X0306 4 2022-08-04 0 0001720580 Adicet Bio, Inc. ACET 0001340875 Schor Chen C/O ADICET BIO, INC. 200 BERKELEY STREET, 19TH FLOOR BOSTON MA 02116 1 1 0 0 President & CEO Common Stock 2022-07-06 5 G 0 E 53424 0.00 D 96000 D Common Stock 2022-07-06 5 G 0 E 53424 0.00 A 143260 I See Footnote Common Stock 2022-08-04 4 A 0 48000 0.00 A 144000 D Common Stock 2022-08-04 4 F 0 21288 18.25 D 122712 D Common Stock 74841 I See Footnote Represents the transfer of shares held by the Reporting Person to The C. Schor IRRV Trust for no consideration. Represents shares held directly by The C. Schor IRRV Trust, an irrevocable family trust having an independent trustee. The Reporting Person was issued 240,000 Restricted Stock Units ("RSUs") on October 1, 2021, as previously reported on a Form 4 filed by the Reporting Person on October 5, 2021. Each RSU represents a contingent right to receive one share of common stock. A total of 96,000 of the RSUs shall vest in two (2) annual installments of 20% of the shares vesting, with the first tranche vesting on October 1, 2022 and the second tranche vesting on October 1, 2023. A total of 144,000 of the RSUs shall vest upon achievements of specific milestones outlined in the Reporting Person's Restricted Stock Unit Agreement. On August 4, 2022, upon the occurrence of the third performance milestone, 48,000 of the RSUs vested. The RSUs may be settled only by delivering shares of common stock, and thus, the grant is being reported in Table I as allowed per SEC guidance. Represents shares held directly by The I. Schor IRRV Trust, an irrevocable family trust having an independent trustee. The Reporting Person's Form 4s filed on October 5, 2021, January 11, 2022, February 1, 2022 and February 16, 2022 inadvertently omitted the Reporting Person's indirect holdings of common stock held by The C. Schor IRRV Trust and The I. Schor IRRV Trust (the "Trusts"), both of which are irrevocable family trusts having independent trustees. There have been no changes to the holdings of the Trusts since the Form 4 filed by the Reporting Person on June 21, 2021, other than as reported on this Form 4. /s/ Nick Harvey, Attorney-in-Fact 2022-08-08