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): June 29, 2020

REPLIGEN CORPORATION

(Exact name of registrant as specified in its 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 June 29, 2020, Repligen Corporation (the “Company”) issued a press release announcing that the Company acquired Engineered Molding Technologies LLC (the “EMT”) pursuant to a Membership Interest Purchase Agreement (the “Purchase Agreement”), dated as of June 26, 2020, by and among the Company, EMT and Michael Pandori, an individual, and Todd Etesse, an individual. A copy of the press release is attached to this Current Report on Form 8-K as Exhibit 99.1 and is incorporated herein by reference.

(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 Announces Agreement to Acquire Engineered Molding Technology

Expands Single-Use Portfolio with Expertise in Silicone Molding and Tubing

WALTHAM, MA – June 29, 2020 – Repligen Corporation (NASDAQ:RGEN), a life sciences company focused on bioprocessing technology leadership, today announced that it has entered into an agreement to acquire Albany, New York based Engineered Molding Technology (“EMT”), an innovator and manufacturer of single-use silicone assemblies and components used in the manufacturing of biologic drugs. EMT’s standard and custom molded and over-molded connectors and silicone tubing products are key components in single-use filtration and chromatography systems.

Tony J. Hunt, President and CEO of Repligen, said, “The acquisition of EMT expands our line of single-use ProConnex^®^ flow paths, streamlines our supply chain for ATF, and gives us more flexibility as we scale and expand our single-use and systems portfolios.” He continued, “The EMT portfolio also enables us to offer bioprocessing customers faster lead-times on single-use flow path solutions and to provide biopharmaceutical and CDMO customers with a more fully integrated and complete product offering in Filtration and Chromatography.”

Michael Pandori, co-founder of Engineered Molding Technology, said, “Over the last ten years, EMT has grown to become a key player in the supply of extruded and molded silicone products into the bioprocessing industry. We are at a transition point now where it makes sense to join forces with Repligen, who has an impressive history of scaling companies to the next level. For EMT, this means taking our products global, expanding our commercial footprint and integrating select EMT technologies into Repligen product lines while continuing to innovate.”

The proposed acquisition is expected to close during Repligen’s third quarter of 2020. Financial details were not disclosed. Perella Weinberg Partners LP is acting as financial advisor and Goodwin Procter LLP is serving as legal counsel to Repligen.

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

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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.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the federal securities laws. Investors are cautioned that statements in thispress release which are not strictly historical statements including, without limitation, express or implied statements or guidance regarding the expected results of the proposed acquisition of EMT on Repligen’s future financial performance,including the accretive nature and the timing of the accretive nature of the acquisition, expected synergies following the acquisition of EMT, customer adoption of EMT’s products, the expected expansion of Repligen’s product lines, thetiming of the closing of the acquisition and other 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, without limitation, risks associatedwith: the risk that the proposed acquisition may not be completed in a timely manner, or at all; the occurrence of any event, change or other circumstance that could give rise to the termination of the acquisition; our ability to integrateEMT’s business and personnel and to achieve expected synergies; our ability to maintain or expand EMT’s historical sales; our ability to accurately forecast the acquisition, related restructuring costs and allocation of the purchase price,goodwill and other intangibles acquisition related and other asset adjustments; and other risks detailed in Repligen’s most recent Annual Report on Form 10-K on file with the Securities and ExchangeCommission and the other reports that Repligen periodically files with the Securities and Exchange Commission. Actual results may differ materially from those Repligen contemplated by these forward-looking statements. These forward lookingstatements reflect management’s current views and Repligen does not undertake to update any of these forward-looking statements to reflect a change in its views or events or circumstances that occur after the date hereof except as required bylaw.

Repligen Contact:

Sondra S. Newman

Global Head of Investor Relations

(781) 419-1881

investors@repligen.com

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