X0609 4 2026-08-10 0 0001377121 Protagonist Therapeutics, Inc PTGX 0001120477 PATEL DINESH V PH D false C/O PROTAGONIST THERAPEUTICS, INC. 7707 GATEWAY BLVD., SUITE 140 NEWARK CA 94560-1160 1 1 0 0 President and CEO 1 Common Stock 2026-08-10 4 M 0 65761 21.58 A 589239 D Common Stock 2026-08-10 4 S 0 65761 149.11 D 523478 D Common Stock 2026-08-11 4 M 0 34239 21.58 A 557717 D Common Stock 2026-08-11 4 S 0 34239 148.52 D 523478 D Stock Option (right to buy) 21.58 2026-08-10 4 M 0 65761 0.00 D 2026-10-11 Common Stock 65761 159239 D Stock Option (right to buy) 21.58 2026-08-11 4 M 0 34239 0.00 D 2026-10-11 Common Stock 34239 125000 D The transactions set forth on this Form 4 were effected pursuant to a 10b5-1 plan adopted by the reporting person on January 30, 2026. The 10b5-1 plan provides for the exercise of fully vested stock options that expire on October 11, 2026, and the sale of shares of common stock acquired upon exercise of the stock options. The price reported represents the weighted average sale price per share. The shares were sold in multiple transactions at prices ranging from $147.41 to $151.29. 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 $147.64 to $151.30. Upon request by the staff of 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. /s/ Matthew Gosling, Attorney-in-Fact for Dinesh V. Patel, Ph.D. 2026-08-12