Larimar Therapeutics, Inc.

CERTIFICATE OF AMENDMENT OF

NINTH AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF

LARIMAR THERAPEUTICS, INC.

Larimar Therapeutics, Inc., a Delaware corporation (the “Corporation”), hereby certifies as follows:

1. The Board of Directors of the Corporation duly adopted resolutions declaring advisable the amendment of the Ninth Amended and Restated Certificate of Incorporation, as amended, of the Corporation (the “Certificate of Incorporation”) set forth in paragraph 3 of this Certificate of Amendment.

2. The amendment to the Certificate of Incorporation set forth in paragraph 3 of this Certificate of Amendment was duly adopted in accordance with the provisions of Section 242 of the General Corporation Law of the State of Delaware (the “DGCL”).

3. The Certificate of Incorporation is hereby amended by replacing the first paragraph of Article IV in its entirety to read as follows:

“The total number of shares of capital stock which the Corporation shall have authority to issue is 220,000,000, of which (i) 215,000,000 shares shall be a class designated as common stock, par value $0.001 per share (the “Common Stock”), and (ii) 5,000,000 shares shall be a class designated as undesignated preferred stock, par value $0.001 per share (the “Undesignated Preferred Stock”).”

IN WITNESS WHEREOF, this Certificate of Amendment has been executed by a duly authorized officer of the Corporation on this th day of , 2026.

Larimar Therapeutics, Inc.

By:

Name: Carole S. Ben-Maimon, M.D.

Title: President and Chief Executive Officer

Larimar Therapeutics logo OTE Your vote matters – here’s how to vote! You may vote online or by phone instead of mailing this card. Online Go to www.envisionreports.com/LRMR or scan the QR code — login details are located in the shaded bar below. Phone Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada Save paper, time and money! Sign up for electronic delivery at www.envisionreports.com/LRMR Using a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. 2026 Annual Meeting Proxy Card q IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. A Proposals — The Board of Directors recommend a vote FOR all the nominees listed, FOR Proposals 2,4,5 and 6 for 1 YEARS on Proposal 3. 1. Election of Class III Directors for a Three-Year Term Expiring in 2029 For Withhold For Withhold For Withhold 01 - Frank Thomas 02 - Carole S. Ben-Maimon, M.D. 03 - Joseph Truitt 2. Approval, on an Advisory Basis, of the Compensation of our Named Executive Officers. 4. Ratification of Appointment of PricewaterhouseCoopers LLP as our Independent Registered Public Accounting Firm for the 2026 Fiscal Year. 6. Approval of an Adjournment of the Annual Meeting to the Extent There are Insufficient Votes at the Annual Meeting to Approve Proposal 5. For Against Abstain 3. Approval, on an Advisory Basis, of the Preferred Frequency of Future Advisory Votes on the Compensation of our Named Executive Officers. 5. Approval of an Amendment to our Ninth Amended and Restated Certificate of Incorporation, as Amended, to Increase the Number of Authorized Shares of our Common Stock from 115,000,000 to 215,000,000. 1 YR 2 YRS 3 YRS Abstain For Against Abstain B Authorized Signatures — This section must be completed for your vote to count. Please date and sign below. Please sign exactly as name(s) appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, corporate officer, trustee, guardian, or custodian, please give full title. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. / / 1 U P X 049RTE +

The 2026 Annual Meeting of Stockholders of Larimar Therapeutics, Inc. will be held on Tuesday, May 19, 2026, at 8:00 A.M. Eastern time, virtually via live webcast at meetnow.global/MWXPCMG. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Important notice regarding the Internet availability of proxy materials for the Annual Meeting of Stockholders. The material is available at: www.envisionreports.com/LRMR Small steps make an impact. Help the environment by consenting to receive electronic delivery, sign up at www.envisionreports.com/LRMR IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. Larimar Therapeutics, Inc. Notice of 2026 Annual Meeting of Stockholders Proxy Solicited by Board of Directors for Annual Meeting — May 19, 2026 Carole S. Ben-Maimon, M.D.; Michael Celano or either of them, each with the power of substitution, are hereby authorized to represent and vote the shares of the undersigned, with all the powers which the undersigned would possess if personally present, at the Annual Meeting of Stockholders of Larimar Therapeutics, Inc. to be held on May 19, 2026 or at any postponement or adjournment thereof. Shares represented by this proxy will be voted as instructed by the undersigned. If no such directions are indicated, the Proxies will have authority to vote FOR the nominees listed, FOR Proposals 2, 4, 5 and 6 and for 1 YEAR on Proposal 3. In their discretion, the Proxies are authorized to vote upon such other business as may properly come before the meeting. (Items to be voted appear on reverse side) C Non-Voting Items Change of Address — Please print new address below. Comments — Please print your comments below. +