X0306 4 2023-02-23 0 0001661998 Homology Medicines, Inc. FIXX 0001735324 Seymour Albert C/O HOMOLOGY MEDICINES, INC. ONE PATRIOTS PARK BEDFORD MA 01730 1 1 0 0 See Remarks Employee Stock Option (Right to Buy) 1.60 2023-02-23 4 A 0 632000 0.00 A 2033-02-23 Common Stock 632000 632000 D Restricted Stock Units 2023-02-23 4 A 0 105000 0.00 A Common Stock 105000 105000 D The option vests in 48 substantially equal monthly installments upon the Reporting Person's completion of each full month of service following January 1, 2023. Each restricted stock unit represents a contingent right to receive one share of Issuer common stock. The restricted stock units have no expiration date. The restricted stock units will vest and settle as to one third of the restricted stock units on each of the first three anniversaries of January 1, 2023 so that such RSUs will become fully vested on January 1, 2026. President and Chief Executive Officer /s/ Paul Alloway, Attorney-in-Fact for Albert Seymour 2023-02-27