SecProbe.io

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 CORRESP

 VIA EDGAR
 March 24, 2025 United States Securities and Exchange
Commission Office of Life Sciences Division of Corporation
Finance 100 F Street, N.E. Washington, D.C. 20549

 Re:
 Amylyx Pharmaceuticals, Inc.
 Acceleration Request for Registration Statement on Form S-3
 File No. 333-285525
 Ladies and Gentlemen: Pursuant to Rule 461
under the Securities Act of 1933, as amended (the “ Act ”), Amylyx Pharmaceuticals, Inc. (the “ Company ”) hereby requests that the effective date of the above-referenced registration statement (the
“ Registration Statement ”) be accelerated to March 26, 2025, at 5:00 p.m., Eastern Time, or as soon thereafter as practicable, unless we or our outside counsel, Goodwin Procter LLP, request by telephone that such
Registration Statement be declared effective at some other time. In making this acceleration request, the Company acknowledges that it is aware of its responsibilities under the Act.
 Once the Registration Statement is effective, please orally confirm the event with our counsel, Goodwin Procter LLP by calling Marishka DeToy
at (617) 570-1926. If you have any questions regarding this request, please contact Marishka DeToy of Goodwin Procter LLP at (617) 570-1926.

 Sincerely,

 AMYLYX PHARMACEUTICALS, INC.

 /s/ Joshua B. Cohen

 Joshua B. Cohen

 Co-Chief Executive Officer

 /s/ Justin B. Klee

 Justin B. Klee

 Co-Chief Executive Officer

 cc:
 James M. Frates, Amylyx Pharmaceuticals, Inc.
 Benjamin K. Marsh, Goodwin Procter LLP
 Marishka DeToy, Goodwin Procter LLP

March 5, 2025
Joshua B. Cohen
Co-Chief Executive Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, Massachusetts 02141
Justin B. Klee
Co-Chief Executive Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, Massachusetts 02141
Re:Amylyx Pharmaceuticals, Inc.
Registration Statement on Form S-3
Filed March 4, 2025
File No. 333-285525
Dear Joshua B. Cohen and Justin B. Klee:
            This is to advise you that we have not reviewed and will not review your registration
statement.
            Please refer to Rules 460 and 461 regarding requests for acceleration. 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.
            Please contact Chris Edwards at 202-551-6761 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:Marishka DeToy, Esq.

United States securities and exchange commission logo
December 20, 2023
James Frates
Chief Financial Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, MA 02141
Re:Amylyx Pharmaceuticals, Inc.
Form 10-K for the Fiscal Year Ended December 31, 2022
Filed March 13, 2023
File Number 001-41199
Dear James Frates:
            We have completed our review of your filing. 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.
Sincerely,
Division of Corporation Finance
Office of Life Sciences

CORRESP
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CORRESP

 December 19, 2023

 Securities
and Exchange Commission

 Division of Corporation Finance

Office of Life Sciences

 100 F Street, NE

Washington, DC 20549

 Attn: Ms. Mary Mast and Ms. Angela Connell

 Re: Amylyx Pharmaceuticals, Inc.

 Form 10-K for the Fiscal Year Ended December 31, 2022 Filed March 13, 2023

 Form 10-Q
for the Quarterly Period Ended September 30, 2023 Filed November 9, 2023

 File Number 001-41199

Dear Ms. Mast and Ms. Connell:

 Please find below the response
of Amylyx Pharmaceuticals, Inc. (the “Company”, “we” or “our”), to the comments raised by the staff of the Securities and Exchange Commission (the “Staff”) in its letter dated December 5, 2023 relating to the
Company’s Form 10-K for the Fiscal Year Ended December 31, 2022 filed on March 13, 2023 and the Company’s Form 10-Q for the Quarterly Period Ended September
30, 2023 filed on November 9, 2023, as set forth in your letter dated December 5, 2023 addressed to Mr. James Frates, Chief Financial Officer of the Company.

For your convenience, the Staff’s comments have been restated and are followed by the Company’s response.

Form 10-Q for the Nine Months Ended September 30, 2023

Notes to Condensed Consolidated Financial Statements

3. Product Revenue, Net, page 10

1.
 Please tell us your consideration of providing disaggregated revenue disclosure such as product sales for the
U.S. and Canada. Refer to ASC 606-10-55-89 through 606-10-55-91 and ASC 280-10-50-41.

Company’s Response:

 The Company acknowledges the
Staff’s comment and respectfully advises the Staff that ASC 606-10-55-89 through 91 requires entities to disaggregate
revenue from contracts with customers into categories that depict how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors. The Company respectfully advises the Staff that ASC 280-10-50-41 requires a public entity to report revenues from external customers attributed to the public entity’s country of
domicile and attributed to all foreign countries in total from which the public entity derives

 revenues, unless it is impracticable to do so. If revenues from external customers attributed to an individual foreign
country are material, those revenues shall be disclosed separately. A public entity shall disclose the basis for attributing revenues from external customers to individual countries. In line with these requirements, we respectfully advise the Staff
that product sales from Canada represent less than 4.5% of our total revenues for the nine months ended September 30, 2023. We believe that providing additional disaggregation by additional categories stated in 606-10-55-91, for example, by geographical region, country, market or type of customer, in this case would not significantly enhance investors’ understanding of
our financial performance, given the relative immateriality of Canadian revenue to our overall financial context, and the fact that we have only one approved product for one indication. We do not believe there are material differences in the nature,
timing and risk of cash flows between the U.S. and Canada. As such, we believe our current disclosures meet the objectives of the disclosure requirements of 606-10-55-89 through 606-10-55-91 and ASC 280-10-50-41. At each reporting period, we perform an analysis and update our conclusions on the disaggregated revenue disclosure based on materiality of such
disclosures and the relevant facts and circumstances to comply with the ASC guidance.

 Notes to the Condensed Consolidated Financial Statements

 5. Inventories, page 12

2.
 Your inventory balance was $56.7 million at September 30, 2023, of which $24.3 million is considered long-term.
You state that finished goods have a shelf life of 12—18 months from the date of manufacture. Tell us how much of the long-term inventory is considered finished goods. In light of the shelf life, the early phase of the company’s product
sale launch, and a significant portion of inventories being recorded as long-term, tell us why you believe no impairment was required to be recorded at September 30, 2023.

The Company acknowledges the Staff’s comment and respectfully advises the Staff that ASC
330-10-35-1B requires that when evidence exists that the net realizable value of inventory is lower than its cost, for example,
if due to damage, physical deterioration, obsolescence, changes in price levels, or other causes, the difference shall be recognized as a loss in earnings in the period in which it occurs. In line with these requirements, we regularly review our
inventory for impairment by comparing the cost of inventory with its net realizable value. As of September 30, 2023, none of our long-term inventory was considered finished goods. Long-term inventory consisted of raw materials, which have a current
usable period of approximately two to three years in its raw material form. Raw material has until its stated expiry date to be manufactured into finished goods, at which point the material would have another
12-18 months of useful life. In accordance with ASC 330-10-35, we performed an analysis considering current market conditions and
future demand forecasts to determine whether an impairment was required to be recorded at September 30, 2023. Based on this analysis, we determined that no impairment was necessary as of September 30, 2023, as we expect that our inventory will be
utilized in production or sold prior to reaching its expiry date. At each reporting period, we perform this analysis and update our conclusions based on relevant facts and circumstances.

 Thank you for your attention to these matters. Please direct any questions or further comments regarding this response
letter to Marishka DeToy of Goodwin Procter LLP by email at MDeToy@goodwinlaw.com or by phone at (617) 570-1926.

Sincerely,

 James Frates

Chief Financial Officer

 Amylyx Pharmaceuticals, Inc.

cc:
 Gina Mazzariello, Chief Legal Officer and General Counsel, Amylyx Pharmaceuticals, Inc.

 Benjamin Marsh, Goodwin Procter LLP

Marishka DeToy, Goodwin Procter LLP

United States securities and exchange commission logo
December 5, 2023
James Frates
Chief Financial Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, MA 02141
Re:Amylyx Pharmaceuticals, Inc.
Form 10-K for the Fiscal Year Ended December 31, 2022
Filed March 13, 2023
Form 10-Q for the Quarterly Period Ended September 30, 2023
Filed November 9, 2023
File Number 001-41199
Dear James Frates:
            We have limited our review of your filing to the financial statements and related
disclosures and have the following comments.
            Please respond to this letter within ten business days by providing the requested
information or advise us as soon as possible when you will respond. If you do not believe a
comment applies to your facts and circumstances, please tell us why in your response.
            After reviewing your response to this letter, we may have additional comments.
Form 10-Q for the Nine Months Ended September 30, 2023
Notes to Condensed Consolidated Financial Statements
3. Product Revenue, Net, page 10
1.Please tell us your consideration of providing disaggregated revenue disclosure such as
product sales for the U.S. and Canada.  Refer to ASC 606-10-55-89 through 606-10-55-91
and ASC 280-10-50-41.
Notes to the Condensed Consolidated Financial Statements
5. Inventories, page 12
2.Your inventory balance was $56.7 million at September 30, 2023, of which $24.3 million
is considered long-term.  You state that finished goods have a shelf life of 12 - 18 months
from the date of manufacture.  Tell us how much of the long-term inventory is

 FirstName LastNameJames Frates
 Comapany NameAmylyx Pharmaceuticals, Inc.
 December 5, 2023 Page 2
 FirstName LastName
James Frates
Amylyx Pharmaceuticals, Inc.
December 5, 2023
Page 2
considered finished goods.  In light of the shelf life, the early phase of the company's
product sale launch, and a significant portion of inventories being recorded as long-term,
tell us why you believe no impairment was required to be recorded at September 30, 2023.
            In closing, 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.
            Please contact Mary Mast at 202-551-3613 or Angela Connell at 202-551-3426 with any
questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences

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Acceleration Request

 VIA EDGAR

October 4, 2022

 Office of Life Sciences

Division of Corporation Finance

 United States Securities and
Exchange Commission

 100 F Street, N.E.

 Washington, D.C.
20549

 Attention: Jordan Nimitz

Re:
 Amylyx Pharmaceuticals, Inc.

Acceleration Request for Registration Statement on Form S-1

File No. 333-267730

 Requested
Date:                October 6, 2022

 Requested
Time:                4:00 p.m. Eastern Standard Time

 Dear Mr.
Nimitz:

 Pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), Amylyx Pharmaceuticals, Inc. (the
“Company”) hereby requests that the effective date of the above-referenced registration statement (the “Registration Statement”) be accelerated to October 6, 2022, at 4:00 p.m., Eastern Time, or as soon
thereafter as practicable, unless we or our outside counsel, Goodwin Procter LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this acceleration request, the Company acknowledges that it
is aware of its responsibilities under the Act.

 Once the Registration Statement is effective, please orally confirm the event with our counsel, Goodwin
Procter LLP, by calling Meg Dennard at (212) 813-8927. We also respectfully request that a copy of the written order from the Securities and Exchange Commission verifying the effective time and date of the
Registration Statement be sent to our counsel, Goodwin Procter LLP, Attention: Meg Dennard, by email to MDennard@goodwinlaw.com or by facsimile to (212) 202-4529.

[Remainder of page left intentionally blank]

 If you have any questions regarding this request, please contact Meg Dennard of Goodwin Procter LLP at (212)
813-8927.

Sincerely,

AMYLYX PHARMACEUTICALS, INC.

/s/ Joshua B. Cohen

Joshua B. Cohen

Co-Chief Executive Officer

cc:
 Joseph McCann, Securities and Exchange Commission

Justin B. Klee, Co-Chief Executive Officer, Amylyx Pharmaceuticals, Inc.

James M. Frates, Chief Financial Officer, Amylyx Pharmaceuticals, Inc.

Benjamin K. Marsh, Esq., Goodwin Procter LLP

[Signature Page to Acceleration Request]

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Underwriter Acceleration Request

 Goldman Sachs & Co. LLC

200 West Street

New York, NY 10282

 BofA Securities, Inc.

One Bryant Park

New York, NY 10036

 SVB Securities LLC

53 State Street, 40th Floor

Boston, MA 02109

 Evercore Group L.L.C.

55 E. 52nd St.

 New York,
NY 10055

 VIA EDGAR

October 4, 2022

 United States Securities and Exchange
Commission

 Division of Corporation Finance

 Office of Life
Sciences

 100 F Street, N.E.

 Washington, D.C. 20549

Attention: Jordan Nimitz

Re:
 Amylyx Pharmaceuticals, Inc.

Acceleration Request for Registration Statement on Form S-1

File No. 333-267730

 Dear
Mr. Nimitz:

 Pursuant to Rule 460 of the General Rules and Regulations under the Securities Act of 1933, as amended (the
“Act”), we, as representatives of the several underwriters, wish to advise you that there will be distribution to underwriters, institutions, dealers and others, who are reasonably anticipated to participate in the distribution of
the securities, of as many copies of the preliminary prospectus included in the above-named Registration Statement on Form S-1 (File No. 333-267730) (the “Registration Statement”) as
appears to be reasonable to secure the adequate distribution of the preliminary prospectus.

 We, the undersigned, as representatives of
the several underwriters, have complied and will comply, and have been informed by the participating underwriters that they have complied and will comply with the requirements of Rule 15c2-8 under the
Securities Exchange Act of 1934, as amended.

 In accordance with Rule 461 of the Act, we hereby join in the request of Amylyx
Pharmaceuticals, Inc. for acceleration of the effective date of the Registration Statement so that it becomes effective at 4:00 p.m. Eastern Time on October 6, 2022, or as soon thereafter as practicable or at such other time as the Company or
its outside counsel, Goodwin Procter LLP, request by telephone that the Registration Statement be declared effective.

 [Remainder of
page intentionally left blank]

Very truly yours,

By:

GOLDMAN SACHS & CO. LLC

By:

/s/ Dan Cocks

Name:  Dan Cocks

Title:    Managing Director

By:

BOFA SECURITIES, INC.

By:

/s/ Greg Butz

Name:  Greg Butz

Title:    Managing Director

By:

SVB SECURITIES LLC

By:

/s/ Jon A Civitarese

Name:  Jon A Civitarese

Title:    Sr. Managing Director

By:

EVERCORE GROUP L.L.C.

By:

/s/ Gloria Tang

Name:  Gloria Tang

Title:    Managing Director

 [Signature Page to Acceleration Request Letter]

United States securities and exchange commission logo
August 31, 2022
Justin B. Cohen
Co-Chief Executive Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, Massachusetts 02141
Justin B. Klee
Co-Chief Executive Officer
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, Massachusetts 02141
Re:Amylyx Pharmaceuticals, Inc.
Draft Registration Statement on Form S-1
Submitted August 24, 2022
CIK No. 0001658551
Dear Mr. Cohen:
            This is to advise you that we do not intend to review your registration statement.
            We request that you publicly file your registration statement no later than 48 hours prior
to the requested effective date and time. Please refer to Rules 460 and 461 regarding requests for
acceleration. 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.
            Please contact Jordan Nimitz at 202-551-5831 with any questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences

CORRESP
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CORRESP

 Goldman Sachs & Co. LLC

 200 West
Street

 New York, NY 10282

 SVB Leerink LLC

 53 State Street, 40th Floor

Boston, MA 02109

 Evercore Group L.L.C.

 55 E. 52nd St.

New York, NY 10055

 VIA EDGAR

January 4, 2022

 United States Securities and Exchange
Commission

 Division of Corporation Finance

 Office of Life
Sciences

 100 F Street, N.E.

 Washington, D.C. 20549

Attention: Daniel Crawford

 Joe McCann

Re:
 Amylyx Pharmaceuticals, Inc.

Acceleration Request for Registration Statement on Form S-1

File No. 333-261703

Dear Messrs. Crawford and McCann:

 Pursuant to
Rule 460 of the General Rules and Regulations under the Securities Act of 1933, as amended (the “Act”), we, as representatives of the several underwriters, wish to advise you that approximately 2,817 copies of the preliminary
prospectus included in the above-named registration statement (the “Registration Statement”) were distributed during the period January 3, 2022 through the date hereof, to prospective underwriters, institutions, dealers and
others.

 We, the undersigned, as representatives of the several underwriters, have complied and will comply, and have been informed by the
participating underwriters that they have complied and will comply with the requirements of Rule 15c2-8 under the Securities Exchange Act of 1934, as amended.

In accordance with Rule 461 of the Act, we hereby join in the request of Amylyx Pharmaceuticals, Inc. for acceleration of the effective
date of the Registration Statement so that it becomes effective at 4:00 p.m. Eastern Time on January 6, 2022, or as soon thereafter as practicable or at such other time as the Company or its outside counsel, Goodwin Procter LLP,
request by telephone that the Registration Statement be declared effective.

 [Remainder of page intentionally left blank]

Very truly yours,

By:

GOLDMAN SACHS & CO. LLC

By:

 /s/ Danielle Freeman

Name: Danielle Freeman

Title: Managing Director

By:

SVB LEERINK LLC

By:

 /s/ Jon Civitarese

Name: Jon Civitarese

Title: Managing Director

By:

EVERCORE GROUP L.L.C.

By:

 /s/ Gloria Tang

Name: Gloria Tang

Title: Managing Director

 [Signature Page to Acceleration Request Letter]

CORRESP
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CORRESP

 VIA EDGAR

January 4, 2022

 Office of Life Sciences

Division of Corporation Finance

 United States Securities and
Exchange Commission

 100 F Street, N.E.

 Washington, D.C.
20549

 Attention: Daniel Crawford

 Joe McCann

Re:
 Amylyx Pharmaceuticals, Inc.

Acceleration Request for Registration Statement on Form S-1

File No. 333-261703

Requested Date:                January 6, 2022

Requested Time:                4:00 p.m. Eastern
Standard Time

 Dear Messrs. Crawford and McCann:

Pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), Amylyx Pharmaceuticals, Inc. (the
“Company”) hereby requests that the effective date of the above-referenced registration statement (the “Registration Statement”) be accelerated to January 6, 2022, at 4:00 p.m., Eastern Time, or as soon
thereafter as practicable, unless we or our outside counsel, Goodwin Procter LLP, request by telephone that such Registration Statement be declared effective at some other time. In making this acceleration request, the Company acknowledges that it
is aware of its responsibilities under the Act.

 Once the Registration Statement is effective, please orally confirm the event with our
counsel, Goodwin Procter LLP, by calling Thomas J. Schaad at (212) 813-8987. We also respectfully request that a copy of the written order from the Securities and Exchange Commission verifying the effective
time and date of the Registration Statement be sent to our counsel, Goodwin Procter LLP, Attention: Thomas J. Schaad, by email to TSchaad@goodwinlaw.com or by facsimile to (212) 954-5309.

[Remainder of page left intentionally blank]

 If you have any questions regarding this request, please contact Thomas J. Schaad of Goodwin
Procter LLP at (212) 813-8987.

Sincerely,

AMYLYX PHARMACEUTICALS, INC.

 /s/ Joshua B. Cohen

Joshua B. Cohen

Co-Chief Executive Officer

cc:
 Justin B. Klee, Co-Chief Executive Officer, Amylyx Pharmaceuticals,
Inc.

 James M. Frates, Chief Financial Officer, Amylyx Pharmaceuticals, Inc.

Benjamin K. Marsh, Esq., Goodwin Procter LLP

 [Signature Page to
Acceleration Request]

CORRESP
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CORRESP

 Goodwin Procter LLP

 100
Northern Avenue

 Boston, MA 02210

goodwinlaw.com

 +1 617 570 1000

 December 16, 2021

VIA EDGAR

 U.S. Securities and Exchange
Commission

 Division of Corporation Finance

 Office of Life
Sciences

 100 F Street NE

 Washington, DC 20549

Attention:
 Christine Torney

 Al Pavot

 Daniel Crawford

 Joe McCann

Re:
 Amylyx Pharmaceuticals, Inc.

 Amendment No. 2 to Draft Registration Statement on Form S-1

 Submitted November 24, 2021

 CIK No. 0001658551

Ladies and Gentlemen:

 This letter is
confidentially submitted on behalf of Amylyx Pharmaceuticals, Inc. (the “Company”) in response to the comments of the staff of the Division of Corporation Finance (the “Staff”) of the U.S. Securities and Exchange
Commission (the “Commission”) with respect to the Company’s Amendment No. 2 to the Draft Registration Statement on Form S-1, confidentially submitted on November 24, 2021
(“Amendment No. 2”), as set forth in the Staff’s letter dated May 27, 2021 (the “May Comment Letter”) and the Staff’s letter dated December 9, 2021 (the “December Comment
Letter” and together with the May Comment Letter, the “Comment Letters”) addressed to Joshua B. Cohen and Justin B. Klee, the Company’s Co-Chief Executive Officers. The
Company is publicly filing the Registration Statement (the “Registration Statement”), which includes changes to reflect responses to the Staff’s comments and other updates.

For reference purposes, the text of the Comment Letters has been reproduced herein with responses below each numbered comment. For your
convenience, we have italicized the reproduced Staff comments from the Comment Letters. Unless otherwise indicated, page references in the descriptions of the Staff’s comments refer to Amendment No. 2, and page references in the responses
refer to the Registration Statement. All capitalized terms used and not otherwise defined herein shall have the meanings set forth in the Registration Statement.

The responses provided herein are based upon information provided to Goodwin Procter LLP by the Company. In addition to submitting this letter
via EDGAR, we are sending via email a copy of each of this letter and the Registration Statement (marked to show changes from Amendment No. 2).

 U.S. Securities and Exchange Commission

December 16, 2021

  Page
 2

 Responses to Comment Letter dated May 27, 2021

Clinical Development of AMX0035 for ALS, page 130 of the Draft Registration Statement confidentially submitted on April 26, 2021

9.
 Please revise to present the full open label extension results or advise.

RESPONSE: In response to the Staff’s comment 9 from the May Comment Letter, the Company respectfully advises the Staff that the
Company is continuing to collect and analyze patient follow-up data on from the open label extension, or OLE, of the CENTAUR trial. As such, the Company is not in a position at this stage to present and disclose the full OLE data. The Company
advises the Staff that the results of its CENTAUR trial were published in September 2020 in the New England Journal of Medicine and in October 2020 in the Journal of Muscle & Nerve. Trial results showed that patients receiving
AMX0035 experienced statistically significant benefit in function, as measured by the Revised ALS Functional Rating Scale, as well as statistically significant improvement in overall survival, when analyzing the randomized population who received at
least one dose of AMX0035 or placebo through the OLE trial up to a July 20, 2020 data cutoff. The Company respectfully submits that the current disclosure provides investors with the necessary material information regarding the CENTAUR trial based
on the above-referenced peer-reviewed publications of the CENTAUR trial data prior to the July 20, 2020 cutoff.

 Principal Stockholders, page 193 of
the Draft Registration Statement confidentially submitted on April 26, 2021

18.
 Please identify the natural person(s) with voting and/or dispositive power over the shares owned by ALS
Invest 1 B.V. and Morningside Venture Investments Limited.

 RESPONSE: In response to the Staff’s comment,
the Company respectfully advises the Staff that it has revised its disclosure on page 203 of Registration Statement.

 Responses to Comment Letter dated
December 9, 2021

 Amendment No. 2 to Draft Registration Statement submitted November 24, 2021

Summary

 Overview, page 2

1.
 With reference to the disclosure on page 144 concerning the PEGASUS trial, please balance the
discussion on page 2 regarding topline results to explain that no differences were seen in the primary or secondary efficacy endpoints.

RESPONSE: In response to the Staff’s comment, the Company respectfully advises the Staff that it has revised its disclosure on
page 2 of Registration Statement to explain that no differences were seen in the secondary efficacy endpoints. The Company further advises the Staff that the PEGASUS trial did not have a primary efficacy endpoint and the Company has revised its
disclosure in the Registration Statement to remove references to a primary efficacy endpoint for the PEGASUS trial.

 Clinical Development of AMX0035
for AD, page 144

2.
 We note your revised disclosures on page 144 presenting the topline results from the PEGASUS trial.
Please revise to identify the primary safety and tolerability endpoints and the trial results. Also revise to present the primary efficacy endpoint as well as the additional cognition, function, and imaging endpoints. Present the efficacy trial
results so they can be compared to the established endpoints. Also, explain the newly developed composite outcome of cognitive, functional, and imaging measures.

RESPONSE: In response to the Staff’s comment, the Company respectfully advises the Staff that it has revised its disclosure on
pages 144, 145, and 146 of Registration Statement to identify the primary safety and tolerability endpoint and secondary efficacy endpoints as well as the biomarkers that were analyzed in the trial. The Company has also added an explanation of
the newly developed composite outcome of cognitive, functional, and imaging measures named the Global Statistical Test, which is a combination of three change-from-baseline to end-of-study endpoints: Cognition (Modified Alzheimer’s Disease
Composite Score, or MADCOMS), Function (Functional Activities Questionnaire, or FAQ) and Total Hippocampal Brain Volume (Magnetic Resonance Imaging, or MRI).

***

 Goodwin Procter LLP

 100
Northern Avenue

 Boston, MA 02210

goodwinlaw.com

 +1 617 570 1000

 If you should have any questions regarding the enclosed matters, please contact me at (212) 813-8816.

Sincerely,

/s/ Benjamin K. Marsh, Esq.

Benjamin K. Marsh, Esq.

 Enclosures

cc:
 Joshua B. Cohen, Co-Chief Executive Officer, Amylyx Pharmaceuticals,
Inc.

 Justin B. Klee, Co-Chief Executive Officer, Amylyx Pharmaceuticals,
Inc.

 James Frates, Chief Financial Officer, Amylyx Pharmaceuticals, Inc.

Mitchell S. Bloom, Esq., Goodwin Procter LLP

United States securities and exchange commission logo
December 9, 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. 2 to Draft Registration Statement on Form S-1
Submitted November 24, 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. 2 to Draft Registration Statement submitted November 24, 2021
Summary
Overview, page 2
1.With reference to the disclosure on page 144 concerning the PEGASUS trial, please
balance the discussion on page 2 regarding topline results to explain that no differences
were seen in the primary or secondary efficacy endpoints.

 FirstName LastNameJoshua B. Cohen, Justin B. Klee
 Comapany NameAmylyx Pharmaceuticals, Inc.
 December 9, 2021 Page 2
 FirstName LastName
Joshua B. Cohen, Justin B. Klee
Amylyx Pharmaceuticals, Inc.
December 9, 2021
Page 2
Clinical Development of AMX0035 for AD, page 144
2.We note your revised disclosures on page 144 presenting the topline results from the
PEGASUS trial.  Please revise to identify the primary safety and tolerability endpoints
and the trial results.  Also revise to present the primary efficacy endpoint as well as the
additional cognition, function, and imaging endpoints.  Present the efficacy trial results so
they can be compared to the established endpoints.  Also, explain the newly developed
composite outcome of cognitive, functional, and imaging measures.
            You may contact Al Pavot at 202-551-3738 or Christine Torney at 202-551-3652 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,
Division of Corporation Finance
Office of Life Sciences
cc:       Benjamin K. Marsh, Esq.

United States securities and exchange commission logo
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

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

United States securities and exchange commission logo
May 27, 2021
Joshua B. Cohen, Justin B. Klee
Co-Chief Executive Officers
Amylyx Pharmaceuticals, Inc.
43 Thorndike St.
Cambridge, Massachusetts 02141
Re:Amylyx Pharmaceuticals, Inc.
Draft Registration Statement on Form S-1
Submitted April 26, 2021
CIK No, 0001658551
Dear Mr. Cohen:
            We have reviewed your 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.
Draft Registration Statement on Form S-1
Summary, page 1
1.Please revise to explain the term “foundational therapy.”
2.Please revise the disclosure on page 1 to explain why FDA has requested that you conduct
an additional trial in support of a New Drug Application. Identify the type(s) of topline
data that you seek from the Phase 3 trial to support the NDA submission.
3.Please address the following with respect to your pipeline table:
•revise to clearly demarcate where each phase or column begins and ends;
•revise the first arrow to clarify that you did not conduct a Phase 3 trial, or advise; and
•include upcoming milestones for the bottom two indications, or advise.

 FirstName LastNameJoshua B. Cohen, Justin B. Klee
 Comapany NameAmylyx Pharmaceuticals, Inc.
 May 27, 2021 Page 2
 FirstName LastNameJoshua B. Cohen, Justin B. Klee
Amylyx Pharmaceuticals, Inc.
May 27, 2021
Page 2
4.Please revise the Pipeline Overview to clarify that the PB and TURSO molecules are not
proprietary and to clarify more specifically what is proprietary.
5.With reference to the risk factor disclosure on page 27, please revise the disclosure on
page 3 to explain that the EU and Canadian authorizations you are seeking may be limited
or subject to restrictions, or advise.
6.Please revise the Summary, where appropriate, to highlight:
•your disclosure on page 33 that you are aware of one ongoing clinical study in
Europe which is evaluating the effects on ALS of TURSO, one of the two
components in AMX0035, and
•your disclosure on page 69 that there is uncertainty as to whether claims in your
pending patent applications, including those claims covering the composition of
matter of AMX0035, will be considered patentable by the USPTO or by patent
offices in foreign countries.
The Offering, page 9
7.Please disclose on page 10 whether the number of shares of your common stock to be
outstanding after this offering includes or excludes shares of your common stock that may
be issuable upon conversion of the $27.3 million of convertible promissory notes you
issued and sold to investors in January 2021.
Clinical Development of AMX0035 for ALS, page 130
8.Please revise here and on page 3 to explain who conducted and funded the survey and its
purpose.  Present in the Business section all material information concerning how the trial
was conducted and its results.
9.Please revise to present the full open label extension results or advise.
Clinical Development Plan of AMX0035 in ALS, page 135
10.We note your disclosure concerning the size and duration of the planned Phase 3 trial.
Please revise to identify the primary endpoint(s) or revise to clarify, if true, that the
endpoint(s) are yet to be determined.
Clinical Development of AMX0035 for Alzheimers Disease, page 136
11.Please revise to qualitatively and/or quantitatively discuss each of the key endpoints.
Commercialization, page 138
12.Please revise the discussion to explain in greater detail your plans for obtaining coverage
and reimbursement for AMX0035 to treat ALS in the U.S., Canada and the EU. For
instance, please discuss, if material, whether your plan is to obtain coverage and
reimbursement that is similar to the two currently approved ALS treatments cited on page
139.  Explain what you would need to demonstrate in order to achieve “orphan drug-like

 FirstName LastNameJoshua B. Cohen, Justin B. Klee
 Comapany NameAmylyx Pharmaceuticals, Inc.
 May 27, 2021 Page 3
 FirstName LastName
Joshua B. Cohen, Justin B. Klee
Amylyx Pharmaceuticals, Inc.
May 27, 2021
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prices in ALS” in specific geographies.  As applicable, discuss reimbursement codes and
the dollar values associated with them.
13.Revise to discuss the duration of patient treatments. For instance, we note that your
CENTAUR trial measured median survival rates.
14.With reference to your disclosure on page 167, please discuss when you would need to
decide whether expensive pharmacoeconomic studies will or will not be necessary to
demonstrate medical necessity and cost-effectiveness of AMX0035.
Intellectual Property, page 142
15.Please expand your disclosure to address the following:
•for each of your patent families, disclose the foreign jurisdictions where you have
been issued or granted patents and where you have patent applications pending;
•for your second and third patent families, disclose any pending patent applications
you have and the jurisdiction(s), thereof.
In this regard, it may be useful to provide tabular disclosure.
16.With reference to the disclosure on page 69, please revise your intellectual property
discussion to address the significance of composition of matter patents to each patent
family.  With reference to your disclosures on pages 128-129, discuss whether these or
other patents cover specific ratios of PB and TURSO.  Also identify your one issued
composition of matter patent and describe your issued European Patent, EP2978419 in
greater detail.
Certain Relationships and Related Party Transactions
2021 Convertible Promissory Note Financing, page 190
17.Please expand your disclosure to describe the material terms of the 2021 Notes, including
the terms of their conversion.
Principal Stockholders, page 193
18.Please identify the natural person(s) with voting and/or dispositive power over the shares
owned by ALS Invest 1 B.V. and Morningside Venture Investments Limited.
General
19.Please provide us with copies of all written communications, as defined in Rule 405 under
the Securities Act, that you, or anyone authorized to do so on your behalf, present to
potential investors in reliance on Section 5(d) of the Securities Act, whether or not they
retain copies of the communications.

 FirstName LastNameJoshua B. Cohen, Justin B. Klee
 Comapany NameAmylyx Pharmaceuticals, Inc.
 May 27, 2021 Page 4
 FirstName LastName
Joshua B. Cohen, Justin B. Klee
Amylyx Pharmaceuticals, Inc.
May 27, 2021
Page 4
            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 David Gessert at (202) 551-2326 or Joe McCann at (202) 551-6262 with any other
questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Benjamin K. Marsh, Esq.