UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

(Rule 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.    )

Filed by the Registrant  ☒                            Filed by a Party other than the Registrant  ☐

Check the appropriate box:

UNUM THERAPEUTICS INC.Cogent Biosciences, Inc.

(Exact nameName of registrantRegistrant as specifiedSpecified in its charter)Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box)all boxes that apply):

UNUM THERAPEUTICS INC.

200 Cambridge Park Drive, Suite 3100

Cambridge,275 Wyman Street, 3rd Floor, Waltham, Massachusetts 0214002451

NOTICE OF 2019THE 2023 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON JUNE 7, 2023

To be held June 18, 2019the Stockholders of Cogent Biosciences, Inc.:

Notice is hereby given that the 2019Cogent Biosciences, Inc. (the “Company”) will hold its 2023 Annual Meeting of Stockholders or(the “Annual Meeting”) on Wednesday, June 7, 2023, at 9:00 a.m. Eastern Time. The Annual Meeting of Unum Therapeutics Inc.will be a virtual meeting conducted exclusively online via live audio webcast at www.virtualshareholdermeeting.com/COGT2023. The Annual Meeting will be held on June 18, 2019 at 8:00 a.m. Eastern Time at AC Hotel Boston Cambridge, Alewife A Meeting Space, 10 Acorn Park Drive, Cambridge, Massachusetts 02140. The purpose offor the Annual Meeting isfollowing purposes, as more fully described in the following:accompanying proxy statement (the “Proxy Statement”):

The proposal for the election of directors relates solely to the election of class I directors nominated by the Board of Directors.

Directors has fixed April 10, 2023 as the record date. Only Unum Therapeutics Inc. stockholders of record at the close of business on April 22, 2019,that date will be entitled to notice of, and to vote at, the Annual Meeting andor any adjournment or postponement thereof.

WeInstructions for accessing the virtual Annual Meeting are pleased to take advantage of Securities and Exchange Commission rules that allow companies to furnish their proxy materials overprovided in the Internet. We are mailing to our stockholders a Notice of Internet Availability of Proxy Materials, or Notice, insteadStatement. In the event of a paper copy of our proxy materials and our 2018 Annual Report to Stockholders,technical malfunction or 2018 Annual Report. The Notice contains instructions on how to access those documents and to cast your vote via the Internet. The Notice also contains instructions on how to request a paper copy of our proxy materials and our 2018 Annual Report. This process allows us to provide our stockholders with the information they need on a more timely basis, while reducing the environmental impact and lowering the costs of printing and distributing our proxy materials.

Your vote is important. Whether or not you are able to attendother situation that the meeting in person,chair determines may affect the ability of the Annual Meeting to satisfy the requirements for a meeting of stockholders to be held by means of remote communication under the Delaware General Corporation Law, or that otherwise makes it is important that your shares be represented. To ensure that your vote is recorded promptly, please vote as soon as possible, even if you planadvisable to attendadjourn the Annual Meeting, the meeting by submitting your proxy viachair or secretary will convene the Internetmeeting at 10:00 a.m. Eastern Time on the date specified above and at the Company’s address listedspecified above solely for the purpose of adjourning the meeting to reconvene at a date, time and physical or virtual location announced by the meeting chair or secretary. Under either of the foregoing circumstances, we will post information regarding the announcement on the proxy card or by signing, dating and returningInvestors page of the proxy card.Company’s website at https://investors.cogentbio.com/.

Cambridge, Massachusetts

April 30, 2019

Table of ContentsTABLE OF CONTENTS

LEGAL MATTERS

Important Notice Regarding the Availability of Proxy Materials for the 2023 Annual Meeting of Stockholders to Be Held on June 7, 2023. The Proxy Statement and Annual Report for the year ended December 31, 2022 are available at www.proxyvote.com.

Website References. Website references throughout this document are inactive textual references and provided for convenience only, and the content on the referenced websites is not incorporated herein by reference and does not constitute a part of the Proxy Statement.

i

UNUM THERAPEUTICS INC.

200 Cambridge Park Drive, Suite 3100

Cambridge,275 Wyman Street, 3rd Floor, Waltham, Massachusetts 0214002451

PROXY STATEMENT

FOR THE 20192023 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD JUNE 18, 2019QUESTIONS AND ANSWERS ABOUT THE PROXY MATERIALS AND VOTING

ThisWhat Is the Purpose of These Proxy Materials?

We are making these proxy statement contains information aboutmaterials available to you in connection with the 2019solicitation of proxies by the Board of Directors (the “Board”) of Cogent Biosciences, Inc. (“we,” “us,” “our” or the “Company”) for use at the 2023 Annual Meeting of Stockholders or the Annual Meeting, of Unum Therapeutics Inc., which will(the “Annual Meeting”) to be held virtually on Wednesday, June 18, 20197, 2023 at 8:9:00 a.m. Eastern Time, at AC Hotel Boston Cambridge, Alewife A Meeting Space, 10 Acorn Park Drive, Cambridge, Massachusetts 02140. The board of directors of Unum Therapeutics Inc. is using this proxy statement to solicit proxies for use at the Annual Meeting. In this proxy statement, the terms “Unum,” “we,” “us,” and “our” refer to Unum Therapeutics Inc. The mailing address of our principal executive offices is Unum Therapeutics Inc., 200 Cambridge Park Drive, Suite 3100, Cambridge, Massachusetts 02140.

All properly submitted proxies will be voted in accordance with the instructions contained in those proxies. If no instructions are specified, the proxies will be voted in accordance with the recommendation of our board of directors with respect to each of the matters set forth in the accompanying Notice of Meeting. You may revoke your proxyor at any other time before it is exercised at the meeting by giving our corporate secretary written noticefollowing adjournment or postponement thereof. You are invited to that effect.

We made this proxy statement and our Annual Report to Stockholders for the fiscal year ended December 31, 2018 available to stockholders on May 2, 2019.

We are an “emerging growth company” under applicable federal securities laws and therefore permitted to conform with certain reduced public company reporting requirements. As an emerging growth company, we provideparticipate in this proxy statement the scaled disclosure permitted under the Jumpstart Our Business Startups Act of 2012 (the JOBS Act), including the compensation disclosures required of a “smaller reporting company,” as that term is defined in Rule 12b-2 promulgated under the Securities Exchange Act of 1934, as amended (the Exchange Act). In addition, as an emerging growth company, we are not required to conduct votes seeking approval, on an advisory basis, of the compensation of our named executive officers or the frequency with which such votes must be conducted. We will remain an “emerging growth company” until the earliest of (i) the last day of the fiscal year following the fifth anniversary of our initial public offering in June 2018; (ii) the last day of the fiscal year in which our total annual gross revenue is equal to or more than $1.07 billion; (iii) the date on which we have issued more than $1 billion in nonconvertible debt during the previous three years; or (iv) the date on which we are deemed to be a large accelerated filer under the rules of the Securities and Exchange Commission. Even after we are no longer an “emerging growth company,” we may remain a “smaller reporting company.”

Important Notice Regarding the Availability of Proxy Materials for

the Annual Meeting and to vote on the proposals described in this Proxy Statement. The proxy materials are first being made available to our stockholders on or about April 25, 2023.

Why Did I Receive a Notice of StockholdersInternet Availability?

Pursuant to be Held on June 18, 2019:

This proxy statement and our 2018 Annual Report to Stockholders are

available for viewing, printing and downloading at www.edocumentview.com/UMRX

A copy of our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, as filed with theU.S. Securities and Exchange Commission (SEC), except for exhibits, will be furnished without charge to any stockholder upon written request to Unum Therapeutics Inc., 200 Cambridge Park Drive, Suite 3100, Cambridge, Massachusetts 02140, Attention: Corporate Secretary. This proxy statement and our Annual Report on Form 10-K for(“SEC”) rules, we are furnishing the fiscal year ended December 31, 2018 are also available on the SEC’s website at www.sec.gov.

UNUM THERAPEUTICS INC.

PROXY STATEMENT

FOR THE 2019 ANNUAL MEETING OF STOCKHOLDERS

GENERAL INFORMATION

When are this proxy statement and the accompanying materials scheduled to be sent to stockholders?

We have elected to provide access to our proxy materials to our stockholders primarily via the Internet. Accordingly, on or about May 2, 2019, we will beginInternet instead of mailing printed copies. This process allows us to expedite our stockholders’ receipt of proxy materials, lower the costs of printing and mailing the proxy materials and reduce the environmental impact of our Annual Meeting. If you received a Notice of Internet Availability of Proxy Materials or Notice. Our proxy materials, including the Notice of 2019 Annual Meeting of Stockholders, this proxy statement and the accompanying proxy card or, for shares held in street name (i.e. held for your account by a broker or other nominee)(the “Notice”), a voting instruction form, and the 2018 Annual Report to Stockholders, or 2018 Annual Report,you will be mailed or made available to stockholders on the Internet on or about the same date.

Why did Inot receive a Notice of Internet Availability of Proxy Materials instead of a full set of proxy materials?

Pursuant to rules adopted by the Securities and Exchange Commission, or SEC, for most stockholders, we are providing access to our proxy materials over the Internet rather than printing and mailing our proxy materials. We believe following this process will expedite the receipt of such materials and will help lower our costs and reduce the environmental impact of our annual meeting materials. Therefore, the Notice was mailed to holders of record and beneficial owners of our common stock starting on or about May 2, 2019. The Notice provides instructions as to how stockholders may access and review our proxy materials, including the Notice of 2019 Annual Meeting of Stockholders, this proxy statement, the proxy card and our 2018 Annual Report, on the website referred to in the Notice or, alternatively, how to request that aprinted copy of the proxy materials including a proxy card, be sent to them by mail.unless you request one. The Notice also provides voting instructions.instructions on how to access the proxy materials for the Annual Meeting via the Internet, how to request a printed set of proxy materials and how to vote your shares.

Why Are We Holding a Virtual Annual Meeting?

We have adopted a virtual meeting format for the Annual Meeting to provide a consistent experience to all stockholders regardless of geographic location. We believe this expands stockholder access, improves communications and lowers our costs while reducing the environmental impact of the meeting. In addition,structuring our virtual Annual Meeting, our goal is to enhance rather than constrain stockholder participation in the meeting, and we have designed the meeting to provide stockholders with the same rights and opportunities to participate as they would have at an in-person meeting.

Who Can Vote?

Only stockholders of record may request to receive the proxy materials in printed form by mail or electronically bye-mail on an ongoing basis for future stockholder meetings. Please note that, while our proxy materials are available at the website referenced in the Notice, and our Notice of 2019 Annual Meeting of Stockholders, this proxy statement and our 2018 Annual Report are available on our website, no other information contained on either website is incorporated by reference in or considered to be a part of this proxy statement.

Who is soliciting my vote?

Our Board of Directors, or the Board of Directors, is soliciting your vote for the Annual Meeting.

When is the record date for the Annual Meeting?

The record date for determination of stockholders entitled to vote at the Annual Meeting is the close of business on April 22, 2019.

How many votes can be cast by all stockholders?

There were 30,118,82210, 2023 (the “Record Date”) are entitled to notice of the Annual Meeting and to vote on the proposals described in this Proxy Statement. At the close of business on the Record Date, 70,946,790 shares of our common stock par value $0.001 per share, outstandingwere issued and outstanding.

What Is the Difference between Holding Shares as a Registered Stockholder and as a Beneficial Owner?

Registered Stockholder: Shares Registered in Your Name

If your shares of common stock are registered directly in your name with our transfer agent, Computershare Trust Company, N.A., you are considered to be, with respect to those shares of common stock, the registered stockholder, and these proxy materials are being sent directly to you by us.

Beneficial Owner: Shares Registered in the Name of a Broker, Fiduciary or Custodian

If your shares of common stock are held by a broker, fiduciary or custodian, you are considered the beneficial owner of shares of common stock held in “street name,” and these proxy materials are being forwarded to you from that broker, fiduciary or custodian.

How Can I Participate in the Virtual Annual Meeting?

Stockholders of record as of the close of business on April 22, 2019, all of whichthe Record Date are entitled to participate in and vote with respect to all matters to be acted upon at the Annual Meeting. Each stockholderTo participate in the Annual Meeting, including to vote, ask questions and view the list of registered stockholders as of the Record Date during the meeting, stockholders of record should go to the meeting website at www.virtualshareholdermeeting.com/COGT2023, enter the 16-digit control number found on your proxy card or Notice, and follow the instructions on the website. If your shares are held in street name and your voting instruction form or Notice indicates that you may vote those shares through www.proxyvote.com, then you may access, participate in and vote at the Annual Meeting with the 16-digit access code indicated on that voting instruction form or Notice. Otherwise, stockholders who hold their shares in street name should contact their bank, broker or other nominee (preferably at least five days before the Annual Meeting) and obtain a “legal proxy” in order to be able to attend, participate in or vote at the Annual Meeting.

We will endeavor to answer as many stockholder-submitted questions as time permits that comply with the Annual Meeting rules of conduct. We reserve the right to edit profanity or other inappropriate language and to exclude questions regarding topics that are not pertinent to meeting matters or Company business. If we receive substantially similar questions, we may group such questions together and provide a single response to avoid repetition.

The meeting webcast will begin promptly at 9:00 a.m. Eastern Time. Online check-in will begin approximately 15 minutes before then, and we encourage you to allow ample time for check-in procedures. If you experience technical difficulties during the check-in process or during the meeting, please call the number listed on the meeting website for technical support. Additional information regarding the rules and procedures for participating in the Annual Meeting will be set forth in our meeting rules of conduct, which stockholders can view during the meeting at the meeting website.

What Am I Voting on?

The proposals to be voted on at the Annual Meeting are as follows:

How Does the Board Recommend That I Vote?

The Board recommends that you vote your shares “FOR” each director nominee in Proposal 1 and “FOR” Proposals 2 and 3.

What If Another Matter Is Properly Brought before the Annual Meeting?

As of the date of filing this Proxy Statement, the Board knows of no other matters that will be presented for consideration at the Annual Meeting. If any other matters are properly brought before the Annual Meeting, it is the intention of the persons named as proxies in the proxy card to vote on such matters in accordance with their best judgment.

How Many Votes Do I Have?

Each share of common stock is entitled to one vote foron each shareproposal to be voted on at the Annual Meeting.

What Does It Mean If I Receive More Than One Set of our common stockProxy Materials?

If you receive more than one set of proxy materials, your shares may be registered in more than one name or held by such stockholder. Nonein different accounts. Please cast your vote with respect to each set of ourproxy materials that you receive to ensure that all of your shares of undesignated preferred stock were outstanding as of April 22, 2019.are voted.

How doDo I vote?Vote?

Even if you plan to attend the Annual Meeting, we recommend that you also submit your vote as early as possible in advance so that your vote will be counted if you later decide not to, or are unable to, virtually attend the Annual Meeting.

In PersonRegistered Stockholder: Shares Registered in Your Name

If you are athe registered stockholder, of record, you may vote in person at the Annual Meeting. We will give you a ballot when you arrive. If you hold your shares through a bankonline during the virtual Annual Meeting (see “How Can I Participate in the Virtual Annual Meeting?” above) or broker and wish to voteby proxy in person at the meeting, you must obtain a valid proxy from the firm that holds your shares.

By Proxy

If you do not wish to vote in person or will not be attendingadvance of the Annual Meeting you may vote by proxy. You can vote by proxy over the Internet by following the instructions provided in the Notice,(at www.proxyvote.com) or, if you requested printedpaper copies of the proxy materials, by mail, you can votecompleting and mailing a proxy card or by mailing your proxy as describedtelephone (at (800) 690-6903).

Beneficial Owner: Shares Registered in the proxy materials. In orderName of a Broker, Fiduciary or Custodian

If you are the beneficial owner, you may vote your shares online during the virtual Annual Meeting (see “How Can I Participate in the Virtual Annual Meeting?” above) or you may direct your broker, fiduciary or custodian how to be counted, proxies submitted by Internet must be received by the cutoff time of 11:59 p.m. Eastern Time on June 17, 2019. Proxies submitted by mail must be received before the startvote in advance of the Annual Meeting.Meeting by following the instructions they provide.

What Happens If I Do Not Vote?

Registered Stockholder: Shares Registered in Your Name

If you completeare the registered stockholder and submit your proxy beforedo not vote in one of the Annual Meeting, the persons named as proxies will vote the shares represented by your proxy in accordance with your instructions. If you submit a proxy without giving voting instructions,ways described above, your shares will not be voted in the manner recommended by the Board of Directors on all matters presented in this proxy statement, and as the persons named as

proxies may determine in their discretion with respect to any other matters properly presented at the Annual Meeting. You may also authorize another person or persons to act for you as proxy in a writing, signed by you or your authorized representative, specifying the details of those proxies’ authority. The original writing must be given to each of the named proxies, although it may be sent to them by electronic transmission if, from that transmission, it can be determined that the transmission was authorized by you.

If any other matters are properly presented for consideration at the Annual Meeting including, among other things, considerationand will not be counted toward the quorum requirement.

Beneficial Owner: Shares Registered in the Name of a motion to adjournBroker, Fiduciary or Custodian

If you are the Annual Meeting to another time or place (including, without limitation, for the purpose of soliciting additional proxies), the persons named in your proxybeneficial owner and acting thereunder will have discretion to vote on those matters in accordance with their best judgment. We do not currently anticipate that any other matters will be raised at the Annual Meeting.

How do I revoke my proxy?

You may revokedirect your proxy by (1) following the instructions on the Notice and entering a new vote by mail that we receive before the start of the Annual Meetingbroker, fiduciary or over the Internet by the cutoff time of 11:59 p.m. Eastern Time on June 17, 2019, (2) attending and voting at the Annual Meeting (although attendance at the Annual Meeting will not in and of itself revoke a proxy), or (3) by filing an instrument in writing revoking the proxy or another duly executed proxy bearing a later date with our Corporate Secretary. Any written notice of revocation or subsequent proxy card must be received by our Corporate Secretary prior to the taking of the vote at the Annual Meeting. Such written notice of revocation or subsequent proxy card should be hand delivered to our Corporate Secretary or sent to our principal executive offices at Unum Therapeutics Inc., 200 Cambridge Park Drive, Suite 3100, Cambridge, Massachusetts 02140, Attention: Corporate Secretary.

If a broker, bank, or other nominee holds your shares, you must contact such broker, bank, or nominee in order to find outcustodian how to change your vote.

How is a quorum reached?

Our Amended and Restated Bylaws, or bylaws, provide that a majority of the shares entitled to vote, present in person or represented by proxy, will constitute a quorum for the transaction of business at the Annual Meeting.

Under the General Corporation Law of the State of Delaware, shares that are voted “abstain” or “withheld” and broker“non-votes” are counted as present for purposes of determining whether a quorum is present at the Annual Meeting. If a quorum is not present, the meeting may be adjourned until a quorum is obtained.

How is the vote counted?

Under our bylaws, any proposal other than an election of directors is decided by a majority of the votes properly cast for and against such proposal, except where a larger vote is required by law or by our Amended and Restated Certificate of Incorporation, or certificate of incorporation, or bylaws. Abstentions and broker“non-votes” are not included in the tabulation of the voting results on any such proposal and, therefore, do not have an impact on such proposals. A broker“non-vote” occurs when a nominee holding shares for a beneficial owner does not vote on a particular proposal because the nominee does not have discretionary voting power with respect to that item, and has not received instructions from the beneficial owner.

If your shares are held in “street name” by a brokerage firm, your brokerage firm is required to vote your shares, according to your instructions. If you do not give instructions to your brokerage firm, the brokerage firmbroker, fiduciary or custodian will stillonly be able to vote your shares with respect to certain “discretionary” items, but willproposals considered to be “routine.” Your broker, fiduciary or custodian is not be allowedentitled to vote your shares with respect to“non-discretionary”non-routine” items. Proposal No. 1proposals, which we refer to as a “broker non-vote.” Whether a proposal is aconsidered routine or “non-discretionary”non-routine item. Ifis subject to stock exchange rules and final determination by the stock exchange. Even with respect to routine matters, some brokers are choosing not to exercise discretionary voting authority. As a result, we urge you do not instructto direct your broker, fiduciary or custodian how to vote your shares on all proposals to ensure that your vote is counted.

What If I Sign and Return a Proxy Card or Otherwise Vote but Do Not Indicate Specific Choices?

Registered Stockholder: Shares Registered in Your Name

The shares represented by each signed and returned proxy will be voted at the Annual Meeting by the persons named as proxies in the proxy card in accordance with respect to this proposal,the instructions indicated on the proxy card. However, if you are the registered stockholder and sign and return your broker may notproxy card without giving specific instructions, the persons named as proxies in the proxy card will vote for this proposal, and those votesyour shares in accordance with the recommendations of the Board. Your shares will be counted astoward the quorum requirement.

Beneficial Owner: Shares Registered in the Name of a Broker, Fiduciary or Custodian

If you are the beneficial owner and do not direct your broker,“non-votes.” Proposal No. 2 is considered fiduciary or custodian how to be a discretionary item, andvote your brokerage firmshares, your broker, fiduciary or custodian will only be able to vote your shares with respect to proposals considered to be “routine.” Your broker, fiduciary or custodian is not entitled to vote your shares with respect to “non-routine” proposals, resulting in a broker non-vote with respect to such proposals.

Can I Change My Vote after I Submit My Proxy?

Registered Stockholder: Shares Registered in Your Name

If you are the registered stockholder, you may revoke your proxy at any time before the final vote at the Annual Meeting in any one of the following ways:

Your last submitted vote is the one that will be counted.

Beneficial Owner: Shares Registered in the Name of a Broker, Fiduciary or Custodian

If you are the beneficial owner, you must follow the instructions you receive from your broker, fiduciary or custodian with respect to changing your vote.

What Is the Quorum Requirement?

The holders of a majority of the shares of common stock outstanding and entitled to vote at the Annual Meeting must be present at the Annual Meeting, either virtually or represented by proxy, to constitute a quorum. A quorum is required to transact business at the Annual Meeting.

Your shares will be counted toward the quorum only if you submit a valid proxy (or a valid proxy is submitted on this proposal evenyour behalf by your broker, fiduciary or custodian) or if it does not receive instructions from you.you attend the Annual Meeting virtually and vote. Abstentions and broker non-votes will be counted toward the quorum requirement. If there is no quorum, the chairman of the Annual Meeting or the holders of a majority of shares of common stock virtually present at the Annual Meeting, either personally or by proxy, may adjourn the Annual Meeting to another time or date.

ToHow Many Votes Are Required to Approve Each Proposal and How Are Votes Counted?

Our Board has appointed our Chief Financial Officer to serve as the Inspector of Elections to count the votes cast at the Annual Meeting.

Proposal 1: Election of Directors

A nominee will be elected as a director at the director nominated via Proposal No. 1 must receiveAnnual Meeting if the nominee receives a plurality of the votes cast “FOR” his or her election. “Plurality” means that the individuals who receive the highest number of votes cast “FOR” are elected as directors. Broker non-votes, if any, and entitled to votevotes that are withheld will not be counted as votes cast on the proposal, meaning that the director nominees receiving the most votesmatter and will be elected. Shares voting “withheld” have no effect on the outcome of the election. Stockholders do not have cumulative voting rights for the election of directors.

Proposal 2: Approval of an Amendment and Restatement of the Amended and Restated 2018 Stock Option and Incentive Plan

The majority of votes cast on the proposal is required for approval of Proposal 2. Abstentions and broker non-votes, if any, will not be counted as votes cast on the matter and will have no effect on the outcome of the matter.

Proposal 3: Ratification of Independent Registered Public Accounting Firm Selection

The majority of votes cast on the proposal is required for approval of Proposal 3. Abstentions and broker non-votes, if any, will not be counted as votes cast on the matter and will have no effect on the outcome of the matter.

Who pays the costIs Paying for soliciting proxies?This Proxy Solicitation?

We are making this solicitation and will pay the entire costcosts associated with the solicitation of preparingproxies, including the preparation, assembly, printing and distributing the Notice and our proxy materials and soliciting votes. If you choose to accessmailing of the proxy materials, any solicitation by telephone or vote overother electronic means and any in-person solicitation. We may also reimburse brokers, fiduciaries or custodians for the Internet, you are responsible for any Internet access charges that you may incur. Our officers and employees may, without compensation other than their regular compensation, solicit proxies through further mailings, personal conversations, facsimile transmissions,e-mails, or otherwise. We have hired Computershare Inc.cost of forwarding proxy materials to beneficial owners of shares of common stock held in “street name.”

Alliance Advisors, LLC has been retained to assist us in thesoliciting proxies for a fee of $12,500 plus distribution of proxy materialscosts and the solicitation of votes described above. Proxy solicitation expenses thatother expenses. Our employees, officers and directors may also solicit proxies, but we will not pay include thoseadditional compensation for preparation, mailing, returning, and tabulating the proxies.

How may stockholders submit matters for consideration at an annual meeting?

The required notice must be in writing and received by our corporate secretary at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversaryany of the preceding year’s annual meeting. However, in the event that the date of the annual meeting is advanced by more than 30 days, or delayed by more than 60 days, from the first anniversary of the preceding year’s annual meeting, or if no annual meeting were held in the preceding year, a stockholder’s notice must be so received no earlier than the 120th day prior to such annual meeting and not later than the close of business on the later of (A) the 90th day prior to such annual meeting and (B) the tenth day following the day on which notice of the date of such annual meeting was mailed or public disclosure of the date of such annual meeting was made, whichever first occurs.    

In addition, any stockholder proposal intended to be included in the proxy statement for the next annual meeting of our stockholders in 2020 must also satisfy the requirements of SEC Rule14a-8 under the Securities Exchange Act of 1934, as amended, or the Exchange Act, and be received not later than January 2, 2020. If the date of the annual meeting is moved by more than 30 days from the date contemplated at the time of the previous year’s proxy statement, then notice must be received within a reasonable time before we begin to print and send proxy materials. If that happens, we will publicly announce the deadline for submitting a proposal in a press release or in a document filed with the SEC.these services.

How canCan I knowFind out the voting results?Voting Results?

We planexpect to announce preliminary voting results at the Annual Meeting andMeeting. Final voting results will publish final resultsbe published in a Current Report on Form 8-K to be filed with the SEC within four business days followingafter the Annual Meeting.

PROPOSAL NO. 1 –1: ELECTION OF CLASS I DIRECTORS

Our board of directors currently consists of six members. In accordance with our Bylaws, the terms of our certificate of incorporation and bylaws, our boardBoard has fixed the number of directors is divided into three classes, class I, class II and class III, with members of each class serving staggered three-year terms. The members ofconstituting the classes are divided as follows:

Upon the expiration of the term of a class of directors, directors in that class will be eligible to be elected for a new three-year term at the annual meeting of stockholders in the year in which their term expires.

The directorships expiring this year are Class I directorships, currently filled by Liam Ratcliffe, M.D., Ph.D. and Robert Perez. Dr. Ratcliffe and Mr. Perez, who have served as a directors since 2015 and 2018, respectively, were not nominated forre-election and their terms as directors will expire at the Annual Meeting. In order to achieve a more equal balance of membership among the Company’s classes of directors in accordance with the Company’s amended and restated bylaws, it is intended that one of our current directors, Karen Ferrante, M.D., would move from Class II to Class I. To effect this, the board of directors, upon the recommendation of the nominating and corporate governance committee, has nominated Dr. Ferrante for election as a Class I director atseven. At the Annual Meeting, and Dr. Ferrante has provided a conditional notice of her intention to resign from Class II of the board of directors, which will only become effective if she is elected by our stockholders to Class I of the board of directors at the Annual Meeting. Assuming she is elected by the stockholders Dr. Ferrante’s designation will change from avote to elect the three Class II director nominees named in this Proxy Statement to Class I director followingserve until the 2026 Annual Meeting and she will serve as a directorof Stockholders or until the annual meeting of the stockholders in 2022 and until her successor istheir successors are duly elected and qualified or until hertheir earlier death, resignation or removal. IfOur Board has nominated Dr. FerranteChris Cain, Arlene M. Morris and Todd Shegog, each of whom is not elected bya current Class II director, for re-election to our stockholders to Class I of the board of directors at the Annual Meeting, her conditional resignation will not take effect,Board.

Our director nominees have indicated that they are willing and she will continueable to serve as a memberdirectors. However, if any of the board of directors in Class II.

The nominee is presently a director, and has indicated a willingness to continue to serve as a director, if elected. If the nomineethem becomes unable or, for good cause, unwilling to serve, however, the proxies may be voted for a substitute nominee selectedthe election of such other person as shall be designated by our boardBoard, or the Board may decrease the size of directors.the Board.

Information Regarding Director Nominees and Continuing Directors

Our certificateBoard is divided into three classes, with members of incorporation and bylaws provide that the authorized number of directors may be changed only by resolution of our board of directors. Our certificate of incorporation also provides that our directors may be removed onlyeach class holding office for cause by the affirmative vote of the holders of at leasttwo-thirds (2/3) of the outstanding shares then entitled to vote in an annual election of directors, and that any vacancy on our board of directors, including a vacancy resulting from an enlargement of our board of directors, may be filled only by vote of a majority of our directors then in office.

We have no formal policy regarding board diversity. Our priority in selection of board members is identification of members who will further the interests of our stockholders through their established record of professional accomplishment, their ability to contribute positively to the collaborative culture among board members, and their knowledge of our business and understanding of the competitive landscape.

Nominees for Election asstaggered three-year terms. There are currently two Class I Directordirectors, whose terms expire at the 2025 Annual Meeting of Stockholders; three Class II directors, who are up for election at this meeting for a term expiring at the 2026 Annual Meeting of Stockholders; and two Class III directors, whose terms expire at the 2024 Annual Meeting of Stockholders.

The following table identifiesBiographical and other information regarding our director nominee,nominees and setsdirectors continuing in office, including the primary skills and experiences considered by our Nominating and Corporate Governance Committee (the “Nominating Committee”) in determining to recommend them as nominees, is set forth her principal occupation and business experience during the last five years and her age as of April 22, 2019.below.

Class I Directors Continuing in Office

Karen Ferrante, M.D.Dr. Ferrante has served as a member of our board of directorsBoard since February 2018. Dr. Ferrante is a medical oncologist who served as the former Chief Medical Officer and Head of Research and Development of Tokai Pharmaceuticals, Inc.Inc (Nasdaq: TKAI), a publicly traded biopharmaceutical company where she developedfocused on developing treatments for prostate cancer and other hormonally driven diseases, betweenfrom April 2014 anduntil August 2016. From 2007 to July 2013, Dr. Ferrante held senior positions at Millennium Pharmaceuticals, Inc. and its parent company, Takeda Pharmaceutical Company Limited (NYSE: TAK), including Chief Medical Officer and most recently assubsequently, Oncology Therapeutic Area Head and Cambridge USA Site Head from May 2013 to July 2013. Dr. Ferrante previously held positions of increasing responsibility at Pfizer Global Research and Development and Bristol-Myers Squibb.Squibb Company (NYSE: BMY). Dr. Ferrante serves on the board of directors of Progenics Pharmaceuticals, Inc. (Nasdaq: PGNX), MacroGenics, Inc. (Nasdaq: MGNX), and Hutchinson China MediTechHUTCHMED (China) Limited (Nasdaq: HDM)HCM). Dr. Ferrante also served as a director of Progenics Pharmaceuticals, Inc. from 2014 until its acquisition by Lantheus Holdings, Inc. (Nasdaq: LNTH) in 2020 and Baxalta Inc., a publicly tradedpreviously publicly-traded global biopharmaceutical company, from July 2015 until its acquisition by

Shire Pharmaceuticalsplc in June 2016. She also served as an advisory board member for Kazia Therapeutics Limited (Nasdaq: KZIA) from 2016 until 2022 and Trillium Therapeutics Inc. (Nasdaq: TRIL) from 2020 until its acquisition by Pfizer in November 2021. Dr. Ferrante holds an M.D. from Georgetown University and a B.S. in chemistryChemistry and biologyBiology from Providence College.

We believe Dr. Ferrante’s qualificationsFerrante is qualified to sitserve on our boardBoard because of directors includes her extensive leadership, scientific, business and managerial experience in the biotechnology industry and her experience and expertise serving as a member of the board of directors of several biotechnology companies.

The proxies will be voted in favor of the above nominee unless a contrary specification is made in the proxy. The nominee has consented to serve as our directors if elected. However, if the nominee is unable to serve or for good cause will not serve as a director, the proxies will be voted for the election of such substitute nominee as our board of directors may designate.

The board of directors recommends voting “FOR” the election of Karen Ferrante, M.D. as a class I director, to serve for a three-year term ending at the annual meeting of stockholders to be held in 2022.

Directors Continuing in Office

The following table identifies our directors, and sets forth their principal occupation and business experience during the last five years and their ages as of April 22, 2019.

Class II Directors (Term Expires at 2020 Annual Meeting)Matthew E. Ros.

Bruce Booth, DPhil.has served as Chairman of our board of directors since February 2018 and as a member of our board of directors since October 2014. Dr. Booth joined Atlas Venture in 2005, and currently serves as a partner of Atlas Venture. Previously, from 2004 to 2005, Dr. Booth was a principal at Caxton Health Holdings L.L.C., a healthcare-focused investment firm, where he focused on the firm’s venture capital activities. Dr. Booth serves on the board of several public and privately held companies, including Miragen Therapeutics, Inc. (Nasdaq: MGEN) and Zafgen, Inc. (Nasdaq: ZFGN), among others. Dr. Booth holds a DPhil. in molecular immunology from Oxford University’s Nuffield Department of Medicine and a B.S. in biochemistry from Pennsylvania State University. Dr. Booth’s qualifications to sit on our board of directors include his extensive leadership, executive, managerial and business experience with life sciences companies, including experience in the formation, development, and business strategy of multiplestart-up companies in the life sciences sector.

Class III Directors (Term Expires at 2021 Annual Meeting)

Jörn AldagMr. Ros has served as a member of our board of directorsBoard since February 2016.July 2019. Mr. AldagRos has been theserved as Chief Executive Officer at Hookipa Pharmaand Director of Fore Biotherapeutics Inc. (formerly Hookipa Biotech AG), a clinical-stage precision oncology company, since June 2016.April 2022. Mr. AldagRos has more than 30 years of experience in global pharmaceutical and early-stage biotechnology companies, building and leading teams across sales, marketing, franchise strategy and business operations. Prior to joining Fore, Mr. Ros previously served as Chief Strategy and Business Officer of Epizyme, Inc. (Nasdaq: EPZM), a biopharmaceutical company, from September 2018 to October 2021. He served as Chief Operating Officer of Epizyme from May 2016 to September 2018. Prior to joining Epizyme, from September 2010 to May 2016, Mr. Ros served in increasing levels of responsibility at Sanofi S.A. (Nasdaq: SNY), a multinational pharmaceutical company, most recently as Chief Operating Officer/Global Head of the Chief Executive Officer at uniQure N.V. (formerly, Amsterdam Molecular Therapeutics N.V.)Oncology business unit from October 2009 to December 2015 and as an advisor to the board of uniQure N.V. from January 20162014 to May 2016. Prior to his tenure at uniQure N.V.,that role, Mr. Aldag wasRos served in the rare disease business of Genzyme Corporation, a Sanofi company, where he served as Vice President and Chief Executive OfficerFranchise Head of Evotec AGits Pompe disease unit from November 1997September 2012 to December 2008. Mr. Aldag2014, and also served as the Chairman of Molecular Partners AG, Zurich, Switzerland (SWIX:MOLN)Associate Vice President and Iniparib Global Brand Leader in Sanofi’s Oncology business unit from September 2010 to September 2012. From October 2007 to 2018.June 2010, Mr. Ros served at ARIAD Pharmaceuticals, Inc., a global oncology company, most recently as Senior Vice President, Commercial Operations. He co-founded G7 Therapeutics AGstarted his pharmaceutical career in 2014, which was acquired by Heptares Therapeutics Ltd.Bristol-Myers Squibb’s Oncology Division, serving in 2016. Mr. Aldagroles with increasing responsibility from 1990 to 2007. He received business degreesa B.S. from the Harvard BusinessState University of New York, College at Plattsburgh and completed the Executive Education Program in Finance and Accounting for the Non-Financial Manager at Wharton School (Advanced Management Program) in 1994 and fromof the European Business School (Diplom Betriebswirt) in 1982.University of Pennsylvania.

We believe Mr. Aldag’s qualificationsRos is qualified to sitserve on our boardBoard because of directors include his extensive leadership, executive, managerial and business experience with life sciences companies.

Charles Wilson,Class II Directors Nominees

Chris Cain, Ph.D.Dr. Cain has served as a member of our Chief Executive OfficerBoard since July 2020 and is a designee of Fairmount Funds Management LLC (“Fairmount”), a healthcare investment firm. Dr. Cain has served as Director of Research at Fairmount since March 2014 andApril 2020. From February 2019 to February 2020, Dr. Cain served as our President since January 2019. From 2008 until he joined Unum, Dr. Wilson was Vice President at Samsara BioCapital, a biotherapeutics-focused venture capital fund. Prior to that role, Dr. Cain worked at Apple Tree Partners, a life sciences-focused venture capital fund, from 2016 to January 2019, and Global Head of Strategic Alliances at the Novartis Institutes for BioMedical Research. In this role, heRA Capital Management, an investment management company, before that. Previously, Dr. Cain was responsible for partnering to support Novartis’ researcha writer and early development efforts through to clinical proof of concept. Dr. Wilson has held both scientific and business management roles in biotechnology, including asco-founder and Chief Technology Officer of Archemix between 2001 and 2008. Dr. Wilsoneditor at BioCentury Publications. He received a B.A. in Biology and Chemistry and an M.A. in Cell Biology from Bostonthe University of California, Santa Barbara and a Ph.D. in BiophysicsBiochemistry and Molecular Biology from the University of California, San Francisco. Dr. Wilson completed his post-doctoral training at Harvard University and Massachusetts General Hospital.

We believe that Dr. WilsonCain is qualified to serve on our boardBoard because of directors due to his extensive knowledge of our companyleadership, scientific, business and managerial experience in the life sciences sector.biotechnology industry.

Directors Not Nominated forRe-Election

The following table identifies our directors whose terms expire at the Annual Meeting and were not nominated by the nominating and corporate governance committee, and sets forth their principal occupation and business experience during the last five years and their ages as of April 22, 2019.

Liam Ratcliffe, M.D., Ph.D.Arlene M. Morris. Ms. Morris has served as a member of our boardBoard since July 2019. Ms. Morris has served as Chief Executive Officer of directorsWillow Advisors, a consultancy advising biotech companies on financing, strategy and business development, since June 2015. Dr. Ratcliffe isPreviously, she spent over a Managing Director at New Leaf Venture Partners where he is focused on biopharmaceutical investing. Dr. Ratcliffe joined New Leaf in September 2008. Dr. Ratcliffe was previously Senior Vice President and Development Head for Pfizer Neuroscience,decade leading public biotechnology companies. From 2012 to 2015, Ms. Morris served as well as Worldwide HeadChief Executive Officer of

Clinical Research and Development at Pfizer. Dr. Ratcliffe received his M.D. degree and Ph.D. degree in immunology from the University of Cape Town and his M.B.A. degree from the University of Michigan. Dr. Ratcliffe serves on the board of public companies, including Edge Therapeutics, Inc. (Nasdaq: EDGE) and Deciphera Syndax Pharmaceuticals Inc. (Nasdaq: DCPH)SNDX), a biopharmaceutical company focused on the development and commercialization of an epigenetic therapy for treatment-resistant cancers. Prior to this, she served as President and Chief Executive

Officer of Affymax Inc. (OTCMKTS: AFFY), a biotechnology company, where she led the company through the development of peginesatide (Omontys^®). He previouslyShe spent 15 years at Johnson & Johnson (NYSE: JNJ), a pharmaceutical company, in marketing, sales and senior level business development positions. Ms. Morris served on the board of Array Biopharmaceuticals,directors of Viveve Medical, Inc. (OTCMKTS: VIVE) from 2016 to 2022, Dimension Therapeutics, Inc. (Nasdaq: ARRY) (2012-2014). Dr. Ratcliffe’s term expires at the Annual MeetingDMTX) from 2015 to 2018 and heNeovacs, SA (Euronext: ALNEV) from 2011 to 2020. She was not nominated forre-election by our nominating and corporate governance committee.

Robert J. Perez has served asalso a memberdirector of our board of directors since February 2018. Mr. Perez is the managing partner of Vineyard Sound Advisors, a biopharmaceutical advisory firm. Mr. Perez is the former Chief Executive Officer of Cubist Pharmaceuticals,Biodel Inc., a publicpublicly traded specialty pharmaceutical development company, which was acquired by Merck & Company, Inc.from 2015 until its merger with Albireo Limited in January 2015. Mr. Perez joined Cubist in August 2003 as Senior Vice President, Sales and Marketing. He served as Executive Vice President and Chief Operating Officer from August 2007 to July 2012 and President and Chief Operating Officer from July 2012 to December 2014. Prior to joining Cubist, he served as Vice President of Biogen, Inc.’s CNS business unit. Mr. Perez2016. Ms. Morris is currently serves as a member of the board of directors of AMAG Pharmaceuticals,Palatin Technologies, Inc. (Nasdaq: AMAG), Cidara(NYSE: PTN) and Viridian Therapeutics, Inc. (Nasdaq: CDTX), SparkVRDN). She received a B.A. in Biology and Chemistry from Carlow College.

We believe Ms. Morris is qualified to serve on our Board because of her extensive leadership, executive, managerial and board experience within pharmaceutical and biotechnology industries.

Todd Shegog. Mr. Shegog has served as a member of our Board since February 2021. Mr. Shegog has more than 25 years of financial, operations, corporate strategy and compliance expertise in the biotechnology and pharmaceutical industries. He served as Senior Vice President and Chief Financial Officer of Forma Therapeutics, Inc. (Nasdaq: ONCE)FMTX), and Zafgen,a clinical-stage biopharmaceutical company, from September 2019 through its acquisition by Nova Nordisk in October 2022. Prior to Forma Therapeutics, Mr. Shegog served as Chief Financial Officer of Synlogic, Inc. (Nasdaq: ZFGN)SYBX), a clinical-stage biopharmaceutical company, where he directed the company’s financial strategy and management as well as facilities and information systems from September 2016 to September 2019. From April 2014 to August 2016, Mr. Shegog served as Senior Vice President and Chief Financial Officer at Forum Pharmaceuticals, Inc., an early-stage biopharmaceutical company, where he was responsible for finance, operations and information systems during their pursuit of innovative therapies for schizophrenia and Alzheimer’s disease. He also served as the Chief Financial Officer of Millennium Pharmaceuticals, Inc., now Takeda Oncology, where he was responsible for management of the company’s financial resources, corporate planning, financial reporting and compliance from 1998 to 2014. Mr. Shegog earned a directorB.S. in Electrical Engineering from Lafayette College and an M.B.A. from the Tepper School of Management at Carnegie Mellon University.

We believe Mr. Shegog is qualified to serve on our Board because of his financial expertise, extensive leadership, executive, managerial and business experience with life sciences companies.

Class III Directors Continuing in Office

Andrew Robbins. Mr. Robbins has served as our Chief Executive Officer, President, principal executive officer and a member of our Board since October 2020. Prior to joining Cogent, Mr. Robbins served as Chief Operating Officer at Array BioPharma Inc., a pharmaceutical company, from March 2015 through its acquisition by Pfizer Inc. (NYSE: PFE), a pharmaceutical company, in July 2019, after serving as its Senior Vice President, Commercial Operations from July 2012 to March 2015. From January 2007 to July 2012, Mr. Robbins held management positions at Hospira, Inc., a pharmaceutical and medical device company, including General Manager and Vice President of the U.S. Alternate Site business unit and Vice President of Corporate Development. Prior to Hospira, Mr. Robbins held commercial and leadership positions within Pfizer’s oncology unit. Additionally, Mr. Robbins currently serves on the boardsboard of certain private companies, including Vir Biotechnology,directors of Harpoon Therapeutics, Inc. (Nasdaq: HARP) and Akili Interactive Labs, Inc.Turmeric Acquisition Corporation (Nasdaq: TMPMU). Mr. Robbins holds an M.B.A. from the Kellogg School of Management, Northwestern University and a bachelor’s degree from Swarthmore College.

We believe Mr. Robbins is qualified to serve on our Board because of his extensive commercial, development and strategic leadership experience in the pharmaceutical industry.

Peter Harwin. Mr. Harwin has served as a member of our Board since July 2020 and is a designee of Fairmount. He alsois currently a managing member at Fairmount, a healthcare investment firm he co-founded in April 2016. Prior to Fairmount, Mr. Harwin served as a member of the boardinvestment team at Boxer Capital, LLC,

part of directors of Cubist from April 2014 until January 2015 and as a member ofthe Tavistock Group, based in San Diego. Mr. Harwin also serves on the board of directors of Flex Pharma,Viridian Therapeutics, Inc. (Nasdaq: FLKS)VRDN), Paragon Therapeutics, Inc. and Apogee Therapeutics, LLC. Mr. Harwin received his B.B.A. from Emory University.

We believe Mr. Harwin is qualified to serve on our Board because of his extensive leadership, executive, managerial and board experience within pharmaceutical and biotechnology industries.

Board Recommendation

The Board recommends a public biopharmaceutical company, from 2015 to January 2018. Mr. Perez isvote “FOR” the Founder and Chairman of Life Science Cares and has been a member of the Board of Trustees at The Dana Farber Cancer Institute, Inc. since January 2013. Mr. Perez received a B.S. in business from California State University, Los Angeles and an M.B.A. from the Anderson Graduate School of Management at the University of California, Los Angeles. Mr. Perez’s term expires at the Annual Meeting and he was not nominated forre-election by our nominating and corporate governance committee.

There are no family relationships between or among any of our directors or executive officers. The principal occupation and employment during the past five yearselection of each of the Class II director nominees set forth above.

PROPOSAL 2: APPROVAL OF AN AMENDMENT AND RESTATEMENT OF OUR AMENDED AND RESTATED 2018 STOCK OPTION AND INCENTIVE PLAN

Summary

Our Board is asking you to approve an amendment and restatement of the Cogent Biosciences, Inc. Amended and Restated 2018 Stock Option and Incentive Plan (the “2018 Plan”) to increase the number of shares reserved for issuance thereunder. If stockholders approve this proposal, the number of shares of our directorscommon stock that may be delivered pursuant to awards granted under the 2018 Plan will be increased by an additional 6,000,000 shares. There would be a corresponding increase in the number of shares that may be delivered pursuant to incentive stock options granted under the 2018 Plan (for clarity, such shares also count against, and are not in addition to, the aggregate share limit for the 2018 Plan).

On February 16, 2023, our Board of Directors approved the amendment and restatement of the 2018 Plan, including the proposed increase to the shares issuable thereunder, subject to stockholder approval.

We also maintain the Cogent Biosciences, Inc. 2020 Inducement Plan (the “Inducement Plan,” and together with the 2018 Plan, the “Plans”). As of March 31, 2023, (i) a total of 15,503,250 shares were then subject to outstanding options granted under the Plans, (ii) a total of up to 2,500,000 shares were then subject to outstanding and unvested performance-based restricted stock units (“PSUs”) granted under the 2018 Plan that are contingent upon stockholder approval of this proposal as discussed below under “Specific Benefits under the 2018 Plan,” (iii) 677,995 shares were available for new award grants under the Inducement Plan and (iv) 796,715 shares were available for new award grants under the 2018 Plan (without taking into account the 6,000,000 shares that would be added to the 2018 Plan if stockholders approve this proposal or the up to 2,500,000 shares subject to PSUs that are contingent on stockholder approval of this proposal). No other award types are outstanding under the Plans. As of March 31, 2023, the average weighted per share exercise price of all outstanding stock options granted under the Plans was carried$9.96 ($9.89 under the 2018 Plan only) and the weighted average remaining contractual term was 8.52 years (8.71 years under the 2018 Plan only). If stockholders approve this proposal, we currently expect the number of additional shares being requested for approval, combined with the evergreen provision in the 2018 Plan, will be sufficient to meet our expected needs through the first quarter of 2026 based on our historical grant practices and performance. If stockholders do not approve this proposal, we will continue to have the authority to grant awards under the 2018 Plan, but the proposed 6,000,000 share increase in each case exceptthe 2018 Plan share limit will not be effective and the PSUs covering up to 2,500,000 shares will be forfeited, both of which could result in a serious disruption of our compensation programs and will limit our ability to provide retention incentives to our executives and other employees. Equity awards are a significant component of total compensation for our executive officers and other employees and are vital to our ability to attract and retain outstanding and highly skilled individuals in the extremely competitive labor markets in which we must compete. If stockholders do not approve the proposal, we would need to grant cash and other non-equity rewards to these individuals. We believe that such alternative forms of compensation do not align employee interests with those of stockholders as specifically identified above,efficiently as equity-based awards, and we feel it is important to provide compensation that continues to effectively align employees with stockholders and which provides a corporation or organizationtotal compensation package that is notcompetitive with other companies. We strongly believe that the approval of this proposal is instrumental to our continued success.

Please see the discussion below under “Specific Benefits under the 2018 Plan” and “Aggregate Past Grants Under the 2018 Plan” for detailed information on certain awards that we granted that are contingent on stockholder approval of this proposal, as well as past awards granted under the Plan.

Award Burn Rate

The following table presents information regarding our net burn rate for the past three fiscal years, with average annual net burn rate over such three years being 7.3%. For this purpose, the “net burn rate” for any one particular fiscal year means the total number of shares of our common stock issuable upon exercise or payment,

as the case may be, of the equity-based awards granted by us in that fiscal year, less the total number of such shares canceled, terminated or forfeited in the fiscal year without the awards having become vested or paid, as the case may be, divided by our weighted average number of shares of common stock issued and outstanding during that particular fiscal year on an as-converted basis, including the conversion of Series A convertible preferred stock and the exercise of pre-funded warrants.

We currently expect that the additional shares requested for the 2018 Plan under this proposal (taking into account the PSUs that have been granted that are conditioned on stockholder approval of this proposal, as discussed above), along with the evergreen provision under the 2018 Plan, would provide us with flexibility to continue to grant equity-based awards through the first quarter of 2026, assuming a parent, subsidiarylevel of grants consistent with the number of equity-based awards granted historically and usual levels of shares becoming available for new awards as a result of forfeitures of outstanding awards throughout the projected period. However, this is only an estimate, in our management’s judgment, based on current circumstances. The total number of shares that are awarded under the 2018 Plan in any one year or other affiliatefrom year to year may change based on any number of us. There is no arrangementvariables, including, without limitation, the value of our common stock (since higher stock prices generally require that fewer shares be issued to produce awards of the same grant date fair value), changes in competitors’ compensation practices or understanding between anychanges in compensation practices in the market generally, changes in the number of our employees, changes in the number of our directors and officers, acquisition activity and the potential need to grant awards to new employees in connection with acquisitions, the need to attract, retain and incentivize key talent, the types of awards we grant, and how we choose to balance total compensation between cash and equity-based awards. The type and terms of awards granted may also change in any other personone year or persons pursuantfrom year to which heyear based on any number of variables, including, without limitation, changes in competitors’ compensation practices or she ischanges in compensation practices generally, and the need to be selected as a director.attract, retain and incentivize key talent.

There are no material legal proceedings to which any of our directors is a party adverse to us or any of our subsidiaries or in which any such person has a material interest adverse to us or our subsidiary.

Executive Officers Who Are Not DirectorsDilution

The following table identifiesshows the total number of shares of our executive officers,common stock that were (i) subject to outstanding stock options granted under the Plans, (ii) subject to outstanding and sets forth their current positions at Unumunvested PSUs that are subject to forfeiture if this proposal is not approved by stockholders, and their ages(iii) available for new award grants under the 2018 Plan, in each case, as of April 22, 2019.each of December 31, 2022 and March 31, 2023. In this Proposal 2, the number of

shares of our common stock subject to awards granted during any particular period or outstanding on any particular date is presented based on the actual number of shares of our common stock covered by those awards.

Seth Ettenberg, Ph.D. has served as

To help assess the potential dilutive impact of this proposal, the number of shares of our Chief Scientific Officer since September 2014. From 2005 until he joined Unum, Dr. Ettenberg served as Headcommon stock outstanding at the end of Novartis Oncology Biotherapeutics, Cambridge Site. Dr. Ettenberg is a cancer biologist and drug development scientist with experience building and leading teams in biotechnology and large pharmaceutical drug discovery settings. Dr. Ettenberg received his Ph.D. from the Uniform Services Universityeach of the Health Scienceslast three fiscal years and completed his post-doctoral trainingas of March 31, 2023 on an as-converted basis, including the conversion of Series A convertible preferred stock and the exercise of pre-funded warrants, is as follows: 65,408,906 shares outstanding at the National Cancer Institute.end of fiscal year 2020, 69,628,172 shares outstanding at the end of fiscal year 2021, 90,761,994 shares outstanding at the end of fiscal year 2022, and 90,812,850 shares outstanding as of March 31, 2023.

Michael Vasconcelles, M.D. has served asThe closing market price of our Chief Medical Officer since October 2015. From March 2012 until he joined Unum, Dr. Vasconcelles served as the Senior Vice President, Head, Oncology Therapy Area Unit at Takeda Pharmaceuticals, where hecommon stock on The Nasdaq Global Select Market on April 10, 2023 was accountable for the oncology research and development strategy and progression$10.68.

Our Board believes that approval of the oncology portfolio from candidate selection through life cycle managementamendment and a memberrestatement of the research2018 Plan, including the proposed increase to the shares reserved for issuance thereunder, will promote our interests and development executive committee. From 2000 until 2012, Dr. Vasconcelles served in several positions at Genzyme Corporationthose of our stockholders and Sanofi S.A., including Group Vice Presidentwill help us continue to be able to attract, motivate, retain and Global Therapeutic Area Head, Transplantreward persons important to our success. All members of our Board and Oncology. In this capacity, he was also a member of the Oncology Business Unit leadership team. Dr. Vasconcelles is a Clinical Instructor in Medicine at Harvard Medical School and a staff physician at the Dana-Farber Cancer Institute and Brigham & Women’s Hospital. Dr. Vasconcelles received his B.A. from Northwestern University and his M.D. from Northwestern University’s Feinberg School of Medicine.

Geoffrey Hodge has served as our Chief Technical Officer and Senior Vice President of Operations since July 2015. From 2003 and until he joined Unum, Mr. Hodge held several roles at GE Healthcare, the most recent of which was Bioprocess Technology Leader and prior to that Fast Trak Solutions Leader. Prior to GE Healthcare, Mr. Hodge wasa co-founder of Xcellerex where he served as its VP of Process Development & Manufacturing. During his tenure at Xcellerex, Mr. Hodge is the inventor of record on multiple technology patents. Mr. Hodge holds a B.A. in Biology from Colgate University and an M.S. in Biotechnology from Worcester

Polytechnic Institute.

The principal occupation and employment during the past five years of eachall of our executive officers was carried on,are eligible for awards under the 2018 Plan and thus have a personal interest in each case exceptthe approval of the proposed amendment and restatement of the 2018 Plan.

Board Recommendation

The Board recommends a vote “FOR” the increase to the shares reserved for issuance pursuant to our Amended and Restated 2018 Stock Option and Incentive Plan.

Summary Description of the 2018 Plan

The principal terms of the 2018 Plan are summarized below. The following summary is qualified in its entirety by the full text of the 2018 Plan, which appears as specifically identified above,Appendix A to this Proxy Statement and reflects the impact of the proposed increase in the shares reserved for issuance pursuant to the 2018 Plan in Section 3(a) thereof.

Purpose

The purpose of the 2018 Plan is to encourage and enable the officers, employees, non-employee directors and consultants of the Company and its subsidiaries upon whose judgment, initiative and efforts the Company largely depends for the successful conduct of its businesses to acquire a proprietary interest in the Company. It is anticipated that providing such persons with a corporationdirect stake in the Company’s welfare will help align their interests with those of the Company and its stockholders, thereby stimulating their efforts on the Company’s behalf and strengthening their desire to remain with the Company.

Administration

Our Compensation Committee administers the 2018 Plan (the “Administrator”). The Administrator has broad authority under the 2018 Plan including, without limitation, the authority:

No Repricing

In no case (except due to an adjustment to reflect a stock split, merger or other event referred to under “Adjustments” below, or any repricing that may be approved by stockholders) will the Administrator reduce the exercise price of outstanding stock options or stock appreciation rights or effect repricing through cancellation and re-grants or cancellation of stock options and stock appreciation rights in exchange for cash or other awards.

Eligibility

Persons eligible to receive awards under the 2018 Plan include our full or part-time officers and other employees, non-employee directors and consultants of the Company and its subsidiaries. As of March 31, 2023, approximately 146 of our officers and employees (including all of our named executive officers currently employed by us), each of our six non-employee directors and other individuals who provide services to us as consultants were considered eligible under the 2018 Plan. While consultants are generally considered eligible under the 2018 Plan to preserve our flexibility, over the last five years we have only granted equity awards under the 2018 Plan to the five members of our Scientific Advisory Board, plus one other individual who, at the time of grant of the awards, was neither employed by us, nor a member of our Board. We do not expect to grant any equity awards under the 2018 Plan to consultants who are not members of our Scientific Advisory Board in the future.

Authorized Shares and Limits on Awards

Assuming stockholders approve this proposal, subject to adjustment for certain dilutive events as provided in the 2018 Plan, the maximum number of shares of our common stock reserved and available for issuance under the 2018 Plan will be 19,085,985 (the “Initial Limit”), plus on January 1, 2024 and each January 1 thereafter, the number of shares of stock reserved and available for issuance under the 2018 Plan will be cumulatively increased by four percent of the number of shares of our common stock issued and outstanding on the immediately preceding December 31 or such lesser number determined by the Administrator. In addition, the shares of common stock underlying any awards under the 2018 Plan and under the Company’s previously outstanding

2015 Stock Incentive Plan that are forfeited, canceled, held back upon exercise of an option or settlement of an award to cover the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of common stock or otherwise terminated (other than by exercise) will be added back to the shares of common stock available for issuance under the 2018 Plan. Subject to such overall limitation, the maximum aggregate number of shares of common stock that may be issued in the form of incentive stock options will not exceed the Initial Limit as cumulatively increased each year. In the event the Company repurchases shares of common stock on the open market, such shares will not be added to the shares of common stock available for issuance under the 2018 Plan. The shares available for issuance under the 2018 Plan may be authorized but unissued shares of common stock or shares of common stock reacquired by the Company.

The value of all awards granted under the 2018 Plan and all other cash compensation paid by the Company to any non-employee director in any calendar year may not exceed $1,000,000. For the purpose of this limitation, the value of any award is its grant date fair value, as determined in accordance with Financial Accounting Standards Board Accounting Standards Codification Topic 718, Compensation – Stock Compensation (“ASC Topic 718”) or its successor provision but excluding the impact of estimated forfeitures related to service-based vesting provisions.

Types of Awards

The 2018 Plan authorizes incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights. A stock option is the right to purchase shares of our common stock at a future date at a specified price per share (the “exercise price”). The per share exercise price of an option generally may not be less than the fair market value of a share of our common stock on the date of grant. The maximum term of an option is ten years from the date of grant. An option may either be an incentive stock option or a non-qualified stock option. Incentive stock option benefits are taxed differently from non-qualified stock options, as described under “U.S. Federal Income Tax Consequences of Awards Under the 2018 Plan” below. Incentive stock options are also subject to more restrictive terms and are limited in amount by the Internal Revenue Code and the 2018 Plan. Incentive stock options may only be granted to employees.

A stock appreciation right is the right to receive payment of an amount equal to the excess of the fair market value of a share of our common stock on the date of exercise of the stock appreciation right over the base price of the stock appreciation right. The base price will be established by the Administrator at the time of grant of the stock appreciation right and generally may not be less than the fair market value of a share of our common stock on the date of grant. Stock appreciation rights may be granted in connection with other awards or independently. The maximum term of a stock appreciation right is ten years from the date of grant. Options and stock appreciation rights may be fully vested at grant or may be subject to time- and/or performance-based vesting requirements.

The other types of awards that may be granted under the 2018 Plan include, without limitation, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights that represent the right to receive credits based on cash dividends that would have been paid on the shares of stock specified in the right (or other award to which it relates) if such shares had been issued to and held by the grantee. Any awards under the 2018 Plan may be fully vested at grant or may be subject to time- and/or performance-based vesting requirements.

Assumption and Termination of Awards

The 2018 Plan provides that upon the effectiveness of a “sale event,” as defined in the 2018 Plan, an acquirer or successor entity may assume, continue or substitute outstanding awards under the 2018 Plan. To the extent that awards granted under the 2018 Plan are not assumed or continued or substituted by the successor entity, upon the effective time of the sale event, such awards under the 2018 Plan shall terminate. In the event of such termination, individuals holding options and stock appreciation rights will be permitted to exercise such options and stock appreciation rights (to the extent exercisable) within a specified period of time prior to the sale event. In addition, in connection with the termination of the 2018 Plan upon a sale event, we may make or provide for a cash payment to participants holding vested and exercisable options and stock appreciation rights

equal to the difference between the per share cash consideration payable to stockholders in the sale event and the exercise price of the options or stock appreciation rights and we may make or provide for a cash payment to participants holding other vested awards.

Transfer Restrictions

Subject to certain exceptions contained in the 2018 Plan, awards under the 2018 Plan generally are not transferable by the recipient other than by will or the laws of descent and distribution and are generally exercisable, during the recipient’s lifetime, only by the recipient. Any amounts payable or shares issuable pursuant to an award generally will be paid only to the recipient or the recipient’s beneficiary or legal representative. The Administrator has discretion, however, to establish written conditions and procedures for the transfer of awards to his or her immediate family members, to trusts for the benefit of such family members or to partnerships in which such family members are the only partners, provided that the transferee agrees in writing with the Company to be bound by all of the terms and conditions of the 2018 Plan and the applicable award. In no event may an award be transferred by a grantee for value.

Adjustments

As is customary in incentive plans of this nature, each share limit and the number and kind of shares available under the 2018 Plan and any outstanding awards, as well as the exercise or purchase prices of awards, and performance targets under certain types of performance-based awards, are subject to adjustment in the event of certain reorganizations, mergers, combinations, recapitalizations, stock splits, stock dividends or other similar events that change the number or kind of shares outstanding and extraordinary dividends or distributions of property to the stockholders.

Term

No awards may be granted under the 2018 Plan after the date that is not a parent, subsidiaryten years from the date of stockholder approval of the 2018 Plan.

Termination of or Changes to the 2018 Plan

Our Board may amend or discontinue the 2018 Plan, and our Compensation Committee may amend or cancel outstanding awards for purposes of satisfying changes in law or any other affiliate of us. There islawful purpose, but no arrangement or understanding between anysuch action may adversely affect rights under an award without the holder’s consent. Certain amendments to the 2018 Plan require the approval of our stockholders.

U.S. Federal Income Tax Consequences of Awards Under the 2018 Plan

The U.S. federal income tax consequences of the 2018 Plan under current federal law, which is subject to change, are summarized in the following discussion of the general tax principles applicable to the 2018 Plan. This summary is not intended to be exhaustive and, among other considerations, does not describe the deferred compensation provisions of Section 409A of the Internal Revenue Code to the extent an award is subject to and does not satisfy those rules, nor does it describe state, local or international tax consequences.

With respect to non-qualified stock options, we are generally entitled to deduct and the participant recognizes taxable income in an amount equal to the difference between the option exercise price and the fair market value of the shares at the time of exercise. With respect to incentive stock options, we are generally not entitled to a deduction (unless the employee sells the underlying shares upon exercise before the tax holding period) nor does the participant recognize income at the time of exercise, although the participant may be subject to the U.S. federal alternative minimum tax. Upon the sale or exchange of the shares more than two years after grant of an incentive stock option and one year after exercising an incentive stock option, any gain or loss will be treated as long-term capital gain or loss. If these holding periods are not satisfied, the optionee will recognize ordinary income and we will be entitled to a deduction at the time of sale or exchange equal to the difference

between the exercise price and the lower of (i) the fair market value of the shares at the date of the option exercise, or (ii) the sale price of the shares. A different rule for measuring ordinary income upon such a premature disposition may apply if the optionee is also an officer or director of the Company. Any gain or loss recognized on such a premature disposition of the shares in excess of the amount treated as ordinary income will be characterized as long-term or short-term capital gain or loss, depending on the holding period.

The current U.S. federal income tax consequences of other awards authorized under the 2018 Plan generally follow certain basic patterns: nontransferable restricted stock subject to a substantial risk of forfeiture results in income recognition equal to the excess of the fair market value over the price paid (if any) only at the time the restrictions lapse (unless the recipient elects to accelerate recognition as of the date of grant); bonuses, stock appreciation rights, cash and stock-based performance awards, dividend equivalents, restricted stock units and other types of awards are generally subject to tax at the time of payment; and compensation otherwise effectively deferred is taxed when paid. In each of the foregoing cases, we will generally have a corresponding deduction at the time the participant recognizes income.

If an award is accelerated under the 2018 Plan in connection with a “change in control” (as this term is used under the Internal Revenue Code), we may not be permitted to deduct the portion of the compensation attributable to the acceleration (“parachute payments”) if it exceeds certain threshold limits under the Internal Revenue Code (and certain related excise taxes may be triggered).

U.S. federal income tax law generally prohibits a publicly held company from deducting compensation paid to certain current or former officers that qualify as “covered employees” within the meaning of Section 162(m) of the Internal Revenue Code that exceeds $1 million during the tax year.

Specific Benefits Under the 2018 Plan

The Administrator has approved certain PSU awards under the 2018 Plan that are contingent on stockholder approval of this proposal. These grants are set forth in the following table. If stockholders do not approve this proposal, these grants will be forfeited, and we will not be able to grant the equity incentives we believe are necessary to provide retention incentives. The number of PSUs included in the table below assumes that “target” performance is achieved. A participant can generally receive between 0% and 200% of the target award based on achievement of specified stock price hurdles and development milestones over a three-year performance period ending in February 2026. PSUs generally vest, if at all, in a single tranche in February 2026.    

Awards Subject to Stockholder Approval of 2018 Plan Proposal

If the proposed amendments to the 2018 Plan had been in effect in fiscal year 2022, we expect that our award grants for fiscal year 2022 would not have been substantially different from those actually made in that year. For information regarding stock-based awards granted to our named executive officers and any other personduring fiscal year 2022, see “Executive Compensation.”

Aggregate Past Grants Under the 2018 Plan

Other than the contingent PSUs presented in the table above, the benefits that will be awarded or personspaid in the future under the 2018 Plan are not currently determinable; provided, however, that pursuant to which he was or isour outside director compensation policy, beginning in 2023, new non-employee directors are eligible to be selected as an executive officer.

There are no material legal proceedingsreceive a one-time stock option grant to which anypurchase 73,400 shares of our executive officers iscommon stock and continuing directors are eligible to receive, at the time of the Company’s annual meeting, a party adversestock option grant to uspurchase 36,700 shares of our common stock. As a result, we anticipate our non-employee directors will receive the foregoing grants, as applicable, subject to continued service through the grant date. Other than the foregoing, awards under the 2018 Plan are within the discretion of the Compensation Committee, and the Compensation Committee has not determined future awards or who might receive them. As of March 31, 2023, awards covering 13,681,245 shares of our subsidiary orcommon stock have been granted under the 2018 Plan. The following table shows information regarding the distribution of awards, including the contingent PSUs (at target), covering such shares as of such date among the persons and groups identified below. The closing market price of our common stock on The Nasdaq Global Select Market on April 10, 2023 was $10.68.

Registration

The Company intends to file with the SEC a registration statement on Form S-8 covering the new shares reserved for issuance under the 2018 Plan in which any such person has a material interest adverse to us or our subsidiary.the second half of 2023.

PROPOSAL NO. 2 –3: RATIFICATION OF THE APPOINTMENT OF PRICEWATERHOUSECOOPERS LLP

AS UNUM’S INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THESELECTION

FISCAL YEAR ENDING DECEMBER 31, 2019

Unum’s stockholders are being asked to ratify the appointment by the audit committee of the board of directors ofOur Audit Committee has selected PricewaterhouseCoopers LLP (“PwC”) as Unum’sthe Company’s independent registered public accounting firm for the fiscal year ending December 31, 2019. PricewaterhouseCoopers LLP has served2023. In this Proposal 3, we are asking stockholders to vote to ratify this selection. Representatives of PwC are expected to be present at the Annual Meeting. They will have the opportunity to make a statement, if they desire to do so, and are expected to be available to respond to appropriate questions from stockholders.

Stockholder ratification of the selection of PwC as Unum’sthe Company’s independent registered public accounting firm since 2015.

The audit committee is solely responsible for selecting Unum’s independent registered public accounting firm for the fiscal year ending December 31, 2019. Stockholder approvalauditor is not required to appoint PricewaterhouseCoopers LLPby law or our Bylaws. However, we are seeking stockholder ratification as Unum’s independent registered public accounting firm. However, the boarda matter of directors believes that submitting the appointment of PricewaterhouseCoopers LLP to the stockholders for ratification is good corporate governance.practice. If our stockholders fail to ratify the stockholders do not ratify this appointment,selection, the audit committee will reconsider whether to retain PricewaterhouseCoopers LLP. Ifits selection. Even if the selection of PricewaterhouseCoopers LLP is ratified, the audit committee, atin its discretion, may direct the appointmentselection of a different independent registered public accounting firmauditor at any time during the year if it decidesdetermines that such a change would be in the best interestinterests of Unumthe Company and itsour stockholders.

A representative of PricewaterhouseCoopers LLP isPwC has served as our independent auditor since 2015. The following table summarizes the audit fees billed and expected to be present at the Annual Meeting and will have an opportunity to make a statement if he or she desires to do so and to respond to appropriate questions from our stockholders.

Unum incurred the following fees from PricewaterhouseCoopers LLPbilled by PwC for the audit ofindicated fiscal years and the consolidated financial statements andfees billed by PwC for all other services providedrendered during the years ended December 31, 2018indicated fiscal years. All services associated with such fees were pre-approved by our Audit Committee in accordance with the “Pre-Approval Policies and 2017.Procedures” described below.

Audit Committee Pre-approval PolicyPre-Approval Policies and Procedures

Our audit committeeAudit Committee has adopted policies and procedures relating to the approval of all audit and non-audit services that are to be performed by our independent registered public accounting firm. This policy providesauditor in order to ensure that these services do not impair the auditor’s independence. In accordance with these policies and procedures, we will not engage our independent registered public accounting firmauditor to render audit or non-audit services unless the service is specifically approved in advance by our audit committeeAudit Committee or the engagement is entered into pursuant to the pre-approval procedure described below. The Audit Committee does not delegate its responsibility to approve services performed by the independent registered public accounting firm to any member of management.

From time to time, our audit committeeAudit Committee may pre-approve specified types of services that are expected to be provided to us by our independent registered public accounting firmauditor during the next 12 months. Any such pre-approval details the particular service or type of services to be provided and is also generally subject to a maximum dollar amount.

Report of the Audit Committee

The Audit Committee has reviewed and 2017 fiscal years, no services were provided to us by PricewaterhouseCoopers LLP other than in accordancediscussed the audited financial statements for the year ended December 31, 2022 with the pre-approval policiesCompany’s management and procedures described above.

The board of directors recommends voting “FOR” Proposal No. 2 to ratifywith PwC, the appointment of PricewaterhouseCoopers LLP as Unum’sCompany’s independent registered public accounting firmfirm. The Audit Committee has discussed with PwC the matters required to be discussed by the applicable standards of the Public Company Accounting Oversight Board (“PCAOB”) and the SEC. The Audit Committee has also received the written disclosures and the letter from PwC pursuant to applicable PCAOB requirements regarding its communications with the Audit Committee concerning independence, and the Audit Committee has discussed with PwC its independence. Based on the foregoing, the Audit Committee recommended to the Board that the audited consolidated financial statements be included in the Company’s Annual Report on Form 10-K for the fiscal year endingended December 31, 2019.

This report is provided by the following directors, who serve on the Audit Committee:

Todd Shegog (Chair)

Arlene M. Morris

Matthew E. Ros

Board Recommendation

The Board recommends a vote “FOR” the ratification of the selection of PwC to serve as our independent registered public accounting firm.

CORPORATE GOVERNANCE

Our business affairs are managed under the direction of our Board. Our Board has adopted a set of Corporate Governance Guidelines as a framework for the governance of the Company, which is posted on our website located at https://investors.cogentbio.com/, under “Corporate Governance.”

Board Composition

Director Nomination Process

Our nominating and corporate governance committeeThe Nominating Committee is responsible for, identifying individualsamong other things, overseeing succession planning for directors and building a qualified board to serve as directors, consistentoversee management’s execution of the Company’s strategy and safeguard the long-term interests of stockholders. In this regard, the committee is charged with criteria approved by our board,developing and recommending such personsBoard membership criteria to be nominatedthe Board for election asapproval, evaluating the composition of the Board annually to assess the skills and experience that are currently represented on the Board and the skills and experience that the Board may find valuable in the future, and identifying, evaluating and recommending potential director candidates.

In identifying potential candidates for Board membership, the Nominating Committee considers recommendations from directors, except where we are legally required by contract, law or otherwise to provide third parties with the right to nominate.

The process followed by our nominating and corporate governance committee to identify and evaluate director candidates includes requests to board membersstockholders, management and others, for recommendations, meetingsincluding, from time to time, third-party search firms to evaluate biographical information and background material relating toassist it in locating qualified candidates. Once potential director candidates and interviews of selected candidates by management, recruiters, members ofare identified, the committee, with the assistance of management, undertakes a vetting process that considers each candidate’s background, independence and our board. The qualifications, qualities and skills that our nominating and corporate governancefit with the Board’s priorities. As part of this vetting process, the committee, believes must be met by a committee-recommended nominee for a position on our board of directors are as follows:

The Nominating Committee seeks to balance the experiences, skills and corporate governance committee for consideration ascharacteristics represented on the Board and does not assign specific weight to any of these factors.

Board Diversity

In addition to the factors discussed above, the Board and the Nominating Committee actively seek to achieve a diversity of occupational and personal backgrounds on the Board. The Nominating Committee

considers a potential director candidate’s ability to contribute to the diversity of personal backgrounds on the Board, including with respect to gender, race, ethnic and national background, geography, age and sexual orientation. The Nominating Committee assesses its effectiveness in balancing these considerations in connection with its annual evaluation of the composition of the Board. In this regard, our current Board of seven directors includes two directors (28%) who self-identify as female and one director (14%) who self-identifies as a member of the LGBTQ+ community.

In accordance with Nasdaq’s board diversity listing standards, we are disclosing aggregated statistical information about our Board’s self-identified gender and racial characteristics and LGBTQ+ status as voluntarily confirmed to us by each of our directors.

Stockholder Recommendations for Directors

It is the Nominating Committee’s policy to consider written recommendations from stockholders for director candidates. The committee considers candidates recommended by our stockholders in the same manner as a candidate recommended by other sources. Any such proposalsrecommendations should be submitted to our corporate secretary at our principal executive offices no laterthe committee as described under “Stockholder Communications” not less than the close of business on the 90^th day nor earlier than the close of business on the 120th day120 days prior to theone-year anniversary of date on which the date ofCompany’s proxy statement was released to the precedingstockholders in connection with the previous year’s annual meeting and should include appropriate biographicalthe following information: (i) the name and background material to allowaddress of record of the nominating and corporate governance committee to properly evaluate the potential director candidate and the number of shares of our stock beneficially owned bystockholder; (ii) a representation that the stockholder proposingis a record holder of the candidate. Stockholder proposals should be addressed to Unum Therapeutics Inc., 200 Cambridge Park Drive, Suite 3100, Cambridge, Massachusetts 02140, Attention: Corporate Secretary. Assuming that biographical and background material has been provided onCompany’s securities, or if the stockholder is not a timely basisrecord holder, evidence of ownership in accordance with our bylaws, any recommendations receivedRule 14a-8(b)(2) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”); (iii) the name, age, business and residential address, educational background, current principal occupation or employment, and principal occupation or employment for the preceding five full fiscal years of the proposed director candidate; (iv) a description of the qualifications and background of the proposed director candidate which addresses the minimum qualifications and other criteria for Board membership approved by the Board from stockholders will be evaluatedtime to time and set forth in the same manner as potential nomineescharter of the Nominating Committee; (v) a description of all arrangements or understandings between the stockholder and the proposed bydirector candidate; (vi) the nominating and corporate governance committee. If our boardconsent of directors determinesthe proposed director candidate (1) to nominate a stockholder-recommended candidate and recommends his or her election, then his or her name will be included on ournamed in the proxy card forstatement relating to the nextCompany’s annual meeting of stockholders. See “Stockholder Proposals”stockholders and (2) to serve as a director if elected at such annual meeting; and (vii) any other information regarding the proposed director candidate that is required to be included in a proxy statement filed pursuant to the rules of the SEC.

Board Leadership Structure

Mr. Harwin serves as our independent Chairman while Mr. Robbins serves as our President and CEO. Our Corporate Governance Guidelines provide our Board with the flexibility to combine or separate the positions of

Chairman and CEO. Currently, the Board believes that the roles of Chairman and CEO should be separate and that the Chairman should be an independent director as this structure enables our independent Chairman to oversee corporate governance matters and our CEO to focus on leading the Company’s business.

The independent directors have the opportunity to meet in executive sessions without management present at every regular Board meeting and at such other times as may be determined by the Chairman. The purpose of these executive sessions is to encourage and enhance communication among the independent directors.

The Board believes that its programs for overseeing risk, as described under “Board Risk Oversight,” would be effective under a discussionvariety of submitting stockholder proposals.leadership frameworks. Accordingly, the Board’s risk oversight function did not significantly impact its selection of the current leadership structure.

Director Independence

Applicable Nasdaq Stock Market LLC, or Nasdaq,listing rules require a majority of a listed company’s board of directors to be comprised of independent directors within one year of listing. In addition, the Nasdaq rules require that, subject to specified exceptions, each member of a listed company’s audit, compensation and nominating and corporate governance committees be independent and that audit committee members also satisfy independence criteria set forth in Rule 10A-3 under the Exchange Act and that compensation committee members satisfy independence criteria set forth in Rule 10C-1 under the Exchange Act. Under applicable Nasdaq rules, a director will only qualify as an “independent director” if,who, in the opinion of the listed company’s board of directors, that person doesdo not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. In orderSubject to be considered independent for purposes of Rule 10A-3, aspecified exceptions, each member of an audit committee of a listed company may not, other than incompany’s audit, compensation and nominating committees must be independent, and audit and compensation committee members must satisfy additional independence criteria under the Exchange Act.

Our Board undertook a review of its composition and the independence of each director. Based upon information requested from and provided by each director concerning his or her capacity as a member of the audit committee, the board of directors, or any other board committee, accept, directly or indirectly, any consulting, advisory, or other compensatory fee from the listed company or any of its subsidiaries or otherwise be an affiliated person of the listed company or any of its subsidiaries. In addition, in affirmatively determining the independence of any director who will serve on a company’s compensation committee, Rule 10C-1 under the Exchange Act requires that a company’s board of directors must consider all factors specifically relevant to determining whether a director has a relationship to such company which is material to that director’s ability to be independent from management in connection with the duties of a compensation committee member, including: the source of compensation to the director, including any consulting, advisory or other compensatory fee paid by such company to the director,background, employment and whether the director is affiliated with the company or any of its subsidiaries or affiliates.

Our board of directorsaffiliations, our Board has determined that all memberseach of our current directors listed under “Information Regarding Director Nominees and Continuing Directors,” with the boardexception of directors, except Dr. Wilson, areAndrew Robbins, is an “independent director” as defined under the Nasdaq listing rules. Mr. Robbins is not an independent directors, including for purposes of the rules of Nasdaq and the SEC.director because he is our CEO. In making such independence determination,determinations, our board of directorsBoard considered the relationships that each such non-employee director has with usour Company and all other facts and circumstances that our board of directorsBoard deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director. In considering the independenceOur Board also determined that each of the directors listed above, our board ofcurrently serving on the Audit Committee and the Compensation Committee satisfy the additional independence criteria applicable to directors consideredon such committees under Nasdaq listing rules and the association of our directors withrules and regulations established by the holders of more than 5% of our common stock. There are no family relationships among any of our directors or executive officers. Dr. Wilson is not an independent director under these rules because he is an executive officer of the Company.SEC.

Board Committees

Our board of directorsBoard has established an audit committee, a compensation committee,separately designated Audit Committee, Compensation Committee, Nominating Committee and a nominating and corporate governance committee. Each of the audit committee, compensation committee, and nominating and corporate governance committee operates under a charter that satisfies the applicable standards of the SEC and Nasdaq. Each such committee reviews its respective charter at least annually. A current copy of the charter forScience Committee, each of which is comprised solely of independent directors with the audit committee, compensation committee,membership and nominatingresponsibilities described below. Members serve on these committees until their resignation or until otherwise determined by our Board. Other than the Science Committee, each of these committees is empowered to retain outside advisors as it deems appropriate, regularly reports its activities to the full Board and corporate governance committeehas a written charter which is posted on the corporate governance section of our website located at https://investors.unumrx.com/corporate-governanceinvestors.cogentbio.com/., under “Corporate Governance.”

Audit Committee

Jörn Aldag, Robert Perez. The primary responsibilities of our Audit Committee are to oversee the accounting and Liam Ratcliffe, M.D., Ph.D. currently serve on the audit committee, which is chaired by Jörn Aldag. At the timefinancial reporting processes of the Annual Meeting, since Mr. PerezCompany and Dr. Ratcliffe were not nominated forre-election by our nominatingits subsidiaries, including the audits of the Company’s financial statements, the integrity of the financial statements and corporate governancethe annual review of the performance, effectiveness and independence of the outside auditor. This includes reviewing the financial information provided to stockholders and others and the adequacy and effectiveness of the Company’s internal controls. The committee they will each be stepping down from the audit committee and Karen Ferrante, M.D. and Bruce Booth, DPhil will be appointedalso makes recommendations to the audit committee.Board as to whether financial statements should be included in the Company’s Annual Report on Form 10-K.

Our board of directors has determined that each member of the auditMr. Shegog qualifies as an “audit committee with the exception of Dr. Booth, is “independent” for audit committee purposesfinancial expert,” as that term is defined in the rules ofand regulations established by the SEC, and the applicable Nasdaq rules, and each has sufficient knowledge in financial and auditing matters to serve on the audit committee. Our board of directors has designated Jörn Aldag as an “audit committee financial expert,” as defined under the applicable rules of the SEC.

Dr. Booth will be appointed as anon-independent member of the audit committee pursuant to the exceptional and limited circumstances exemption under Nasdaq Rule 5605, Dr. Booth is not considered independent due to his affiliation with Atlas Venture Fund IX, L.P. Nasdaq Rule 5605(c)(2)(B) has an exception that allows onenon-independent member of the Audit Committee “if the board, under exceptional and limited circumstances, determines that membership on the committee is required by the best interests of the Company and its Shareholders.” The board of directors made that determination based on Dr. Booth’s deep understanding of the Company’s internal control systems and financial reporting. Dr. Booth may not serve longer than two years and may not chair the Audit Committee. The remaining twoall members of the Audit Committee are independent.“financially literate” under Nasdaq listing rules.

Compensation Committee. The primary responsibilities of our Compensation Committee are to periodically review and approve, or recommend to the Board for review and approval, where appropriate, the compensation and other benefits for our senior officers and directors. This includes reviewing and approving corporate goals and objectives relevant to the compensation of our senior officers, evaluating the performance of these officers in light of the goals and objectives, and setting the officers’ compensation based on those evaluations. The committee also administers and makes recommendations to the Board regarding equity incentive plans that are subject to the Board’s approval and approves the grant of equity awards under the plans. For compensation matters and equity grants to our CEO and Board members, the committee makes recommendations to the Board, and the Board is responsible for reviewing and approving all such matters.

The Compensation Committee may delegate its authority to one or more subcommittees. The committee may also delegate authority to review and approve the compensation of our employees to certain of our executive officers. Even where the committee does not delegate authority, our executive officers will typically make recommendations to the committee regarding compensation to be paid to our employees and the size of equity awards under our equity incentive plans, but will not be present during voting or deliberations on their own compensation. The committee has the authority to engage outside advisors, such as compensation consultants, to assist it in carrying out its responsibilities. The committee engaged Compensia, Inc. (“Compensia”) in 2022 to provide advice regarding the amount and form of executive and director compensation. The committee has determined that (1) the compensation consultant satisfies applicable independence criteria and (2) the compensation consultant’s work with the Company does not raise any conflicts of interest, in each case under applicable Nasdaq listing rules and the rules and regulations established by the SEC.

Nominating Committee. The primary responsibilities of our Nominating Committee are to engage in succession planning for the Board, develop and recommend to the Board criteria for identifying and evaluating qualified director candidates, and make recommendations to the Board regarding candidates for election or reelection to the Board at each annual stockholders’ meeting. In addition, the committee is responsible for overseeing our corporate governance practices and making recommendations to the Board concerning corporate governance matters. The committee is also responsible for making recommendations to the Board concerning the structure, composition and functioning of the Board and its committees.

Science Committee. The Science Committee assists our Board in ensuring that our research and development function is optimized to support our strategic goals, including to review and monitor the science, technology, process, procedures and infrastructure underlying our major discovery and development programs. The Science Committee makes recommendations to the Board regarding research and development strategies and opportunities.

Board Risk Oversight

We believe that risk management is an important part of establishing and executing on the Company’s business strategy. Our Board, as a whole and at the committee level, focuses its oversight on the most significant

risks facing the Company and on the Company’s processes to identify, prioritize, assess, manage and mitigate those risks. The committees oversee specific risks within their purview, as follows:

Our Board and its committees receive regular reports from members of the Company’s senior management on areas of material risk to the Company, including strategic, operational, financial, information technology and cybersecurity, and legal and regulatory risks. While our Board has an oversight role, management is principally tasked with direct responsibility for assessing and managing risks, including implementing processes and controls to mitigate their effects on the Company.

Oversight of Cybersecurity Risk

We collect, store and transmit sensitive information, including intellectual property, proprietary business information and personal information in connection with our business operations. The secure maintenance of this information is critical to our operations and business strategy. We have adopted oversight and management controls on our data security and have a process in place for incident detection, containment, response and remediation. We mitigate our cybersecurity risk in various ways, including by leveraging standard industry tools from a software and hardware perspective, maintaining a cybersecurity risk insurance policy and engaging with third-party security consultants to perform periodic data security risk assessments. We have established policies and procedures governing cybersecurity and data protection and conduct regular employee trainings on the current threat environment and phishing risk. In our industry, cyber-attacks are of ever-increasing levels of frequency and sophistication. However, to date, no cyber event has caused a material disruption to our business, or to our knowledge, involved a material security breach. We have retained VeraSafe, LLC (“VeraSafe”) to help review and monitor our practices and processes related to personal data and compliance with applicable data protection laws. VeraSafe acts as our Data Protection Officer and has served in this capacity since May 2021.

While everyone at the Company plays a part in maintaining our data security, the Audit Committee has been designated by our Board to oversee these specific risks. The Audit Committee receives reports from management and reviews business-related risk exposures and other risks relating to data privacy and cybersecurity, including a review of our policies and procedures, the integrity of our information technology systems and processes, the adequacy of our controls and contingency plans in the event of a cyber incident. The Board receives updates from management and the Audit Committee on cybersecurity risks on at least an annual basis.

Other Corporate Governance Practices and Policies

Director Attendance

During the fiscal year ended December 31, 2018,2022, the audit committeeBoard met fourseven times and acted by unanimous written consent three times. The report of the audit committee is included in this proxy statement under “Report of the Audit Committee.” The audit committee’s responsibilities include:

•

recommending based upon the audit committee’s review and discussions with management and our independent registered public accounting firm whether our audited financial statements shall be included in our Annual Report onForm 10-K;

All audit and non-audit services, other thande minimisnon-audit services, to be provided to us by our independent registered public accounting firm must be approved in advance by our audit committee.

Compensation Committee

Karen Ferrante, M.D., Robert Perez and Liam Ratcliffe, M.D., Ph.D. currently serve on the compensation committee, which is chaired by Liam Ratcliffe, M.D., Ph.D. At the time of the Annual Meeting, since Mr. Perez and Dr. Ratcliffe were not nominated forre-election by our nominating and corporate governance committee, they willDuring 2022, each be stepping down from the compensation committee and Bruce Booth, DPhil and Jörn Aldag will be appointed to the compensation committee, and Jörn Aldag will serve as the chair of the compensation committee. Our board of directors has determined that eachcurrent member of the compensation committee is “independent” as defined in the applicable Nasdaq rules. During the fiscal year ended December 31, 2018, the compensation committee met one time. The compensation committee’s responsibilities include:

Nominating and Corporate Governance Committee

Karen Ferrante, M.D., Jörn Aldag and Bruce Booth, DPhil. serve on the nominating and corporate governance committee, which is chaired by Bruce Booth, DPhil. Our board of directors has determined that each memberBoard attended at least 75% of the nominating and corporate governance committee is “independent” as defined in the applicable Nasdaq rules. During the fiscal year ended December 31, 2018, the

nominating and corporate governance committee met four times. The nominating and corporate governance committee’s responsibilities include:

The nominating and corporate governance committee considers candidates for Board of Director membership suggested by its members and the Chief Executive Officer. Additionally, in selecting nominees for directors, the nominating and corporate governance committee will review candidates recommended by stockholders in the same manner and using the same general criteria as candidates recruited by the committee and/or recommended by our Board of Directors. Any stockholder who wishes to recommend a candidate for consideration by the committee as a nominee for director should follow the procedures described later in this proxy statement under the heading “Stockholder Proposals.” The nominating and corporate governance committee will also consider whether to nominate any person proposed by a stockholder in accordance with the provisions of our bylaws relating to stockholder nominations as described later in this proxy statement under the heading “Stockholder Proposals.”

Identifying and Evaluating Director Nominees. Our Board of Directors is responsible for filling vacancies on our Board of Directors and for nominating candidates for election by our stockholders each year in the class of directors whose term expires at the relevant annual meeting. The Board of Directors delegates the selection and nomination process to the nominating and corporate governance committee, with the expectation that other members of the Board of Directors, and of management, will be requested to take part in the process as appropriate.

Generally, the nominating and corporate governance committee identifies candidates for director nominees in consultation with management, through the use of search firms or other advisors, through the recommendations submitted by stockholders or through such other methods as the nominating and corporate governance committee deems to be helpful to identify candidates. Once candidates have been identified, the nominating and corporate governance committee confirms that the candidates meet all of the minimum qualifications for director nominees established by the nominating and corporate governance committee. The nominating and corporate governance committee may gather information about the candidates through interviews, detailed questionnaires, comprehensive background checks or any other means that the nominating and corporate governance committee deems to be appropriate in the evaluation process. The nominating and corporate governance committee then meets as a group to discuss and evaluate the qualities and skills of each candidate, both on an individual basis and taking into account the overall composition and needs of our Board of Directors. Based on the results of the evaluation process, the nominating and corporate governance committee recommends candidates for the Board of Directors’ approval to fill a vacancy or as director nominees for election to the Board of Directors by our stockholders each year in the class of directors whose term expires at the relevant annual meeting.

Board and Committee Meetings Attendance

The full board of directors met five times during 2018. During 2018, each member of the board of directors attended in person or participated in 75% or more of the aggregate of (i) the total number of meetings of the board of directors (heldBoard and the committees on which he or she served during the period forin which such person has been a director) and (ii)he or she was on the total number of meetings held by all committees of the board of directors on which such person served (during the periods that such person served).

Director Attendance at Annual Meeting of Stockholders

Board or committee. Directors are responsible for attendingencouraged to attend the annual meeting of stockholders. All of our directors then serving on the Board attended the 2022 Annual Meeting of Stockholders.

Stockholder Communications

Stockholders and other interested parties may communicate with our Board or a particular director by sending a letter addressed to the Board or a particular director to our Corporate Secretary at the address set forth on the first page of this Proxy Statement. These communications will be compiled and reviewed by our Corporate Secretary, who will determine whether the communication is appropriate for presentation to the Board or the particular director. The purpose of this screening is to allow the Board to avoid having to consider irrelevant or inappropriate communications (such as advertisements, solicitations and hostile communications).

To enable the Company to speak with a single voice, as a general matter, senior management serves as the primary spokesperson for the Company and is responsible for communicating with various constituencies, including stockholders, on behalf of the Company. Directors may participate in discussions with stockholders and other constituencies on issues where Board-level involvement is appropriate. In addition, the Board is kept informed by senior management of the Company’s stockholder engagement efforts.

Code of Business Conduct and Ethics

Our Board has adopted a written code of business conduct and ethics that applies to our directors, officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. A current copy of the code is available on our website located at https://investors.cogentbio.com/, under “Corporate Governance.” We intend to disclose any amendments to the code, or any waivers of its requirements, on our website to the extent practicable. We did not hold an annual meeting of stockholders in 2018.required by applicable rules.

Anti-Hedging Policy on Trading, Pledging and Hedging of Company Stock

Certain transactions in our securities (such as purchases and sales of publicly traded put and call options, and short sales) create a heightened compliance risk or could create the appearance of misalignment between management and stockholders. In addition, securities held in a margin account or pledged as collateral may be sold without consent if the owner fails to meet a margin call or defaults on the loan, thus creating the risk that a sale may occur at a time when an officer or director is aware of material, non-public information or otherwise is not permitted to trade in Company securities. Our insider trading policy expressly prohibits short sales and derivative transactions of our stock by our executive officers, directors, employees and certain designated consultants and contractors, including short sales of our securities.contractors. Our insider trading policy also expressly prohibits, without the advance approval of our audit committee, purchases or sales of puts, calls or other derivative securities of the companyCompany or any derivative securities or any hedging transactions that provide the economic equivalent of ownership.

Code of Business Conduct and Ethics

We have adopted a written code of business conduct and ethics that applies to our directors, officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. A current copy of the code is posted on the corporate governance section of our website, which is located athttps://investors.unumrx.com/corporate-governance. If we make any substantive amendments to, or grant any waivers from, the code of business conduct and ethics for any officer or director, we will disclose the nature of such amendment or waiver on our website or in a current report on Form 8-K.

Board Leadership Structure and Board’s Role in Risk Oversight

Currently, the role of chairman of the board is separated from the role of chief executive officer. We believe that separating these positions allows our chief executive officer to focus on ourday-to-day business, while allowing the chairman of the board to lead the board of directors in its fundamental role of providing advice to, and independent oversight, of management. Our board of directors recognizes the time, effort, and energy that the chief executive officer is required to devote to his position in the current business environment, as well as the commitment required to serve as our chairman, particularly as the board of directors’ oversight responsibilities continue to grow. While our bylaws and our corporate governance guidelines do not require that our chairman and chief executive officer positions be separate, our board of directors believes that having separate positions is the appropriate leadership structure for us at this time and demonstrates our commitment to good corporate governance.

Risk is inherent to every business, and how well a business manages risk can ultimately determine its success. We face a number of risks, including risks relating to our financial condition, development and commercialization activities, operations, strategic direction, and intellectual property. Management is responsible for theday-to-day management of risks we face, while our board of directors, as a whole and through its committees, has responsibility for the oversight of risk management. In its risk oversight role, our board of directors has the responsibility to satisfy itself that the risk management processes designed and implemented by management are adequate and functioning as designed.

The role of the board of directors in overseeing the management of our risks is conducted primarily through committees of the board of directors, as disclosed in the descriptions of each of the committees above and in the charters of each of the committees. The full board of directors (or the appropriate board committee in the case of risks that are under the purview of a particular committee) discusses with management our major risk exposures, their potential impact on us, and the steps we take to manage them. When a board committee is responsible for evaluating and overseeing the management of a particular risk or risks, the chairman of the relevant committee reports on the discussion to the full board of directors during the committee reports portion of the next board meeting. This enables the board of directors and its committees to coordinate the risk oversight role, particularly with respect to risk interrelationships.

Communication with the Directors of Unum

Any interested party with concerns about our company may report such concerns to the board of directors or the chairman of our board of directors and nominating and corporate governance committee, by submitting a written communication to the attention of such director at the following address:

c/o Unum Therapeutics Inc.

200 Cambridge Park Drive, Suite 3100

Cambridge, Massachusetts 02140

United States

You may submit your concern anonymously or confidentially by postal mail. You may also indicate whether you are a stockholder, customer, supplier, or other interested party.

A copy of any such written communication may also be forwarded to Unum’s legal counsel and a copy of such communication may be retained for a reasonable period of time. The director may discuss the matter with Unum’s legal counsel, with independent

advisors, with non-management directors, or with Unum’s management, or may take other action or no action as the director determines in good faith, using reasonable judgment, and applying his or her own discretion. Communications may be forwarded to other directors if they relate to important substantive matters and include suggestions or comments that may be important for other directors to know. In general, communications relating to corporate governance and long-term corporate strategy are more likely to be forwarded than communications relating to ordinary business affairs, personal grievances, and matters as to which we tend to receive repetitive or duplicative communications.

The audit committee oversees the procedures for the receipt, retention, and treatment of complaints received by Unum regarding accounting, internal accounting controls, or audit matters, and the confidential, anonymous submission by employees of concerns regarding questionable accounting, internal accounting controls or auditing matters. Unum has also established a toll-free telephone number for the reporting of such activity, which is (888)639-7294 and a website https://www.whistleblowerservices.com/unum.

Director Compensation

The table below shows all compensation paid to or earned byOutside Director Compensation Policy

We adopted a policy for compensating our non-employee directors during the fiscal year ended December 31, 2018. Dr. Wilson, our Chief Executive Officer and a member of our board of directors, did not receive any compensation for his service as a member of our board of directors during 2018. Dr. Wilson’s compensation for service as an employee for fiscal year 2018 is presented below in the “Summary Compensation Table” below.

Under our director compensation policy, which became effective upon the completion of our initial public offering, we pay our non-employee directors a cash retainer for service on the board of directorsBoard and for service on each committee on which the director is a member. The chairman of each committee receives a higher retainer for such service. These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment is prorated for any portion of such quarter that the director is not serving on our boardBoard. The Compensation Committee periodically reviews compensation paid to our non-employee directors, considering input from the Compensation Committee’s independent compensation consultant, and makes recommendations for adjustments, as appropriate, to the full

Board. The Board recently approved changes to the outside director compensation program, as reflected below, in order to maintain compensation levels for our non-employee directors that are at the 50^th percentile of directors.our peer companies. The fees paidpayable to non-employee directors for service on the board of directorsBoard and for service on each committee of the board of directorsBoard on which the director was or is a member in 2022 and 2023 are as follows:

		2022 Annual Retainer				2023 Annual Retainer
Board of Directors:
All non-employee directors		$	40,000			$	40,000
Additional retainer for Non-Executive Chairman of the Board		$	30,000			$	30,000
Audit Committee:
Chairman		$	15,000			$	15,000
Non-Chairman members		$	7,500			$	7,500
Compensation Committee:
Chairman		$	11,000			$	13,500
Non-Chairman members		$	5,500			$	6,750
Nominating Committee:
Chairman		$	8,000			$	10,000
Non-Chairman members		$	4,000			$	5,000
Science Committee:
Chairman			—			$	13,500
Non-Chairman members			—			$	6,750

We also reimburse our non-employee directors for reasonable travel andout-of-pocket expenses incurred in connection with attending our board of directorany in-person Board and committee meetings.

Pursuant to our director compensation policy, directors are given the opportunity to elect to receive all or a portion of their retainer and committee fees in the form of an equity award ofof: (a) unrestricted shares having a grant date fair value equal to the amount (or portion thereof) of such retainer and committee fees or (b) fully vested stock options to purchase common stock based on the Black-Scholes option-pricing model as of the date of grant. Any such election must be mademade: (i) for any continuingnon-employee director, before the start of the calendar year with respect to any cash compensation for such calendar year and (ii) for any newnon-employee director, within 30 days of her or his election to the board of directors.Board. Any such stock options are fully vested upon grant and expire ten years from the date of grant.

In addition, our director compensation policy provides that each newnon-employee director elected to our board of directorsBoard receives an initial,one-time stock option grant to purchase 28,66161,400 (increased to 73,400 beginning in 2023) shares of our common stock (the “Initial Award”), which vests in equal monthly installments over three years, subject to continued service as a member of the board of directors.Board. In addition, each continuingnon-employee member of the boarddirector, other than a director receiving an Initial Award, receives, at the time of the Company’s annual meeting, an annual equity grant of options to purchase 14,33130,700 (increased to 36,700 beginning in 2023) shares of our common stock, which vests in full upon the earlier of the first anniversary of the date of grant or the date of the Company’s next annual meeting of the Company’s stockholders, subject to continued service as a member of the board of directorsBoard through such date.

This program is intended to provide a total compensation package that enables us to attract and retain qualified and experienced individuals to serve as directors and to align our directors’ interests with those of our stockholders.

Fiscal Year 2022 Director Compensation Table

The table below shows all compensation paid to or earned in 2022 by our non-employee directors. Executives who serve as directors do not receive any compensation for service as a director. The compensation received by Mr. Robbins for his service to us during 2022 as our Chief Executive Officer is presented in the 2022 Summary Compensation Table in “Executive Compensation” below.

Compensation Committee Interlocks and Insider Participation

None of the members of our Compensation Committee has at any time during the prior three years been one of our officers or employees. None of our executive officers currently serves, or in the past fiscal year has served, as a member of the board or compensation committee of any entity that has one or more executive officers serving on our Board or Compensation Committee.

ENVIRONMENTAL, SOCIAL AND GOVERNANCE

Environmental, social and governance (“ESG”) matters are a priority to us. Our Nominating Committee oversees this commitment, our ESG initiatives and progress towards related goals and targets. Our current ESG focus areas are as follows:

Our Patients

Our mission is to deliver the next best-in-class therapy for patients with genetically defined diseases – to move beyond incremental improvements and solely treating symptoms, to address the real causes of disease. We are methodical, rational and intentional in our approach to identify pragmatic solutions to complex health challenges with the goal of restoring health and allowing patients to live better, longer lives. In pursuing our mission, patient safety is of the utmost importance. We follow the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (“ICH”) guidelines on Good Clinical Practice (“GCP”) and the ethical principles that have their origin in the Declaration of Helsinki in designing and conducting our clinical trials. Our protocols are approved by national and local bodies and all of our participants undergo thorough and informed consent processes. Furthermore, we provide travel reimbursement to help reduce barriers so that patients with diverse backgrounds are able to participate in our clinical trials.

Our Diverse Workforce

We believe that our future success largely depends upon our continued ability to attract and retain a diverse group of highly skilled employees. As of March 31, 2023, women comprise 57% of our total employee population and 50% of our employee leaders at the level of Vice President or above. We do not ask our employees to self-identify by race or ethnicity and therefore do not maintain metrics on this information. We provide our employees with competitive salaries and bonuses, opportunities for equity ownership, development programs that enable continued learning and growth and a robust employment package that promotes well-being across all aspects of their lives, including health care, retirement planning and paid time off.

Our Environment

We currently lease our office facilities and lab spaces. Nonetheless, we periodically review our environmental impact and consider opportunities to optimize our operations. We are committed to the responsible management of hazardous materials and lab waste and have various initiatives in place to foster a more sustainable and safer environment. Our corporate headquarters are located at 275 Wyman St. in Waltham, Massachusetts, which has a LEED Platinum certification. Our research team and laboratory facilities are located at 4840 Pearl East Circle in Boulder, Colorado, which is Boulder’s first LEED-EB (Existing Building) certified building. Our Boulder research facility uses a system that recovers energy from the lab exhaust to precondition the air supplied to the labs, thereby reducing the energy needed to heat and cool them. At both of our facilities, we have implemented robust composting and recycling programs, including recycling of lab specific plastic waste streams in Boulder that are not accepted by the municipal program, and we aim to reduce our water use and consumption of single-use plastics. We also provide certain commuter benefits, including bike-to-work and public transportation subsidies, and have a flexible work-from-home program for certain roles to help reduce carbon emissions.

Our Community

We are committed to the communities in which we operate. The Company and our employees participate in multiple charitable endeavors each year. We also believe it is important to invest in the next generation of scientists, and we have engaged with local schools and students in the Boston and Boulder areas to facilitate interest in the science and technology fields.

EXECUTIVE OFFICERS

Biographical and other information regarding our executive officers is set forth below. There are no family relationships among any of our directors or executive officers.

John Green. Mr. Green has served as our Chief Financial Officer, principal accounting officer and principal financial officer since July 2020. Prior to his promotion, Mr. Green was our Vice President of Finance and Controller from April 2018 to June 2020. Mr. Green brings nearly 20 years of strategic finance and accounting experience to his position, nearly half of which has been in the biotechnology industry for both public and private companies. Prior to joining Cogent, Mr. Green served as Principal Accounting Officer at Merrimack Pharmaceuticals, Inc. (Nasdaq: MACK), a biopharmaceutical company, from March 2017 to June 2018. From November 2015 to March 2017, he served as the Controller at Fractyl Laboratories, Inc., a medical technology company. From June 2014 to November 2015, Mr. Green served as Director of Accounting at Dicerna Pharmaceuticals, Inc. (Nasdaq: DRNA), a biopharmaceutical company. Mr. Green is a Chartered Professional Accountant and holds a B.S. in Chemistry and Biology from Acadia University.

Evan Kearns. Mr. Kearns has served as our Chief Legal Officer and Corporate Secretary since May 2021 and is responsible for the Company’s legal and compliance functions. Mr. Kearns has over 16 years of experience in and serving the biotechnology industry. Prior to joining the Company, Mr. Kearns served as Vice President, General Counsel, Corporate Secretary and Chief Compliance Officer at Agenus Inc. (Nasdaq: AGEN), a biotechnology company, from July 2018 to April 2021, where he was responsible for corporate and securities law matters, as well as M&A, financing and licensing transactions and corporate governance matters. From December 2017 to July 2018, he served as Vice President, Associate General Counsel at Agenus in a similar capacity. Before joining Agenus, he served as a life sciences corporate associate in the Boston office of Goodwin Proctor LLP, an international law firm. Mr. Kearns received his J.D. from the University of Toledo College of Law and his B.A. in Economics from Colby College.

John Robinson, Ph.D. Dr. Robinson has served as our Chief Scientific Officer since April 2021. He has over 20 years of small molecule drug discovery experience. Prior to joining the Company, Dr. Robinson served as Vice President of Medicinal Chemistry at Pfizer Boulder Research and Development, a drug discovery and development center, from July 2019 to March 2021. From December 2002 to July 2019, he served in a variety of scientific and leadership positions at Array BioPharma Inc., a biopharmaceutical company, including most recently, as Executive Director and Head of Chemistry. Dr. Robinson received his B.S. in Biochemistry from Indiana University of Pennsylvania and his Ph.D. in Synthetic Organic Chemistry from the University of Delaware.

Jessica Sachs, M.D. Dr. Sachs has served as our Chief Medical Officer since June 2019. Prior to assuming this role, she served as our Vice President of Clinical Sciences from April 2017 to June 2019, and she was responsible for the clinical development strategy and medical and translational oversight of the Cogent portfolio. Dr. Sachs has over 20 years of experience in oncology and pediatrics. From 2012 to April 2017, Dr. Sachs served as Senior Medical Director of Clinical Research at Takeda Pharmaceutical Company Limited (NYSE: TAK), a

global biopharmaceutical company, where she led multiple clinical programs in oncology and transplantation. From 2010 to 2012, Dr. Sachs was Associate Director at Genzyme Corporation, a biotechnology company, where she was responsible for post-marketing safety surveillance and risk management activities for a variety of oncology products. Dr. Sachs has been a faculty member of the Harvard Medical School since 2007 and is an Assistant in Pediatrics in the Division of Pediatric Hematology/Oncology at the Massachusetts General Hospital. She completed her fellowship in pediatric hematology and oncology at the Dana Farber Cancer Institute and Children’s Hospital Boston. She received her M.D. from Washington University in St. Louis and her B.S. from Duke University.

EXECUTIVE COMPENSATION

Our named executive officers (“NEOs”) for 2022, which consist of our principal executive officer and the year ended December 31, 2018next two most highly compensated executive officers, are:

2022 Summary Compensation Table

The following table presentssummarizes the compensation awarded to, earned by or paid to each of our named executive officersNEOs for the years indicated.2022 and 2021.

Narrative to Summary Compensation Table

Our board of directorsBoard and compensation committeeCompensation Committee review compensation practices and philosophy annually for all employees, including our executives. In setting executive base salaries and bonuses and granting equity incentive awards, they consider compensation for comparable positions in the market, the historical compensation levels of our executives, individual performance as compared to our expectations

and objectives, our desire to motivate our employees to achieve short-and long-term results that are in the best interests of our stockholders and our desire to incentivize a long-term commitment to our company.Company. We target a general competitive position, based on independent third-party benchmark analytics to inform the mix of compensation of base salary, bonus and long-term incentives.

Our Compensation Committee is responsible for approving all executive compensation committee has historically determinedmatters other than for our executives’ compensation.CEO, which must be recommended to the Board for approval. Our compensation committeeCompensation Committee typically reviews and discusses management’s proposed compensation with the chief executive officerCEO for all executives other than the chief executive officer.CEO. Based on those discussions and its discretion, taking into account the factors noted above, the compensation committeeCompensation Committee then determines the compensation for each executive officer.officer other than the CEO. In 2018,2022, the compensation committeeCompensation Committee retained the services of Radford, an AON company,Compensia as its external compensation consultant and the board of directorsBoard and the compensation committeeCompensation Committee considered Radford’sCompensia’s input on certain compensation matters as they deemed appropriate. Our compensation committee has assessed the independence of Radford consistent with Nasdaq listing standards and has concluded that the engagement of Radford does not raise any conflict of interest.

Annual base salaryBase Salary

Each named executive officer’s base salary is a fixed component of annual compensation for performing specific duties and functions, and has been established by our board of directorsBoard taking into account each individual’s role, responsibilities, skills and experience. Base salaries for our named executive officers are reviewed annually by our compensation committee,Compensation Committee, typically in connection with our annual performance review process, and adjusted from time to time, based on the recommendation of the compensation committee,Compensation Committee, to realign salaries with market levels after taking into account individual responsibilities, performance and experience.experiences.

Cash bonusBonus

From time to time, our board of directorsBoard or compensation committeeCompensation Committee may approve annual bonuses for our named executive officers based on individual performance, companyCompany performance or as otherwise determined appropriate. Cash bonuses for the 2022 performance year were funded at 92% of target based on achievement of corporate goals in 2022.

Long-term equity incentivesLong-Term Equity Incentives

Our equity grant program is intended to align the interests of our named executive officers with those of our stockholders and to motivate them to make important contributions to our performance. During the year ended December 31, 2018,2022, we made grants of stock options to each of our named executive officers. The grant date fair values of such awards are set forth in the “Summary“2022 Summary Compensation Table” above and the number of shares underlying such awards and the vesting terms of such awards are set forth in the “Outstanding Equity Awards at 20182022 Fiscal Year End Table” below.

Outstanding Equity Awards at 20182022 Fiscal Year End Table

The following table presentssets forth information regarding all outstanding stock options held byequity awards at the end of 2022 for each of our named executive officers on December 31, 2018.NEOs.

(1)Dr. Wilson’s stock option granted on March 28, 2018 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, March 16, 2018, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Dr. Wilson’s continuous service with us.

(2)Dr. Vasconcelles’ stock option granted on November 4, 2015 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, October 20, 2015, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Dr. Vasconcelles’ continuous service with us.

(3) Dr. Vasconcelles’ stock option granted on October 27, 2017 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, October 27, 2017, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Dr. Vasconcelles’ continuous service with us.

(4) Dr. Vasconcelles’ stock option granted on March 28, 2018 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, March 16, 2018, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Dr. Vasconcelles’ continuous service with us.

(5) Ms. Stamoulis’ stock option granted on January 29, 2015 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, January 9, 2015, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Ms. Stamoulis’ continuous service with us

(6) Ms. Stamoulis’ stock option granted on April 30, 2015 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, April 30, 2015, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Ms. Stamoulis’ continuous service with us.

(7) Ms. Stamoulis’ stock option granted on October 27, 2017 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, October 27, 2017, and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Ms. Stamoulis’ continuous service with us.

(8) Ms. Stamoulis’ stock option granted on March 28, 2018 vests over four years, with 25% of the shares vesting on the first anniversary of the vesting commencement date, March 16, 2018 and the remaining shares vesting in 36 equal monthly installments thereafter, subject to Ms. Stamoulis’ continuous service with us.

Employment arrangementsArrangements with our named executive officersNamed Executive Officers

In connection with our IPO, weWe have entered into employment agreements with each of our named executive officers. Each of our named executive officers is employed at will.

Charles Wilson, Ph.D.Andrew Robbins.

For the year ended December 31, 2018, priorMr. Robbins’s employment agreement provides for “at will” employment. Pursuant to the completionterms of our IPO, Dr. Wilson’shis employment agreement, Mr. Robbins is entitled to an annual base salary, which was $360,000 and hisset at $624,855 for 2022. Mr. Robbins is also eligible for annual cash incentive bonus target was equal to 30%compensation targeted at 60% of his base salary. UponMr. Robbins is eligible to participate in the effectivenessemployee benefit plans generally available to full-time employees, subject to the terms of our IPO, Dr. Wilson’s base salary was increasedthose plans. Pursuant to $528,000 and his annual cash incentive bonus target was increased to 50%the terms of his base salary.

Dr. Wilson’s employment agreement, provides that, in the event that Dr. Wilson’sif Mr. Robbins’s employment is terminated by usthe Company without “cause” or Dr. Wilson resigns for “good reason”cause (as each is defined in thehis employment agreement) or by Mr. Robbins for good reason (as defined in his employment agreement), Mr. Robbins will receive any base salary through the date of termination, unpaid expense reimbursements, unused vacation accrued through the date of termination and any vested benefits under any employee benefit plan through the date of termination. Additionally, subject to theMr. Robbins’s execution and effectiveness of a separation agreement, including a general release of potential claims in our favor, heagainst the Company, Mr. Robbins will be entitled to receivereceive: (i) a lump sum in cash in an amount equal to 12 months of base salary, payable in lump sum within 60 days after the date of termination, (ii) if Dr. Wilson is participating in our group health plan immediately prior to his termination and elects COBRA health continuation, a monthly cash payment until the earlier offor 12 months following terminationfor medical and dental benefits or the end of Dr. Wilson’sMr. Robbins’s COBRA health continuation period, whichever ends earlier, (iii) a lump sum in cash in an amount equal to 100% of Mr. Robbins’s target bonus for the amount that we would have made to provide health insurance to Dr. Wilson had he remained employed with us,then-current year and (iii)(iv) acceleration of equity awardsvesting on any time-based options in an amount thatwhich Mr. Robbins would have vested if he had remained employed for an additional 12 months. However, in the event that Mr. Robbins’s employment is terminated by the Company without cause, or Mr. Robbins terminates his employment with the Company for good reason, in either case for a period of 90 days prior to or 12 months following the dateoccurrence of a change in control (as defined in his termination. The employment agreement also provides that,agreement), in lieu of the severance payments and benefits described above,in the preceding sentence and subject to Mr. Robbins’s execution of a release of potential claims against the Company, Mr. Robbins will be entitled to receive: (i) a lump sum in cash in an amount equal to 18 months of base salary, (ii) a lump sum in cash in an amount equal to 150% of Mr. Robbins’s target bonus for the then-current year, (iii) a monthly cash payment for 18 months for medical and dental benefits or Mr. Robbins’s COBRA health continuation period, whichever ends earlier and (iv) acceleration of vesting on any options.

Jessica Sachs, M.D. Dr. Sachs’s employment agreement provides for “at will” employment. Pursuant to the terms of her employment agreement, Dr. Sachs is entitled to an annual base salary, which was set at $483,000 for 2022. Dr. Sachs is also eligible for annual incentive compensation targeted at 40% of her base salary. Dr. Sachs is eligible to participate in the employee benefit plans generally available to full-time employees, subject to the terms of those plans. Pursuant to the terms of her employment agreement, if Dr. Sachs’s employment is terminated by us without cause (as defined in her employment agreement) or by Dr. Sachs for good reason (as defined in her employment agreement), Dr. Sachs will receive any base salary through the date of termination, unpaid expense reimbursements, unused vacation accrued through the date of termination and any vested benefits under any employee benefit plan through the date of termination. Additionally, subject to Dr. Sachs’s execution of a release of potential claims against us, Dr. Sachs will be entitled to receive: (i) a lump sum in cash in an amount equal to 12 months of base salary, (ii) a monthly cash payment for nine months for medical and dental benefits or Dr. Sachs’s COBRA health continuation period, whichever ends earlier, (iii) a lump sum in cash in an amount equal to Dr. Sachs’ target bonus for the then-current year pro-rated based on the portion of the year that Dr. Sachs was employed, and (iv) acceleration of vesting on any time-based equity awards in which Dr. Sachs would have vested if she had remained employed for an additional nine months. However, in the event that Dr. Wilson’sSachs’s employment is terminated by us without cause, or Dr. Wilson resignsSachs terminates her employment with us for good reason, in either case within 12 months following the occurrence of a “changechange in control”control (as defined in theher employment agreement), in lieu of the severance payments and benefits described in the preceding sentence and subject to theDr. Sachs’s execution and effectiveness of a separation agreement, including a general release of potential claims in our favor, heagainst us, Dr. Sachs will be entitled to receivereceive: (i) a lump sum in cash paymentin an amount equal to 1812 months of his then-current base salary, (or his base salary(ii) a lump sum in effect immediately priorcash in an amount equal to the change in control, if higher) plus 150 percent100% of hisDr. Sachs’s target bonus (ii) if Dr. Wilson is participating in our group health plan immediately prior to his termination,for the then-current year, (iii) a monthly cash payment until the earlier of 18for 12 months following terminationfor medical and dental benefits or the end of Dr. Wilson’sSachs’s COBRA health continuation period, in an amount equal to

the amount that we would have made to provide health insurance to him had he remained employed with uswhichever ends earlier and (iii) full(iv) acceleration of vesting on all equity awards held by awards.

John Robinson, Ph.D. Dr. Wilson.

Robinson’s employment agreement provides for “at will” employment. Pursuant to the terms of his employment agreement, Dr. WilsonRobinson is entitled to an annual base salary, which was set at $454,750 for 2022. Dr. Robinson is also eligible for annual incentive compensation targeted at 40% of his base salary. Dr. Robinson is eligible to participate in the employee benefit plans generally available to ourfull-time employees, subject to the terms of those plans.

Michael Vasconcelles, M.D.

For the year ended December 31, 2018, prior Pursuant to the completion of our IPO, Dr. Vasconcelles’ base salary was $386,250 and his annual cash incentive bonus target was equal to 30%terms of his base salary. Upon the effectiveness of our IPO, Dr. Vasconcelles’ base salary was increased to $425,000 and his annual cash incentive bonus target was increased to 35% of his base salary.

Dr. Vasconcelles’ employment agreement, provides that, in the event thatif Dr. Vasconcelles’Robinson’s employment is terminated by us without “cause” or Dr. Vasconcelles resigns for “good reason”cause (as each is defined in thehis employment agreement) or by Dr. Robinson for good reason (as defined in his employment agreement), Dr. Robinson will receive any base salary through the date of termination, unpaid expense reimbursements, unused vacation accrued through the date of termination and any vested benefits under any employee benefit plan through the date of termination. Additionally, subject to theDr. Robinson’s execution and effectiveness of a separation agreement, including a general release of potential claims in our favor, heagainst us, Dr. Robinson will be entitled to receivereceive: (i) an amount equal to nine months of base salary, payable ina lump sum within 60 days after the date of termination, (ii) if Dr. Vasconcelles is participating in our group health plan immediately prior to his termination and elects COBRA health continuation, a monthly cash payment until the earlier of nine months following termination or the end of Dr. Vasconcelles’ COBRA health continuation period in an amount equal to the12 months of base salary, (ii) a monthly cash payment for nine months for medical and dental benefits or Dr. Robinson’s COBRA health continuation period, whichever ends earlier, (iii) a lump sum in cash in an amount that we would have made to provide health insuranceequal to Dr. Vasconcelles had he remainedRobinson’s target bonus for the then-current year pro-rated based on the portion of the year that Dr. Robinson was employed with us, and (iii)(iv) acceleration of vesting on any time-based equity awards in an amount thatwhich Dr. Robinson would have vested if he had remained employed for an additional nine months following the date of his termination. The employment agreement also provides that, in lieu of the payments and benefits described above,months. However, in the event that Dr. Vasconcelles’Robinson’s employment is terminated by us without cause, or Dr. Vasconcelles resignsRobinson terminates his employment with us for good reason, in either case within 12 months following the occurrence of a “changechange in control”control (as defined in thehis employment agreement), in lieu of the severance payments and benefits described in the preceding sentence and subject to theDr. Robinson’s execution and effectiveness of a separation agreement, including a general release of potential claims in our favor, heagainst us, Dr. Robinson will be entitled to receivereceive: (i) a lump sum in cash paymentin an amount equal to 12 months of his then-current base salary, (or his base salary(ii) a lump sum in effect immediately prior to the change in control, if higher) plus 100 percent of his target bonus, (ii) if Dr. Vasconcelles is participating in our group health plan immediately prior to his termination, a monthly cash payment until the earlier of 12 months following termination or the end of Dr. Vasconcelles’ COBRA health continuation period in an amount equal to 100% of Dr. Robinson’s target bonus for the amount that we would have made to provide health insurance to him had he remained employed with us andthen-current year, (iii) full acceleration of all equity awards held by Dr. Vasconcelles.

Dr. Vasconcelles is also eligible to participate in the employee benefit plans available to our employees, subject to the terms of those plans.

Christiana Stamoulis

Effective January 31, 2019, Ms. Stamoulis resigned from her position of President and Chief Financial Officer of Unum. For the year ended December 31, 2018, prior to the completion of our IPO, her base salary was $360,000 and her annual cash incentive bonus target was 35% of her base salary. Upon the effectiveness of our IPO, Ms. Stamoulis’ annual base salary was increased to $425,000 and her annual cash incentive bonus target remained at 35% of her base salary.

Ms. Stamoulis’ employment agreement provided that, in the event that Ms. Stamoulis’ employment was terminated by us without “cause” or Ms. Stamoulis resigned for “good reason” (as each is defined in the employment agreement), subject to the execution and effectiveness of a separation agreement, including a general release of claims in our favor, she would have been entitled to receive (i) an amount equal to nine months of base salary, payable in lump sum within 60 days after the date of termination, (ii) if Ms. Stamoulis is participating in our group health plan immediately prior to her termination and elects COBRA health continuation, a monthly cash payment until the earlier of ninefor 12 months following terminationfor medical and dental benefits or the end of Ms. Stamoulis’Dr. Robinson’s COBRA health continuation period, in an amount equal to the amount that we would have made to provide health insurance to Ms. Stamoulis had she remained employed with us,whichever ends earlier and (iii)(iv) acceleration of equity awards in an amount that would have vested if she had remained employed for an additional nine months following the date of her termination. The employment agreement also provided that, in lieu of the payments and benefits described above, in the event that Ms. Stamoulis’ employment was terminated by us without cause or Ms. Stamoulis resigns for good reason, in either case within 12 months following a “change in control” (as defined in the employment agreement), subject to the execution and effectiveness of a separation agreement, including a general release of claims in our favor, she would have been entitled to receive (i) a lump sum cash payment equal to 12 months of her then-current base salary (or her base salary in effect immediately prior to the change in control, if higher) plus 100 percent of her target bonus, (ii) if Ms. Stamoulis is participating in our group health plan immediately prior to her termination, a monthly cash payment until the earlier of 12 months following termination or the end of Ms. Stamoulis’ COBRA health continuation period in an amount equal to the amount that we would have made to provide health insurance to her had she remained employed with us and (iii) full acceleration ofvesting on all equity awards held by Ms. Stamoulis.awards.

Ms. Stamoulis was also eligible to participate in the employee benefit plans available to our employees, subject to the terms of those plans.

Additional Narrative Disclosure

401(k) Plan

401(k) Plan.We maintain the Unum TherapeuticsCogent Biosciences, Inc. 401(k) Plan, atax-qualified retirement plan for our employees. The 401(k) planPlan is intended to qualify under Section 401(k) of the Internal Revenue Service Code of 1986, as amended, so that contributions to the 401(k) planPlan by employees or by us, and the investment earnings thereon, are not taxable to the employees until withdrawn from the 401(k) plan,Plan, and so that contributions by us, if any, will be deductible by us when made. Under the 401(k) plan,Plan, employees may elect to reduce their current compensation by up to the statutorily prescribed annual limit and to have the amount of such reduction contributed to the 401(k) plan.Plan. We currently match 100% of an employee’s contributions to the 401(k) Plan up to 4% of an employee’s compensation.

Health and Welfare Benefits.

All of our full-time employees, including our executive officers, are eligible to participate in certain medical, disability and life insurance benefit programs offered by us. We pay the premiums for term life insurance and long-term disability for all of our employees, including our executive officers. We also provide all employees, including executive officers, with a flexible spending account plan, an employee stock purchase plan and paid time off benefits, including vacation, sick time and holidays. Although we have adopted an employee stock purchase plan, the Company has not yet made any offerings under such plan. We do not sponsor any qualified or non-qualified defined benefit plans for any of our employees or executives.

Other Retirement Benefits

We do not maintain any defined benefit pension plans. In 2021, we adopted a nonqualified deferred compensation plan pursuant to which eligible participants, including our executive officers, may elect to defer a portion of their eligible compensation. None of the NEOs participated in the plan during 2022.

CERTAIN INFORMATION ABOUT OUR COMMON STOCK

Security Ownership of Certain Beneficial Owners and Management

The following table presents information regarding beneficial ownership of our common stock as of March 31, 2023 by:

Beneficial ownership is determined in accordance with the rules of the SEC. Under such rules, beneficial ownership includes any shares of common stock over which the individual or entity has sole or shared voting power or investment power as well as any shares of common stock that the individual or entity has the right to acquire within 60 days after March 31, 2023. To our knowledge and subject to applicable community property rules, and except as otherwise indicated below, the persons and entities named in the table have sole voting and sole investment power with respect to all shares beneficially owned.

The percentage ownership information shown in the column titled “Percentage of Shares Beneficially Owned” in the table below is based on 70,946,790 shares of our common stock outstanding as of March 31, 2023 (plus, as to any particular beneficial owner, any shares as to which such person has the right to acquire beneficial ownership within 60 days thereafter). Unless otherwise indicated, the address of each beneficial owner listed in this table is the Company’s address set forth on the first page of this Proxy Statement.

Securities Authorized for Issuance Under Equity Compensation Plan InformationPlans

The following table provides information as of December 31, 20182022 with respect to the shares of our common stock that may be issued under our existing equity compensation plans.