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 6, 2023

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.  ☐

Nomination of Martin Madaus, Ph.D.

On February 6, 2023, based on the recommendation of the Nominating and Corporate Governance Committee of the Board of Directors (the “Board”) of Repligen Corporation (the “Company”), the Board elected Martin Madaus, Ph.D. to the Board, effective February 6, 2023 (the “Effective Date”). Dr. Madaus was also appointed to the Nominating and Corporate Governance Committee of the Board, effective as of the Effective Date.

In connection with Dr. Madaus’ 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, Dr. Madaus is entitled to 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, Dr. Madaus was granted an option to purchase shares of the Company’s common stock having an aggregate value of $170,000 (the “Initial Board Option”). The Initial Board Option vests equally over a three-year period. 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 Corporation’s common 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 both stock options and restricted stock units.

Additionally, under the Director Compensation Policy, on the Effective Date, Dr. Madaus was granted (1) an option to purchase shares of the Company’s common stock having an aggregate value of $21,250 and (2) restricted stock units having an aggregate value of $21,250 (together, the “Pro-Rata Award”), equal to the annual equity grant for non-employee directors reelected to the Board. The Pro-Rata Award fully vests on the date of the next annual meeting of shareholders subject to Dr. Madaus’s continued service on the Board as of such date. The stock options granted as part of the Pro-Rata Award have a term of ten years, subject to early termination in the event of death, removal or resignation from the Board. The stock options granted as part of the Pro-Rata Award have an exercise price equal to the closing price of the Company’s common stock on the Effective Date.

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

On February 9, 2023, the Company issued a press release announcing Dr. Madaus’ 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 Martin D. Madaus to Board of Directors

WALTHAM, MA – February 9, 2023 – Repligen Corporation (NASDAQ:RGEN) today announced the appointment to its Board of Directors of life sciences tools industry leader Martin D. Madaus.

Dr. Madaus brings to the Repligen board over 25 years of industry experience, including five years as Chairman, President and Chief Executive Officer of Millipore Corporation, where he was integral to the company’s transformation into a life science leader, and its acquisition by Merck KGaA in 2010. He is an active board leader, currently serving two public companies; as Lead Director for precision health technology company Quanterix Corporation and as Board member for mass cytometry player Standard BioTools, Inc. (previously Fluidigm Corporation).

Karen A. Dawes, Chairperson of the Board of Directors for Repligen, said, “We are thrilled to welcome Dr. Madaus to the Repligen board, as the company continues to drive innovation in bioprocessing and expand into new markets. Martin’s exceptional career demonstrates his success as a leader and his aptitude for guiding growth. We are certain to benefit from his involvement as we continue to set new standards in bioprocessing and scale our product portfolio.”

Tony J. Hunt, President and Chief Executive Officer said, “I’m excited for this opportunity to work more closely with Martin. He is a terrific addition to the Board, bringing extensive bioprocessing and biopharmaceutical industry experience, especially in the areas of strategy, M&A and commercial. Martin will be a key asset to the Board as we move forward on our journey of transforming bioprocessing through cutting edge innovation.”

Dr. Madaus’ executive profile includes his aforementioned leadership of Millipore Corporation, in addition to his earlier role as President and Chief Executive Officer, N.A., with Roche Diagnostics Corp., and his more recent position as Chairman and Chief Executive Officer at Ortho Clinical Diagnostics. He is currently a senior operating executive at The Carlyle Group.

In addition to his current public company board positions, Dr. Madaus currently leads the boards of three private companies—Unchained Labs, Emulate, Inc. and UltiVue Inc. Dr. Madaus previously served on the Board at Covidien, Ltd. and Mettler-Toledo International Inc.

Dr. Madaus began his career as a veterinarian, before joining Boehringer Mannheim Corporation, where he worked in sales and marketing roles from 1989-1996, until his move into general management coincident with the company’s acquisition by Roche Holdings, AG. He holds a D.V.M. from the University of Munich and a Ph.D. in veterinary medicine from the University of Veterinary Medicine Hannover in Germany.

About Repligen Corporation Repligen Corporation is a global company that develops and commercializes highly innovative bioprocessing technologies and systems that enable 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 focus areas are Filtration, Chromatography, Process Analytics, Fluid Management and Proteins. Our corporate headquarters are located in Waltham, Massachusetts, with additional administrative and manufacturing operations worldwide. The majority of our manufacturing sites are located within the U.S. (California, Massachusetts, New Hampshire, New Jersey and New York), and we also have sites in Estonia, France, Germany, Ireland, the Netherlands and Sweden. For more information about the company, including Repligen news releases, see our website at http://www.repligen.com. Follow us on LinkedIn and Twitter.

This press release may contain forward-looking statements within the meaning of the federal securities laws. Investors are cautioned that statements inthis 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 differ materially 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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