reduced or discontinued funding of these contracts could cause our financial condition and operating results to suffer materially. Additionally, the amount we are paid under our government contract is based on negotiated rates for the time, resources and expenses required for us to perform the contract. If our actual costs exceed the negotiated rates, we may not be able to earn an adequate return or may incur a loss under the contract.

Development of our anthrax vaccine, Px563L, is funded by BARDA, and the development of our malaria vaccine, Px533, is funded by NIAID. The funding for government programs is subject to Congressional appropriations, often made on a fiscal year basis, even for programs designed to continue for several years. These appropriations can be subject to political considerations and stringent budgetary constraints. Additionally, our government-funded development contracts give the U.S. government the right, exercisable in its sole discretion, to extend this contract for successive option periods following a base period of performance. The value of the services to be performed during these option periods may constitute the majority of the total value of the underlying contract. If levels of government expenditures and authorizations for biodefense decrease or shift to programs in areas where we do not offer products or are not developing product candidates, or if the U.S. government otherwise declines to exercise its options under its contracts with us, our business, revenue and operating results would suffer.

Our current contracts with BARDA and NIAID are cost plus fixed-fee contracts and potential future contracts with the U.S. government may also be structured this way. Under our cost plus fixed-fee contract, we are allowed to recover our approved costs plus a fixed fee. The total price on a cost plus contract is based primarily on allowable costs incurred, but generally is subject to contract funding limitations. U.S. government regulations require us to notify our customer of any cost overruns or underruns on a cost plus contract. If we incur costs in excess of the funding limitation specified in the contract, we may not be able to recover those cost overruns.

Moreover, changes in U.S. government contracting policies could directly affect our financial performance. Factors that could materially adversely affect our U.S. government contracting business include:

-18-

Table of Contents

These or other factors could cause U.S. government departments or agencies to reduce their development funding or future purchases under contracts, to exercise their right to terminate contracts or fail to exercise their options to extend our contracts, any of which could have a material adverse effect on our business, financial condition, operating results and ability to meet our financial obligations.

Unfavorable provisions in government contracts, some of which are customary, may subject our business to material limitations, restrictions and uncertainties and may have a material adverse impact on our financial condition and operating results.

Government contracts contain provisions that give the U.S. government substantial rights and remedies, many of which are not typically found in commercial contracts, including provisions that allow the U.S. government to:

We may not have the right to prohibit the U.S. government from using certain technologies developed by us, and we may not be able to prohibit third party companies, including our competitors, from using those technologies in providing products and services to the U.S. government. The U.S. government generally takes the position that it has the right to royalty-free use of technologies that are developed under U.S. government contracts.

Generally, government contracts, including our contracts with BARDA and NIAID for the development of Px563L, contain provisions permitting unilateral termination or modification, in whole or in part, at the U.S.

-19-

Table of Contents

government’s convenience. Under general principles of government contracting law, if the U.S. government terminates a contract for convenience, the government contractor may recover only its incurred or committed costs, settlement expenses and profit on work completed prior to the termination. If the U.S. government terminates a contract for default, the government contractor is entitled to recover costs incurred and associated profits on accepted items only and may be liable for excess costs incurred by the government in procuring undelivered items from another source.

In addition, government contracts normally contain additional requirements that may increase our costs of doing business, reduce our profits, and expose us to liability for failure to comply with these terms and conditions. These requirements include, for example:

If we fail to maintain compliance with these requirements, we may be subject to potential contract or FCA liability and to termination of our contracts.

Our business is subject to audit by the U.S. government and a negative audit could adversely affect our business.

U.S. government agencies such as the Department of Health and Human Services, or HHS, and the Defense Contract Audit Agency, or the DCAA, routinely audit and investigate government contractors and recipients of federal grants. These agencies review a contractor’s performance under its contracts, cost structure and compliance with applicable laws, regulations and standards.

The HHS and the DCAA also review the adequacy of, and a contractor’s compliance with, its internal control systems and policies, including the contractor’s purchasing, property, estimating, compensation and management information systems. Any costs found to be improperly allocated to a specific contract will not be reimbursed, while such costs already reimbursed must be refunded. If an audit uncovers improper or illegal activities, we may be subject to civil and criminal penalties and administrative sanctions, including:

In addition, we could suffer serious reputational harm if allegations of impropriety were made against us, which could cause our stock price to decrease.

-20-

Table of Contents

The United States government’s determination to award a future contract or contract option may be challenged by an interested party, such as another bidder, at the United States Government Accountability Office, or the GAO, or in federal court. If such a challenge is successful, our government contracts or any future contract we may be awarded may be terminated.

The laws and regulations governing the procurement of goods and services by the U.S. government provide procedures by which other bidders and interested parties may challenge the award of a government contract. If we are awarded a government contract, such challenges or protests could be filed even if there are not any valid legal grounds on which to base the protest. If any such protests are filed, the government agency may decide to suspend our performance under the contract while such protests are being considered by the GAO or the applicable federal court, thus potentially delaying delivery of payment. In addition, we could be forced to expend considerable funds to defend any potential award. If a protest is successful, the government may be ordered to terminate any one or more of our contracts and reselect bids. The government agencies with which we have contracts could even be directed to award a potential contract to one of the other bidders.

Laws and regulations affecting government contracts make it more costly and difficult for us to successfully conduct our business.

We must comply with numerous laws and regulations relating to the formation, administration and performance of government contracts, which can make it more difficult for us to retain our rights under our government contracts, including our contracts with BARDA and NIAID. These laws and regulations affect how we conduct business with government agencies. Among the most significant government contracting regulations that affect our business are:

Any changes in applicable laws and regulations could restrict our ability to maintain our existing BARDA and NIAID contracts and obtain new contracts, which could limit our ability to conduct our business and materially adversely affect our results of operations.

Agreements with government agencies may lead to claims against us under the Federal False Claims Act, and these claims could result in substantial fines and other penalties.

The biopharmaceutical industry is, and in recent years has been, under heightened scrutiny as the subject of government investigations and enforcement actions. Our government contracts are subject to substantial financial penalties under the Federal Civil Monetary Penalties Act and the FCA. Under the FCA’s “whistleblower” provisions, private enforcement of fraud claims against businesses on behalf of the U.S. government has increased due in part to amendments to the FCA that encourage private individuals to sue on behalf of the government. These whistleblower suits, known as qui tam actions, may be filed by private individuals, including present and former employees. The FCA statute provides for treble damages and up to $11,000 per false claim. If our operations are found to be in violation of any of these laws, or any other governmental regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines, exclusion from the Medicare and Medicaid programs, and the curtailment or restructuring of our operations. Any penalties,

-21-

Table of Contents

damages, fines, exclusions, curtailment, or restructuring of our operations could adversely affect our ability to operate our business and our financial results.

If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of any future products we develop.

We face a risk of product liability as a result of the clinical testing of our product candidates and will face an even greater risk if we commercialize any products. For example, we may incur liability if any product we develop allegedly causes injury or is found to be otherwise unsuitable during product testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability and a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our products. Regardless of the merits or eventual outcome, liability claims may result in:

Our inability to obtain and maintain sufficient product liability insurance at an acceptable cost and scope of coverage to protect against potential product liability claims could impact the commercialization of PF582, PF530 and any future products we develop. We currently carry product liability insurance covering our clinical trials in the amount of $5.0 million in the aggregate. Although we maintain such insurance, any claim that may be brought against us could result in a court judgment or settlement that is in excess of the limits of our insurance coverage. Our insurance policies also have various exclusions and deductibles, and we may be subject to a product liability claim for which we have no coverage. We will have to pay any amounts awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts. Moreover, in the future, we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses. If and when we obtain approval for marketing PF582, PF530 or any other product candidates, we intend to expand our insurance coverage to include the sale of such products; however, we may be unable to obtain this liability insurance on commercially reasonable terms.

Our employees, independent contractors, principal investigators, CROs, consultants and collaborators may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements and insider trading.

We are exposed to the risk that our employees, independent contractors, principal investigators, third-party clinical research organizations, or CROs, consultants and collaborators may engage in fraudulent conduct or other illegal activity. Misconduct by these parties could include intentional, reckless and/or negligent conduct or unauthorized activities that violate: (1) regulations of the FDA and comparable foreign authorities, including

-22-

Table of Contents

those laws requiring the reporting of true, complete and accurate information to such authorities; (2) manufacturing standards; (3) federal and state healthcare fraud and abuse laws and regulations; or (4) laws that require the reporting of true and accurate financial information and data. In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive laws and regulations intended to prevent fraud, misconduct, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs and other business arrangements. These activities also include the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and serious harm to our reputation. We have adopted a Code of Ethics and Conduct, but it is not always possible to identify and deter misconduct by employees and other third parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting 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 civil, criminal and administrative penalties, damages, monetary fines, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, and curtailment of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

Our cash and cash equivalents and short term investments could be adversely affected if the financial institutions in which we hold our cash and cash equivalents and short term investments fail.

We regularly maintain cash balances at third-party financial institutions in excess of the Federal Deposit Insurance Corporation, or FDIC, insurance limit. While we monitor the cash balances in our accounts and adjust the balances as appropriate, these balances could be impacted, and there could be a material adverse effect on our business, if one or more of the financial institutions with which we deposit fails or is subject to other adverse conditions in the financial or credit markets. To date, we have experienced no loss or lack of access to our invested cash or cash equivalents; however, we can provide no assurance that access to our invested cash and cash equivalents will not be impacted by adverse conditions in the financial and credit markets.

Our business involves the use of hazardous materials and we, our collaboration partners, and our third party manufacturers and suppliers must comply with environmental laws and regulations, which can be expensive and restrict how we do business.

Our research and development and manufacturing activities and our third party manufacturers’ and suppliers’ activities involve the controlled storage, use and disposal of hazardous materials owned by us, including small quantities of acetonitrile, methanol, ethanol, ethidium bromide and compressed gases, and other hazardous compounds. We and our collaboration partners, manufacturers and suppliers are subject to laws and regulations governing the use, manufacture, storage, handling and disposal of these hazardous materials. In some cases, these hazardous materials and various wastes resulting from their use are stored at our and our manufacturers’ facilities pending their use and disposal. We cannot eliminate the risk of contamination, which could cause an interruption of our commercialization efforts, research and development efforts and business operations, environmental damage resulting in costly clean-up and liabilities under applicable laws and regulations governing the use, storage, handling and disposal of these materials and specified waste products. Although we believe that the safety procedures utilized by us and our third party manufacturers for handling and disposing of these materials generally comply with the standards prescribed by these laws and regulations, we cannot guarantee that this is the case or eliminate the risk of accidental contamination or injury from these materials. In such an event, we may be held liable for any resulting damages and such liability could exceed our resources and state or federal or other applicable authorities may curtail our use of certain materials and interrupt our business operations.

-23-

Table of Contents

We are also subject to numerous environmental, health and workplace safety laws and regulations, including those governing laboratory procedures, and the handling of biohazardous materials. Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of these materials, this insurance may not provide adequate coverage against potential liabilities. For claims not covered by workers’ compensation insurance, we also maintain an employer’s liability insurance policy in the amount of $1.0 million per occurrence and in the aggregate. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us.

Environmental laws and regulations are complex, change frequently and have tended to become more stringent. We cannot predict the impact of such changes and cannot be certain of our future compliance. Any inability to comply with environmental laws and regulations may adversely affect our business and operating results.

Risks Relating to our Reliance on Third Parties

We are substantially dependent on the expertise of Hospira and Strides Arcolab to develop and commercialize some of our product candidates. If we fail to maintain our current strategic relationship with Hospira and Strides Arcolab, our business, commercialization prospects and financial condition may be materially adversely affected.

Because we have limited or no capabilities for late-stage product development, manufacturing, sales, marketing and distribution, we may need to enter into alliances with other companies to develop our product candidates. For example, we have entered into agreements with Hospira and Strides Arcolab, pursuant to which we will transfer the development, manufacture and commercialization of some of our products.

Under the terms of the collaboration agreement, Hospira received exclusive licenses and rights and assumed responsibility for the manufacturing and commercialization of PF582, and is obligated to use commercially reasonable efforts to manufacture and commercialize PF582 in certain major markets globally. In consideration for the exclusive license and other rights contained in the collaboration agreement, we are eligible to receive up to $342 million in one-time payments, including a non-refundable payment of $51 million, which we received in March of 2015 upon receipt of antitrust approval, and up to $291 million upon the successful achievement of certain pre-commercial and commercial milestones, and double digit escalating royalties on annual sales of PF582. We will share the Phase 3 equivalence clinical trial costs with our share capped at $20 million, $10 million of which will be setoff as a credit against royalties payable to us, unless the collaboration agreement is terminated prior to such setoff. We will also share the costs of seeking regulatory approval of PF582 and a certain portion of other costs that are related to PF582 and that may begin after any filings for regulatory approval of PF582 would be made. The collaboration agreement also includes an obligation for each of us and Hospira to offer the other an opportunity to co-develop any other ophthalmic biological product that inhibits vascular endothelial growth factor A, or VEGF-A. The collaboration agreement permits either party to terminate the agreement for the other party’s uncured material breach or for certain insolvency events. In addition, Hospira may terminate the collaboration agreement upon the occurrence of certain clinical or regulatory events. If the collaboration agreement terminates, then the license granted to Hospira would end, and the licensed rights to PF582 would revert to us, subject to Hospira’s right to sell its remaining inventory over a certain period.

For the products included in the JDLA, Strides Arcolab is responsible for development expenses up to Phase 3, at which time we will share in expenses and revenue going forward. Additionally, we will transfer the development, manufacture and commercialization of the products to a joint venture company jointly owned by us and Strides Arcolab upon completion of Phase 1 trials.

The prospects for the product candidates depend on the expertise, development and commercial skills, and financial strength of Hospira and Strides Arcolab. Our collaborations with Hospira or Strides Arcolab may not be

-24-

Table of Contents

successful, and we may not realize the expected benefits from such collaborations, due to a number of important factors, including but not limited to the following:

A failure of Hospira or Strides Arcolab to successfully develop our product candidates which are covered by the collaboration, or commercialize such product candidates, or the termination of our agreement with Hospira or Strides Arcolab, as applicable, may have a material adverse effect on our business, results of operations and financial condition.

Our existing product development and/or commercialization arrangements, and any that we may enter into in the future, may not be successful, which could adversely affect our ability to develop and commercialize our product candidates.

We are a party to, and continue to seek additional, collaboration arrangements with other pharmaceutical companies for the development and/or commercialization of our current and future product candidates. In such alliances, we would expect our collaboration partners to provide substantial capabilities in clinical development, manufacturing, regulatory affairs, sales and marketing, both in the United States and internationally.

To the extent that we decide to enter into collaboration agreements, we will face significant competition in seeking appropriate collaboration partners. Any failure to meet our clinical milestones with respect to an unpartnered product candidate would make finding a collaboration partner more difficult. Moreover, collaboration arrangements are complex and time consuming to negotiate, document and implement, and we cannot guarantee that we can successfully maintain such relationships or that the terms of such arrangements will be favorable to us. If we fail to establish and implement collaboration or other alternative arrangements, the value of our business and operating results will be adversely affected.

We may not be successful in our efforts to establish, implement and maintain collaborations or other alternative arrangements if we choose to enter into such arrangements. The terms of any collaboration or other arrangements that we may establish may not be favorable to us. The management of collaborations may take significant time and resources that distract our management from other matters. Our ability to successfully collaborate with any future collaboration partners may be impaired by multiple factors including:

-25-

Table of Contents

Any such activities by our current or future collaboration partners could adversely affect us financially and could harm our business reputation.

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

We rely on CROs to conduct and oversee our planned clinical trials for our product candidates and other clinical trials for product candidates we are developing or may develop in the future. If our CROs do not successfully carry out their contractual duties, meet expected deadlines, or otherwise conduct the trials as required or comply with regulatory requirements, we and our collaboration partners may not be able to obtain regulatory approval for or commercialize our product candidates when expected or at all, and our business could be substantially harmed.

We will continue to rely upon medical institutions, clinical investigators and contract laboratories to conduct our trials in accordance with our clinical protocols and in accordance with applicable legal and regulatory requirements. These third parties play a significant role in the conduct of these trials and the subsequent collection and analysis of data from the clinical trials. These third parties are not our employees, and except for remedies available to us under our agreements with such third parties, there is no guarantee that any such third party will devote adequate time and resources to our clinical trial. If our CRO or any other third parties upon which we rely for administration and conduct of our clinical trials 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, or if they otherwise perform in a substandard manner, our clinical trials may be extended, delayed, suspended or terminated, and we may not be able to complete development of, obtain regulatory approval for, or successfully commercialize our product candidates. We plan to rely heavily on these third parties for the execution of clinical trials for products we are developing or may develop in the future, and

-26-

Table of Contents

will control only certain aspects of their activities. Nevertheless, we are responsible for ensuring that each of our clinical trials is conducted in accordance with the applicable protocol, legal, regulatory and scientific standards, and our reliance on our CRO does not relieve us of our regulatory responsibilities.

We, our CRO and our collaborators are required to comply with Good Clinical Practice, or GCP, which are regulations and guidelines enforced by regulatory authorities around the world for products in clinical development. Regulatory authorities enforce these GCP regulations through periodic inspections of clinical trial sponsors, principal investigators and clinical trial sites. If we, our CRO or our collaborators fail to comply with applicable GCP regulations, the clinical data generated in clinical trials may be deemed unreliable and submission of marketing applications may be delayed or the regulatory authorities may require us to perform additional clinical trials before approving marketing applications. We cannot assure that, upon inspection, a regulatory authority will determine that any of our clinical trials comply or complied with applicable GCP regulations. In addition, clinical trials must be conducted with product produced under current Good Manufacturing Practices, or cGMP, regulations, which are enforced by regulatory authorities. Any failure to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process. Moreover, our business may be implicated if our CRO violates federal or state fraud and abuse or false claims laws and regulations or healthcare privacy and security laws.

Phase 3 trials, such as the trial planned for PF582, require a substantial number of patients that can allow statistically significant results. Delays in site initiation or unexpectedly low patient enrollment rates may delay the results of the clinical trial. CROs may also generate higher costs than anticipated. As a result, our results of operations and the commercial prospects for our product candidates would be harmed, our costs could increase, and our ability to generate revenue could be delayed. Further, if our relationship with our CRO is terminated, we may be unable to enter into arrangements with an alternative CRO on commercially reasonable terms, or at all. Switching or adding CROs can involve substantial cost and require extensive management time and focus. In addition, there is a natural transition period when a new CRO commences work. As a result, delays may occur, which can materially impact our ability to meet our desired clinical development timelines. Although we carefully manage our relationship with our CROs, there can be no assurance that we will not encounter such challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, prospects, financial condition or results of operations.

We rely on third parties, and in some cases a single third-party, to manufacture nonclinical and clinical supplies of our product candidates and to store critical components of our product candidates for us. Our business could be harmed if those third parties fail to provide us with sufficient quantities of product candidates, or fail to do so at acceptable quality levels or prices.

We do not currently have the infrastructure or capability internally to manufacture supplies of our product candidates for use in clinical studies, and we lack the resources and the capability to manufacture any of our product candidates on a clinical or commercial scale. We rely on third party manufacturers, including our collaboration partners, Hospira and Strides Arcolab, to manufacture our product candidates for preclinical and clinical studies. Successfully transferring complicated manufacturing techniques to manufacturing organizations and scaling up these techniques for commercial quantities will be time consuming and we may not be able to achieve such transfer. Moreover, the market for contract manufacturing services for protein therapeutics is highly cyclical, with periods of relatively abundant capacity alternating with periods in which there is little available capacity. If our need for contract manufacturing services increases during a period of industry-wide production capacity shortage, we may not be able to produce our product candidates on a timely basis or on commercially viable terms. Although we generally do not begin a clinical study unless we believe we have a sufficient supply of a product candidate to complete such study, any significant delay or discontinuation in the supply of a product candidate for an ongoing clinical study due to the need to replace a third-party manufacturer could considerably delay completion of our clinical studies, product testing, and potential regulatory approval of our product candidates, which could harm our business and results of operations.

-27-

Table of Contents

Reliance on third party manufacturers entails additional risks, including reliance on the third party for regulatory compliance and quality assurance, the possible breach of the manufacturing agreement by the third party, and the possible termination or nonrenewal of the agreement by the third party at a time that is costly or inconvenient for us. In addition, third party manufacturers may not be able to comply with cGMP, or similar regulatory requirements outside the United States. Our failure, or the failure of our third party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of products, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our product candidates or any other product candidates or products that we may develop. Any failure or refusal to supply the components for our product candidates that are being developed could delay, prevent or impair clinical development or commercialization efforts. If our manufacturers were to breach or terminate their manufacturing arrangements with us, the development or commercialization of the affected products or product candidates could be delayed, which could have an adverse effect on our business. Any change in our manufacturers could be costly because the commercial terms of any new arrangement could be less favorable and because the expenses relating to the transfer of necessary technology and processes could be significant.

If any of our product candidates are approved, in order to produce the quantities necessary to meet anticipated market demand, any manufacturer that we engage may need to increase manufacturing capacity. If we or our manufacturers are unable to produce our product candidates in sufficient quantities to meet the requirements for the launch of these products or to meet future demand, our revenue and gross margins could be adversely affected. Although we believe that we and our manufacturers will not have any material supply issues, we cannot be certain that we will be able to obtain long-term supply arrangements for our product candidates or materials used to produce them on acceptable terms, if at all. If we are unable to arrange for third-party manufacturing, or to do so on commercially reasonable terms, we may not be able to complete development of our products or market them.

We also rely on third parties to store the PF582 master and working cell banks. We have one master cell bank and one working cell bank and believe we would have adequate backup should any cell bank be lost in a catastrophic event. However, it is possible that we could lose multiple cell banks and have our manufacturing severely impacted by the need to replace the cell banks, which could materially and adversely affect our business, financial condition and results of operations.

We rely on third party suppliers, and in some instances a single third-party supplier, for the manufacture and supply of certain materials in our protein production services, and these suppliers could cease to manufacture the materials, go out of business or otherwise not perform as anticipated.

We rely on third party suppliers for our protein production services and in some instances a single third-party supplier, for the manufacture and supply of certain materials. We currently rely, and expect to continue to rely, on a single-source supplier for the manufacture and supply of CRM197. To meet these demands, our supplier is in the process of increasing production capacity, and we also have established a repository in the United States that is capable of storing a safety supply of CRM197 and the CRM197 cell bank. Furthermore, we have taken steps to identify alternate sources of supply sufficient to support future needs; however, there may be delays in switching to these alternative suppliers if our contract with primary sources are terminated without notice. Regardless of the foregoing alternative measures, we cannot guarantee that we will have an adequate supply of CRM197. If we are unable to secure adequate quantities of CRM197 from our primary supplier, from potential secondary suppliers or from our safety supply, we may be required to identify additional suppliers. If we are required to engage additional suppliers, we may not be able to enter into an alternative supply arrangement on commercially reasonable terms, or at all. Even if we are able to identify additional suppliers and enter into agreements on commercially reasonable terms, we may incur delays associated with identifying and qualifying additional suppliers and negotiating the terms of any supply contracts. These delays could adversely impact our business and negatively affect profitability of our protein production services.

-28-

Table of Contents

We have entered into collaborations with third parties in connection with the development of certain of our product candidates. Even if we believe that the development of our technology and product candidates is promising, our partners may choose not to proceed with such development.

Our existing agreements with our collaboration partners, including our agreements with Hospira and Strides Arcolab, are generally subject to termination by the counterparty on short notice upon the occurrence of certain circumstances. Accordingly, even if we believe that the development of product candidates are worth pursuing, our partners may choose not to continue with such development. If any of our collaborations are terminated, we may be required to devote additional resources to the development of our product candidates or seek a new collaboration partner on short notice, and the terms of any additional collaboration or other arrangements that we establish may not be favorable to us.

We are also at risk that our collaborations or other arrangements may not be successful. Factors that may affect the success of our collaborations include the following:

If we cannot maintain successful collaborations, our business, financial condition and operating results may be adversely affected.

If we are unable to maintain our commercial supply agreements with key customers purchasing CRM197 or if third party distributors of our reagent proteins fail to perform as expected, sales revenue could decline.

We primarily sell CRM197 directly to biopharmaceutical companies and currently have several commercial supply agreements in place for long-term supply of CRM197. To establish and maintain relationships with customers, we believe we need to maintain adequate supplies of CRM197, remain price competitive, comply with regulatory regulations and provide high-quality products. If we are unable to establish and maintain arrangements for the sale of CRM197, our revenue and profits would decline.

Although we sell our protein reagents through multiple sales channels, including our ecommerce website, we also sell our protein reagents to some of our customers through third-party distributors. Many of such third parties also market and sell products from our competitors. Our third-party distributors may terminate their relationships with us at any time, or with short notice. Our future performance will also depend, in part, on our ability to attract additional third-party distributors that will be able to market protein reagents effectively, especially in markets in which we have not previously distributed our protein reagents. If our current third-party distributors fail to perform as expected, our revenue and results of operations could be harmed.

Risks Relating to Our Intellectual Property

Our collaboration partners may assert ownership or commercial rights to inventions we develop from our use of the materials which they provide to us, or otherwise arising from our collaboration.

We collaborate with several institutions with respect to research and development matters. Also, we rely on numerous third parties to provide us with materials that we use to develop our technology. If we cannot

-29-

Table of Contents

successfully negotiate sufficient ownership, licensing and/or commercial rights to any inventions that result from our use of any third party collaborator’s materials, or if disputes arise with respect to the intellectual property developed with the use of a collaborator’s materials, or data developed in a collaborator’s study, our ability to capitalize on the market potential of these inventions or developments may be limited or precluded altogether.

If our efforts to protect our intellectual property related to our platform technology and our current or future product candidates 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 current product candidates and our development programs. If we do not adequately protect our intellectual property, competitors may be able to use our technologies and erode or negate any competitive advantage we may have, which could harm our business and ability to achieve profitability. In particular, our success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries with respect to our platform and product candidates. However, we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. We may also fail to identify patentable aspects of our research and development before it is too late to obtain patent protection. Any disclosure to or misappropriation by third parties of our confidential proprietary information could enable competitors to quickly duplicate or surpass our technological achievements, eroding our competitive position in our market.

The patentability of inventions, and the validity, enforceability and scope of patents in the biotechnology and pharmaceutical industry involve complex legal and scientific questions and can be uncertain. This uncertainty includes changes to the patent laws through either legislative action to change statutory patent law or court action that may reinterpret existing law in ways affecting the scope or validity of issued patents. The patent applications that we own or license may fail to result in issued patents in the United States or foreign countries. There is a substantial amount of prior art in the biotechnology and pharmaceutical fields, including scientific publications, patents and patent applications. Our ability to obtain and maintain valid and enforceable patents depends on whether the differences between our technology and the prior art allow our technology to be patentable over the prior art. We may be unaware of certain prior art relating to our patent applications and patents, which could prevent a patent from issuing from a pending patent application, or result in an issued patent being invalidated. Even if the patents do successfully issue, third parties may challenge the validity, enforceability or scope of such issued patents or any other issued patents we own or license, which may result in such patents being narrowed, invalidated or held unenforceable.

Patents granted by the European Patent Office may be opposed by any person within nine months from the publication of their grant and, in addition, may be challenged before national courts at any time. Furthermore, even if they are unchallenged, our patents and patent applications may not adequately protect our intellectual property or prevent others from designing around our claims. If the breadth or strength of protection provided by the patents and patent applications we hold, license or pursue with respect to our product candidates is threatened, it could threaten our ability to commercialize our product candidates. In addition, recent changes to the patent laws of the United States provide additional procedures for third parties to challenge the validity of issued patents based on patent applications filed after March 15, 2013. If the breadth or strength of protection provided by the patents and patent applications we hold or pursue with respect to our current or future product candidates is challenged, then it could threaten our ability to commercialize our current or future product candidates, and could threaten our ability to prevent competitive products from being marketed. Further, if we encounter delays in our clinical trials, the period of time during which we could market our current or future product candidates under patent protection would be reduced. Since patent applications in the United States and most other countries are confidential for a period of time after filing, we cannot be certain that we were the first to either (i) file any patent application related to our product candidates or (ii) invent any of the inventions claimed in our patents or patent applications. Furthermore, for applications filed before March 16, 2013, or patents issuing from such applications, an interference proceeding can be provoked by a third party, or instituted by the United States Patent and Trademark Office, or USPTO, to determine who was the first to invent any of the

-30-

Table of Contents

subject matter covered by the patent claims of our applications and patents. As of March 16, 2013, the United States transitioned to a “first-to-file” system for deciding which party should be granted a patent when two or more patent applications are filed by different parties claiming the same invention. A third party that files a patent application in the USPTO before us could therefore be awarded a patent covering an invention of ours even if we had made the invention before it was made by the third party.

The change to “first-to-file” from “first-to-invent” is one of the changes to the patent laws of the United States resulting from the Leahy-Smith America Invents Act, or the Leahy-Smith Act, signed into law on September 16, 2011. Among some of the other significant changes to the patent laws are changes that limit where a patentee may file a patent infringement suit and provide opportunities for third parties to challenge any issued patent in the USPTO. It is not yet clear what, if any, impact the Leahy-Smith Act will have on the operation of our business. However, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business and financial condition.

Even where laws provide protection, costly and time-consuming litigation could be necessary to enforce and determine the scope of our proprietary rights, and the outcome of such litigation would be uncertain. Moreover, any actions we may bring to enforce our intellectual property against our competitors could provoke them to bring counterclaims against us, and some of our competitors have substantially greater intellectual property portfolios than we have.

If we are unable to protect the confidentiality of our trade secrets, the value of our technology could be materially adversely affected and our business would be harmed.

In addition to the protection afforded by patents, we also rely on trade secret protection and confidentiality agreements to protect proprietary know-how that may not be patentable, processes for which patents may be difficult to obtain or enforce and any other elements of our product development processes that involve proprietary know-how, information or technology that is not covered by patents.

As part of our efforts to protect our trade secrets and other confidential information, we require our employees, consultants, collaborators and advisors to execute confidentiality agreements upon the commencement of their relationships with us. These agreements require that all confidential information developed by the individual or made known to the individual by us during the course of the individual’s relationship with us be kept confidential and not disclosed to third parties. These agreements, however, may not provide us with adequate protection against improper use or disclosure of confidential information, and these agreements may be breached. Adequate remedies may not exist in the event of unauthorized use or disclosure of our confidential information. We also note in this respect that trade secret protection in foreign countries may not provide protection to the same extent as federal and state laws in the United States. A breach of confidentiality could significantly affect our competitive position. In addition, in some situations, these agreements may conflict with, or be subject to, the rights of third parties with whom our employees, consultants, collaborators or advisors have previous employment or consulting relationships. To the extent that our employees, consultants or contractors use any intellectual property owned by others in their work for us, disputes may arise as to the rights in any related or resulting know-how and inventions. Also, third parties, including our competitors, may independently develop substantially equivalent proprietary information and technologies or otherwise lawfully gain access to our trade secrets and other confidential information. In such a case, we would have no right to prevent such third parties from using such proprietary information or technologies to compete with us, which could harm our competitive position.

If we infringe or are alleged to infringe intellectual property rights of third parties, our business could be harmed.

Our research, development and commercialization activities may infringe or otherwise violate or be claimed to infringe or otherwise violate patents owned or controlled by other parties. Our competitors have developed

-31-

Table of Contents

large portfolios of patents and patent applications in fields relating to our business and it may not always be clear to industry participants, including us, which patents cover various types of products or methods of use. There may also be patent applications that have been filed but not published that, when issued as patents, could be asserted against us. The coverage of patents is subject to interpretation by the courts, and the interpretation is not always uniform. If we are sued for patent infringement, we would need to demonstrate that our product candidates, products or methods either do not infringe the patent claims of the relevant patent or that the patent claims are invalid, and we may not be able to do this. Proving that a patent is invalid is difficult. For example, in the United States, proving invalidity requires a showing of clear and convincing evidence to overcome the presumption of validity enjoyed by issued patents. Also in proceedings before courts in Europe, the burden of proving invalidity of the patent usually rests on the party alleging invalidity. Third parties could bring claims against us that would cause us to incur substantial expenses and, if successful against us, could cause us to pay substantial damages. Further, if a patent infringement suit were brought against us, we could be forced to stop or delay research, development, manufacturing or sales of the product or product candidate that is the subject of the suit.

As a result of patent infringement claims, or to avoid potential claims, we may choose or be required to seek licenses from third parties. These licenses may not be available on acceptable terms, or at all. Even if we are able to obtain a license, the license would likely obligate us to pay license fees or royalties or both, and the rights granted to us might be nonexclusive, which could result in our competitors gaining access to the same intellectual property. Ultimately, we could be prevented from commercializing a product, or be forced to cease some aspect of our business operations, if, as a result of actual or threatened patent infringement claims, we are unable to enter into licenses on acceptable terms.

There has been substantial litigation and other proceedings regarding patent and other intellectual property rights in the pharmaceutical industry. In addition to infringement claims against us, we may become a party to other patent litigation and other proceedings, including interference, derivation or post-grant proceedings declared or granted by the USPTO and similar proceedings in foreign countries, regarding intellectual property rights with respect to our current or future products. Third parties may submit applications for patent term extensions in the United States and/or supplementary protection certificates in the European Union member States seeking to extend certain patent protection which, if approved, may interfere with or delay the launch of one or more of our biosimilar or vaccine products. The cost to us of any patent litigation or other proceeding, even if resolved in our favor, could be substantial. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. Patent litigation and other proceedings may also absorb significant management time. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could impair our ability to compete in the marketplace. The occurrence of any of the foregoing could have a material adverse effect on our business, financial condition or results of operations.

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

Competitors may infringe our intellectual property, including our patents or the patents of our licensors. In addition, one or more of our third party collaborators may have submitted, or may in the future submit, a patent application to the USPTO without naming a lawful inventor that developed the subject matter in whole or in part while under an obligation to execute an assignment of rights to us. As a result, we may be required to file infringement or inventorship claims to stop third party infringement, unauthorized use, or to correct inventorship. This can be expensive, particularly for a company of our size, and time-consuming. Any claims that we assert against perceived infringers could also provoke these parties to assert counterclaims against us alleging that we infringe their intellectual property rights. In addition, in an infringement proceeding, a court may decide that a patent of ours 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 patent claims do not cover its technology or that the factors necessary to grant an injunction against an infringer are not satisfied.

-32-

Table of Contents

An adverse determination of any litigation or other proceedings could put one or more of our patents at risk of being invalidated, held unenforceable or interpreted narrowly and could put our patent applications at risk of not issuing.

Interference, derivation or other proceedings brought at the USPTO or any foreign patent authority may be necessary to determine the priority or patentability of inventions with respect to our patent applications or those of our licensors or collaborators. Litigation or USPTO proceedings brought by us may fail. An unfavorable outcome in any such proceedings could require us to cease using the related technology or to attempt to license rights to it from the prevailing party, or could cause us to lose valuable intellectual property rights. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms, if any license is offered at all. Even if we are successful, domestic or foreign litigation or USPTO or foreign patent office proceedings may result in substantial costs and distraction to our management. We may not be able, alone or with our licensors or collaborators, to prevent misappropriation of our trade secrets, confidential information or proprietary rights, particularly in countries where the laws may not protect such rights as fully as in the United States.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation or other proceedings, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation or proceedings. In addition, during the course of this kind of litigation or proceedings, there could be public announcements of the results of hearings, motions or other interim proceedings or developments or public access to related documents. If investors perceive these results to be negative, the market price for our common stock could be significantly harmed.

We may not be able to globally protect our intellectual property rights.

Filing, prosecuting and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the United States can be less extensive than those in the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States and in some cases may even force us to grant a compulsory license to competitors or other third parties. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and further, may export otherwise infringing products to territories where we have patent protection, but enforcement is not as strong as that in the United States. These products may compete with our products and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents and other intellectual property protection, particularly those relating to biopharmaceuticals, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

In addition, our ability to protect and enforce our intellectual property rights may be adversely affected by unforeseen changes in domestic and foreign intellectual property laws.

-33-

Table of Contents

Obtaining and maintaining patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees, renewal fees, annuity fees and various other governmental fees on patents and/or applications will be due to be paid to the USPTO and various governmental patent agencies outside of the United States in several stages over the lifetime of the patents and/or applications. The USPTO and various non-U.S. governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. In many cases, an inadvertent lapse can be cured by payment of a late fee or by other means in accordance with the applicable rules. However, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. In such an event, our competitors might be able to use our technologies and this circumstance would have a material adverse effect on our business.

We may be subject to claims that our employees or consultants have wrongfully used or disclosed alleged trade secrets of former or other employers.

Many of our employees and consultants, including our senior management, have been employed or retained by other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our employees and consultants do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these employees or consultants have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such employee’s or consultant’s former or other employer. We are not aware of any material threatened or pending claims related to these matters, but in the future litigation may be necessary to defend against such claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management.

Risks Related to Government Regulation

The approval processes of the FDA, EMA, and comparable foreign authorities are lengthy, time consuming and inherently unpredictable, and if we and our collaborators are ultimately unable to obtain regulatory approval for our product candidates, our business will be substantially harmed.

The research, development, testing, manufacturing, labeling, packaging, approval, promotion, advertising, storage, marketing, distribution, post-approval monitoring and reporting, and export and import of drug and biologic products are subject to extensive regulation by the FDA and other regulatory authorities in the United States, by the EMA and EEA Competent Authorities in the EEA, and by other regulatory authorities in other countries, which regulations differ from country to country. Neither we nor any collaboration partner is permitted to market PF582, PF530, or any future product candidates in the United States until approval from the FDA is received, or in the EEA until we receive EU Commission or EEA Competent Authority approvals are received. The time required to obtain approval from regulatory authorities is unpredictable, typically takes many years following the commencement of clinical trials, and depends upon numerous factors, including the substantial discretion of such regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate’s clinical development and may vary among jurisdictions, which may cause delays in the approval or the decision not to approve an application. We and our collaboration partners have not obtained regulatory approval for any product candidate and 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 regulatory approval.

Applications for our product candidates could fail to receive regulatory approval for many reasons, including but not limited to the following:

-34-

Table of Contents

This lengthy approval process as well as the unpredictability of future clinical trial results may result in our failing to obtain regulatory approval to market PF582, PF530, or any other product candidates, which would significantly harm our business, results of operations and prospects. Moreover, any delays in the commencement or completion of clinical testing could significantly impact our product development costs and could result in the need for additional financing.

In addition, even if we or our collaborators were to obtain approval, regulatory authorities may approve any of our product candidates for fewer or more limited indications than requested, may grant approval contingent on the performance of costly post-marketing clinical trials, or may approve a product candidate with a label that does not include the labeling claims necessary or desirable for the successful commercialization of that product candidate. Any of the foregoing scenarios could materially harm the commercial prospects for our product candidates.

If we or our collaborators fail to obtain approval for our two most advanced biosimilar product candidates or if our two most advanced biosimilar product candidates are not commercially successful, we may have to curtail our product development programs and our business would be materially harmed.

We have invested a significant portion of our time, financial resources and efforts in the development of our two most advanced biosimilar product candidates, PF582 and PF530. As of December 31, 2014, we have invested approximately $7.8 million in the development of these product candidates. The clinical and commercial success of our product candidates will depend on a number of factors, including the following:

-35-

Table of Contents

If we and our collaboration partners are unable to obtain regulatory approval for one or both of these product candidates in a timely manner or at all, we may never realize revenue from these products and we may have to curtail our other product development programs. As a result, our business, financial condition and results of operations would be materially harmed.

Our ability to market our products in the United States may be significantly delayed or prevented by the BPCIA patent dispute resolution mechanism.

The Biologics Price Competition and Innovation Act of 2009, Title VII, Subtitle A of the Patent Protection and Affordable Care Act, Pub.L.No.111-148, 124 Stat.119, Sections 7001-02 signed into law March 23, 2010, and codified in 42 U.S.C. §262, or the BPCIA, created an elaborate and complex patent dispute resolution mechanism for biosimilars that could prevent us from launching our product candidates in the United States or could substantially delay such launches. The BPCIA mechanism required for 351(k) biosimilar applicants may pose greater risk as compared to the litigation risk to which we might be exposed under a traditional 351(a) BLA regulatory pathway.

The BPCIA mandates patent disclosure and briefing requirements that are demanding, time-sensitive and, to date, untested. The following is an overview of the patent exchange and patent briefing procedures required by the BPCIA:

-36-

Table of Contents

Biosimilar companies such as ours have the option of applying for U.S. regulatory approval for our products under either a traditional 351(a) BLA approval route, or under the recently enacted streamlined 351(k) approval route established by the BPCIA. The factors underpinning such a decision are extremely complex and involve, among other things, balancing legal risk (in terms of, e.g., the degree and timing of exposure to potential patent litigation by the originator) versus regulatory risks (in terms of, e.g., the development costs and the differing scope of regulatory approval that may be afforded under 351(a) versus 351(k)).

A significant legal risk in pursuing regulatory approval under the 351(k) regulatory approval route is that the above-summarized patent exchange process established by the BPCIA could result in the initiation of patent infringement litigation prior to FDA approval of a 351(k) application, and such litigation could result in blocking the market entry of our products. In particular, while the 351(k) route is more attractive to us (versus 351(a)) for reasons related to development time and costs and the potential broader scope of eventual regulatory approval for our proposed biosimilar candidates, the countervailing risk in such a regulatory choice is that the complex patent exchange process mandated by the BPCIA could ultimately prevent or substantially delay us from launching our products in the United States.

Moreover, the disclosure process required in Step 1 of the process outlined above, which requires the biosimilar applicant to disclose not only the regulatory application but also the applicant’s manufacturing process, has the potential to afford originators an easier path than traditional infringement litigation for developing any factual grounds they may require to support allegations of infringement. The rules established in the BPCIA’s patent dispute procedures (versus the rules governing traditional patent infringement litigation) place biosimilar firms at a significant disadvantage by affording originators a much easier mechanism for factual discovery, thereby increasing the risk that a biosimilar product could be blocked from the market more quickly than under traditional patent infringement litigation processes.

Preparing for and conducting the patent exchange, briefing and negotiation process outlined above will require extraordinarily sophisticated legal counseling and extensive planning, all under extremely tight deadlines. Moreover, it may be difficult for us to secure such legal support if large, well-funded originators have already

-37-

Table of Contents

entered into engagements with highly qualified law firms or if the most highly qualified law firms choose not to represent biosimilar applicants due to their long standing relationships with originators. Furthermore, we could be at a serious disadvantage in this process as an originator company, such as competitors may be able to apply substantially greater legal and financial resources to this process than we could.

We are aware that some biosimilar companies, namely Sandoz and Celltrion, Inc. have engaged in legal challenges against originators to establish their right to bring declaratory judgment actions against such originators outside the complex framework of the BPCIA patent exchange rules in order to challenge the validity of the originators’ patents prior to the filing of any biosimilar regulatory application. For example, in the Sandoz case against the originator Amgen (relating to Sandoz’ proposed etanercept (Enbrel) biosimilar) the federal district court ruled that Sandoz did not have the right to bring a declaratory judgment action against Amgen to challenge the validity of certain Amgen-controlled patents directed to Enbrel, but instead determined that Sandoz must use the patent exchange mechanism established in the BPCIA. Sandoz appealed this decision to the United States Court of Appeals for the Federal Circuit, and on December 5, 2014 the Federal Circuit Court ruled that Sandoz had not met the legal requirements to pursue a declaratory judgment action against Amgen. The Federal Circuit court did not address whether the patent resolution mechanism established in the BPCIA would preclude Sandoz from filing its declaratory judgment action against Amgen if and when it files an FDA application under the BCPIA for its etanercept biosimilar.

In October 2014, Amgen filed suit in federal district court against Sandoz alleging that Sandoz unlawfully refused to follow the patent resolution provisions of the BPCIA in connection with Sandoz’ July 2014 regulatory approval application under 351(k) for its Neupogen (filgrastim) biosimilar, Zarxio. Amgen is seeking declaratory and injunctive relief. In October 2014 Amgen also filed a Citizen’s Petition with the FDA asking that the FDA require biosimilar applicants to comply with the BCPIA by providing to the reference product sponsor a copy of the biosimilar application accepted for review, together with information that fully describes the manufacture of the proposed biosimilar product, within 20 days after being informed by the FDA that the biosimilar application has been accepted for review. On March 19, 2015, the district court refused Amgen’s request to enjoin Sandoz’ launch of Zarxio and ruled that the patent resolution provisions of the BPCIA (summarized above in paragraphs 1 through 8) are optional insofar as it is permissible for a 351(k) applicant to decide not to provide its BLA and/or manufacturing information to the originator. The court also held that a biosimilar applicant need not wait until it receives BLA approval to provide the 180 prior day notice of commercial marketing set forth in the BPCIA provisions (see paragraph 8 above), but instead may provide such notice to the originator, if at all, prior to receiving FDA approval. On March 26, 2015, the FDA denied Amgen’s Citizen’s Petition.

While the ability to file declaratory judgment actions outside the framework of the BPCIA, or to treat the patent resolution mechanism of this framework as optional, may be attractive to us for addressing and resolving patent infringement risks prior to the expenditure of substantial development and regulatory costs, we see the potential for substantial risk that the federal appeals court could reverse the district court’s decision in the Amgen v. Sandoz case and instead rule that the patent resolution framework of the BCPIA is mandatory, and that Sandoz violated this framework by refusing to follow it. These pending court cases may ultimately require biosimilar applicants to test (or defend against) originator patents only in the BPCIA process, after they have filed for regulatory approval under 351(k). We believe this required order of events may expose biosimilar applicants to more patent litigation risk than they might otherwise be exposed to in litigation conducted outside the BPCIA framework, such as (i) under a regulatory application that we might choose to pursue under 351(a), where an originator would not be able to use the BPCIA procedures to potentially block the launch of a biosimilar product candidate; or (ii) under a 351(k) application in which federal court rulings may conclude it is permissible for biosimilar applicants to “opt out” of the BCPIA patent resolution mechanism, as has Sandoz in its 351(k) application for Zarxio.

Whether courts will ultimately view the BPCIA process as the sole and mandatory framework for a biosimilar entity and the originator to identify and potentially initiate patent litigation prior to launch of a biosimilar product remains highly uncertain. We see the potential for substantial risk that a final outcome to that

-38-

Table of Contents

effect in the Sandoz and Celltrion cases could increase patent infringement risks for companies, including ours, seeking to introduce biosimilar versions of originator products.

If we file a 351(k) regulatory approval application for one or more of our products, we may consider it necessary or advisable to adopt the strategy of selecting one or more patents of the originator to litigate in the above described BPCIA process (for example in steps 3 and 7, of the process, as outlined above), either to assert our non-infringement of such patents or to challenge their validity; but we may ultimately not be successful in that strategy and could be prevented from marketing the product in the United States.

Under the complex, untested and uncertain rules of the BPCIA patent provisions, coupled with the inherent uncertainty surrounding the legal interpretation of any originator patents that might be asserted against us in this new process, we see substantial risk that the BPCIA process may significantly delay or defeat our ability to market our products in the United States.

Clinical drug development involves a lengthy and expensive process with an uncertain outcome, and results of earlier studies and trials may not be predictive of future trial results.

Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Furthermore, we rely on our collaborators, CROs, and clinical trial sites to ensure the proper and timely conduct of our clinical trials for our product candidates. While we have agreements governing the committed activities of our collaborators and CROs, we have limited influence over their actual performance. A failure of one or more clinical trials can occur at any time during the trial process. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. Product candidates that have shown promising results in early studies may still suffer significant setbacks in subsequent clinical studies. For example, the results generated to date in clinical trials for PF582 do not ensure that later clinical trials, including our planned Phase 3 clinical trial for PF582, will demonstrate similar results. There is a high failure rate for drugs and biologics proceeding through clinical studies, and product candidates in later stages of clinical trials may fail to show the desired safety and efficacy despite having progressed through preclinical studies and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier clinical trials, and we cannot be certain that we will not face similar setbacks. Even if the clinical trials for our product candidates are completed, nonclinical and clinical data are often susceptible to varying interpretations and analyses, and the results may not be sufficient to obtain regulatory approval for our product candidates.

We have in the past and may in the future experience delays in ongoing clinical trials for our product candidates, and we do not know whether future clinical trials, if any, will begin on time, need to be redesigned, enroll an adequate number of patients on time or be completed on schedule, if at all. The commencement or completion of clinical trials can be delayed or aborted for a variety of reasons, including delay or failure to:

-39-

Table of Contents

Patient enrollment is a significant factor in the timing of clinical trials and is affected by many factors, including the size and nature of the patient population, the proximity of patients to clinical sites, the eligibility criteria for the trial, the design of the clinical trial, competing clinical trials and clinicians’ and patients’ perceptions as to the potential advantages of the drug being studied in relation to other available therapies, including any new drugs or treatments that may be approved for the indications we are investigating.

We could also encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions in which such trials are being conducted, by the data safety monitoring board, for such trial or by the FDA or other regulatory authorities. Such authorities may suspend or terminate a clinical trial due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial.

If we or our collaborators experience delays in the completion of, or termination of, any clinical trial of our product candidates, the commercial prospects of our product candidates may be harmed, and our ability to generate product revenue from any of these product candidates will be delayed. In addition, any delays in completing clinical trials for our product candidates will increase our costs, slow down our product candidate development and approval process and jeopardize our ability to commence product sales and generate revenue. Any of these occurrences may significantly harm our business, financial condition and prospects. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates.

Even if PF582, PF530 or any future product candidates obtain regulatory approval, they may never achieve market acceptance or commercial success.

Even if we or our collaboration partners’ obtain FDA or other regulatory approvals, PF582, PF530 or any future product candidates may not achieve market acceptance among physicians and patients, and may not be commercially successful.

The degree and rate of market acceptance of PF582, PF530 or any future product candidates for which we receive approval depends on a number of factors, including:

-40-

Table of Contents

Any failure by our product candidates that obtain regulatory approval to achieve market acceptance or commercial success would materially adversely affect our results of operations and delay, prevent or limit our ability to generate revenue and continue our business.

The development, manufacture and commercialization of biosimilar products poses unique risks, and our failure to successfully introduce biosimilar products could have a negative impact on our business and future operating results.

We are actively working to develop multiple biosimilar products, including our two most advanced biosimilar product candidates, PF582 and PF530. The cost to develop each biosimilar product candidate could vary significantly and is highly dependent on the specific compound and the amount and type of clinical work that will be necessary for regulatory approval. There can be no assurance that our clinical work will be successful, or that regulatory authorities will not require additional clinical development beyond that which we have planned. Additionally, we may enter into alliances and collaborations to fund biosimilar research and development activities, and the success of any such biosimilar program may depend on our ability to realize the benefits under such arrangements. Due to events beyond our control or the risks identified herein, we may be unable to fund all or some of our internal biosimilar research and development initiatives, which would have an adverse impact on our strategy and growth initiatives.

We intend to pursue market authorization globally. The European Union has, since October 2005, had a regulatory framework for the approval of biosimilar products and, as of December 31, 2014, has approved more than 20 biosimilar products. In the United States an abbreviated pathway for approval of biosimilar products was established by the Biologics Price Competition and Innovation Act of 2009, or BPCIA, enacted on March 23, 2010, as part of the Patient Protection and Affordable Care Act. The BPCIA established this abbreviated pathway under section 351(k) of the Public Health Service Act, or PHSA. Subsequent to the enactment of the BPCIA the FDA issued draft guidance regarding the demonstration of biosimilarity as well as the submission and review of biosimilar applications. However, the first biosimilar was just approved by FDA on March 6, 2015. Moreover, market acceptance of biosimilar products in the U.S. is unclear. Numerous states are considering or have already enacted laws that regulate or restrict the substitution by state pharmacies of biosimilars for biological products already licensed by the FDA pursuant to BLAs, or “reference products.” Market success of biosimilar products will depend on demonstrating to patients, physicians, payors, and relevant authorities that such products are safe and efficacious compared to other existing products.

We will continue to analyze and incorporate into our biosimilar development plans any final regulations issued by the FDA, pharmacy substitution policies enacted by state governments, and other applicable requirements established by relevant authorities. The costs of development and approval, along with the probability of success for our biosimilar product candidates, will be dependent upon application of any laws and regulations issued by the relevant regulatory authorities.

Biosimilar products may also be subject to extensive patent clearances and patent infringement litigation, which will likely delay and could prevent the commercial launch of a product. Moreover, the BPCIA prohibits

-41-

Table of Contents

the FDA from accepting an application for a biosimilar candidate to a reference product within four years of the reference product’s licensure by the FDA. In addition, the BPCIA provides innovative biologics with twelve years of exclusivity from the date of their licensure, during which time the FDA cannot approve any application for a biosimilar candidate to the reference product. For example, the FDA may not be able to approve any application that we or our collaborators submit for PF582 until twelve years after the original BLA for Lucentis was approved. However, in his proposed budget for fiscal year 2014, President Obama proposed to cut this twelve-year period of exclusivity down to seven years. He also proposed to prohibit additional periods of exclusivity due to minor changes in product formulations, a practice often referred to as “evergreening.” It is possible that Congress may take these or other measures to reduce or eliminate periods of exclusivity.

The BPCIA is complex and only beginning to be interpreted and implemented by the FDA. As a result, its ultimate impact, implementation, and meaning is subject to significant uncertainty. Future implementation decisions by the FDA could result in delays in the development or commercialization of our product candidates or increased costs to assure regulatory compliance, and could adversely affect our operating results by restricting or significantly delaying our ability to market new biosimilar products.

In the EEA, holders of marketing authorizations of reference products (authorized under the centralized procedure after November 20, 2005, or under the Decentralized, Mutual Recognition and national procedures, after October 30, 2005) enjoy eight years of data exclusivity during which a generic or biosimilar marketing authorization applicant cannot rely on the preclinical and clinical data included in the reference product’s dossier, and ten years of marketing exclusivity during which a generic or biosimilar of the reference product cannot be placed in the EEA market. The marketing exclusivity period can be extended one additional year (to eleven years) if a second indication of the reference product with significant clinical benefit is approved during the eight year data exclusivity period. The data and marketing exclusivity periods start from the date of the initial authorization, which for reference medicinal products authorized through the Centralized Procedure is the date of notification of the marketing authorization decision to the marketing authorization holder of the reference product notification of the marketing authorization decision to the marketing authorization holder of the reference product. Lucentis was granted a marketing authorization by the EU Commission through the EU centralized procedure on January 22, 2007.

We may rely on the Animal Rule in conducting trials, which could be time consuming and expensive.

To obtain FDA approval for our vaccine candidate Px563L, we may obtain clinical data from trials in healthy human subjects that demonstrate adequate safety, and efficacy data from adequate and well-controlled animal studies under regulations issued by the FDA in 2002, often referred to as the “Animal Rule.” Among other requirements, the animal studies must establish that the drug or biological product is reasonably likely to produce clinical benefits in humans. If we use this approach we may not be able to sufficiently demonstrate this correlation to the satisfaction of the FDA, as these corollaries are difficult to establish and are often unclear. Because the FDA must agree that data derived from animal studies may be extrapolated to establish safety and effectiveness in humans, seeking approval under the Animal Rule may add significant time, complexity and uncertainty to the testing and approval process. The FDA may decide that our data are insufficient for approval and require additional preclinical, clinical or other studies, refuse to approve Px563L, or place restrictions on our ability to commercialize the products. In addition, products approved under the Animal Rule are subject to additional requirements including post-marketing study requirements, restrictions imposed on marketing or distribution or requirements to provide information to patients. Further, regulatory authorities in other countries have not, at this time, established an “Animal Rule” equivalent, and consequently there can be no assurance that we will be able to make a submission for marketing approval in foreign countries based on such animal data.

Additionally, few facilities in the U.S. and internationally may have the capability to test animals involving exposure to anthrax or otherwise assist us in qualifying the requisite animal models, and we must compete with other companies for access to this limited pool of highly specialized resources. We therefore may not be able to secure contracts to conduct the testing in a predictable timeframe or at all.

-42-

Table of Contents

If we and our collaboration partners are not able to demonstrate biosimilarity of our biosimilar product candidates to the satisfaction of regulatory authorities, we will not obtain regulatory approval for commercial sale of our biosimilar product candidates and our future results of operations would be adversely affected.

Our future results of operations depend, to a significant degree, on our and our collaboration partners’ ability to obtain regulatory approval for and commercialize our proposed biosimilar products. To obtain regulatory approval for the commercial sale of these product candidates, we will be required to demonstrate to the satisfaction of regulatory authorities, among other things, that our proposed biosimilar products are highly similar to biological products already licensed by the FDA pursuant to Biologic License Applications, or BLAs, notwithstanding minor differences in clinically inactive components, and that they have no clinically meaningful differences as compared to the marketed biological products in terms of the safety, purity and potency of the products. In the EEA, the similar nature of a biosimilar and a reference product is demonstrated by comprehensive comparability studies covering quality, biological activity, safety and efficacy. For example, a determination of biosimilarity for PF582 will be based on our demonstration of its high similarity to Lucentis.

In addition, the FDA may determine that a proposed biosimilar product is “interchangeable” with a reference product, meaning that the biosimilar product may be substituted for the reference product without the intervention of the health care provider who prescribed the reference product, if the application includes sufficient information to show that the product is biosimilar to the reference product and that it can be expected to produce the same clinical result as the reference product in any given patient. If the biosimilar product may be administered more than once to a patient, the applicant must demonstrate that the risk in terms of safety or diminished efficacy of alternating or switching between the biosimilar and reference product is not greater than the risk of using the reference product without such alternation or switch. To make a final determination of biosimilarity or interchangeability, regulatory authorities may require additional confirmatory information beyond what we and our collaboration partners plan to initially submit in our applications for approval, such as more in-depth analytical characterization, animal testing, or further clinical studies. Provision of sufficient information for approval may prove difficult and expensive. We cannot predict whether any of our biosimilar product candidates will meet regulatory authority requirements for approval as a biosimilar or interchangeable product.

In the event that regulatory authorities require us to conduct additional clinical trials or other lengthy processes, the commercialization of our proposed biosimilar products could be delayed or prevented. Delays in the commercialization of, or the inability to obtain regulatory approval for, these products could adversely affect our operating results by restricting or significantly delaying our introduction of new biosimilars.

If other biosimilars of Lucentis or Betaseron are approved and successfully commercialized before PF582 or PF530, our business would suffer.

Other companies may seek approval to manufacture and market biosimilar versions of Lucentis or Betaseron. If other biosimilars of Lucentis or Betaseron are approved and successfully commercialized before PF582 or PF530, we may never achieve significant market share for PF582 and PF530, our revenue would be reduced and, as a result, our business, prospects and financial condition could suffer. In addition, the first biosimilar determined to be interchangeable with a particular reference product for any condition of use is eligible for a period of market exclusivity that delays an FDA determination that a second or subsequent biosimilar product is interchangeable with that reference product for any condition of use until the earlier of: (1) one year after the first commercial marketing of the first interchangeable product; (2) 18 months after resolution of a patent infringement suit instituted under 42 U.S.C. § 262(l)(6) against the applicant that submitted the application for the first interchangeable product, based on a final court decision regarding all of the patents in the litigation or dismissal of the litigation with or without prejudice; (3) 42 months after approval of the first interchangeable product, if a patent infringement suit instituted under 42 U.S.C. § 262(l)(6) against the applicant that submitted the application for the first interchangeable product is still ongoing; or (4) 18 months after approval of the first interchangeable product if the applicant that submitted the application for the first

-43-

Table of Contents

interchangeable product has not been sued under 42 U.S.C. § 262(l)(6). A determination that another company’s product is interchangeable with Lucentis or Betaseron prior to approval of PF582 or PF530 may therefore delay the potential determination that PF582 or PF530 is interchangeable with the reference product, which may materially adversely affect our results of operations and delay, prevent or limit our ability to generate revenue.

Failure to obtain regulatory approval in each regulatory jurisdiction would prevent us and our collaboration partners from marketing our products to a larger patient population and reduce our commercial opportunities.

In order to market our products in the European Union, the United States and other jurisdictions, we or our collaboration partners must obtain separate regulatory approvals and comply with numerous and varying regulatory requirements. The European Medicines Agency is responsible for the centralized procedure for human medicines. This procedure results in a single marketing authorization that is valid in all European Union countries, as well as in Iceland, Liechtenstein and Norway. The time required to obtain approval abroad may differ from that required to obtain FDA approval. The foreign regulatory approval process may include all of the risks associated with obtaining FDA approval and we may not obtain foreign regulatory approvals on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. We may not be able to file for regulatory approvals and may not receive necessary approvals to commercialize our products within the United States or in any market outside the United States. Failure to obtain these approvals would materially and adversely affect our business, financial condition and results of operations.

Even if we and our collaboration partners obtain regulatory approvals for our product candidates, we will be subject to ongoing regulatory review.

Even if we and our collaboration partners obtain regulatory approval for our product candidates, any products we develop will be subject to ongoing regulatory review with respect to manufacturing, labeling, packaging, storage, advertising, promotion, sampling, record-keeping, conduct of post-marketing studies, and submission of safety, efficacy, and other post-market information, including both federal and state requirements in the United States and requirements of comparable foreign regulatory authorities. Manufacturers and manufacturers’ facilities are required to comply with extensive FDA and comparable foreign regulatory authority requirements, including ensuring that quality control and manufacturing procedures conform to cGMP. As such, we and our contract manufacturers will be subject to continual and possibly unannounced review and inspections by the regulatory authorities governing the markets in which we wish to sell our products. Accordingly, we and others with whom we work must continue to expend time, money, and effort in all areas of regulatory compliance, including manufacturing, production, and quality control.

Any regulatory approvals that we and our collaboration partners receive for our product candidates may be subject to limitations on the approved indicated uses for which the product may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing testing, including Phase 4 trials, and surveillance to monitor the safety and efficacy or the safety, purity, and potency of the product candidate. We will be required to immediately report any serious and unexpected adverse events and certain quality or production problems with our products to regulatory authorities along with other periodic reports. Any new legislation addressing drug or biologic product safety issues could result in delays in product development or commercialization, or increased costs to assure compliance. We and our collaboration partners will have to comply with requirements concerning advertising and promotion for our products. Promotional communications with respect to prescription drug and biologic products are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the product’s approved label. As such, we may not promote our products for indications or uses for which they do not have approval. The holder of an approved NDA, BLA, 351(k) application or marketing authorization application, or MAA, must submit new or supplemental applications and obtain approval for certain changes to the approved product, product labeling, or manufacturing process. We could also be asked to conduct post-marketing clinical studies to verify the safety and efficacy of

-44-

Table of Contents

our products in general or in specific patient subsets. An unsuccessful post-marketing study or failure to complete such a study could result in the withdrawal of marketing approval.

If a regulatory agency discovers previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems with the facility where the product is manufactured or disagrees with the promotion, marketing or labeling of a product, or if we or our collaboration partners fail to comply with applicable continuing regulatory requirements, such regulatory agency may impose restrictions on that product or us, including requiring withdrawal of the product from the market. If we or our collaboration partners fail to comply with applicable regulatory requirements, a regulatory agency or enforcement authority may subject us to administrative or judicially imposed sanctions or other actions, including, among other things:

Any government investigation of alleged violations of law could require us to expend significant time and resources in response, and could generate negative publicity. Any failure to comply with ongoing regulatory requirements may significantly and adversely affect our ability to commercialize and generate revenue from our products. If regulatory sanctions are applied or if regulatory approval is withdrawn, the value of our company and our operating results will be adversely affected.

We will also be subject to various health care fraud and abuse laws, including anti-kickback, false claims and fraud laws, and physician payment transparency laws, and any violations by us of such laws could result in fines or other penalties.

Although we currently do not have any products on the market, if our product candidates are approved and we begin commercialization, we will be subject to healthcare regulation and enforcement by the federal government and the states and EEA and other foreign governments in which we conduct our business. These laws include, without limitation, state and federal, as well as EEA and other foreign, anti-kickback, fraud and abuse, false claims, privacy and security and physician sunshine laws and regulations.

The federal anti-kickback statute prohibits the offer, receipt, or payment of remuneration in exchange for or to induce the referral of patients or the use of products or services that would be paid for in whole or part by Medicare, Medicaid or other federal health care programs. Remuneration has been broadly defined to include anything of value, including cash, improper discounts, and free or reduced price items and services. The government has enforced the Anti-Kickback Statute to reach large settlements with healthcare companies based on sham research or consulting and other financial arrangements with physicians. Further, the Affordable Care Act, among other things, amended the intent requirement of the federal Anti-Kickback Statute and certain criminal statutes governing healthcare fraud. A person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it. In addition, the Affordable Care Act provided that the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the FCA or federal civil money penalties statute. Many states have similar laws that apply to their state health care programs as well as private payors. Violations of the

-45-

Table of Contents

anti-kickback laws can result in exclusion from federal health care programs and substantial civil and criminal penalties.

The FCA imposes liability on persons who, among other things, present or cause to be presented false or fraudulent claims for payment by a federal health care program. The FCA has been used to prosecute persons submitting claims for payment that are inaccurate or fraudulent, that are for services not provided as claimed, or for services that are not medically necessary. Actions under the FCA may be brought by the Attorney General or as a qui tam action by a private individual in the name of the government. Violations of the FCA can result in significant monetary penalties and treble damages. The federal government is using the FCA, and the accompanying threat of significant liability, in its investigation and prosecution of pharmaceutical and biotechnology companies throughout the country, for example, in connection with the promotion of products for unapproved uses and other sales and marketing practices. The government has obtained multi-million and multi-billion dollar settlements under the FCA in addition to individual criminal convictions under applicable criminal statutes. In addition, companies have been forced to implement extensive corrective action plans, and have often become subject to consent decrees or corporate integrity agreements, severely restricting the manner in which they conduct their business. Given the significant size of actual and potential settlements, it is expected that the government will continue to devote substantial resources to investigating healthcare providers’ and manufacturers’ compliance with applicable fraud and abuse laws. If our future marketing or other arrangements were determined to violate anti-kickback or related laws, including the FCA, then our revenue could be adversely affected, which would likely harm our business, financial condition, and results of operations.

In addition, there has been a recent trend of increased federal and state regulation of payments made to physicians and other healthcare providers. The Affordable Care Act, among other things, imposed new reporting requirements on drug manufacturers for payments made by them to physicians and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members. Failure to submit required information may result in civil monetary penalties of up to an aggregate of $150,000 per year (or up to an aggregate of $1 million per year for “knowing failures”), for all payments, transfers of value or ownership or investment interests that are not timely, accurately and completely reported in an annual submission. Drug manufacturers must submit reports by the 90th day of each calendar year. Certain states also mandate implementation of commercial compliance programs, impose restrictions on device manufacturer marketing practices and/or require the tracking and reporting of gifts, compensation and other remuneration to physicians.

The shifting commercial compliance environment and the need to build and maintain robust and expandable systems to comply with different compliance and/or reporting requirements in multiple jurisdictions increase the possibility that a healthcare company may violate one or more of the requirements. If our operations are found to be in violation of any of such laws or any other governmental regulations that apply to us, we may be subject to penalties, including, without limitation, civil and criminal penalties, damages, fines, the curtailment or restructuring of our operations, exclusion from participation in federal and state healthcare programs and imprisonment, any of which could adversely affect our ability to operate our business and our financial results.

Also, the U.S. Foreign Corrupt Practices Act and similar worldwide anti-bribery laws generally prohibit companies and their intermediaries from making improper payments to non-U.S. officials for the purpose of obtaining or retaining business. We cannot assure investors that our internal control policies and procedures will protect us from reckless or negligent acts committed by our employees, future distributors, partners, collaborators or agents. Violations of these laws, or allegations of such violations, could result in fines, penalties or prosecution and have a negative impact on our business, results of operations and reputation.

A failure to adequately protect individually identifiable health information could result in severe harm to our reputation and subject us to significant liabilities, each of which could have a material adverse effect on our business.

Throughout the clinical trial process, we may obtain the identifiable health information of our trial subjects. There are a number of state, federal and international laws protecting the privacy and security of health

-46-

Table of Contents

information and personal data, some of which we may be subject to. The Health Insurance Portability and Accountability Act of 1996, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, and their implementing regulations (collectively referred to as HIPAA) imposes limitations on the use and disclosure of individually identifiable health information by healthcare providers conducting certain electronic transactions, healthcare clearinghouses, and health insurance plans, collectively referred to as covered entities. HIPAA also imposes compliance obligations and corresponding penalties for non-compliance on certain individuals and entities that provide services to or perform certain functions on behalf of healthcare providers and other covered entities involving the use or disclosure of individually identifiable health information, collectively referred to as business associates. HIPAA imposes mandatory civil and criminal penalties for violations of its requirements, with mandatory penalties ranging up to $50,000 per violation, with a maximum civil penalty of $1.5 million in a calendar year for violations of the same requirement. However, a single breach incident can result in violations of multiple requirements, resulting in possible penalties well in excess of $1.5 million. HIPAA also authorizes state attorneys general to bring civil actions for violations of HIPAA on behalf of their state’s residents. HIPAA also contains notification requirements to federal regulators, and in some cases local and national media, when covered entities or business associates experience breaches of unsecured protected health information. Notification is not required under HIPAA if the health information that is improperly used or disclosed is deemed secured in accordance with certain encryption or other standards developed by the U.S. Department of Health and Human Services, or HHS. While we are not currently classified as a covered entity or business associate under HIPAA, and thus are not subject to its requirements, we do maintain sensitive identifiable personal information, including health information. As such, we may be subject to state laws requiring notification of affected individuals and state regulators in the event of a breach of personal information, which is a broader class of information than the health information protected by HIPAA. Many state laws impose significant data security requirements, such as encryption or mandatory contractual terms to ensure ongoing protection of personal information. Activities outside of the U.S. implicate local and national data protection standards, impose additional compliance requirements and generate additional risks of enforcement for noncompliance. The EU’s Data Protection Directive and other data protection, privacy and similar national, state/provincial and local laws may also restrict the access, use and disclosure of patient health information abroad. We may be required to expend significant capital and other resources to ensure ongoing compliance with applicable privacy and data security laws, to protect against security breaches and hackers or to alleviate problems caused by such breaches.

Legislative or regulatory healthcare reforms in the United States may make it more difficult and costly for us to obtain regulatory approval of PF582, PF530 or any future product candidates and to produce, market, and distribute our products after approval is obtained, if any.

From time to time, legislation is drafted and introduced in Congress that could significantly change the statutory provisions governing the regulatory approval, manufacturing, and marketing of regulated products or the reimbursement thereof. In addition, FDA regulations and guidance may be revised or reinterpreted by the FDA in ways that may significantly affect our business and our products. Any new regulations or guidance, or revisions or reinterpretations of existing regulations or guidance, may impose additional costs or lengthen FDA review times for PF582, PF530 or any future product candidates. We cannot determine how changes in regulations, statutes, policies, or interpretations when and if issued, enacted or adopted, may affect our business in the future. Such changes could, among other things, require:

Such changes would likely require substantial time and impose significant costs, and could materially harm our business and our financial results. In addition, delays in receipt of or failure to receive regulatory clearances or approvals for any future products would harm our business, financial condition, and results of operations.

-47-

Table of Contents

If efforts by manufacturers of reference products to delay or limit the use of biosimilars are successful, our sales of biosimilar products may suffer.

Many manufacturers of reference products have increasingly used legislative, regulatory and other means in attempts to delay regulatory approval of and competition from biosimilars. These efforts have included sponsoring legislation to prevent pharmacists from substituting biosimilars for prescribed reference products or to make such substitutions more difficult by establishing notification, recordkeeping, and/or other requirements, as well as seeking to prevent manufacturers of biosimilars from referencing the brands of the innovator products in biosimilar product labels and marketing materials. If these or other efforts to delay or block competition are successful, we may be unable to sell our biosimilar product candidates, which could have a material adverse effect on our sales and profitability.

Our and our collaboration partners’ future sales will be dependent on the availability and level of coverage and reimbursement from third-party payors who continue to implement cost-cutting measures and more stringent reimbursement standards.

In the United States and internationally, our and our collaboration partners’ ability to generate revenue on future sales of our products will be dependent, in significant part, on the availability and level of coverage and reimbursement from third-party payors, such as state and federal governments and private insurance plans. Insurers have implemented cost-cutting measures and other initiatives to enforce more stringent reimbursement standards and likely will continue to do so in the future. These measures include the establishment of more restrictive formularies and increases in the out-of-pocket obligations of patients for such products. In addition, particularly in the U.S. and increasingly in other countries, we will be required to provide discounts and pay rebates to state and federal governments and agencies in connection with purchases of our products that are reimbursed by such entities.

In addition, in the United States, the full impact of recent healthcare reform and other changes in the healthcare industry and in healthcare spending is currently unknown. In March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, collectively referred to as the Affordable Care Act, was enacted with a goal of reducing the cost of healthcare and substantially changing the way healthcare is financed by both government and private insurers. The Affordable Care Act, among other things, subjected biologic products to potential competition by lower-cost biosimilars, addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected, increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees and taxes on manufacturers of certain prescription drugs, and created a new Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 50% point-of-sale discounts off negotiated prices of applicable reference product drugs to eligible beneficiaries during their coverage gap period as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D.

Other legislative changes have been proposed and adopted in the U.S. since the Affordable Care Act was enacted. On August 2, 2011, the Budget Control Act of 2011 created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This included aggregate reductions of Medicare payments to providers of 2% per fiscal year, which went into effect on April 1, 2013 and will stay in effect through 2024 unless additional Congressional action is taken. On January 2, 2013, the American Tax Payer Relief Act, or ATRA, was signed into law, which, among other things, further reduced Medicare payments to several providers, including hospitals.

We expect that additional healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal, state and foreign governments will pay for healthcare products and services, which could result in reduced demand for our products, if approved, or additional pricing pressures.

-48-

Table of Contents

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

In some foreign countries, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. Our existing or future collaboration partners, if any, may elect to reduce the price of our products in order to increase the likelihood of obtaining reimbursement approvals which could adversely affect our revenues and profits. To obtain reimbursement or pricing approval in some countries, we or our collaboration partners may also be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be adversely affected.

Risks Relating to This Offering and Ownership of Our Common Stock

New investors in our common stock will experience immediate and substantial dilution after this offering.

If you purchase shares of our common stock in this offering, you will experience substantial and immediate dilution of $         per share in the as adjusted net tangible book value per share of our common stock as of December 31, 2014, based on the difference between an assumed public offering price of $         per share, which was the last reported sales price of our common stock on NYSE MKT on                     , 2015, and the as adjusted net tangible book value per share of our common stock as of December 31, 2014, because the price that you pay will be substantially greater than our net tangible book value per share of the common stock that you acquire. This dilution is due in large part to the fact that our earlier investors paid substantially less than the public offering price when they purchased their shares of our capital stock. You will experience additional dilution upon exercise of options to purchase common stock under our equity incentive plans, if we issue restricted stock to our employees under our equity incentive plan, or if we otherwise issue additional shares of our common stock. For a further description of the dilution that you will experience immediately after this offering, see “Dilution.”

We expect that the market price of our stock will fluctuate significantly, and investors may have difficulty selling their shares.

Our stock is currently traded on NYSE MKT, but we can provide no assurance that we will be able to maintain an active trading market on NYSE MKT or any other exchange in the future. The trading volume of our stock tends to be low relative to our total outstanding shares, and we have several stockholders, including affiliated stockholders, who hold substantial blocks of our stock. As of December 31, 2014, we had 20,405,066 shares of common stock outstanding, and stockholders holding at least 5% of our stock, individually or with affiliated persons or entities, collectively beneficially owned or controlled approximately 59% of such shares before this offering, and approximately     % of such shares following this offering, assuming no exercise of the underwriters’ option to purchase additional shares. Sales of large numbers of shares by any of our large stockholders could adversely affect our trading price, particularly given our relatively small historic trading volumes. If stockholders holding shares of our common stock sell, indicate an intention to sell, or if it is perceived that they will sell, substantial amounts of their common stock in the public market, the trading price of our common stock could decline.

Since shares of our common stock were sold in our initial public offering in July 2014 at a price of $6.00 per share, our stock price has ranged from $5.28 to $19.95 through April 14, 2015. In addition to the factors discussed in this “Risk Factors” section and elsewhere in this prospectus, factors that may cause volatility in our share price include:

-49-

Table of Contents

The stock market in general and market prices for the securities of biopharmaceutical companies like ours in particular, have from time to time experienced volatility that often has been unrelated to the operating performance of the underlying companies. A certain degree of stock price volatility may also occur as a result of being a newly public company. These broad market and industry fluctuations may adversely affect the market price of our common stock, regardless of our operating performance.

We may be subject to securities litigation, which is expensive and could divert management attention.

The market price of our common stock has been and will likely to continue to be volatile, and in the past companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation. We may be the target of this type of litigation in the future. Securities litigation against us could result in substantial costs and divert our management’s attention from other business concerns, which could seriously harm our business.

If securities or industry analysts publish unfavorable research about our business or cease to cover our business, our stock price and/or trading volume could decline.

The trading market for our common stock may rely, in part, on the research and reports that equity research analysts publish about us and our business. We do not have any control of the analysts or the content and opinions included in their reports. The price of our stock could decline if one or more equity research analysts downgrade our stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of our company or fails to publish reports on us regularly, demand for our stock could decrease, which in turn could cause our stock price or trading volume to decline.

If we sell shares of our common stock in future financings, stockholders may experience immediate dilution and, as a result, the market price of our common stock may decline.

We may from time to time issue additional shares of common stock at a discount from the current trading price of our common stock. As a result, our stockholders would experience immediate dilution upon the purchase of any shares of our common stock sold at such discount. In addition, as opportunities present themselves, we may enter into financing or similar arrangements in the future, including the issuance of debt securities, preferred stock or common stock. If we issue common stock or securities convertible into common stock, our common stockholders would experience additional dilution and, as a result, the market price of our common stock may decline.

Sales of substantial amounts of our common stock in the public markets, or the perception that such sales might occur, could reduce the price that our common stock might otherwise attain and may dilute your voting power and your ownership interest in us.

Sales of a substantial number of shares of our common stock in the public market after this offering, or the perception that such sales could occur, could adversely affect the market price of our common stock and may

-50-

Table of Contents

make it more difficult for you to sell your common stock at a time and price that you deem appropriate. Based on the total number of outstanding shares of our common stock as of December 31, 2014, upon completion of this offering, we will have              shares of common stock outstanding, assuming no exercise of our outstanding options after December 31, 2014.

The lock-up agreements pertaining to this offering will expire 90 days from the date of this prospectus for our executive officers, directors, and selling stockholders, following which                          shares of common stock will be freely tradable in the public market without restriction or further registration under the Securities Act, unless these shares are held by “affiliates,” as that term is defined in Rule 144 under the Securities Act. Upon completion of this offering, all 9,429,084 shares of common stock sold in our initial public offering (inclusive of 1,095,751 shares of common stock from the exercise of the underwriters’ option to purchase additional shares) and all of the shares of common stock sold in this offering by us and our selling stockholders and any shares sold upon the exercise of the underwriters’ option to purchase additional shares will be freely tradable in the public market without restriction or further registration under the Securities Act, unless these shares are held by “affiliates,” as that term is defined in Rule 144 under the Securities Act.

In addition, following the completion of this offering, holders of up to approximately              million shares of our common stock, or approximately     % of our total outstanding common stock, will be entitled to rights with respect to registration of these shares under the Securities Act pursuant to an investors’ rights agreement. If these holders of our common stock, by exercising their registration rights, sell a large number of shares, they could adversely affect the market price for our common stock. If we file a registration statement for the purpose of selling additional shares of common stock to raise capital and are required to include shares held by these holders pursuant to the exercise of their registration rights, our ability to raise capital may be impaired.

Furthermore, certain our executive officers have adopted, and other directors and executive officers may in the future adopt, written plans, known as “Rule 10b5-1 Plans,” under which they have contracted, or may in the future contract, with a broker to sell shares of our common stock on a periodic basis to diversify their assets and investments. Sales of substantial amounts of our common stock in the public markets following the release of the lock-up agreements or otherwise, including, but not limited to, sales made by our executive officers and directors pursuant to Rule 10b5-1 Plans, or the perception that these sales could occur, could cause the market price of our common stock to decline.

We are an “emerging growth company,” and the reduced disclosure requirements applicable to emerging growth companies could make our common stock less attractive to investors.

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups, or JOBS, Act enacted in April 2012, and may remain an “emerging growth company” for up to five years following the completion of our initial public offering, although, if we have more than $1.0 billion in annual revenue, if the market value of our common stock that is held by non-affiliates exceeds $700 million as of December 31 of any year, or we issue more than $1.0 billion of non-convertible debt over a three-year period before the end of that five-year period, we would cease to be an “emerging growth company” as of the following December 31. For as long as we remain an “emerging growth company,” we are permitted and intend to rely on exemptions from certain disclosure requirements that are applicable to other public companies that are not “emerging growth companies.” These exemptions include:

-51-

Table of Contents

We have taken advantage of reduced reporting burdens in our reports filed with the SEC. In addition, the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards, delaying the adoption of these accounting standards until they would apply to private companies. We have elected to avail ourselves of this exemption and, as a result, our financial statements may not be comparable to the financial statements of reporting companies who are required to comply with the effective dates for new or revised accounting standards that are applicable to public companies. We cannot predict whether investors will find our common stock less attractive as a result of our reliance on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and the market price of our common stock may be reduced or more volatile.

If we fail to maintain effective internal control over financial reporting in the future, the accuracy and timing of our financial reporting may be adversely affected.

In connection with the audit of our financial statements for the year ended December 31, 2013, we concluded that there were material weaknesses in our internal control over financial reporting. A material weakness is a significant deficiency, or a combination of significant deficiencies, in internal control over financial reporting such that it is reasonably possible that a material misstatement of the annual or interim financial statements will not be prevented or detected on a timely basis. The material weaknesses that we identified related to (1) a lack of sufficient staff to deal with the various rules and regulations with respect to financial reporting, review and oversight responsibilities, segregation of duties and effective and timely financial close process; and (2) a lack of formalized and documented policies and procedures.

In response to these reported material weaknesses, we undertook the following steps in 2014 to remediate those weaknesses: (1) hired outside consultants with technical skills to assist in the documentation and implementation of internal controls and flows procedures, (2) hired qualified personnel, including a chief financial officer during the second quarter of 2014, (3) hired additional qualified finance staff for certain key positions in the third and fourth quarters of 2014 in order to enhance oversight, review and control over financial reporting, and (4) established formalized and documented policies and procedures in the fourth quarter of 2014.

No material weaknesses in internal control over financial reporting were identified in connection with our 2014 audit. However, our management and independent registered public accounting firm did not perform an evaluation of our internal control over financial reporting during any period in accordance with the provisions of the Sarbanes-Oxley Act. Had we and our independent registered public accounting firm performed an evaluation of our internal control over financial reporting in accordance with the provisions of the Sarbanes-Oxley Act, additional control deficiencies amounting to significant deficiencies or material weaknesses may have been identified. We cannot be certain as to when we will be able to implement the requirements of Section 404 of the Sarbanes-Oxley Act. If we fail to implement the requirements of Section 404 in a timely manner, we might be subject to sanctions or investigation by regulatory agencies such as the SEC. In addition, failure to comply with Section 404 or the report by us of a significant deficiency or material weakness may cause investors to lose confidence in our financial statements, and the trading price of our common stock may decline. If we fail to remedy any significant deficiency or material weakness, our financial statements may be inaccurate, our access to the capital markets may be restricted and the trading price of our ordinary shares may suffer.

Our ability to use net operating losses and tax credit carryforwards to offset future taxable income may be subject to certain limitations.

As of December 31, 2014, we had federal net operating loss carry forwards, or NOLs, of approximately $14.2 million, which can be carried forward until 2032 and state NOLs of $15.8 million which can be carried forward until 2029 unless utilized. As of December 31, 2014, we had federal and state research and development carryforwards of approximately $0.5 million and $0.3 million, respectively. Pursuant to Internal Revenue Code (IRC) Sections 382 and 383, annual use of the Company’s net operating loss and research and development

-52-

Table of Contents

credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has undertaken, but has not completed, an IRC Section 382/383 analysis regarding the limitation of net operating loss and research and development credit carryforwards.

We will incur 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 and corporate governance practices including maintaining an effective system of internal control over financial reporting.

As a public company, and increasingly after we are no longer an “emerging growth 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 and rules subsequently implemented by the Securities and Exchange Commission, or SEC, and the NYSE MKT impose numerous requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Also, the Securities Exchange Act of 1934, as amended, or the Exchange Act, requires, among other things, that we file annual, quarterly and current reports with respect to our business and operating results. Our management and other personnel will need to devote a substantial amount of time to comply with these laws and regulations. These requirements have increased and will continue to increase our legal, accounting, and financial compliance costs and have made and will continue to 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. These rules and regulations could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors or our board committees or as executive officers.

Overall, we estimate that our incremental costs resulting from operating as a public company, including compliance with these rules and regulations, may be between $2.0 million and $4.0 million per year. However, these rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and changing governance practices.

The Sarbanes-Oxley Act requires, among other things, that we assess the effectiveness of our internal control over financial reporting annually and the effectiveness of our disclosure controls and procedures quarterly. In particular, Section 404(a) of the Sarbanes-Oxley Act will require us to perform system and process evaluation and testing of our internal control over financial reporting to allow management to report on the effectiveness of our internal control over financial reporting. Section 404(b) of Sarbanes-Oxley Act, or Section 404(b), also requires our independent registered public accounting firm to attest to the effectiveness of our internal control over financial reporting. As an “emerging growth company” we expect to avail ourselves of the exemption from the requirement that our independent registered public accounting firm attest to the effectiveness of our internal control over financial reporting under Section 404(b). However, we may no longer avail ourselves of this exemption when we are no longer an “emerging growth company.” When our independent registered public accounting firm is required to undertake an assessment of our internal control over financial reporting, the cost of our compliance with Section 404(b) will correspondingly increase. Our compliance with applicable provisions of Section 404 will require that we incur substantial accounting expense and expend significant management time on compliance-related issues as we implement additional corporate governance practices and comply with reporting requirements.

Furthermore, investor perceptions of our company may suffer if deficiencies are found, and this could cause a decline in the market price of our stock. Irrespective of any required compliance with Section 404, any failure of our internal control over financial reporting could have a material adverse effect on our stated operating results and harm our reputation. If we are unable to implement these requirements effectively or efficiently, it could harm our operations, financial reporting, or financial results and could result in an adverse opinion on our internal controls from our independent registered public accounting firm.

-53-

Table of Contents

Our directors, executive officers and principal stockholders will continue to have substantial control over us and could limit investors’ ability to influence the outcome of key transactions, including transactions that would cause a change of control.

As of December 31, 2014, our executive officers, directors and stockholders who owned more than 5% of our outstanding common stock and their respective affiliates beneficially owned or controlled approximately 63% of the outstanding shares of our common stock. Accordingly, these executive officers, directors and stockholders and their respective affiliates, acting as a group, have substantial influence over the outcome of corporate actions requiring stockholder approval, including the election of directors, any merger, consolidation or sale of all or substantially all of our assets or any other significant corporate transactions. These stockholders may therefore delay or prevent a change of control of us, even if such a change of control would benefit our other stockholders. The significant concentration of stock ownership may adversely affect the trading price of our common stock due to investors’ perception that conflicts of interest may exist or arise.

Claims for indemnification by our directors and officers may reduce our available funds to satisfy successful third party claims against us and may reduce the amount of money available to us.

Our amended and restated certificate of incorporation and amended and restated bylaws provide that we will indemnify our directors and officers, in each case to the fullest extent permitted by Delaware law.

In addition, as permitted by Section 145 of the Delaware General Corporation Law, our amended and restated bylaws and our indemnification agreements that we have entered into with our directors and officers provide that:

To the extent that a claim for indemnification is brought by any of our directors or officers, it would reduce the amount of funds available for use in our business.

-54-

Table of Contents

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

Provisions in our certificate of incorporation and bylaws may have the effect of delaying or preventing a change of control or changes in our management. Our amended and restated certificate of incorporation and amended and restated bylaws include provisions that:

These provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, which is responsible for appointing the members of our management. In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which limits the ability of stockholders owning in excess of 15% of our outstanding voting stock to merge or combine with us.

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

We will receive net proceeds of approximately $         million from this offering, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. We have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our common stock. Our management will have broad discretion in the application of the net proceeds to us from this offering, including for any of the purposes described in the section entitled “Use of Proceeds,” and you will not have the opportunity as part of your investment decision to assess whether the net proceeds are being used appropriately. Stockholders will not have the opportunity to influence our management’s decisions on how to use the net proceeds, and our failure to apply these funds effectively could have a material adverse effect on our business and cause the price of our common stock to decline. In addition, until the net proceeds are used, they may be placed in investments that do not produce significant income or that may lose value.

-55-

Table of Contents

With the exception of the issuance of shares of common stock to our preferred stockholders in connection with the payment of all accrued and unpaid dividends in connection with our initial public offering, we do not anticipate paying any cash dividends in the foreseeable future.

At the closing of our initial public offering, our board of directors issued shares of common stock to pay all accrued but unpaid dividends on our convertible preferred stock. As of July 29, 2014, there were cumulative unpaid dividends of $7.3 million for our Series A-1 and Series A-2 convertible preferred stock. Based on the initial public offering price of $6.00 per share and the offering closing on July 29, 2014, we issued 1,217,784 shares of common stock to the holders of our outstanding preferred stock prior to the offering in satisfaction of these accrued dividends through July 28, 2014. With the exception of this dividend, we do not anticipate paying cash dividends on any classes of our capital stock in the foreseeable future. We currently intend to retain our future earnings for the foreseeable future to fund the development and growth of our business. As a result, capital appreciation, if any, of our common stock will be the sole source of gain on an investment in our common stock for the foreseeable future.

-56-

Table of Contents