FIXX Homology Medicines Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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SCHEDULE 14A INFORMATION

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Homology Medicines, Inc.

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Your Vote Counts! HOMOLOGY MEDICINES, INC. 2023 Annual Meeting Vote by June 13, 2023 11:59 PM ET HOMOLOGY MEDICINES, INC. ONE PATRIOTS PARK BEDFORD, MA 01730 V15880-P88541 You invested in HOMOLOGY MEDICINES, INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy materials for the stockholder meeting to be held on June 14, 2023. Get informed before you vote View the Notice and Proxy Statement and Form 10-K online OR you can receive a free paper or email copy of the material(s) upon request prior to May 31, 2023. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Vote Virtually at the Meeting* Point your camera here and June 14, 2023 8:30 AM EDT vote without entering a control number Virtually at: www.virtualshareholdermeeting.com/FIXX2023 *Please check the meeting materials for any special requirements for meeting attendance. V1.2

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Voting Items Board Recommends 1. Election of Class II Directors to serve until the 2026 Annual Meeting of Stockholders, and until their respective successors shall have been duly elected and qualified. Nominees: For 01) Steven Gillis, Ph.D. 02) Albert Seymour, Ph.D. 2. Ratification of the appointment of Deloitte & Touche LLP as our independent registered public accounting firm for the For fiscal year ending December 31, 2023. NOTE: To transact such other business as may properly come before the Annual Meeting or any continuation, postponement, or adjournment of the Annual Meeting. Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Delivery Settings”. V15881-P88541