Sec Form 3 Filing - Trout Harry R. III @ ENANTA PHARMACEUTICALS INC - 2025-08-26

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Trout Harry R. III 2. Issuer Name and Ticker or Trading Symbol ENANTA PHARMACEUTICALS INC [ ENTA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Vice President, Finance (Last) (First) (Middle) C/O ENANTA PHARMACEUTICALS, INC., 4 KINGSBURY AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 08/26/2025 (Street) WATERTOWN, MA02472 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 10,912 ( 1 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (right to buy) $ 81.2 ( 2 ) 11/16/2028 Common Stock 7,110 D Stock Option (right to buy) $ 63.35 ( 2 ) 11/18/2029 Common Stock 10,000 D Stock Option (right to buy) $ 43.57 ( 2 ) 11/20/2030 Common Stock 4,987 D Stock Option (right to buy) $ 75.33 ( 3 ) 11/19/2031 Common Stock 6,048 D Stock Option (right to buy) $ 45 ( 4 ) 11/23/2032 Common Stock 5,571 D Stock Option (right to buy) $ 8.99 ( 5 ) 11/22/2033 Common Stock 9,075 D Stock Option (right to buy) $ 8.83 ( 6 ) 11/27/2034 Common Stock 10,175 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Trout Harry R. III C/O ENANTA PHARMACEUTICALS, INC. 4 KINGSBURY AVENUE WATERTOWN, MA02472 Vice President, Finance Signatures /s/ Matthew Kowalsky as attorney-in-fact 09/08/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Consists of 762 shares of common stock held by the reporting person and 10,150 shares of common stock underlying unvested restricted stock units ("RSUs") granted 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 as follows: (i) 359 RSUs will vest and settle on December 1, 2025, (ii) 1,300 RSUs will vest and settle in two substantially equal annual installments beginning on December 4, 2025, (iii) 3,403 RSUs will vest and settle in three substantially equal annual installments beginning on December 4, 2025, and (iv) 5,088 RSUs will vest and settle in four substantially equal annual installments beginning on December 1, 2025. ( 2 )100% of the shares subject to the option are fully vested and exercisable. ( 3 )Such option has or 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 19, 2021). ( 4 )Such option has or 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). ( 5 )Such option has or 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 22, 2023). ( 6 )Such option has or 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 27, 2024).

Remarks: Exhibit 24 Power of Attorney filed herewith.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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