X0306 4 2022-05-13 0 0001783183 Phathom Pharmaceuticals, Inc. PHAT 0001363812 Henderson Molly C/O PHATHOM PHARMACEUTICALS, INC. 100 CAMPUS DRIVE, SUITE 102 FLORHAM NJ 07932 0 1 0 0 CFO and CBO Common Stock 2022-05-13 4 P 0 6000 A 26000 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $7.50 to $7.90. The reporting person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Larry Miller, Attorney-in-Fact for Molly Henderson 2022-05-16