X0306 4 2021-10-07 0 0001783183 Phathom Pharmaceuticals, Inc. PHAT 0001378847 Socks David A C/O PHATHOM PHARMACEUTICALS, INC. 100 CAMPUS DRIVE, SUITE 102 FLORHAM PAK NJ 07932 1 0 0 0 Common Stock 2021-10-07 4 S 0 15471 32.6639 D 1213875 I David A. Socks 2013 Revocable Trust Common Stock 2021-10-08 4 S 0 2529 32.049 D 1211346 I David A. Socks 2013 Revocable Trust Common Stock 409.73 I By 401(k) All sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.17 to $33.16. The reporting person undertakes to provide Phathom Pharmaceuticals, Inc. (the "Company"), any security holder of the Company, 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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.82 to $32.58. The reporting person undertakes to provide the Company, any security holder of the Company, 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 David A. Socks 2021-10-08