X0508 4 2023-08-14 0 0001720580 Adicet Bio, Inc. ACET 0001643067 Healey Don C/O ADICET BIO, INC. 200 BERKELEY STREET, 19TH FLOOR BOSTON MA 02116 0 1 0 0 Chief Technology Officer 0 Stock Option (Right to Buy) 13.27 2023-08-14 4 D 0 70000 0.00 D 2031-01-12 Common Stock 70000 0 D Stock Option (Right to Buy) 2.14 2023-08-14 4 A 0 70000 0.00 A 2031-01-12 Common Stock 70000 70000 D Stock Option (Right to Buy) 16.82 2023-08-14 4 D 0 30400 0.00 D 2031-02-11 Common Stock 30400 0 D Stock Option (Right to Buy) 2.14 2023-08-14 4 A 0 30400 0.00 A 2031-02-11 Common Stock 30400 30400 D Stock Option (Right to Buy) 15.52 2023-08-14 4 D 0 125000 0.00 D 2032-01-06 Common Stock 125000 0 D Stock Option (Right to Buy) 2.14 2023-08-14 4 A 0 125000 0.00 A 2032-01-06 Common Stock 125000 125000 D Stock Option (Right to Buy) 9.05 2023-08-14 4 D 0 117200 0.00 D 2033-01-23 Common Stock 117200 0 D Stock Option (Right to Buy) 2.14 2023-08-14 4 A 0 117200 0.00 A 2033-01-23 Common Stock 117200 117200 D Stock Option (Right to Buy) 2.14 2023-08-14 4 A 0 149944 0.00 A 2033-08-13 Common Stock 149944 149944 D On August 8, 2023, the Issuer's Board of Directors approved an option repricing (the "Repricing"), effective as of August 14, 2023 (the "Effective Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable. 25% of the shares subject to this option vested and became exercisable on January 13, 2022, with the remaining 75% vesting in thirty-six (36) equal monthly installments thereafter, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date. The exercise price of the option is $2.14 per share, representing the fair market value per share of the Issuer's Common Stock on the Effective Date; provided that the repriced option will revert to its original exercise price if, prior to the first anniversary of the Effective Date, (a) the Reporting Person's employment is terminated by the Issuer with cause or by the Reporting Person or (b) the option is exercised. 25% of the shares subject to this option vested and became exercisable on February 12, 2022, with the remaining 75% vesting in thirty-six (36) equal monthly installments thereafter, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date. The shares subject to this option shall vest in forty-eight (48) equal installments on each monthly anniversary following January 7, 2022, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date. The shares subject to this option shall vest in forty-eight (48) equal installments on each monthly anniversary following January 24, 2023, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date. Prior to August 14, 2024, no shares shall be vested or exercisable under this option. Effective as of August 14, 2024, the following vesting schedule shall apply: 25% of the shares shall have vested and become exercisable on October 27, 2021, with the remaining 75% vesting in thirty-six (36) equal installments on each monthly anniversary following October 27, 2021, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date. This option was issued to the Reporting Person because his previously awarded option granted under Nasdaq Listing Rule 5635(c)(4) is not eligible for repricing. /s/ Nick Harvey, Attorney-in-Fact 2023-08-16