Ownership Submission
FORM 4
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 OF SECURITIES

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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
Or Yat Sun
  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)
Sr. VP & CSO
(Last)
(First)
(Middle)
C/O ENANTA PHARMACEUTICALS, INC., 500 ARSENAL STREET
3. Date of Earliest Transaction (Month/Day/Year)
02/12/2018
(Street)

WATERTOWN, MA 02472
4. If Amendment, Date Original Filed(Month/Day/Year)
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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 02/12/2018   A   2,600 (1) A $ 0 306,317 D  
Common Stock 02/12/2018   A   6,269 (2) A $ 0 312,586 D  
Common Stock 02/12/2018   F   2,666 (3) D $ 76.845 309,920 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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
(Month/Day/Year)
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

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Or Yat Sun
C/O ENANTA PHARMACEUTICALS, INC.
500 ARSENAL STREET
WATERTOWN, MA 02472
      Sr. VP & CSO  

Signatures

 /s/ Nathaniel S. Gardiner as attorney-in-fact   02/13/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Represents shares of Enanta common stock issued under a performance share unit ("PSU") award granted on December 21, 2015 that vested as a result of the achievement of a clinical development milestone in calendar 2018 as determined by the Compensation Committee of Enanta's Board of Directors, and then settled with the issuance of the shares of Enanta common stock on February 12, 2018.
(2) Represents shares of Enanta common stock issued under a relative total stockholder return unit ("rTSRU") award granted to the reporting person on December 21, 2015 that was subject to performance-vesting restrictions based on the relative total stockholder return of Enanta's common stock in relation to the total stockholder return of the component companies in the Nasdaq Biotech Index over a two-year period. The performance level was determined by the Compensation Committee of Enanta's Board of Directors and the rTSRU settled with the issuance of the shares of Enanta common stock on February 12, 2018.
(3) Represents the number of shares of common stock automatically forfeited by the reporting person to cover withholding taxes due as a result of settlement of the PSU and rTSRU awards.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.