10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended March 31, 2007

OR

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                  to

Commission file number: 0-14656

REPLIGEN CORPORATION

(Exact name of Registrant as specified in its charter)

Delaware	04-2729386
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

41 Seyon Street, Building #1, Suite 100, Waltham, Massachusetts	02453
(Address of Principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (781) 250-0111

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class

Common Stock, $0.01 Par Value Per Share

Series A Junior Participating Preferred Stock Purchase Rights

Name of Each Exchange on Which Registered

The NASDAQ Stock Market LLC

Securities registered pursuant to Section 12(g) of the Act: None

Title of Each Class

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  þ.

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  þ.

Indicate by checkmark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  þ    No  ¨.

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer  ¨            Accelerated filer  þ            Non-accelerated filer   ¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No   þ.

The aggregate market value of the voting and non-voting common equity held by non-affiliates as of September 30, 2006 the last business day of the registrant’s most recently completed second fiscal quarter, was approximately $103,345,159.

The number of shares of outstanding of the registrant’s common stock as of June 6, 2007 was 30,477,635.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Company’s definitive Proxy Statement in connection with the 2007 annual meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.

Table of Contents

		PAGE
PART I
Item 1.	Business	3
Item 1A.	Risk Factors	11
Item 1B.	Unresolved Staff Comments	17
Item 2.	Properties	17
Item 3.	Legal Proceedings	17
Item 4.	Submission of Matters to a Vote of Security Holders	18
PART II
Item 5.	Market for the Registrant’s Common Stock and Related Security Holder Matters	19
Item 6.	Selected Consolidated Financial Data	20
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	21
Item 7A.	Quantitative and Qualitative Disclosures About Market Risk	32
Item 8.	Financial Statements and Supplementary Data	32
Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	32
Item 9A.	Controls and Procedures	32
Item 9B	Other Information	35
Part III		36
PART IV
Item 15.	Exhibits and Financial Statement Schedules	37
SIGNATURES		41

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PART I

Item 1. BUSINESS.

The following discussion of our business contains forward-looking statements that involve risks and uncertainties. When used in this report, the words “intend,” “anticipate,” “believe,” “estimate,” “plan” and “expect” and similar expressions as they relate to us are included to identify forward-looking statements. Our actual results could differ materially from those anticipated in these forward-looking statements and are a result of certain factors, including those set forth under “Risk Factors” and elsewhere in this Annual Report on Form 10-K.

Repligen Corporation (“Repligen,” the “Company” or “we”) is developing novel therapeutics for the treatment of diseases of the central nervous system. We also own intellectual property on two biological therapies which may provide future revenues to support our product development efforts in neurological diseases. We also are a leading manufacturer of Protein A which is used in the production of many therapeutic monoclonal antibodies.

Our business strategy is to maintain full commercial rights to our product candidates through “proof of principle” clinical studies after which we may seek corporate partners for further development and marketing. We partially fund the development of our proprietary therapeutic product candidates with the profits derived from the sales of our commercial products. This will enable us to independently advance our product with less financial risk.

We were incorporated in May 1981, under the laws of the State of Delaware. Our principle executive offices are at 41 Seyon Street, Waltham, Massachusetts 02453 and our telephone number is (781) 250-0111.

Currently Marketed Products

We currently sell two products: Protein A, which is used in the production of monoclonal antibodies, and SecreFlo^®, a synthetic form of the hormone secretin, which is used as an aid in the diagnosis of certain diseases of the pancreas.

Protein A Products for Antibody Manufacturing

Protein A is widely used in the purification of therapeutic monoclonal antibodies. Most therapeutic monoclonal antibodies are manufactured by the fermentation of mammalian cells that express the monoclonal antibody. The monoclonal antibody is typically produced by a process in which an impure fermentation broth containing the desired monoclonal antibody is passed over a solid support to which Protein A has been chemically attached or “immobilized”. The immobilized Protein A binds the monoclonal antibody while other impurities are washed away. The monoclonal antibody is then recovered from the support in a substantially purified form.

We manufacture and market several products based on recombinant forms of Protein A. Our primary customers incorporate our Protein A products into their proprietary monoclonal antibody purification systems that they sell directly to the biotechnology and pharmaceutical industry. In February 2005, we announced an amended and expanded Supply Agreement (“the Agreement”) with GE Healthcare (“GEHC”), the leading supplier of purification products to the biopharmaceutical industry and the largest consumer of Protein A. The Agreement calls for Repligen to be the primary supplier of Protein A to GEHC through 2010. During 2006, we completed the scale up and production of a modified form of Protein A for GEHC, which may provide additional value to the producers of monoclonal antibodies. In addition, we have a long term supply agreement with Applied Biosystems that provides that Repligen will be the preferred provider of recombinant Protein A to Applied Biosystems until 2011. The majority of our product sales for the last three years have been sales of Protein A products.

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Sales of therapeutic monoclonal antibodies have increased from $300 million in 1997 to approximately $20 billion in 2006. This growth is based on the increasing use of therapeutic antibodies, including Erbitux^® for colon cancer, Synagis^® for RSV infection and Remicade^® for Crohn’s disease and arthritis. There are more than 150 additional monoclonal antibodies in various stages of clinical testing which may lead to additional growth of the antibody market and in turn, increased demand for Protein A.

SecreFlo^® for Pancreatic Diagnosis

In October 1999, we licensed exclusive commercial rights to a diagnostic product based on a synthetic form of porcine (pig-derived) secretin, which we market as SecreFlo^®, from ChiRhoClin, Inc. (“ChiRhoClin”), a private company. ChiRhoClin is our sole supplier of SecreFlo^®. SecreFlo^® is approved by the U.S. Food and Drug Administration (“FDA”) as an aid in the diagnosis of chronic pancreatitis and gastrinoma (a form of cancer) and as an aid during endoscopic retrograde cholangiopancreatography (“ERCP”), a gastrointestinal procedure. In 2004, we terminated our agreement with ChiRhoClin for breach and filed an arbitration proceeding against ChiRhoClin for their alleged failure to meet certain obligations related to product and clinical development. In May 2005, we announced the settlement of the arbitration proceeding through an agreement by which we will continue to sell SecreFlo^®. We estimate that sales of SecreFlo^® will continue through March 2009, when our product supply will cease.

Intellectual Property on Monoclonal Antibody and Antibody Fusion Products

Erbitux^®

Erbitux^® is a monoclonal antibody developed by ImClone Systems Incorporated (“Imclone”) which was approved by the FDA in February 2004 for the treatment of certain forms of colon cancer and in March 2006 for the treatment of head and neck cancer. We believe that Erbitux^® is manufactured with a cell line created by a company whose assets were subsequently acquired by Repligen. This cell line contains certain patented genetic technologies (“DNA enhancers”) which increase the productivity of a cell line. This patent is assigned to MIT and exclusively licensed to Repligen. Imclone previously announced that it had manufactured approximately $1 billion of Erbitux^® as of February 2004. Imclone has reported that nearly all of this pre-approval stockpile of Erbitux^® was exhausted by the end of December 2005. In May 2004, Repligen and MIT jointly filed a lawsuit against Imclone in U.S. District Court for Massachusetts alleging that Imclone has infringed our patent rights in its production of Erbitux^®. Our patent expired in May 2004 and we have applied for a 5-year term extension for the patent, or until May 2009.

CTLA4-Ig

CTLA4 is a key regulator of the activity of the immune system. CTLA4 “turns off” the immune system after it has successfully cleared a bacterial or viral infection by blocking the activation of T-cells, the immune cells responsible for initiating an immune response. In the 1990’s our collaborators at the University of Michigan and the U.S. Navy demonstrated in animal models that a fusion protein consisting of fragments of CTLA4 and an antibody (“CTLA4-Ig”) could be used to block organ transplant rejection and to treat certain autoimmune diseases. Additional animal and human studies by many other groups have confirmed that CTLA4-Ig may be useful in treating diseases such as rheumatoid arthritis, multiple sclerosis, lupus, psoriasis and organ transplant rejection. CTLA4-Ig’s mechanism of action is different from the current therapies for autoimmune disease or organ transplant rejection, thus it may provide a treatment for patients who are refractory to existing therapies.

In December 2005, the FDA approved Bristol-Myers Squibb Corporation’s (“Bristol”) application to market CTLA4-Ig, under the brand name Orencia^®, for treatment of rheumatoid arthritis. Bristol started commercial sales of Orencia^® in February 2006.

In January 2006, Repligen and the University of Michigan jointly filed a lawsuit against Bristol in the United States District Court for the Eastern District of Texas for infringement of U.S. Patent No. 6,685,941. The

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patent, entitled “Methods of Treating Autoimmune Disease via CTLA4-Ig,” covers methods of using CTLA4-Ig to treat rheumatoid arthritis, as well as other therapeutic methods. The patent is in force until 2021. Repligen has exclusive rights to this patent from its owners, the University of Michigan and the U.S. Navy.

Development Stage Products for Neuropsychiatric Disorders

Secretin for MRI

Secretin is a well-known hormone produced in the small intestine that regulates the function of the pancreas as part of the process of digestion. We are currently evaluating secretin for improvement of MRI imaging of the pancreas.

Several reports published in the literature support the use of secretin with abdominal MRI imaging to improve visualization of pancreaticobiliary structures and to increase diagnostic sensitivity relative to unenhanced abdominal MRI. MRI technology images stationary water thus the use of secretin during MRI harnesses the natural biologic properties of secretin, which signals the release of water-rich fluids into the ducts of the pancreas. Improvement in the detection and delineation of normal and abnormal structures with MRI is attractive for patient care as it can obviate the need for more risky invasive procedures.

In June 2006, we initiated a Phase 2 clinical trial to evaluate the use of RG1068, synthetic human secretin, as an agent to improve the detection of structural abnormalities of the pancreatic ducts during MRI imaging of the pancreas. This was a multi-center, baseline controlled, single dose study in which 80 patients with a history of pancreatitis receive a secretin-enhanced MRI and an unenhanced MRI of the pancreas.

In May 2007, we announced positive results from this Phase 2 clinical trial to evaluate the use of RG1068, synthetic human secretin, to improve the assessment of pancreatic duct structures by MRI. The study showed an improvement in sensitivity of detection of structural abnormalities of the pancreatic duct of approximately 20% with no loss in specificity, consistent with prior data and expectations. In addition, the study showed highly significant increases in the following three assessments: physician confidence in their ability to identify structural abnormalities, the number of pancreatic duct segments visualized and improvement in the overall quality of the MRI images. Detailed visual assessment of the pancreatic ducts and identification of structural abnormalities is important in the assessment, diagnosis and treatment of diseases such as acute and chronic pancreatitis. We believe these results establish the basis for discussions with the FDA regarding a clinical plan to receive marketing approval for Secretin for MRI imaging of the pancreas.

Uridine for Bipolar Depression

Uridine is a biological compound essential for the synthesis of DNA and RNA, the basic hereditary material found in all cells, and numerous other factors essential for cell metabolism. Uridine is synthesized by the power plant of the human cell known as the mitochondria. The rationale for uridine therapy in CNS disorders is supported by pre-clinical and clinical research. Researchers at McLean Hospital previously demonstrated that uridine is active in a well-validated animal model of depression. Recent reports indicate that certain genes that encode for mitochondrial proteins are significantly down-regulated in the brains of bipolar patients. This new insight suggests that the symptoms of bipolar disorder may be linked to dysregulation of energy metabolism of the brain.

Bipolar disorder, also known as manic depression, is marked by extreme changes in mood, energy and behavior in which a person can alternate between mania (highs) and depression (lows). Bipolar disorder affects more than 2 million adults in the United States. Current drug therapy for bipolar disorder includes the use of lithium and anti-depressants. However, side effects are frequent and troublesome, and patients do not respond fully, leading to frequent recurrences of mania and depression.

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In March 2006, we initiated a Phase 2 clinical trial of RG2417, an oral formulation of uridine, in patients with bipolar depression. This Phase 2 study is a multi-center, dose escalating study in which 80 patients will receive either RG2417 or a placebo for 6 weeks. Patients will be evaluated for the safety and effectiveness of RG2417 on the symptoms of bipolar depression. This study is being conducted under a development agreement with the Stanley Medical Research Institute, under which Repligen will receive approximately $1,200,000 in funding. The Stanley Medical Research Institute is the largest nonprofit provider of funding for research on schizophrenia and bipolar disorder in the United States. We have completed patient enrollment in this study and we anticipate release of top line data later in 2007.

Repligen previously completed a 6-week Phase 1 clinical trial of a prodrug of uridine (RG2133) in patients with bipolar disorder or major depression. The results demonstrated that administration of RG2133 in this patient population appeared to be safe, did not induce mania, and provided early evidence of a clinical effect of the drug. The trial evaluated 19 patients and was carried out by investigators at McLean Hospital, the largest psychiatric clinical care, teaching and research affiliate of Harvard Medical School.

Transcription Enhancers for Friedreich’s Ataxia

Symptoms of Friedreich’s ataxia typically emerge between the ages of 5 and 15 and often progress to severe disability, incapacitation or loss of life in early adulthood. Friedreich’s ataxia is caused by a single gene defect that results in inadequate production of the protein frataxin. The protein frataxin appears to be essential for the proper functioning of the mitochondria, the power plant of both neural and muscle cells. Low levels of frataxin lead to degeneration of both the nerves controlling muscle movements in the arms and legs and the nerve tissue in the spinal cord. Approximately one in every 50,000 people in the United States has Friedreich’s ataxia.

In April 2007, we announced that we entered into an exclusive commercial license with The Scripps Research Institute for intellectual property covering compounds which may have utility in treating Friedreich’s ataxia. Friedreich’s ataxia is an inherited neurodegenerative disease in which low levels of the protein frataxin result in progressive damage to the nervous system and loss of muscle function. Research in tissues derived from patients as well as in mice indicates that the licensed compounds increase production of the protein frataxin, which suggests potential utility of these compounds in slowing or stopping progression of the disease. There is currently no treatment for Friedreich’s ataxia.

Data supporting the ability of the licensed compounds to increase production of the protein frataxin was published in Nature Chemical Biology (August 20, 2006). This research was lead by Dr. Joel Gottesfeld, professor of molecular biology at The Scripps Research Institute, and supported in part by the Friedreich’s Ataxia Research Alliance (FARA). These compounds are the only ones to date that have demonstrated utility in increasing both the level of the frataxin protein in tissue samples from patients with Friedreich’s ataxia as well as frataxin gene activity in animal models. Preliminary data also suggests that these compounds may have utility in treating other disorders such as Spinal Muscular Atrophy and Huntington’s disease.

Repligen’s Business Strategy

Our business strategy is to maintain full commercial rights to our product candidates through “proof of principle” clinical studies after which we may seek corporate partners for further development and marketing. We partially fund the development of our proprietary therapeutic product candidates with the profits derived from the sales of our commercial products. This will enable us to independently advance our product candidates while reducing our financial risks.

Sales and Marketing

We sell our Protein A products primarily through value-added resellers including GEHC and Applied Biosystems, Inc., as well as through distributors in certain foreign markets. We market SecreFlo^® directly to gastroenterologists in the United States.

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Significant Customers and Geographic Reporting

Customers for our Protein A products include chromatography companies, diagnostics companies, biopharmaceutical companies and laboratory researchers. During fiscal years 2007 and 2006, the customers that accounted for more than 10% of our total revenue were GEHC and Applied Biosystems, Inc. During fiscal year 2005, the customers that accounted for more than 10% of our total revenue were GEHC, Applied Biosystems, Inc. and Cardinal Healthcare.

Of our fiscal 2007 product revenue, 47% is attributable to U.S. customers and 53% is attributable to foreign customers, of which 72% is attributable to two customers. Of our fiscal 2006 revenue, 48% is attributable to U.S. customers and 52% is attributable to foreign customers, of which 75% is attributable to two customers. Of our fiscal 2005 revenue, 43% is attributable to U.S. customers and 56% is attributable to foreign customers, of which 77% is attributable to three customers.

Employees

As of June 6, 2007, we had 45 employees. Of those employees, 32 were engaged in research, development and manufacturing and 13 in administrative and marketing functions. Sixteen of our employees hold doctorates or other advanced degrees. Each of our employees has signed a confidentiality agreement. None of our employees are covered by collective bargaining agreements.

Patents, Licenses and Proprietary Rights

Our policy is to seek patent protection for our therapeutic product candidates. We pursue patent protection in the United States and file corresponding patent applications in relevant foreign jurisdictions. We believe that patents are an important element in the protection of our competitive and proprietary position, but other elements, including trade secrets, orphan drug status and know-how, may also be important. We own or have exclusive rights to more than 15 issued U.S. patents and corresponding foreign equivalents. The terms of such patents expire at various times between 2009 and 2021. No patent material to our business expires before 2009. In addition, we have rights to more than 20 U.S. pending patent applications and corresponding foreign applications. The invalidation of key patents owned or licensed by us or the failure of patents to issue on pending patent applications could create increased competition, with potential adverse effects on our business prospects. For each of our license agreements where we license the rights to patents or patent applications, the license will terminate on the day that the last to expire patent covered by each such license agreement expires.

We also rely upon trade secret protection for our confidential and proprietary information. Our policy is to require each of our employees, consultants, business partners and significant scientific collaborators to execute confidentiality agreements upon the commencement of an employment, consulting or business relationship with us. These agreements generally provide that all confidential information developed or made known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees and consultants, the agreements generally provide that all inventions conceived by the individual in the course of rendering services to Repligen shall be our exclusive property.

CTLA4-Ig

We are the exclusive licensee of all CTLA4-Ig patent rights owned by the University of Michigan (“Michigan”). In February 2004, U.S. Patent No. 6,685,941 (“the ‘941 patent”) issued, to which we own the exclusive rights through license agreements with Michigan and the U.S. Navy. The ‘941 patent has claims that cover the use of CTLA4-Ig to treat rheumatoid arthritis, multiple sclerosis and certain other autoimmune disorders and is assigned to the University of Michigan and the U.S. Navy. The ‘941 patent expires in 2021.

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Uridine

In November 2000 and December 2000, Repligen entered into two license agreements (the “UCSD Uridine License Agreements”) with the University of California, San Diego (“UCSD”) for certain patent applications pertaining to the use of uridine and uridine derivatives for the treatment of mitochondrial disease and purine autism. On June 21, 2001, Pro-Neuron, Inc. filed a complaint (the “Pro-Neuron Complaint”) against the Regents of the University of California (the “Regents”) and Repligen in the Superior Court of California, County of San Diego seeking to void the UCSD Uridine License Agreement relating to treatment of mitochondrial disease entered into between Repligen and the UCSD. Pro-Neuron, Inc. subsequently amended the complaint to include the UCSD Uridine License Agreement related to purine autism and claims for misappropriation of trade secrets.

In June 2003, Repligen agreed to restructure the UCSD License Agreements to exclude the field of acylated pyrimidines, including triacetyluridine.

In April 2004, a U.S. patent was issued to Repligen and University of California, which claims methods of treating certain developmental disorders, including certain forms of autism, with uridine compositions which expires in October 2020. Foreign equivalents of this patent are pending. A patent with similar claims has recently issued in Australia.

Protein A

We own a U.S. patent covering recombinant Protein A, which expires in September 2009, as well as significant know-how in the manufacture of high-purity Protein A. We also own a U.S. patent covering modified forms of Protein A, which was non-exclusively licensed to Amersham Biosciences (now GEHC) in 1998 as part of a ten-year agreement, which was amended and extended in 2005 until 2010, covering the supply of Protein A to GEHC.

In addition to its utility in monoclonal antibody manufacturing, Protein A may also be useful in human therapy based on its activity as a B-cell toxin. Repligen has exclusively licensed rights from UCSD to a U.S. patent application which claims a variety of potential therapeutic uses of Protein A. Foreign equivalents of this patent application are also pending.

Research and Development

For the past three years, we have devoted substantial resources to the research and development of therapeutic product candidates and our commercial products and product candidates discussed herein. We spent $5,924,000 in fiscal 2007, $5,163,000 in fiscal 2006, and $5,037,000 in fiscal 2005 on company-sponsored research and development activities.

Competition

Our Protein A and SecreFlo^® products compete on the basis of quality, performance, cost effectiveness, and application suitability with numerous established technologies. Additional products using new technologies that may be competitive with our products may also be introduced. Many of the companies selling or developing competitive products have financial, manufacturing and distribution resources significantly greater than ours.

The field of drug development is characterized by rapid technological change. New developments are expected to continue at a rapid pace in both industry and academia. There are many companies, both public and private, including large pharmaceutical companies, chemical companies and specialized biotechnology companies, engaged in developing products competitive with products that we have under development. Many of these companies have greater capital, human resources, research and development, manufacturing and marketing experience than we do. They may succeed in developing products that are more effective or less costly than any that we may develop. These competitors may also prove to be more successful than we are in production and marketing. In addition, academic, government and industry-based research groups compete intensely with us in

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recruiting qualified research personnel, in submitting patent filings for protection of intellectual property rights and in establishing corporate strategic alliances. We cannot be certain that research, discoveries and commercial developments by others will not render any of our programs or potential products noncompetitive.

Manufacturing

Protein A for Antibody Manufacturing

We manufacture Protein A products from recombinant strains of bacteria. We manufacture Protein A for GEHC under a ten-year supply agreement which was initiated in December 1998. In February 2005, we announced an amended and expanded Supply Agreement with GEHC, the leading supplier of purification products to the biopharmaceutical industry and the largest consumer of Protein A. In addition, we have a long term supply agreement with Applied Biosystems that provides that Repligen will be the preferred provider of recombinant protein A to Applied Biosystems until 2011. We utilize our own facility and third parties to carry out certain fermentation and certain recovery operations, while the purification, immobilization, packaging and quality control testing of Protein A are conducted at our facilities. We maintain an active quality assurance effort to support the regulatory requirements of our customers. We purchase raw materials from more than one commercially established company and believe that the necessary raw materials are currently commercially available in sufficient quantities necessary to meet market demand.

SecreFlo^®

SecreFlo^® our diagnostic secretin product is purchased from ChiRhoClin who contracts with third parties for the synthesis of the drug substance and the drug product. This company is our sole supplier for this product. Under the terms of a settlement agreement, ChiRhoClin is obligated to deliver a certain amount of SecreFlo^® to Repligen. After depletion of all supplies of SecreFlo^® in early 2009, including those to be delivered under the settlement agreement, Repligen will cease marketing and selling SecreFlo^®.

Therapeutic Product Candidates

We currently rely, and will continue to rely, for at least the next few years, upon contract manufacturers for both the procurement of raw materials and the production of our product candidates for use in our clinical trials. Our product candidates will need to be manufactured in a facility by processes that comply with the FDA’s good manufacturing practices and other similar regulations. It may take a substantial period of time to begin manufacturing our products in compliance with such regulations. If we are unable to establish and maintain relationships with third parties for manufacturing sufficient quantities of our product candidates and their components that meet our planned time and cost parameters, the development and timing of our clinical trials may be adversely affected.

We purchase raw materials from more than one commercially established company. Our necessary raw materials are currently commercially available in quantities that far exceed the scale required to complete all of our future planned clinical trials.

Government Regulation

The development of drug candidates is subject to regulation in the United States by the FDA and abroad by foreign equivalents. Product development and approval within the FDA regulatory framework usually takes a significant number of years and involves the expenditure of substantial capital resources. Timelines for development are uncertain.

Before clinical testing in the United States of any drug candidate may begin, FDA requirements for preclinical efficacy and safety must be completed. Required toxicity testing typically involves characterization of the drug candidate in several animal species. Safety and efficacy data are submitted to the FDA as part of an

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Investigational New Drug Application (“IND”) and are reviewed by the FDA prior to the commencement of human clinical trials.

Clinical trials involve the administration of the drug to human volunteers or patients under the supervision of a qualified investigator, usually a physician, with an FDA-approved protocol. Human clinical trials are typically conducted in three sequential phases:

• Phase 1 clinical trials represent the initial administration of the investigational drug to a small group of human subjects to test for safety (adverse effects), dose tolerance, absorption, biodistribution, metabolism, excretion and clinical pharmacology and, if possible, to gain early evidence regarding efficacy.

• Phase 2 clinical trials typically involve a small sample of the actual intended patient population and seek to assess the efficacy of the drug for specific targeted indications, to determine dose tolerance and the optimal dose range, and to gather additional information relating to safety and potential adverse effects.

• Once an investigational drug is found to have some efficacy and an acceptable safety profile in the targeted patient population, Phase 3 clinical trials are initiated to establish further clinical safety and efficacy of the investigational drug in a broader sample of the general patient population at multiple study sites in order to determine the overall risk-benefit ratio of the drug and to provide an adequate basis for product approval. The Phase 3 clinical development program consists of expanded, large-scale studies of patients with the target disease or disorder to obtain definitive statistical evidence of the efficacy and safety of the proposed product.

All data obtained from a comprehensive development program are submitted in a New Drug Application (“NDA”) to the FDA and the corresponding agencies in other countries for review and approval. The NDA includes information pertaining to clinical studies and the manufacture of the new drug. Review of an NDA by the FDA can be a time-consuming process and the FDA may request that we submit additional data or carry out additional studies.

Available Information

We maintain a website with the address www.repligen.com. We are not including the information contained on our website as a part of, or incorporating it by reference into, this annual report on Form 10-K. We make available free of charge through our website our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, and amendments to these reports, as soon as reasonably practicable after we electronically file such materials with, or furnish such materials to, the Securities and Exchange Commission.

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Item 1A. RISK FACTORS

Investors should carefully consider the risk factors described below before making an investment decision.

If any of the events described in the following risk factors occur, our business, financial condition or results of operations could be materially harmed. In that case the trading price of our common stock could decline, and Investors may lose all or part of their investment. Additional risks and uncertainties that we are unaware of or that we currently deem immaterial may also become important factors that affect Repligen.

This annual report on Form 10-K contains forward looking statements that involve risks and uncertainties. Our actual results could differ materially from those anticipated in these forward looking statements as a result of certain factors, including the risks faced by us described below and elsewhere in this annual report on Form 10-K.

We are dependent on others to develop, conduct clinical trials for, manufacture, market and sell our principal products.

We conduct some of our development activities, and conduct most of our commercialization activities, through collaborations. These collaborations include academic researchers as well as contracts with vendors. Our collaborations are heavily dependent on the efforts and activities of our collaborative partners. Our existing and any future collaborations may not be technically or commercially successful. For example, if any of our collaborative partners were to breach or terminate an agreement with us, reduce its funding or otherwise fail to conduct the collaboration successfully, we may need to devote additional internal resources to the program that is the subject of the collaboration, scale back or terminate the program or seek an alternative partner, any of which could lead to delays in development and/or commercialization of our products.

If our clinical trials are not successful, we will not be able to develop and commercialize any related products.

In order to obtain regulatory approvals for the commercial sale of our future products, we and our collaborative partners will be required to complete extensive clinical trials in humans to demonstrate the safety and efficacy of the products. We have limited experience in conducting clinical trials.

The submission of an Investigational New Drug (IND) may not result in FDA authorization to commence clinical trials. If clinical trials begin, we or our collaborative partners may not complete testing successfully within any specific time period, if at all, with respect to any of our products. Furthermore, we, our collaborative partners, or the FDA, may suspend clinical trials at any time on various grounds, including a finding that the subjects or patients are being exposed to unacceptable health risks. Clinical trials, if completed, may not show any potential product to be safe or effective. Thus, the FDA and other regulatory authorities may not approve any of our potential products for any indication.

The rate of completion of clinical trials is dependent in part upon the rate of enrollment of patients. Patient enrollment is a function of many factors, including the size of the patient population, the proximity of patients to clinical sites, the eligibility criteria for the study, and the existence of competitive clinical trials. Delays in planned patient enrollment may result in increased costs and delays in completion of clinical trials.

We may not obtain regulatory approvals; the approval process is costly and lengthy.

We must obtain regulatory approval for our ongoing development activities and before marketing or selling any of our future products. We may not receive regulatory approvals to conduct clinical trials of our products or to manufacture or market our products. In addition, regulatory agencies may not grant such approvals on a timely basis or may revoke previously granted approvals.

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The process of obtaining FDA and other required regulatory approvals is lengthy and expensive. The time required for FDA and other clearances or approvals is uncertain and typically takes a number of years, depending on the complexity and novelty of the product. Our analysis of data obtained from preclinical and clinical activities is subject to confirmation and interpretation by regulatory authorities, which could delay, limit or prevent regulatory approval. Any delay in obtaining or failure to obtain required clearance or approvals could materially adversely affect our ability to generate revenues from the affected product. We have only limited experience in filing and prosecuting applications necessary to gain regulatory approvals.

We are also subject to numerous foreign regulatory requirements governing the design and conduct of the clinical trials and the manufacturing and marketing of our future products. The approval procedure varies among countries. The time required to obtain foreign approvals often differs from that required to obtain FDA approvals. Moreover, approval by the FDA does not ensure approval by regulatory authorities in other countries (or vice versa).

All of the foregoing regulatory risks also are applicable to development, manufacturing and marketing undertaken by our collaborative partners or other third parties.

Even if we obtain marketing approval, our products will be subject to ongoing regulatory review which will be expensive and may affect our ability to successfully commercialize our products.

Even if we or our collaborative partners receive regulatory approval of a product, such approval may be subject to limitations on the indicated uses for which the product may be marketed, which may limit the size of the market for the product or contain requirements for costly post-marketing follow-up studies. The manufacturers of our products for which we or our collaborative partners have obtained marketing approval will be subject to continued review and periodic inspections by the FDA and other regulatory authorities. The subsequent discovery of previously unknown problems with the product, clinical trial subjects, or with a manufacturer or facility may result in restrictions on the product or manufacturer, including withdrawal of the product from the market.

If we or our collaborative partners fail to comply with applicable regulatory requirements, we may be subject to fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions, and criminal prosecution.

If we are unable to obtain, maintain and enforce patents for our products, we will not be able to succeed commercially.

We must obtain and maintain patent and trade secret protection for those of our products and processes for which patent protection is available in order to protect them from unauthorized use and to produce a financial return consistent with the significant time and expense required to bring our products to market. Our success will depend, in part, on our ability to:

• obtain and maintain patent protection for our products and manufacturing processes;

• preserve our trade secrets;

• operate without infringing the proprietary rights of third parties; and

• secure licenses from others on acceptable terms.

We cannot be sure that any patent applications relating to our products that we will file in the future or that any currently pending applications will issue on a timely basis, if ever. Since patent applications in the United States filed prior to November 2000 are maintained in secrecy until patents issue and since publication of discoveries in the scientific or patent literature often lag behind actual discoveries, we cannot be certain that we were the first to make the inventions covered by each of our pending patent applications or that we were the first

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to file patent applications for such inventions. Even if patents are issued, the degree of protection afforded by such patents will depend upon the:

• scope of the patent claims;

• validity and enforceability of the claims obtained in such patents; and

• our willingness and financial ability to enforce and/or defend them.

The patent position of biotechnology and pharmaceutical firms is often highly uncertain and usually involves complex legal and scientific questions. Moreover, no consistent policy has emerged in the United States and in many other countries regarding the breadth of claims allowed in biotechnology patents. Patents which may be granted to us in certain foreign countries may be subject to opposition proceedings brought by third parties or result in suits by us, which may be costly and result in adverse consequences for us.

In some cases, litigation or other proceedings may be necessary to assert claims of infringement, to enforce patents issued to us or our licensors, to protect trade secrets, know-how or other intellectual property rights we own or to determine the scope and validity of the proprietary rights of third parties. Such litigation could result in substantial cost to us and diversion of our resources. An adverse outcome in any such litigation or proceeding could have a material adverse effect on our business, financial condition and results of operations.

If our competitors prepare and file patent applications in the United States that claim technology also claimed by us, we may be required to participate in interference proceedings declared by the U.S. Patent and Trademark Office to determine priority of invention, which would result in substantial costs to us.

We are currently and may in the future be involved in expensive patent litigation or other intellectual property proceedings which could result in liability for damages or stop our development and commercialization efforts.

There has been substantial litigation and other proceedings regarding the complex patent and other intellectual property rights in the pharmaceutical and biotechnology industries. We are a party to, and in the future may become a party to, patent litigation or other proceedings regarding intellectual property rights.

Other types of situations in which we may become involved in patent litigation or other intellectual property proceedings include:

• We may initiate litigation or other proceedings against third parties to seek to invalidate the patents held by such third parties or to obtain a judgment that our products or services do not infringe such third parties’ patents.

• We may initiate litigation or other proceedings against third parties to seek to enforce our patents against infringement.

• If our competitors file patent applications that claim technology also claimed by us, we may participate in interference or opposition proceedings to determine the priority of invention.

• If third parties initiate litigation claiming that our processes or products infringe their patent or other intellectual property rights, we will need to defend against such claims.

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 cost of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. If a patent litigation or other intellectual property proceeding is resolved unfavorably to us, we or our collaborative partners may be enjoined from manufacturing or selling our products and services without a license from the other party and be held liable for significant damages. We may not be able to obtain any required license on commercially acceptable terms or at all.

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Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace. Patent litigation and other proceedings may also absorb significant management time, attention and resources.

For more information about the legal proceeding in which we are involved, please see “Legal Proceedings.”

We may become involved in litigation or other proceedings with collaborative partners, which may be time consuming, costly and could result in delays in our development and commercialization efforts.

We conduct some of our development activities, and conduct most of our commercialization activities, through collaborations with collaborative partners. Therefore, any disputes with such partners that lead to litigation or similar proceedings may result in us incurring legal expenses, as well as facing potential legal liability. Such disputes, litigation or other proceedings are also time consuming and may cause delays in our development and commercialization efforts.

We have limited sales and marketing experience and capabilities.

We have limited sales, marketing and distribution experience and capabilities. We may, in some instances, rely significantly on sales, marketing and distribution arrangements with our collaborative partners and other third parties. In these instances, our future revenues will be materially dependent upon the success of the efforts of these third parties.

If in the future we determine to perform sales, marketing and distribution functions ourselves, we would face a number of additional risks, including:

• we may not be able to attract and build a significant marketing staff or sales force;

• the cost of establishing a marketing staff or sales force may not be justifiable in light of any product revenues; and

• our direct sales and marketing efforts may not be successful.

We have limited manufacturing capabilities and will be dependent on third party manufacturers.

We have limited manufacturing experience and no commercial or pilot scale manufacturing facilities for the production of pharmaceuticals. In order to continue to develop pharmaceutical products, apply for regulatory approvals and, ultimately, commercialize any products, we may need to develop, contract for, or otherwise arrange for the necessary manufacturing capabilities.

We currently rely upon third parties to produce material for preclinical and clinical testing purposes and expect to continue to do so in the future. We also expect to rely upon third parties, including our collaborative partners, to produce materials required for the commercial production of certain of our products if we succeed in obtaining necessary regulatory approvals. We believe that there is no proprietary aspect to the manufacture of our products. However, there are only a limited number of manufacturers that operate under the FDA’s regulations for good manufacturing practices which are capable of and/or approved to manufacture our products. Timing for the initiation of new manufacturers is uncertain, and, if we are unable to arrange for third party manufacturing of our products on a timely basis, or to do so on commercially reasonable terms, we may not be able to complete development of our products or market them. We currently rely upon third parties for fermentation relating to our Protein A products.

We believe that there is no proprietary aspect to the manufacture of our commercial products. However, timing for the initiation of new manufacturers is uncertain, and, if we are unable to arrange for third party manufacturing of our products on a timely basis, or to do so on commercially reasonable terms, we may not be

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able to complete development of our products or market them. To the extent that we enter into manufacturing arrangements with third parties, we are dependent upon these third parties to perform their obligations in a timely manner. If such third party suppliers fail to perform their obligations, we may be adversely affected in a number of ways, including:

• we may not be able to meet commercial demands for our products;

• we may not be able to initiate or continue clinical trials of products that are under development;

• we may be delayed in completing our clinical trials of products under development; and

• we may be delayed in submitting applications for regulatory approvals for our products.

The manufacture of products by us and our collaborative partners and suppliers is subject to regulation by the FDA and comparable agencies in foreign countries. Delay in complying or failure to comply with such manufacturing requirements could materially adversely affect the marketing of our products.

We rely on a single supplier (ChiRhoClin) for our SecreFlo^® product

We rely on a single supplier (ChiRhoClin) for our SecreFlo^® product. Under the terms of our settlement agreement, ChiRhoClin is obligated to deliver a certain amount of SecreFlo^® to Repligen over the next few years The last shipment of SecreFlo^® to the Company from ChiRhoClin should be in late calendar year 2007 and is expected to allow us to fill sales orders into fiscal year 2009. After depletion of all supplies of SecreFlo^®, including those to be delivered under the settlement agreement, Repligen will cease marketing and selling SecreFlo^®. In the event that we are unable to acquire additional products, our revenues may be negatively impacted.

If we are unable to continue to hire and retain skilled personnel, then we will have trouble developing and marketing our products.

Our success depends largely upon the continued service of our management and scientific staff and our ability to attract, retain and motivate highly skilled technical, scientific, management, regulatory compliance and marketing personnel. Potential employees with an expertise in the field of molecular biology, biochemistry, regulatory affairs and/or clinical development of new drug and biopharmaceutical manufacturing are not generally available in the market and are difficult to attract and retain. We also face significant competition for such personnel from other companies, research and academic institutions, government and other organizations who have superior funding and resources to be able to attract such personnel. The loss of key personnel or our inability to hire and retain personnel who have technical, scientific or regulatory compliance backgrounds could materially adversely affect our product development efforts and our business.

The market may not be receptive to our products upon their introduction.

The commercial success of our products that are approved for marketing will depend upon their acceptance by the medical community and third party payors as being clinically useful, cost effective and safe. All of the products that we are developing are based upon new technologies or therapeutic approaches. As a result, it is hard to predict market acceptance of our products.

Other factors that we believe will materially affect market acceptance of our products and services include:

• the timing of receipt of marketing approvals and the countries in which such approvals are obtained;

• the safety, efficacy and ease of administration of our products;

• the success of physician education programs;

• the availability of government and third party payor reimbursement of our products; and

• competition from products which may offer better safety, efficacy or lower cost.

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We compete with pharmaceutical and biotechnology companies who are capable of developing new approaches that could make our products and technology obsolete.

The market for therapeutic and commercial products is intensely competitive, rapidly evolving and subject to rapid technological change. Pharmaceutical and biotechnology companies may have substantially greater financial, manufacturing, marketing, and research and development resources than we have. New approaches by these competitors may make our products and technologies obsolete or noncompetitive.

We have incurred substantial losses, we expect to continue to incur operating losses and we will not be successful until we reverse this trend.

We have incurred operating losses in each year since our founding in 1981. We expect to continue to incur operating losses for the foreseeable future.

While we generate revenue from product sales, this revenue is not sufficient to cover the costs of our clinical trials and drug development programs. We plan to continue to invest in key research and development activities. As a result, we will need to generate significant revenues in order to achieve profitability. We cannot be certain whether or when this will occur because of the significant uncertainties that affect our business.

If we do not obtain additional capital for our drug development programs, we will be unable to develop or discover new drugs.

We need additional long-term financing to develop our drug development programs through the clinical trial process as required by the FDA and to develop our commercial products business. We also need additional long-term financing to support future operations and capital expenditures, including capital for additional personnel and facilities. If we spend more money than currently expected for our drug development programs and our commercial products business, we will need to raise additional capital by selling debt or equity securities, by entering into strategic relationships or through other arrangements. We may be unable to raise any additional amounts on reasonable terms or when they are needed due to the volatile nature of the biotechnology marketplace. If we are unable to raise this additional capital, we may have to delay or postpone critical clinical studies or abandon other development programs.

Our stock price could be volatile, which could cause you to lose part or all of your investment.

The market price of our common stock, like that of the common stock of many other development stage biotechnology companies, is highly volatile. In addition, the stock market has experienced extreme price and volume fluctuations. This volatility has significantly affected the market prices of securities of many biotechnology and pharmaceutical companies for reasons frequently unrelated to or disproportionate to the operating performance of the specific companies. These broad market fluctuations may adversely affect the market price of our common stock.

Anti-takeover provisions may deter a third party from acquiring us, limiting our stockholders’ ability to profit from such a transaction.

Our Board of Directors has the authority to issue up to 5,000,000 shares of preferred stock, of which 40,000 have been reserved for issuance in connection with our stockholder rights plan, and to determine the price, rights, preferences and privileges of those shares without any further vote or action by our stockholders. We also adopted a “poison pill” stockholder rights plan that will dilute the stock ownership of acquirers of our common stock upon the occurrence of certain events. This stockholder rights plan could have the effect of making it more difficult for a third party to acquire a majority of our outstanding voting stock.

We are subject to the anti-takeover provisions of Section 203 of the Delaware General Corporation Law, which prohibits us from engaging in a “business combination” with an “interested stockholder” for a period of

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three years after the date of the transaction in which the person becomes an interested stockholder, unless the business combination is approved in a prescribed manner. This provision could have the effect of delaying or preventing a change of control of the Company. Section 203 and the stockholder rights plan may have the effect of deterring hostile takeovers or delaying or preventing changes in our management, including transactions in which stockholders might otherwise receive a premium for their shares over then current market prices.

Changes in the securities laws and regulations have increased, and are likely to continue to increase our costs.

The Sarbanes-Oxley Act of 2002, which became law in July 2002, has required changes in some of our corporate governance, securities disclosure and compliance practices. In response to the requirements of that Act, the SEC and the Nasdaq have promulgated new rules and listing standards covering a variety of subjects. Compliance with these new rules and listing standards have increased our legal costs and financial and accounting costs, and we expect these increased costs to continue. Likewise, these developments may make it more difficult for us to attract and retain qualified members of our board of directors, particularly independent directors.

Item 1B. Unresolved Staff Comments

NONE

Item 2. PROPERTIES.

We lease approximately 27,500 square feet of space in Waltham, Massachusetts, of which approximately 12,500 square feet is manufacturing and laboratory space. The remaining space is used as office space. Our leases expire by January 2013, with options to extend for two five-year periods. During fiscal 2007, we incurred aggregate rental costs for our facility, excluding maintenance, taxes and utilities, of approximately $389,000.

Item 3. LEGAL PROCEEDINGS.

Imclone Systems

In July 2006, Repligen reported that the United States District Court for the District of Massachusetts issued a Summary Judgment ruling in favor of Repligen and The Massachusetts Institute of Technology (“MIT”) and rejected ImClone Systems Incorporated’s (“Imclone”) defense of patent exhaustion in the ongoing patent infringement lawsuit over the production of Erbitux^®. In their complaint, Repligen and MIT allege that ImClone’s production of Erbitux^® infringes U.S. patent 4,663,281 which covers certain genetic elements that increase protein production in a mammalian cell. This patent is assigned to MIT and exclusively licensed to Repligen.

ImClone had previously reported that it produced approximately $1 billion worth of Erbitux^® prior to the expiration of the patent-in-suit in 2004 and that Bristol-Myers Squibb, ImClone’s commercial partner, has paid ImClone $900 million in up-front and milestone payments as well as a 39% royalty on the net sales of Erbitux^® in the United States.

Repligen and MIT allege that the cell line that ImClone uses to produce Erbitux^® employs key technology that is claimed in the patent-in-suit. Repligen and MIT also allege that the cell line was created under contract for the National Cancer Institute (“NCI”) by a predecessor to Repligen and subsequently transferred from the NCI to ImClone for use in research and development only. In its ruling, the Court found that neither the transfer to the NCI by Repligen’s predecessor nor the subsequent transfer to ImClone by the NCI exhausted the proprietary rights of Repligen and MIT. The Court’s ruling has eliminated these arguments as a potential defense for ImClone at trial. Repligen and MIT intend to seek damages adequate to compensate Repligen and MIT for ImClone’s unlicensed use of the patented technology and a multiplier of any such damage award based on ImClone’s willful infringement. The outcome of this case is undeterminable at this time.

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Bristol-Myers Squibb Company (“Bristol”)

In January 2006, Repligen Corporation and The University of Michigan jointly filed a complaint against Bristol in the United States District Court for the Eastern District of Texas for infringement of U.S. Patent No. 6,685,941 (“the ‘941 patent”) for the commercial sale of Orencia^®. The ‘941 patent, entitled “Methods of Treating Autoimmune Disease via CTLA4-Ig,” covers methods of using CTLA4-Ig to treat rheumatoid arthritis, as well as other therapeutic methods. Repligen has exclusive rights to this patent from its owners, the University of Michigan and the U.S. Navy. In February 2006, Bristol answered the complaint and counterclaimed seeking a declaratory judgment that the ‘941 patent is invalid and unenforceable and that Bristol does not infringe the patent. On November 16, 2006, the Court held a scheduling conference. Jury selection for the trial in this matter is scheduled to commence on April 7, 2008. The outcome of this case is undeterminable at this time.

Other

From time to time, we may be subject to other legal proceedings and claims in the ordinary course of business. We are not currently aware of any such proceedings or claims that we believe will have, individually or in the aggregate, a material adverse effect on our business, financial condition or results of operations.

Item 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

No matters were submitted to a vote of the security holders of the Company through the solicitation of proxies or otherwise, during the last quarter of the fiscal year ended March 31, 2007.

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PART II

Item 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES.

Market Information

Our common stock is traded on the Nasdaq Global Market under the symbol “RGEN.” The following table sets forth for the periods indicated the high and low closing prices for the common stock as reported by Nasdaq.

	Fiscal Year 2007				Fiscal Year 2006
	High		Low		High		Low
First Quarter	$	3.82	$	2.58	$	2.45	$	1.67
Second Quarter	$	3.40	$	2.27	$	4.00	$	1.99
Third Quarter	$	3.41	$	2.70	$	4.00	$	2.80
Fourth Quarter	$	3.30	$	2.80	$	4.99	$	3.43

Stockholders and Dividends

As of June 1, 2007 there were approximately 790 stockholders of record of our common stock. We have not paid any dividends since our inception and do not intend to pay any dividends on our common stock in the foreseeable future. We anticipate that we will retain all earnings, if any, to support our operations and our proprietary drug development programs. Any future determination as to the payment of dividends will be at the sole discretion of our board of directors and will depend on our financial condition, results of operations, capital requirements and other factors our board of directors deems relevant.

Issuer Purchases of Equity Securities

We purchased, by means of employee forfeiture, 10,000 shares of unvested restricted stock during the year ended March 31, 2007 at an average price of $0.01 in connection with the termination of employment by the holder of such restricted stock.

Equity Compensation Plan Information

See Part III, Item 12 for information regarding securities authorized for issuance under our equity compensation plans.

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Item 6. SELECTED FINANCIAL DATA

The following selected financial data are derived from the audited financial statements of Repligen. The selected financial data set forth below should be read in conjunction with our financial statements and the related notes thereto and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included elsewhere in this report and our Annual Report on Form 10-K for the years ended March 31, 2006, 2005, 2004 and 2003.

	Years ended March 31,
	2007			2006			2005			2004			2003
	(In thousands except per share amounts)
Revenue:
Product revenue	$	13,074		$	12,529		$	9,360		$	6,843		$	7,743
Other revenue		1,000			382			—			71			29
Total revenue		14,074			12,911			9,360			6,914			7,772
Operating expenses:
Cost of product revenue		3,615			3,551			3,888			3,248			3,480
Research and development		5,924			5,163			5,037			6,484			5,227
Selling, general and administrative		6,360			5,417			4,597			4,710			4,159
Impairment of long lived asset		—			—			—			2,413			—
Total operating expenses		15,899			14,131			13,522			16,855			12,866
Income (loss) from operations		(1,825	)		(1,220	)		(4,162	)		(9,941	)		(5,094	)
Interest expense		(11	)		(3	)		—			—			—
Investment income		947			750			428			390			557
Other income		—			1,170			750			—			—
Net income (loss)	$	(889	)	$	697		$	(2,984	)	$	(9,551	)	$	(4,537	)
Earnings Per Share:
Basic and diluted	$	(0.03	)	$	0.02		$	(0.10	)	$	(0.32	)	$	(0.17	)
Weighted average shares outstanding:
Basic		30,379			30,125			30,062			29,686			26,813
Diluted		30,379			30,691			30,062			29,686			26,813
	As of March 31,
	2007			2006			2005			2004			2003
	(In thousands)
Balance Sheet Data:
Cash and marketable securities*	$	22,627		$	23,408		$	23,523		$	24,269		$	18,709
Working capital		22,394			18,575			15,673			13,684			15,602
Total assets		29,076			28,599			27,607			29,615			26,793
Long-term obligations		200			231			120			86			2
Accumulated deficit		(157,683	)		(156,794	)		(157,491	)		(154,507	)		(144,956	)
Stockholders’ equity		25,538			25,433			24,290			27,164			24,550

* Excludes restricted cash of $200,000 restricted as part of our headquarters lease arrangement for all years presented.

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Item 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS.

This annual report on Form 10-K contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, and Section 21E of the Securities Exchange Act of 1934. The forward-looking statements in this annual report on Form 10-K do not constitute guarantees of future performance. Investors are cautioned that statements in this annual report on Form 10-K that are not strictly historical statements, including, without limitation, statements regarding current or future financial performance, potential impairment of future earnings, management’s strategy, plans and objectives for future operations and product candidate acquisition, clinical trials and results, litigation strategy, product research and development, research and development expenditures, intellectual property, development and manufacturing plans, availability of materials and product and adequacy of capital resources and financing plans constitute forward-looking statements. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from those anticipated, including, without limitation, the risks identified under the caption “Risk Factors” and other risks detailed in this annual report on Form 10-K and our other filings with the Securities and Exchange Commission. We assume no obligation to update any forward-looking information contained in this annual report on Form 10-K.

Overview

We are a biopharmaceutical company focused on the development of novel therapeutics for diseases that affect the central nervous system. A number of drug development programs are currently being conducted to evaluate our drug candidates in diseases such as bipolar disorder and neurodegeneration. In addition, we sell two commercial products, Protein A for monoclonal antibody purification and SecreFlo^® for assessment of pancreatic disorders. In fiscal 2007, we experienced growth in sales and profits from our commercial products business. Our business strategy is to deploy the profits from our current commercial products and any revenue that we may receive from our patents to enable us to invest in the development of our product candidates in the treatment area of neurological diseases while reducing our financial risk.

CRITICAL ACCOUNTING POLICIES AND ESTIMATES

While our significant accounting polices are more fully described in notes to our financial statements, we have identified the policies and estimates below as critical to our business operations and the understanding of our results of operations. The impact and any associated risks related to these policies on our business operations is discussed throughout “Management’s Discussion and Analysis of Financial Condition” and “Results of Operations” where such policies affect our reported and expected financial results.

Revenue Recognition

We apply Staff Accounting Bulletin No. 104, “Revenue Recognition” (“SAB No. 104”) to our revenue arrangements. We generate product revenues from the sale of our Protein A products to customers in the pharmaceutical and process chromatography industries and from the sale of SecreFlo^® to hospital-based gastroenterologists. In accordance with SAB No. 104, we recognize revenue related to product sales upon delivery of the product to the customer as long as there is persuasive evidence of an arrangement, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Determination of whether these criteria have been met are based on management’s judgments primarily regarding the fixed nature of the fee charged for product delivered, and the collectibility of those fees. We have a few longstanding customers who comprise the majority of our revenue and have excellent payment history. We have had no significant write-offs of uncollectible invoices in the periods presented. Should changes in conditions cause management to determine that these criteria are not met for certain future transactions, revenue recognized for any reporting period could be adversely affected.

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At the time of sale, we also evaluate the need to accrue for warranty and sales returns. The supply agreements we have with our customers and related purchase orders identify the terms and conditions of each sale and the price of the goods ordered. Due to the nature of our sales arrangements, inventory produced for sale is tested for quality specifications prior to shipment. Since the product is manufactured to order and in compliance with required specifications prior to shipment, the likelihood of sales return, warranty or other issues is largely diminished. Sales returns and warranty issues are infrequent and have had nominal impact on our financial statements historically. Should changes in conditions cause management to determine that warranty, returns or other sale-related reserves are necessary for certain future transactions, revenue recognized for any reporting period could be adversely affected.

During the fiscal years ended March 31, 2007 and March 31, 2006, we recognized $825,000 and $310,000, respectively of revenue from a sponsored research and development project under an agreement with the Stanley Medical Research Institute (SMRI). Research revenue is recognized on a cost plus fixed-fee basis when the expense has been incurred and services have been performed. Determination of which costs incurred qualify for reimbursement under the terms of our contractual agreement and the timing of when such costs were incurred involves the judgment of management. Our calculations are based upon the agreed-upon terms as stated in our arrangement. However, should our estimated calculations change or be challenged by SMRI, research revenue may be adjusted in subsequent periods. Our calculations have not historically changed or been challenged and we do not anticipate any subsequent change in our revenue related to this sponsored research and development project.

Additionally, during fiscal years 2007 and 2006, the Company earned and recognized approximately $175,000 and $72,000, respectively in royalty revenue from ChiRhoClin. Revenues earned from ChiRhoClin royalties are recorded in the periods when they are earned based on royalty reports sent by ChiRhoClin to the Company.

There have been no material changes to our initial estimates related to revenue recognition in any periods presented in the accompanying financial statements.

Inventories

Inventories relate to our Protein A business. We value inventory at cost or, if lower, fair market value. We determine cost using the first-in, first-out method. We review our inventories at least quarterly and record a provision for excess and obsolete inventory based on our estimates of expected sales volume, production capacity and expiration dates of raw materials, work-in process and finished goods. Expected sales volumes are determined based on supply forecasts provided by our key customers for the next three to twelve months. We write down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value, and inventory in excess of expected requirements to cost of goods sold. Manufacturing of Protein A finished goods is done to order and tested for quality specifications prior to shipment.

A change in the estimated timing or amount of demand for our products could result in additional provisions for excess inventory quantities on hand. Any significant unanticipated changes in demand or unexpected quality failures could have a significant impact on the value of our inventory and reported operating results. During all periods presented in the accompanying financial statements, there has been no material adjustments related to a revised estimate of inventory valuations.

Accrued Liabilities

We prepare our financial statements in accordance with accounting principles generally accepted in the United States. These principles require that we estimate accrued liabilities. This process involves identifying services, which have been performed on our behalf, and estimating the level of service performed and the associated cost incurred for such service as of each balance sheet date. Examples of estimated accrued expenses

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include: 1) Fees paid to our contract manufacturers in conjunction with the production of clinical materials. These expenses are normally determined through a contract or purchase order issued by the Company; 2) Service fees paid to organizations for their performance in conducting our clinical trials. These expenses are determined by contracts in place for those services and communications with project managers on costs which have been incurred as of each reporting date; and 3) Professional and consulting fees incurred with law firms, audit and accounting service providers and other third party consultants. These expenses are determined by either requesting those service providers to estimate unbilled services at each reporting date for services incurred, or tracking costs incurred by service providers under fixed fee arrangements. We have processes in place to estimate the appropriate amounts to record for accrued liabilities, which principally involve the applicable personnel reviewing the services provided. In the event that we do not identify certain costs which have begun to be incurred or we under or over-estimate the level of services performed or the costs of such services, our reported expenses for that period may be too low or too high. The date on which certain services commence, the level of services performed on or before a given date, and the cost of such services are often judgmental. We make these judgments based upon the facts and circumstances known to us at the date of the financial statements.

A change in the estimated cost or volume of services provided could result in additional accrued liabilities. Any significant unanticipated changes in such estimates could have a significant impact on our accrued liabilities and reported operating results. There has been no material adjustments to our accrued liabilities in any of the periods presented in the accompanying financial statements.

Stock-Based Compensation

Effective April 1, 2006, we adopted the fair value recognition provisions of Statement of Financial Accounting Standards No. 123R, “Share-Based Payment—An Amendment of FASB Statements No. 123 and 95,” or SFAS No. 123R, using the modified prospective transition method. Under this transition method, compensation cost recognized in the statement of operations for the year ended March 31, 2007 includes: (a) compensation cost for all share-based payments granted prior to, but not yet vested as of April 1, 2006, based on the grant-date fair value estimated in accordance with the original provisions of SFAS No. 123 and (b) compensation cost for all share-based payments granted, modified or settled subsequent to April 1, 2006, based on the grant-date fair value estimated in accordance with the provisions of SFAS No. 123R. In accordance with the modified prospective transition method, results for prior periods have not been restated.

Effective with the adoption of SFAS No. 123R, we have elected to use the Black-Scholes option pricing model to calculate the fair value of share-based awards on the grant date.

The expected term of options granted represents the period of time for which the options are expected to be outstanding and is derived from our historical stock option exercise experience and option expiration data. For option grants made subsequent to the adoption of SFAS No. 123R, the expected life of stock options granted is based on the simplified method allowable under SAB No. 107. Accordingly, the expected term is presumed to be the midpoint between the vesting date and the end of the contractual term. In addition, for purposes of estimating the expected term, we have aggregated all individual option awards into one group as we do not expect substantial differences in exercise behavior among its employees. The expected volatility is a measure of the amount by which our stock price is expected to fluctuate during the expected term of options granted. We determined the expected volatility solely based upon the historical volatility of our Common Stock over a period commensurate with the option’s expected term. We do not believe that the future volatility of our Common Stock over an option’s expected term is likely to differ significantly from the past. The risk-free interest rate is the implied yield available on U.S. Treasury zero-coupon issues with a remaining term equal to the option’s expected term on the grant date. We have never declared or paid any cash dividends on any of our capital stock and do not expect to do so in the foreseeable future. Accordingly, we use an expected dividend yield of zero to calculate the grant-date fair value of a stock option.

We recognize compensation expense on a straight-line basis over the requisite service period based upon options that are ultimately expected to vest, and accordingly, such compensation expense has been adjusted by an

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amount of estimated forfeitures. Forfeitures represent only the unvested portion of a surrendered option. SFAS No. 123R requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Prior to the adoption of SFAS No. 123R, we accounted for forfeitures upon occurrence as permitted under SFAS No. 123. Based on an analysis of historical data, we have calculated an 8% annual forfeiture rate for non-director level employees, a 3% annual forfeiture rate for director- level employees, and a 0% forfeiture rate for non-employee members of the Board of Directors, which we believe is a reasonable assumption to estimate forfeitures. However, the estimation of forfeitures requires significant judgment, and to the extent actual results or updated estimates differ from our current estimates, such amounts will be recorded as a cumulative adjustment in the period estimates are revised.

Prior to April 1, 2006, we applied the pro forma disclosure requirements under SFAS No. 123 and accounted for our stock-based employee compensation plans using the intrinsic value method under the recognition and measurement provisions of Accounting Principles Board Opinion No. 25, “Accounting for Stock Issued to Employees,” (“APB No. 25”) and related interpretations. Accordingly, no stock-based employee compensation cost was recognized in the statement of operations for the year ended March 31, 2006, as all stock options granted under our existing stock plans had an exercise price equal to the market value of the underlying Common Stock on the date of grant.

For the year ended March 31, 2007, we recorded stock-based compensation expense of approximately $837,000 for stock options granted under the Amended and Restated 2001 Repligen Corporation Stock Plan. Basic and diluted earnings per share amounts for the year ended March 31, 2007 were decreased by $0.03, as a result of the adoption of SFAS No. 123R.

As of March 31, 2007, there was $1,275,000 of total unrecognized compensation cost related to unvested share-based awards. This cost is expected to be recognized over a weighted average remaining requisite service period of 2.86 years. The Company expects approximately 671,000 of unvested outstanding options to vest over the next five years.

RESULTS OF OPERATIONS

The following discussion of the financial condition and results of operations should be read in conjunction with the accompanying financial statements and the related footnotes thereto.

Revenues

Total revenue for fiscal 2007, 2006 and 2005 were $14,074,000, $12,911,000 and $9,360,000. Revenues for the years ending March 31, 2007, 2006 and 2005 were primarily comprised of sales of our commercial products, Protein A and SecreFlo^®. During the fiscal year ended March 31, 2007, 2006 and 2005 sales of our commercial products were:

	Year ended March 31						% Change
	2007		2006		2005		2007 vs. 2006		2006 vs. 2005
	(in thousands, except percentages)
Protein A	$	11,127	$	10,540	$	7,134	6	%	48	%
SecreFlo®		1,947		1,989		2,189	-2	%	-9	%
Other product revenue		—		—		37
Product revenue	$	13,074	$	12,529	$	9,360	4	%	34	%

Substantially all of our products based on recombinant Protein A are sold to customers who incorporate our manufactured products into their proprietary antibody purification systems to be sold directly to the pharmaceutical industry. Monoclonal antibodies are a well-established class of drug with applications in rheumatoid arthritis, asthma, Crohn’s disease and a variety of cancers. Sales of Protein A are therefore impacted

24

by the timing of large-scale production orders and on the regulatory approvals for such antibodies, which may result in significant quarterly fluctuations.

During fiscal 2007, Protein A sales increased by $587,000 or 6% over fiscal 2006. We shipped 13% less volume of Protein A in fiscal 2007 compared to fiscal 2006. The decrease in volume however did not reduce revenue compared to fiscal 2006, as the mix of products sold had more favorable pricing resulting in a 19% positive impact on total revenue. The company sells different Protein A products at different price points. The mix of products sold varies and impacts the fluctuations in total sales revenue from year to year.

During fiscal 2006, Protein A sales increased by $3,406,000 or 48%, primarily as a result of a rise in the demand for our Protein A products. The increase in sales volume of Protein A resulted in an increase in revenues of 49%. This increase was slightly offset by a decrease in the total sales price of those products, which had an unfavorable impact of 1% on total revenues.

We anticipate that sales of Protein A will grow in the future and will continue to be subject to quarterly fluctuations due to timing of large-scale production orders.

Sales of SecreFlo^® decreased $42,000 or 2% in fiscal 2007 primarily as a result of direct competition with CRC, our sole supplier of SecreFlo^® and reduced sales and marketing efforts. Decreases in sales volume impacted sales by 1% of the prior year’s total. To remain competitive with CRC, we reduced sales prices, which resulted in an unfavorable impact of 1% on SecreFlo^® revenues.

Sales of SecreFlo^® decreased $200,000 or 9% in fiscal 2006 primarily as a result of direct competition with our sole supplier of SecreFlo^®, the reduction of sales price to remain competitive and as a result of a reduction in sales and marketing efforts. Competition with our sole supplier of SecreFlo^® decreased the volume of SecreFlo^® vials sold, unfavorably impacting revenue by 3%. To remain competitive, we reduced sales prices, which caused an unfavorable impact of 6% on SecreFlo^® revenues.

The settlement in fiscal 2005 with our sole supplier of SecreFlo^® provides for a certain amount of vials of product that we can ultimately ship. The last shipment of SecreFlo^® to the Company from ChiRhoClin should be in late calendar year 2007 and is expected to allow us to fill sales orders into fiscal year 2009. We expect SecreFlo^® revenues will decline by one third in fiscal 2008 as we continue to reduce sales and marketing efforts and focus our sales efforts on key customers.

During the fiscal year 2007 and 2006, we recognized $825,000 and $310,000, respectively, of revenue from a sponsored research and development project under an agreement with the Stanley Medical Research Institute. Research revenue is recognized for costs plus fixed-fee contracts as costs are incurred. Additionally, during fiscal year 2007 and 2006, we earned and recognized approximately $175,000 and $72,000, respectively in royalty revenue from ChiRhoClin . We expect that total research and license revenues will decline moderately in fiscal 2008.

Costs and Operating expenses

Total costs and operating expenses for fiscal 2007, 2006 and 2005 were approximately $15,899,000, $14,131,000 and $13,522,000, respectively.

	2007		2006		2005		2007 vs. 2006		2006 vs. 2005
Costs and operating expenses:
Cost of product revenue	$	3,615	$	3,551	$	3,888	2	%	-9	%
Research and development		5,924		5,163		5,037	15	%	3	%
Selling, general and administrative		6,360		5,417		4,597	17	%	18	%
Total operating expenses	$	15,899	$	14,131	$	13,522	13	%	5	%

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The increase in cost of product revenue of $64,000 or 2% in fiscal 2007 is attributable to several factors. These include an increase of $163,000 in consulting costs and a $128,000 increase in occupancy and depreciation costs. Consulting, occupancy and depreciation costs increased due to the costs associated with implementation of our fermentation facility in fiscal 2007, as well as spending to improve our quality and redundancy systems to meet customer expectations. Additionally, we incurred $26,000 in stock based compensation expense pursuant to the adoption of SFAS No. 123(R) and had an increase in labor costs of $147,000 compared to fiscal 2006. These increases were off-set by a decrease in Protein A material costs of $267,000 related to lower volume of Protein A production in fiscal 2007 compared to fiscal 2006 and lower costs of $39,000 related to SecreFlo^® sales.

The decrease in cost of product revenue of $337,000, or 9%, in fiscal 2006 is attributable to a decrease in royalty and amortization fees of $1,236,000 associated with SecreFlo^®, partially offset by an increase of $688,000 in direct materials and increased personnel costs of $189,000. This reduction in SecreFlo^® related expenses is due to the settlement agreement in May of 2005 with ChiRhoClin. The increase in direct material and personnel costs is a result of growth in production volume and a small increase in the number of employees in the manufacturing department to support the 49% increase in volume of Protein A.

Research and development expenses for fiscal 2007, 2006 and 2005 were approximately $5,924,000, $5,163,000 and $5,037,000, respectively. Research and development costs primarily include costs of internal personnel, external research collaborations, clinical trials and the costs associated with the manufacturing and testing of clinical materials. We currently have ongoing research and development programs that support our product candidates of secretin and uridine. In addition, we are involved with a number of early stage programs that may or may not be further developed. Due to the small size of the Company and the fact that these various programs share personnel and fixed costs such as facility costs, depreciation, and supplies, we do not track our expenses by program.

Each of our research and development programs is subject to risks and uncertainties, including the requirement to seek regulatory approvals that are outside of our control. For example, our clinical trials may be subject to delays based on our inability to enroll patients at the rate that we expect to meet the schedule for our planned clinical trials. Moreover, the product candidates identified in these research programs, particularly in our early stage programs must overcome significant technological, manufacturing and marketing challenges before they can be successfully commercialized. For example, results from our preclinical animal models may not be replicated in our clinical trials with humans. As a result of these risks and uncertainties, we are unable to predict with any certainty the period in which material net cash inflows from such projects could be expected to commence or the completion date of these programs.

These risks and uncertainties also prevent us from estimating with any certainty the specific timing and future costs of our research and development programs, although historical trends within the industry suggest that expenses tend to increase in later stages of development. Collaborations with commercial vendors and academic researchers accounted for 40%, 36%, and 37% of our research and development expenses in the fiscal years ended March 31, 2007, 2006 and 2005, respectively. The outsourcing of such services provides us flexibility to discontinue or increase spending depending on the success of our research and development programs.

Research and development expenses increased by $761,000, or 15%, during fiscal 2007. This increase is largely attributable to higher clinical trial expenses of $959,000, as the Company enrolled the majority of the patients in our two clinical trial programs for Uridine for bipolar disorder and Secretin for diagnostic imaging. Additionally there were increased personnel expenses of $66,000 due to slightly higher headcount and the Company incurred stock based compensation expense pursuant to the adoption of SFAS No. 123(R) in fiscal 2007 of $229,000. These increases were offset by reductions in external research expenses of $465,000. This was due to a reduction in activities related to secretin drug manufacturing compared to fiscal 2006.

Research and development expenses increased by $126,000, or 3%, during fiscal 2006. This increase is largely attributable to higher clinical trial expenses of $192,000 as the Company had two clinical trial programs

26

in fiscal 2006 for Uridine for bipolar disorder and Secretin for diagnostic imaging that exceeded the clinical trial programs in fiscal 2005 which primarily consisted of the Secretin for schizophrenia trial. There were increased personnel expenses of $124,000 due to the addition of one clinical staff person to support the increase in clinical trials and increased license expenses of $59,000 due to a new license with another company for research materials for future clinical development. These increased expenses were offset by decreased expenses associated with our external research of $222,000 due to decreased non-recurring pharmacology studies on two of our research compounds. Clinical material expenses were relatively unchanged from fiscal 2005 to fiscal 2006.

Future research and development expenses are dependent on a number of variables, including the cost and design of clinical trials and external costs such as manufacturing of clinical materials. We expect our research and development expenses in fiscal 2008 to increase due to clinical trial expenses as the Company continues studies for secretin for diagnostic imaging, continues drug manufacturing activities for secretin and begins the Friedreich’s Ataxia research and development program which was recently licensed by the Company. Additionally, there may be further increases in expenses if we acquire additional product candidates.

Selling, general and administrative expenses (SG&A) include the associated costs with selling our commercial products and costs required to support our research and development efforts including legal, accounting, patent, shareholder services and other administrative functions. In addition, SG&A expenses have historically included costs associated with various litigation matters.

During fiscal 2007, SG&A costs increased by approximately $943,000 or 17%. This increase was mainly the result of the stock based compensation expense recorded pursuant to the adoption of SFAS No. 123(R) of $582,000 and personnel expenses which increased by $287,000 due to compensation and benefit increases. Investor relation expenses also increased $78,000 due to expanded outreach to the investment community. Legal expenses were consistent with fiscal 2006 as we continue to prosecute patent infringement lawsuits against Bristol and Imclone.

During fiscal 2006, SG&A costs increased by approximately $820,000, or 18%. This increase was partly the result of increased personnel expenses of $291,000 due to the addition of two senior managers to support our growing business. Additionally, professional expenses increased $271,000 related to recruiting expenses for the new senior management and increased external investor relations consulting for the Company to expand awareness in the investor community. Legal expenses increased by $176,000 due to the Company filing suit against Bristol for patent infringement and continued expenses supporting the patent infringement suit against Imclone.

We expect SG&A expenses to increase in fiscal 2008 due to anticipated increases in litigation expenses for the Bristol and Imclone cases combined with higher headcount and the related personnel expenses.

Investment income

Investment income includes income earned on invested cash balances. Investment income for fiscal 2007, 2006 and 2005 was approximately $948,000, $750,000 and $428,000, respectively. The increase of $198,000 or 21% is attributable to higher interest rates. The increase of $322,000 or 75% in fiscal 2006 is attributable to higher interest rates compared to fiscal 2005. We expect interest income to vary based on changes in the amount of funds invested and fluctuation of interest rates.

Other income

During the year ended March 31, 2006, Repligen entered into a Settlement Agreement with ChiRhoClin, in full settlement of their arbitration proceedings. As a result of the settlement, we determined that we were not required to pay approximately $1,170,000 of previously accrued but unremitted royalties to ChiRhoClin related to SecreFlo^® sales from February 2004 to March 2005. This amount, which was accrued at March 31, 2005, was reversed at the time of settlement and is recorded as other income in the fiscal year ended March 31, 2006.

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Liquidity and Capital Resources

We have financed our operations primarily through sales of equity securities and revenues derived from product sales and grants. Our revenue for the foreseeable future will be limited to our product revenue related to Protein A and SecreFlo^®. Revenues derived from the sales of SecreFlo^® vials are expected only through calendar year 2009. Given the uncertainties related to pharmaceutical product development, we are currently unable to reliably estimate when, if ever, our therapeutic product candidates or our patents will generate revenue and cash flows.

At March 31, 2007, we had cash and marketable securities of $22,627,000 compared to $23,408,000 at March 31, 2006. Deposits for leased office space of $200,000 is classified as restricted cash and is not included in cash and marketable securities total for either 2007 or 2006.

Cash Flows

(In thousands)	Year ended March 31,
Cash provided by (used in)	2007		Increase / (Decrease)			2006		Increase / (Decrease)		2005
Operating Activities	$	405	$	(10	)	$	415	$	1,528	$	(1,113	)
Investing Activities		1,775		311			1,464		1,119		345
Financing Activities		118		(215	)		333		307		26

Operating Activities

In fiscal 2007, our operating activities provided cash of $405,000 which reflects a net loss of approximately $889,000 which includes non-cash charges totaling approximately $1,376,000 including depreciation, amortization and stock based compensation charges. The remaining cash flow from operations resulted from favorable changes in various working capital accounts.

In fiscal 2006, our operating activities provided cash of $415,000 as a result of our net profit of $697,000 and non-cash charges such as depreciation, amortization and stock compensation charges. Sources of cash included a decrease in accounts receivable of approximately $176,000 due to improved cash collections and a reduction in prepaid expenses of approximately $134,000. Uses of cash included an increase in inventories of approximately $832,000 which was a result of purchases related to a manufacturing process conversion and a decrease in accrued liabilities of approximately $328,000.

Investing Activities

In fiscal 2007, investing activities included capital spending of $1,327,000 mainly related to the new fermentation facility in Waltham, Massachusetts. In fiscal 2006, our purchases of property, plant and equipment were $877,000 of which $142,000 was financed through capital leases. Purchases and redemptions of marketable securities account for the remainder of the fluctuation during fiscal 2007 and fiscal 2006. We generally place our marketable security investments in high quality credit instruments as specified in our investment policy guidelines.

Financing Activities

In fiscal 2007, exercises of stock options provided cash proceeds of $158,000. In fiscal 2006, exercises of stock options provided cash proceeds of $340,000.

Off-Balance Sheet Arrangements

We do not have any special purpose entities or off-balance sheet financing arrangements.

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Contractual Obligations

As of March 31, 2007, we had the following fixed obligations and commitments:

	Payments Due By Period
	Total		Less than 1 Year		1 – 3 Years		3 – 5 Years		More than 5 Years
	(In thousands)
Operating lease obligations	$	2,211	$	449	$	928	$	834	$	—
Capital lease obligations (1)		125		40		85		—		—
Purchase obligations (2)		298		298		—		—		—
Contractual obligations (3)		324		99		104		96		25
Total	$	2,958	$	886	$	1,117	$	930	$	25

(1) The above amounts represent principal payments only while principal and interest are payable through a fixed monthly payment of approximately $4,000 and a fixed annual payment of $52,000.

(2) This amount represents minimum commitments due under a third-party manufacturing agreement.

(3) These amounts include payments for license, supply and consulting agreements.

Capital Requirements

Our future capital requirements will depend on many factors, including the following:

• the success of our clinical studies;

• the scope of and progress made in our research and development activities;

• our ability to acquire additional product candidates;

• the success of any proposed financing efforts; and

• the ability to sustain sales and profits of our commercial products.

Absent an acquisition of another product candidate, we believe our current cash balances are adequate to meet our cash needs for at least the next twenty-four months. We expect to incur an increased level of expense in fiscal 2008 compared to those incurred in fiscal 2007. This is due to anticipated increases in clinical study expenses and legal fees for litigation in process currently, as well as increased personnel expenses. Our future capital requirements include, but are not limited to, continued investment in our research and development programs, capital expenditures primarily associated with purchases of equipment and continued investment in our intellectual property portfolio.

We plan to continue to invest in key research and development activities. We continue to seek to acquire such potential assets that may offer us the best opportunity to create value for our shareholders. In order to acquire such assets, we may need to seek additional financing to fund these investments. This may require the issuance or sale of additional equity or debt securities. The sale of additional equity may result in additional dilution to our stockholders. Should we need to secure additional financing to acquire a product, fund future investment in research and development, or meet our future liquidity requirements, we may not be able to secure such financing, or obtain such financing on favorable terms because of the volatile nature of the biotechnology marketplace.

Net Operating Loss Carryforwards

At March 31, 2007, we had net operating loss carryforwards of approximately $100,130,000 and research and development credit carryforwards of approximately $5,270,000 to reduce future federal income taxes, if any. The net operating loss and tax credit carryforwards have expired and will continue to expire at various dates, beginning in fiscal year 2008, if not used. Net operating loss carryforwards and available tax credits are subject

29

to review and possible adjustment by the Internal Revenue Service and may be limited in the event of certain changes in the ownership interest of significant stockholders. We did not record a tax provision in the fiscal year 2007 statement of operations as we did not generate taxable income.

Effects of Inflation

Our assets are primarily monetary, consisting of cash, cash equivalents and marketable securities. Because of their liquidity, these assets are not directly affected by inflation. Since we intend to retain and continue to use our equipment, furniture and fixtures and leasehold improvements, we believe that the incremental inflation related to replacement costs of such items will not materially affect our operations. However, the rate of inflation affects our expenses, such as those for employee compensation and contract services, which could increase our level of expenses and the rate at which we use our resources.

Recent Accounting Pronouncements

Accounting for Uncertainty in Income Taxes

In June 2006, the Financial Accounting Standards Board (FASB) issued FASB Interpretation No. 48, “Accounting for Uncertainty in Income Taxes—an Interpretation of FASB Statement No. 109” (the “Interpretation”). The Interpretation clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” The Interpretation prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This Interpretation also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The Interpretation is effective for fiscal years beginning after December 15, 2006. The Company has not yet completed its evaluation of the Interpretation, but does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

Fair Value Measurements

In September 2006, the FASB issued FASB Statement No. 157 “Fair Value Measurements” (SFAS No. 157). SFAS No. 157 establishes a common definition for fair value, creates a framework for measuring fair value, and expands disclosure requirements about such fair value measurements. SFAS No. 157 is effective for our first quarter of 2008. Management does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

Fair Value Option for Financial Assets and Financial Liabilities

In February 2007, the FASB issued FASB Statement No. 159, “The Fair Value Option for Financial Assets and Financial Liabilities” (SFAS No. 159). SFAS No. 159 provides companies with an option to report selected financial assets and liabilities at fair value. The objective of SFAS No. 159 is to reduce both complexity in accounting for financial instruments and the volatility in earnings caused by measuring related assets and liabilities differently. Generally accepted accounting principles have required different measurement attributes for different assets and liabilities that can create artificial volatility in earnings. FASB has indicated it believes that SFAS No. 159 helps to mitigate this type of accounting-induced volatility by enabling companies to report related assets and liabilities at fair value, which would likely reduce the need for companies to comply with detailed rules for hedge accounting. SFAS No. 159 also establishes presentation and disclosure requirements designed to facilitate comparisons between companies that choose different measurement attributes for similar types of assets and liabilities. For example, SFAS No. 159 requires companies to provide additional information that will help investors and other users of financial statements to more easily understand the effect of the company’s choice to use fair value on its earnings. It also requires entities to display the fair value of those assets and liabilities for which the company has chosen to use fair value on the face of the balance sheet. SFAS No. 159

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does not eliminate disclosure requirements included in other accounting standards, including requirements for disclosures about fair value measurements included in FASB Statement No. 157, “Fair Value Measurements” (SFAS No. 157), and FASB Statement No. 107, “Disclosures about Fair Value of Financial Instruments” (SFAS No. 107). SFAS No. 159 is effective as of the beginning of a company’s first fiscal year beginning after November 15, 2007. Early adoption is permitted as of the beginning of the previous fiscal year provided that the company makes that choice in the first 120 days of that fiscal year and also elects to apply the provisions of SFAS No. 157. The Company has not yet completed its evaluation of the Interpretation, but does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

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Item 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Interest Rate Risk

We have investments in commercial paper, U.S. Government and agency securities as well as corporate bonds and other debt securities. As a result, we are exposed to potential loss from market risks that may occur as a result of changes in interest rates, changes in credit quality of the issuer or otherwise.

We generally place our marketable security investments in high quality credit instruments, as specified in our investment policy guidelines. A hypothetical 100 basis point decrease in interest rates would result in an approximate $55,000 decrease in the fair value of our investments as of March 31, 2007. However, the conservative nature of our investments mitigates our interest rate exposure, and our investment policy limits the amount of our credit exposure to any one issue, issuer (with the exception of U.S. treasury obligations) and type of instrument. We do not expect any material loss from our marketable security investments due to interest rate fluctuations and therefore believe that our potential interest rate exposure is limited. We intend to hold these investments to maturity, in accordance with our business plans.

Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTAL DATA

Financial statements and supplementary data required by Item 8 are set forth at the pages indicated in Item 15(a) below and are incorporated herein by reference.

Item 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

None.

Item 9A. CONTROLS AND PROCEDURES.

(a) Disclosure Controls and Procedures.

The Company’s management, with the participation of our chief executive officer and chief financial officer, has evaluated the effectiveness of the Company’s disclosure controls and procedures (as defined in Rules 13a-15(e) or 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) as of the end of the period covered by this report. Based on such evaluation, our chief executive officer and chief financial officer have concluded that, as of the end of such period, the Company’s disclosure controls and procedures were effective in ensuring that information required to be disclosed by the Company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, on a timely basis, and is accumulated and communicated to the Company’s management, including the Company’s chief executive officer and chief financial officer, as appropriate to allow timely decisions regarding required disclosure.

(b) Management’s Annual Report on Internal Control Over Financial Reporting.

Management of the Company is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is defined in Rule 13a-15(f) and 15d-15(f) under the Exchange Act as a process designed by, or under the supervision of, the Company’s principal executive and principal financial officers and effected by the Company’s board of directors, management and other personnel to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. generally accepted accounting principles and includes those policies and procedures that:

• pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of the assets of the company;

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• provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and

• provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Projections of any evaluation of effectiveness to future periods are subject to the risks that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Management assessed the effectiveness of the company’s internal control over financial reporting as of March 31, 2007. In making this assessment, management used the criteria established in Internal Control-Integrated Framework, issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). Based on this assessment, our management concluded that, as of March 31, 2007, our internal control over financial reporting is effective based on those criteria. Our management’s assessment of the effectiveness of our internal control over financial reporting as of March 31, 2007 has been audited by Ernst & Young LLP, an independent registered public accounting firm, as stated in their report appearing in Item 9A of this Form 10-K.

/s/ REPLIGEN CORPORATION

June 6, 2007

(c) Attestation Report of the Independent Registered Public Accounting Firm.

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Stockholders of Repligen Corporation

We have audited management’s assessment, included in the accompanying Report of Management on Internal Control Over Financial Reporting, that the Company maintained effective internal control over financial reporting as of March 31, 2007, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (the COSO criteria). Repligen Corporation’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting. Our responsibility is to express an opinion on management’s assessment and an opinion on the effectiveness of the Company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, evaluation of management’s assessment, testing and evaluating the design and operating effectiveness of internal control and performing such other procedures, as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the Company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and the receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the Company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, management’s assessment that the Company maintained effective internal control over financial reporting as of March 31, 2007, is fairly stated, in all material respects, based on the COSO criteria. Also, in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of March 31, 2007, based on the COSO criteria.

We also have audited, in accordance with the standards the Public Company Accounting Oversight Board (United States), the balance sheets of Repligen Corporation as of March 31, 2007 and 2006, and the related statements of operations, shareholders’ equity, and cash flows for each of the three years in the period ended March 31, 2007 and our report dated June 6, 2007, expressed an unqualified opinion thereon.

/s/ Ernst & Young LLP

Boston, Massachusetts

June 6, 2007

34

(d) Changes in Internal Control Over Financial Reporting.

There have not been any changes in the Company’s internal control over financial reporting (as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) during the quarter ended March 31, 2007 that have material affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

Item 9B. OTHER INFORMATION

None.

35

PART III

Pursuant to General Instructions G to Form 10-K, the information required for Part III, Items 10, 11,12, 13 and 14, is incorporated herein by reference from the Company’s proxy statement for the Annual Meeting of Stockholders to be held on September 14, 2007.

36

PART IV

Item 15. EXHIBITS, F INANCIAL STATEMENT SCHEDULES

The following documents are filed as part of this Annual Report on Form 10-K:

(a) (1)    Financial Statements:

The financial statements required by this item are submitted in a separate section beginning on page 35 of this Report, as follows:

	Page
Report of Independent Registered Public Accounting Firm	F-2
Balance Sheets as of March 31, 2007 and 2006	F-3
Statements of Operations for the Years Ended March 31, 2007, 2006 and 2005	F-4
Statements of Stockholders’ Equity for the Years Ended March 31, 2007, 2006 and 2005	F-5
Statements of Cash Flows for the Years Ended March 31, 2007, 2006 and 2005	F-6
Notes to Financial Statements	F-7

(a) (2)    Financial Statement Schedules:

None

(a) (3)    Exhibits:

The Exhibits which are filed as part of this Annual Report or which are incorporated by reference are set forth in the Exhibit Index hereto.

37

EXHIBIT INDEX

Exhibit Number		Document Description
3.1		Restated Certificate of Incorporation dated June 30, 1992 and amended September 17, 1999 (filed as Exhibit 3.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
3.2		Certificate of Designation of Series A Junior Participating Preferred Stock dated March 4, 2003 (filed as Exhibit A of Exhibit 1 to Repligen Corporation’s Registration Statement on Form 8-A filed March 4, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
3.3		Amended and Restated By-laws (filed as Exhibit 3.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
4.1		Specimen Stock Certificate filed as Exhibit 4.1 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
4.2	*	The Amended 1992 Repligen Corporation Stock Option Plan, as amended (filed as Exhibit 4.2 to Repligen Corporation’s Form 10-Q for the quarter ended September 30, 2000 and incorporated herein by reference) (SEC File No. 000-14656).
4.3		Rights Agreement, dated as of March 3, 2003, between Repligen Corporation and American Stock Transfer & Trust Company (filed as Exhibit 4.1 to Repligen Corporation’s Form 8-K filed March 4, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
4.5	*	The Amended and Restated 2001 Repligen Corporation Stock Option Plan, adopted by the Stockholders on September 10, 2003 (filed as Appendix B to Repligen Corporation’s Definitive Proxy Statement on Schedule 14A dated July 22, 2003 and incorporated herein by reference)
10.1	*	Consulting Agreement, dated October 1, 1981, between Dr. Paul Schimmel and Repligen Corporation. (filed as Exhibit 10.1 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.2	*	Consulting Agreement, dated November 1, 1981, between Dr. Alexander Rich and Repligen Corporation. (filed as Exhibit 10.2 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.3	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and Walter C. Herlihy (filed as Exhibit 10.3 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.4	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and James R. Rusche (filed as Exhibit 10.4 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.5	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and Daniel P. Witt (filed as Exhibit 10.5 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
#10.6		Patent Purchase Agreement dated as of March 9, 1999 among the Company and Autism Research Institute and Victoria Beck (filed as Exhibit 2.1 to Repligen Corporation’s Form 8-K/A filed June 15, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
#10.7		Manufacturing Transfer Agreement dated as of December 17, 1998 among the Company and Amersham Pharmacia Biotech AB (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 1998 and incorporated herein by reference) (SEC File No. 000-14656).

38

Exhibit Number		Document Description
#10.8		Supply Agreement dated as of May 26, 1999 by and between Repligen Corporation and Amersham Pharmacia Biotech AB (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended June 30, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
#10.9		License Agreement dated as of July 24, 2000 with University of Michigan (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2000 and incorporated herein by reference) (SEC File No. 000-14656).
10.10		Lease Between Repligen Corporation as Tenant and West Seyon LLC as Landlord, 35 Seyon Street, Waltham, MA (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2001 and incorporated herein by reference) (SEC File No. 000-14656).
#10.11		Wellstat/Repligen Settlement Agreement by and among The Regents of The University of California, Robert Naviaux and Repligen Corporation and dated as of November 16, 2004 (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2004 and incorporated herein by reference).
#10.12		Regents/Repligen Settlement Agreement by and between Wellstat Therapeutics Corporation (formerly Pro-Neuron, Inc.) and Repligen Corporation and dated as of November 16, 2004 (as Exhibit 10.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2004 and incorporated herein by reference).
#10.13		Amendment No. 1 to Supply Agreement between Amersham Biosciences and Repligen Corporation dated May 26, 1999, dated February 3, 2005, (SEC File No. 0-14656), (filed as Exhibit 10.13 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2005 and incorporated herein by reference).
10.14	*	The Amended and Restated 2001 Repligen Corporation Stock Option Plan, Form of Incentive Stock Option Plan (filed as Exhibit 10.14 to Repligen Corporation’s Annual Report on form 10-K for the year ended March 31, 2005 and incorporated herein by reference).
10.15	*	The Amended and Restated 2001 Repligen Corporation Stock Plan, Form of Restricted Stock Agreement (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on form 8-K filed on January 9, 2006 and incorporated herein by reference).
10.16	*	Repligen Executive Incentive Compensation Plan (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on form 8-K filed on December 14, 2005 and incorporated herein by reference).
#10.17		Settlement Agreement by and between ChiRhoClin, Inc. and Repligen Corporation, and dated as of May 9, 2005 (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2005 and incorporated herein by reference).
§10.18+		License Agreement by and between The Scripps Research Institute and Repligen Corporation dated April 6, 2007.
23.1+		Consent of Ernst & Young LLP.
24.1+		Power of Attorney (included on signature page).
31.1+		Rule 13a-14(a)/15d-14(a) Certification.
31.2+		Rule 13a-14(a)/15d-14(a) Certification.
32.1+		Certification Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

39

# Confidential treatment obtained as to certain portions.

§ Confidential treatment has been requested for portions of the exhibit and is pending clearance with the Securities and Exchange Commission.

* Management contract or compensatory plan or arrangement

+ Filed herewith.

The exhibits listed above are not contained in the copy of the Annual Report on Form 10-K distributed to stockholders. Upon the request of any stockholder entitled to vote at the 2007 annual meeting, the Registrant will furnish that person without charge a copy of any exhibits listed above. Requests should be addressed to Repligen Corporation, 41 Seyon Street, Waltham, MA 02453.

40

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

REPLIGEN CORPORATION
By:	/S/    WALTER C. HERLIHY
	Walter C. Herlihy Chief Executive Officer and President (Principal executive officer)
Date: June 8, 2007

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below hereby makes, constitutes and appoints Walter C. Herlihy and Daniel W. Muehl with full power to act without the other, his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities to sign any or all amendments to this Form 10-K, and to file the same with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorney-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorney-in-fact and agents of any of them, or any substitute or substitutes, lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

Signature	Title	Date
/S/    ALEXANDER RICH         Alexander Rich, M.D.	Co-Chairman of the Board of Directors	June 8, 2007
/S/    PAUL SCHIMMEL         Paul Schimmel, Ph.D.	Co-Chairman of the Board of Directors	June 8, 2007
/S/    WALTER HERLIHY         Walter C. Herlihy, Ph.D.	President, Chief Executive Officer and Director (Principal executive officer)	June 8, 2007
/S/    DANIEL W. MUEHL         Daniel W. Muehl	Chief Financial Officer (Principal accounting and financial officer)	June 8, 2007
/S/    ROBERT J. HENNESSEY         Robert J. Hennessey	Director	June 8, 2007
/S/    KAREN DAWES         Karen Dawes	Director	June 8, 2007
/S/    THOMAS F. RYAN, JR.         Thomas F. Ryan, Jr.	Director	June 8, 2007

41

EXHIBIT INDEX

Exhibit Number		Document Description
3.1		Restated Certificate of Incorporation dated June 30, 1992 and amended September 17, 1999 (filed as Exhibit 3.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
3.2		Certificate of Designation of Series A Junior Participating Preferred Stock dated March 4, 2003 (filed as Exhibit A of Exhibit 1 to Repligen Corporation’s Registration Statement on Form 8-A filed March 4, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
3.3		Amended and Restated By-laws (filed as Exhibit 3.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
4.1		Specimen Stock Certificate filed as Exhibit 4.1 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
4.2	*	The Amended 1992 Repligen Corporation Stock Option Plan, as amended (filed as Exhibit 4.2 to Repligen Corporation’s Form 10-Q for the quarter ended September 30, 2000 and incorporated herein by reference) (SEC File No. 000-14656).
4.3		Rights Agreement, dated as of March 3, 2003, between Repligen Corporation and American Stock Transfer & Trust Company (filed as Exhibit 4.1 to Repligen Corporation’s Form 8-K filed March 4, 2003 and incorporated herein by reference) (SEC File No. 000-14656).
4.5	*	The Amended and Restated 2001 Repligen Corporation Stock Option Plan, adopted by the Stockholders on September 10, 2003 (filed as Appendix B to Repligen Corporation’s Definitive Proxy Statement on Schedule 14A dated July 22, 2003 and incorporated herein by reference)
10.1	*	Consulting Agreement, dated October 1, 1981, between Dr. Paul Schimmel and Repligen Corporation. (filed as Exhibit 10.1 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.2	*	Consulting Agreement, dated November 1, 1981, between Dr. Alexander Rich and Repligen Corporation. (filed as Exhibit 10.2 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.3	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and Walter C. Herlihy (filed as Exhibit 10.3 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.4	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and James R. Rusche (filed as Exhibit 10.4 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
10.5	*	Employment Agreement, dated March 14, 1996, between Repligen Corporation and Daniel P. Witt (filed as Exhibit 10.5 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2002 and incorporated herein by reference) (SEC File No. 000-14656).
#10.6		Patent Purchase Agreement dated as of March 9, 1999 among the Company and Autism Research Institute and Victoria Beck (filed as Exhibit 2.1 to Repligen Corporation’s Form 8-K/A filed June 15, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
#10.7		Manufacturing Transfer Agreement dated as of December 17, 1998 among the Company and Amersham Pharmacia Biotech AB (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 1998 and incorporated herein by reference) (SEC File No. 000-14656).

42

Exhibit Number	Document Description
#10.8	Supply Agreement dated as of May 26, 1999 by and between Repligen Corporation and Amersham Pharmacia Biotech AB (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended June 30, 1999 and incorporated herein by reference) (SEC File No. 000-14656).
#10.9	License Agreement dated as of July 24, 2000 with University of Michigan (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2000 and incorporated herein by reference) (SEC File No. 000-14656).
10.10	Lease Between Repligen Corporation as Tenant and West Seyon LLC as Landlord, 35 Seyon Street, Waltham, MA (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2001 and incorporated herein by reference) (SEC File No. 000-14656).
#10.11	Wellstat/Repligen Settlement Agreement by and among The Regents of The University of California, Robert Naviaux and Repligen Corporation and dated as of November 16, 2004 (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2004 and incorporated herein by reference).
#10.12	Regents/Repligen Settlement Agreement by and between Wellstat Therapeutics Corporation (formerly Pro-Neuron, Inc.) and Repligen Corporation and dated as of November 16, 2004 (as Exhibit 10.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended December 31, 2004 and incorporated herein by reference).
#10.13	Amendment No. 1 to Supply Agreement between Amersham Biosciences and Repligen Corporation dated May 26, 1999, dated February 3, 2005, (SEC File No. 0-14656), (filed as Exhibit 10.13 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2005 and incorporated herein by reference).
10.14*	The Amended and Restated 2001 Repligen Corporation Stock Option Plan, Form of Incentive Stock Option Plan (filed as Exhibit 10.14 to Repligen Corporation’s Annual Report on form 10-K for the year ended March 31, 2005 and incorporated herein by reference).
10.15*	The Amended and Restated 2001 Repligen Corporation Stock Plan, Form of Restricted Stock Agreement (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on form 8-K filed on January 9, 2006 and incorporated herein by reference).
10.16*	Repligen Executive Incentive Compensation Plan (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on form 8-K filed on December 14, 2005 and incorporated herein by reference).
#10.17	Settlement Agreement by and between ChiRhoClin, Inc. and Repligen Corporation, and dated as of May 9, 2005 (filed as Exhibit 10.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2005 and incorporated herein by reference).
§10.18+	License Agreement by and between The Scripps Research Institute and Repligen Corporation dated April 6, 2007.
23.1+	Consent of Ernst & Young LLP.
24.1+	Power of Attorney (included on signature page).
31.1+	Rule 13a-14(a)/15d-14(a) Certification.
31.2+	Rule 13a-14(a)/15d-14(a) Certification.
32.1+	Certification Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

# Confidential treatment obtained as to certain portions.

§ Confidential treatment has been requested for portions of the exhibit and is pending clearance with the Securities and Exchange Commission.

* Management contract or compensatory plan or arrangement

+ Filed herewith.

43

INDEX TO FINANCIAL STATEMENTS

	Page
Report of Independent Registered Public Accounting Firm	F-2
Balance Sheets as of March 31, 2007 and 2006	F-3
Statements of Operations for the Years Ended March 31, 2007, 2006 and 2005	F-4
Statements of Stockholders’ Equity for the Years Ended March 31, 2007, 2006 and 2005	F-5
Statements of Cash Flows for the Years Ended March 31, 2007, 2006 and 2005	F-6
Notes to Financial Statements	F-7

F-1

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Directors and Stockholders of Repligen Corporation

We have audited the accompanying balance sheets of Repligen Corporation as of March 31, 2007 and 2006, and the related statements of operations, stockholders’ equity, and cash flows for each of the three years in the period ended March 31, 2007. These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

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

In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of Repligen Corporation as of March 31, 2007 and 2006, and the results of its operations, and its cash flows for each of the three years in the period ended March 31, 2007, in conformity with U.S. generally accepted accounting principles.

As discussed in Note 2 to the consolidated financial statements, on April 1, 2006, the Company adopted the provisions of Statement of Financial Accounting Standards No. 123(R), Share-Based Payment.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the effectiveness of Repligen Corporation’s internal control over financial reporting as of March 31, 2007, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated June 6, 2007 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Boston, Massachusetts

June 6, 2007

F-2

REPLIGEN CORPORATION

BALANCE SHEETS

	March 31, 2007			March 31, 2006
Assets
Cash and cash equivalents	$	7,726,505		$	5,428,477
Marketable securities		14,900,840			13,447,600
Accounts receivable, less reserve of $10,000 for 2007 and 2006		1,143,694			593,725
Inventories		1,514,571			1,465,592
Prepaid expenses and other current assets		445,415			575,038
Total current assets		25,731,025			21,510,432
Property, plant and equipment, at cost:
Leasehold improvements		3,212,916			2,475,169
Equipment		2,353,667			1,769,367
Furniture and fixtures		191,356			186,874
		5,757,939			4,431,410
Less-accumulated depreciation and amortization		(2,613,081	)		(2,074,049	)
		3,144,858			2,357,361
Long-term marketable securities		—			4,531,548
Restricted cash		200,000			200,000
Total assets	$	29,075,883		$	28,599,341
Liabilities and stockholder’s equity
Current liabilities:
Accounts payable	$	1,161,504		$	1,066,445
Accrued liabilities		2,175,739			1,869,349
Total current liabilities		3,337,243			2,935,794
Long-term liabilities		200,342			230,518
Total liabilities		3,537,585			3,166,312
Commitments and contingencies
Stockholder’s equity:
Preferred stock, $.01 par value, 5,000,000 shares authorized, no shares issued or outstanding		—			—
Common stock, $.01 par value authorized, 40,000,000 shares outstanding 30,477,635 shares at March 31, 2007 and 30,377,635 shares at March 31, 2006		304,776			303,776
Additional paid-in capital		182,916,856			181,985,274
Deferred compensation		—			(61,950	)
Accumulated deficit		(157,683,334	)		(156,794,071	)
Total stockholders’ equity		25,538,298			25,433,029
Total liabilities and stockholders’ equity	$	29,075,883		$	28,599,341

See accompanying notes

F-3

REPLIGEN CORPORATION

STATEMENTS OF OPERATIONS

	Years ended March 31,
	2007			2006			2005
Revenue:
Product revenue	$	13,073,894		$	12,529,404		$	9,360,309
Other revenue		1,000,345			382,000			—
Total revenue		14,074,239			12,911,404			9,360,309
Operating expenses: (1)
Cost of product revenue		3,614,837			3,550,861			3,887,802
Research and development		5,924,439			5,163,098			5,036,766
Selling, general and administrative		6,360,292			5,417,339			4,597,085
Total operating expenses		15,899,568			14,131,298			13,521,653
Loss from operations	$	(1,825,329	)	$	(1,219,894	)	$	(4,161,344	)
Investment income		947,547			750,156			427,770
Interest expense		(11,481	)		(3,010	)		—
Other income		—			1,169,608			750,000
Net income (loss)	$	(889,263	)	$	696,860		$	(2,983,574	)
Basic and diluted (loss) earnings per share:	$	(0.03	)	$	0.02		$	(0.10	)
Weighted average shares outstanding:
Basic		30,379,350			30,125,041			30,061,812
Diluted		30,379,350			30,690,941			30,061,812
(1) Includes non-cash stock-based compensation as follows:
Cost of product revenue	$	25,655		$	—		$	—
Research and development	$	228,597		$	20,650		$	23,603
Selling, general and administrative	$	582,280		$	—		$	—

See accompanying notes.

F-4

REPLIGEN CORPORATION

STATEMENTS OF STOCKHOLDERS’ EQUITY

AUDITED

	Common Stock					Additional Paid-in Capital			Deferred Compensation			Accumulated Deficit			Stockholders’ Equity
	Number of Shares		Amount
Balance at March 31, 2004	30,036,085		$	300,361		$	181,394,602		$	(23,603	)	$	(154,507,357	)	$	27,164,003
Exercise of stock options	58,350			583			29,918			—			—			30,501
Compensation expense related to issuance of stock options	—			—			55,125			—			—			55,125
Amortization of deferred compensation	—			—			—			23,603			—			23,603
Net loss	—			—			—			—			(2,983,574	)		(2,983,574	)
Balance at March 31, 2005	30,094,435		$	300,944		$	181,479,645		$	—		$	(157,490,931	)	$	24,289,658
Issuance of common stock for services	25,000			250			85,500									85,750
Deferred compensation related to employee stock options	20,000			200			82,600			(82,600	)					200
Amortization of deferred compensation										20,650						20,650
Exercise of stock options	238,200			2,382			337,529			—			—			339,911
Net income	—			—			—			—			696,860			696,860
Balance at March 31, 2006	30,377,635		$	303,776		$	181,985,274		$	(61,950	)	$	(156,794,071	)	$	25,433,029
Reclassification of deferred compensation							(61,950	)		61,950						—
Share-based compensation expense							836,532									836,532
Repurchase and retirement of treasury stock	(10,000	)		(100	)		100									—
Exercise of stock options	110,000			1,100			156,900									158,000
Net loss													(889,263	)		(889,263	)
Balance, March 31, 2007	30,477,635		$	304,776		$	182,916,856		$	—		$	(157,683,334	)	$	25,538,298

See accompanying notes.

F-5

REPLIGEN CORPORATION

STATEMENTS OF CASH FLOWS

AUDITED

	Years ended March 31,
	2007			2006			2005
Cash flows from operating activities:
Net (loss) income:	$	(889,263	)	$	696,860		$	(2,983,574	)
Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities
Issuance of common stock for service		—			85,750			—
Depreciation and amortization		539,032			398,434			756,258
Stock-based compensation expense		836,532			20,650			23,603
Loss on disposal of assets		—			18,369			(20,000	)
Bad debt reserve		—			(5,000	)		—
Changes in assets and liabilities:
Accounts receivable		(549,969	)		175,507			228,017
Inventories		(48,979	)		(832,278	)		246,067
Prepaid expenses and other current assets		106,827			133,906			(252,633	)
Accounts payable		95,059			49,487			302,667
Accrued liabilities		346,419			(327,805	)		577,203
Long-term liabilities		(30,176	)		1,504			9,787
Net cash (used in) provided by operating activities		405,482			415,385			(1,112,605	)
Cash flows from investing activities:
Purchases of marketable securities		(13,973,896	)		(11,383,595	)		(16,904,423	)
Redemptions of marketable securities		17,075,000			13,583,000			17,301,991
Purchases of property, plant and equipment		(1,326,529	)		(735,495	)		(52,658	)
Net cash provided by investing activities		1,774,575			1,463,910			344,910
Cash flows from financing activities:
Exercise of stock options		158,000			340,111			30,501
Principal payments under capital lease obligation		(40,029	)		(7,609	)		(4,802	)
Net cash provided by financing activities		117,971			332,502			25,699
Net increase (decrease) in cash and cash equivalents		2,298,028			2,211,796			(741,996	)
Cash and cash equivalents, beginning of period	$	5,428,477		$	3,216,681		$	3,958,677
Cash and cash equivalents, end of period	$	7,726,505		$	5,428,477		$	3,216,681
Supplemental disclosure of noncash activities:
Purchase of Capital Lease Equipment	$	—		$	133,261		$	33,605
Reclassification of Deferred Compensation	$	61,950		$	—		$	—
Recording of Deferred Compensation	$	—		$	82,600		$	—
Disposal of fully depreciated equipment	$	—		$	109,339		$	283,505

See accompanying notes

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REPLIGEN CORPORATION

NOTES TO FINANCIAL STATEMENTS

1. Organization and Nature of Business

Repligen Corporation (“Repligen” or the “Company”) is a biopharmaceutical company focused on the development of novel therapeutics for the treatment of diseases of the central nervous system. A number of drug development programs are currently being conducted to evaluate the Company’s naturally occurring drug candidates in diseases such as bipolar disorder and neurodegeneration. In addition, Repligen sells two commercial products, Protein A for monoclonal antibody purification and SecreFlo^® for assessment of pancreatic disorders.

The Company’s business strategy is to deploy the profits from its commercial products and any revenue that it may receive from its patents to enable the Company to invest in the development of product candidates in the treatment area of neuropsychiatric diseases.

The Company is subject to a number of risks typically associated with companies in the biotechnology industry. Principally those risks are associated with the Company’s dependence on collaborative arrangements, development by the Company or its competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with the U.S. Food and Drug Administration and other governmental regulations and approval requirements, as well as the ability to grow the Company’s business and obtain adequate funding to finance this growth.

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Revenue Recognition

The Company applies Staff Accounting Bulletin No. 104, “Revenue Recognition” (“SAB No. 104”) to its revenue arrangements.

The Company generates product revenues from the sale of Protein A products to customers in the pharmaceutical and process chromatography industries and from the sale of SecreFlo^® to hospital-based gastroenterologists. In accordance with SAB No. 104, the Company recognizes revenue related to product sales upon delivery of the product to the customer as long as there is persuasive evidence of an arrangement, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Determination of whether these criteria have been met are based on management’s judgments primarily regarding the fixed nature of the fee charged for product delivered, and the collectibility of those fees. The Company has a few longstanding customers who comprise the majority of product revenue and have excellent payment history. The Company has had no significant write-offs of uncollectible invoices in the periods presented. Should changes in conditions cause management to determine that these criteria are not met for certain future transactions, revenue recognized for any reporting period could be adversely affected.

At the time of sale, the Company also evaluates the need to accrue for warranty and sales returns. The supply agreements the Company has with its customers and related purchase orders identify the terms and conditions of each sale and the price of the goods ordered. Due to the nature of the sales arrangements, inventory

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produced for sale is tested for quality specifications prior to shipment. Since the product is manufactured to order and in compliance with required specifications prior to shipment, the likelihood of sales return, warranty or other issues is largely diminished. Sales returns and warranty issues are infrequent and have had nominal impact on the Company’s financial statements historically. Should changes in conditions cause management to determine that warranty, returns or other sale-related reserves are necessary for certain future transactions, revenue recognized for any reporting period could be adversely affected.

During the fiscal year ended March 31, 2007, the Company recognized $825,000 of revenue from a sponsored research and development project under an agreement with the Stanley Medical Research Institute (SMRI). Research revenue is recognized on a cost plus fixed-fee basis when the expense has been incurred and services have been performed. Determination of which costs incurred qualify for reimbursement under the terms of the contractual agreement and the timing of when such costs were incurred involves the judgment of management. The Company believes its calculations are based upon the agreed-upon terms as stated in the arrangement. However, should the estimated calculations change or be challenged by SMRI, research revenue may be adjusted in subsequent periods. The calculations have not historically changed or been challenged and the Company does not anticipate any subsequent change in its revenue related to this sponsored research and development project.

Additionally, during fiscal year 2007, the Company earned and recognized approximately $175,000 in royalty revenue from ChiRhoClin, Inc. Revenues earned from ChiRhoClin royalties are recorded in the periods when they are earned based on royalty reports sent by ChiRhoClin to the Company.

There have been no material changes to the Company’s initial estimates related to revenue recognition in any periods presented in the accompanying financial statements.

Risks and Uncertainties

The Company evaluates its operations periodically to determine if any risks and uncertainties exist that could impact its operations in the near term. The Company does not believe that there are any significant risks which have not already been disclosed in the financial statements. However, the Company does rely on a single supplier for SecreFlo^® materials. Although alternate sources of supply exist for these items, loss of certain suppliers could temporarily disrupt operations. The Company attempts to mitigate these risks by working closely with key suppliers, identifying alternate sources and developing contingency plans.

Comprehensive Income

The Company applies Statement of Financial Accounting Standards (SFAS) No. 130, “Reporting Comprehensive Income.” SFAS No. 130 requires disclosure of all components of comprehensive income on an annual and interim basis. Comprehensive income is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from nonowner sources. The Company’s comprehensive income (loss) is equal to its reported net income (loss) for all periods presented.

Cash Equivalents & Marketable Securities

The Company applies SFAS No. 115, “Accounting for Certain Investments in Debt and Equity Securities.” At March 31, 2007, the majority of the Company’s cash equivalents and marketable securities are classified as held-to-maturity investments as the Company has the positive intent and ability to hold to maturity. As a result, these investments are recorded at amortized cost. Marketable securities are investments with original maturities of greater than 90 days. Long-term marketable securities are investment grade securities with maturities of greater than one year.

At March 31, 2007, marketable securities also include investment grade auction rate securities, which provide higher yields than money market and other cash equivalent investments. Auction rate securities have

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long-term underlying maturities, but have interest rates that are reset every 90 days or less, at which time the securities can typically be purchased or sold, which creates a highly liquid market for these securities. The Company does not intend to hold these securities to maturity, but rather to use the securities to provide liquidity as necessary. Auction rate securities are classified as available-for-sale and reported at fair value. Due to the reset feature and their carrying value equaling their fair value, there are no unrealized gains or losses from these short-term investments.

Cash equivalents and marketable securities consist of the following at March 31, 2007 and 2006:

	As of March 31,				Unrealized Holding Loss Year Ended March 31,
	2007		2006		2007			2006
Cash and cash equivalents	$	7,726,505	$	5,428,477	$	—		$	—
Marketable securities:
U.S. Government and agency securities		3,460,665		8,048,129		(8,273	)		(64,571	)
Auction Rate Securities		475,000		1,075,000		—			—
Corporate and other debt securities		10,965,175		4,324,471		(9,877	)		—
	$	14,900,840	$	13,447,600	$	(18,150	)	$	(64,571	)
Long-term marketable securities:
U.S. Government and agency securities		—		1,900,000		—			(25,328	)
Corporate and other debt securities		—		2,631,548		—			(38,915	)
	$	—	$	4,531,548	$	—		$	(64,243	)

Restricted cash of $200,000 is related to the Company’s facility lease obligation.

* Average of remaining maturity of approximately 5 months at March 31, 2007. Assumes auction rate maturity set at date of next auction

Fair Value of Financial Instruments

The carrying amounts of the Company’s financial instruments which represent cash, marketable securities, and accounts receivable generally approximate fair value due to the short-term nature of these instruments.

Concentrations of Credit Risk and Significant Customers

Financial instruments that subject the Company to significant concentrations of credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. The Company’s cash equivalents and marketable securities are invested in financial instruments with high credit ratings and by policy limits the amount of its credit exposure to any one issue, issuer, (with the exception of U.S. treasury obligations) and type of instrument. At March 31, 2007, the Company has no items such as those associated with foreign exchange contracts, options contracts or other foreign hedging arrangements.

Concentration of credit risk with respect to accounts receivable is limited to customers to whom the Company makes significant sales. The Company maintains reserves for the potential write-off of accounts receivable. To date, the Company has not written off any significant accounts. To control credit risk, the Company performs regular credit evaluations of its customers’ financial condition.

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Revenue from significant customers as a percentage of the Company’s total revenue is as follows:

	Years Ended March 31,
	2007		2006		2005
Customer A	49	%	49	%	54	%
Customer B	*	%	*	%	10	%
Customer C	23	%	26	%	13	%

* Represents less than 10% of total revenue for the period

Significant accounts receivable balances as a percentage of the Company’s total trade accounts receivable balances are as follows:

	As of March 31,
	2007		2006
Customer A	15	%	25	%
Customer B	*	%	13	%
Customer C	*	%	11	%
Customer D	47	%	25	%

* Did not represent 10% of total accounts receivable at March 31, 2007

Inventories

Inventories relate to the Company’s Protein A business. The Company values inventory at cost or, if lower, fair market value. Repligen determines cost using the first-in, first-out method. The Company reviews its inventories at least quarterly and records a provision for excess and obsolete inventory based on its estimates of expected sales volume, production capacity and expiration dates of raw materials, work-in process and finished goods. Expected sales volumes are determined based on supply forecasts provided by key customers for the next three to twelve months. The Company writes down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value, and inventory in excess of expected requirements to cost of goods sold. Manufacturing of Protein A finished goods is done to order and tested for quality specifications prior to shipment.

A change in the estimated timing or amount of demand for our products could result in additional provisions for excess inventory quantities on hand. Any significant unanticipated changes in demand or unexpected quality failures could have a significant impact on the value of inventory and reported operating results. During all periods presented in the accompanying financial statements, there has been no material adjustments related to a revised estimate of inventory valuations.

Inventories are stated at the lower of cost (first-in, first-out) or market. Work-in-process and finished goods inventories consist of material, labor, outside processing costs and manufacturing overhead. Inventories at March 31, 2007 and 2006 consist of the following:

	As of March 31,
	2007		2006
Raw materials	$	733,112	$	600,948
Work-in process		616,519		596,386
Finished goods		164,940		268,258
Total	$	1,514,571	$	1,465,592

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Depreciation and Amortization

Depreciation and amortization are calculated using the straight-line method over the estimated useful life of the asset as follows:

Description	Estimated Useful Life
Leasehold improvements	Shorter of term of the lease or estimated useful life
Equipment	3-5 years
Furniture and fixtures	5 years

The Company recorded depreciation and amortization of property, plant and equipment expense of $539,032, $398,434 and $363,738 in 2007, 2006 and 2005, respectively. Depreciation of assets under capital leases is included in depreciation and amortization. The amount of depreciation recorded for assets under capital lease agreements for fiscal years 2007, 2006, and 2005 was $41,850, $16,268 and $4,721, respectively.

Earnings Per Share

The Company applies the provisions of Statement of Financial Accounting Standard (“SFAS”) No. 128, “Presenting Earnings Per Share.” Basic earnings per share for the periods ended March 31, 2007, 2006 and 2005 were computed on the basis of the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share is computed on the basis of the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period using the treasury stock method in accordance with SFAS No. 128. Dilutive potential common shares include outstanding stock options.

Basic and diluted weighted average shares outstanding were as follows:

	Twelve Months Ended March 31,
	2007	2006	2005
Weighted average common shares outstanding	30,379,350	30,125,041	30,061,812
Dilutive common stock options	—	565,900	—
Weighted average common shares outstanding, assuming dilution	30,379,350	30,690,941	30,061,812

Diluted weighted average shares outstanding for 2007 does not include the potential common shares for stock options because to do so would be antidilutive. Accordingly, basic and diluted net loss per share is the same. The number of potential common shares excluded from the calculation of diluted earnings per share during the year ended March 31, 2007 was 2,292,750.

For the year ended March 31, 2006, options to purchase 955,400 shares were excluded from the calculation of diluted earnings per share because the exercise prices of the stock options were greater than or equal to the average price of the common shares.

Diluted weighted average shares outstanding for 2005 do not include the potential common shares from warrants and stock options because to do so would have been antidilutive. Accordingly, basic and diluted net loss per share is the same. The number of potential common shares excluded from the calculation of diluted earnings per share during the year ended March 31, 2005 was 2,166,900.

Segment Reporting

The Company applies SFAS No. 131, “Disclosures about Segments of an Enterprise and Related Information.” SFAS No. 131 establishes standards for reporting information regarding operating segments in annual financial statements and requires selected information for those segments to be presented in interim

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financial reports issued to stockholders. SFAS No. 131 also establishes standards for related disclosures about products and services and geographic areas. The chief operating decision maker, or decision-making group, in making decisions how to allocate resources and assess performance, identifies operating segments as components of an enterprise about which separate discrete financial information is available for evaluation. To date, the Company has viewed its operations and manages its business as one operating segment. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s principal operating segment.

The following table represents the Company’s revenue by geographic area (based on the location of the customer):

	Year Ended March 31,
	2007		2006		2005
Europe	52	%	51	%	56	%
United States	47	%	48	%	43	%
Other	1	%	1	%	1	%
Total	100	%	100	%	100	%

The following table represents the Company’s product revenue by product type:

	Year ended March 31,
	2007		2006		2005
Protein A	$	11,127	$	10,540	$	7,134
SecreFlo®		1,947		1,989		2,189
Other product revenue		—		—		37
Product revenue	$	13,074	$	12,529	$	9,360

As of March 31, 2007 and 2006 all of the Company’s assets are located in the United States.

Recent Accounting Pronouncements

Accounting for Uncertainty in Income Taxes

In June 2006, the Financial Accounting Standards Board (FASB) issued FASB Interpretation No. 48, “Accounting for Uncertainty in Income Taxes—an Interpretation of FASB Statement No. 109” (the “Interpretation”). The Interpretation clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” The Interpretation prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This Interpretation also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The Interpretation is effective for fiscal years beginning after December 15, 2006. The Company has not yet completed its evaluation of the Interpretation, but does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

Fair Value Measurements

In September 2006, the FASB issued FASB Statement No. 157 “Fair Value Measurements” (SFAS No. 157). SFAS No. 157 establishes a common definition for fair value, creates a framework for measuring fair value, and expands disclosure requirements about such fair value measurements. SFAS No. 157 is effective for our first quarter of 2008. Management does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

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Fair Value Option for Financial Assets and Financial Liabilities

In February 2007, the FASB issued FASB Statement No. 159, “The Fair Value Option for Financial Assets and Financial Liabilities” (SFAS No. 159). SFAS No. 159 provides companies with an option to report selected financial assets and liabilities at fair value. The objective of SFAS No. 159 is to reduce both complexity in accounting for financial instruments and the volatility in earnings caused by measuring related assets and liabilities differently. Generally accepted accounting principles have required different measurement attributes for different assets and liabilities that can create artificial volatility in earnings. FASB has indicated it believes that SFAS No. 159 helps to mitigate this type of accounting- induced volatility by enabling companies to report related assets and liabilities at fair value, which would likely reduce the need for companies to comply with detailed rules for hedge accounting. SFAS No. 159 also establishes presentation and disclosure requirements designed to facilitate comparisons between companies that choose different measurement attributes for similar types of assets and liabilities. For example, SFAS No. 159 requires companies to provide additional information that will help investors and other users of financial statements to more easily understand the effect of the company’s choice to use fair value on its earnings. It also requires entities to display the fair value of those assets and liabilities for which the company has chosen to use fair value on the face of the balance sheet. SFAS No. 159 does not eliminate disclosure requirements included in other accounting standards, including requirements for disclosures about fair value measurements included in FASB Statement No. 157, “Fair Value Measurements” (SFAS No. 157), and FASB Statement No. 107, “Disclosures about Fair Value of Financial Instruments” (SFAS No. 107). SFAS No. 159 is effective as of the beginning of a company’s first fiscal year beginning after November 15, 2007. Early adoption is permitted as of the beginning of the previous fiscal year provided that the company makes that choice in the first 120 days of that fiscal year and also elects to apply the provisions of SFAS No. 157. The Company has not yet completed its evaluation of the Interpretation, but does not currently believe that adoption will have a material impact on its results of operations, financial position or cash flows.

Stock Based Compensation

In December 2004, the Financial Accounting Standards Board (“FASB”) issued SFAS No. 123R, “Share-Based Payment—An Amendment of FASB Statements No. 123 and 95,” (“SFAS No. 123R”), which requires all companies to measure compensation cost for all share-based payments, including employee stock options, at fair value. Generally, the approach in SFAS No. 123R is similar to the approach described in SFAS No. 123, “Accounting for Stock-Based Compensation,” (“SFAS No. 123”). However, SFAS No. 123R requires all share-based payments to employees, including grants of employee stock options, to be recognized in the financial statements based on their fair value over the requisite service period. Pro forma disclosure is no longer an alternative. In March 2005, the SEC issued Staff Accounting Bulletin (“SAB”) No. 107 (“SAB No. 107”), which expressed the views of the SEC regarding the interaction between SFAS No. 123(R) and certain rules and regulations of the SEC. SAB No. 107 provides guidance related to the valuation of share-based payment arrangements for public companies, including assumptions such as expected volatility and expected term.

Prior to the adoption of SFAS No. 123(R), the Company applied SFAS No. 123, Accounting for Stock-Based Compensation , amended by SFAS No. 148, Accounting for Stock-based Compensation—Transition and Disclosure , which allowed companies to apply the existing accounting rules under APB Opinion No. 25. Pursuant to APB Opinion No. 25, the Company accounted for its stock-based awards to employees using the intrinsic-value method, under which compensation expense was measured on the date of grant as the difference between the fair value of the Company’s common stock and the option exercise price multiplied by the number of options granted. Generally, the Company granted stock options with exercise prices equal to the estimated fair value of its common stock; however, to the extent that the fair value of the common stock exceeded the exercise price of stock options granted to employees on the date of grant, the Company recorded deferred compensation and amortized the expense over the vesting schedule of the options, generally four years. During the years ended March 31, 2006 and 2005, in accordance with APB Opinion No. 25, the Company recorded deferred stock-based compensation resulting from the grant of employee stock options with an exercise price less than the fair value of common stock. As of March 31, 2006, the Company had $61,950 of deferred stock-based compensation

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remaining to be amortized. Upon the adoption of SFAS No. 123(R) on April 1, 2006, the deferred stock-based compensation balance was netted against additional paid-in capital on the consolidated balance sheet and statement of stockholders equity.

The following table illustrates the effect on net income and net income per share if the Company had applied the fair value recognition provisions of SFAS No. 123 to options granted under the Plans for the fiscal years ended March 31, 2005 and 2006. Since stock-based compensation expense for the fiscal years ended March 31, 2007 was calculated under the provisions of SFAS No. 123R, there is no disclosure of pro forma net income and net income per share for that period. For purposes of the pro forma disclosure for the fiscal years ended March 31, 2005 and 2006 set forth in the table below, the value of the options is estimated using a Black-Scholes option pricing model and amortized on a straight-line basis to expense over the options’ vesting periods.

	Year ended
	March 31, 2006			March 31, 2005
Net income (loss) as reported	$	696,860		$	(2,983,574	)
Add: Stock-based employee compensation cost included in reported net income (loss)		20,650			8,042
Deduct: Stock-based employee conpensation cost that would have been included in the determination of net loss as reported if the fair value method had been applied to all awards		(745,043	)		(980,240	)
Pro forma net (loss)	$	(27,533	)	$	(3,955,772	)
Basic and diluted net income (loss) per common share, as reported	$	0.02		$	(0.10	)
Basic and diluted net income (loss) per common share, as pro forma	$	—		$	(0.13	)

Effective April 1, 2006, the Company adopted the fair value recognition provisions of SFAS No. 123(R), using the modified prospective transition method. Under this transition method, compensation cost recognized in the statement of operations for the fiscal year ended March 31, 2007 includes: (a) compensation cost for all share-based payments granted prior to, but not yet vested as of April 1, 2006, based on the grant-date fair value estimated in accordance with the original provisions of SFAS No. 123 adjusted for estimated forfeitures and (b) compensation cost for all share-based payments granted, modified or settled subsequent to April 1, 2006, based on the grant-date fair value estimated in accordance with the provisions of SFAS No. 123(R). In accordance with the modified prospective transition method, results for prior periods have not been restated.

For the fiscal year ended March 31, 2007, the Company recorded stock-based compensation expense of approximately $837,000 for stock options granted under the Amended and Restated 2001 Repligen Corporation Stock Plan. Basic and diluted earnings per share amounts for the fiscal year ended March 31, 2007 were decreased by $0.03 as a result of the adoption of SFAS No. 123(R).

The Company currently has the following stock-based employee compensation plans which are subject to the provisions of SFAS No. 123(R): the 1992 Repligen Corporation Stock Option Plan, as amended, and the Amended and Restated 2001 Repligen Corporation Stock Plan (collectively, the “Plans”). The 1992 Repligen Corporation Stock Option Plan expired on September 14, 2001, though this had no impact on outstanding option grants. Options granted prior to the date of termination remain outstanding and may be exercised in accordance with their terms.

The Plans allow for the granting of incentive and nonqualified options and restricted stock and other equity awards to purchase shares of Common Stock. Historically, incentive options granted to employees under the Plans generally vested over a four to five-year period, with 20%-25% vesting on the first anniversary of the date of grant and the remainder vesting in equal yearly installments thereafter. Nonqualified options issued to non-employee directors and consultants under the Plans generally vest over one year. Options granted under the

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Plans have a maximum term of ten years from the date of grant and generally, the exercise price of the stock options equals the fair market value of the Company’s Common Stock on the date of grant. At March 31, 2007, options to purchase 1,424,250 shares were outstanding under the Amended and Restated 2001 Repligen Corporation Plan and 868,500 were outstanding under the 1992 Repligen Corporation Stock Option Plan. At March 31, 2007, 420,109 shares were available for future grant under the Amended and Restated 2001 Repligen Corporation Stock Plan.

The Company uses the Black-Scholes option pricing model to calculate the fair value on the grant date of stock-based compensation for stock options granted under the Plans. The fair value of stock options granted during the fiscal years ended March 31, 2007 and March 31, 2006 were calculated using the following estimated weighted- average assumptions:

	Year ended
	March 31, 2007	March 31, 2006	March 31, 2005
Expected term (years)	6.5	7	7
Volatility	77.24%-91.86%	90.79%-94.41%	94.17%-95.38%
Risk-free interest rate	4.44%-5.07%	3.83%-4.58%	3.76%-4.29%
Expected dividend yield	—	—	—

Expected term—The expected term of options granted represents the period of time for which the options are expected to be outstanding and is derived from the Company’s historical stock option exercise experience and option expiration data. For option grants made subsequent to the adoption of SFAS No. 123R, the expected life of stock options granted is based on the simplified method allowable under SAB No. 107. Accordingly, the expected term is presumed to be the midpoint between the vesting date and the end of the contractual term. In addition, for purposes of estimating the expected term, the Company has aggregated all individual option awards into one group as the Company does not expect substantial differences in exercise behavior among its employees.

Expected volatility— The expected volatility is a measure of the amount by which the Company’s stock price is expected to fluctuate during the expected term of options granted. The Company determines the expected volatility solely based upon the historical volatility of the Company’s Common Stock over a period commensurate with the option’s expected term. The Company does not believe that the future volatility of its Common Stock over an option’s expected term is likely to differ significantly from the past.

Risk-free interest rate— The risk-free interest rate is the implied yield available on U.S. Treasury zero-coupon issues with a remaining term equal to the option’s expected term on the grant date.

Expected dividend yield—The Company has never declared or paid any cash dividends on any of its capital stock and does not expect to do so in the foreseeable future. Accordingly, the Company uses an expected dividend yield of zero to calculate the grant-date fair value of a stock option.

The Company recognizes compensation expense on a straight-line basis over the requisite service period based upon options that are ultimately expected to vest, and accordingly, such compensation expense has been adjusted by an amount of estimated forfeitures. Forfeitures represent only the unvested portion of a surrendered option. SFAS No. 123(R) requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Prior to the adoption of SFAS No. 123(R), the Company accounted for forfeitures upon occurrence as permitted under SFAS No. 123. Based on an analysis of historical data, the Company has calculated an 8% annual forfeiture rate for non-director level employees, a 3% annual forfeiture rate for director- level employees, and a 0% forfeiture rate for non-employee members of the Board of Directors, which it believes is a reasonable assumption to estimate forfeitures. However, the estimation of forfeitures requires significant judgment, and to the extent actual results or updated estimates differ from the Company’s current estimates, such amounts will be recorded as a cumulative adjustment in the period estimates are revised.

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Information regarding option activity for the year ended March 31, 2007 under the Plans is summarized below:

	Options Outstanding (in thousands)		Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousand)
Options outstanding at March 31, 2004	2,051		$	3.01
Granted	340			2.56
Exercised	(58	)		0.52
Forfeited/Cancelled	(191	)		3.07
Options outstanding at March 31, 2005	2,142			3.00
Granted	629			3.04
Exercised	(238	)		1.36
Forfeited/Cancelled	(130	)		3.13
Options outstanding at March 31, 2006	2,403			3.17
Granted	210			2.98
Exercised	(110	)		1.43
Forfeited/Cancelled	(210	)		3.03
Options outstanding at March 31, 2007	2,293		$	3.25	5.39	$	1,485
Options exercisable at March 31, 2007	1,564		$	3.28	4.13	$	1,209
Vested and expected to vest at March 31, 2007 (1)	2,235		$	2.63	5.29	$	1,468

(1) This represents the number of vested options as of March 31, 2007 plus the number of unvested options expected to vest as of March 31, 2007 based on the unvested outstanding options at March 31, 2007 adjusted for the estimated forfeiture rate of 8% for awards granted to non-director level employees and 3% for awards granted to director level employees.

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between the closing price of the Common Stock on March 30, 2007 of $3.16 and the exercise price of each in-the-money option) that would have been received by the option holders had all option holders exercised their options on March 30, 2007.

The weighted average grant date fair value of options granted during the fiscal year ended March 31, 2007 was $2.31. The total fair value of stock options that vested during the fiscal year ended March 31, 2007 and 2006 was approximately $869,000 and $871,000, respectively. The total intrinsic value of options exercised during the years ended March 31, 2007 2006 and 2005 was $189,800, $852,152, and $95,563, respectively, determined as of the date of exercise. The Company received $158,000, $340,111 and $30,501 from stock option exercises during the years ended March 31, 2007, 2006 and 2005, respectively.

As of March 31, 2007, there was $1,275,000 of total unrecognized compensation cost related to unvested share-based awards. This cost is expected to be recognized over a weighted average remaining requisite service period of 2.86 years. The Company expects approximately 671,000 of unvested outstanding options to vest over the next five years.

F-16

The range of exercise prices for options outstanding and exercisable as of March 31, 2007 are as follows:

Outstanding as of March 31, 2007					Exercisable as of March 31, 2007
Range of Exercise Prices	Number of Shares	Weighted Average Remaining Contractual Life in years	Weighted Average Exercise price		Number of Shares	Weighted Average Exercise price
$0.00 - $1.24	17,000	2.99	$	1.01	17,000	$	1.01
$1.25 - $2.49	858,000	3.72		1.64	687,900		1.59
$2.50 - $3.73	868,250	6.64		3.04	480,200		3.03
$3.74 - $4.98	134,500	8.54		4.19	39,700		4.23
$4.99 - $6.22	196,000	5.98		5.53	119,999		5.54
$6.23 - $7.47	5,000	3.47		7.19	5,000		7.19
$7.48 - $8.56	214,000	4.69		7.93	214,000		7.93
	2,292,750	5.39	$	3.25	1,563,799	$	3.28

3. Income Taxes

The Company accounts for income taxes under SFAS No. 109, “Accounting for Income Taxes.” The Company did not record a tax provision for the years ended March 31, 2007, 2006 and 2005 as the Company did not generate taxable income.

At March 31, 2007, the Company had net operating loss carryforwards for income tax purposes of approximately $100,130,000. The Company also had available tax credit carryforwards of approximately $5,270,000 at March 31, 2007 to reduce future federal income taxes, if any. Federal and state net operating losses of approximately $9,004,000, $7,689,000 and $7,390,000 expired in fiscal 2007, 2006 and 2005, respectively. The net operating loss and tax credit carryforwards will continue to expire at various dates. Net operating loss carryforwards and available tax credits are subject to review and possible adjustment by the Internal Revenue Service and may be limited in the event of certain changes in the ownership interest of significant stockholders.

Deferred tax assets consist of the following:

	As of March 31,
	2007			2006
Temporary differences	$	6,580,000		$	7,420,000
Operating loss carryforwards		40,060,000			42,520,000
Tax credit carryforwards		5,270,000			5,590,000
		51,910,000			55,530,000
Valuation allowance		(51,910,000	)		(55,530,000	)
	$	—		$	—

A full valuation allowance has been provided, as it is uncertain if the Company will realize its deferred tax assets.

A reconciliation of the federal statutory rate to the effective income tax rate from operations for fiscal years ended March 31, 2007, 2006 and 2005 is as follows:

	Years Ended March 31,									Years Ended March 31,
	2007			2006			2005			2007		2006		2005
Tax at U.S. statutory rate	$	(302,350	)	$	(237,000	)	$	(1,014,000	)	34.00	%	34.00	%	34.00	%
State taxes, net of federal benefit		—			—			—		0.00	%	0.00	%	0.00	%
Permanent differences, net of federal benefit		152,887			(5,000	)		6,000		(17.00	)%	0.08	%	(0.20	)%
Change in valuation allowance		(149,463	)		(242,000	)		1,008,000		(17.00	)%	(34.08	)%	(33.80	)%
Income tax expense	$	—		$	—		$	—		0.00	%	0.00	%	0.00	%

F-17

4. Stockholders’ Equity

Common Stock and Warrants

At March 31, 2007, the Company has reserved 2,712,859 shares of common stock for incentive and nonqualified stock option plans.

Shareholder Rights Plan

In March 2003, the Company adopted a Shareholder Rights Agreement (the “Rights Agreement”). Under the Rights Agreement, the Company distributed certain rights to acquire shares of the Company’s Series A junior participating preferred stock (the “Rights”) as a dividend for each share of common stock held of record as of March 17, 2003. Each share of common stock issued after the March 17, 2003 record date has an attached Right. Under certain conditions involving an acquisition by any person or group of 15% or more of the common stock, each Right permits the holder (other than the 15% holder) to purchase common stock having a value equal to twice the exercise price of the Right, upon payment of the exercise price of the Right. In addition, in the event of certain business combinations after an acquisition by a person or group of 15% or more of the common stock (20% in the case of a certain stockholder), each Right entitles the holder (other than the 15% holder) to receive, upon payment of the exercise price, common stock having a value equal to twice the exercise price of the Right. The Rights have no voting privileges and, unless and until they become exercisable, are attached to, and automatically trade with, the Company’s common stock. The Rights will terminate upon the earlier of the date of their redemption or March 2013.

5. Commitments and Contingencies

Lease Commitments

In 2001, the Company entered into a ten-year lease agreement for its corporate headquarters in Waltham, Massachusetts. In connection with this lease agreement, the Company issued a letter of credit in the amount of $200,000 to its landlord. The letter of credit is collateralized by a certificate of deposit held by the bank that issued the letter of credit. The certificate of deposit is classified as restricted cash in the accompanying balance sheet as of March 31, 2007 and 2006. The Company signed a lease in April 2007 for 2,500 square feet of space in Waltham, Massachusetts for off-site storage of materials. The lease expires in March 2012.

In fiscal 2006, the Company entered into a capital lease agreement to provide the Company with manufacturing equipment. Repligen received approximately $171,000 in equipment financing over a five year period. In fiscal 2005, the Company entered into two capital lease agreements to provide the Company with two pieces of office equipment. Repligen received approximately $33,000 in equipment financing. The lease terms are three and five years beginning in June and October of 2004, respectively. Capital lease obligations are recorded in accrued liabilities and long-term liabilities in the Company’s balance sheets.

Obligations under non-cancelable operating leases and capital equipment leases, including the facility lease discussed above, as of March 31, 2007 are approximately as follows:

Years Ending March 31,	Operating Lease		Capital Lease
2008	$	449,000		48,870
2009		455,000		48,870
2010		473,000		45,209
2011		473,000		—
Thereafter		361,000		—
Minimum lease payments	$	2,211,000	$	142,949
Less amount representing interest				(17,648	)
Present value of future lease payment				125,301
Less current portion				(48,870	)
Noncurrent obligation under capital leases			$	76,431

F-18

Rent expense charged to operations under operating leases was approximately $389,000 for each of the years ended March 31, 2007, 2006 and 2005. As of March 31, 2007 and 2006 the Company had deferred rent liability of $119,000 and $120,000, respectively related to the Waltham facility.

Licensing and Research Agreements

The Company licenses certain technologies that are, or may be, incorporated into its technology under several agreements and also has entered into several clinical research agreements which require the Company to fund certain research projects. Generally, the license agreements require the Company to pay annual maintenance fees and royalties on product sales once a product has been established using the technologies. The Company has recorded research and development expense associated with license agreements of $87,000, $114,000 and $55,000, for the years ended March 31, 2007, 2006 and 2005, respectively.

Supply Agreements

The Company has entered into an agreement with a manufacturer for certain components of its Protein A product. The Company has remaining purchase obligations of approximately $298,000 associated with this agreement for the year ended March 31, 2008. The Company relies on a sole manufacturer for its SecreFlo^® product. This reliance exposes it to a number of risks, including reduced control over manufacturing capacity, delivery times, inadequate inventory levels which could lead to product shortage or charges for excess or obsolete inventory.

6. Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following:

	As of March 31,
	2007		2006
Prepaid insurance	$	124,376	$	115,591
Equipment and services		71,656		221,565
Interest receivable		167,483		188,751
Clinical and research expenses.		47,636		32,829
Other		34,264		16,302
	$	445,415	$	575,038

7. Accrued Liabilities

The Company prepares its financial statements in accordance with accounting principles generally accepted in the United States. These principles require that the Company estimate accrued liabilities. This process involves identifying services, which have been performed on the company’s behalf, and estimating the level of service performed and the associated cost incurred for such service as of each balance sheet date. Examples of estimated accrued expenses include: 1) Fees paid to contract manufacturers in conjunction with the production of clinical materials. These expenses are normally determined through a contract or purchase order issued by the Company; 2) Service fees paid to organizations for their performance in conducting clinical trials. These expenses are determined by contracts in place for those services and communications with project managers on costs which have been incurred as of each reporting date; 3) Professional and consulting fees incurred with law firms, audit and accounting service providers and other third party consultants. These expenses are determined by either requesting those service providers to estimate unbilled services at each reporting date for services incurred, or tracking costs incurred by service providers under fixed fee arrangements. The Company has processes in place to estimate the appropriate amounts to record for accrued liabilities, which principally involve the applicable personnel reviewing the services provided. In the event that the Company does not identify certain costs which

F-19

have begun to be incurred or the Company under or over-estimates the level of services performed or the costs of such services, the reported expenses for that period may be too low or too high. The date on which certain services commence, the level of services performed on or before a given date, and the cost of such services are often judgmental. The Company makes these judgments based upon the facts and circumstances known at the date of the financial statements.

A change in the estimated cost or volume of services provided could result in additional accrued liabilities. Any significant unanticipated changes in such estimates could have a significant impact on our accrued liabilities and reported operating results. There has been no material adjustments to our accrued liabilities in any of the periods presented in the accompanying financial statements.

Accrued liabilities consist of the following:

	As of March 31,
	2007		2006
Royalty expenses	$	56,529	$	—
Payroll & payroll related costs		557,100		474,923
Research & development costs		602,615		436,016
Professional and consulting costs		400,474		320,694
Other accrued expenses		122,836		62,767
Unearned revenue		127,170		38,599
Other current liabilities		309,015		536,350
	$	2,175,739	$	1,869,349

In February 2004, the Company terminated its Licensing Agreement with ChiRhoClin. On May 9, 2005, Repligen entered into a Settlement Agreement with ChiRhoClin, Inc., in full settlement of their arbitration proceedings described below. Repligen determined that it was not required to pay approximately $1,170,000 of unremitted and accrued royalties to ChiRhoClin. This was recorded as other income in the quarter ended June 30, 2005. Under the terms of the Agreement, Repligen also received a payment of $750,000 and will be entitled to continue to market SecreFlo^®, for the next few years under a royalty structure more favorable to Repligen than under the Licensing Agreement. ChiRhoClin is obligated to deliver a certain amount of SecreFlo^®, to Repligen over the next few years. This payment of $750,000 was recorded as “Accrued Liabilities” at the time of settlement. The adoption of EITF 02-16 Accounting by a Customer (Including a Reseller) for Certain Consideration Received from a Vendor (EITF 02-16) has resulted in the Company reducing cost of goods sold as future inventory purchased from ChiRhoClin is sold. Other current liabilities as of March 31, 2007 includes $269,052 related to ChiRhoClin settlement which will be relieved as a reduction to cost of good sold as future inventory purchased from ChiRhoClin is sold.

8. Employee Benefit Plan

The Repligen Corporation 401(k) Savings and Retirement Plan (the “401(k) Plan”) is a qualified defined contribution plan in accordance with Section 401(k) of the Internal Revenue Code. All employees over the age of 21 who have completed four months of service are eligible to make pre-tax contributions up to a specified percentage of their compensation. Under the 401(k) Plan, the Company may, but is not obligated to match a portion of the employees’ contributions up to a defined maximum. The match is calculated on a calendar year basis. The Company matched $31,353, $27,278 and $34,245, for the fiscal years ended March 31, 2007, 2006, and 2005 respectively. Forfeitures of previous participants partially funded contributions for fiscal year 2007. Forfeitures of previous participants completely funded contributions for fiscal years 2006 and 2005 and as a result had no impact on the Company’s operations.

F-20

9. Related Party Transaction

Repligen paid Drs. Schimmel and Rich, the Co-Chairmen of the Board of Directors, $49,200 and $43,200, respectively, during each of the fiscal years ended March 31, 2007, 2006 and 2005 pursuant to consulting agreements, which have similar terms. These agreements are automatically extended for successive one-year terms unless terminated by either party to the agreement at least 90 days prior to the next anniversary date. Dr. Schimmel’s agreement continues until September 30, 2007 and Dr. Rich’s agreement continues until October 31, 2007. Dr. Schimmel will retire from the Board as of the next annual meeting in September 2007. Dr. Rich has advised Repligen that he has no present intention of terminating his agreement. Drs. Schimmel and Rich receive no separate cash compensation for attendance at meetings or otherwise as directors.

10. Legal Proceedings

ImClone Systems

In July 2006, Repligen reported that the United States District Court for the District of Massachusetts issued a Summary Judgment ruling in favor of Repligen and The Massachusetts Institute of Technology (“MIT”) and rejected ImClone Systems Incorporated’s (“Imclone”) defense of patent exhaustion in the ongoing patent infringement lawsuit over the production of Erbitux^®. In their complaint, Repligen and MIT allege that ImClone’s production of Erbitux^® infringes U.S. patent 4,663,281 which covers certain genetic elements that increase protein production in a mammalian cell. This patent is assigned to MIT and exclusively licensed to Repligen.

ImClone had previously reported that it produced approximately $1 billion worth of Erbitux^® prior to the expiration of the patent-in-suit in 2004 and that Bristol-Myers Squibb, ImClone’s commercial partner, has paid ImClone $900 million in up-front and milestone payments as well as a 39% royalty on the net sales of Erbitux^® in the United States.

Repligen and MIT allege that the cell line that ImClone uses to produce Erbitux^® employs key technology that is claimed in the patent-in-suit. Repligen and MIT also allege that the cell line was created under contract for the National Cancer Institute (“NCI”) by a predecessor to Repligen and subsequently transferred from the NCI to ImClone for use in research and development only. In its ruling, the Court found that neither the transfer to the NCI by Repligen’s predecessor nor the subsequent transfer to ImClone by the NCI exhausted the proprietary rights of Repligen and MIT. The Court’s ruling has eliminated these arguments as a potential defense for ImClone at trial. Repligen and MIT intend to seek damages adequate to compensate Repligen and MIT for ImClone’s unlicensed use of the patented technology and a multiplier of any such damage award based on ImClone’s willful infringement.

Bristol-Myers Squibb Company (“Bristol”)

In January 2006, Repligen Corporation and The University of Michigan jointly filed a complaint against Bristol in the United States District Court for the Eastern District of Texas for infringement of U.S. Patent No. 6,685,941 (“the ‘941 patent”) for the commercial sale of Orencia^®. The ‘941 patent, entitled “Methods of Treating Autoimmune Disease via CTLA4-Ig,” covers methods of using CTLA4-Ig to treat rheumatoid arthritis, as well as other therapeutic methods. Repligen has exclusive rights to this patent from its owners, the University of Michigan and the U.S. Navy. In February 2006, Bristol answered the complaint and counterclaimed seeking a declaratory judgment that the ‘941 patent is invalid and unenforceable and that Bristol does not infringe the patent. On November 16, 2006, the Court held a scheduling conference. Jury selection for the trial in this matter is scheduled to commence on April 7, 2008. The outcome of this case is undeterminable at this time.

From time to time, we may be subject to legal proceedings and claims, in the ordinary course of business. We are not currently aware of any such proceedings or claims that we believe will have, individually or in the aggregate, a material adverse effect on the business, financial condition or results of operations.

F-21

11. Subsequent Event

On April 6, 2007 Repligen Corporation entered into an exclusive worldwide commercial license agreement with The Scripps Research Institute (“Scripps”). Pursuant to the Agreement, the Company obtained a license to use, commercialize and sublicense certain patented technology and improvements thereon, owned or licensed by Scripps, relating to compounds which may have utility in treating Friedreich’s Ataxia, an inherited neurodegenerative disease. Research in tissues derived from patients, as well as, in mice, indicates that the licensed compounds increase production of the protein frataxin, which suggests potential utility of these compounds in slowing or stopping progression of the disease. There is currently no treatment for Friedreich’s ataxia.

Pursuant to the Agreement, the Company agreed to pay Scripps an initial license fee of $300,000, certain royalty and sublicense fees and, in the event the Company achieves specified developmental and commercial milestones, certain additional milestone payments. In addition, the Company issued Scripps 87,464 shares of the Company’s common stock (the “Shares”) representing $300,000 as of the Effective Date. If the value of the Shares does not equal at least $300,000 on the one-year anniversary of the Effective Date, the Company shall make a cash payment to Scripps equal to the difference between the actual total value of the Shares on the one-year anniversary of the Effective Date and the Effective Date. The Company issued the Shares in reliance on the exemption from registration provided by Section 4(2) of the Securities Act of 1933, as amended. The Shares were issued exclusively to Scripps as an “accredited investor” (as such term is defined in Rule 501(a) of Regulation D) without general solicitation or advertising and did not involve a public offering.

The Agreement expires or may be terminated (i) when all of the royalty obligations under the Agreement expire; (ii) at any time by mutual written consent; (iii) by Scripps if the Company (a) fails to make payments under the Agreement, (b) fails to achieve certain developmental and commercial objectives, (c) becomes insolvent, (d) is convicted of a felony relating the manufacture, use or sale of the licensed technology or (e) defaults in its performance under the Agreement; or (iv) by the Company upon 90 days written notice.

F-22

12. Selected Quarterly Financial Data (Unaudited)

The following table contains Statements of Operations information for each quarter of fiscal 2007 and 2006. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period.

	Q4 FY07			Q3 FY07			Q2 FY07			Q1 FY07			Q4 FY06			Q3 FY06			Q2 FY06			Q1 FY06
	(in thousands, except per share amounts)
Revenue:
Product revenue	$	3,397		$	3,633		$	2,680		$	3,364		$	2,842		$	2,958		$	2,716		$	4,013
Research revenue		302			249			185			264			42			30			84			226
Total revenue		3,699			3,882			2,865			3,628			2,884			2,988			2,800			4,239
Operating expenses:
Cost of revenue		902			805			915			993			889			817			872			973
Research and development		1,452			1,674			1,583			1,215			1,412			1,236			1,325			1,190
Selling, general and administrative		1,696			1,660			1,463			1,541			1,597			1,341			1,283			1,196
Total operating expenses		4,050			4,139			3,961			3,749			3,898			3,394			3,480			3,359
Income (loss) from operations		(351	)		(257	)		(1,096	)		(121	)		(1,014	)		(406	)		(680	)		880
Investment income		247			240			236			225			198			204			212			136
Interest expense		(3	)		(3	)		(3	)		(3	)		(3	)
Other income		—			—			—			—			—			—			—			1,170
Net income (loss)	$	(107	)	$	(20	)	$	(863	)	$	101		$	(819	)	$	(202	)	$	(468	)	$	2,186
Earning per share:
Basic	$	(0.00	)	$	(0.00	)	$	(0.03	)	$	(0.00	)	$	(0.03	)	$	(0.01	)	$	(0.02	)	$	0.07
Diluted	$	(0.00	)	$	(0.00	)	$	(0.03	)	$	(0.00	)	$	(0.03	)	$	(0.01	)	$	(0.02	)	$	0.07
Weighted average shares outstanding:
Basic		30,420			30,376			30,364			30,358			30,202			30,105			30,098			30,094
Diluted		30,420			30,376			30,364			30,828			30,202			30,105			30,098			30,399

13. Valuation and Qualifying Accounts

	Balance at Beginning of Period		Additions	Reversal without Utilization		Balance at End of Period
Allowance for Doubtful Accounts:
2005	$	35,000	—	$	20,000	$	15,000
2006	$	15,000	—	$	5 ,000	$	10,000
2007	$	10,000	—	$	—	$	10,000

F-23

EX-10.18

Exhibit 10.18

WHENEVER CONFIDENTIAL INFORMATION IS OMITTED HEREIN (SUCH OMISSIONS ARE DENOTED BY AN ASTERISK *), SUCH CONFIDENTIAL INFORMATION HAS BEEN SUBMITTED SEPARATELY TO THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT.

LICENSE AGREEMENT

by and between

THE SCRIPPS RESEARCH INSTITUTE,

a California nonprofit

public benefit corporation

and

REPLIGEN CORPORATION,

a Delaware corporation

TABLE OF CONTENTS

			Page
1.	Definitions		4
	1.1	Affiliate	4
	1.2	Confidential Information	4
	1.3	Field	5
	1.4	Licensed Patent Rights	5
	1.5	Licensed Product	5
	1.6	Licensed Process	5
	1.7	Licensed Service	5
	1.8	Major Market Country	5
	1.9	Net Sales	5
	1.10	Valid Claim	6
	1.11	Novartis Research Products Nonexclusive License	6
2.	Grant of License		6
	2.1	Grant of License for Licensed Products	6
	2.2	Grant of License for Licensed Processes	6
	2.3	Grant of License for Licensed Services	7
	2.4	Sublicensing	7
	2.5	No Other License	7
	2.6	Governmental Interest	7
	2.7	Reservation of Rights	7
	2.8	Novartis Non-Exclusive License	7
3.	Royalties		8
	3.1	License Issue Royalty	8
	3.2	Equity	8
	3.3	Minimum Annual Royalty	8
	3.4	Running Royalties for Licensed Products	8
	3.5	Running Royalties for Licensed Processes	8
	3.6	Running Royalties for Licensed Services	9
	3.7	Multiple Royalties	9
	3.8	Arms-Length Transactions	9
	3.9	Duration of Royalty Obligations	9
4.	Non-royalty Revenues		9
	4.1	Sublicense Revenues	9
	4.2	Product Development Milestones	10
	4.3	Certain Additional Terms	10
5.	Royalty Payments		11
	5.1	Sales by Licensee	11
	5.2	Sales by Sublicensees	11

i

6.	Reports on Progress, Benchmarks, Sales or Payments		11
	6.1	Commercial Development Plan and Benchmarks	11
	6.2	Progress Reports on Commercial Development Plan and Benchmarks	11
	6.3	Reports on Revenues and Payments	12
	6.4	Royalty Payments	13
	6.5	Foreign Sales	13
	6.6	Foreign Taxes	13
7.	Record Keeping		13
8.	Patent Matters		14
	8.1	Patent Prosecution and Maintenance	14
	8.2	Information to Licensee	14
	8.3	Patent Costs	14
	8.4	Ownership	15
	8.5	TSRI Right to Pursue Patent	15
	8.6	Infringement Actions.	15
9.	Indemnity and Insurance		16
	9.1	Indemnity	16
	9.2	Insurance	17
10.	Limited Warranty		17
	10.1	Limited Warranty	18
11.	Confidentiality and Publication		18
	11.1	Treatment of Confidential Information	18
	11.2	Publications	19
	11.3	Publicity	19
12.	Term and Termination		19
	12.1	Term	19
	12.2	Termination Upon Mutual Agreement	19
	12.3	Termination by TSRI	19
	12.4	Termination by Licensee	20
	12.5	Rights Upon Expiration	20
	12.6	Rights Upon Termination	20
	12.7	Work-in-Progress	20
	12.8	Final Royalty Report	21
13.	Assignment; Successors		21
	13.1	Assignment	21
	13.2	Binding Upon Successors and Assigns	21
14.	General Provisions		21
	14.1	Independent Contractors	21
	14.2	Late Payments	21

ii

14.3	Governmental Approvals and Marketing of Licensed Products	21
14.4	Patent Marking	21
14.5	No Use of Name	21
14.6	U.S. Manufacture	22
14.7	Foreign Registration	22
14.8	Use of Materials	22
14.9	Arbitration	22
14.10	Entire Agreement; Modification	23
14.11	California Law	23
14.12	Headings	23
14.13	Severability	24
14.14	No Waiver	24
14.15	Name	24
14.16	Attorneys’ Fees	24
14.17	Notices	24
14.18	Compliance with U.S. Laws	25

iii

LICENSE AGREEMENT

This License Agreement is entered into and made effective as of this 6^th day of April, 2007 (the “Effective Date”), by and between THE SCRIPPS RESEARCH INSTITUTE, a California nonprofit public benefit corporation (“TSRI”) located at 10550 North Torrey Pines Road, La Jolla, California 92037, and Repligen Corporation, a Delaware corporation (“Licensee”) located at 41 Seyon Street, Waltham, Massachusetts, 02453 with respect to the facts set forth below.

RECITALS

A. TSRI is engaged in fundamental scientific biomedical and biochemical research including research relating to Friedrich’s ataxia (FA).

B. Licensee is engaged in research and development of products to prevent, diagnose and treat diseases and conditions in humans.

C. TSRI has disclosed to Licensee certain technology and TSRI has the right to grant a license to the technology, subject to certain rights of the U.S. Government resulting from the receipt by TSRI of certain funding from the U.S. Government.

D. TSRI desires to grant to Licensee, and Licensee wishes to acquire from TSRI, a sole worldwide right and license to certain patent rights and materials of TSRI, subject to the terms and conditions set forth herein.

AGREEMENT

NOW, THEREFORE, in consideration of the mutual covenants and conditions set forth herein, TSRI and Licensee hereby agree as follows:

1. Definitions. Capitalized terms shall have the meaning set forth herein.

1.1 Affiliate. The term “Affiliate” shall mean any entity which directly or indirectly controls, or is controlled by Licensee. The term “control” as used herein means (a) in the case of corporate entities, direct or indirect ownership of at least fifty percent (50%) of the stock or shares entitled to vote for the election of directors; or (b) in the case of non-corporate entities, direct or indirect ownership of at least fifty percent (50%) of the equity interest with the power to direct the management and policies of such non-corporate entities. Unless otherwise specified, the term Licensee includes Affiliates.

1.2 Confidential Information. The term “Confidential Information” shall mean any and all proprietary or confidential information of TSRI or Licensee which may be exchanged between the parties at any time and from time to time during the term of this Agreement. Information shall not be considered confidential to the extent that the receiving party can establish by competent proof that it:

(a) Is publicly disclosed through no fault of any party hereto, either before or after it becomes known to the receiving party; or

(b) Was known to the receiving party prior to the date of this Agreement, which knowledge was acquired independently and not from another party hereto (or such party’s employees); or

(c) Is subsequently disclosed to the receiving party in good faith by a third party who has a right to make such disclosure; or

(d) Has been published by a third party as a matter of right.

1.2.1 In the event that Confidential Information is required to be disclosed by law or court order, in which event the party required to make such disclosure shall limit the same to the minimum required to comply with the law or court order, and prior to making such disclosure that party shall notify the other party, not later than ten (10) days before the disclosure in order to allow that other party to comment and/or to obtain a protective or other order, including extensions of time and the like, with respect to such disclosure.

1.3 Field. The term “Field” shall mean the prevention, diagnosis and treatment of conditions or diseases in humans.

1.4 Licensed Patent Rights. The term “Licensed Patent Rights” shall mean rights arising out of or resulting from (a) the U.S./PCT Patent Application(s) set forth on Exhibit A; (b) the foreign patent applications of (a); (c) the patents proceeding from (a) and (b); (d) divisionals, continuations, reissues, reexaminations, and extensions of any patent or application set forth in (a)- (c) above; and (e) all claims of continuations-in-part that are entitled to the benefit of the priority date of (a).

1.5 Licensed Product. The term “Licensed Product” shall mean any product, the manufacture, use, importation, sale or offer for sale of which in or into a particular country is covered by a Valid Claim within the Licensed Patent Rights. Whether a product is a “Licensed Product” shall be determined on a country-by-country basis.

1.6 Licensed Process. The term “Licensed Process” shall mean any process, the performance of which is covered by a Valid Claim of Licensed Patent Rights. Whether a process is a “Licensed Process” shall be determined on a country-by-country basis.

1.7 Licensed Service. The term “Licensed Service” shall mean the performance of a service by Licensee or a sublicensee for a third party, which performance uses or incorporates a Licensed Product or Licensed Process. Whether a service is a “Licensed Service” shall be determined on a country-by-country basis.

1.8 Major Market Country. The term “Major Market Country” shall mean any of the following countries: the United States of America, the United Kingdom, France, Germany, Spain, Italy, Japan, Canada, or Australia.

1.9 Net Sales. The term “Net Sales” shall mean the gross amount invoiced by Licensee, or sublicensee, or any of them on all sales of Licensed Products, Licensed Processes and Licensed Services less (a) discounts, chargebacks and rebates actually allowed, whether in cash or trade; (b) credits for claims, allowances, retroactive price reductions or returned goods;

(c) prepaid freight and insurance; and (d) sales taxes or other governmental charges actually paid in connection with sales of Licensed Products (but excluding what are commonly known as income taxes and value-added taxes). Net Sales shall include all consideration charged by Licensee or sublicensees in exchange for any Licensed Products, Licensed Processes, or Licensed Services, including without limitation any monetary payments or any other property whatsoever. For purposes of determining Net Sales, a sale shall be deemed to have occurred when an invoice therefore shall be generated or the Licensed Product shipped for delivery, Licensed Process, completed, or Licensed Service provided. Sales of Licensed Products by Licensee to any Affiliate or sublicensee which is a reseller thereof shall be excluded, and only the subsequent sale of such Licensed Products by Affiliates or sublicensees of Licensee to unrelated parties shall be deemed to generate Net Sales hereunder.

1.10 Valid Claim. The term “Valid Claim” shall mean a claim of an issued patent within the Licensed Patent Rights that has not lapsed, expired, been canceled, or become abandoned, and has not been held invalid by a court or other appropriate body of competent jurisdiction, unappealable or unappealed within the time allowed for appeal and which has not been admitted to be invalid or unenforceable through reissue or disclaimer or otherwise. The term Valid Claim shall also include the claims of a pending patent application within the Licensed Patent Rights for a period of six (6) years from the date of first examination (i.e., first office action) of that patent application.

1.11 Novartis Research Products Nonexclusive License. “Novartis Research Products Nonexclusive License” shall mean the non-exclusive, worldwide license rights (without the right to sublicense) granted by Scripps to Novartis under the Licensed Patent Rights to make and use (but not sell) “Research Products”. “Research Products” is defined to mean any product, process or device which is designed or utilized for discovering, improving or testing a Therapeutic Product, Preventative medicine, or Diagnostic Product. “Diagnostic Product” means any product, process or device that is designed or utilized for diagnosis of a disease or condition in humans or vertebrate animals. “Preventative medicine” means any product, process or device that is designed or utilized to prevent the occurrence of any disease state in humans or vertebrate animals. “Therapeutic Product” means any product, process or device which is designed or utilized for treatment or mitigation of an existing disease state in humans or vertebrate animals.

2. Grant of License.

2.1 Grant of License for Licensed Products. TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, a sole license under the Licensed Patent Rights to make and have made, to use and have used and to import Licensed Products in the Field. In addition, TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, an exclusive license under the Licensed Patent Rights to offer to sell, to sell and have sold Licensed Products in the Field.

2.2 Grant of License for Licensed Processes. TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, a sole license under the Licensed Patent Rights to use and have used Licensed Processes in the Field. In addition, TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, an exclusive

license under the Licensed Patent Rights to offer to sell, to sell and have sold Licensed Processes in the Field.

2.3 Grant of License for Licensed Services. TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, a sole license under the Licensed Patent Rights to use and have used Licensed Services in the Field. In addition, TSRI hereby grants and Licensee accepts, subject to the terms and conditions of this Agreement, an exclusive license under the Licensed Patent Rights to offer to sell, to sell and have sold Licensed Services in the Field.

2.4 Sublicensing. Licensee shall have the right to grant and authorize sublicenses to any party with respect to the rights conferred upon Licensee under this Agreement, provided, however, that any such sublicense shall be subject in all respects to the provisions contained in this Agreement (excluding the payments specified in Sections 3.1 and 3.2 below). Sublicensees shall not further sublicense without TSRI’s prior written consent, which approval shall not be unreasonably withheld. Licensee shall forward to TSRI a copy of any and all fully executed agreements within thirty (30) days of execution.

2.5 No Other License. This Agreement confers no license or rights by implication, estoppel, or otherwise under any patent applications or patents of TSRI other than Licensed Patent Rights regardless of whether such patents are dominant or subordinate to Licensed Patent Rights. TSRI and Licensee hereby agree and acknowledge that nothing in this Agreement, including without limitation the provisions of Sections 2.6, 2.7, and 2.8, create, expressly or implicitly, any obligation for Licensee to grant any rights or licenses, or to provide any materials or perform any services, to or for TSRI or any Third Party, including without limitation, the United States Government or Novartis.

2.6 Governmental Interest. Licensee and TSRI acknowledge that TSRI has received, and expects to continue to receive, funding from the United States Government in support of TSRI’s research activities. Licensee and TSRI acknowledge and agree that their respective rights and obligations pursuant to this Agreement shall be subject to the rights of the United States Government, which may exist, arise or result from TSRI’s receipt of research support from the United States Government, including but not limited to, 37 C.F.R. 401, the NIH Grants Policy Statement and the NIH Guidelines for Obtaining and Disseminating Biomedical Research Resources.

2.7 Reservation of Rights. TSRI reserves the right to use for any research or educational purposes any Licensed Patent Rights and materials licensed hereunder, without TSRI being obligated to pay Licensee any royalties or other compensation. In addition, TSRI reserves the right to grant non-exclusive research and educational use licenses to other nonprofit or academic institutions to Licensed Patent Rights licensed hereunder, without the other nonprofit entity being obligated to pay Licensee any royalties or other compensation. TSRI shall have no obligation to notify or inform Licensee of such use or licenses.

2.8 Novartis Non-Exclusive License. The licenses granted under Sections 2.1 and 2.2 of this Agreement are subject to the non-exclusive license rights granted to Novartis pursuant to the Novartis Research Products Nonexclusive License.

3. Royalties

3.1 License Issue Royalty. In consideration for TSRI entering into this Agreement, Licensee agrees to pay and shall pay to TSRI a noncreditable, nonrefundable license issue royalty in the amount of Three Hundred Thousand U.S. Dollars (U.S.$300,000) (“License Issue Royalty”) within fifteen (15) days of the Effective Date. Failure of Licensee to make this payment shall render this Agreement null and void (ab initio).

3.2 Equity. In addition to the License Issue Royalty specified in 3.1 above, Licensee shall issue to TSRI Eighty Seven Thousand Four Hundred Sixty-Four (87,464) shares of Licensee’s common stock, equal to Three Hundred Thousand U.S. Dollars (U.S. $300, 000) within fifteen (15) days of the Effective Date as reported on the Nasdaq Global Market or such other market on which such shares are then traded. Each share of Licensee common stock shall be valued at the closing price of such shares on the trading day immediately prior to the Effective Date. If the value of the shares is not equal to Three Hundred Thousand U.S. Dollars (U.S. $300,000) on the one-year anniversary of the Effective Date, Licensee shall make a cash payment to TSRI equal to the difference between the actual total value of the shares on such date and Three Hundred Thousand U.S. Dollars (U.S. $300,000) within thirty (30) days after the one year anniversary of the Effective Date.

3.3 Minimum Annual Royalty. Subject to the credits described in this Section 3.3, within thirty days following each anniversary of the Effective Date, Licensee agrees to pay and shall pay to TSRI a nonrefundable minimum annual royalty in the amount of [**Confidential Treatment Requested**] for the twelve (12) month period immediately preceding such anniversary date. Each such minimum annual royalty shall be offset (i.e., reduced by) by any amounts paid, as specified in 3.4, 3.5, 3.6, 4.1, and 4.2. hereunder by Licensee during the twelve (12) month period immediately preceding the relevant anniversary date.

3.4 Running Royalties for Licensed Products. Licensee agrees to pay and shall pay to TSRI a running royalty on a country by country basis in the amount of [**Confidential Treatment Requested**] of Net Sales of Licensed Products. Licensee shall be entitled to a credit against royalties due hereunder, of [**Confidential Treatment Requested**] of any royalties paid to any third parties by Licensee, its Affiliates or sublicensees which is necessary in order for Licensee or its Affiliates or sublicensees to make, use, sell, offer for sale, or import any Licensed Product without infringing any patent or other rights of such third party. The application of such credit shall be limited so that it shall not reduce by more than [**Confidential Treatment Requested**] the royalties paid hereunder for any given period.

3.5 Running Royalties for Licensed Processes. Licensee agrees to pay and shall pay to TSRI a running royalty on a country by country basis in the amount of [**Confidential Treatment Requested**] of Net Sales of products made using a Licensed Process. Licensee shall be entitled to a credit against royalties due hereunder, of [**Confidential Treatment Requested**] of any royalties paid to any third parties by Licensee, its Affiliates or sublicensees which is necessary in order for Licensee or its Affiliates or sublicensees to make, use, sell, offer for sale or perform any Licensed Process without infringing any patent or other rights of such third party. The application of such credit shall be limited so that it shall not reduce by more than [**Confidential Treatment Requested**] the royalties paid hereunder for any given period.

3.6 Running Royalties for Licensed Services. Licensee agrees to pay and shall pay to TSRI [**Confidential Treatment Requested**] of any and all Net Sales for Licensed Services. Licensee shall be entitled to a credit against royalties due hereunder, of [**Confidential Treatment Requested**] of any royalties paid to any third parties by Licensee, its Affiliates or sublicensees which is necessary in order for Licensee or its Affiliates or sublicensees to make, use, sell, offer for sale or perform any Licensed Service without infringing any patent or other rights of such third party. The application of such credit shall be limited so that it shall not reduce by more than [**Confidential Treatment Requested**] the royalties paid hereunder for any given period.

3.7 Multiple Royalties. No multiple royalties shall be due because any Licensed Product, Licensed Process or Licensed Service is covered by more than one of the Licensed Patent Rights. In such case, Licensee shall pay the highest of the royalties owed to TSRI pursuant to Sections 3.4-3.6 above.

3.8 Arms-Length Transactions. On sales of Licensed Products, Licensed Processes or Licensed Services which are made in other than an arm’s-length transaction, the value of the Net Sales attributed under this Section 3 to such a transaction shall be that which would have been received in an arm’s-length transaction, based on sales of like quality and quantity products on or about the time of such transaction. “Arm’s-length transaction” means a sale between unaffiliated parties.

3.9 Duration of Royalty Obligations. The royalty obligations of Licensee as to each Licensed Product, Licensed Process or Licensed Service shall terminate on a country-by-country basis concurrently with the expiration or termination of the last Valid Claim within Licensed Patent Rights that covers such Licensed Product or Licensed Process or Licensed Service.

4. Non-royalty Revenues.

4.1 Sublicense Revenues. Any and all revenues, other than royalties, research and development funding (excluding Licensed Services), and equity investments made by such sublicensees in Licensee’s stock, pursuant to a stock purchase agreement that is separate from the sublicense agreement, to the extent such stock was sold by Licensee for a price that is above the then-current fair market value (for avoidance of doubt, the amount above fair market value shall be included within Sublicense Revenue as defined herein). Sublicense Revenue shall be reported and paid to TSRI by Licensee within thirty (30) days of receipt by Licensee as provided herein. Licensee shall pay to TSRI a non-creditable, non-refundable percentage of these Sublicense Revenues according to the following schedule (“Sublicense Payments”):

Effective Date of Sublicense Agreement	Percent of Sublicense Revenues Payable to TSRI
First period of six months after Effective Date	[**Confidential Treatment Requested**]
Second period of six months after Effective Date	[**Confidential Treatment Requested**]

Third period of six months after Effective Date	[**Confidential Treatment Requested**]
Fourth period of six months after Effective Date	[**Confidential Treatment Requested**]
During the third year after Effective Date	[**Confidential Treatment Requested**]
During or after the fourth year after Effective Date	[**Confidential Treatment Requested**]

Any non-cash consideration received by Licensee from sublicensees shall be valued at its fair market value as of the date of receipt.

4.2 Product Development Milestones. Licensee agrees to pay and shall pay to TSRI the following non-creditable, non-refundable product development milestones within thirty (30) days of the first achievement of each milestone with a Licensed Product. All such milestones shall be payable a maximum of one time each regardless of how many times each is achieved in a particular country and regardless of in how many countries each is achieved.

Milestone Event	Payment
First Patient Dosed in a Clinical Trial in a Major Market Country	[**Confidential Treatment Requested**]
First Patient Dosed in a Phase III Trial (or its equivalent) in a Major Market Country	[**Confidential Treatment Requested**]
Acceptance of NDA Filing by the FDA (or its equivalent) in a Major Market Country	[**Confidential Treatment Requested**]
FDA Approval of an NDA to treat Friedrich’s Ataxia	[**Confidential Treatment Requested**]
FDA Approval of an NDA to treat a disease other than Friedrich’s Ataxia	[**Confidential Treatment Requested**]
European Approval in a Major Market Country	[**Confidential Treatment Requested**]

4.3 Certain Additional Terms. After Licensee executes its first sublicense pursuant to Section 2.4, all amounts that Licensee thereafter pays to TSRI under Section 4.2 shall be fully credited only against the Sublicense Payments due from Licensee to TSRI under Section 4.1 for product development milestone payments that Licensee subsequently receives from its sublicensees under sublicense agreements (“Sublicensee Milestone Payments”). The payments

that Licensee makes to TSRI under Section 4.2 shall not be credited or applied against any other Sublicense Payments due from Licensee to TSRI under Section 4.1. In order to receive such credit, Licensee shall itemize in detail on its accounting of Sublicense Revenues under Section 4.1 the original amount of Sublicense Payments due under Section 4.1 for Sublicensee Milestone Payments for each sublicense, and the specific amounts paid to TSRI under Section 4.2 after the date of Licensee’s first sublicense that Licensee wants credited against its Sublicense Payments due under Section 4.1 for Sublicensee Milestone Payments for each sublicense. If any amounts required to be paid to TSRI under Section 4.2 are due before Licensee executes its first sublicense, but are not actually paid by Licensee to TSRI until after Licensee executes its first sublicense, then those amounts actually paid by Licensee to TSRI under Section 4.2 shall not be entitled to be credited or applied against Sublicense Payments due under Section 4.1 for Sublicensee Milestone Payments for any sublicense.

5. Royalty Payments.

5.1 Sales by Licensee. Royalties payable pursuant to Section 3 herein, shall be payable by Licensee quarterly, within sixty (60) days after the end of each calendar quarter, based upon Net Sales during the immediately preceding calendar quarter.

5.2 Sales by Sublicensees. Licensee agrees to pay and shall pay to TSRI, or cause its sublicensees to pay to TSRI all royalties pursuant to Section 3 herein resulting from the activities of its sublicensees, within ninety (90) days after the end of each calendar quarter.

6. Reports on Progress, Benchmarks, Sales or Payments.

6.1 Commercial Development Plan and Benchmarks. Prior to signing this Agreement, Licensee has provided to TSRI the Commercial Development Plan attached hereto as Exhibit B, under which Licensee intends to bring the subject matter of the Licensed Patent Rights to the point of commercial use. This Commercial Development Plan is hereby incorporated by reference into this Agreement. Based on this plan, performance Benchmarks are determined as specified in Exhibit C.

6.2 Progress Reports on Commercial Development Plan and Benchmarks. Licensee shall provide written annual reports on its product development progress or efforts to commercialize under the Commercial Development Plan for each of the Fields within thirty (30) days after June 30 of each year. These progress reports shall include, but not be limited to: progress on research and development, status of applications for regulatory approvals, manufacturing, sublicensing, marketing, importing, and sales during the preceding calendar year, as well as plans for the present calendar year. TSRI also encourages these reports to include information on any of Licensee’s public service activities that relate to the Licensed Patent Rights. If reported progress differs from that projected in the Commercial Development Plan and Benchmarks, Licensee shall explain the reasons for such differences. In any such annual report, Licensee may propose amendments to the Commercial Development Plan, acceptance of which by TSRI may not be denied unreasonably. Licensee agrees to provide any additional information reasonably required by TSRI to evaluate Licensee’s performance under this Agreement. Licensee may amend the Benchmarks at any time upon written consent by TSRI. TSRI shall not unreasonably withhold approval of any request by Licensee to extend the time periods of this

schedule if such request is supported by a reasonable showing by Licensee of diligence in its performance under the Commercial Development Plan and toward bringing the Licensed Products to the point of commercial use. Licensee shall amend the Commercial Development Plan and Benchmarks at the request of TSRI to address any Licensed Fields not specifically addressed in the plan originally submitted.

6.2.1 At any time after two (2) years from the Effective Date of this Agreement, if TSRI, in its sole reasonable judgment, believes progress reports furnished by Licensee do not demonstrate that Licensee: (a) has put the licensed subject matter into commercial use in at least one Major Market Country, directly or through a sublicense, and is keeping the licensed subject matter reasonably available to the public; or (b) is engaged in research, development, manufacturing, marketing or sublicensing activity reasonably intended to achieving 6.2.1(a), then TSRI may terminate this Agreement, provided that TSRI shall provide express written notice to Licensee explaining in reasonably specific detail the reasons for such belief, and Licensee shall have not less than sixty (60) days to cure the applicable diligence failure or provide to TSRI evidence in support of Licensee’s diligence efforts. Licensee shall report to TSRI the dates for achieving Benchmarks specified in Exhibit C and the first commercial sale of a Licensed Product, Licensed Service, and Licensed Process in each country within thirty (30) days of such occurrences.

6.3 Reports on Revenues and Payments. Licensee shall submit to TSRI, no later than sixty (60) days after then end of each calendar quarter, a royalty report (the “Royalty Report”) setting forth for such quarter at least the following information:

(a) the number of Licensed Products sold by Licensee, and its sublicensees;

(b) the total Net Sales for such Licensed Products;

(c) the total Net Sales for all Licensed Processes used or sold by Licensee and its sublicensees;

(d) the total Net Sales for all Licensed Services performed;

(e) deductions applicable to determine the Net Sales pursuant to Section 1.10;

(f) the total amount of third party royalties paid, if any, and the calculation of the royalty credit under Sections 3.4, 3.5, and 3.6;

(g) the amount of Sublicense Revenues received by Licensee; and

(h) the amount of royalty due on all of the above, or if no royalties are due to TSRI for any reporting period, the statement that no royalties are due and a detailed explanation why they are not due for that quarterly period.

Such Royalty Report shall be certified as correct by an officer of Licensee and shall include a detailed listing of all deductions from royalties.

6.4 Royalty Payments. Licensee agrees to pay and shall pay to TSRI with each Royalty Report the amount of royalty due with respect to such quarter. If multiple technologies are covered by the license granted hereunder, Licensee shall specify which Licensed Patent Rights are utilized for each Licensed Product, Licensed Process, and/or Licensed Service included in the Royalty Report. All payments due hereunder shall be deemed received when funds are credited to TSRI’s bank account and shall be payable by check or wire transfer in United States Dollars.

6.5 Foreign Sales. The remittance of royalties payable on sales outside the United States shall be payable to TSRI in United States Dollar equivalents at the official rate of exchange of the currency of the country from which the royalties are payable, as quoted in the Wall Street Journal for the last business day of the calendar quarter in which the royalties are payable. If the transfer of or the conversion into the United States Dollar equivalents of any such remittance in any such instance is not lawful or possible, the payment of such part of the royalties as is necessary shall be made by the deposit thereof, in the currency of the country where the sale was made on which the royalty was based to the credit and account of TSRI or its nominee in any commercial bank or trust company of TSRI’s choice located in that country, prompt written notice of which shall be given by Licensee to TSRI.

6.6 Foreign Taxes. Any tax required to be withheld by Licensee under the laws of any foreign country for any royalties or other amount due hereunder or for the accounts of TSRI shall be promptly paid by Licensee for and on behalf of TSRI to the appropriate governmental authority, and Licensee shall furnish TSRI with proof of payment of such tax together with official or other appropriate evidence issued by the applicable government authority. Any such tax actually paid on TSRI’s behalf shall be deducted from royalty payments due TSRI.

7. Record Keeping. Licensee shall keep, and shall require its Affiliates and sublicensees to keep, accurate records (together with supporting documentation) of Licensed Products, Licensed Processes and Licensed Services made, used or sold under this Agreement, appropriate to determine the amount of royalties, Sublicense Payments, Product Development Milestone Payments and other monies due to TSRI hereunder. Such records shall be retained for at least five (5) years following the end of the reporting period to which such records relate. They shall be available during normal business hours for examination and copying by an accountant selected by TSRI, for the purpose of verifying Licensee’s reports and payments hereunder and its compliance with this Agreement. In conducting examinations pursuant to this Section, TSRI’s accountant shall have access to, and may disclose to TSRI, all records which TSRI reasonably believes to be relevant to the calculation of royalties under Section 3, non-royalty revenues under Section 4 and Licensee’s compliance with this Agreement.

Except as set forth above, TSRI’s accountant shall not disclose to TSRI any information other than information relating to the accuracy of reports and payments made hereunder and to Licensee’s compliance with this Agreement.

Such examination by TSRI’s accountant shall be at TSRI’s expense, provided that, if such examination shows an underreporting or underpayment in excess of five percent (5%) for any twelve (12) month period, then Licensee shall pay the cost of such examination (including without limitation TSRI’s attorney’s fees, accountant’s fees, and other costs) as well as any

additional sum that would have been payable to TSRI had the Licensee reported correctly, plus interest on said sum at the rate of one and one-half percent (1-1/2%) per month, and provided further, that if a second underreporting or underpayment in excess of five percent (5%) for any twelve (12) month period occurs, then the interest payable on such sum shall be calculated and payable at the rate of two percent (2%) per month. All payments due hereunder shall be made within fifteen (15) days of receipt of a written demand from TSRI.

8. Patent Matters.

8.1 Patent Prosecution and Maintenance. From and after the date of this Agreement, the provisions of this Section 8 shall control the prosecution and maintenance of any patent and patent application included within Licensed Patent Rights. Subject to the requirements, limitations, and conditions set forth in this Agreement, TSRI shall (a) direct and control the preparation, filing and prosecution of the United States and foreign patent applications within Licensed Patent Rights (including without limitation any reissues, reexaminations, appeals to appropriate patent offices and/or courts, interferences and foreign oppositions); and (b) maintain the patents issuing therefrom. TSRI shall select the patent attorney, subject to Licensee’s written approval, which approval shall not be unreasonably withheld. Both parties hereto agree that TSRI may, at its sole discretion, utilize TSRI’s Office of Patent Counsel in lieu of or in addition to independent counsel for patent prosecution and maintenance described herein, and the fees and expenses incurred by TSRI with respect to work done by such Office of Patent Counsel and/or independent counsel shall be paid as set forth below. Licensee shall have full rights of consultation with the patent attorney so selected on all matters relating to Licensed Patent Rights. TSRI shall use its best efforts to implement all reasonable and timely requests made by Licensee with regard to the preparation, filing, prosecution and/or maintenance of the patent applications and/or patents within Licensed Patent Rights.

8.2 Information to Licensee. TSRI shall keep Licensee timely informed of the progress of all patent applications, patents and other submissions relating thereto and give Licensee and Licensee’s counsel reasonable opportunity to review and comment on the text of each patent application within Licensed Patent Rights and other submissions relating thereto before filing, including, but not limited to, the type and scope of the useful claims and the nature of supporting disclosures. TSRI shall provide Licensee with a copy of such patent application as filed, together with notice of its filing date and serial number, and each such submission. TSRI shall provide Licensee with copies of all patent applications, amendments, related correspondence, and other relevant documentation relating to such prosecution.

8.3 Patent Costs. Licensee acknowledges and agrees that the license granted hereunder is in partial consideration for Licensee’s assumption of patent costs and expenses as described herein. Licensee agrees to reimburse and shall reimburse TSRI Twenty Four Thousand Six Hundred Forty Three Dollars ($24,643.00) for all patent fees and expenses previously paid or incurred in connection with Licensed Patent Rights which are as of October 31, 2006. Licensee agrees to pay and shall pay all such past fees, costs, and future cost and patent fees associated with the work performed by TSRI’s Office of Patent Counsel and/or Independent Counsel to prepare, prosecute, and maintain the Licensed Patent Rights within thirty (30) days after Licensee receives an itemized invoice therefor. Failure of Licensee to pay patent costs and expenses as set forth in this Section 8.3 shall immediately relieve TSRI from its obligation to

incur any further patent costs and expenses. For the avoidance of doubt, should Licensee be in arrears for any patent costs and expenses due to TSRI for independent counsel, TSRI shall have the right, at its sole discretion, to cease all patent prosecution and allow Licensed Patent Rights to go abandoned. Such action by TSRI shall not constitute a breach of this Agreement. Payment can be made directly to independent counsel, or to TSRI, as the Parties may agree. Licensee may elect with a minimum of ninety (90) days prior written notice to TSRI, to discontinue payment for the filing, prosecution and/or maintenance of any patent application and/or patent within Licensed Patent Rights. Licensee shall remain liable for all patent prosecution and maintenance costs incurred prior to the date of notice of election and for a ninety (90) day period following date of such notice. Any such patent application or patent so elected shall immediately be excluded from the definition of Licensed Patent Rights and from the scope of the licenses granted under this Agreement, and all rights relating thereto shall revert to TSRI and may be freely licensed by TSRI.

8.4 Ownership. The patent applications filed and the patents obtained by TSRI pursuant to Section 8.1 hereof shall be owned solely by TSRI, assigned solely to TSRI and deemed a part of Licensed Patent Rights.

8.5 TSRI Right to Pursue Patent. If at any time during the term of this Agreement, Licensee’s rights with respect to Licensed Patent Rights are terminated, TSRI shall have the right to take whatever action TSRI deems appropriate to obtain or maintain the corresponding patent protection. If TSRI pursues patents under this Section 8.5, Licensee agrees to cooperate fully, including by providing, at no charge to TSRI, all appropriate technical data and executing all necessary legal documents.

8.6 Infringement Actions.

8.6.1 Licensee and TSRI each shall inform the other promptly in writing of any alleged infringement by a third party of the Licensed Patent Rights covering Licensed Products, Licensed Services, and/or Licensed Processes which comes to the its attention and of any reasonably available evidence thereof.

8.6.2 Prosecution of Infringements. During the term of this Agreement, the parties shall consult with each other regarding such infringement of any patent within such Licensed Patent Rights. In order to maintain the licenses granted hereunder in force, Licensee shall prosecute any and all infringements of any Licensed Patent Rights by third parties, unless such infringement is outside of the Field or is economically immaterial. Licensee may enter into settlements, stipulated judgments or other arrangements respecting such infringement, at its own expense, but only with the prior written consent of TSRI, which consent shall not be unreasonably withheld. TSRI shall permit any action to be brought in its name if required by law, and Licensee shall hold TSRI harmless from any costs, expenses or liability respecting all such infringements. TSRI agrees to provide reasonable assistance of a technical nature which Licensee may require in any litigation arising in accordance with the provisions of this Section 8.6.2, for which Licensee shall pay to TSRI a reasonable hourly rate of compensation. In the event Licensee fails to prosecute any such infringement, Licensee shall notify TSRI in writing promptly and TSRI shall have the right, but not the obligation, to prosecute such infringement on its own behalf.

8.6.3 Allocation of Recovery. Any damages or other recovery from an infringement action undertaken pursuant to Section 8.6.2 shall first be used to reimburse the parties for the costs and expenses incurred in such action, and thereafter: (a) the amount attributable to compensatory damages shall be treated as Net Sales and allocated pursuant to Section 3; and (b) all non-compensatory damages (whether denoted at punitive or a statutory penalty) shall be divided seventy percent (70%) to Licensee and thirty (30%) to TSRI. If TSRI prosecutes any such action under Section 8.6.2, then any damages or other recovery net of the parties’ costs and expenses incurred in such infringement shall be the sole property of TSRI.

9. Indemnity and Insurance.

9.1 Indemnity. Licensee hereby agrees to indemnify, defend (by counsel reasonably acceptable to TSRI) and hold harmless TSRI and any parent, subsidiary or other affiliated entity and their trustees, directors, officers, employees, scientists, agents, successors, assigns and other representatives (collectively, the “Indemnitees” from and against all damages, claims, liabilities, losses and other expenses, including without limitation reasonable attorney’s fees, expert witness fees and costs , arising from claims asserted by third parties (“Claim”), that arise out of or relate to (a) Licensee’s or any sublicensee’s use of any of the Licensed Patent Rights, (b) alleged defects or other problems with any of the Licensed Products, Licensed Processes, or Licensed Services manufactured, sold, distributed or rendered by Licensee or any sublicensee, including without limitation any personal injuries, death or property damages related thereto, (c) any advertising or other promotion of the Licensed Products, Licensed Processes, or Licensed Services by Licensee or any sublicensees, (d) any allegations that the Licensed Products, Licensed Processes, or Licensed Services developed, manufactured, sold, distributed or rendered by Licensee or any sublicensee and/or any trademark, service mark, logo, symbol, slogan or other materials used in connection with or to market a Licensed Product, Licensed Process, or Licensed Service violates or infringes upon the trademarks, service marks, trade dress, trade names, copyrights, patents, works of authorship, inventorship rights, trade secrets, database rights, rights under unfair competition laws, rights of publicity, privacy or defamation, or any other intellectual or industrial property rights of any third party, (e) Licensee’s or any sublicensee’s failure to comply with any applicable laws, rules or regulations, (f) Licensee’s or any sublicensee’s transactions with third parties or the operation of their respective businesses, and/or (g) the negligent or willful acts or omissions of Licensee or any sublicensee; provided that to the extent any Claim arises out of any negligent action, or failure to act, by TSRI or TSRI’s breach of any law or regulation, or breach of this Agreement by TSRI, Licensee’s liability for damages will be proportioned to the extent of the respective fault of Licensee and TSRI. Licensee shall not enter into any settlement of such Claims that admits liability on behalf of TSRI without TSRI’s prior written consent. Indemnitees, at their expense, shall have the right to retain separate independent counsel to assist in defending any such Claims. In the event Licensee fails to promptly indemnify and defend such Claims and/or pay Indemnitees’ expenses as provided above, Indemnitees shall have the right to defend themselves, and in that case, Licensee shall reimburse Indemnitees for all of their reasonable attorney’s fees, costs and damages incurred in settling or defending such Claims within thirty (30) days of each of Indemnitees’ written requests. This indemnity shall be a direct payment obligation and not merely a reimbursement obligation of Licensee to Indemnitees.

9.2 Insurance. Licensee shall name TSRI and Indemnitees as “additional insureds” on any commercial general liability and product liability insurance policies maintained by Licensee, its Affiliates and sublicensees applicable to the Licensed Products, Licensed Services, and Licensed Processes.

9.2.1 Beginning at the time any such Licensed Product, Licensed Process, Licensed Service, or Licensed Material is being commercially distributed or sold (other than for the purpose of obtaining regulatory approvals) by Licensee or by a sublicensee, Licensee shall, at its sole cost and expense, procure and maintain commercial general liability insurance in amounts not less than $2,000,000 per incident and $2,000,000 annual aggregate and naming the Indemnitees as additional insureds. During clinical trials of any such product, process or service, Licensee shall, at its sole cost and expense, procure and maintain commercial general liability insurance in such equal or lesser amount as TSRI shall require, naming the Indemnitees as additional insureds. Such commercial general liability insurance shall provide (i) product liability coverage; (ii) broad form contractual liability coverage for Licensee’s indemnification under this Agreement; and (iii) coverage for TSRI’s litigation costs. If Licensee elects to self-insure all or part of the limits described above (including deductibles or retentions which are in excess of $250,000 annual aggregate) such self-insurance program must be acceptable to TSRI in its sole discretion. The insurance coverage amounts specified herein or the maintenance of such insurance policies shall not in any way limit Licensee’s indemnity or other liability under this Agreement.

9.2.2 In addition, Licensee, on behalf of itself and its insurance carriers, waives any and all claims and rights of recovery against TSRI and the Indemnitees, including without limitation all rights of subrogation, with respect to either party’s performance under this Agreement or for any loss of or damage to Licensee or its property or the property of others under its control. Licensee’s commercial general liability insurance policy shall also include a waiver of subrogation consistent with this paragraph in favor of TSRI and the Indemnitees. Licensee shall be responsible for obtaining such waiver of subrogation from its insurance carrier. Upon TSRI’s request, Licensee shall deliver to TSRI copies of insurance certificates or binders and such waiver of subrogation that complies with the requirements of this Section 9.

9.2.3 Licensee shall provide TSRI with written evidence of such insurance upon request of TSRI. Licensee shall provide TSRI with written notice at least fifteen (15) days prior to the cancellation, non-renewal or material change in such insurance; if Licensee does not obtain replacement insurance providing comparable coverage within such fifteen (15) day period, TSRI shall have the right to terminate this Agreement effective at the end of such fifteen (15) day period without notice or any additional waiting periods.

9.2.4 Licensee shall maintain such commercial general liability insurance beyond the expiration or termination of this Agreement during (a) the period that any Licensed Product or Licensed Service relating to, or developed pursuant to, this Agreement is being commercially distributed or sold by Licensee or by a sublicensee, Affiliate or agent of Licensee; and (b) a reasonable period after the period referred to in Section 9.2.4 (a) above which in no event shall be less than fifteen (15) years.

10. Limited Warranty.

10.1 Limited Warranty. TSRI hereby represents and warrants that it has full right and power to enter into this Agreement and that the Licensed Patent Rights have been prosecuted in good faith by TSRI. TSRI MAKES NO OTHER WARRANTIES CONCERNING LICENSED PATENT RIGHTS OR ANY OTHER MATTER WHATSOEVER, INCLUDING WITHOUT LIMITATION ANY EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT OF THIRD PARTY RIGHTS OR ARISING OUT OF COURSE OF CONDUCT OR TRADE CUSTOM OR USAGE, AND TSRI DISCLAIMS ALL SUCH EXPRESS OR IMPLIED WARRANTIES. TSRI MAKES NO WARRANTY OR REPRESENTATION AS TO THE VALIDITY OR SCOPE OF LICENSED PATENT RIGHTS, OR THAT ANY LICENSED PRODUCT OR LICENSED SERVICE WILL BE FREE FROM AN INFRINGEMENT ON PATENTS OR OTHER INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES, OR THAT NO THIRD PARTIES ARE IN ANY WAY INFRINGING UPON ANY LICENSED PATENT RIGHTS COVERED BY THIS AGREEMENT. FURTHER, TSRI HAS MADE NO INVESTIGATION AND MAKES NO REPRESENTATION THAT THE LICENSED PATENT RIGHTS ARE SUITABLE FOR LICENSEE’S PURPOSES.

IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS OR EXPECTED SAVINGS OR OTHER ECONOMIC LOSSES, OR FOR INJURY TO PERSONS OR PROPERTY) ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT OR ITS SUBJECT MATTER. TSRI’S AGGREGATE LIABILITY, IF ANY, FOR ALL DAMAGES OF ANY KIND RELATING TO THIS AGREEMENT OR ITS SUBJECT MATTER SHALL NOT EXCEED THE AMOUNT PAID BY LICENSEE TO TSRI UNDER THIS AGREEMENT. THE FOREGOING EXCLUSIONS AND LIMITATIONS SHALL APPLY TO ALL CLAIMS AND ACTIONS OF ANY KIND AND ON ANY THEORY OF LIABILITY, WHETHER BASED ON CONTRACT, TORT (INCLUDING, BUT NOT LIMITED TO NEGLIGENCE OR STRICT LIABILITY), OR ANY OTHER GROUNDS, AND REGARDLESS OF WHETHER EITHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, AND NOTWITHSTANDING ANY FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

11. Confidentiality and Publication.

11.1 Treatment of Confidential Information. The parties agree that during the term of this Agreement, and for a period of five (5) years after this Agreement expires or terminates, a party receiving Confidential Information of the other party will (a) maintain in confidence such Confidential Information to the same extent such party maintains its own proprietary information; (b) not disclose such Confidential Information to any third party without the prior written consent of the other party; and (c) not use such Confidential Information for any purpose except those permitted by this Agreement. TSRI agrees that Licensee and its sublicensees shall be permitted to disclose information that relates to the subject matter claimed in the Licensed Patent Rights in connection with the exercise of the rights licensed hereunder by TSRI to Licensee as long as the disclosure of such information is protected under written obligations of confidentiality which are at least as restrictive as those contained in this Agreement.

11.2 Publications. Licensee agrees that TSRI shall have a right to publish scientific data or results generated by TSRI in accordance with its general policies, and that this Agreement shall not restrict, in any fashion, TSRI’s right to publish.

11.3 Publicity. Except as otherwise provided herein or required by law, no party shall originate any publication, news release or other public announcement, written or oral, whether in the public press, stockholders’ reports, or otherwise, relating to this Agreement or to any sublicense hereunder, or to the performance hereunder or under any such sublicense agreements, without the prior written approval of the other party, which approval shall not be unreasonably withheld. Once material is so approved for publication, either party shall be permitted to re-publish it thereafter without seeking additional consent from the other party. Notwithstanding the foregoing, Licensee may make such disclosure as it deems reasonable in order to comply with law, including the files and regulations of the U.S. Securities and Exchange Commission and of the Nasdaq Global Market or such other market on which the Licensee is then listed. Scientific publications published in accordance with Section 11.2 of this Agreement shall not be construed as publicity governed by this Section 11.3.

12. Term and Termination.

12.1 Term. Unless terminated sooner in accordance with the terms set forth herein, this Agreement, and the licenses granted hereunder, shall expire or terminate upon the expiration of the payment obligations of Licensee as provided in Section 3.9 hereof.

12.2 Termination Upon Mutual Agreement. This Agreement may be terminated by mutual written consent of both parties.

12.3 Termination by TSRI. TSRI may terminate this Agreement as follows:

(a) If Licensee does not make a payment due hereunder and fails to cure such non-payment (including the payment of interest in accordance with Section 14.2) within thirty (30) days after the date of notice in writing of such non-payment by TSRI;

(b) If Licensee defaults in its indemnification and insurance obligations under Section 9;

(c) As provided in Section 6.2;

(d) If Licensee shall become insolvent, shall make an assignment for the benefit of creditors, or shall have a petition in bankruptcy filed for or against it. Such termination shall be effective immediately upon TSRI giving written notice to Licensee;

(e) If an examination by TSRI’s accountant pursuant to Section 7 shows an underreporting or underpayment by Licensee in excess of twenty percent (20%) for any twelve month period, and a subsequent audit shows a similar underreporting of underpayment by Licensee in excess of twenty (20%) or more for any subsequent calendar year;

(f) If Licensee is convicted of a felony, and all rights of appeal with respect thereto have been exhausted, relating to the manufacture, use or sale of Licensed Products, Licensed Services, or Licensed Processes; or

(g) Except as provided in subparagraphs (a)—(f) above, if Licensee defaults in the performance of any obligations under this Agreement and the default has not been remedied within sixty (60) days after the date of notice in writing of such default by TSRI.

12.4 Termination by Licensee. Licensee may terminate this Agreement by giving ninety (90) days advance written notice of termination to TSRI.

12.5 Rights Upon Expiration. Neither party shall have any further rights or obligations upon the expiration of this Agreement upon its regularly scheduled expiration date other than the obligation of Licensee to make any and all reports and payments for the final quarterly period. Provided, however, that upon such expiration, each party shall be required to continue to abide by its non-disclosure obligations as described in Section 11.1 which shall survive shall expiration. The right of TSRI to audit pursuant to Section 7, Licensee’s obligation to indemnify TSRI and maintain insurance as described in Section 9 and Sections 2.6, 2.7, 6.3, 6.4, 6.5, 6.6, 8.3, 8.4, 10, 11.1, 12 and 14 shall also survive the expiration of this Agreement.

12.6 Rights Upon Termination. Notwithstanding any other provision of this Agreement, upon any termination of this Agreement prior to the regularly scheduled expiration date of this Agreement, the licenses granted hereunder shall terminate and revert to TSRI, and all sublicenses granted by Licensee shall also automatically terminate. Except as otherwise provided in Section 12.7 of this Agreement with respect to work-in-progress, upon such termination, Licensee shall have no further right to develop, manufacture or market any Licensed Product or Licensed Service, or to otherwise use any Licensed Patent Rights. Upon any such termination, Licensee shall promptly return all materials, samples, documents, information, and other materials that embody or disclose Licensed Patent Rights; provided, however, that Licensee shall not be obligated to provide TSRI with proprietary information that Licensee can show that it independently developed. Any such termination shall not relieve either party from any obligations accrued to the date of such termination. Upon such termination, each party shall be required to abide by its nondisclosure obligations as described in Section 11.1 which shall survive such termination. The right of TSRI to audit pursuant to Section 7, Licensee’s obligation to indemnify TSRI and maintain insurance as described in Section 9, and Sections 2.6, 2.7, 6.3, 6.4, 6.5, 6.6, 8.3, 8.4, 10, 11.1, 12 and 14 shall also survive the termination of this Agreement.

12.7 Work-in-Progress. Upon any such early termination of the licenses granted hereunder in accordance with this Agreement, Licensee shall be entitled to finish any work-in-progress and to sell any completed inventory of a Licensed Product covered by such licenses which remain on hand as of the date of the termination, so long as Licensee sells such inventory in the normal course of business and at regular selling prices and pays to TSRI the royalties applicable to said subsequent sales in accordance with the terms and conditions as set forth in this Agreement, provided that no such sales shall be permitted after the expiration of six (6) months after the date of termination.

12.8 Final Royalty Report. Upon termination or expiration of this Agreement, Licensee shall submit a final report to TSRI, and any payments due TSRI and unreimbursed patent expenses invoiced by TSRI shall become immediately payable.

13. Assignment; Successors.

13.1 Assignment. This Agreement may not be assigned or otherwise transferred (whether voluntarily, by operation of law or otherwise) by Licensee without the prior written consent of TSRI which shall not be unreasonably withheld; provided however that Licensee may, without such consent, assign this Agreement and its rights and obligations hereunder to an Affiliate or in connection with the transfer or sale of all of its business, or in the event of its merger, consolidation, change in control, or other similar transaction. Any and all other assignments of this Agreement or any rights granted hereunder by Licensee without the prior written consent of TSRI are void.

13.2 Binding Upon Successors and Assigns. Subject to the limitations on assignment herein, this Agreement shall be binding upon and inure to the benefit of any successors in interest and assigns of TSRI and Licensee. Any such successor or assignee of Licensee’s interest shall expressly assume in writing the performance of all the terms and conditions of this Agreement to be performed by Licensee and such written assumption shall be delivered to TSRI as a condition to TSRI’s agreement to consent to any such assignment.

14. General Provisions.

14.1 Independent Contractors. The relationship between TSRI and Licensee is that of independent contractors. TSRI and Licensee are not joint venturers, partners, principal and agent, master and servant, employer or employee, and have no other relationship other than independent contracting parties. TSRI and Licensee shall have no power to bind or obligate each other in any manner, other than as is expressly set forth in this Agreement.

14.2 Late Payments. Except as otherwise provided in Section 7, late payments of any and all payments due hereunder shall be subject to a charge of one and one-half percent (1-1/2%) per month, or two hundred and fifty dollars ($250) whichever is greater.

14.3 Governmental Approvals and Marketing of Licensed Products. Licensee shall be responsible for obtaining all necessary governmental approvals for the development, production, distribution, performance, sale and use of any Licensed Product, Licensed Service and/or Licensed Process, at Licensee’s expense, including, without limitation, any safety studies. Licensee shall have sole responsibility for any warning labels, packaging and instructions as to the use of Licensed Products and for the quality control for any Licensed Products.

14.4 Patent Marking. To the extent required by applicable law, Licensee shall mark all Licensed Products or their containers in accordance with the applicable patent marking laws.

14.5 No Use of Name. The use of the name “The Scripps Research Institute”, “Scripps”, “TSRI” or any variation thereof in connection with the advertising, sale or performance of Licensed Products, Licensed Services, or Licensed Processes is expressly prohibited.

14.6 U.S. Manufacture. To the extent required, Licensee agrees to abide by the Preference for United States Industry as set forth in 37 CFR 401.14 (I).

14.7 Foreign Registration. Licensee agrees to register this Agreement with any foreign governmental agency that requires such registration, and Licensee shall pay all costs and legal fees in connection therewith. In addition, Licensee shall ensure that all foreign laws affecting this Agreement or the sale of Licensed Products, Licensed Services or Licensed Processes are fully satisfied.

14.8 Use of Materials. Licensee agrees that its use of any materials supplied by TSRI shall comply with all applicable statutes, regulations, and guidelines. Licensee agrees not to use any materials supplied by TSRI for research involving human subjects or clinical trials in the United States without complying with 21 CFR 50 and 45 CFR 46. Licensee agrees not to use any materials supplied by TSRI for research involving human subjects or clinical trials outside of the United States without complying with the applicable regulations of the appropriate national control authorities.

14.9 Arbitration. Any controversy or claim arising out of or relating to this Agreement, or the breach thereof, shall be settled by binding confidential arbitration in accordance with the Commercial Arbitration Rules of the American Arbitration Association (“AAA”), and the procedures set forth below. In the event of any inconsistency between the Rules of AAA and the procedures set forth below, the procedures set forth below shall control. Judgment upon the award rendered by the arbitrators may be enforced in any court having jurisdiction thereof.

14.9.1 Location. The location of the arbitration shall be in the County of San Diego, California.

14.9.2 Selection of Arbitrators. The arbitration shall be conducted by a panel of three neutral arbitrators who are independent and disinterested with respect to the parties, this Agreement, and the outcome of the arbitration. Each party shall appoint one neutral arbitrator, and these two arbitrators so selected by the parties shall then select the third arbitrator, and all arbitrators must have substantial experience in mediating or arbitrating cases regarding the same or substantially similar subject matter as the dispute between Licensee and TSRI. If one party has given written notice to the other party as to the identity of the arbitrator appointed by the party, and the party thereafter makes a written demand on the other party to appoint its designated arbitrator within the next thirty (30) days, and the other party fails to appoint its designated arbitrator within thirty (30) days after receiving said written demand, then the arbitrator who has already been designated shall appoint the other two arbitrators.

14.9.3 Discovery. The arbitrators shall decide any disputes and shall control the process concerning these pre-hearing discovery matters. Pursuant to the Rules of AAA, the parties may subpoena witnesses and documents for pre-hearing discovery and/or for presentation at the hearing.

14.9.4 Case Management. Prompt resolution of any dispute is important to both parties; and the parties agree that the arbitration of any dispute shall be conducted expeditiously. The arbitrators are instructed and directed to assume case management initiative and control over

the arbitration process (including scheduling of events, pre-hearing discovery and activities, and the conduct of the hearing), in order to complete the arbitration as expeditiously as is reasonably practical for obtaining a just resolution of the dispute.

14.9.5 Remedies. The arbitrators may grant any legal or equitable remedy or relief that the arbitrators deem just and equitable, to the same extent that remedies or relief could be granted by a state or federal court, provided however, that no punitive damages may be awarded. No court action shall be maintained seeking punitive damages. The decision of any two of the three arbitrators appointed shall be binding upon the parties. Notwithstanding anything to the contrary in this Agreement, prior to or while an arbitration proceeding is pending, either party has the right to seek and obtain injunctive and other equitable relief from a court of competent jurisdiction to enforce the parties’ rights hereunder.

14.9.6 Expenses. The expenses of the arbitration, including the arbitrators’ fees, expert witness fees, and attorney’s fees, may be awarded to the prevailing party, in the discretion of the arbitrators, or may be apportioned between the parties in any manner deemed appropriate by the arbitrators. Unless and until the arbitrators decide that one party is to pay for all (or a share) of such expenses, both parties shall share equally in the payment of the arbitrators’ fees as and when billed by the arbitrators.

14.9.7 Confidentiality. Except as set forth below and as necessary to obtain or enforce a judgment upon any arbitration award, the parties shall keep confidential the fact of the arbitration, the dispute being arbitrated, and the decision of the arbitrators. Notwithstanding the foregoing, the parties may disclose information about the arbitration to persons who have a need to know, such as directors, trustees, management employees, witnesses, experts, investors, attorneys, lenders, insurers, and others who may be directly affected. Additionally, if a party has stock which is publicly traded, the party may make such disclosures as are required by applicable securities laws, but will use commercially reasonable efforts to seek confidential treatment for such disclosure.

14.10 Entire Agreement; Modification. This Agreement and all of the attached Exhibits set forth the entire agreement and understanding between the parties as to the subject matter hereof, and supersedes all prior or contemporaneous agreements or understandings, whether oral or written. There shall be no amendments or modifications to this Agreement, except by a written document that is signed by both parties.

14.11 California Law. This Agreement shall be construed and enforced in accordance with the laws of the State of California without regard to the conflicts of laws principles thereof. Each party hereby irrevocably submits to the exclusive jurisdiction and venue of the Federal and State courts located in San Diego County, California, for any action or proceeding to enforce an arbitration award or as otherwise provided in Section 14.9.5, and waives any right to contest or otherwise object to such jurisdiction or venue.

14.12 Headings. The headings for each article and section in this Agreement have been inserted for convenience of reference only and are not intended to limit or expand on the meaning of the language contained in the particular article or section.

14.13 Severability. Should any one or more of the provisions of this Agreement be held invalid or unenforceable by a court of competent jurisdiction, it shall be considered severed from this Agreement and shall not serve to invalidate the remaining provisions thereof. The parties shall make a good faith effort to replace any invalid or unenforceable provision with a valid and enforceable one such that the objectives contemplated by them when entering this Agreement may be realized.

14.14 No Waiver. Any delay in enforcing a party’s rights under this Agreement or any waiver as to a particular default or other matter shall not constitute a waiver of such party’s rights to the future enforcement of its rights under this Agreement, excepting only as to an express written and signed waiver as to a particular matter for a particular period of time.

14.15 Name. Whenever there has been an assignment or a sublicense by Licensee as permitted by this Agreement, the term “Licensee” as used in this Agreement shall also include and refer to, if appropriate, such assignee or sublicensee.

14.16 Attorneys’ Fees. In the event of a dispute between the parties hereto or in the event of any default hereunder, the party prevailing in the resolution of any such dispute or default shall be entitled to recover its reasonable attorneys’ fees and other costs incurred in connection with resolving such dispute or default.

14.17 Notices. Any notices required by this Agreement shall be in writing, shall specifically refer to this Agreement and shall be sent by registered or certified airmail, postage prepaid, or by telefax, telex or cable, charges prepaid, or by overnight courier, postage prepaid and shall be forwarded to the respective addresses set forth below unless subsequently changed by written notice to the other party:

For TSRI:	The Scripps Research Institute
	10550 North Torrey Pines Road, TPC-9
	La Jolla, California 92037
	Attention: Director, Technology Development
	Fax No.: (858) 784-9910
with a copy to:	The Scripps Research Institute
	10550 North Torrey Pines Road, TPC-8
	La Jolla, California 92037
	Attention: General Counsel
	Fax No.: (858) 784-9399
For Licensee:	Repligen Corporation
	41 Seyon Street, Building #1
	Waltham, MA 02453
	Attention: Chief Executive Officer
	Fax No.: (781) 250-0115
with a copy to:	Goodwin Procter LLP
	53 State Street

Boston, MA 02109

Attention: Robert E. Puopolo

Fax No.: (617) 523-1231

Notices shall be deemed delivered upon the earlier of (a) when received; (b) three (3) days after deposit into the U.S. Mail; (c) the date notice is sent via telefax, telex or cable; or (d) the day immediately following delivery to overnight courier (except Sunday and holidays).

14.18 Compliance with U.S. Laws. Nothing contained in this Agreement shall require or permit TSRI or Licensee to do any act inconsistent with the requirements of any United States law, regulation or executive order as the same may be in effect from time to time.

IN WITNESS WHEREOF, the parties have executed this Agreement by their duly authorized representatives as of the date set forth above.

TSRI:		LICENSEE:
THE SCRIPPS RESEARCH INSTITUTE		REPLIGEN CORPORATION
By:	signature illegible	By:	/s/Walter C. Herlihy
Title:	Senior Vice President Business and Scientific Services	Title:	President & CEO

EX-23.1

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statements (Form S-3 No.’s 333-106109, 333-62796, 333-30383, 333-57951, 333-76005, 333-79611, 333-95641, 333-31728, 333-35056, and 333-36280 and Registration Statement Form S-8 No. 333-89140) of Repligen Corporation and in the related Prospectuses of our report dated June 6, 2007, with respect to the financial statements of Repligen Corporation, Repligen Corporation management’s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of Repligen Corporation, included in this Annual Report (Form 10-K) for the year ended March 31, 2007.

/s/ Ernst & Young LLP

Boston, Massachusetts

June 6, 2007

EX-31.1

Exhibit 31.1

CERTIFICATION

I, Walter Herlihy, certify that:

1. I have reviewed this Annual Report on Form 10-K of Repligen Corporation;

2. Based on my knowledge, this Annual Report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this Annual Report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officers and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide a reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an Annual Report ) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officers and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s board of directors (or persons performing the equivalent function):

(a) All significant deficiencies and material weaknesses in the design or operation of internal controls over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: June 8, 2007
	/s/ Walter C. Herlihy
	Walter C. Herlihy
	Chief Executive Officer and President
	(Principal executive officer)

EX-31.2

Exhibit 31.2

CERTIFICATION

I, Daniel W. Muehl, certify that:

1. I have reviewed this Annual Report on Form 10-K of Repligen Corporation;

2. Based on my knowledge, this Annual Report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this Annual Report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officers and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide a reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an Annual Report ) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officers and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s board of directors (or persons performing the equivalent function):

(a) All significant deficiencies and material weaknesses in the design or operation of internal controls over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: June 8, 2007
	/s/ Daniel W. Muehl
	Daniel W. Muehl
	Chief Financial Officer
	(Principal accounting and financial officer)

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Repligen Corporation (the “Company”) on Form 10-K for the period ending March 31, 2007 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned officers of the Company hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, to my knowledge, that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) as applicable of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

June 8, 2007

/s/ Walter C. Herlihy

Walter C. Herlihy

Chief Executive Officer and President (Principal executive officer)

/s/ Daniel W. Muehl

Daniel W. Muehl

Chief Financial Officer (Principal accounting and financial officer)