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                             November 22, 2021

       Joshua B. Cohen, Justin B. Klee
       Co-Chief Executive Officers
       Amylyx Pharmaceuticals, Inc.
       43 Thorndike St.
       Cambridge, Massachusetts 02141

                                                        Re: Amylyx
Pharmaceuticals, Inc.
                                                            Amendment No. 1 to
Draft Registration Statement on Form S-1
                                                            Submitted October
20, 2021
                                                            CIK No, 0001658551

       Dear Mr. Cohen:

             We have reviewed your amended draft registration statement and
have the following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. If you do not believe our comments apply to your facts and
circumstances or do not
       believe an amendment is appropriate, please tell us why in your
response.

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional
       comments.

       Amendment No. 1 to Draft Registration Statement submitted October 20,
2021

       Summary, page 1

   1.                                                   With reference to the
disclosure on page 127, please revise the second paragraph of the
                                                        Overview to describe
briefly the type of    models    that you reference.
   2.                                                   We note your revised
disclosure in response to prior comment 2. Please revise the
                                                        disclosure on pages 1
and 4 to clarify why you plan in Q4 to submit an NDA to FDA
                                                        while also commencing
the Phase 3 PHOENIX trial. To the extent that it is atypical to
                                                        submit an NDA in
advance of, or in connection with, a Phase 3 trial, the circumstances
                                                        and material
discussions with FDA should be highlighted. With reference to disclosures
                                                        on pages 21 and 27,
also revise to explain that FDA may determine, among other things,
                                                        to not approve your NDA
because it disagrees with your data and rationale, or to require
 Joshua B. Cohen, Justin B. Klee
Amylyx Pharmaceuticals, Inc.
November 22, 2021
Page 2
       completion of your planned Phase 3 PHOENIX global clinical trial before
issuing an
       approval decision.
3.     We note your revised disclosure on page 6 in response to prior comment
6. Please revise
       the Summary to highlight your disclosure on page 33 indicating that
there are risks
       that the Humanitas Mirasole SpA Phase 3 trial could result in a
competitive
       commercialized product. Also, revise the disclosure on page 6 to avoid
the implication
       that you are collaborating with Humanitas Mirasole SpA, or advise.
Pipeline Overview, page 2

4.     We note your revised Pipeline Overview disclosure in response to prior
comment 3.
       Please revise the Canadian ALS graphic so that Phase 3 is in grey and
add    N/A    or
       something similar to depict visually that such trial is not required.
5.     Please revise to remove the two unidentified neurodegenerative
indications that you added
       to the table. In this regard, it appears premature to highlight these
unidentified indications
       in the Summary, particularly given that the Business section does not
contain any
       discussion regarding these indications or the development work that has
been conducted
       to date.
Clinical Development of AMX0035 for Wolfram Syndrome, page 136

6.     Please revise to provide support for your statement that AMX0035 has
shown beneficial
       effects in a variety of models of Wolfram syndrome, including cellular
models, patient
       derived cell lines, and a knockout mouse model.
Intellectual Property, page 141

7.     We note your responses to prior comments 6 and 16 and reissue in part.
Please revise
       to identify the issued patent having claims that cover the composition
of matter of
       AMX0035.
       You may contact Christine Torney at (202) 551-3652 and Al Pavot at (202)
551-3738 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Daniel Crawford at (202) 551-7767 or Joe McCann at (202) 551-6262 with
any other
questions.



                                                              Sincerely,
FirstName LastNameJoshua B. Cohen, Justin B. Klee
                                                              Division of
Corporation Finance
Comapany NameAmylyx Pharmaceuticals, Inc.
                                                              Office of Life
Sciences
November 22, 2021 Page 2
cc:       Benjamin K. Marsh, Esq.
FirstName LastName