SecProbe.io

November 14, 2012

Via E -mail
Jay R. Luly, Ph.D.
President and Chief Executive Officer
Enanta Pharmaceuticals, Inc.
500 Arsenal Street
Watertown, Massachusetts 02472

Re: Enanta  Pharmaceuticals, Inc.
Registration Statement on Form S -1
Filed November 6, 2012
  File No. 333 -184779

Dear Dr. Luly:

We have reviewed your registration statement and have the following comment.  Please
respond to this letter by amending your registration statement and providing the requested
information.   If you do not believe this comment applies to your facts and circu mstances or do
not believe an amendment is appropriate, please tell us why in a response.

After reviewing any amendment to your registration statement and the information you
provide in response to this comment, we may have additional comments.

Finan cial Statements, pages F -3 through F -7

1. Please consider the need to update your financial statements and related information for
the year ended September 30, 2012 pursuant to Rule 3 -12 of Regulation S -X.

We urge all persons who are responsible for the acc uracy and adequacy of the disclosure
in the filing to be certain that the filing includes the information the Securities Act of 1933 and
all applicable Securities Act rules require.   Since the company and its management are in
possession of all facts relat ing to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

Notwithstanding our comment, in the event you request acceleration of the effective date
of the pending registration statement please pr ovide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commission from taking any action with respect
to the filing ;

Jay R. Luly, Ph.D.
Enanta Pharmaceuticals, Inc.
November 14, 2012
Page 2

  the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclosure in the filing; and

 the com pany may not assert staff comments and the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Please refer to Rules 460 and 461 regarding requests for acceleration.  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of thei r respective responsibilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed
public offering of the securities specified in the above registration statement.  Please allow
adequate time for us to rev iew any amendment prior to the requested effective date of the
registration statement.

You may contact Christine Allen at (202) 551 -3652 or Mary Mast at (202) 551 -3613 if you
have questions regarding comments on the financial statements and related matters. Please contact
Scot Foley at (202) 551 -3383, John Krug at (202) 551 -3862 or me at (20 2) 551 -3715 with any other
questions.

Sincerely,

 /s/ Daniel  Greenspan for

Jeffrey P. Riedler
Assistant Director

cc: Nathaniel S. Gardiner, Esq.
 Stacie S. Aarestad, Esq.
Edwards Wildman Palmer LLP
111 Huntington Avenue
Boston, Massachusetts 02199