X0306 4 2020-11-20 0001177648 ENANTA PHARMACEUTICALS INC ENTA 0001607643 Gardiner Nathaniel S. C/O ENANTA PHARMACEUTICALS, INC. 500 ARSENAL STREET WATERTOWN MA 02472 0 1 0 0 Sr. VP & General Counsel Common Stock 2020-11-20 4 A 0 7600 0 A 36871 D Common Stock 16645 I By grantor retained annuity trusts Stock Option (right to buy) 43.57 2020-11-20 4 A 0 30800 0 A 2030-11-20 Common Stock 30800 30800 D Represents a grant of restricted stock units ("RSUs") under the Enanta Pharmaceuticals, Inc. ("Enanta") 2019 Equity Incentive Plan. Each RSU represents the contingent right to receive, upon vesting of the unit, one share of Enanta common stock. The RSUs vest in equal annual installments over four years from the date of grant (November 20, 2020). The restricted stock unit shares that vest will be issued on the first December 1 after the applicable vesting date, subject to withholding of a portion of the vested shares to satisfy tax withholding requirements. These shares are held by grantor retained annuity trusts created by the reporting person for the benefit of himself and his two adult children. Such option will become exercisable (subject to the optionholder's continued employment) quarterly in substantially equal installments (any fractional shares to be cumulated and to become exercisable at the end of the earliest succeeding quarterly period in which a whole share equivalent is accumulated) over four years from the date of grant (November 20, 2020). /s/ Nathaniel S. Gardiner 2020-11-20