X0306 4 2018-12-03 0 0001463361 Unity Biotechnology, Inc. UBX 0001609643 Roberts Margo R C/O UNITY BIOTECHNOLOGY, INC. 3280 BAYSHORE BOULEVARD BRISBANE CA 94005 1 0 0 0 Stock Option (right to buy) 13.67 2018-12-03 4 A 0 50661 0.00 A 2028-12-02 Common Stock 50661 50661 D The number of shares underlying the option grant is based on a grant date value of $450,000, which is calculated using the Black-Scholes pricing model with the volume weighted average trading price of a share of Common Stock on the stock exchange on which the Common Stock is then listed or traded for the thirty (30) consecutive trading days ending on the trading day prior to the date of grant and the volatility, risk-free rate and life expectancy assumptions in the Company's most recent public filings disclosing those assumptions. The shares subject to the option will vest and become exercisable with respect to 1/36th of the total number of shares subject to the option in successive, equal monthly installments measured from December 3, 2018, subject to the Reporting Person's continued service relationship with the Issuer on each such vesting date. /s/ Tamara L. Tompkins, as Attorney-in-Fact for Margo R. Roberts 2018-12-04