X0306 4 2022-11-23 0001177648 ENANTA PHARMACEUTICALS INC ENTA 0001185034 MELLETT PAUL J C/O ENANTA PHARMACEUTICALS, INC. 500 ARSENAL STREET WATERTOWN MA 02472 0 1 0 0 Treasurer and CFO Common Stock 2022-11-23 4 A 0 21000 0.00 A 82558 D Stock Option (right to buy) 45.00 2022-11-23 4 A 0 45000 0.00 A 2032-11-23 Common Stock 45000 45000 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 will vest and settle with respect to 25% of the award on December 4, 2023 and in substantially equal annual installments over the next three anniversaries thereafter. 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 23, 2022). /s/ Nathaniel S. Gardiner as attorney-in-fact 2022-11-28