United States securities and exchange commission logo

                            January 7, 2021

       Laurence Reid, Ph.D.
       President and Chief Executive Officer
       Decibel Therapeutics, Inc.
       1325 Boylston Street, Suite 500
       Boston, MA 02215

                                                        Re: Decibel
Therapeutics, Inc.
                                                            Draft Registration
Statement on Form S-1
                                                            Submitted December
11, 2020
                                                            CIK No. 0001656536

       Dear Dr. Reid:

              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

             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 submitted December 11, 2020

       Overview, page 1

   1.                                                   Please revise the
"Overview" section on page 1 to highlight that your gene therapy
                                                        programs are
       Gene Therapies for Congenital, Monogenic Hearing Loss, page 2

   2.                                                   We note your statement
here that "DB-OTO enabled a robust restoration of hearing" as
                                                        well as similar
statements elsewhere in the prospectus where you describe your product
                                                        candidates as
"result[ing] in robust regeneration of hair cells." Given the
                                                        early stage of
development, and your statements that your results in your preclinical
 Laurence Reid, Ph.D.
Decibel Therapeutics, Inc.
January 7, 2021
Page 2
         studies may not be indicative of results obtained in later trials,
these statements are overly
         speculative and inappropriate. Please remove these statements from the
descriptions of
         your product candidates.
Collaboration with Regeneron, page 4

3.       We note that you are developing DB-OTO, AAV.103 and AAV.104 with
Regeneron. We
         also note your disclosure on page 92 that you potentially owe certain
royalty payments to
         Regeneron with respect to DB-ATO. Please update your disclosure on
page 4 to identify
         DB-ATO as a product candidate that you are developing with Regeneron
or otherwise
Our Pipeline, page 5

4.       Please revise the pipeline table here and on page 113 to include
individual columns for
         each of the three phases of clinical development (i.e., include
separate columns for phases
         2 and 3). In addition, we note the inclusion of your Discovery program
in the pipeline
         table. Given the status of development and the lack of disclosure
regarding this program
         in your business section, please explain why this program is
sufficiently material to your
         business to warrant inclusion in your pipeline table or remove.
Implications of Being an Emerging Growth Company, page 7

5.       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.

6.       Please expand footnote (1) to explain how you determined the number of
common shares
         included in your pro forma earnings per share related to the the
automatic conversion of
         your preferred stock. In this regard, it appears that the changes made
to the conversion
         terms of your Series A, B and C preferred stock subsequent to
September 30, 2020
         resulted in changes to the number of common stock issuable upon
conversion as disclosed
         on pages F-27 and F-52. Address this comment as it relates to footnote
(1) to your
         Selected Financial Data.
Our rights to develop and commercialize any product candidates are subject and
may in the
future be subject...,
FirstName             page 40 Reid, Ph.D.
7.          NameDecibel
       Please               Therapeutics,
               revise to identify         Inc.candidates that are or may be
subject to march-in
                                  the product
         7, 2021 Page 2
FirstName LastName
 Laurence Reid, Ph.D.
FirstName  LastNameLaurence Reid, Ph.D.
Decibel Therapeutics, Inc.
January    NameDecibel Therapeutics, Inc.
        7, 2021
Page 3 7, 2021 Page 3
FirstName LastName

8.       We note that you intend to use a portion of the net proceeds to fund
the development of
         your various gene therapy programs and DB-020. Please revise to
specify how far in the
         clinical development of the associated product candidates you expect
to reach with the net
         proceeds. In this regard, we note that you have a number of clinical
trials planned for the
         associated product candidates, namely DB-020, DB-OTO and DB-ATO.
Restructuring, page 95

9.       We note that the you terminated 45 full-time employees in connection
with your
         restructuring, which appears to be over half of the workforce. Please
update the disclosure
         to include a description of the magnitude of the reduction in force.
In addition, please
         include a brief description of the specific reason for the
         and consider including a specific risk factor discussion highlighting
the reorganization.
Critical Accounting Policies and Significant Judgement and Estimates
Stock-Based Compensation, page 105

10.      Once you have an estimated offering price or range, please explain to
us how you
         determined the fair value of the common stock underlying your equity
issuances and 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
         beneficial conversion features. In this regard, we note your December
grant of stock
         options to purchase 14 million shares of common stock to your
employees and
         consultants appears outside of your typical option grants during prior
periods. Please
         discuss with the staff how to submit your response.
BUSINESS, page 110

11.      We note your disclosure of certain preclinical study results
throughout this section and
         elsewhere in your draft registration statement. For example only, we
note your disclosure
         that you "have evaluated in several preclinical studies, including
dose-response studies,
         the dependence of OTOF expression and functional recovery on dosing
increments at one
         month-post DB-OTO infusion," but do not include material details
regarding the study
         specifics. Please describe additional material information about the
         including, the number of participants, the method by which the product
candidates were
         administered, the primary and secondary endpoints, if applicable, and
a discussion of any
         adverse events for each of your material preclinical studies to date.
 Laurence Reid, Ph.D.
FirstName  LastNameLaurence Reid, Ph.D.
Decibel Therapeutics, Inc.
January    NameDecibel Therapeutics, Inc.
        7, 2021
Page 4 7, 2021 Page 4
FirstName LastName
Diagnosis and Treatment of Hearing Loss, page 116

12.      We note your disclosure that an independent study looked at "Word
Recognition with
         Normal Hearing v. Cochlear Implants." Please disclose the source for
this information as
         well as the number of individuals studied.
Preclinical Safety, page 127

13.      We note your disclosure that based on pre-IND feedback from the FDA,
you are currently
         conducting preclinical studies to support your planned submission.
Please provide
         additional material details on the ongoing preclinical studies and
include details, such as,
         type of study, number of participants, primary and secondary
endpoints, if applicable, and
         anticipated completion date.
Clinical Trials, page 132

14.      We note your disclosure that, "DB-020 was well-tolerated with adverse
events generally
         mild to moderate." To the extent a serious adverse event has occurred,
please clearly
         disclose the event and the number of affected patients.
Intellectual Property, page 134

15.      We note your disclosure on the intellectual property protection you
have for DB-OTO and
         DB-020. Please expand your disclosure to include a discussion on the
intellectual property
         protection you have for DB-ATO.
License and Collaboration Agreement with Regeneron Pharmaceuticals, Inc., page

16.      Please revise to disclose the amounts paid to date and when the
royalty term is currently
         expected to expire. In addition, please revise your disclosure on the
royalty range to
         disclose a royalty range of not more than 10 percentage points.
License Agreements with The Regents of The University of California and the
University of
Florida Research Foundation, Incorporated, page 138

17.      Please disclose when the last of the patent rights licensed under the
         Licenses are scheduled to expire.
License Agreement with The Curators of the University of Missouri, page 140

18.      Please disclose the upfront fee and when the last of the patent rights
licensed under the
         University of Missouri License is scheduled to expire.
 Laurence Reid, Ph.D.
FirstName  LastNameLaurence Reid, Ph.D.
Decibel Therapeutics, Inc.
January    NameDecibel Therapeutics, Inc.
        7, 2021
Page 5 7, 2021 Page 5
FirstName LastName
Note 17. Subsequent Events
Amendment to the Regeneron Agreement, page F-37

19.      We note that you issued 10,000,000 shares of your Series C preferred
stock to Regeneron
         in consideration for its entry into the amendment to the Regeneron
Agreement. Please
         explain, with reference to authoritative literature, how you accounted
for this issuance,
         including the determination of fair value.
       You may contact Ibolya Ignat at 202-551-3636 or Jeanne Baker at
202-551-3691 if you
have questions regarding comments on the financial statements and related
matters. Please
contact Jason Drory at 202-551-8342 or Jeffrey Gabor at 202-551-2544 with any
other questions.


                                                              Division of
Corporation Finance
                                                              Office of Life
cc:      Stuart Falber, Esq.