X0306 4 2018-05-15 0 0001377121 Protagonist Therapeutics, Inc PTGX 0001740847 Giraudo Bryan 7707 GATEWAY BLVD., SUITE 140 NEWARK CA 94560-1160 1 0 0 0 Common Stock 2017-05-16 4 P 0 10000 6.4566 A 10000 D Stock Option (right to buy) 6.45 2018-05-15 4 A 0 24000 0.00 A 2028-05-14 Common Stock 24000 24000 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $6.43 to $6.50, inclusive. The Reporting Person undertakes to provide to 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 purchased at each separate price within the range. The shares subject to the option shall vest in 36 equal monthly installments from the vesting commencement date of May 15, 2018. /s/ Thomas P. O'Neil, Attorney-in-Fact 2018-05-17