X0306 4 2019-09-19 0 0001463361 Unity Biotechnology, Inc. UBX 0001416180 Leonard Keith R C/O UNITY BIOTECHNOLOGY, INC. 3280 BAYSHORE BOULEVARD BRISBANE CA 94005 0 1 0 0 Chief Executive Officer Common Stock, $0.0001 par value 210782 D Common Stock, $0.0001 par value 383475 I See Footnote Common Stock, $0.0001 par value 148448 I See Footnote Common Stock, $0.0001 par value 152542 I See Footnote Stock Option (Right to Buy) 3.43 2019-09-19 4 A 0 35525 0.00 A 2019-09-19 2028-01-28 Common Stock 35525 35525 D Includes Restricted Stock Units which vest over time measured from the grant date. The shares are directly held by Andalucia Ventures LLC, a limited liability company in which the Reporting Person holds a controlling interest. The shares are directly held by Pathfinder Investment Fund, LLC, a limited liability company in which the Reporting Person holds a controlling interest. The shares are directly held by Keith Richard Leonard, Jr. 2017 Retained Annuity Trust. On January 29, 2018, Reporting Person was granted an option exercisable for 142,102 shares. Twenty-five percent (25%) of the shares was subject to vesting pursuant to the achievement of a clinical development milestone; in this case proof of concept that treatment with a senolytic drug meaningfully ameliorates a human disease. On September 19, 2019, Issuer's Board of Directors determined that such milestone was achieved. /s/ Tamara L. Tompkins, Attorney-in-Fact for Keith R. Leonard 2019-09-23