November 8, 2018

Sheila Gujrathi, M.D.
President and Chief Executive Officer
Gossamer Bio, Inc.
3013 Science Park Road, Suite 200
San Diego, California 92121

       Re: Gossamer Bio, Inc.
           Draft Registration Statement on Form S-1
           Submitted October 11, 2018
           CIK No. 0001728117

Dear Dr. Gujrathi:

       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
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

Draft Registration Statement on Form S-1

Prospectus Summary
Our Development Programs, page 1

1.     We note that your pipeline table includes the three preclinical programs
that you are
       exploring and that you expect to file an IND application for at least
one of these programs
       in the next twelve months. As your narrative disclosure only briefly
discusses these
       programs, and they are not otherwise discussed in the Summary section,
please explain to
       us why you believe these programs are sufficiently material to your
business to be
       included in your pipeline table.
 Sheila Gujrathi, M.D.
FirstNameBio, Inc.
Gossamer LastNameSheila Gujrathi, M.D.
Comapany 8, 2018
November NameGossamer Bio, Inc.
November 8, 2018 Page 2
Page 2
FirstName LastName
2.       You state here and elsewhere in your prospectus that GB001 is
"potent." Please remove
         all statements that present your conclusions regarding the efficacy of
your product
         candidate as this is a determination within the authority of the U.S.
Food and Drug
         Administration and comparable regulatory bodies.
3.       We note your statement in the first paragraph on page 2 that GB001
showed a statistically
         significant improvement in a Phase 2 trial as compared to placebo.
Balance your
         disclosure by disclosing that GB001 did not meet its primary efficacy
endpoint of forced
         expiratory volume in another Phase 2 trial of 248 patients. Also
disclose the serious
         adverse event that occurred in a Phase 1 trial, and in the Business
section, explain how
         statistical significance relates to the FDA's evidentiary standards of
Our Strategy, page 3

4.       We refer to your statement here that critical components of your
strategy include "rapidly"
         advancing your product candidates through the development process, and
         statements on page 91 that you have received FDA feedback to
"expedite" your
         development programs for GB001 and GB002, and that you plan to seek
         pathways" for GB004. Please tell us why you believe this time frame is
realistic given
         the lengthy and uncertain process of seeking regulatory approval. To
this end, we note
         your statement in the second full paragraph on page 104 that you plan
to discuss the
         possibility of accelerated FDA pathways if you meet the primary
endpoint of your planned
         Phase 2/3 PAH trial and you observe a favorable trend in key secondary
endpoints with a
         tolerable safety profile.
Risks Related to Our Business, page 4

5.       Please expand the last bullet to disclose that your intellectual
property rights for GB002
         and GB004 are in-licensed, and include sublicenses from other third
6.       Please expand your discussion to disclose that your assumptions about
the potential
         approval of your products are based on trial data primarily collected
by other companies,
         as you explain in your risk factor on page 13. In addition, in your
Business discussion of
         the GB001 trials, please clarify whether you have rights to all the
data for the trial
         conducted by Pulmagen and Teijin.
7.       Add a bullet to discuss the concentration of ownership by your
officers, directors and
         principal stockholders, that many of your current directors are
appointed by such
         stockholders, and that HH Goss has the right to designate a board
member and have such
         member appointed to any board committee effective as of the closing of
this offering.
Implications of Being an Emerging Growth Company, page 5

8.       Please supplementally 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,
 Sheila Gujrathi, M.D.
FirstNameBio, Inc.
Gossamer LastNameSheila Gujrathi, M.D.
Comapany 8, 2018
November NameGossamer Bio, Inc.
November 8, 2018 Page 3
Page 3
FirstName LastName
         present to potential investors in reliance on Section 5(d) of the
Securities Act, whether or
         not they retain copies of the communications.
Use of Proceeds, page 67

9.       To the extent known, please revise to separately disclose the
estimated amounts you
         intend to use to continue development of GB001 for its various
indications, and your other
         programs. Please also indicate how far you expect the proceeds of the
offering will allow
         you to proceed with the development of each of your programs. Refer to
Instruction 3 to
         Item 504 of Regulation S-K.
Management's Discussion and Analysis of Financial Condition and Results of
Results of Operations for the Six Months Ended June 30, 2017 and 2018
Research and development, page 79

10.      Please disaggregate research and development expense between
preclinical and clinical. In
         addition, please disaggregate direct research and development expenses
for GB001 and
         GB002 separately. If you cannot disaggregate these amounts please
disclose why.
Critical Accounting Policies and Significant Judgments and Estimates
Stock-based compensation, page 85

11.      Once you have an estimated offering price or range, please explain to
us the reasons
         for any differences between the recent valuations of your common stock
leading up to the
         IPO and the estimated offering price. This information will help
facilitate our review of
         your accounting for equity issuances including stock compensation and
         conversion features.
Clinical Development History of GB001, page 95

12.      We note your statement that you acquired GB001 through your
acquisition of Pulmagen,
         and your disclosure elsewhere in your prospectus that you acquired
rights to GB001
         through your acquisition of AA Biopharma Inc. Please explain to us the
         between Pulmagen and AA Biopharma.
Summary of Completed Japanese Phase 2 Clinical Trial, page 95

13.      Please revise your narrative disclosure regarding Figures 3 and 4 to
explain how the
         measurements reflected in the axes relate to the secondary endpoint of
 Sheila Gujrathi, M.D.
FirstNameBio, Inc.
Gossamer LastNameSheila Gujrathi, M.D.
Comapany 8, 2018
November NameGossamer Bio, Inc.
November 8, 2018 Page 4
Page 4
FirstName LastName
GB004 (HIF-1a Stabilizer), page 104

14.      Please expand your discussion on page 107 to disclose the number of
patients involved in
         the SAD and MAD trials, as well as the dosages used in those trials
and the planned Phase
         1b trial.
License Agreements, page 110

15.      Please revise your discussion of the Pulmokine agreement to disclose
that the licensed
         intellectual property includes rights licensed by Pulmokine from third
parties, including
         any material terms of those agreements that affect your agreement with
Pulmokine, as
         well as the effects of any termination of the third-party licenses.
Also disclose the royalty
         term. Please make corresponding revisions to your discussion on the
Aerpio license
Intellectual Property, page 111

16.      Please revise to disclose the foreign jurisdictions in which you have
issued or pending
         patent applications, the type of patent protection to which they
relate, and expected
         expiration dates.
Principal Stockholders, page 159

17.      Please revise your disclosure to identify the natural person or
persons who have voting
         and investment control of the shares held by HH Goss Holdings LLC.
Financial Statements
Note 9 - Stock-Based Compensation, page F-19

18.      You state "The weighted-average grant date fair value per share for
the stock option grants
         during the six months ended June 30, 2018 was $0.58." In addition the
         fair value of your common stock was $0.58 (exercise price). Please
confirm that the fair
         value of your common stock and the fair value of the options granted
were both $0.58 or
         revise the disclosure as necessary. Refer to ASC 718-10-50-2d1.

19.      Please provide us proofs of all graphics, visual, or photographic
information you will
         provide in the printed prospectus prior to its use, for example in a
preliminary prospectus.
         Please note that we may have comments regarding this material.
 Sheila Gujrathi, M.D.
Gossamer Bio, Inc.
November 8, 2018
Page 5

        You may contact Vanessa Robertson at 202-551-3649 or Lisa Vanjoske at
if you have questions regarding comments on the financial statements and
matters. Please contact Dorrie Yale at 202-551-8776 or Mary Beth Breslin at
202-551-3625 with
any other questions.

FirstName LastNameSheila Gujrathi, M.D.
                                                         Division of
Corporation Finance
Comapany NameGossamer Bio, Inc.
                                                         Office of Healthcare &
November 8, 2018 Page 5
cc:       Matthew Bush
FirstName LastName