Prime Medicine (PRME) PRE 14APreliminary proxy

Check the appropriate box:

The Annual Meeting will be held for the following purposes:

Our Board of Directors has established the close of business on April 19, 2024 as the “record date” for the Annual Meeting. This means that you are entitled to notice of, and to vote at, the Annual Meeting or any continuations, adjournments, and postponements thereof if our stock records show that you owned our common stock at that time.

Whether you plan to attend the Annual Meeting or not, it is important that your shares be represented. You may vote over the Internet, via telephone or by mail. You are urged to vote in accordance with the instructions set forth in this proxy statement. We encourage you to vote by proxy so that your shares will be represented and voted at the Annual Meeting, whether or not you can attend. You will need the 16-digit control number included with the Notice, on

your proxy card or the instructions that accompany your proxy materials to attend the Annual Meeting virtually via the Internet. Submitting your vote via the Internet or by telephone or proxy card will not affect your right to vote online during the Annual Meeting.

Thank you for your continued support of Prime Medicine, Inc.

In this proxy statement, “we,” “our,” “us,” the “Company,” and “Prime” refer to Prime Medicine, Inc. and, where appropriate, our subsidiary.

On or about April , 2024, we will commence sending the Notice of Internet Availability of Proxy Materials (the “Notice”) to all stockholders of record entitled to notice of, and to vote at, the Annual Meeting.

The purposes of the Annual Meeting are:

If you are a stockholder of record and your shares are registered directly in your name, you may vote:

If the Annual Meeting is adjourned or postponed, the deadlines above may be extended.

The Annual Meeting will be a virtual meeting, which will be conducted via live webcast.

If you are a beneficial owner of shares held in “street name” by your bank, brokerage firm or other nominee, you should have received a voting instruction form provided by your bank, brokerage firm or other nominee rather than from us. If you do not have your 16-digit control number and attend the meeting online, you will be able to listen to the meeting only — you will not be able to vote or submit questions during the meeting.

Webcast replay of the Annual Meeting will be available 24 hours after the meeting has concluded for a period of one year.

During the Annual Meeting, if you have your 16-digit control number and wish to ask a question, you may do so by clicking the Q&A button on the virtual meeting platform and entering your question in the field provided in the web portal at or before the time the matters are before the Annual Meeting for consideration. During the formal portion of the meeting, all questions presented should relate directly to the proposal under discussion, which will be answered before the voting is closed. We will also hold a question and answer period at the end of the meeting, as time permits, during which time we welcome questions not relating to specific proposals. To allow us to answer questions from as many stockholders as possible, we will limit each stockholder to two questions. Questions from multiple stockholders on the same topic or that are otherwise related to a particular topic may be grouped, summarized and answered together. If questions submitted are irrelevant to the business of the Annual Meeting or are out of order or not otherwise suitable for the conduct of the Annual Meeting as determined in our reasonable judgment, we may choose not to address them. If there are any matters of individual concern to a stockholder and not of general concern to all stockholders, or if a question posed was not otherwise answered, such matters may be raised separately after the Annual Meeting.

We encourage stockholders to log into the virtual Annual Meeting at least 15 minutes prior to the start of the Annual Meeting to test their Internet connectivity. If you encounter any technical difficulties with the virtual meeting platform on the day of the Annual Meeting, please call the basic call center support number on the login screen.

Technical support will be available starting at 1:45 p.m., Eastern Time on June 12, 2024 and will remain available until thirty minutes after the meeting has finished.

Many stockholders hold their shares through a broker, bank or other nominee rather than directly in their own name. If you hold your shares in one of these ways, you are considered a beneficial owner of shares held in “street name,” not a record owner, and you therefore have no direct vote on any matter to come before the Annual Meeting. Your broker, bank or nominee will send you voting instructions for you to use in directing the broker, bank or nominee in how to vote your shares. Your broker, bank or nominee may allow you to deliver your voting instructions via the telephone or the Internet. Therefore, we urge you to carefully review and follow the voting instruction form and any other materials that you receive from that organization. If you hold your shares in multiple accounts, you should vote your shares as described in each set of proxy materials you receive.

A “broker non-vote” occurs when a broker, bank or other nominee holding shares for a beneficial owner does not vote the shares on a proposal because the broker, bank or other nominee does not have discretionary voting power for a particular item and has not received instructions from the beneficial owner regarding voting. Brokers, banks or other nominees who hold shares for the accounts of their clients have discretionary authority to vote shares if specific instructions are not given with respect to routine matters.

Although the determination of whether a broker, bank or other nominee will have discretionary voting power for a particular item is typically determined only after proxy materials are filed with the SEC, we expect that the election of each nominee for director (Proposal 1) and the approval of the amendment to our third amended and restated certificate of incorporation (Proposal 2) will be non-routine matters and that the proposal on ratification of the appointment of our independent registered public accounting firm (Proposal 3) will be a routine matter. Accordingly, if you hold your shares through a broker, bank or other nominee and you do not timely provide your broker, bank or other nominee with specific instructions on how to vote your shares, your broker, bank or other nominee will not be authorized to cast a vote on your behalf on Proposal 1 (election of each nominee for director) or Proposal 2 (approval of the amendment to our third amended and restated certificate of incorporation) but will be authorized to cast a vote on your behalf, in its discretion, on Proposal 3 (ratification of the appointment of PricewaterhouseCoopers LLP). In such cases, a “broker non-vote” may be entered with respect to your shares on Proposal 1 and Proposal 2 to reflect that your broker was present with respect to your shares at the meeting but was not exercising voting rights on your behalf with respect to those shares. Broker non-votes and abstentions will have no effect on the outcome of each such proposal, except with respect to Proposal 2. Proposal 2 (approval of the amendment to our third amended and restated certificate of incorporation) is considered to be a non-routine or a non-discretionary item. Accordingly, if you do not instruct your broker how to vote with respect to this proposal, your broker, bank, or other nominee may not vote for this proposal, and those votes will be counted as broker “non-votes.” Abstentions and broker non-votes, if any, will have the same effect on the outcome of Proposal 2 as a vote “against.” Brokers, banks and other nominees generally have discretionary authority to vote on the ratification of the appointment of an independent registered public accounting firm (Proposal 3); thus, we do not expect any broker non-votes on this matter.

To be elected, each of the directors nominated in Proposal 1 must receive a plurality of the votes properly cast on the election of directors, meaning that the four director nominees receiving the highest number of affirmative votes will be elected as directors. You may vote “for” all the director nominees, “withhold” authority to vote your shares for all the director nominees or “withhold” authority to vote your shares with respect to any one or more of the director nominees. Withholding authority to vote your shares with respect to one or more director nominees will have no effect on the election of those nominees. Broker non-votes are not considered votes cast and will have no effect on the election of the directors.

The approval of an amendment to our third amended and restated certificate of incorporation to limit the liability of certain of our officers as permitted by Delaware law in Proposal 2 must receive the affirmative vote of the majority of the outstanding shares of capital stock entitled to vote thereon, meaning that more than 50% of our outstanding

shares of common stock on the record date must vote “for” this proposal. You may vote “for,” “against” or “abstain” with respect to Proposal 2. Abstentions and broker non-votes, if any, will have the same effect as a vote “against” on Proposal 2.

Ratification of the appointment of PricewaterhouseCoopers LLC as our independent registered accounting firm for the fiscal year ending December 31, 2024 requires the affirmative vote of a majority of the votes properly cast on Proposal 3. You may vote “for,” “against” or “abstain” with respect to the ratification of the appointment of PricewaterhouseCoopers LLP. Abstentions and broker non-votes, if any, will have no effect on the outcome of the vote on this proposal.

If any other matter is presented at the Annual Meeting, your proxy provides that your shares will be voted by the proxy holder named in the proxy card in accordance with his or her best judgement. At the time this proxy statement was first made available, we knew of no matters that needed to be acted on at the Annual Meeting, other than those discussed in this proxy statement.

Our Board recommends that you vote:

If any other matter is properly brought before the Annual Meeting, the Company – through the individuals named in the Company’s proxy card and acting as the “proxy holder,” or his or her designee, and pursuant to the blanket authorization granted under the proxy – will vote your shares on that matter in accordance with the discretion and judgment of the proxy holder.

As a stockholder, you are entitled to cast one vote per share for each of the four nominees for election as directors at the Annual Meeting, but you may not cumulate your votes (in other words, you may not cast votes representing two times the number of your shares entitled to vote in favor of a single nominee). A plurality of the votes properly cast for election of a director will result in election. “Abstentions” and “broker non-votes” will not be counted as votes cast on the proposal and will have no effect on the election of directors.

As a stockholder, you are entitled to cast one vote per share for the proposal to approve the amendment to our third amended and restated certificate of incorporation at the Annual Meeting, but you may not cumulate your votes (in other words, you may not cast votes representing two times the number of your shares entitled to vote on the proposal). Proposal 2 must receive the affirmative vote of the majority of the outstanding shares of capital stock entitled to vote thereon. This means that more than 50% of our outstanding shares of common stock on record date must vote “for” this proposal. “Abstentions” and “broker non-votes,” if any, will have the same effect as a vote “against” on the outcome of Proposal 2.

A majority of the votes properly cast at the Annual Meeting will approve: (i) the proposal to ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2024; and (ii) transact any other business properly brought before the Annual Meeting.

Please note, however, that because the vote on the ratification of PricewaterhouseCoopers LLP is advisory in nature, the results of such vote will not be binding upon our Board or its committees.

We do not know of any other matters that may be presented for action at the Annual Meeting. Should any other business come before the Annual Meeting, the persons named on the Company’s proxy card will have discretionary authority to vote the shares represented by such proxies. If you hold shares through a broker, bank or other nominee as described above, they will not be able to vote your shares on any other business that comes before the Annual Meeting unless they receive instructions from you with respect to such matter.

A stockholder of record who has delivered a proxy card in response to this solicitation may revoke it before it is exercised at the Annual Meeting by executing and delivering a timely and valid later-dated proxy, by a timely and valid later Internet or telephone vote, by voting during the Annual Meeting or by giving written notice to our Secretary. Attendance at the Annual Meeting online will not have the effect of revoking a proxy unless a stockholder gives proper written notice of revocation to our Secretary before the proxy is exercised or the stockholder votes at the Annual Meeting. Beneficial owners who have directed their broker, bank or nominee as to how to vote their shares should contact their broker, bank or nominee for instructions as to how they may revoke or change those voting directions.

Our Board is making this solicitation of proxies for our Annual Meeting. We will bear all costs of such solicitation, including the cost of preparing and distributing this proxy statement and the enclosed form of proxy and including the cost of hosting the virtual Annual Meeting. After the initial distribution of this proxy statement, proxies may be solicited by mail, telephone or personally by directors, officers, employees or agents of the Company. Brokerage houses and other custodians, nominees and fiduciaries will be requested to forward soliciting materials to beneficial owners of shares held by them for the accounts of beneficial owners, and we will pay their reasonable out-of-pocket expenses.

We will remain an emerging growth company until the earliest of (i) the last day of the fiscal year in which we have total annual gross revenues of $1.235 billion or more; (ii) the last day of the fiscal year following the fifth anniversary of the date of the completion of our initial public offering in October 2022; (iii) the date on which we have issued more than $1.0 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 (the

“SEC”). We have taken advantage of reduced reporting requirements in this proxy statement. Accordingly, the information contained herein may be different from the information you receive from other public companies in which you hold stock.

Our nominating and corporate governance committee’s and our Board’s priority in selecting board members is identification of persons who will further the interests of our stockholders through their established record of professional accomplishment, the ability to contribute positively to the collaborative culture among board members, knowledge of our business, understanding of the competitive landscape, professional and personal experiences and expertise relevant to our growth strategy. Our directors hold office until their successors have been elected and qualified or until their earlier resignation or removal. Our third amended and restated certificate of incorporation and our amended and restated bylaws also provide that our directors may be removed only for cause by the affirmative vote of the holders of at least two-thirds of the votes that all our stockholders would be entitled to cast in an annual election of directors, and that any vacancy on our Board, including a vacancy resulting from an enlargement of our Board, may be filled only by vote of a majority of our directors then in office.

In accordance with the terms of our third amended and restated certificate of incorporation and our amended and restated bylaws, our Board is divided into three staggered classes of directors and each director is assigned to one of the three classes. At each annual meeting of the stockholders, one class of directors is elected for a three-year term to succeed the directors of the same class whose terms are then expiring. The terms of the directors expire upon the election and qualification of successor directors at the annual meeting of stockholders to be held during the years 2024 for Class II directors, 2025 for Class III directors, and 2026 for Class I directors. Our third amended and restated certificate of incorporation and our amended and restated bylaws provide that the number of our directors shall be fixed from time to time by a resolution of the majority of our Board.

We have not designated a chairperson or a lead director of our Board. The independent members of our Board have reviewed our Board’s leadership structure and have determined that the Company and our stockholders are well served with this structure. From time to time, our Board may appoint a standing chairperson if at such time our Board believes doing so would be in the best interest of the Company. Our Board believes that it is in the best interest of the Company for our Board to make a determination regarding whether or not to separate the roles of any chairperson and the Chief Executive Officer based on the then-current circumstances.

In considering whether to recommend any particular candidate for inclusion in our Board’s slate of recommended director nominees, our nominating and corporate governance committee takes into account the current size and composition of the Board and the needs of the Board and its committees, in addition to character, integrity, judgment, independence, skills, education, expertise, business acumen, business experience, length of service, understanding of the Company’s business and industry, conflicts of interest and other commitments. Our nominating and corporate governance committee also takes into account a candidate’s diversity and other differentiating characteristics. However, the committee does not assign any particular weight or priority to any one factor.

The biography for each of the director nominees included herein indicates each nominee’s experience, qualifications, attributes and skills that led our nominating and corporate governance committee and our Board to conclude each such director should continue to serve as a director of our Company. Our nominating and corporate governance committee and our Board believe that each of the nominees has the individual attributes and characteristics required of each of our directors, and the nominees as a group possess the skill sets and specific experience desired of our Board as a whole.

Our bylaws establish advance notice procedures with regard to stockholder proposals relating to the nomination of candidates for election as directors or new business to be brought before meetings of our stockholders. These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversary date of the

annual meeting for the preceding year. Our bylaws specify the requirements as to form and content of all stockholders’ notices.

Our Board currently consists of eight (8) members. Below is a list of the names, ages as of April 28, 2024 and classification of the individuals who currently serve as our directors.

The Board diversity matrix below provides the diversity statistics in accordance with Nasdaq Rule 5606, as self-disclosed by our directors as of April 28, 2024. Our Board satisfies the minimum objectives of Nasdaq Rule 5605(f)(3) by having at least one director who identifies as female and at least one director who identifies as a member of an Underrepresented Minority (as defined by Nasdaq Rules).

Our common stock is listed on the Nasdaq Global Market. Under the Nasdaq listing rules, independent directors must comprise a majority of a listed company’s board of directors within twelve months from the date of listing. In addition, the Nasdaq listing rules require that, subject to specified exceptions, each member of a listed company’s audit, compensation and nominating and corporate governance committees be independent within twelve months from the date of listing. Audit committee members must also satisfy additional independence criteria, including those set forth in Rule 10A-3 under the Exchange Act and compensation committee members must also satisfy the independence criteria set forth in Rule 10C-1 under the Exchange Act. Under Nasdaq listing rules, a director will only qualify as an “independent director” if, in the opinion of that company’s board of directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. In order to be considered independent for purposes of Rule 10A-3 under the Exchange Act, a member of an audit committee of a listed company may not, other than in his or her capacity as a member of the audit committee, the board of directors or any other board committee: (i) accept, directly or indirectly, any consulting, advisory or other compensatory fee from the listed company or any of its subsidiaries, other than compensation for board service; or (ii) be an affiliated person of the listed company or any of its subsidiaries. In order to be considered independent for purposes of Rule 10C-1, the board of directors must consider, for each member of a compensation committee of a listed company, 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, but not limited to: the source of compensation of the director, including any consulting advisory or other compensatory fee paid by such company to the director, and whether the director is affiliated with the company or any of its subsidiaries or affiliates.

In February of 2024, our Board undertook a review of the composition of our Board and its committees and the independence of each director. Based upon information requested from and provided by each director concerning his or her background, employment and affiliations, including family relationships, our Board has determined that all members of our Board, except Keith Gottesdiener and Jeffrey Marrazzo, are independent directors, including for purposes of Nasdaq and the SEC rules. In making that determination, our Board considered the relationships that each director has with us and all other facts and circumstances the Board deemed relevant in determining independence, including the potential deemed beneficial ownership of our capital stock by each director, including non-employee directors that are affiliated with certain of our major stockholders. We believe that the composition

and functioning of our Board and each of our committees complies with all applicable requirements of Nasdaq and the rules and regulations of the SEC. There are no family relationships among any of our executive officers and directors.

Our Board has an active role, as a whole and also at the committee level, in overseeing the management of our risks. Our Board is responsible for general oversight of risks and regular review of information regarding our risks, including credit risks, liquidity risks, operational risks and cybersecurity. The compensation committee is responsible for overseeing the management of risks relating to our executive compensation plans and arrangements. The audit committee is responsible for overseeing the management of risks relating to accounting matters and financial reporting. The nominating and corporate governance committee is responsible for overseeing the management of risks associated with the independence of our Board and potential conflicts of interest. Although each committee is responsible for evaluating certain risks and overseeing the management of such risks, the entire Board is regularly informed through discussions from committee members about such risks. Our Board believes its administration of its risk oversight function has not negatively affected our Board’s leadership structure.

Our Board has established an audit committee, a compensation committee and a nominating and corporate governance committee, each of which operates pursuant to a charter adopted by our Board. We believe that the composition and functioning of all of our committees comply with the applicable requirements of Nasdaq, the Sarbanes-Oxley Act of 2002 and SEC rules and regulations that are applicable to us. We intend to comply with future requirements to the extent they become applicable to us.

The following table describes which directors serve on each of our Board’s committees as of April 28, 2024.

Among other things, our audit committee’s responsibilities include:

All audit services and all permitted non-audit services to be provided to us by our independent registered public accounting firm must be approved in advance by our audit committee.

The members of our audit committee are Michael Kelly, Thomas Cahill and Wendy Chung. Mr. Kelly chairs the audit committee. All members of our audit committee meet the requirements for financial literacy under the applicable rules and regulations of the SEC and the Nasdaq listing rules. Our Board has determined that Mr. Kelly qualifies as an “audit committee financial expert” within the meaning of applicable SEC regulations. In making this determination, our Board considered the nature and scope of experience that Michael Kelly has previously had with public reporting companies, including service as a principal financial officer and principal accounting officer. Our Board has determined that all of the members of our audit committee satisfy the relevant independence requirements for service on the audit committee set forth in the rules of the SEC and the Nasdaq listing rules. Both our independent registered public accounting firm and management periodically meet privately with our audit committee. Our audit committee charter, which has been adopted by our Board, is available on our website.

During the fiscal year ended December 31, 2023, our audit committee met five times. The report of our audit committee is included in this proxy statement below under “Audit Committee Report.”

Among other things, our compensation committee’s responsibilities include:

The members of our compensation committee are Kaye Foster, David Schenkein and Robert Nelsen. Ms. Foster chairs the compensation committee. Each member of our compensation committee is a non-employee director, as defined in Rule 16b-3 promulgated under the Exchange Act. Our compensation committee may delegate any of the responsibilities of the full committee to subcommittees and may delegate certain responsibilities of the full committee to executive officers of the Company and other persons as may be permitted by applicable laws, rules or regulations and in accordance with the listing standards set forth by Nasdaq. Accordingly, our compensation committee has delegated authority to our chief executive officer to make equity awards under our 2022 Stock Option and Incentive Plan (as amended from time to time, the “2022 Plan”) to new hires of the Company and existing employees of the Company in connection with promotions, market adjustments, employee recognition or retention, in each case, subject to certain limitations. Our compensation committee charter, which has been adopted by our Board, is available on our website.

During the fiscal year ended December 31, 2023, our compensation committee met ten times.

Our compensation committee has engaged Alpine Rewards, LLC (“Alpine Rewards”) as its independent compensation consultant. When requested, Alpine Rewards consultants attend meetings of our compensation committee, including executive sessions in which executive compensation-related matters are discussed without the presence of our management. Alpine Rewards reports to our compensation committee and not to our management, although Alpine Rewards meets with our management for purposes of gathering information for its analyses and recommendations.

Our compensation committee assessed the independence of Alpine Rewards from management, taking into consideration relevant factors, including the absence of other services provided to our Company by Alpine Rewards, the amount of fees our Company paid to Alpine Rewards as a percentage of Alpine Rewards’ total revenue, the policies and procedures of Alpine Rewards that are designed to prevent conflicts of interest, any business or personal relationship of the individual compensation advisors employed by Alpine Rewards with any executive officer of the Company, any business or personal relationship the individual compensation advisors employed by Alpine Rewards have with any member of our compensation committee and any stock of our Company owned by Alpine Rewards or

the individual compensation advisors employed by Alpine Rewards. On the basis of that assessment and taking into consideration the independence factors that are required to be considered under applicable stock exchange rules, our compensation committee determined that no relationships existed that would create a conflict of interest or that would compromise Alpine Rewards’ independence, and that Alpine Rewards is independent pursuant to the independence standards set forth in the Nasdaq listing standards promulgated pursuant to Section 10C of the Exchange Act.

Among other things, our nominating and corporate governance committee’s responsibilities include:

The members of our nominating and corporate governance committee are David Schenkein, Wendy Chung and Thomas Cahill. Dr. Schenkein chairs our nominating and corporate governance committee. Our Board has determined that each member of our nominating and corporate governance committee satisfies the independence standards of the applicable rules of Nasdaq. Our nominating and corporate governance committee charter, which has been adopted by our Board, is available on our website.

During the fiscal year ended December 31, 2023, our nominating and corporate governance committee met two times.

Our full Board held five meetings during the year ended December 31, 2023. Each of our incumbent directors, except for Robert Nelson, attended in person or participated via teleconference at least 75% of the aggregate meetings of our Board and the committees of our Board on which he or she served during the year ended December 31, 2023 (in each case, which were held during the period for which he or she was a director and/or a member of the applicable committee and excluding any meetings in which a director was an interested party). Our non-employee directors met in executive session during each of the regularly scheduled Board meetings during the year ended December 31, 2023.

Our Corporate Governance Guidelines provide that each member of the Board is expected to make reasonable efforts to attend meetings of the Board, whether regular or special. Attendance and participation at meetings is an important component of the directors’ duties and, as such, attendance rates are taken into account by the nominating and corporate governance committee in assessing directors for renomination as directors.

Under our Corporate Governance Guidelines, each of our directors is expected to attend our annual meetings of stockholders to the extent practicable, and we encourage our directors to attend our annual meetings of stockholders. Last year, we held an annual meeting of stockholders on June 14, 2023, at which 5 directors who were members of our Board at such time were present.

Our Board adopted a Code of Business Conduct and Ethics, which applies to all of our employees, officers (including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions), agents and representatives, including directors and consultants.

We have adopted a Rule 10b5-1 trading plan policy, which permits our officers, directors, employees and certain other persons to enter into trading plans complying with Rule 10b5-1 under the Exchange Act. Generally, under these trading plans, the individual relinquishes control over the transactions once the trading plan is put into place and can only put such plans into place while the individual is not in possession of material non-public information. Accordingly, sales under these plans may occur at any time, including possibly before, simultaneously with, or immediately after significant events involving our company.

Any stockholders desiring to communicate with our Board, or one or more of our directors, may send a letter addressed to the Board of Directors of Prime Medicine, Inc., 21 Erie Street, Cambridge, MA 02139. After June 13,

2024, letters should be addressed to 60 First Street, Cambridge, MA 02141. All such letters will be promptly forwarded to the appropriate members of our Board or individual directors, as applicable.

The following table presents the total compensation for each person who served as a non-employee member of our Board during the fiscal year ended December 31, 2023. Other than as set forth in the table and described more above, we did not pay any compensation, make any equity awards or non-equity awards to, or pay any other compensation to any of the non-employee members of our Board during the fiscal year ended December 31, 2023. We reimburse non-employee members of our Board for reasonable travel and out-of-pocket expenses incurred in attending meetings of our Board and committees of our Board. Dr. Gottesdiener, who is our Chief Executive Officer, did not receive any additional compensation for his service as a director. The compensation received by Dr. Gottesdiener, as an NEO of the Company, is presented in the “2023 Summary Compensation Table” below.

We have adopted a non-employee director compensation policy designed to enable us to attract and retain, on a long-term basis, highly qualified non-employee directors. Under the policy, our non-employee directors are eligible

to receive annual cash retainers (which are payable quarterly in arrears and prorated for partial years of service) and equity awards as set forth below:

In addition, our policy provides that, upon initial election or appointment to our Board, each new non-employee director will be granted a one-time grant of a non-statutory stock option to purchase shares of our common stock equivalent to $800,000 in value on the date of such director’s election or appointment to the Board (the “Initial Director Grant”). The Initial Director Grant will vest in substantially equal annual installments over three years, subject to the non-employee director’s continued services to the Company. On the date of each annual meeting of stockholders of the Company, each non-employee director who has served as a director for at least six months prior to the annual meeting and will continue as a non-employee director following such meeting will be granted an annual award of a non-statutory stock option to purchase shares of common stock equivalent to $400,000 in value (the “Annual Director Grant”). The Annual Director Grant will vest in full on the earlier of the one-year anniversary of the grant date or on the date of our next annual meeting of stockholders, subject to the non-employee director’s continued services to the Company. Such awards are subject to fully accelerated vesting upon the sale of the Company.

The aggregate amount of compensation, including both equity compensation and cash compensation, paid to any non-employee director for service as a non-employee director in a calendar year period will not exceed $1,600,000 in the first calendar year such individual becomes a non-employee director and $1,000,000 in any other calendar year.

We reimburse all reasonable out-of-pocket expenses incurred by directors for their attendance at meetings of our Board or any committee thereof.

Employee directors receive no additional compensation for their service as a director.

In accordance with our third amended and restated certificate of incorporation and our amended and restated bylaws, our Board is divided into three staggered classes of directors, and each director is assigned to one of the three classes. At each annual meeting of the stockholders, one class of directors will be elected for a three-year term to succeed the directors of the same class whose terms are then expiring. Wendy Chung, M.D., Ph.D., Kaye Foster, Keith Gottesdiener, M.D., and Jeffrey Marrazzo are the Class II directors whose terms expire at the Annual Meeting. Each has been nominated for and has agreed to stand for re-election to our Board to serve as a Class II director of our Company for three years and until their successors are duly elected and qualified or until their earlier death, resignation or removal.

To be elected, the directors nominated via Proposal 1 must receive a plurality of the votes properly cast on the election of directors, meaning that the four director nominees for Class II directors receiving the most votes will be elected. You may vote FOR all the nominees, FOR any one of the nominees, WITHHOLD your vote from all the nominees or WITHHOLD your vote from any one of the nominees. Withheld votes and broker non-votes will have no effect on the election of directors.

The proxies will be voted in favor of the above nominees unless a contrary specification is made in the proxy. The nominees have consented to serve as our directors if elected. However, if the nominees are 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 proposal for the election of directors relates solely to the election of Class II directors nominated by our Board of Directors.

Below is a list of the names, ages as of April 28, 2024 and positions, and a brief account of the business experience of the individuals who serve as our executive officers. Andrew Anzalone is included in his capacity as a significant employee.

The biographical information pertaining to Dr. Gottesdiener, who is a director and executive officer of our Company, is included under “Director Composition,” above.

portfolio focused on biotechnology and pharmaceutical companies. Before joining Lombard Odier, from 2003 through August 2012, Dr. Reine served as a healthcare portfolio manager at various funds, including Citi Principal Strategies, SAC Capital, Trivium Capital and Alexandra Investment Management. Dr. Reine began his career in 2001 at CIBC World Markets where he worked in both biotechnology investment banking and biotechnology equity research. Dr. Reine is currently Chairman of the board of ONK Therapeutics where he has served as a board member since March 2022. Dr. Reine received his M.D. from the University of Toronto and his B.Sc. in Statistical Sciences from the University of Western Ontario.

The following table sets forth the compensation provided to our NEOs for the fiscal years ended December 31, 2023 and 2022.

Our compensation committee has the authority to engage the services of a consulting firm or other outside advisor to assist it in designing our executive compensation programs and in making compensation decisions.

During the fiscal year ended December 31, 2023, our compensation committee engaged Alpine Rewards to assist it in evaluating the Company’s executive and director compensation practices, including program design, identification of an appropriate peer group for compensation comparison purposes and providing pay benchmarking data. Alpine Rewards also provided (i) analysis and recommendations to our compensation committee regarding trends and emerging topics with respect to executive compensation; (ii) compensation programs for executives, directors and our employees generally; and (iii) stock utilization and related metrics.

Alpine reports directly to our compensation committee. Our compensation committee annually assesses its independence consistent with Nasdaq listing standards and concluded that the engagement of such consultant did not raise any conflict of interest.

Our NEOs each receive a base salary to compensate them for services rendered to our Company. The base salary payable to each NEO is intended to provide a fixed component of compensation reflecting the executive’s skill set, experience, role and responsibilities. Base salaries may be adjusted from time to time to realign salaries with market

levels after taking into account individual responsibilities, performance and experience. For the fiscal year ended December 31, 2023, the annual base salaries for our NEOs were as follows:

For the fiscal year ended December 31, 2023, each of the NEOs was eligible to earn an annual cash bonus determined by our compensation committee for NEOs other than Dr. Gottesdiener, and by our Board on the recommendation of our compensation committee for Dr. Gottesdiener, based on our corporate performance. The target annual bonus for each of our NEOs for the fiscal year ended December 31, 2023 was equal to the percentage of the executive’s respective annual base salary specified below:

We believe that long-term equity incentives provide our executives with a strong link to our long-term performance and create an ownership culture. These equity awards are a key aspect of our compensation philosophy and serve to align the interests of our executive officers with our stockholders, as they are tied to future increases in the value of our stock. Further, we believe that equity awards with a time-based vesting feature promote retention because this feature incentivizes our NEOs to remain in our employment during the vesting period. Additionally, we believe that equity awards with a performance-based vesting feature further incentivize our executive officers to achieve important milestones. Accordingly, our compensation committee periodically reviews the equity incentive compensation of our NEOs and may grant equity incentive awards to them from time to time. For additional information regarding outstanding equity awards held by our NEOs as of December 31, 2023, see the “Outstanding Equity Awards at Fiscal Year End” table below.

We do not provide significant perquisites or other personal benefits to our executive officers, including our NEOs, except for reimbursements for commuting for certain NEOs, as described above in the “2023 Summary Compensation Table.”

We maintain a retirement savings plan (“401(k) plan”) that is intended to qualify for favorable tax treatment under Section 401(a) of the Code and contains a cash or deferred feature that is intended to meet the requirements of Section 401(k) of the Code. U.S. employees are generally eligible to participate in the 401(k) plan, subject to certain criteria. Participants may make pre-tax and certain after-tax (Roth) salary deferral contributions to the plan from their eligible earnings up to the statutorily prescribed annual limit under the Code. Participants who are 50 years of age or older may contribute additional amounts based on the statutory limits for catch-up contributions. Participant contributions are held in trust as required by law. We provide matching contributions equal to 50% of an employee’s contributions, subject to a maximum of 6% of eligible compensation.

In connection with our initial public offering, we entered into new employment agreements with our NEOs that were effective as of July 2022.

Each of Dr. Gottesdiener, Dr. Lee and Dr. Duffield are subject to standard confidentiality and nondisclosure, assignment of intellectual property work product and post-termination non-solicitation of employees, consultants and customers covenants and, in certain circumstances, non-competition covenants.

The employment agreement with Dr. Gottesdiener (the “Gottesdiener Employment Agreement”) provides for at-will employment. The agreement also sets forth initial base salary, initial annual target bonus and eligibility to participate in our benefit plans generally. In addition, pursuant to Amendment No. 1 to the Gottesdiener Employment Agreement, Dr. Gottesdiener is entitled to reimbursement for commuting expenses, which include all reasonable costs for his commute between his family’s residence in New York, New York and our corporate headquarters in Cambridge, Massachusetts.

Pursuant to the Gottesdiener Employment Agreement, in the event Dr. Gottesdiener is terminated by us without “cause” or he resigns for “good reason” (as such terms are defined in the Gottesdiener Employment Agreement), in each case subject to the delivery of and compliance with a fully effective separation agreement that shall include, without limitation, a release of claims, reaffirmation of applicable restrictive covenants and, in the Company’s discretion, a one year non-competition agreement, Dr. Gottesdiener will be entitled to (i) an amount equal to the sum of (A) 12 months of his then-current base salary plus (B) 1.0 times his target annual bonus for the then current year, in each case subject to reductions by any amount received by him pursuant to a restrictive covenant agreement, (ii) subject to Dr. Gottesdiener’s copayment of premium amounts at the applicable active employees’ rate and proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had he remained employed by us until the earliest of (A) 12 months following his termination, (B) his eligibility for group medical plan benefits under any other employer’s group medical plan or (C) the end of his COBRA health continuation period. These amounts shall be paid out in substantially equal installments in accordance with the Company’s payroll practice over a period of 12 months. In addition, subject to the delivery of the fully effective separation agreement, the bonus amount (if any) that Dr. Gottesdiener would have been paid if he had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives, will be paid to Dr. Gottesdiener on the date the Company’s other executives receive their bonuses. In addition, the Company has agreed to negotiate in good faith a non-exclusive limited consulting relationship with Dr. Gottesdiener for a period up to one year pursuant to which Dr. Gottesdiener will receive no cash compensation other than severance benefits.

In the event Dr. Gottesdiener is terminated by us without cause or he resigns for good reason, in each case within 12 months following a change in control (as defined in the Gottesdiener Employment Agreement), or 3 months prior to such change in control, subject to the delivery of and compliance with a fully effective separation agreement as described above, Dr. Gottesdiener will be entitled to the following, in lieu of the benefits above: (i) a lump sum cash payment equal to the sum of (A) 18 months of his then-current base salary (or his base salary in effect immediately prior to the change in control, if higher) plus (B) 1.5 times his target annual bonus for the then current year (or target in effect immediately prior to the change in control, if higher), in each case subject to reductions by any amount

received by him pursuant to a restrictive covenant agreement, (ii) subject to Dr. Gottesdiener’s copayment of premium amounts at the applicable active employees’ rate and proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had he remained employed by us until the earliest of (A) 18 months from the date of his separation, (B) his eligibility for group medical plan benefits under any other employer’s group medical plan or (C) the end of his COBRA health continuation period, and (iii) the bonus amount (if any) that Dr. Gottesdiener would have been paid if he had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives. In addition, in the event Dr. Gottesdiener is terminated by us without cause or he resigns for good reason, in each case within 12 months following a change in control, or 3 months prior to such change in control, all of the then-outstanding and unvested portion of his stock options and other stock-based awards that (i) are subject solely to time-based vesting or (ii) were granted to Dr. Gottesdiener prior to the effective date of the Gottesdiener Employment Agreement and are subject to performance-based vesting shall become fully vested and exercisable or nonforfeitable immediately as of the date of termination or, if later, the change in control event, with any such performance-based awards vesting at target.

The payments and benefits provided under the Gottesdiener Employment Agreement in connection with a change in control may not be eligible for federal income tax deduction for the Company pursuant to Section 280G of the Code. These payments and benefits may also be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Gottesdiener in connection with a change in control would be subject to the excise tax imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after-tax benefit to him.

Pursuant to the Lee Employment Agreement, in the event Dr. Lee is terminated by us without “cause” or she resigns for “good reason” (as such terms are defined in the Lee Employment Agreement), in each case subject to the delivery of and compliance with a fully effective separation agreement that shall include, without limitation, a release of claims, reaffirmation of applicable restrictive covenants and, in the Company’s discretion, a one year non-competition agreement, Dr. Lee will be entitled to (i) an amount equal to the sum of (A) 9 months of her then-current base salary plus (B) 0.75 times her target annual bonus for the then current year, in each case subject to reductions by any amount received by her pursuant to a restrictive covenant agreement, and (ii) subject to Dr. Lee’s co-payment of premium amounts at the applicable active employees’ rate and proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had she remained employed by us until the earliest of (A) 9 months following her termination, (B) her eligibility for group medical plan benefits under any other employer’s group medical plan or (C) the end of her COBRA health continuation period. These amounts shall be paid out in substantially equal installments in accordance with the Company’s payroll practice over a period of 9 months. In addition, subject to the delivery of the fully effective separation agreement, the bonus amount (if any) that Dr. Lee would have been paid if she had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives, will be paid to Dr. Lee on the date the Company’s other executives receive their bonuses.

In the event Dr. Lee is terminated by us without cause or she resigns for good reason, in each case within 12 months following a change in control (as defined in the Lee Employment Agreement), subject to the delivery of and compliance with a fully effective separation agreement (as described above), Dr. Lee will be entitled to the following, in lieu of the benefits above: (i) a lump sum cash payment equal to the sum of (A) 12 months of her then-current base salary (or her base salary in effect immediately prior to the change in control, if higher) plus (B) 1.0 times her target annual bonus for the then current year (or target in effect immediately prior to the change in control, if higher), in each case subject to reductions by any amount received by her pursuant to a restrictive covenant agreement, (ii) subject to Dr. Lee’s co-payment of premium amounts at the applicable active employees’ rate and

proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had she remained employed by us until the earliest of (A) 12 months from the date of her separation, (B) her eligibility for group medical plan benefits under any other employer’s group medical plan or (C) the end of her COBRA health continuation period, and (iii) the bonus amount (if any) that Dr. Lee would have been paid if she had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives. In addition, in the event Dr. Lee is terminated by us without cause or she resigns for good reason, in each case within 12 months following a change in control (as defined in the Lee Employment Agreement), all of the then-outstanding and unvested portion of her stock options and other stock-based awards that (i) are subject solely to time-based vesting or (ii) were granted to Dr. Lee prior to the effective date of the Lee Employment Agreement and are subject to performance-based vesting shall become fully vested and exercisable or non-forfeitable immediately as of the date of termination, with any such performance-based awards vesting at target.

The payments and benefits provided under the Lee Employment Agreement in connection with a change in control may not be eligible for federal income tax deduction for the Company pursuant to Section 280G of the Code. These payments and benefits may also be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Lee in connection with a change in control would be subject to the excise tax imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after-tax benefit to her.

Pursuant to the Duffield Employment Agreement, in the event Dr. Duffield is terminated by us without “cause” or he resigns for “good reason” (as such terms are defined in the Duffield Employment Agreement), in each case subject to the delivery of and compliance with a fully effective separation agreement that shall include, without limitation, a release of claims, reaffirmation of applicable restrictive covenants and, in the Company’s discretion, a one year non-competition agreement, Dr. Duffield will be entitled to (i) an amount equal to the sum of (A) 9 months of his then-current base salary plus (B) 0.75 times his target annual bonus for the then current year, in each case subject to reductions by any amount received by him pursuant to a restrictive covenant agreement, (ii) subject to Dr. Duffield’s co-payment of premium amounts at the applicable active employees’ rate and proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had he remained employed by us until the earliest of (A) 9 months following his termination, (B) his eligibility for group medical plan benefits under any other employer’s group medical plan or (C) the end of his COBRA health continuation period. These amounts shall be paid out in substantially equal installments in accordance with the Company’s payroll practice over a period of 9 months. In addition, subject to the delivery of the fully effective separation agreement, the bonus amount (if any) that Dr. Duffield would have been paid if he had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives, will be paid to Dr. Duffield on the date the Company’s other executives receive their bonuses.

In the event Dr. Duffield is terminated by us without cause or he resigns for good reason, in each case within 12 months following a change in control (as defined in the Duffield Employment Agreement), subject to the delivery of and compliance with a fully effective separation agreement (as described above), Dr. Duffield will be entitled to the following, in lieu of the benefits above: (i) a lump sum cash payment equal to the sum of (A) 12 months of his then-current base salary (or his base salary in effect immediately prior to the change in control, if higher) plus (B) 1.0 times his target annual bonus for the then current year (or target in effect immediately prior to the change in control, if higher), in each case subject to reductions by any amount received by him pursuant to a restrictive covenant agreement, (ii) subject to Dr. Duffield’s co-payment of premium amounts at the applicable active employees’ rate and proper election to continue COBRA health coverage, payment of the portion of the premium equal to the amount we would have paid to provide health insurance had he remained employed by us until the earliest of (A) 12 months from the date of his separation, (B) his eligibility for group medical plan benefits under any other

employer’s group medical plan or (C) the end of his COBRA health continuation period, and (iii) the bonus amount (if any) that Dr. Duffield would have been paid if he had remained employed through the payment date, if such termination occurs on or after January 1 but before the date bonuses are paid for the prior year to the Company’s other executives. In addition, in the event Dr. Duffield is terminated by us without cause or he resigns for good reason, in each case within 12 months following a change in control, all of the then-outstanding and unvested portion of his stock options and other stock-based awards that are subject solely to time-based vesting shall become fully vested and exercisable or non-forfeitable immediately as of the date of termination, with any such performance-based awards vesting at target.

The payments and benefits provided under the Duffield Employment Agreement in connection with a change in control may not be eligible for federal income tax deduction for the Company pursuant to Section 280G of the Code. These payments and benefits may also be subject to an excise tax under Section 4999 of the Code. If the payments or benefits payable to Dr. Duffield in connection with a change in control would be subject to the excise tax imposed under Section 4999 of the Code, then those payments or benefits will be reduced if such reduction would result in a higher net after-tax benefit to him.

We operate in accordance with a written charter adopted by our Board and reviewed annually by the audit committee. We are responsible for overseeing the quality and integrity of the Company’s accounting, auditing and financial reporting practices. In accordance with the rules of the SEC and Nasdaq, the audit committee is composed entirely of members who are independent, as defined by the listing standards of Nasdaq and the Company’s Corporate Governance Guidelines. Further, our Board has determined that Michael Kelly is an audit committee financial expert as defined by the rules of the SEC.

The audit committee met five times during the fiscal year ended December 31, 2023 with the Company’s management and PricewaterhouseCoopers LLP, the Company’s independent registered public accounting firm, including, but not limited to, to review and discussion of the Company’s quarterly financial statements and related disclosures, and the inclusion of the Company’s audited financial statements in the Company’s Annual report on Form 10-K for the fiscal year ended December 31, 2023.

We believe that we fully discharged our oversight responsibilities as described in our charter, including with respect to the audit process. We reviewed and discussed our audited financial statements for the fiscal year ended December 31, 2023 with management and PricewaterhouseCoopers LLP. Management has the responsibility for the preparation of the Company’s financial statements, and PricewaterhouseCoopers LLP has the responsibility for the audit of those statements. The audit committee discussed with PricewaterhouseCoopers LLP the matters required to be discussed by Public Company Accounting Oversight Board, or PCAOB, Auditing Standard No. 1301 and the SEC regarding the independent registered public accounting firm’s communications with the audit committee concerning independence. We received the written disclosures and the letter from PricewaterhouseCoopers LLP pursuant to Rule 3526, Communication with Audit Committees Concerning Independence, of the PCAOB concerning any relationships between PricewaterhouseCoopers LLP and the Company and the potential effects of any disclosed relationships on PricewaterhouseCoopers LLP’s independence, and discussed with PricewaterhouseCoopers LLP its independence. We reviewed with PricewaterhouseCoopers LLP their audit plans, audit scope, identification of audit risks and their audit efforts, and discussed and reviewed the results of PricewaterhouseCoopers LLP’s examination of the Company’s financial statements both with and without management.

Based on these reviews and discussions with management and PricewaterhouseCoopers LLP, we approved the inclusion of the Company’s audited financial statements in its Annual Report on Form 10-K for the fiscal year ended December 31, 2023 for filing with the SEC. We also have selected PricewaterhouseCoopers LLP as the independent registered public accounting firm for the fiscal year ending December 31, 2024, subject to ratification by the Company’s stockholders.

Other than the compensation arrangements for our NEOs and our directors described elsewhere in this proxy statement under “Executive Compensation” and “Director Compensation,” set forth below is a description of transactions or series of transactions since January 1, 2022, to which we were or will be a party, and in which:

Our 5% stockholders and their affiliates purchased an aggregate of 2,000,000 shares of our common stock in our initial public offering in October 2022 at the initial public offering price. The following table sets forth the number of shares of our common stock purchased by 5% stockholders and their affiliates and the aggregate purchase price paid for such shares.

(1) David Schenkein serves as a member of our board of directors and is an affiliate of GV, of which GV 2019, L.P. is an affiliated fund. Entities affiliated with GV collectively hold more than 5 percent of our voting securities.

(2) Robert Nelsen serves as a member of our board of directors and is an affiliate of ARCH Venture Partners, of which ARCH Venture Fund X Overage, L.P. and ARCH Venture Fund X, L.P. are affiliated funds. Entities affiliated with ARCH Venture Partners collectively hold more than 5 percent of our voting securities.

Our 5% stockholders and their affiliates purchased an aggregate of 7,200,000 shares of our common stock in our follow-on public offering in February 2024 at the public offering price. The following table sets forth the number of shares of our common stock purchased by 5% stockholders and their affiliates and the aggregate purchase price paid for such shares.

Pursuant to a consulting agreement with David Liu (the “Liu Consulting Agreement”), we agreed to pay Dr. Liu an annual fee of $150,000 and to reimburse Dr. Liu’s reasonable business expenses. Dr. Liu is a beneficial owner of more than 5% of our voting securities. Dr. Liu agreed to provide services, including serving as Chairman of our Scientific Advisory Board and advisory services related to any and all gene editing and related technology for any

and all human or prophylactic uses, including without limitation, participation in corporate and research and development strategy sessions, recruiting and interviewing activities, finding and establishing laboratory space, advising on the design of experiments and other research and development activities.

Pursuant to the Liu Consulting Agreement, for the term of the Liu Consulting Agreement and six months thereafter, Dr. Liu cannot directly provide material services to any third party in the field of gene editing for therapeutics or become an owner, partner, shareholder, consultant, agent, employee or co-venturer of any third party that has committed, or intends to commit, significant resources to that field, with certain exceptions, including a previous commitment with respect to Beam Therapeutics Inc., or Beam (see below).

The Liu Consulting Agreement does not prevent David Liu from conducting research funded by a third-party sponsor at the Howard Hughes Medical Institute, Harvard University or Broad Institute, Inc., or collectively, the Institutions, provided that any inventions conceived in the course of such research will be owned by such Institution. Furthermore, David Liu is not restricted from publishing the results of such research or providing education, clinical or other such services for an Institution. Additionally, pursuant to a consulting agreement entered into between Dr. Liu and Beam in March 2017 (the “Beam Consulting Agreement”), Dr. Liu is permitted to provide consulting services to Beam, subject to certain limitations, one of which includes not providing Beam services related to our Prime Editing technology. If there is any conflict between the Liu Consulting Agreement and the Beam Consulting Agreement, the Beam Consulting Agreement prevails. The current term of the Liu Consulting Agreement runs through September 2025, following which it may be terminated by either party with 30 days prior notice. Between January 1, 2022 and December 31, 2023, we paid Dr. Liu $300,000 under the Liu Consulting Agreement.

Pursuant to an advisory services agreement with Jeffrey Marrazzo (the “Marrazzo Agreement”), dated February 29, 2024, Mr. Marrazzo agreed to provide certain professional services to the Company in addition to his service as a Board member, and we agreed to pay Mr. Marrazzo an annual fee of $50,000 per year in addition to the grant of an option to purchase 250,000 shares of the Company’s common stock.

The term of the Marrazzo Agreement runs through February 2025 and may be terminated or extended by mutual written agreement. If the Company terminates the Marrazzo Agreement without “cause,” the Administrator of the 2022 Plan will accelerate the vesting of the option such that the pro rata portion of the option will vest and be immediately exercisable.

We have entered into agreements to indemnify our directors and executive officers. These agreements, among other things, require us to indemnify these individuals for certain expenses (including attorneys’ fees), judgments, fines and settlement amounts reasonably incurred by such person in any action or proceeding, including any action by or in our right, on account of any services undertaken by such person on behalf of our company or that person’s status as a member of our Board to the maximum extent allowed under Delaware law.

Our Board reviews and approves transactions with directors, officers and holders of 5 percent or more of our voting securities and their affiliates, each a related party. The material facts as to the related party’s relationship or interest in the transaction were disclosed to our Board prior to their consideration of such transaction, and the transaction was not considered approved by our Board unless a majority of the directors who are not interested in the transaction approved the transaction. Further, when stockholders were entitled to vote on a transaction with a related party, the material facts of the related party’s relationship or interest in the transaction were disclosed to the stockholders, who were obligated to approve the transaction in good faith.

In connection with our October 2022 initial public offering, we adopted a written related party transactions policy that provides that such transactions must be approved by our audit committee. Pursuant to this policy, the audit committee has the primary responsibility for reviewing and approving or disapproving “related party transactions,” which are transactions between us and related persons in which the aggregate amount involved exceeds or may be expected to exceed $120,000 and in which a related person has or will have a direct or indirect material interest. In reviewing any such proposal, our audit committee or other committee of independent directors are to consider the relevant facts of the transaction, including the risks, costs and benefits to us and whether the transaction is on terms no less favorable than terms generally available to an unaffiliated third party under the same or similar circumstances. For purposes of this policy, a related person is defined as a director, executive officer, nominee for director, or greater than 5 percent beneficial owner of our common stock, in each case since the beginning of the most recently completed year, and their immediate family members.

In August 2022, the State of Delaware, which is our state of incorporation, enacted legislation that enables Delaware companies to limit the liability of certain of their officers in limited circumstances pursuant to amended Section 102(b)(7) of the General Corporation Law of the State of Delaware (the “DGCL”). Amended DGCL Section 102(b)(7) permits exculpation for direct claims brought by stockholders for breach of an officer’s fiduciary duty of care, including class actions, but does not eliminate officers’ monetary liability for breach of fiduciary duty claims brought by the corporation itself or for derivative claims brought by stockholders in the name of the corporation. Furthermore, the limitation on liability does not apply to breaches of the duty of loyalty, acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law, or any transaction in which the officer derived an improper personal benefit.

Our Board believes it is appropriate for public companies in states that allow exculpation of officers to have exculpation clauses in their certificates of incorporation. Adopting an officer exculpation provision that aligns with the protections afforded under the DGCL could prevent protracted or otherwise meritless litigation that distracts from our primary objective of creating stockholder value over the long term. The nature of the role of directors and officers often requires them to make decisions on crucial matters. Frequently, directors and officers must make decisions in response to time-sensitive opportunities and challenges, which can create substantial risk of investigations, claims, actions, suits, or proceedings seeking to impose liability on the basis of hindsight, especially in the current litigious environment and regardless of merit. Our Board believes that limiting concern about personal liability will empower officers to best exercise their business judgment in furtherance of stockholder interests without the distraction of potentially being subject to claims following actions taken in good faith.

In addition, our Board believes it is important to provide protection to officers to the extent permitted by the DGCL to attract and retain executive talent. This protection has long been afforded to directors and other public companies have updated their governing documents to align with amended Section 102(b)(7) of the DGCL, and we expect this practice to continue. The corporate law codes of several other states already permit corporations to exculpate officers in a similar manner to Section 102(b)(7). Therefore, our ability to attract and retain highly qualified officer candidates may be adversely impacted if we do not implement the expanded protections now offered under Delaware law. Further, our Board believes that the proposed amendment to our certificate of incorporation would not negatively impact shareholder rights, particularly taking into account the narrow class and type of claims for which officers’ liability would be exculpated.

Our third amended and restated certificate of incorporation currently provides for the exculpation of directors, but does not include a provision that allows for the exculpation of officers. The Exculpation Amendment would amend our third amended and restated certificate of incorporation by adding a new article to reflect new Delaware law provisions regarding exculpation of officers as follows:

The proposed Certificate of Amendment to our third amended and restated certificate of incorporation (the “Certificate of Amendment”), reflecting the foregoing Exculpation Amendment is attached as Appendix A to this proxy statement.

If the proposed Exculpation Amendment is approved by our stockholders, it will become effective immediately upon the filing of the Certificate of Amendment with the Secretary of State of the State of Delaware, which we expect to file promptly after the Annual Meeting. Other than the addition of Article X, the remainder of our certificate of incorporation will remain unchanged after effectiveness of the Certificate of Amendment. If the proposed Exculpation Amendment is not approved by our stockholders, our certificate of incorporation will remain unchanged. In accordance with the DGCL, our board of directors may elect to abandon the proposed Exculpation Amendment without further action by the stockholders at any time prior to the effectiveness of the filing of the Certificate of Amendment with the Secretary of State of the State of Delaware, notwithstanding stockholder approval of the proposed Exculpation Amendment. The proposed Exculpation Amendment is not being proposed in response to any specific resignation, threat of resignation or refusal to serve by any officer.

The affirmative vote of holders of a majority of the shares outstanding and entitled to vote as of the record date is required to approve the Exculpation Amendment. Abstentions and broker non-votes will have the effect of a vote against the Exculpation Amendment.

We are asking our stockholders to ratify our audit committee’s appointment of PricewaterhouseCoopers LLP (“PwC”), as our independent registered public accounting firm for the fiscal year ending December 31, 2024. PwC has served as our independent registered public accounting firm since 2021.

Our audit committee annually reviews our independent registered public accounting firm’s independence, including reviewing all relationships between our independent registered public accounting firm and us and any disclosed relationships or services that may affect the objectivity and independence of our independent registered public accounting firm, and our independent registered public accounting firm’s performance. Although ratification is not required by our amended and restated bylaws or otherwise, our Board is submitting the appointment of PwC to our stockholders for ratification as a matter of good corporate practice. If the appointment is not ratified, our audit committee will consider whether it is appropriate to select another independent registered public accounting firm. Even if the appointment is ratified, our audit committee in its discretion may appoint a different registered public accounting firm at any time during the year if the audit committee determines that such a change would be in the best interests of our Company and our stockholders.

PwC served as independent registered public accounting firm for our Company with respect to the audit of the Company’s consolidated financial statements for the fiscal year ended December 31, 2023 and has been engaged by our audit committee to serve as our independent registered public accounting firm with respect to the audit of our consolidated financial statements for the fiscal year ending December 31, 2024. Representatives of PwC will be present at the Annual Meeting, will have the opportunity to make a statement if they desire to do so, and will be available to respond to appropriate questions from stockholders.

Our audit committee (or a subcommittee delegated to it by the audit committee) approves in advance all services proposed to be performed for our Company or its subsidiaries by any independent registered public accounting firm that performs (or proposes to perform) audit, review or attest services for our Company or its subsidiaries.

Ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2024 requires the affirmative vote of a majority of the votes properly cast on the proposal. Abstentions and broker non-votes, if any, will have no effect on the outcome of the vote on this proposal.

The following table sets forth information, as of March 31, 2024, unless otherwise indicated, regarding the beneficial ownership of our common stock for (i) stockholders who beneficially owned more than 5% of our common stock, (ii) each of our directors and NEOs, and (iii) all of our directors and executive officers as a group.

The number of shares beneficially owned by each stockholder is determined under rules issued by the SEC. Under these rules, a person is deemed to be a “beneficial” owner of a security if that person has or shares voting power or investment power, which includes the power to dispose of or to direct the disposition of such security. Except as indicated in the footnotes below, we believe, based on the information furnished to us, that the individuals and entities named in the table below have sole voting and investment power with respect to all shares of common stock beneficially owned by them, subject to any applicable community property laws.

In computing the number of shares beneficially owned by an individual or entity, shares of common stock subject to options, warrants, restricted stock units or other rights held by such person that are currently exercisable or have vested or that will become exercisable or will have vested within 60 days of March 31, 2024 are considered outstanding, although these shares are not considered outstanding for purposes of computing the percentage ownership of any other person. On March 31, 2024, there were 120,021,274 shares of our common stock outstanding. Unless noted otherwise, the address of all listed stockholders is 21 Erie Street, 2nd Floor, Cambridge, MA 02139.

In addition, to comply with the universal proxy rules, stockholders who intend to solicit proxies in support of director nominees other than the Company’s nominees must provide notice by the same deadline noted herein to submit a notice of nomination at an annual meeting of stockholders. Such notice must comply with the additional requirements of Rule 14a-19(b).

Upon written request, the Company will provide without charge to each stockholder who does not otherwise receive a copy of our Company’s annual report to stockholders a copy of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023, as filed with the SEC, except for exhibits.

Please address all requests before June 13, 2024 to:

SEC rules concerning the delivery of annual disclosure documents allow us or your broker to send a single notice or, if applicable, a single set of our proxy materials to any household at which two or more of our stockholders reside, if we or your broker believe that the stockholders are members of the same family, unless we have received contrary instructions from one or more of the stockholders. This practice, referred to as “householding,” benefits both you

and us. It reduces the volume of duplicate information received at your household and helps to reduce our expenses. The rule applies to our notices, annual reports, proxy statements and information statements.

We will undertake to deliver promptly, upon written or oral request, a separate copy to a stockholder at a shared address to which a single copy of the notice or proxy materials was delivered. You may make a written or oral request by sending a notification to our Secretary at the address above, providing your name, your shared address, and the address to which we should direct the additional copy of the notice or proxy materials. Multiple stockholders sharing an address who have received one copy of a mailing and would prefer us to mail each stockholder a separate copy of future mailings should contact us at our principal executive offices. Additionally, if current stockholders with a shared address received multiple copies of a mailing and would prefer us to mail one copy of future mailings to stockholders at the shared address, notification of that request may also be made through our principal executive offices. Stockholders who participate in householding will continue to have access to and utilize separate proxy voting instructions.