X0609 4 2026-09-30 0 0001377121 Protagonist Therapeutics, Inc PTGX 0001921163 Ali Asif false C/O PROTAGONIST THERAPEUTICS, INC. 7707 GATEWAY BLVD., SUITE 140 NEWARK CA 94560-1160 0 1 0 0 Chief Financial Officer 1 Common Stock 2026-09-30 4 M 0 9229 38.98 A 68232 D Common Stock 2026-09-30 4 M 0 28438 23.42 A 96670 D Common Stock 2026-09-30 4 M 0 15650 19.19 A 112320 D Common Stock 2026-09-30 4 M 0 5312 12.17 A 117632 D Common Stock 2026-09-30 4 S 0 12595 141.77 D 105037 D Common Stock 2026-09-30 4 S 0 46034 141.78 D 59003 D Stock Option (right to buy) 38.98 2026-09-30 4 M 0 9229 0 D 2035-01-01 Common Stock 9229 29291 D Stock Option (right to buy) 23.42 2026-09-30 4 M 0 28438 0 D 2034-01-01 Common Stock 28438 49562 D Stock Option (right to buy) 19.19 2026-09-30 4 M 0 15650 0 D 2032-04-17 Common Stock 15650 51150 D Stock Option (right to buy) 12.17 2026-09-30 4 M 0 5312 0 D 2033-01-15 Common Stock 5312 25235 D The transactions set forth on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on June 30, 2026. The price reported represents the weighted average sale price per share. The shares were sold in multiple transactions at prices ranging from $140.21 to $143.31. Upon request by the staff of the U.S. Securities and Exchange Commission (the "SEC"), the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price. The price reported represents the weighted average sale price per share. The shares were sold in multiple transactions at prices ranging from $140.16 to $143.45. Upon request by the SEC, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price. The stock option vests in 48 equal monthly installments following January 2, 2025, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. The stock option vests in 48 equal monthly installments following January 2, 2024, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. The stock option is fully vested. The stock option vests in 48 equal monthly installments following January 16, 2023, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. /s/ Matthew Gosling, Attorney-in-Fact for Asif Ali 2026-10-02