X0306 4 2020-02-25 0 0001435049 ADURO BIOTECH, INC. ADRO 0001714425 van Elsas Andrea KLOOSTERSTRAAT 9 OSS P7 5349 AB NETHERLANDS 0 1 0 0 Chief Scientific Officer Common Stock 2020-02-25 4 S 0 6823 3.5107 D 438367 D The shares were sold to cover the tax obligation that occurred upon the vesting of RSUs. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $3.37 to $3.70, 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. /s/ Celeste Ferber, Attorney-in-Fact for Andrea van Elsas 2020-02-26