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                             December 1, 2021

       Chris Schelling
       President and Chief Executive Officer
       Acer Therapeutics Inc.
       One Gateway Center, Suite 351
       300 Washington Street
       Newton, MA 02458

                                                        Re: Acer Therapeutics
Inc.
                                                            Registration
Statement on Form S-3
                                                            Filed November 24,
2021
                                                            File No. 333-261342

       Dear Mr. Schelling:

               We have limited our review of your registration statement to
those issues we have
       addressed in our 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 reviewing any amendment to your registration statement and
the information you
       provide in response to our comment, we may have additional comments.

       Registration Statement on Form S-3

       General

   1.                                                   It appears your public
float is not sufficient to meet the Transaction Requirement in
                                                        Instruction I.B.1 of
Form S-3. To the extent you intend rely on Instruction I.B.6 of Form
                                                        S-3, please file a
pre-effective amendment to provide the information required on the
                                                        cover page. Refer to
Instruction 7 of Form S-3.
               We remind you that the company and its management are
responsible for the accuracy
       and adequacy of their disclosures, notwithstanding any review, comments,
action or absence of
       action by the staff.

              Refer to Rules 460 and 461 regarding requests for acceleration.
Please allow adequate
       time for us to review any amendment prior to the requested effective
date of the registration
       statement.
 Chris Schelling
Acer Therapeutics Inc.
December 1, 2021
Page 2

       Please contact Abby Adams at (202) 551-6902 or Celeste Murphy at (202)
551-3257 with
any questions.



                                                        Sincerely,
FirstName LastNameChris Schelling
                                                        Division of Corporation
Finance
Comapany NameAcer Therapeutics Inc.
                                                        Office of Life Sciences
December 1, 2021 Page 2
cc:       Patty DeGaetano, Esq.
FirstName LastName