X0306 4 2020-02-10 0 0001510487 Principia Biopharma Inc. PRNB 0001751719 Goldstein David C/O PRINCIPIA BIOPHARMA INC. 220 E. GRAND AVENUE SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Scientific Officer Common Stock 2020-02-10 4 M 0 6000 2.9977 A 36968 D Common Stock 2020-02-10 4 S 0 800 69.5269 D 36168 D Common Stock 2020-02-10 4 S 0 5200 71.1113 D 30968 D Employee Stock Option (right to buy) 2.9977 2020-02-10 4 M 0 6000 0.00 D 2023-10-23 Common Stock 6000 8447 D Includes 1,149 shares acquired under the Employment Stock Purchase Plan on November 15, 2019. The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. Represents the weighted average sales price per share. The shares sold at prices ranging from $69.09 to $70.025 per share. Upon request by the Commission staff, 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 within the range set forth in this Form 4. Represents the weighted average sales price per share. The shares sold at prices ranging from $70.77 to $71.28 per share. Upon request by the Commission staff, 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 within the range set forth in this Form 4. The stock option is fully vested and immediately exercisable. /s/ Christopher Y. Chai, Attorney-in-Fact for David Goldstein 2020-02-12