SecProbe.io

November 7, 2019
Grant E. Pickering
President and Chief Executive Officer
SutroVax, Inc.
353 Hatch Drive
Foster City, California 94404
Re:SutroVax, Inc.
Draft Registration Statement on Form S-1
Submitted October 11, 2019
CIK No. 0001649094
Dear Mr. Pickering:
            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
Prospectus Summary, page 1
1.Please revise your statement here and elsewhere in the prospectus that SVX-24 has the
potential to become the "standard of care." This statement implies an expectation of
regulatory approval and is inappropriate given the length of time and uncertainty with
respect to securing marketing approval.
Our Pipeline, page 3
2.Please remove your statement that you believe that your preclinical study results may be
predictive of clinical trial results based on your use of the same rabbit model used to
develop each of the PCVs approved to date.  It is not appropriate to imply that success in

 FirstName LastNameGrant E. Pickering
 Comapany NameSutroVax, Inc.
 November 7, 2019 Page 2
 FirstName LastName
Grant E. Pickering
SutroVax, Inc.
November 7, 2019
Page 2
animal models may result in success in humans.
3.Please expand to state whether you have received any feedback from the FDA as to
whether they would accept your intended approach of seeking regulatory approval based
on a demonstration of non-inferiority to the standard of care rather than on clinical field
efficacy studies.
Our Strategy, page 4
4.We note your disclosure that your strategy is to "rapidly advance" SVX-24 through IND-
enabling activities, clinical development and regulatory approval. Please revise this
statement and any similar disclosure to remove any implication that you will be successful
in commercializing your product candidates in a rapid or accelerated manner as such
statements are speculative.
Risk Factors Summary, page 5
5.We note several statements in the prospectus, including in a risk factor, regarding
pursuing a streamlined approach to regulatory approval of your vaccines based on how
other vaccines have obtained regulatory approval.  Please add a risk factor to this section
to make it clear that there can be no assurance that your intended approach will be
sufficient for regulatory approval or that regulators will not require field efficacy trials
or longer trials with more participants than you currently anticipate.
Implications of Being an Emerging Growth Company, page 7
6.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,
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 66
7.We note your disclosure that you intend to use a portion of the proceeds to fund the
clinical and ongoing development of your vaccine candidates. Please specifically disclose
how far you expect the proceeds from the offering to allow you to proceed in the
development of each of these candidates.
Business
Drawbacks for Current PCVs, page 102
8.Please make the disclosure under the charts in Figure 4 and Figure 5 on page 103 more
legible.

 FirstName LastNameGrant E. Pickering
 Comapany NameSutroVax, Inc.
 November 7, 2019 Page 3
 FirstName LastName
Grant E. Pickering
SutroVax, Inc.
November 7, 2019
Page 3
Intellectual Property, page 118
9.Please specify to which of your product candidates your pending and current patents
relate.
Amended and Restated Agreement with Sutro Biopharma, page 119
10.We note your disclosure that royalties are payable until the later of the expiration of the
last valid claim in the licensed patents or 10 years after the first commercial sale.  Please
specify when the licensed patents are expected to expire.
University of California, San Diego License Agreement, page 120
11.We note your disclosure that royalties are payable until expiration of the last licensed
patent. Please specify when the current last licensed patent is expected to expire.
Principal Stockholders, page 156
12.We note your disclosure regarding certain individuals who share or may be deemed to
share investment and dispositive power over the shares held by certain entities.  It is not
clear whether those are the sole individuals who have voting and investment control.  In
that regard, please revise your disclosure to identify all of the natural person or
persons who have voting and investment control of the shares held by Abingworth
Bioventures VI, LP, Longitude Venture Partners II, L.P., and TPG Growth IV Switcheroo,
L.P.
Description of Capital Stock, page 158
13.We note that you refer shareholders to, in part, the relevant provisions of the Delaware
General Corporation Law. It is not appropriate to qualify your disclosure by reference to
information that is not included in the filing or filed as an exhibit. Please revise
accordingly.
General
14.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.

 FirstName LastNameGrant E. Pickering
 Comapany NameSutroVax, Inc.
 November 7, 2019 Page 4
 FirstName LastName
Grant E. Pickering
SutroVax, Inc.
November 7, 2019
Page 4
            You may contact Michael Fay at 202-551-3812 or Al Pavot at 202-551-3738 if you have
questions regarding comments on the financial statements and related matters.  Please contact
Ada D. Sarmento at 202-551-3798 or Mary Beth Breslin at 202-551-3625 with any other
questions.
Sincerely,
Division of Corporation Finance
Office of Life Sciences
cc:       Robert W. Phillips, Esq.