SC 13D

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

Decibel Therapeutics, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

24343R106

(CUSIP Number)

OrbiMed Advisors LLC

OrbiMed Capital GP VIII LLC

OrbiMed Genesis GP LLC

OrbiMed Capital LLC

601 Lexington Avenue, 54th Floor

New York, NY 10022

Telephone: (212) 739-6400

(Name, Address and Telephone Number of Person Authorized to
Receive Notices and Communications)

February 17, 2021

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ☐

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See §240.13d-7(b) for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a Reporting Person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No.  24343R106

1	Names of Reporting Persons.                  OrbiMed Advisors LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions). (a) o (b) o
3	SEC Use Only
4	Source of Funds (See Instructions) AF
5	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)			o
6	Citizenship or Place of Organization                Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	Sole Voting Power             0
		8	Shared Voting Power                              4,061,774
		9	Sole Dispositive Power       0
		10	Shared Dispositive Power            4,061,774
11	Aggregate Amount Beneficially Owned by Each Reporting Person                  4,061,774
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)			o
13	Percent of Class Represented by Amount in Row (11)                     16.7%*
14	Type of Reporting Person (See Instructions)                    IA

* This percentage is calculated based upon 24,301,577 Shares outstanding of Decibel Therapeutics, Inc. (the “Issuer”), as set forth in the Issuer’s Rule 424(b)(4) Prospectus filed with the Securities and Exchange Commission (“SEC”) on February 12, 2021.

CUSIP No. 24343R106

1	Names of Reporting Persons.                    OrbiMed Capital GP VIII LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions). (a) o (b) o
3	SEC Use Only
4	Source of Funds (See Instructions)            AF
5	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)			o
6	Citizenship or Place of Organization                                Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	Sole Voting Power            0
		8	Shared Voting Power                 3,843,206
		9	Sole Dispositive Power              0
		10	Shared Dispositive Power              3,843,206
11	Aggregate Amount Beneficially Owned by Each Reporting Person              3,843,206
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)			o
13	Percent of Class Represented by Amount in Row (11)              15.8%*
14	Type of Reporting Person (See Instructions)              OO

* This percentage is calculated based upon 24,301,577 Shares outstanding of Decibel Therapeutics, Inc. (the “Issuer”), as set forth in the Issuer’s Rule 424(b)(4) Prospectus filed with the Securities and Exchange Commission (“SEC”) on February 12, 2021.

CUSIP No. 24343R106
1	Names of Reporting Persons.                OrbiMed Genesis GP LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions). (a) o (b) o
3	SEC Use Only
4	Source of Funds (See Instructions)                  AF
5	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)			o
6	Citizenship or Place of Organization                     Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	Sole Voting Power             0
		8	Shared Voting Power            218,568
		9	Sole Dispositive Power              0
		10	Shared Dispositive Power            218,568
11	Aggregate Amount Beneficially Owned by Each Reporting Person                  218,568
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)			o
13	Percent of Class Represented by Amount in Row (11)              0.9%*
14	Type of Reporting Person (See Instructions)               IA

* This percentage is calculated based upon 24,301,577 Shares outstanding of Decibel Therapeutics, Inc. (the “Issuer”), as set forth in the Issuer’s Rule 424(b)(4) Prospectus filed with the Securities and Exchange Commission (“SEC”) on February 12, 2021.

CUSIP No. 24343R106
1	Names of Reporting Persons.                OrbiMed Capital LLC
2	Check the Appropriate Box if a Member of a Group (See Instructions). (a) o (b) o
3	SEC Use Only
4	Source of Funds (See Instructions)                  AF
5	Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e)			o
6	Citizenship or Place of Organization                     Cayman Islands
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		7	Sole Voting Power             883,418
		8	Shared Voting Power
		9	Sole Dispositive Power              883,418
		10	Shared Dispositive Power
11	Aggregate Amount Beneficially Owned by Each Reporting Person                  883,418
12	Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions)			o
13	Percent of Class Represented by Amount in Row (11)              3.6%*
14	Type of Reporting Person (See Instructions)               OO

* This percentage is calculated based upon 24,301,577 Shares outstanding of Decibel Therapeutics, Inc. (the “Issuer”), as set forth in the Issuer’s Rule 424(b)(4) Prospectus filed with the Securities and Exchange Commission (“SEC”) on February 12, 2021.

Item 1.  Security and Issuer

This Schedule 13D (the “Statement”) relates to the common stock, par value $0.001 per share (the “Shares”), of Decibel Therapeutics, Inc., a corporation organized under the laws of Delaware (the “Issuer” ), with its principal executive offices located at 1325 Boylston Street, Suite 500, Boston, Massachusetts 02215. The Shares are listed on the NASDAQ Global Select Market under the ticker symbol “DBTX”. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.

On October 30, 2020, the Issuer effected a reverse stock split at ratio of 1:10 basis and, on February 5, 2021, the Issuer effected a reverse stock split at ratio of 1:5.3 basis (the “Reverse Stock Splits”). References in this Statement to number of Shares give effect to the Reverse Stock Splits.

On February 17, 2021, the Issuer completed its initial public offering pursuant to which the Issuer agreed to issue and sell to the participants 7,062,000 Shares (the “IPO” ). In addition, the Issuer granted the underwriters an option to purchase, at the public offering price less any underwriting discounts and commissions, up to an additional 1,059,300 Shares. The purchase price for each Share was $18.00. As a result of the IPO, the Issuer’s total number of outstanding Shares increased to 24,301,577.

Item 2.  Identity and Background

(a) This Schedule 13D is being filed by OrbiMed Advisors LLC (“OrbiMed Advisors”), OrbiMed Capital GP VIII LLC. (“GP VIII”), OrbiMed Genesis GP LLC (“Genesis GP”), and OrbiMed Capital LLC (“OrbiMed Capital”) (collectively, the “Reporting Persons”).

 (b) — (c), (f) GP VIII, a limited liability company organized under the laws of Delaware, is the general partner of a limited partnership, as more particularly described in Item 6 below.  GP VIII has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

Genesis GP, a limited liability company organized under the laws of Delaware, is the general partner of a limited partnership, as more particularly described in Item 6 below.  Genesis GP has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

OrbiMed Advisors, a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended, is the managing member of GP VIII and Genesis GP, as more particularly described in Item 6 below.  OrbiMed Advisors has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

OrbiMed Capital, a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended, is the investment adviser of certain entities as more particularly described in Item 6 below.  OrbiMed Capital has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022.

The directors and executive officers of OrbiMed Advisors, GP VIII, Genesis GP, and OrbiMed Capital are set forth on Schedules I, II, III, and IV, respectively, attached hereto.  Schedules I, II, III, and IV set forth the following information with respect to each such person:

(i)          name;

(ii)         business address;

(iii)        present principal occupation of employment and the name, principal business and address of any corporation or other organization in which such employment is conducted; and

(iv)        citizenship.

(d) — (e) During the last five years, neither the Reporting Persons nor any Person named in Schedules I through IV has been (i) convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3.  Source and Amount of Funds or Other Consideration

In November 2020 and February 2021, OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OrbiMed Private Investments VIII, LP (“OPI VIII”), as more particularly referred to in Item 6 below, caused OPI VIII to purchase 2,732,106 shares of Series D Preferred Stock of the Issuer (after giving effect to the Reverse Stock Splits). In connection with the IPO, shares of Series D Preferred Stock were subsequently converted (on the closing of the IPO) into Shares on a 1-for-1 basis.

In November 2020 and February 2021, OrbiMed Advisors and Genesis GP, pursuant to their authority under the limited partnership agreement of OrbiMed Genesis Master Fund, L.P. (“Genesis”), as more particularly referred to in Item 6 below, caused Genesis to purchase 218,568 shares of Series D Preferred Stock of the Issuer (after giving effect to the Reverse Stock Splits). In connection with the IPO, shares of Series D Preferred Stock were subsequently converted (on the closing of the IPO) into Shares on a 1-for-1 basis.

In November 2020 and February 2021, OrbiMed Capital, as the investment advisor to OrbiMed Partners Master Fund Limited (“OPM”), as more particularly referred to in Item 6 below, caused OPM to purchase 327,852 shares of Series D Preferred Stock of the Issuer (after giving effect to the Reverse Stock Splits). In connection with the IPO, shares of Series D Preferred Stock were subsequently converted (on the closing of the IPO) into Shares on a 1-for-1 basis.

On and prior to the close of February 17, 2021, OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OPI VIII to purchase 1,111,100 Shares in the IPO.

On and prior to the close of February 17, 2021, OrbiMed Capital, as the investment advisor to OPM, caused OPM to purchase 555,566 Shares in the IPO.

The source of funds for such purchases was the working capital of OPI VIII, Genesis, and OPM.

As a result of the transactions described in this Item 3, GP VIII, as the general partner of OPI VIII, may be deemed to be the beneficial owner of approximately 15.8% of the outstanding Shares. Genesis GP, as the general partner of Genesis, may be deemed to be the beneficial owner of 0.9% of the outstanding Shares. OrbiMed Advisors, as the managing member of OrbiMed GP and Genesis GP, may be deemed to be the beneficial owner of approximately 16.7% of the outstanding Shares. OrbiMed Capital, as the investment advisor to OPM, be deemed to be the beneficial owner of 3.6% of the outstanding Shares. None of the Reporting Persons have acquired or disposed of any additional Shares since February 17, 2021.

Item 4.  Purpose of Transaction

This statement relates to the acquisition of Shares by the Reporting Persons. The Shares acquired by the Reporting Persons were acquired for the purpose of making an investment in the Issuer and not with the intention of acquiring control of the Issuer’s business on behalf of the Reporting Persons’ respective advisory clients.

The Reporting Persons from time to time intend to review their investment in the Issuer on the basis of various factors, including the Issuer’s business, financial condition, results of operations and prospects, general economic and industry conditions, the securities markets in general and those for the Issuer’s Shares in particular, as well as other developments and other investment opportunities.  Based upon such review, the Reporting Persons will take such actions in the future as the Reporting Persons may deem appropriate in light of the circumstances existing from time to time.  If the Reporting Persons believe that further investment in the Issuer is attractive, whether because of the market price of Shares or otherwise, they may acquire Shares or other securities of the Issuer either in the open market or in privately negotiated transactions.  Similarly, depending on market and other factors, the Reporting Persons may determine to dispose of some or all of the Shares currently owned by the Reporting Persons or otherwise acquired by the Reporting Persons either in the open market or in privately negotiated transactions.

Except as set forth in this Schedule 13D, the Reporting Persons have not formulated any plans or proposals which relate to or would result in:  (a) the acquisition by any person of additional securities of the Issuer or the disposition of securities of the Issuer, (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries, (c) a sale or transfer of a material amount of the assets of the Issuer or any of its subsidiaries, (d) any change in the present Board of Directors or management of the Issuer, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board, (e) any material change in the Issuer’s capitalization or dividend policy of the Issuer, (f) any other material change in the Issuer’s business or corporate structure, (g) any change in the Issuer’s charter or bylaws or other instrument corresponding thereto or other action which may impede the acquisition of control of the Issuer by any person, (h) causing a class of the Issuer’s securities to be deregistered or delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association, (i) a class of equity securities of the Issuer becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Act or (j) any action similar to any of those enumerated above.

Item 5.  Interest in Securities of the Issuer

 (a) — (b) As of the date of this filing, OPI VIII, a limited partnership organized under the laws of Delaware, holds 3,843,206 Shares, constituting approximately 15.8% of the issued and outstanding Shares.  GP VIII is the general partner of OPI VIII, pursuant to the terms of the limited partnership agreement of OPI VIII, and OrbiMed Advisors is the managing member of GP VIII, pursuant to the terms of the limited liability company agreement of GP VIII.  As a result, OrbiMed Advisors and GP VIII share power to direct the vote and disposition of the Shares held by OPI VIII and may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OPI VIII.  OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the Shares held by OPI VIII.

In addition, OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OPI VIII to enter into the agreements referred to in Item 6 below.

As of the date of this filing, Genesis, a limited partnership organized under the laws of the Cayman Islands, holds 218,568 Shares constituting approximately 0.9% of the issued and outstanding Shares.  Genesis GP is the general partner of Genesis, pursuant to the terms of the limited partnership agreement of Genesis, and OrbiMed Advisors is the managing member of Genesis GP, pursuant to the terms of the limited liability company agreement of Genesis GP.  As a result, OrbiMed Advisors and Genesis GP share power to direct the vote and disposition of the Shares held by Genesis and may be deemed, directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by Genesis. OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the Shares held by Genesis.

In addition, OrbiMed Advisors and Genesis GP, pursuant to their authority under the limited partnership agreement of Genesis, caused Genesis to enter into the agreements referred to in Item 6 below.

        As of the date of this filing, OPM, an exempted company under the laws of Bermuda, holds 883,418 Shares constituting 3.6% of the issued and outstanding Shares.  OrbiMed Capital is the investment advisor of OPM. As a result, OrbiMed Capital has the power to direct the vote and disposition of the Shares held by OPM and may be deemed directly or indirectly, including by reason of mutual affiliation, to be the beneficial owner of the Shares held by OPM.  OrbiMed Capital disclaims any beneficial ownership over the shares of the other Reporting Persons.  OrbiMed Capital exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the Shares held by OPM.

In addition, OrbiMed Capital, pursuant to their authority under the limited partnership agreement of OPM, caused OPM to enter into the agreements referred to in Item 6 below.

(c) Except as disclosed in Item 3, the Reporting Persons have not effected any transactions during the past sixty (60) days in any Shares.

(d) Not applicable.

(e) Not applicable.

Item 6.  Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, GP VIII is the general partner of OPI VIII, pursuant to the terms of the limited partnership agreement of OPI VIII.  Pursuant to this agreement and relationship, GP VIII has discretionary investment management authority with respect to the assets of OPI VIII. Such authority includes the power to vote and otherwise dispose of securities held by OPI VIII.  The number of outstanding Shares of the Issuer attributable to OPI VIII is 3,843,206 Shares. GP VIII, pursuant to its authority under the limited partnership agreement of OPI VIII, may be considered to hold indirectly 3,843,206 Shares.

In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, Genesis GP is the general partner of Genesis, pursuant to the terms of the limited partnership agreement of Genesis.  Pursuant to this agreement and relationship, Genesis GP has discretionary investment management authority with respect to the assets of Genesis. Such authority includes the power to vote and otherwise dispose of securities held by Genesis.  The number of outstanding Shares of the Issuer attributable to Genesis is 218,568. Genesis GP, pursuant to its authority under the limited partnership agreement of Genesis, may be considered to hold indirectly 218,568 Shares.

In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed Advisors is the managing member of GP VIII and Genesis GP, pursuant to the terms of the limited liability company agreements of GP VIII and Genesis GP. Pursuant to these agreements and relationships, OrbiMed Advisors and GP VIII have discretionary investment management authority with respect to the assets of OPI VIII.  OrbiMed Advisors and Genesis GP have discretionary investment management authority with respect to the assets of Genesis. Such authority includes the power of GP VIII to vote and otherwise dispose of securities held by OPI VIII and the power of Genesis GP to vote and otherwise dispose of the securities held by Genesis.  The number of outstanding Shares attributable to OPI VIII is 3,843,206 Shares and the number of Shares attributed to Genesis is 218,568 Shares.  OrbiMed Advisors, pursuant to its authority under the terms of the limited liability company agreements of OrbiMed GP and Genesis GP, may also be considered to hold indirectly 4,061,774 Shares.

OrbiMed Capital is the investment advisor to OPM. OrbiMed Capital may be deemed to have voting and investment power over the securities held by OPM. Such authority includes the power of OrbiMed Capital to vote and otherwise dispose of securities held by OPM.  The number of outstanding Shares attributable to OPM is 883,418 Shares. OrbiMed Capital, as the investment advisor to OPM, may also be considered to hold indirectly 883,418 Shares.

Peter Thompson (“Thompson”), an employee of OrbiMed Advisors, is a member of the Board of Directors of the Issuer and, accordingly, OrbiMed Advisors, Genesis GP, GP VIII, and OrbiMed Capital may have the ability to affect and influence control of the Issuer. From time to time, Thompson may receive stock options or other awards of equity-based compensation pursuant to the Issuer’s compensation arrangements for non-employee directors. Pursuant to an agreement with OrbiMed Advisors and GP VIII Thompson is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors and GP VIII, which will in turn ensure that such securities or economic benefits are provided to OPI VIII.

Investors’ Rights Agreement

In addition, OPI VIII, Genesis, OPM, and certain other stockholders of the Issuer entered into a Third Amended and Restated Investors’ Rights Agreement with the Issuer (the “Investors’ Rights Agreement”), dated as of November 2, 2020. Pursuant to the Investors’ Rights Agreement and subject to the terms and conditions therein, the parties agreed that:

Demand Registration Rights

At any time beginning six months following the date of the effective date of the registration statement of the IPO, the holders of at least 40% of the registrable securities then outstanding of the Issuer may make a written request that the Issuer register some or all of their registrable securities, subject to certain specified conditions and exceptions, including that at least 40% of the registrable securities be registered and that the aggregated gross offering price of such offering must exceed $5 million. The Issuer is required to use commercially reasonable efforts to effect the registration and will pay all registration expenses, other than underwriting discounts and commissions, related to any demand registration. The Issuer is not obligated to effect more than two of these registrations.

Piggyback Registration Rights

Whenever the Issuer proposes to file a registration statement under the Securities Act, other than with respect to certain excluded registrations, OPI VIII, Genesis, and OPM will be entitled to notice of the registration and have the right, subject to limitations that the underwriters may impose on the number of Shares included in the registration, to include the Shares held by them in the registration.

Form S-3 Registration Rights

At any time after the Issuer is qualified to file a registration statement on Form S-3 under the Securities Act, and subject to limitations and conditions specified in the Investors’ Rights Agreement, holders of at least 25% of the registrable securities then outstanding may make a written request that the Issuer prepare and file a registration statement on Form S-3 covering their Shares, so long as the aggregate price to the public equal or exceeds $3 million. The Issuer is not obligated to effect more than two of these Form S-3 registrations in any 12-month period.

Lock-Up Agreement

Pursuant to the Investors’ Rights Agreement, OPI VIII, Genesis, and OPM agreed that they will not, during the period ending 180 days after the date of the IPO (the “Lock-Up Period” ), directly or indirectly (1) sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any Shares or securities convertible into or exercisable or exchangeable for Shares with respect to which they have or have acquired the power of disposition or (2) enter into any swap or other agreement that transfers, in whole or in part, the economic risk of ownership of any such Shares.

After the Lock-Up Period expires, GP VIII’s, Genesis’, and OPM’s Shares will be eligible for sale in the public market, subject to any applicable limitations under Rule 144 under the Securities Act, and other applicable U.S. securities laws.

The foregoing description of the Investors’ Rights Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Investors’ Rights Agreement, which is filed as Exhibits 2 and incorporated herein by reference.

Item 7.  Material to Be Filed as Exhibits

Exhibit	Description
1.	Joint Filing Agreement among OrbiMed Advisors LLC, OrbiMed Capital GP VIII LLC, OrbiMed Genesis GP LLC, and OrbiMed Capital LLC.
2.	Third Amended and Restated Investors’ Rights Agreement by and among the Issuer and each of the signatories thereto, dated as of November 2, 2020 (incorporated by reference to Exhibit 4.2 to the Issuer’s Registration Statement on Form S-1 (SEC 333-253247), filed with the SEC on January 22, 2021).

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: March 1, 2021

ORBIMED ADVISORS LLC
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member
ORBIMED CAPITAL GP VIII LLC
By:	ORBIMED ADVISORS LLC, its managing member
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member of OrbiMed Advisors LLC
ORBIMED GENESIS GP LLC
By:	ORBIMED ADVISORS LLC, its managing member
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member of OrbiMed Advisors LLC
ORBIMED CAPITAL LLC
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member

SCHEDULE I

The names and present principal occupations of each of the executive officers and directors of OrbiMed Advisors LLC are set forth below. Unless otherwise noted, each of these persons is a United States citizen and has a business address of 601 Lexington Avenue, 54th Floor, New York, NY 10022.

Name	Position with Reporting Person	Principal Occupation
Carl L. Gordon	Member	Member OrbiMed Advisors LLC
Sven H. Borho German and Swedish Citizen	Member	Member OrbiMed Advisors LLC
Jonathan T. Silverstein	Member	Member OrbiMed Advisors LLC
W. Carter Neild	Member	Member OrbiMed Advisors LLC
Geoffrey C. Hsu	Member	Member OrbiMed Advisors LLC
C. Scotland Stevens	Member	Member OrbiMed Advisors LLC
David P. Bonita	Member	Member OrbiMed Advisors LLC
Trey Block	Chief Financial Officer	Chief Financial Officer OrbiMed Advisors LLC

SCHEDULE II

The business and operations of OrbiMed Capital GP VIII LLC are managed by the executive officers and directors of its managing member, OrbiMed Advisors LLC, set forth on Schedule I attached.

SCHEDULE III

The business and operations of OrbiMed Genesis GP LLC are managed by the executive officers and directors of its managing member, OrbiMed Advisors LLC, set forth on Schedule I attached.

SCHEDULE IV

The names and present principal occupations of each of the executive officers and directors of OrbiMed Capital LLC are set forth below. Unless otherwise noted, each of these persons is a United States citizen and has a business address of 601 Lexington Avenue, 54th Floor, New York, NY 10022.

Name	Position with Reporting Person	Principal Occupation
Carl L. Gordon	Member	Member OrbiMed Capital LLC
Sven H. Borho German and Swedish Citizen	Member	Member OrbiMed Capital LLC
Jonathan T. Silverstein	Member	Member OrbiMed Capital LLC
W. Carter Neild	Member	Member OrbiMed Capital LLC
Geoffrey C. Hsu	Member	Member OrbiMed Capital LLC
C. Scotland Stevens	Member	Member OrbiMed Capital LLC
David P. Bonita	Member	Member OrbiMed Capital LLC
Trey Block	Chief Financial Officer	Chief Financial Officer OrbiMed Capital LLC

EXHIBIT INDEX

Exhibit	Description
1.	Joint Filing Agreement among OrbiMed Advisors LLC, OrbiMed Capital GP VIII LLC, OrbiMed Genesis GP LLC, and OrbiMed Capital LLC.
2.	Third Amended and Restated Investors’ Rights Agreement by and among the Issuer and each of the signatories thereto, dated as of November 2, 2020 (incorporated by reference to Exhibit 4.2 to the Issuer’s Registration Statement on Form S-1 (SEC 333-253247), filed with the SEC on January 22, 2021).

EX-99.1

Exhibit 1

JOINT FILING AGREEMENT

The undersigned hereby agree that the Statement on Schedule 13D, dated March 1, 2021, with respect to the common stock of Decibel Therapeutics, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the undersigned agrees to be responsible for the timely filing of this Statement, and for the completeness and accuracy of the information concerning itself contained therein. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the 1^st day of March 2021.

ORBIMED ADVISORS LLC
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member
ORBIMED CAPITAL GP VIII LLC
By:	ORBIMED ADVISORS LLC, its managing member
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member of OrbiMed Advisors LLC
ORBIMED GENESIS GP LLC
By:	ORBIMED ADVISORS LLC, its managing member
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member of OrbiMed Advisors LLC
ORBIMED CAPITAL LLC
By:	/s/ Jonathan T. Silverstein
	Name: Jonathan T. Silverstein
	Title: Member