UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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): February 26, 2020

REPLIGEN CORPORATION

(Exact name of registrant as specified in charter)

41 Seyon Street, Bldg. 1, Suite 100, Waltham, MA 02453

(Address of Principal Executive Offices) (Zip Code)

(781) 250-0111

(Registrant’s telephone number, including area code)

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):

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

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company  ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

On February 26, 2020, based on the recommendation of the Nominating and Corporate Governance Committee, the Board of Directors (the “Board”) of Repligen Corporation (the “Company”), elected Rohin Mhatre to the Board, effective March 1, 2020 (the “Effective Date”). Mr. Mhatre was also appointed to the Compensation Committee of the Board, effective as of the Effective Date.

In connection with Mr. Mhatre’s election to the Board, the number of directors constituting the Board has been increased from seven to eight.

In connection with his election to the Board, Mr. Mhatre will receive cash and equity compensation pursuant to the Company’s Amended and Restated Non-Employee Directors’ Compensation Policy (the “Director Compensation Policy”). Pursuant to the terms of the Director Compensation Policy, on the Effective Date Mr. Mhatre will receive an option to purchase shares of the Company’s common stock having an aggregate value of $150,000 (the “Initial Board Option”). The Initial Board Option vests equally over a three-year period from the Effective Date. The Initial Board Option has a term of ten years, subject to early termination in the event of death, removal or resignation from the Board. The Initial Board Option has an exercise price equal to the closing price of the stock on the Effective Date. In addition, under the Director Compensation Policy, each non-employee director receives an annual retainer for service on the Board and committees of the Board, and each non-employee director reelected to the Board by the stockholders is awarded annually restricted stock units.

There are no arrangements or understandings between Mr. Mhatre and any other persons pursuant to which Mr. Mhatre 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 Mr. Mhatre had, or will have, a direct or indirect material interest.

On February 27, 2020, the Company issued a press release announcing Mr. Mhatre’s election to the Board and has attached a copy of such press release as Exhibit 99.1 hereto.

(d) Exhibits.

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.

EX-99.1

Exhibit 99.1

Repligen Appoints Rohin Mhatre, Ph.D. to Board of Directors

WALTHAM, MA – February 27, 2020 – Repligen Corporation (NASDAQ:RGEN) today announced the appointment of life sciences industry executive Rohin Mhatre, Ph.D., to its Board of Directors. Dr. Mhatre brings to the director role over 25 years of relevant experience, which includes his current position as Senior Vice President, Product and Technology Development for Biogen Inc. (NASDAQ:BIIB), a leading multinational biopharmaceutical company. Dr. Mhatre leads a cross-functional department responsible for product and process development, process analytics and small-scale manufacturing. Most recently, he has also led the Engineering and Manufacturing Science departments. Throughout his career, he has evaluated and implemented cutting-edge production platforms and process analytical tools for a diverse array of therapeutics, including monoclonal antibodies, gene therapies and oligonucleotides, as well as small molecules.

“We are delighted to welcome Dr. Mhatre to our board,” said Karen A. Dawes, chairperson of the board of Repligen. “The relevance of Rohin’s experience to Repligen is clear. His skillsets and his passion for innovation underscore his success in driving progress in biopharmaceutical manufacturing, and we expect he will be a tremendous asset to the company.”

Tony J. Hunt, President and Chief Executive Officer said, “Rohin understands first-hand the drivers to improve manufacturing efficiency and yield, as biopharmaceutical manufacturing operations move towards flexible, single-use solutions and the drug pipeline diversifies beyond monoclonal antibodies. This will help us shape the future strategic direction for Repligen as we expand our products and applications.”

Dr. Mhatre joined Biogen Inc. in 1996 and has held numerous roles of increasing responsibility leading to his current position of Senior Vice President, Product and Technology Development. Dr. Mhatre’s previous roles with Biogen include Vice President of Biopharmaceutical Development, where he led a 300-member team with responsibility for cell line, cell culture, purification, formulation and device development. Earlier in his career with Biogen, he was focused on building out analytical development and technical services, and prior to Biogen, he led the purification and applications group at Applied Biosystems (formerly Perseptive Biosystems). He received a Ph.D. in chemistry from Northeastern University.

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About Repligen Corporation

Repligen Corporation is a global life sciences company that develops and commercializes highly innovative bioprocessing technologies and systems that increase efficiencies in the process of manufacturing biological drugs. We are inspiring advances in bioprocessing for the customers we serve; primarily biopharmaceutical drug developers and contract development and manufacturing organizations (CDMOs) worldwide. Our corporate headquarters are located in Waltham, MA (USA), and we have additional administrative and manufacturing operations in Marlborough, MA; Bridgewater, NJ; Rancho Dominguez, CA; Lund, Sweden; Breda, The Netherlands and Ravensburg, Germany.

This press release may contain forward-looking statements within the meaning of the federal securities laws. Investors arecautioned that statements in this press release which are not strictly historical statements including, without limitation, statements identified by words like “believe,” “expect,” “may,” “will,”“should,” “seek,” or “could” and similar expressions, constitute forward-looking statements. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differmaterially from those anticipated, including risks discussed from time to time in our filings with the Securities and Exchange Commission. We expressly disclaim any responsibility to update any forward-looking statements, except as required by law.

Repligen Contact:

Sondra S. Newman

Global Head of Investor Relations

(781) 419-1881

investors@repligen.com

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