SecProbe.io

Mail Stop 4720
March 29, 2016

David G. Lowe, Ph.D.
Chief Executive Officer
Aeglea BioTherapeutics, Inc.
901 S. MoPac Expressway
Barton Oaks Plaza One
Suite 250
Austin, TX 78746

Re: Aeglea BioTherapeutics, Inc.
Amendment No. 4 to Registration Statement on
Form S -1
Filed March 28, 2016
  File No. 333-205001

Dear Dr. Lowe :

We have reviewed your amended 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 our comment applies to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.

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

Notes to Consolidated Financial Statements
6.  Convertible Preferred Shares/Stock
Conversion, page F -18

1.  Throughout your prospectus, you assume the automatic conversion of all outstanding
 shares of your convertible preferred stock into shares of common stock immediately
 prior to the completion of this offering.  Since your offering does not appear to fulfil l
 the conditions of the automatic conversion herein, please tell us your basis for
 assuming the automatic conversion.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing inc ludes the information the Securities Act of 193 3 and
all applicable Securities  Act rules require.   Since the company and its management are in

David G. Lowe, Ph.D.
Aeglea Bi oTherapeutics, Inc.
March 29, 2016
Page 2

 possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of  the disclosures they have made.

Notwithstanding our comments, in the event you request acceleration of the effective date
of the pending regist ration statement, please provide  a written statement from the company
acknowledging that:

 should the Commiss ion 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;

 the action of the Commission or the staff, acting pursuant to delegated author ity, 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 company 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 reque sts 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 their respective responsibilities under
the Securitie s 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 review any amendment prior to the requested effectiv e date of the
registration statement.

You may contact Keira Nakada at (202) 551 -3659 or Joel Parker at 202 -551-3651  if you
have questions regarding comments on the financial statements and related matters.  Please
contact Christina Thomas at (202) 55 1-3577, Mary Beth Breslin at (202) 551 -3625 or me at
(202) 551 -3675 with any other questions.

Sincerely,

 /s/ Mary Beth Breslin for

 Suzanne Hayes
Assistant Director
Office of Healthcare and Insurance
cc: Robert A. Freedman
 Fenwick & West LLP