X0609 4 2026-05-19 0001783183 Phathom Pharmaceuticals, Inc. PHAT 0001341382 Topper James N false C/O PHATHOM PHARMACEUTICALS, INC. 100 CAMPUS DRIVE, SUITE 102 FLORHAM PARK, NJ 07932 true false true false false Common Stock 2026-05-19 4 A false 24122 0 A 66718 D Common Stock 59403 I By Frazier Life Sciences X, L.P. Common Stock 5827415 I By Frazier Life Sciences IX, L.P. Common Stock 1 I By FHMLS IX, L.L.C. Common Stock 3912 I By Topper Group III LLC The Restricted Stock Units ("RSUs") were granted on May 19, 2026, pursuant to the Issuer's Non-Employee Director Compensation Program. 100% of the total number of RSUs granted shall vest on the first to occur of (A) the first anniversary of the date of grant or (B) the next occurring annual meeting of the Issuer's stockholders, subject to the Reporting Person's continuing service on the Board through such vesting date. Each RSU represents a contingent right to receive one share of common stock of the Issuer. The shares reported herein are held of record by Frazier Life Sciences X, L.P. FHMLS X, L.P. is the general partner of Frazier Life Sciences X, L.P. and FHMLS X, L.L.C. is the general partner of FHMLS X, L.P. The Reporting Person is one of two managing members of FHMLS X, L.L.C. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. The shares reported herein are held of record by Frazier Life Sciences IX, L.P. FHMLS IX, L.P. is the general partner of Frazier Life Sciences IX, L.P. and FHMLS IX, L.L.C. is the general partner of FHMLS IX, L.P. The Reporting Person is one of two managing members of FHMLS IX, L.L.C. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. The shares reported herein are held of record by FHMLS IX, L.L.C. The Reporting Person is one of two managing members of FHMLS IX, L.L.C. The Reporting Person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. The Reporting Person is a manager of Topper Group III LLC and has voting and investment power of the securities held by Topper Group III LLC. /s/ Anne Marie Cook, Attorney-in-Fact for James Topper 2026-05-21