Repligen (RGEN)

6. 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, 2005 and March 31, 2004.

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 in the Company’s balance sheet.

Obligations under noncancelable operating leases and capital equipment leases, including the facility lease discussed above as of March 31, 2005 are approximately as follows:

Rent expense charged to operations under leases was approximately $389,000, $389,000, and $372,000, for the years ended March 31, 2005, 2004 and 2003, respectively.

F-14

REPLIGEN CORPORATION

NOTES TO FINANCIAL STATEMENTS—(Continued)

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 $55,000, $298,000, and $56,000, for the years ended March 31, 2005, 2004 and 2003, 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 $140,000 associated with this agreement for the year ended March 31, 2006. 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.