X0306 4 2020-03-31 0 0001674365 Aptinyx Inc. APTX 0001341382 Topper James N C/O APTINYX INC. 909 DAVIS STREET, SUITE 600 EVANSTON IL 60201 1 0 0 0 Common Stock 2020-03-31 4 A 0 4976 2.16 A 3195055 I See Footnote The shares were issued to the Reporting Person, who elected to take unrestricted shares in lieu of cash compensation for services as a director, pursuant to the Issuer's nonemployee director compensation plan. The number of shares issued was determined by dividing the cash compensation otherwise payable with respect to the quarter by the price of a share on the date of the grant. The shares are held directly by Frazier Life Sciences VIII, L.P. ("FLS-VIII"). FHM Life Sciences VIII, L.P. ("FHM-VIII L.P.") serves as the sole general partner of FLS-VIII and owns no shares directly. FHM Life Sciences VIII, LLC ("FHM-VIII LLC") serves as the sole general partner of FHM-VIII L.P. and owns no shares directly. James N. Topper and Patrick Heron are members of FHM-VIII LLC and share voting and dispositive power over the shares held by FLS-VIII; however, they disclaim beneficial ownership of the shares held by FLS-VIII except to the extent of their pecuniary interests therein. /s/ Ashish Khanna, Attorney-In-Fact 2020-04-02