X0306 4 2017-12-01 0 0001435049 ADURO BIOTECH, INC. ADRO 0001193201 ISAACS STEPHEN T C/O ADURO BIOTECH, INC. 740 HEINZ AVENUE BERKELEY CA 94710 1 1 0 0 President and CEO Common Stock 2017-12-01 4 M 0 40000 0.45 A 213921 D Common Stock 2017-12-01 4 S 0 40000 9.3757 D 173921 D Common Stock 70657 I By Family Trust Stock Option (right to buy) 0.45 2017-12-01 4 M 0 40000 0.00 D 2020-03-18 Common Stock 40000 49259 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 16, 2017. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $9.125 to $9.575, 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 sold at each separate price within the range. The shares are owned directly by the Isaacs-MacBride Family Trust UAD 03/09/01, for which the Reporting Person is a trustee. The shares subject to the Option are fully vested and immediately exercisable. /s/ Jennifer Lew, Attorney-in-Fact 2017-12-04