8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT PURSUANT

TO SECTION 13 OR 15(D) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported) December 12, 2007

REPLIGEN CORPORATION

(Exact Name of Registrant as Specified in Its Charter)

DELAWARE

(State or Other Jurisdiction of Incorporation)

0-14656	04-2729386
(Commission File Number)	(IRS Employer Identification No.)

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

(781) 250-0111

(Registrant’s Telephone Number, Including Area Code)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions ( see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

INFORMATION TO BE INCLUDED IN THE REPORT

Item 5.02. Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On December 12, 2007, Earl Henry, M.D. was elected to the Board of Directors (the “Board”) of Repligen Corporation (the “Company”). Dr. Henry is currently Senior Vice President, Medical Affairs for inVentive Clinical Solutions, a premier provider of clinical outsourcing solutions.

Dr. Henry will receive the customary compensation paid to the Company’s non-employee directors. Each non-employee director receives $5,000 per quarter and $1,500 plus expenses for each Board meeting they attend. Under the 2001 Repligen Corporation Stock Plan, each newly-elected, non-employee director who joins the Board is entitled to receive an option to purchase 24,000 shares of Common Stock on the date he or she joins the Board (an “Initial Board Option”). These Initial Board Options vest equally over a three-year period from the date of grant. In addition, each non-employee director is granted an option to purchase 15,000 shares of Common Stock (the “Annual Board Options” and together with the Initial Board Options, the “Board Options”) at the time of each annual stockholder meeting. These options vest in full on the first anniversary of the date of the grant, provided such person is still a director on such anniversary. Board Options have a term of ten years, subject to early termination in the event of death, removal or resignation from the Board. No director would be entitled to receive Board Options covering more than an aggregate of 150,000 shares of Common Stock, excluding expired unexercised options. All of these stock options will have an exercise price equal to the fair market value of the stock on the date the stock option is granted.

There are no arrangements or understandings between Dr. Henry and any other persons pursuant to which Dr. Henry was selected as a director. There have been no transactions since the beginning of the Company’s last fiscal year, or any currently proposed transaction, in which the Company was or is to be a participant, in which the amount involved exceeds $120,000, and in which Dr. Henry had, or will have, a direct or indirect material interest.

The Company has issued a press release announcing Dr. Henry’s election to the Board and has attached a copy of such press release as Exhibit 99.1 hereto.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

Exhibit No.	Description
99.1	Press Release, dated December 13, 2007

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

REPLIGEN CORPORATION

Dated: December 13, 2007

By:  /s/  Walter C. Herlihy                            

        Walter C. Herlihy

        President and Chief Executive Officer

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press Release, dated December 13, 2007

EX-99.1

Exhibit 99.1

RepliGen   FOR IMMEDIATE RELEASE Repligen Corporation 41 Seyon Street Building #1, Suite 100 Waltham, Massachusetts 02453 Telephone: 781-250-0111 Telefax: 781-250-0115

CONTACT:

Walter C. Herlihy, Ph.D. President and Chief Executive Officer (781) 250-0111, ext. 2000 Laura L. Whitehouse Vice President, Market Development (781) 250-0111, ext. 2306

Repligen Elects Earl Henry, M.D. to the Board of Directors

WALTHAM, MA – December 13, 2007 – Repligen Corporation (NASDAQ: RGEN) announced today that Dr. Earl Webb Henry, M.D. has been elected to its Board of Directors. Dr. Henry is a highly experienced executive with worldwide clinical and regulatory expertise in the development of therapeutics for disorders affecting the Central Nervous System.

“We are very pleased to welcome an executive with Earl’s industry knowledge and drug development expertise to our Board,” stated Walter C. Herlihy, President and Chief Executive Officer of Repligen Corporation. “Earl’s strategic guidance and relationships within the medical community will be an invaluable asset to the Company as we develop and expand our emerging CNS pipeline.”

Dr. Henry has held numerous executive level positions including Senior Vice President and Head, Worldwide Clinical Research and Regulatory Affairs for Cephalon, Inc., Vice President, Clinical Research for Guilford Pharmaceuticals Inc., Global Head of Central Nervous System Therapeutic Area for Sandoz Research Institute and Senior Associate Director of Clinical Research for Pfizer. Dr. Henry has participated in the development and approval of numerous neurologic and psychiatric drugs. Dr. Henry earned his medical degree from the University of Chicago and completed his residence and fellowship at Harvard Medical School in neurology and neuropathology. Dr. Henry is currently Senior Vice President, Medical Affairs for inVentiv Clinical Solutions, a premier provider of clinical outsourcing solutions.

About Repligen Corporation

Repligen Corporation is a biopharmaceutical company focused on the development of novel therapeutics for diseases that affect the central nervous system. In addition, we are the world’s leading supplier of recombinant Protein A, the sales of which partially fund the advancement of our development pipeline while supporting our financial stability. Repligen’s corporate headquarters are located at 41 Seyon Street, Building #1, Suite 100, Waltham, MA 02453. Additional information may be requested from www.repligen.com.

This press release contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The forward-looking statements in this release do not constitute guarantees of future performance. Investors are cautioned that statements in this press release which are not strictly historical statements, including, without limitation, statements regarding current or future financial performance and position, management’s strategy, plans and objectives for future operations, plans and objectives for product development, plans and objectives for present and future clinical trials and results of such trials, plans and objectives for regulatory approval, litigation, intellectual property, product development, manufacturing plans and performance such as the anticipated growth in the monoclonal antibody market and our other target markets and projected growth in product sales, 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, risks associated with: the success of current and future collaborative relationships, the market acceptance of our products, our ability to compete with larger, better financed pharmaceutical and biotechnology companies, new approaches to the treatment of our targeted diseases, our expectation of incurring continued losses, our uncertainty of product revenues and profits, our ability to generate future revenues, our ability to raise additional capital to continue our drug development programs, the success of our clinical trials, our ability to develop and commercialize products, our ability to obtain required regulatory approvals, our compliance with all Food and Drug Administration regulations, our ability to obtain, maintain and protect intellectual property rights for our products, the risk of litigation regarding our intellectual property rights, our limited sales and manufacturing capabilities, our dependence on third-party manufacturers and value added resellers, our ability to hire and retain skilled personnel, our volatile stock price, and other risks detailed in Repligen’s filings with the Securities and Exchange Commission. Repligen assumes no obligation to update any forward-looking information contained in this press release or with respect to the announcements described herein.