Repligen shareholders approve charter amendment allowing board to amend bylaws at 2023 annual meeting

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year. As described below in Item 5.07 of this Current Report on Form 8-K and in Repligen Corporation’s (the “Company”) proxy statement filed with the Securities and Exchange Commission under Section 14(a) of the Securities Exchange Act, as amended, on April 11, 2023 (the “Proxy Statement”), on May 18, 2023, the Company’s shareholders voted at the Company’s 2023 annual meeting of shareholders (the “Annual Meeting”) to, among other things, approve an amendment (the “Charter Amendment”) to the Company’s Certificate of Incorporation to permit the Board of Directors of the Company (the “Board”) to adopt, amend or repeal the Company’s By-laws.

Proposal 1 - Election of the Board of Directors Nicolas M. Barthelemy, Karen A. Dawes, Carrie Eglinton Manner, Tony J. Hunt, Rohin Mhatre, Ph.D., Glenn P. Muir, Konstantin Konstantinov, Ph.D. and Martin Madaus, D.V.M., Ph.D. were duly elected to the Board. The results of the election were as follows: NOMINEE FOR AGAINST ABSTAIN BROKER NON-VOTES Nicolas M. Barthelemy 46,619,756 2,954,456 37,128 2,990,083 Karen A. Dawes 44,258,984 5,315,967 36,389 2,990,083 Carrie Eglinton Manner 49,411,646 163,031 36,663 2,990,083 Tony J. Hunt 49,421,145 153,400 36,795 2,990,083 Rohin Mhatre, Ph.D. 48,929,182 641,737 40,421 2,990,083 Glenn P. Muir 48,828,381 745,628 37,331 2,990,083 Konstantin Konstantinov, Ph.D. 47,615,575 1,958,323 37,442 2,990,083 Martin Madaus, D.V.M., Ph.D. 48,627,119 946,461 37,760 2,990,083

Proposal 6 – Approve the Ratification of the Amendment and Restatement of the By-laws The ratification of the amendment and restatement of the By-laws adopted by the Board on January 27, 2021 to implement shareholder proxy access was ratified. The results of the ratification were as follows: FOR AGAINST ABSTAIN BROKER NON-VOTES NUMBER 49,551,765 19,487 40,088 2,990,083

Proposal 3 - Advisory Vote on Compensation of the Named Executive Officers The compensation paid to the Company's named executive officers was approved on an advisory basis. The results of the vote were as follows: FOR AGAINST ABSTAIN BROKER NON-VOTES NUMBER 48,195,853 1,375,453 40,034 2,990,083

Proposal 5 - Approve the Charter Amendment The amendment to the Company's Certificate of Incorporation to permit the Board to adopt, amend or repeal the By-laws was approved. The results of the vote were as follows: FOR AGAINST ABSTAIN BROKER NON-VOTES NUMBER 42,247,296 6,615,716 748,328 2,990,083

Proposal 2 - Ratify the Appointment of Independent Registered Public Accounting Firm The appointment of Ernst & Young LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2023 was ratified. The results of the ratification were as follows: FOR AGAINST ABSTAIN BROKER NON-VOTES NUMBER 51,821,932 754,809 24,682 0

Proposal 4 – Advisory Vote on Frequency of Future Advisory Votes on the Compensation of Named Executive Officers The frequency of future advisory votes on the compensation of the Company's named executive officers was approved on advisory basis. The results of the vote were as follows: 1 Year 2 Years 3 Years ABSTAIN BROKER NON-VOTES NUMBER 49,248,032 32,822 287,871 42,615 2,990,083