321 Summer Street, Suite 400

Boston, Massachusetts 02210

(857) 330-4340

NOTICE OF 20212023 ANNUAL MEETING OF STOCKHOLDERS

To Be Held on June 23, 202113, 2023

Dear Stockholders:

You are cordially invited to virtually attend the 20212023 annual meeting of stockholders, or the Annual Meeting, of Inozyme Pharma, Inc. To support the health and well-being of our stockholders, employees and directors in light of the coronavirus (COVID-19) pandemic, theThe Annual Meeting will be held via the Internet at a virtual audio web conference at https://www.proxydocs.com/INZY on Wednesday,Tuesday, June 23, 202113, 2023 at 9:10:00 a.m., Eastern Time.

Only stockholders who owned shares of our common stock at the close of business on April 26, 202117, 2023 are entitled to notice of and to vote at the Annual Meeting or any adjournment thereof.

At the Annual Meeting, the stockholders will consider and vote on the following matters:

The Annual Meeting will be a “virtual meeting” of stockholders, which will be conducted exclusively via the Internet at a virtual web conference. There will not be a physical meeting location, and stockholders will not be able to attend the Annual Meeting in person. This means that you can attend the Annual Meeting online, vote your shares during the online meeting and submit questions during the online meeting. In order to attend the meeting and vote your shares electronically during the meeting, you must register in advance at https://www.proxydocs.com/INZY prior to the deadline of June 21, 202111, 2023 at 5:00 p.m., Eastern Time. Upon completing your registration, you will receive further instructions via email, including your unique links that will allow you to attend the Annual Meeting online, vote your shares and submit questions. We believe that hosting a “virtual meeting” will enable greater stockholder attendance and participation from any location around the world.

You can find more information, including the nominees for director, in the proxy statement for the Annual Meeting, which is available for viewing, printing and downloading at https://www.proxydocs.com/INZY. The board of directors recommends that you vote “FOR” each of the Class IIII directors (Proposal 1) and “FOR” the ratification of the appointment of the independent registered public accounting firm (Proposal 2) as outlined in the attached proxy statement.

We are pleased to comply with the rules of the Securities and Exchange Commission that allow companies to distribute their proxy materials over the Internet under the “notice and access” approach. As a result, we will send to our stockholders a Notice of Internet Availability of Proxy Materials, or the Notice of Availability, instead of a paper copy of the proxy statement and our annual report for the fiscal year ended December 31, 2020,2022, or the 20202022 Annual Report. We plan to mail the Notice of Availability on or before May 7, 2021,April 27, 2023, and the Notice of Availability contains instructions on how to access our proxy materials over the Internet. The Notice of

Availability also contains instructions on how each of our stockholders can receive a paper copy of our proxy materials, including the proxy statement, our 20202022 Annual Report, and a form of proxy card.

Your vote is important regardless of the number of shares you own. Whether or not you expect to virtually attend the Annual Meeting, please vote your shares to ensure your representation and the presence of a quorum at the Annual Meeting. If you are a stockholder of record, you may vote your shares prior to the Annual Meeting on the Internet by visiting https://www.proxypush.com/INZY, by telephone by calling 1-866-509-1045 and following the recorded instructions, or by completing, signing, dating, and returning a proxy card. If you vote prior to the Annual Meeting and then decide to attend the Annual Meeting and vote your shares online during the Annual Meeting, you may still do so. Your proxy is revocable in accordance with the procedures set forth in the proxy statement.

If your shares are held in “street name,” that is, held for your account by a bank, broker or other nominee, you will receive instructions from the bank, broker or other nominee that you must follow for your shares to be voted. Stockholders that hold shares in “street name” must demonstrate proof of beneficial ownership to virtually attend the Annual Meeting and must obtain a legal proxy from their bank, broker or other nominee to vote during the Annual Meeting.

A list of stockholders as of the close of business on the record date will be available for examination by our stockholders of record during the Annual Meeting using the unique link provided via email following the completion of registration. Further information about how to register for the Annual Meeting, attend the Annual Meeting online, vote your shares and submit questions is included in the accompanying proxy statement.

Boston, Massachusetts

April 27, 2021

Douglas A. Treco

Chief Executive Officer

Boston, Massachusetts

April 27, 2023

Important Notice Regarding Internet Availability of Proxy Materials for the 20212023 Annual Meeting of Stockholders to be held on June 23, 2021: 13, 2023: The attached proxy statement and our 20202022 Annual Report to stockholders, which includes our annual report on Form 10-K for the fiscal year ended December 31, 2020,2022, are available for viewing, printing and downloading at https://www.proxydocs.com/INZY. These documents are also available to any stockholder who wishes to receive a paper copy upon written request to Inozyme Pharma, Inc., 321 Summer Street, Suite 400, Boston, Massachusetts 02210. This proxy statement and our annual report on Form 10-K for the fiscal year ended December 31, 20202022 are also available on the SEC’s website at http://www.sec.gov.

INOZYME PHARMA, INC.

PROXY STATEMENT

TABLE OF CONTENTS

stockholder upon written request to Inozyme Pharma, Inc., 321 Summer Street, Suite 400, Boston, Massachusetts 02210. This proxy statement and our annual report on Form 10-K for the fiscal year ended December 31, 20202022 are also available on the SEC’s website at http://www.sec.gov.

IMPORTANT INFORMATION ABOUT THE ANNUAL MEETING AND VOTING

Purpose of the Annual Meeting

At the Annual Meeting, our stockholders will consider and vote on the following matters:

As of the date of this proxy statement, we are not aware of any business to come before the meetingAnnual Meeting other than the first two items noted above.

Board of Directors Recommendation

Our board of directors unanimously recommends that you vote:

FOR the election of the three nominees to serve as Class IIII directors on our board of directors, each for a three-year term expiring at the 20242026 annual meeting of stockholders; and

FOR the ratification of the appointment of Ernst & Young LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2021.2023.

Availability of Proxy Materials

The proxy materials, including this proxy statement, a proxy card and our 20202022 Annual Report are available for viewing, printing and downloading on the Internet at https://www.proxydocs.com/INZY. If you would like to receive a paper copy of our proxy materials, you should follow the instructions for requesting paper materials in the Notice of Availability.

Who Can Vote at the Annual Meeting?

Only stockholders who owned shares of our common stock at the close of business on the record date of April 26, 202117, 2023 are entitled to receive notice of the Annual Meeting and to vote the shares of our common stock that they held on that date. As of April 26, 2021,17, 2023, there were 23,473,70343,765,485 shares of our common stock issued and outstanding. Each share of common stock is entitled to one vote on each matter properly brought before the Annual Meeting.

Difference Between a “Stockholder of Record” and a Beneficial Owner of Shares Held in “Street Name”

Stockholder of Record. If your shares are registered directly in your name with our transfer agent, Computershare Trust Company, N.A., then you are considered the “stockholder of record” of those shares. In this case, your Notice of Availability has been sent to you directly by us. You may vote your shares by proxy prior to the Annual Meeting by following the instructions contained in the Notice of Availability and in the section titled “How to Vote” below.

Beneficial Owner of Shares Held in Street Name. If your shares are held by a bank, broker or other nominee, then you are considered the beneficial owner of those shares, which are held in “street name.” In this case, your Notice of Availability will be sent to you by that organization. The organization holding your shares is considered the stockholder of record for purposes of voting at the Annual Meeting. As the beneficial owner, you have the right to instruct that organization as to how to vote the shares held in your account by following the instructions contained on the voting instruction form provided to you by that organization.

Why Did I Receive a Notice in the Mail Regarding the Internet Availability of Proxy Materials instead of a Full Set of Proxy Materials?

We are pleased to comply with the SEC rules that allow companies to distribute their proxy materials over the Internet under the “notice and access” approach. As a result, we are sending our stockholders and beneficial owners of our common stock a copy of the Notice of Availability instead of paper copies of this proxy statement, our proxy card, and our 20202022 Annual Report. We will send the Notice of

Availability on or before May 7, 2021.April 27, 2023. Detailed instructions on how to access these materials via the Internet may be found in the Notice of Availability. This proxy statement and our 20202022 Annual Report are available for viewing, printing and downloading on the Internet at https://www.proxydocs.com/INZY.

Why is the Annual Meeting a Virtual, Online Meeting?

To support the health and well-being of our stockholders, employees and directors in light of the COVID-19 pandemic, ourOur Annual Meeting will be a virtual meeting of stockholders where stockholders will participate by accessing a website using the Internet. We believe that hosting a virtual meeting will facilitate stockholder attendance and participation at our Annual Meeting by enabling stockholders to safely participate from any location around the world. Our virtual meeting will be governed by our Rules of Conduct and Procedures which will be posted at https://www.proxydocs.com/INZY in advance of the meeting. We have designed the virtual annual meeting to provide our stockholders with the same rights and opportunities to participate as stockholders would have at an in person meeting, including the right to vote and ask questions during the during the meeting through the virtual meeting platform.

How Do I Attend the Virtual Annual Meeting?

The Annual Meeting will be a virtual meeting and you may not attend in person. In order to attend the meeting online, you must register in advance at https://www.proxydocs.com/INZY prior to the deadline of June 21, 202111, 2023 at 5:00 p.m., Eastern Time.

Online registration for the Annual Meeting will begin on May 7, 2021April 27, 2023 and you should allow ample time for the online registration. Upon completing your registration, you will receive further instructions via email, including your unique link that will allow you access to the meeting. Please be sure to following the instructions you will receive once your registration is complete.

The Annual Meeting will start at 9:10:00 a.m., Eastern Time, on June 23, 2021.13, 2023. A second email containing your unique link to access the virtual Annual Meeting will be emailed to you at 8:9:00 a.m., Eastern Time, on June 23, 202113, 2023 if registration was properly submitted. You may log on to the virtual meeting starting one hour before it begins.

If you encounter any difficulties accessing the meeting during check-in or at the time of the virtual meeting, please contact technical support, whose contact information will be included in the email containing the unique link granting access to the meeting. There will be technicians standing by and ready to assist you with any technical difficulties you may have accessing the virtual meeting.

How to Vote

If you are the stockholder of record of your shares, you can vote your shares by proxy prior to the Annual Meeting or online during the Annual Meeting.

If you choose to vote by proxy prior to the Annual Meeting, you may do so by telephone, via the Internet or by mail as follows:

In order to attend the Annual Meeting online and vote online during the Annual Meeting, you must register in advance at https://www.proxydocs.com/INZY prior to the deadline of June 21, 202111, 2023 at 5:00 p.m., Eastern Time. You may vote your shares online while virtually attending the Annual Meeting by following the instructions found on your Notice of Availability, proxy card and/or voting instruction form and subsequent instructions that will be delivered to you via email following your registration. If you vote by proxy prior to the Annual Meeting and choose to attend the Annual Meeting online, there is no need to vote again during the Annual Meeting unless you wish to change your vote.

If your shares are held in street name, your bank, broker or other nominee is required to vote the shares it holds on your behalf according to your instructions. The proxy materials, as well as voting and revocation instructions, should have been forwarded to you by the bank, broker or other nominee that holds your shares. In order to vote your shares you will need to follow the instructions that your bank, broker or other nominee provides you. The voting deadlines and availability of telephone and Internet voting for beneficial owners of shares held in “street

“street name” will depend on the voting processes of the bank, broker or other nominee that holds your shares. Therefore, we urge you to carefully review and follow the voting instruction form and any other materials that you receive from that organization. If your shares are held in “street name”, you must demonstrate proof of beneficial ownership to virtually attend the Annual Meeting and must obtain a legal proxy from your bank, broker or other nominee to vote at the Annual Meeting. Only stockholders who have registered to attend the meeting by June 21, 202111, 2023 at 5:00 p.m., Eastern Time, using the process described above may vote during the meeting.

Even if you plan to attend the Annual Meeting online, we urge you to vote your shares by proxy in advance of the Annual Meeting so that if you should become unable to attend the Annual Meeting your shares will be voted as directed by you.

Can I Vote My Shares by Filling Out and Returning the Notice of Internet Availability of Proxy Materials?

No. The Notice of Availability and proxy card contain instructions on how to vote by proxy via the Internet, by telephone, by requesting and returning a paper proxy card, or by voting online while virtually attending the Annual Meeting.

How Do I Submit a Question for the Annual Meeting?

If you wish to submit a question for the Annual Meeting, you may do so during the registration process for the Annual Meeting. In addition, on the day of the Annual Meeting, beginning at 8:9:45 a.m., Eastern Time, on June 23, 2021,13, 2023, you may submit a question for the Annual Meeting by logging into the virtual meeting platform using the unique link provided to you via email one hour prior to the start of Annual Meeting and following the instructions there.

Our virtual meeting will be governed by our Rules of Conduct and Procedures which will be posted at https://www.proxydocs.com/INZY during the Annual Meeting. The Rules of Conduct and Procedures will address the ability of stockholders to ask questions during the meeting, including rules on permissible topics, and rules for

how questions and comments will be recognized and disclosed to meeting participants. We will answer appropriate questions that are pertinent to our company and the matters to be voted on by the stockholders at the Annual Meeting. Because time is limited at the Annual Meeting, we may not be able to answer all questions that are submitted. If there are any matters of individual concern to a stockholder and not of general concern to all stockholders, or if a question was not otherwise answered, such matters may be raised separately after the Annual Meeting by contacting Investor Relations at ir@inozyme.com. To promote fairness and the efficient use of our resources and to address all stockholder questions, we will limit each stockholder to two questions, which should each be succinct and should cover only one topic. Questions from multiple stockholders on the same topic or that are otherwise related may be grouped, summarized and answered together.

May I See a List of Stockholders Entitled to Vote as of the Record Date?

A list of registered stockholders as of the close of business on the record date will be available for examination by any stockholder for any purpose germane to the Annual Meeting for a period of at least 10 days prior to the Annual Meeting. If you wish to view this list, please contact our Secretary at Inozyme Pharma, Inc., 321 Summer Street, Suite 400, Boston, MA 02116, (857) 330-4340. Such list will also be available for examination by our stockholders of record during the Annual Meeting using the unique link provided via email following the completion of registration for the Annual Meeting.

Quorum

A quorum of stockholders is necessary to hold a valid meeting. Our amended and restated bylaws provide that a quorum will exist if stockholders holding a majority of the shares of stock issued and outstanding and entitled to vote at the meeting are present at the meeting in person or represented by proxy. Shares that are represented virtually during the Annual Meeting will be considered shares of common stock represented in person at the meeting for purposes of determining whether a quorum exists. If a quorum is not present, we expect to adjourn the Annual Meeting until a quorum is obtained.

Abstentions and broker non-votes“broker non-votes” count as present for establishing a quorum but will not be counted as votes cast. Broker non-votes occur when your bank, broker or other nominee submits a proxy for your shares (because the bank, broker or other nominee has received instructions from you on one or more proposals, but not all proposals, or has not received instructions from you but is entitled to vote on a particular “discretionary” matter) but does not indicate a vote for a particular proposal because the bank, broker or other nominee either does not have the authority to vote on that proposal and has not received voting instructions from you or has discretionary authority but chooses not to exercise it.

Ballot Measures Considered “Discretionary” and “Non-Discretionary”“Non-Discretionary”

If your shares are held in “street name,” your bank, broker or other nominee may under certain circumstances vote your shares even if you do not return voting instructions. Banks, brokers or other nominees are permitted to vote customers’ shares for which they have received no voting instructions on specified routine, or “discretionary,”“discretionary” matters, but they are not permitted to vote these shares on other non-routine,“non-discretionary” matters. or “non-discretionary,” matters.

The election of directors (Proposal No. 1) is considered a non-discretionary matter under applicable rules. Therefore, if your shares are held in “street name,” your bank, broker or other nominee cannot vote on this matter without voting instructions from you. The ratification of the appointment of Ernst & Young LLP as our independent registered public accounting firm for the year ending December 31, 2021 (Proposal No. 2) is considered a discretionary matter under applicable rules. Therefore, if your shares are held in “street name,” your bank, broker or other nominee may exercise discretionary authority to vote on this matter in the absence of voting instructions from you.

If you do not instruct your bank, broker or other nominee how to vote with respect to the election of directors (Proposal No. 1), your bank, broker or other nominee may not vote with respect to this proposal and your shares will be counted as “broker non-votes.” Broker non-votes are

The ratification of the appointment of Ernst & Young LLP as our independent registered public accounting firm for the year ending December 31, 2023 (Proposal No. 2) is considered a discretionary matter under applicable rules. Therefore, if your shares that are held in “street name” by aname,” we expect that your bank, broker or other nominee that indicates on its proxy card that it does not have or did notwill be able to exercise discretionary authority to vote on a particular matter.

This section provides qualitative information regarding the manner and context in which compensation is awarded to and earned by our executive officers and directors and is intended to place in perspective the data presented in the tables and narrative that follow.

Executive and Director Compensation Processes

Our executive compensation program is administered by the compensation committee of our board of directors, subject to the oversight and approval of our board of directors. Our compensation committee reviews our executive compensation practices on an annual basis and based on this review approves, or, as appropriate, makes recommendations to our board of directors for approval of, our executive compensation program.

Our director compensation program is administered by our board of directors based on recommendations by the compensation committee. We anticipate that theOur compensation committee will conduct future annualperiodically reviews ofour director compensation program and makemakes recommendations to the board of directors with respect thereto.

In designing our executive compensation program and our director compensation program, our compensation committee considers compensation data for national and regionalfrom comparable publicly traded companies in the biotechnology and the biopharmaceutical industry (based on, among other things, industry market capitalization, headcount and location) provided by our independent compensation consultant, Radford, an AON Hewitt Company.which was Aon’s Human Capital Solutions practice, a division of Aon plc (formerly Radford), until June 2022, and Alpine Rewards, following June 2022.

During 2020,2022, our compensation committee retained RadfordAon and then Alpine Rewards to advise the compensation committee on our compensation program for executive officers, which includes base salaries, annual performance-based cash bonuses, annual equity incentive awards and severance arrangements, and on the establishment of our director compensation program, which includes board and committee fee retainers and equity awards. RadfordThe compensation committee established a peer group. The compensation consultants made recommendations with respect to the amount and form of executive officer and director compensation. Although our compensation committee considers the advice and guidance of Radfordthe compensation consultants as to our executive compensation program and our director compensation program, our compensation committee ultimately makes its own decisions about these matters. In the future, we expect that our compensation committee will continue to engage independent compensation consultants to provide additional guidance on our executive compensation programs and director compensation programs and to conduct further competitive benchmarking against a peer group of publicly traded companies.

The compensation committee reviewed information regarding the independence and potential conflicts of interest of Radford,Alpine, taking into account, among other things, the factors set forth in the Nasdaq listing standards. Based on such review, the compensation committee concluded that the engagement of RadfordAlpine did not raise any conflict of interest.

Summary Compensation Table

The following table sets forth information regarding compensation awarded to, earned by or paid to each of our named executive officers for the years ended December 31, 20202022 and 2019.2021.

(1) The amounts reported in the “Option Awards” column reflect the grant date fair value of stock options awarded during the year computed in accordance with the provisions of Financial Accounting Standard Board, or FASB, Accounting Standards Codification, or ASC, Topic 718, using a Black Scholes option-pricing model. See Note 9 to our consolidated financial statements appearing in our Annual

Narrative to Summary Compensation Table

Base Compensation. We use base compensation or salaries to recognize the experience, skills, knowledge and responsibilities required of our executive officers. None of our executive officers is currently party to an employment agreement or other agreement or arrangement that provides for automatic or scheduled increases in base compensation or salary.

In 2020,Effective March 1, 2022, our compensation committee increased Mr. Bolte earnedBolte’s annual base compensation of $440,099salary from $540,750 to $559,676 and increased Mr. Bjarke and Dr. Huertas earnedBjarke’s annual base salary of $389,782 and $397,843, respectively.

from $443,106 to $458,615. In March 2020,2022, our board of directors set Mr. Bolte’s 2020 monthly base compensation at $32,445 for an aggregate annual amount of $389,340. In March 2020, our board of directors set Mr. Bjarke’s and Dr. Huertas’ 2020 annual baseSubramanian’s salary at $360,706 and $378,750, respectively. $430,000 in connection with the commencement of his employment as our chief financial officer.

Effective upon the effectiveness of our registration statement for our initial public offering in July 2020, the annual base salary of Mr. Bolte, Mr. Bjarke and Dr. Huertas was increased to $525,000, $430,200 and $423,200, respectively.

In March 2021,1, 2023, our compensation committee set Mr. Bolte’s and Mr. Bjarke’s 2021 annual baseSubramanian’s salary at $540,750 and $443,106, respectively. Dr. Huertas resigned as our chief medical officer in January 2021.$447,200.

Annual Bonus. Our From time to time, our board of directors may, in its discretion, awardor our compensation committee has approved annual cash bonuses to our executive officers from timewith respect to time.their prior year performance. Our executive officers are eligible for annual performance-based bonuses up to a specified percentage of their base compensation or salary, subject to approval by our board of directors or the compensation committee. Performance-based bonuses, which are calculated as a percentage of base compensation or salary, are designed to motivate our executive officers to achieve annual goals based on our strategic, financial and operating performance objectives. From time to time, our board of directors has approved annual cash bonuses to our executive officers with respect to their prior year performance.

In March 2020, our board of directors set the 2020The 2022 target bonus amounts, expressed as a percentage of 2020 base compensation or salary, at 50% for Mr. Bolte and 35% for each of Mr. Bjarke and Dr. Huertas. Effective upon the effectiveness of our registration statement for our initial public offering in July 2020, the target bonus amounts, expressed as a percentage of2022 base salary, were increased to 55% for Mr. Bolte and 40% for each of Mr. Bjarke and Dr. Huertas.Mr. Subramanian.

For 2020,2022, bonuses were based on attaining corporate goalsobjectives relating to regulatory and clinical progress and development for INZ-701, advancing early stage development programs, financing, manufacturing activities, and advancing our company into clinical development.financing. With respect to 20202022 performance, our compensation committee reviewed performance against the 20202022 corporate goals and determined that the corporate goals were achieved at 120%.100% for the executive officers. The compensation committee approved 20202022 cash bonuses of $290,466 and $187,095$306,087 for Mr. Bolte and $189,200 for Mr. Bjarke, respectively,Subramanian, which amounts represented 120%approximately 100% and 110% of each such officer’s target bonus amount. In accordance with Dr. Huertas’ separation agreement, Dr. Huertas receivedamounts, respectively. Mr. Bjarke was not entitled to receive a 2020 cash bonus of $159,137, which amount represented 100% of his target bonus amount. For a description of Dr. Huertas’ separation agreement, see “—Separation Agreement with Pedro Huertas” below.for 2022 performance.

Equity Incentives. Although we do not have a formal policy with respect to the grant of equity incentive awards to our executive officers, or any formal equity ownership guidelines applicable to them, we believe that equity grants provide our executive officers with a strong link to our long-term performance, create an ownership culture and help to align the interests of our executive officers and our stockholders. In addition, we believe that equity grants with a time-based vesting feature promote executive officer retention, because this feature incentivizes our executive officers to remain in our employment during the vesting period. Accordingly, our board of directors or our compensation committee periodically reviews the equity incentive compensation of our executive officers and from time to time may grant equity incentive awards to them in the form of stock options.

In April 2020,February 2022, we granted options to purchase 159,187, 51,105275,000 and 36,074115,000 shares of our common stock to Mr. Bolte, Mr. Bjarke and Mr. Huertas, respectively, at an exercise price per share of $2.77. These options were merit-based awards, and such options vest in equal monthly installments over a term of four years fromunder our 2020 Stock Incentive Plan, or the vesting commencement date of April 23, 2020 with vesting contingent upon the acceptance by the U.S. Food and Drug Administration of our investigational new drug application for INZ-701 on or prior to April 23, 2021, subject to continued service. The performance-based vesting criteria was satisfied in January 2021.

We also granted options to purchase 354,494, 32,905 and 43,951 shares of our common stock to Mr. Bolte, Mr. Bjarke and Dr. Huertas, respectively, effective upon the effectiveness of our registration statement for our initial public offering in July 2020, at an exercise price per share of $16.00. The grants to Mr. Bolte

consisted of an option to purchase 287,706 shares of our common stock, which vests in equal monthly installments over a term of four years from July 23, 2020, and an option to purchase 66,788 shares of our common stock, which vests in equal monthly installments over a term of four years from the vesting commencement date of July 23, 2020, with vesting contingent upon the acceptance by the U.S. Food and Drug Administration of our investigational new drug application for INZ-701 on or prior to July 23, 2021. The performance-based vesting criteria was satisfied in January 2021. The grants made to Mr. Bjarke and Dr. Huertas vest in equal monthly installments over a term of four years from the vesting commencement date of July 23, 2020.

In March 2021, we granted options to purchase 117,000 and 51,000 shares of our common stockPlan, to Mr. Bolte and Mr. Bjarke, respectively, at an exercise price per share of $19.78.$5.78. Such options vest in equal monthly installments over a term of four years from the vesting commencement date of February 24, 2022. In March 4, 2021.2022, we granted an option to purchase 180,000 shares of our common stock under the 2020 Plan to Mr. Subramanian, at an exercise price per share of $3.96. Such option vests as to 25% of the shares underlying the option on March 21, 2023 and as to 2.0833% of the shares subject to the option at the end of each successive one-month period following March 21, 2023 until March 21, 2026.

In March 2023, we granted an option to purchase 135,000 shares of our common stock under the 2020 Plan to Mr. Subramanian, at an exercise price per share of $3.30. Such option vests in equal monthly installments over a term of four years from the vesting commencement date of March 23, 2023.

Prior to our initial public offering, our executive officers were eligible to participate in our Amended and Restated 2017 Equity Incentive Plan, as amended to date, or the 2017 Plan, and all options were granted pursuant to the 2017 Plan, other than the stock option grants that were effective upon the effectiveness of the registration statement for our initial public offering in July 2020, which were granted pursuant to our 2020 Stock Incentive Plan, or the 2020 Plan. Following the closing of our initial public offering, our employees and executive officers became eligible to receive stock options and other stock-based awards pursuant to our 2020 Plan. For a description of our 2017 Plan and our 2020 Plan, see “—Stock Option and Other Compensation Plans” below.

We use stock options to compensate our executive officers in the form of initial grants in connection with the commencement of employment and also at various times, often but not necessarily annually, if we or they have performed as expected or better than expected. None of our executive officers is currently party to an employment agreement that provides for the automatic award of stock options. We have granted option awards to our executive officers with time-based vesting and performance-based vesting. The option awards that we have granted to our executive officers in connection with commencement of employment typically become exercisable as to 25% of the shares underlying the option on the first anniversary of the vesting commencement date and as to an additional 2.0833% of the original number of shares underlying the option monthly thereafter. The option awards that we have granted to our executive officers at times other than in connection with employment typically become exercisable in equal monthly installments over a term of four years from the applicable vesting commencement date. Vesting rights cease upon termination of employmentservice and exercise rights for previously vested stock options cease shortly after termination, though exercisability is extended in the case of death or disability. Prior to the exercise of an option, the holder has no rights as a stockholder with respect to the shares subject to such option, including no voting rights and no right to receive dividends or dividend equivalents.

We have historically granted stock options with exercise prices that are equal to the fair market value of our common stock on the date of grant as determined by our board of directors, based on a number of objective and subjective factors. The exercise price of all stock options granted after the closing of our initial public offering has been and going forward will beis equal to the fair market value of shares of our common stock on the date of grant, which will beis determined by reference to the closing market price of our common stock on the Nasdaq Global Select Market on the date of grant.

Outstanding Equity Awards at December 31, 20202022

The following table sets forth information regarding all outstanding stock options and shares of restricted stock held by each of our named executive officers as of December 31, 2020.2022.

(2) This option vests over four years, in equal monthly installments through June 20, 2023, subject to continued service.

(3) This option vests over four years, in equal monthly installments through April 23, 2024, subject to continued service.

(4) This option vests over four years, in equal monthly installments through July 23, 2024, subject to continued service.

(5) This option vests over four years, in equal monthly installments through March 4, 2025, subject to continued service.

(6) This option vests over four years, in equal monthly installments through February 24, 2026, subject to continued service.

(7) This option vests over four years, with 25% of the shares vested on March 21, 2023 and 2.0833% of the original number of shares vesting thereafter in equal monthly installments through March 21, 2026, subject to continued service.

Employment and Other Agreements

We have entered into written employment agreements with each of our executive officers. These agreements set forth the terms of the executive officer’s compensation, including base salary, annual discretionary bonus eligibility and severance benefits, among other matters. The employment agreements with Mr. Bolte, Mr. Bjarke and Mr. Subramanian, our named executive officers, and Dr. Treco, our chief executive officer as of April 1, 2023, are summarized below. In addition, we have entered into separation and consulting agreements with Mr. Bolte and Mr. Bjarke in connection with their respective resignations, the terms of which are also summarized below.

Employment Agreement with Axel Bolte

In March 2021, Inozyme Pharma Switzerland GmbH, or the GmbH, our wholly owned subsidiary, entered into an employment contract with Mr. Bolte, effective April 1, 2021, in connection with the transfer of Mr. Bolte’s employment to the GmbH, which we refer to as the Bolte employment contract. Under the Bolte employment contract, Mr. Bolte servesserved as the chief executive officer to the group consisting of us and our subsidiaries, or the Group. The Bolte employment contract supersedessuperseded and replacesreplaced an employment agreement we entered into with Mr. Bolte in July 2020 in connection with his employment as our chief executive officer, which employment agreement superseded a consulting agreement for Mr. Bolte’s services that we previously entered into in June 2017, as it was subsequently amended.

Under the Bolte employment contract, Mr. Bolte’s employment can be terminated by Mr. Bolte or by the GmbH upon one month’s notice of termination, except under certain limited circumstances whereby the GmbH can terminate Mr. Bolte immediately under Swiss law. Pursuant to the Bolte employment contract, Mr. Bolte’s annualized base salary for 2021 is $540,750, and he is eligible to receive an annual discretionary bonus of up to 55% of his gross base salary for the applicable calendar year. For a period of up to 24 months following July 23, 2020, Mr. Bolte will bewas reimbursed for his travel expenses between his home and our Boston area headquarters.

Under the Bolte employment contract, Mr. Bolte iswas entitled, subject to his execution and nonrevocation of a release of claims in favor of the GmbH and his continued compliance with certain restrictive covenants, in the event of the termination of his employment by the GmbH without cause or by him for good reason, each as defined in the Bolte employment contract, to (1) continued payment of his then-current annual base salary for a period of 12 months following the date his release of claims becomes effective, (2) continued payment by the GmbH of its share of the COBRA premiums for health benefit coverage for a period of up to 12 months following the date that his employment is terminated, and (3) payment of a pro-rated portion of his annual target discretionary bonus that he would otherwise have received based on individual and Group performance in a lump sum on the date the first installment of severance pay is paid.

In the event that Mr. Bolte’s employment is terminated by the GmbH without cause or by Mr. Bolte with good reason during the 60-day period prior to a change in control, as defined in the Bolte employment contract, or during the 12-month period following a change in control, Mr. Bolte will be entitled, subject to his execution and nonrevocation of a release of claims in favor of the GmbH and his continued compliance with certain restrictive covenants, to (1) continued payment of his then-current annual base salary for a period of 18 months following the date his release of claims becomes effective, (2) continued payment by the GmbH of its share of the COBRA premiums for health benefit coverage for a period of up to 18 months following the date that his employment is terminated, and (3) payment of 150% of his annual target discretionary bonus amount for the year in which the termination occurs in a lump sum on the date the first installment of severance pay is paid. In addition, Mr. Bolte will be entitled to full acceleration of vesting of all outstanding and unvested stock options and other equity awards that vest solely based on continued service. However, if Mr. Bolte’s termination date is within 60 days prior to the closing of a change in control, then such accelerated vesting will not occur unless and until the closing of a change in control within 60 days of his termination date. Under the Bolte employment contract, if payments and benefits payable to Mr. Bolte that are contingent on a change in ownership or control, as defined the Bolte employment contract, are subject to Section 4999 of the Internal Revenue Code of 1986, then such payments and benefits will either be paid in full or be reduced so that the Section 4999 excise tax does not apply, whichever results in the better after-tax result for Mr. Bolte.

The aggregate amount of severance payments payable as described above will be reducedwere subject to reduction by any amount Mr. Bolte may behave been entitled to under statutory Swiss employment legal provisions applicable in case of the termination of the Bolte employment contract, such as, but not limited to, gross salary (including bonus), any compensation for unfair dismissal or dismissal without notice under statutory Swiss law or daily benefits paid by a social security fund.

Separation Agreement and Consulting Agreement with Axel Bolte

On March 21, 2023, we entered into a transition and separation letter agreement with Mr. Bolte, or the Bolte Separation Agreement. The Bolte Separation Agreement provides for (i) Mr. Bolte’s resignation from his position as our president and chief executive officer and as chief executive officer of the GmbH, in each case effective as of April 1, 2023, and (ii) Mr. Bolte’s separation from employment with the GmbH as of April 30, 2023, or the Separation Date. Pursuant to the Bolte Separation Agreement, during the time between April 1, 2023 and the Separation Date, Mr. Bolte will continue to receive his current base salary, as adjusted to reflect net pay of $25,000 per month. Pursuant to the Bolte Separation Agreement, as of the Separation Date, Mr. Bolte is entitled, subject to his execution and nonrevocation of a release of claims in favor of the GmbH and its affiliates, including the company, and his continued compliance with certain restrictive covenants, to (i) continued payment of his current base salary for a period of 12 months following the date his release of claims becomes effective, for an aggregate of $558,558, (ii) continued payment by the GmbH of its share of the COBRA premiums for health benefit coverage for a period of up to 12 months following the date that his employment is terminated, and (iii) payment of a pro-rated portion of his annual target discretionary bonus that he would otherwise have received based on individual and company performance in a lump sum on the date the first installment of severance pay is paid. The Bolte Separation Agreement also provides for, among other things, non-disclosure obligations applicable to Mr. Bolte and mutual non-disparagement obligations. We have also agreed to reimburse Mr. Bolte for reasonable attorneys’ fees in connection with the negotiation of the Bolte Separation Agreement in an amount not to exceed $25,000.

In connection with his resignation, we and Mr. Bolte intend to enter into a Consulting Agreement, or the Bolte Consulting Agreement, to be effective as of May 1, 2023, or the Consulting Start Date, pursuant to which Mr. Bolte will serve as a senior advisor and assist with the transition of his duties and provide other strategic and operational consulting and advisory services, as requested from time to time by us. Mr. Bolte will be compensated at a rate of $25,000 per month for his services under the Bolte Consulting Agreement for the first three months of the term of the Bolte Consulting Agreement, or the Initial Period. Following the Initial Period, Mr. Bolte will be compensated at a specified hourly rate for services under the Bolte Consulting Agreement. In addition, in respect of his services as a consultant, we granted, effective as of the Consulting Start Date, Mr. Bolte an option to purchase 100,000 shares of our common stock, or the Bolte Option, under the 2020 Plan. The Bolte Option will vest and become exercisable as to 4.1667% of the shares subject to the Bolte Option at the end of each successive one-month period following the Consulting Start Date until the second anniversary of the Consulting Start Date, subject to Mr. Bolte’s continued provision of services to us. The term of the Bolte Consulting Agreement will continue until May 1, 2025 (the period from the Consulting Start Date to May 1, 2025, is the referred to herein as the Bolte Consultation Period). We and Mr. Bolte will be able to terminate the Bolte Consulting Agreement on 30 days prior written notice, but in the case of a termination by us, with such termination being effective no earlier than the day following the end of the Initial Period.

In the event (1) Mr. Bolte terminates the Bolte Consulting Agreement as a result of our material breach of the Bolte Consulting Agreement or the Bolte Separation Agreement, (2) we terminate the Bolte Consulting Agreement without cause upon 30 days prior written notice or (3) Mr. Bolte dies or becomes disabled during the Bolte Consultation Period, (A) Mr. Bolte will be entitled to the accelerated vesting of (i) any unvested portion of the Bolte Option and (ii) any other stock options granted by us to Mr. Bolte that remain outstanding at the date of such termination but solely with respect to the portion of such stock options that otherwise would have vested during the Bolte Consultation Period, and (B) any stock options granted by us to Mr. Bolte that are vested and outstanding as of the date of such termination (taking into account clause (A) of this sentence) will remain exercisable until the earlier of (x) the later of May 1, 2026 or Mr. Bolte ceasing to serve on the board of directors and (y) the original expiration date of such options.

Employment Agreement with Henric Bjarke

In connection with our initial hiring of Mr. Bjarke as our senior vice president and chief operating officer, we entered into an agreement with him in June 2017. We entered into an amended and restated agreement with Mr. Bjarke in July 2020, which we refer to as the Bjarke employment agreement. Under the Bjarke employment agreement, Mr. Bjarke iswas an at-will employee, and his employment with us can be terminated by Mr. Bjarke or us at any time and for any reason. Pursuant to the Bjarke employment agreement, Mr. Bjarke’s annualized base salary was $430,200 for 2020, and he is eligible to receive an annual discretionary bonus of up to 40% of his gross base salary for the applicable calendar year. Mr. Bjarke’s base salary is reviewed by our compensation committee and the board of directors on an annual or more frequent basis and is subject to change in the discretion of our board of directors or compensation committee. Mr. Bjarke’s base salary for 2021 is $443,106. employee. For a period of up to 24 months following July 23, 2020, we will reimbursereimbursed Mr. Bjarke for his travel expenses between his home and our Boston area headquarters on a grossed-up basis.

Under the Bjarke employment agreement, and in connection with our initial public offering, we granted

Mr. Bjarke an option to purchase 32,905 shares of our common stock at a price per share equal to $16.00.

Under the Bjarke employment agreement, Mr. Bjarke iswas entitled, subject to his execution and nonrevocation of a release of claims in our favor and his continued compliance with certain restrictive covenants, in the event of the termination of his employment by us without cause or by him for good reason, each as defined in the Bjarke employment agreement, to (1) continued payment of his then-current annual base salary for a period of nine months following the date his release of claims becomes effective, and (2) continued payment by us of our share of the COBRA premiums for health benefit coverage for a period of up to nine months following the date that his employment with us is terminated.

Separation Agreement and Consulting Agreement with Henric Bjarke

On December 7, 2022, we entered into an executive transition, separation and release of claims agreement, or the Bjarke Separation Agreement, with Mr. Bjarke providing for his resignation as senior vice president and chief operating officer effective December 31, 2022. On December 7, 2022, we also entered into a consulting agreement, or the Bjarke Consulting Agreement, with Mr. Bjarke pursuant to which he has agreed to provide consulting and advisory services related to our precommercial and commercial preparedness and business development activities from January 1, 2023 to June 30, 2023, unless earlier terminated, the Bjarke Consultation Period.

Pursuant to the Bjarke Separation Agreement, Mr. Bjarke is entitled to receive continued payment of his 2022 annual base salary for a period of nine months, for an aggregate of $343,961, following the end of the Bjarke Consultation Period, subject to Mr. Bjarke’s execution and nonrevocation of a release of claims in our favor and compliance with the Bjarke Separation Agreement, the release and applicable restrictive covenants. In addition, subject to eligibility, the Bjarke Separation Agreement provides for continued payment by us of our share of COBRA premiums for Mr. Bjarke’s health benefit coverage for a period of up to nine months following December 31, 2022. The Bjarke Separation Agreement also provides for, among other things, nondisclosure obligations applicable to Mr. Bjarke and mutual non-disparagement obligations.

In consideration for services under the Bjarke Consulting Agreement, we have agreed to pay Mr. Bjarke consulting fees at specified hourly rates. For so long as Mr. Bjarke is providing services to us during the Bjarke Consultation Period, Mr. Bjarke’s equity awards that vest solely based on the passage of time will continue to vest and remain exercisable in accordance with the applicable equity plans and award agreements. In addition, in accordance with the Bjarke Separation Agreement, (1) effective as of June 30, 2023, the vesting of Mr. Bjarke’s option to purchase 115,000 shares of our common stock granted on February 24, 2022 will accelerate with respect to 50,000 unvested shares, or the Accelerated Option, and (2) any vested options held by Mr. Bjarke that remain outstanding at the end of the Bjarke Consultation Period (including the Accelerated Option) will remain exercisable until the earlier of one year following the end of the Bjarke Consultation Period or the original expiration date of such option, or the Extended Exercise Period, in each case, provided that Mr. Bjarke complies with his obligations under the Bjarke Separation Agreement and the Bjarke Consulting Agreement. If the Bjarke Consulting Agreement is terminated by us other than for material breach by Mr. Bjarke or by Mr. Bjarke for material breach by us, then Mr. Bjarke will be entitled to (1) the Accelerated Option, on the terms and subject to certain conditions set forth in Bjarke Separation Agreement, (2) accelerated vesting of each outstanding stock option held by Mr. Bjarke with respect to the portion of such options that would have vested had Mr. Bjarke continued to provide services under the Bjarke Consulting Agreement through June 30, 2023 and (3) the Extended Exercise Period for vested stock options that are outstanding on the date of termination, on the terms and subject to certain conditions set forth in the Bjarke Separation Agreement.

Employment Agreement with Sanjay S. Subramanian

On March 2, 2022, we entered into an employment agreement with Mr. Subramanian, which we refer to as the Subramanian employment agreement. Under the Subramanian employment agreement, Mr. Subramanian is an at-will employee, and his employment with us can be terminated by Mr. Subramanian or us at any time and for any reason. Mr. Subramanian’s base salary is reviewed by our compensation committee and the board of directors on an annual or more frequent basis and is subject to change in the discretion of our board of directors or compensation committee. Mr. Subramanian’s annualized base salary for 2022 was $430,000. He received a cash signing bonus of $105,000, which was paid in two installments: $55,000 in connection with his commencement of employment on March 21, 2022, or the Subramanian Effective Date, and $50,000 six months thereafter.

Following the end of each calendar year, Mr. Subramanian will be eligible to receive a discretionary retention and performance bonus with a target of 40% of his then gross base pay actually earned during the applicable calendar year based upon the board’s assessment of his performance and our performance. We granted Mr. Subramanian an option to purchase 180,000 shares of our common stock under the 2020

Plan, effective as of the Subramanian Effective Date. The option vests and becomes exercisable as to 25% of the shares underlying the option on the first anniversary of the Subramanian Effective Date and as to 2.0833% of the shares subject to the option at the end of each successive one-month period following the first anniversary of the Subramanian Effective Date until the fourth anniversary thereof.

Under the Subramanian employment agreement, Mr. Subramanian is entitled, subject to his execution and nonrevocation of a release of claims in our favor and his continued compliance with certain restrictive covenants, in the event of the termination of his employment by us without cause or by him for good reason, and such termination does not take place during the 12-month period following a change in control, each as defined in the Subramanian employment agreement, to (1) continued payment of his then-current annual base salary for a period of nine months following the date his release of claims becomes effective, (2) continued payment by us of its share of the COBRA premiums for health benefit coverage for a period of up to nine months following the date that his employment with us is terminated, and (3) in the event of termination between January 1 and the date annual discretionary bonuses are paid, payment of his annual target discretionary bonus amount for the year prior to termination in a lump sum on the date the first installment of severance pay is paid.

In the event that Mr. Bjarke’sSubramanian’s employment is terminated by us without cause or by Mr. Bjarkehim with good reason during the 12-month period following a change in control, as defined in the BjarkeSubramanian employment agreement, Mr. BjarkeSubramanian will be entitled, subject to his execution and nonrevocation of a release of claims in our favor and his continued compliance with certain restrictive covenants, to (1) continued payment of his then-current annual base salary for a period of 12 months following the date his release of claims becomes effective, (2) continued payment by us of ourits share of the COBRA premiums for health benefit coverage for a period of up to 12 months following the date that his employment with us is terminated, and (3) payment of 100% of his annual target discretionary bonus amount for the year in which the termination occurs in a lump sum on the date the first installment of severance pay is paid. In addition, Mr. BjarkeSubramanian will be entitled to full acceleration of vesting of all outstanding and unvested stock options and other equity awards that vest solely based on continued service. Under the BjarkeSubramanian employment agreement, if payments and benefits payable to Mr. BjarkeSubramanian that are contingent on a change in ownership or control, as defined the BjarkeSubramanian employment agreement, are subject to Section 4999 of the Internal Revenue Code of 1986, then such payments and benefits will either be paid in full or be reduced so that the Section 4999 excise tax does not apply, whichever results in the better after-tax result for Mr. Bjarke.Subramanian.

SeparationEmployment Agreement with Pedro HuertasDouglas Treco

In January 2021,On March 21, 2023, we entered into a separationan employment agreement with Dr. HuertasTreco, which we refer to as the Treco employment agreement. Under the Treco employment agreement, Dr. Treco is an at-will employee, and his employment with us can be terminated by Dr. Treco or us at any time and for any reason. Dr. Treco’s base salary will be reviewed by our compensation committee and the board of directors on an annual or more frequent basis and is subject to change in connectionthe discretion of our board of directors or compensation committee. Dr. Treco’s annualized base salary for 2023 is $500,000 and he received a signing bonus of $7,500.

Following the end of each calendar year, Dr. Treco will be eligible to receive a discretionary retention and performance bonus with a target of 55% of his resignationthen gross base pay actually earned during the applicable calendar year based upon the board’s assessment of his performance and our performance. We granted Dr. Treco an option to purchase 800,000 shares of our common stock under the 2020 Plan, effective as of April 1, 2023, or the Treco Effective Date. The option vests and becomes exercisable as to 2.0833% of the shares subject to the option at the end of each successive one-month period following the Treco Effective Date until the fourth anniversary of the Treco Effective Date. We also granted Dr. Treco a restricted stock unit award with respect to 100,000 shares of our senior vice presidentcommon stock, or the RSU, under the 2020 Plan, effective as of the Treco Effective Date. The RSU vests and chief medical officer. In consideration forbecomes exercisable as to 25% of the shares underlying the RSU on each anniversary of the Treco Effective Date until the fourth anniversary of the Treco Effective Date.

Under the Treco employment agreement, Dr. Huertas’Treco is entitled, subject to his execution and nonrevocation of a release of claims in our favor we agreedand his continued compliance with certain restrictive covenants, in the event of the termination of his employment by us without cause or by him for good reason, and such termination does not take place during the 60-day period prior to (1) makea change in control or the 12-month period following a change in control, each as defined in the Treco employment agreement, to (i) continued paymentspayment of Dr. Huertas’ 2020his then-current annual base salary for a period of nine12 months following the date his release of claims becamebecomes effective, (2) make(ii) continued paymentspayment by us of our share of the COBRA premiums for health benefit coverage for a period of up to nine12 months following the date that his

departure employment with us is terminated, and (iii) payment, in a lump sum on the date the first installment of severance pay 100%is paid, of a pro-rata portion of his 2020annual discretionary bonus, if any, that the board determines he would have received during the applicable calendar year until his date of termination. In addition, the option and the RSU will vest with respect to the number of shares subject to such equity awards that would have vested within the one-year period following Dr. Treco’s termination had he remained employed with us during such period.

In the event that Dr. Treco’s employment is terminated by us without cause or by him with good reason during the 60-day period prior to a change in control or the 12-month period following a change in control, as defined in the Treco employment agreement, Dr. Treco will be entitled, subject to his execution and nonrevocation of a release of claims in our favor and his continued compliance with certain restrictive covenants, to (i) continued payment of his then-current annual base salary for a period of 18 months following the date his release of claims becomes effective, (ii) continued payment by us of our share of the COBRA premiums for health benefit coverage for a period of up to 18 months following the date that his employment with us is terminated, and (iii) payment of 150% of his annual target discretionary bonus

amount for the year in an amountwhich the termination occurs in a lump sum on the date the first installment of $159,137. Followingseverance pay is paid. In addition, Dr. Huertas’ departure, he exercisedTreco will be entitled to full acceleration of vesting of all outstanding and unvested stock options to purchase 65,781 shares of common stock. All unvestedand other equity awards terminated and were no longer exercisable.that vest solely based on continued service.

Employee Proprietary Rights, Non-Disclosure, Developments, Non-Competition, and Non-Solicitation Agreements Agreements

Each of our executive officers has entered into a standard form of agreement with respect to proprietary and confidential information, developments, non-competition, and non-solicitation. Under this agreement, each executive officer has agreed to protect our confidential and proprietary information during and after the executive officer’s employment with us, not to compete with us during his or her employment and for a period generally lasting for one year after the termination of his or her employment, and not to solicit our employees, consultants, clients or customers during his employment and for a period generally lasting for one year after the termination of his employment. In addition, under this agreement, each executive officer has agreed that we own all developments and inventions that are developed by such executive officer within the scope of and during the period of his employment with us that are related to our business or research and development conducted or planned to be conducted by us at the time such development is created. Each executive officer also agreed to provide us with a non-exclusive, royalty-free, perpetual license to use any prior inventions that such executive officer incorporates into inventions assigned to us under this agreement.

401(k) Plan

We maintain a defined contribution employee retirement plan for our employees, including our executive officers. The plan is intended to qualify as a tax-qualified 401(k) plan so that contributions to the 401(k) plan, and income earned on such contributions, are not taxable to participants until withdrawn or distributed from the 401(k) plan (except in the case of contributions under the 401(k) plan designated as Roth contributions). Under the 401(k) plan, each employee is fully vested in his or her deferred salary contributions and our discretionary match. Employee contributions are held and invested by the plan’s trustee as directed by participants. The 401(k) plan provides us with the discretion to match employee contributions. As of December 31, 2020, we had not provided any employer matching contributions. Effective January 1, 2021, we implemented a matching policy under which we match 50% of an employee’s contributions to the 401(k) plan, up to a maximum of 6% of the employee’s base salary and bonus paid during the year.

Stock Option and Other Compensation Plans

The threefour equity incentive plans described in this section are our 2017 Plan, our 2020 Plan, and our 2020 Employee Stock Purchase Plan, or 2020 ESPP.ESPP, and our 2023 Inducement Stock Incentive Plan. Prior to our initial public offering, we granted awards to eligible participants under our 2017 Plan. Following the closing of our initial public offering, we have granted awards to eligible participants under the 2020 Plan.

Securities Authorized for Issuance Under Equity Compensation Plans

Equity Compensation Plan Information

The following table contains information about our 2017 Plan, our 2020 Plan and our 2020 ESPP as of December 31, 2020.2022.

Director Compensation

The table below shows all compensation awarded to, earned by In addition, our insider trading policy prohibits such persons from purchasing our securities on margin, borrowing against our securities held in a margin account, or paid to eachpledging our securities as collateral for a loan, with an exception in extraordinary situations for pledges of our non-employee directors duringsecurities as collateral for a loan (other than a margin loan) only after certain prerequisites are met and only with the year ended December 31, 2020.

Mr. Bolte, onepreapproval of our chief financial officer or general counsel and, in the case of directors who also serves as our president and chief executive officer, does not receive any additional compensation for his service as a director. Mr. Bolte is one of our named executive officers, and, accordingly, the compensation that we pay to Mr. Bolte is discussed above under “—Summaryaudit committee.

Director Compensation Table” and “—Narrative to Summary Compensation Table.”

Prior to our initial public offering, we did not have a formal non-employee director compensation policy.program. Our board of directors approved a director compensation program that became effective in July 2020 upon the closing of our initial public offering. Under this director compensation program, we pay our non-employee directors a cash retainer for service on the board of directors and for service on each committee on which the director is a member. The chairman of the board and of each committee receive additional retainers 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 board

of directors or on such committee. No fee was payable in respect of any period prior to the completion of our initial public offering and the first payment under the director compensation program after our initial public offering was prorated. The fees paid to non-employee directors for service on the board of directors and for service on each committee of the board of directors on which the director is a member are as follows:

We also reimburse our non-employee directors for reasonable travel and other expenses incurred in connection with attending meetings of our board of directors and any committee of our board of directors on which he or she serves.

In addition, under our director compensation program, each non-employee director was entitled to receive, upon his or her initial election or appointment to our board of directors, an option to purchase 18,734 shares of our common stock under the 2020 Plan. Effective February 2023, each non-employee director will receive, upon his or her initial election or appointment to our board of directors, an option to purchase 18,73432,000 shares of our common stock under the 2020 Plan. Each of these options will vest as to 2.7778% of the shares of our common stock underlying such option at the end of each successive one-month period following the date of grant until the third anniversary of the date of grant, subject to the non-employee director’s continued service as a director. Further,On the date of the first board meeting held after each annual meeting of stockholders, each non-employee director that had served on our board of directors for at least six months received, under the 2020 Plan, an option to purchase 9,367 shares of our common stock under the 2020 Plan. Effective February 2023, on the date of the first board meeting held after each annual meeting of stockholders, each non-employee director that has served on our board of directors for at least six months will receive, under the 2020 Plan, an option to purchase 9,36716,000 shares of our common stock under the 2020 Plan. Each of these options will vest with respect to all of the shares underlying the option on the first anniversary of the date of grant or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to the non-employee director’s continued service as a director. All options issued to our non-employee directors under our director compensation program will be issued at exercise prices equal to the fair market value of our common stock on the date of grant and will become exercisable in full upon specified change in control events.

(1) The amounts reported in the “Option Awards” column reflect the aggregate grant date fair value of stock options awarded during the year computed in accordance with the provisions of ASC 718, using a Black-Scholes option-pricing model. The amounts reported reflect stock options to purchase 9,367 shares of our common stock granted to each non-employee director immediately following the 2022 annual meeting of stockholders. See Note 9 to our consolidated financial statements appearing in our Annual Report on Form 10-K filed with the SEC on March 22, 2023 regarding assumptions underlying the valuation of option awards. This amount reflects the accounting cost for this stock option and does not reflect the actual economic value that may be realized by the director upon the vesting of the stock option, the exercise of the stock option or the sale of the common stock underlying such stock option.

(2) As of December 31, 2022, the aggregate number of shares of our common stock subject to outstanding option awards for each non-employee director was as follows: Dr. Bhagat, 28,101 shares; Mr. Diaz, 28,101 shares; Dr. Edwards, 28,101 shares; Dr. Hopfner, 28,101 shares; Mr. Mathers, 28,101 shares; Ms. Sullivan, 56,469 shares; and Dr. Treco, 115,080 shares.

(3) Following Dr. Treco’s appointment as our chief executive officer effective as of April 1, 2023, he is no longer compensated for his service as a director under our non-employee director compensation program.

Mr. Bolte, one of our directors who previously served as our president and chief executive officer until his retirement and resignation on April 1, 2023, did not receive any additional compensation for his service as a director during his tenure as our president and chief executive officer. Effective May 1, 2023, Mr. Bolte will be compensated for his service as a director under our non-employee director compensation program. Mr. Bolte is one of our named executive officers for the year ended December 31, 2022 and, accordingly, the compensation that we paid to Mr. Bolte in his role as our president and chief executive officer is discussed above under “—Summary Compensation Table” and “—Narrative to Summary Compensation Table.”

TRANSACTIONS WITH RELATED PERSONS

The following is a description of transactions since January 1, 20192021 to which we have been a party, and in which any of our directors, executive officers and holders of more than 5% of our voting securities and affiliates of our directors, executive officers and holders of more than 5% of our voting securities, had or will have a direct or indirect material interest. We believe that all of the transactions described below were made on terms no less favorable to us than could have been obtained from unaffiliated third parties.

Participation in Initial PublicUnderwritten Offering

On July 28, 2020,April 19, 2022, we closed our initial publican underwritten offering in which we issued and sold an aggregate of 7,000,00016,276,987 shares of our common stock at a price to the public of $16.00 per share of $3.69 and pre-funded warrants to purchase 3,523,013 shares of common stock at a price per warrant of $3.6899, before expenses and underwriting discounts and commissions. On July 30, 2020, we issuedWe received aggregate net proceeds of approximately $68.3 million, after deducting expenses and sold an additional 1,050,000 sharesunderwriting discounts and commissions. Certain of our common stock on the same terms upon the exercise in full by the underwriters of their option to purchase additional shares. Certainexecutive officers and holders of more than 5% of our voting securities at the time of our initial publicunderwritten offering and their affiliates purchased an aggregate of 2,475,00012,849,887 shares of our common stock in the initial public offering.offering and pre-funded warrants to purchase 3,523,013 shares of our common stock. Each of those purchases was made through the underwriters at the initial publicsame offering price.price as other investors. The following table sets forth the number of shares of our common stock purchased by such executive officers, then holders of more than 5% of our voting securities and their affiliates and the aggregate purchase price paid for such shares.

Alexion Intellectual Property Asset Acquisition

In July 2020, we entered into an intellectual property asset purchase agreement with Alexion Pharmaceuticals, Inc., or Alexion, pursuant to which Alexion sold(1) See the “Principal Stockholders” section for additional information about securities held by certain of these entities and assigned to us Alexion’s right, titleexecutive officers.

(2) These pre-funded warrants were exercised by means of a cashless exercise in September 2022 and interest inFebruary 2023 and to specified patent rights and other specified assets solely related to ENPP1. We issued 8,294,360 shares of our Series A-2 Convertible Preferred Stock to Alexion in consideration for the sale and assignment to us of such assets, resulting in Alexion becoming a holder of more than 5% of our outstanding voting securities at such time. Under the intellectual property asset purchase agreement, we also granted a non-exclusive license to Alexion and its affiliates to continue to use the assets we acquired for Alexion’s and its affiliates’ internal, non-clinical research purposes. In addition, subject to certain specified qualifications set forth in the intellectual property assets purchase agreement, Alexion is obligated to assign to us its rights with respect to any other assets owned by it that are solely related to ENPP1. Alexion is no longer a current holder of more than 5% of our voting securities.

Series A-2 Convertible Preferred Stock Financing

On March 22, 2019, we issued and sold an aggregate of 16,083,916 additional shares of our Series A-2 Convertible Preferred Stock at a price per share of $1.43 in cash, for an aggregate purchase price of $23,000,000. The following table sets forth the aggregate number of shares of our Series A-2 Convertible Preferred Stock that we issued and sold to holders of more than 5% of our voting securities at the time of such financing and their affiliates and the aggregate purchase price for such shares:

On June 5, 2020, we issued and sold an aggregate of 23,566,431 additional shares of our Series A-2 Convertible Preferred Stock at a price per share of $1.43, for an aggregate purchase price of $33,699,996. The following table sets forth the aggregate number of shares of our Series A-2 Convertible Preferred Stock that we issued and sold to holders of more than 5% of our voting securities and their affiliates at this time of such financing and the aggregate purchase price for such shares:

The foregoing shares of Series A-2 Convertible Preferred Stock converted into1,354,957 shares of our common stock upon the closingwere issued.

(3) These pre-funded warrants were exercised by means of a cashless exercise in February 2023 and 2,167,927 shares of our initial public offering.common stock were issued.

Director Affiliations

Some of our directors are or were affiliated or associated with entities which beneficially own or owned 5% or more of our voting securities, as indicated in the table below:

(1) Dr. Bhagat worked at Sofinnova Investments, Inc. from May 2017 to August 2022.

Danforth Consulting Agreement with Joseph Schlessinger

In January 2017,May 2021, we entered into aan amended and restated consulting agreement with Joseph Schlessinger, pursuantDanforth Advisors, LLC, or Danforth, an affiliate of Stephen DiPalma, our interim chief financial officer from May 2021 to which Dr. Schlessinger serves on our scientific advisory board and provides certain servicesMarch 2022. Pursuant to us related to planning, organizing and developing our research and development activities, advising on research techniques, assisting in recruiting scientists and attending meetings with investors, collaborators and strategic partners. Dr. Schlessinger was a member of our board of directors from September 2015 to May 2020. The consulting agreement is in effect until January 2022, and will automatically renew for additional successive one-year periods, unless we or

Dr. Schlessinger notify the other 30 days prior to the renewal date that the consulting agreement, will not be extended. UnderDanforth provided us with the chief financial officer services of Mr. DiPalma from May 2021 to March 2022, and Danforth continues to provide us with other services, including finance, accounting and administrative services, in exchange for fees payable to Danforth based on hourly rates. We paid Danforth approximately $0.4 million during the year ended December 31, 2021 and approximately $0.6 million during the year ended December 31, 2022. In accordance with the consulting agreement, we have agreed to pay Dr. Schlessinger at a rate of $135,000 per year and reimburse Dr. Schlessinger for reasonable out-of-pocket expenses incurred in the performance of his

services. As of March 31,May 2021, we have paid Dr. Schlessinger an aggregate of $555,242 for his consulting services. In addition, in connection with his services as a consultant, we granted Dr. Schlessingerissued to Mr. DiPalma an option to purchase 66,90715,000 shares of our common stock at an exercise price of $2.02 per share in 2019.of $15.90.

The consulting agreement may be terminated by us or by Danforth with cause, upon 30 days prior written notice, and without cause, upon 60 days prior written notice.

Registration Rights

We are a party to an investor rights agreement with certain holders of our common stock, including some of our 5% stockholders and their affiliates and entities affiliated with some of our directors. This investor rights agreement provides these holders the right, subject to certain conditions, to demand that we file a registration statement or to request that their shares be covered by a registration statement that we are otherwise filing.

We are a party to a registration rights agreement with certain holders of our common stock, including some of our executive officers. The registration rights agreement provides these holders the right, subject to certain conditions, to demand that we file a registration statement or request that their shares be covered by a registration statement that we are otherwise filing.

Indemnification Agreements

Our certificate of incorporation provides that we will indemnify our directors and officers to the fullest extent permitted by Delaware law. In addition, we have entered into indemnification agreements with all of our directors and executive officers. These indemnification agreements may require us, among other things, to indemnify each such director or executive officer for some expenses, including attorneys’ fees, judgments, fines and settlement amounts incurred by him or her in any action or proceeding arising out of his or her service as one of our directors or executive officers.

Policies and Procedures for Related Person Transactions

Our board of directors has adopted written policies and procedures for the review of any transaction, arrangement or relationship in which our company is a participant, the amount involved exceeds (i) the lesser of $120,000 and one percent of our average total assets at year end for the last two completed fiscal years, if we are a “smaller reporting company” under applicable SEC rules, or (ii) $120,000, if we are not a “smaller reporting company” under applicable SEC rules, and one of our executive officers, directors, director nominees or 5% stockholders, or their immediate family members, each of whom we refer to as a “related person,” has a direct or indirect material interest.

If a related person proposes to enter into such a transaction, arrangement or relationship, which we refer to as a “related person transaction,” the related person must report the proposed related person transaction to our general counsel, and if none, our chief operating officer or chief financial officer. The policy calls for the proposed related person transaction to be reviewed and, if deemed appropriate, approved by our audit committee. Whenever practicable, the reporting, review and approval will occur prior to entry into the transaction. If advance review and approval is not practicable, the audit committee will review, and, in its discretion, may ratify the related person transaction. The policy also permits the chair of the audit committee to review and, if deemed appropriate, approve proposed related person transactions that arise between committee meetings, subject to ratification by the committee at its next meeting. Any related person transactions that are ongoing in nature will be reviewed annually.

A related person transaction reviewed under the policy will be considered approved or ratified if it is authorized by the audit committee after full disclosure of the related person’s interest in the transaction. As appropriate for the circumstances, the audit committee will review and consider:

PRINCIPAL STOCKHOLDERS

Unless otherwise provided below, the following table sets forth information with respect to the beneficial ownership of our common stock as of March 31, 2021April 17, 2023 by:

The column entitled “Percentage of Shares Beneficially Owned” is based on a total of 23,466,13043,765,485 shares of our common stock outstanding as of March 31, 2021.April 17, 2023.

Beneficial ownership is determined in accordance with the rules and regulations of the SEC and includes voting or investment power with respect to our common stock. Shares of our common stock subject to options that are currently exercisable or exercisable within 60 days after March 31, 2021April 17, 2023 are considered outstanding and beneficially owned by the person holding the options for the purpose of calculating the percentage ownership of that person but not for the purpose of calculating the percentage ownership of any other person. Except as otherwise noted, the persons and entities in this table have sole voting and investing power with respect to all of the shares of our common stock beneficially owned by them, subject to community property laws, where applicable. Except as otherwise set forth below, the address of the beneficial owner is c/o Inozyme Pharma, Inc., 321 Summer Street, Suite 400, Boston, Massachusetts 02210.