ADVM Adverum Biotechnologies Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

SCHEDULE 14A INFORMATION

PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE

SECURITIES EXCHANGE ACT OF 1934

(Amendment No.   )

Check the appropriate box:

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

PRELIMINARY PROXY STATEMENT - SUBJECT TO COMPLETION, DATED APRIL 18, 2025

ADVERUM BIOTECHNOLOGIES, INC.

100 Cardinal Way

Redwood City, California 94063

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To be Held on June 17, 2025

, 2025

To the Stockholders of Adverum Biotechnologies, Inc.:

On behalf of the board of directors (the “Board of Directors” or the “Board”) of Adverum Biotechnologies, Inc. (“Adverum,” “we,” “us” or “our”), we cordially invite you to attend the 2025 Annual Meeting of Stockholders (the “2025 Annual Meeting”), which will be held on June 17, 2025 at 8:00 a.m., Pacific Daylight Time via a live audio webcast at www.virtualshareholdermeeting.com/ADVM2025.

At the 2025 Annual Meeting, you will be asked to consider and vote upon the following proposals:

The proxy statement and notice of annual meeting accompanying this letter provide you with more specific information concerning the proposals to be voted on at the 2025 Annual Meeting. You will also be asked to transact such other business, if any, as may properly come before the 2025 Annual Meeting or any adjournment or postponement thereof.

The record date for the 2025 Annual Meeting is April 21, 2025. Only stockholders of record at the close of business on that date may vote at the meeting or any adjournment thereof. A complete list of such stockholders will be available for examination by any stockholder for any purpose germane to the 2025 Annual Meeting beginning ten days prior to the meeting at our principal executive offices located at 100 Cardinal Way, Redwood City, California 94063. If you would like to view the list, please contact our Corporate Secretary to schedule an appointment by calling (650) 656-9323 or writing to him at the address above. In addition, the list will be available for inspection by stockholders on the virtual meeting website during the meeting by clicking on the ‘Stockholder List’ link located under the ‘Meeting Links’ section of the virtual meeting website once logged in. Under Securities and Exchange Commission rules, we are providing access to the proxy materials for the 2025 Annual Meeting to stockholders via the internet. Accordingly, you can access the proxy materials and vote at www.proxyvote.com. Instructions for accessing the proxy materials and voting are described below and in the notice of annual meeting that we will mail to our stockholders on or about                  , 2025. Your vote is very important. Whether or not you plan to attend the meeting, please carefully review the enclosed proxy statement and then cast your vote, regardless of the number of shares you hold. If you are a stockholder of record, you may vote over the internet, by telephone, or, if you request to receive a printed set of the proxy materials, by completing, signing, dating and mailing the accompanying proxy card in the return envelope. Submitting your vote via the internet or by telephone or proxy card will not affect your right to vote online if you decide to attend the 2025 Annual Meeting, which will be held virtually via the internet. If your shares are held in street name (held for your account by a broker or other nominee), you will receive instructions from your

broker or other nominee explaining how to vote your shares, and you will have the option to cast your vote by telephone or over the internet if your voting instruction form from your broker or nominee includes instructions and a toll-free telephone number or internet website to do so. In any event, to be sure that your vote will be received in time, please cast your vote by your choice of available means at your earliest convenience.

Thank you for your cooperation and continued support.

Important Notice Regarding the Availability of Proxy Materials for the 2025 Annual Meeting of Stockholders to be held on June 17, 2025 at 8:00 a.m., Pacific Daylight Time via a live audio webcast at www.virtualshareholdermeeting.com/ADVM2025.

ADVERUM BIOTECHNOLOGIES, INC.

100 Cardinal Way, Redwood City, California 94063

PROXY STATEMENT

FOR THE 2025 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON JUNE 17, 2025

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF PROXY MATERIALS

FOR THE ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON JUNE 17, 2025

This proxy statement and our Annual Report to Stockholders, which includes our Annual Report on Form 10-K for the year ended December 31, 2024, are available at http://investors.adverum.com and www.proxyvote.com.

MEETING AGENDA

We intend to mail the proxy materials for the 2025 Annual Meeting on or about           , 2025.

TABLE OF CONTENTS

In text references to our website throughout this proxy statement do not constitute incorporation by reference of the information contained at or available through our website

Effective following the filing of a Certificate of Amendment to our Amended and Restated Certificate of Incorporation, on March 21, 2024, every ten shares of our issued and outstanding common stock were automatically combined into one issued share of common stock, without any change in the par value per share, and with no fractional shares issued, which we refer to as the Reverse Split. In connection with the Reverse Split, each stock option to purchase ten shares of common stock was automatically combined into a stock option to purchase one share of common stock and the exercise prices for such options were multiplied by ten. All equity-related information presented throughout this proxy statement gives retroactive effect to the Reverse Split, which we refer to as Post-Reverse Split.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement contains forward-looking statements that involve risks and uncertainties. All statements other than statements of historical facts contained in this proxy statement are forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “will,” “would,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “intend,” “predict,” “seek,” “contemplate,” “potential” or “continue” or the negative of these terms or other comparable terminology. These forward-looking statements include, but are not limited to, statements about:

These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2024.

Any forward-looking statement in this proxy statement reflects our current views with respect to future events and is subject to these and other risks, uncertainties and assumptions relating to our operations, results of operations, industry and future growth. Given these uncertainties, you should not place undue reliance on these forward-looking statements. These forward-looking statements speak only as of the date of this proxy statement. Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this proxy statement may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future. In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this proxy statement, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

QUESTIONS AND ANSWERS

ABOUT THE 2025 ANNUAL MEETING

The following questions and answers are intended to briefly address some commonly asked questions regarding the 2025 Annual Meeting. These questions and answers may not address all questions that may be important to you as a stockholder. You should read the more detailed information contained elsewhere in this proxy statement and the documents referred to in this proxy statement.

The 2025 Annual Meeting webcast will begin promptly at 8:00 a.m., Pacific Daylight Time. We encourage you to access the meeting webcast beginning 30 minutes prior to the start time. Stockholders may participate in the 2025 Annual Meeting by visiting the website www.virtualshareholdermeeting.com/‌ADVM2025. To participate in the 2025 Annual Meeting, you will need the 16-digit control number included on your Notice, on your proxy card or on the instructions that accompanied your proxy materials.

meeting answering stockholder questions that comply with the meeting rules of conduct, which will be posted on the virtual meeting web portal. If we receive substantially similar questions, we will group such questions together and provide a single response to avoid repetition.

If you attend the virtual meeting as described above, you will be deemed to be attending in person, as provided by Delaware law.

Registered Stockholders

Stockholders of record as of the Record Date may participate in the 2025 Annual Meeting remotely by visiting the website www.virtualshareholdermeeting.com/ADVM2025. To participate in the 2025 Annual Meeting, you will need the 16-digit control number included on your Notice, on your proxy card or on the instructions that accompanied your proxy materials. Please have your proxy card, or Notice, containing your control number available to participate in the 2025 Annual Meeting remotely.

Beneficial Stockholders

Stockholders whose shares are held through a broker, bank or other nominee as of the Record Date may participate in the 2025 Annual Meeting remotely by visiting the website www.virtualshareholdermeeting.com/‌ADVM2025. Please have your Voting Instruction Form, Notice, or other communication containing your control number available to participate in the 2025 Annual Meeting remotely.

Stockholders of Record: Shares Registered in Your Name

If, at the close of business on the Record Date, your shares were registered directly in your name with our transfer agent, Equiniti Trust Company, LLC, then you are a stockholder of record. As a stockholder of record, you may vote at the 2025 Annual Meeting or vote by proxy. Whether or not you plan to attend the 2025 Annual Meeting, please vote as soon as possible by proxy over the telephone or on the internet as instructed below to ensure your vote is counted.

Beneficial Owners: Shares Registered in the Name of a Broker, Bank or Other Similar Organization

If, at the close of business on the Record Date, your shares were not held in your name, but rather in an account at a brokerage firm, bank, dealer or other similar organization, then you are the beneficial owner of shares held in “street name” and these proxy materials are being forwarded to you by that organization.

The organization holding your account is considered to be the stockholder of record for purposes of voting at the 2025 Annual Meeting. As a beneficial owner, you have the right to direct your broker or other agent how to vote the shares in your account. You are also invited to attend the 2025 Annual Meeting. Many stockholders of record will provide you with a 16-digit control number via email or in your Notice of Availability or voting instruction form in order to attend and vote your shares at the virtual 2025 Annual Meeting. If you did not receive a 16-digit control number via email or on your Notice of Availability or voting instruction form, you will be provided with other instructions from your broker, bank or other stockholder of record that must be followed, including any requirement to obtain a valid legal proxy, in order for your broker, bank or other stockholder of record to vote your shares per your instructions or to attend and vote your shares at the 2025 Annual Meeting. Many brokers, banks or other stockholders of record allow a stockholder to obtain a valid legal proxy either online or by mail, and we recommend that you contact your broker, bank or other stockholder of record to do so.

In addition, you will also be asked to transact such other business, if any, as may properly come before the 2025 Annual Meeting or any adjournment or postponement thereof.

shares at the 2025 Annual Meeting. Many brokers, banks or other stockholders of record allow a stockholder to obtain a valid legal proxy either online or by mail, and we recommend that you contact your broker, bank or other stockholder of record to do so.

Internet proxy voting may be provided to allow you to vote your shares online, with procedures designed to ensure the authenticity and correctness of your proxy vote instructions. However, please be aware that you must bear any costs associated with your internet access, such as usage charges from internet access providers and telephone companies.

If your shares are held by your broker or other agent, you should follow the instructions provided by your broker or agent.

Abstentions and broker non-votes (as described below) will be counted towards the quorum requirement. If there is no quorum, the chairperson of the meeting or the holders of a majority of shares entitled to vote at the meeting and present or represented by proxy may adjourn the 2025 Annual Meeting to another date.

If your shares are held by your broker or other agent as your nominee (that is, held beneficially in “street name”), you will receive a voting instruction form from the institution that holds your shares. Please follow the instructions included on that form regarding how to instruct your broker or other agent to vote your shares. If you do not give voting instructions to your broker or other agent, your broker or other agent can only vote your shares with respect to “routine” matters (as described below).

If you wish to submit a proposal before the stockholders or nominate a director at the 2026 Annual Meeting of Stockholders, but you are not requesting that your proposal or nomination be included in the proxy materials for that meeting, then you must follow the procedures set forth in our bylaws and, among other things, notify our Corporate Secretary in writing between February 17, 2026 and March 19, 2026. However, if the date of the 2026 Annual Meeting of Stockholders is more than 30 days before or more than 60 days after June 17, 2026, then you must give notice no later than the 90th day prior to that meeting or, if later, the 10th day following the day on which public disclosure of that annual meeting date is first made. We also advise you to review our bylaws, which contain additional requirements regarding advance notice of stockholder proposals and director nominations.

In addition to satisfying the foregoing requirements under our amended and restated bylaws, to comply with the universal proxy rules in connection with our 2026 Annual Meeting of Stockholders, stockholders who intend to solicit proxies in support of director nominees other than our nominees must provide notice to Adverum that sets forth the information required by Rule 14a-19 under the Exchange Act no later than April 18, 2026, or if the date of our 2026 Annual Meeting of Stockholders has changed by more than 30 days from the anniversary of the date of our 2025 Annual Meeting, then the notice must be provided by the later of (i) 60 days prior to the date of our 2026 Annual Meeting of Stockholders or (ii) the 10th day following the day on which public announcement of the date of our 2026 Annual Meeting of Stockholders is first made.

PROPOSAL NO. 1: ELECTION OF DIRECTORS

Board and Corporate Governance Highlights

Our Board is made up of directors with extensive experience leading and advising biotechnology and pharmaceutical companies. Our Board strives to ensure that our directors have backgrounds that collectively add significant value to our strategic decisions and enable them to provide oversight of management to ensure accountability to our stockholders. In addition, we have worked hard to strike the right balance between long-term understanding of our business and fresh external perspectives, as well as to ensure diversity within the boardroom.

We believe that a diversity of viewpoints, background, experience and other characteristics, such as gender, race, ethnicity, culture, nationality and sexual orientation, are an important part of the composition of our Board. Under our Corporate Governance Guidelines, when evaluating candidates for nomination and new directors, the Board considers candidates with diverse backgrounds in terms of knowledge, experience, skills and other characteristics in the context of our needs at that point in time with a view to creating a Board with a diversity of experience and perspectives; and includes in the pool from which new director nominees are chosen by the Board candidates with a diversity of gender, race, ethnicity, culture, nationality or sexual orientation (and any third-party engaged to identify candidates for such pool are asked to include such candidates).

Our Board’s Nominating and Corporate Governance Committee is responsible for making recommendations to our Board regarding candidates for directorships and composition and organization of our Board. Through their work, we have assembled a Board composed of members with diverse backgrounds, skills and experience, and we believe this diversity contributes to an effective and well-balanced Board that is able to provide valuable insight into, and effective oversight of, our senior management team.

Below is a breakdown of the composition of our nominees for director and directors continuing following the 2025 Annual Meeting by board independence, non-employee status, and tenure of service (as of March 31, 2025), as well as the skills and experience possessed by our nominees for director and directors continuing following the 2025 Annual Meeting across selected categories that we believe are valuable to the oversight of our business.

 

 

Our Board is diverse, including 20% women and 40% other underrepresented groups.

General

Our Board is divided into three classes. Each class has a three-year term. Except as otherwise provided by law, vacancies on our Board may be filled only by individuals elected by a majority of the remaining directors. A director elected by our Board to fill a vacancy in a particular class, including a vacancy created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until such director’s successor is elected and has qualified, or until such director’s earlier death, resignation or removal.

Our Board currently consists of ten directors and no vacancies, divided into the three following classes:

The three nominees for Class II directors are Laurent Fischer, M.D., Patrick Machado and James Scopa, each of whom has agreed to stand for election as Class II directors. Each nominee was selected by the Board upon the unanimous recommendation of the Nominating and Corporate Governance Committee. Each nominee was previously elected to our Board by our stockholders in 2022. The specific experience, qualifications, attributes and skills of each nominee that led the Board to conclude that the individual should serve as a director are described in each nominee’s biography below. If elected, each nominee will serve for a three-year term expiring at the 2028 Annual Meeting of Stockholders, or until his or her successor is elected and has qualified, or until his or her earlier death, resignation or removal.

If any of the nominees becomes unavailable for election as a result of an unexpected occurrence, shares that would have been voted for the nominee may instead be voted for the election of a substitute nominee proposed by the Board. Each person nominated for election has agreed to serve if elected. Our management has no reason to believe that any nominee will be unable to serve.

Pursuant to our Bylaws, written notice by stockholders of qualifying nominations for election to our Board of Directors must have been received by our Corporate Secretary by March 19, 2025. We did not receive any such notices, and no other nominations for election to our Board may be made by stockholders at the 2025 Annual Meeting.

OUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE “FOR ALL” OF THE THREE CLASS II NOMINEES LISTED ABOVE FOR DIRECTOR. IF NOT OTHERWISE SPECIFIED, PROXIES WILL BE VOTED “FOR ALL” THE THREE CLASS II NOMINEES LISTED ABOVE FOR DIRECTOR.

Our nominees for director and directors continuing following the 2025 Annual Meeting and their ages as of March 31, 2025 are:

The following is a brief biography and discussion of the specific attributes, qualifications, experience and skills of each nominee for director and each director whose term will continue after the 2025 Annual Meeting. Our Board and management encourage each nominee for director and each continuing director to attend our annual meetings of stockholders.

CLASS I DIRECTORS – To continue in office until the 2027 Annual Meeting of Stockholders

Soo Hong Ms. Hong has served as the chief people officer at Sunbit, a financial technology company, since January 2022. At Sunbit, Ms. Hong is responsible for all talent and human resources functions including people services, recruiting, compensation, and organizational development. Ms. Hong has also served as the founder of Laurel Pass LLC, a human capital consulting company, since 2017. Prior to joining Sunbit, Ms. Hong served as the chief people officer at National Veterinary Associates, an owner and operator of freestanding veterinary hospitals, from May 2019 to December 2021, where she was responsible for the oversight of people services, talent, recruiting, and workplace support. From September 2017 to May 2019, Ms. Hong served as the chief human resources officer at Discovery Land Company, where she was responsible for oversight of a full portfolio of HR capabilities including talent acquisition, organizational development, total rewards and HR operation. As a consultant, Ms. Hong has advised Capital One, Global Hyatt, and Pfizer on organizational, executive recruitment and engagement strategies. Ms. Hong previously served on the board of directors of CAMP. Ms. Hong received B.A. in American Studies from Wellesley College and an M.B.A. from The University of Chicago Booth School of Business. Ms. Hong has been chosen to serve on our Board due to her deep expertise in human capital management and executive and leadership development, as well as executive and board compensation design and governance serving rapidly growing organizations during periods of transformation.

Dawn Svoronos Ms. Svoronos has more than 30 years of experience in the biopharmaceutical industry, including extensive commercial work with the multinational pharmaceutical company Merck & Co. Inc., where she held roles of increasing seniority over more than 20 years of service. Prior to her retirement from Merck in 2011, Ms. Svoronos most recently served as president of Merck in Europe/Canada from 2009 to 2011, president of Merck in Canada from 2006 to 2009 and vice president of Merck for Asia Pacific from 2005 to 2006. Ms. Svoronos currently serves as the chair of the board of directors of Xenon Pharmaceuticals Inc. and sits on the boards of directors of ACELYRIN, INC. and Theratechnologies, Inc. Previously, Ms. Svoronos served on the boards of directors of Endocyte, Inc., Global Blood Therapeutics, Inc., and PTC Therapeutics, Inc. Ms. Svoronos also serves on the board of directors of Agnovos Healthcare Company, a privately held biotechnology company. She received a B.A. in English and French literature from Carleton University in Ottawa, Canada. Ms. Svoronos has been chosen to serve on our Board due to her extensive global biopharmaceutical and commercial leadership experience.

Reed Tuckson, M.D. Dr. Tuckson has served as the managing director of Tuckson Health Connections, a private consulting company since 2013. Previously, he served as the executive vice president and chief of medical affairs of UnitedHealth Group, a managed care company. Dr. Tuckson also served as senior vice president for professional standards of the American Medical Association; president of the Charles R. Drew University of Medicine and Science; senior vice president for programs of the March of Dimes Birth Defects Foundation; and Commissioner of Public Health for the District of Columbia. Dr. Tuckson is the co-founder of the Black Coalition Against COVID, currently serves on the board of directors of Henry Schein, Inc. and is a cofounder of the Coalition For Trust In Health & Science. Dr. Tuckson previously served on the boards of directors of Acasti Pharma, Inc., CTI BioPharma Corp. and LifePoint Health, Inc. Dr. Tuckson received a B.S. from Howard University and his M.D. from the Georgetown University School of Medicine. He completed the Hospital of the University of Pennsylvania’s General Internal Medicine Residency and Fellowship programs. Dr. Tuckson has been chosen to serve on our Board due to his experience in multiple facets of the healthcare industry, including extensive healthcare policy expertise, from clinical services administration and medical policies to consumer health engagement.

CLASS II DIRECTORS – To be elected for a three-year term expiring at the 2028 Annual Meeting of Stockholders

Laurent Fischer, M.D. Dr. Fischer has served as our chief executive officer since June 2020 and our president since June 2021, and served as our interim chief medical officer from October 2021 to February 2022. Prior to that, Dr. Fischer served as senior vice president, head of the liver therapeutic area at Allergan PLC, a global pharmaceutical company, from November 2016 to June 2020, in which role he was responsible for the

R&D pipeline. Dr. Fischer served as chief executive officer of Tobira Therapeutics, a clinical-stage biopharmaceutical company from 2013 until Allergan acquired Tobira Therapeutics in November 2016, in which role he was responsible for taking the company public. Prior to that, he served as chairman and chief executive officer of Jennerex, Inc., until its acquisition by SillaJen Biotherapeutics, Inc. Dr. Fischer serves on the board of directors at Mirum Pharmaceuticals, Inc and atai Life Sciences, N.V. Additionally, Dr. Fischer serves as the chairman of the board of directors of Teal Omics and on the board of directors of Lycia Therapeutics, privately held companies. Dr. Fischer previously served as chairman of the board of directors of CTIC Biopharma until its sale to SOBI in July 2023. Over his career, Dr. Fischer has held leadership roles at several companies, including as CEO of Ocera Therapeutics, President of Auxeris Therapeutics of RXCentric, Inc. (now part of Allscripts Healthcare Solutions, Inc.), MedVantx Inc., Dupont Pharmaceuticals, Dupont-Merck and F. Hoffmann-La Roche. Dr. Fischer received an undergraduate degree from the University of Geneva and his medical degree from the Geneva Medical School, Switzerland. Dr. Fischer’s experience as an executive in the pharmaceutical industry, knowledge of biopharmaceuticals, and his service as our Chief Executive Officer were the primary qualifications that led the Board to conclude that he should serve on our Board.

Patrick Machado Mr. Machado was a co-founder of Medivation, Inc., a biopharmaceutical company, and served as its chief business officer from 2009 to 2014 and as its chief financial officer from 2004 until his retirement in 2014. From 1998 to 2001, Mr. Machado worked with ProDuct Health, Inc., a medical device company, as senior vice president, chief financial officer and earlier as general counsel. Upon ProDuct Health’s acquisition by Cytyc Corporation, a diagnostic and medical device company, he served as a consultant to Cytyc to assist with transitional matters from 2001 to 2002. Mr. Machado currently serves on the boards of directors of ACELYRIN, INC., Alumis Inc., Arcus Biosciences, Inc. and Xenon Pharmaceuticals Inc., all of which are publicly traded biopharmaceutical companies, and Avenzo Therapeutics Inc. and Prota Therapeutics, both privately held biopharmaceutical companies, and previously served on the boards of Chimerix, Inc., Medivation, Inc., Principia Biopharma Inc., Roivant Sciences Ltd., Turning Point Therapeutics, Inc. and Turnstone Biologics Corp. Mr. Machado received a B.A. in German and a B.S. in Economics from Santa Clara University and a J.D. from Harvard Law School. Mr. Machado has been chosen to serve on our Board due to his extensive experience dealing with the operational and financial issues of biopharmaceutical companies.

James Scopa Mr. Scopa served on the investment committee of MPM Capital, a life sciences venture capital firm, and was a managing director in MPM Capital’s San Francisco office from 2005 to 2017. Previously, Mr. Scopa spent 18 years advising growth companies in biopharmaceuticals and medical devices at Deutsche Banc/Alex. Brown & Sons and Thomas Weisel Partners. At Deutsche Banc Alex. Brown he served as managing director and Global Co-Head of Healthcare Investment Banking. Mr. Scopa has been a member of the board and advisory board of Hevolution, LLC since November 2023 and a member of the advisory board and investment advisory committee of OneVentures, an Australian venture capital firm, since July 2017. Mr. Scopa currently serves on the boards of directors of Aligos Therapeutics, Inc., a publicly traded biopharmaceutical company, and privately held Neuron23, Inc. Mr. Scopa has previously served on the boards of directors of DICE Therapeutics, Inc. (sold to Eli Lilly and Company) and Blade Therapeutics, Inc. Mr. Scopa received an A.B. from Harvard College, an M.B.A. from Harvard Business School and a J.D. from Harvard Law School. Mr. Scopa has been chosen to serve on our Board due to his extensive experience as a venture capital investor in the biotechnology and biopharmaceuticals industries, prior experience as an investment banker in those industries, and his service as a director for numerous companies.

CLASS III DIRECTORS – To continue in office until the 2026 Annual Meeting of Stockholders

Szilárd Kiss, M.D. Dr. Kiss has been at the Department of Ophthalmology at the Weill Cornell Medical College of Cornell University (“Weill”) since 2008, where he has served in various roles, and is currently the Bob and Dolores Hope – Robert M. Ellsworth, M.D. Distinguished Professor in Ophthalmology (since April 2023), Professor of Ophthalmology in Genetic Medicine (since May 2023) and Chief of the Retina Service (since August 2015). Dr. Kiss serves as Senior Councilor (since July 2021) and is also the Associate Dean of Clinical Compliance (since November 2019). Dr. Kiss first joined Weill as Assistant Professor of Ophthalmology in 2008. Dr. Kiss also serves as Chief Medical Officer of Blue Gen Therapeutics Foundation, a nonprofit biotechnology corporation developing gene therapy treatments for rare inherited retinal diseases. Dr. Kiss also consults for or serves on the advisory board of a number of biopharmaceutical companies, and previously consulted for the Company. Dr. Kiss holds a B.A. in Biology from Columbia College and an M.D. from

Columbia University Vagelos College of Physicians and Surgeons. Dr. Kiss completed his ophthalmology residency and surgical vitreoretinal fellowship at Harvard Medical School and the Massachusetts Eye & Ear Infirmary. Dr. Kiss has been chosen to serve on the Company’s Board due to his expertise in ophthalmology, gene therapy, and compliance and regulatory matters.

Mark Lupher, Ph.D. Dr. Lupher served as vice president of translational pharmacology and preclinical development at Sutro Biopharma, Inc., a publicly traded drug discovery, development and manufacturing company, from February 2016 to March 2020. In June 2013, Dr. Lupher founded VeritasRx Consulting, a consulting firm, and he has served as its president since that time, consulting for venture capital firms and biopharmaceutical companies, including Sutro Biopharma, Inc. from May 2014 to March 2016. Prior to VeritasRx, Dr. Lupher held various roles with Promedior, Inc., where he served as chief scientific officer from June 2010 to June 2013, as senior vice president, discovery research from June 2009 to June 2010 and as vice president, drug discovery from February 2007 to June 2009. Dr. Lupher received a Ph.D. in immunology from Harvard University and a B.S. in microbiology from the University of Washington. Dr. Lupher has been chosen to serve on our Board due to his drug development experience.

C. David Nicholson, Ph.D. Dr. Nicholson served as the executive vice president and chief research and development officer of Allergan plc, a pharmaceutical company, which was acquired by AbbVie Inc. in May 2020, from March 2015 to August 2020. He initially joined Allergan as senior vice president, Actavis Global Brands R&D, in August 2014. Prior to Allergan, from March 2012 to July 2014, Dr. Nicholson served on the executive committee of Bayer Crop Science, a pharmaceutical and biotechnology company, as chief technology officer and executive vice president of research and development. Dr. Nicholson currently serves as the non-executive chair of the board of directors of Wild Bioscience, a member of the board of directors of Volastra and Rapalogix, the lead independent director of Actinium Pharmaceuticals, Inc. and an operational partner at Gilde Healthcare. Dr. Nicholson previously served as the non-executive chair of the board of directors of Exscientia plc. Dr. Nicholson received a B.Sc. in Pharmacology from the University of Manchester and a Ph.D. from the University of Wales. Dr. Nicholson has been chosen to serve on our Board due to his extensive pharmaceutical experience, a proven track record in drug development and deep experience in ophthalmology.

Scott Whitcup, M.D. Dr. Whitcup is the founder and chief executive officer of two companies focused on developing new therapies in ophthalmology and dermatology, Akrivista LLC and Whitecap Therapeutics LLC, positions he has held since October 2015 and October 2024, respectively. He has also served on the clinical faculty at the UCLA Stein Eye Institute since July 2003. Previously, Dr. Whitcup served in a number of positions at Allergan, Inc., most recently as the executive vice president of research and development and chief scientific officer, from April 2009 to March 2015. Earlier in his career, Dr. Whitcup was the clinical director at the National Eye Institute at the National Institutes of Health. He previously served on the board of directors of Menlo Therapeutics Inc., a biopharmaceutical company, and currently serves on the board of directors of Anivive Lifesciences, a private company. Dr. Whitcup received a B.A. from Cornell University and an M.D. from Cornell University Medical College. He completed an internal medicine residency at UCLA and an ophthalmology residency at Harvard University at the Massachusetts Eye and Ear Infirmary. Dr. Whitcup has been chosen to serve on our Board due to his extensive experience in the discovery, development, and commercialization of drug products, his ophthalmologic expertise and his experience serving as a director for numerous companies.

PROPOSAL NO. 2: RATIFICATION OF SELECTION OF

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

General

The Audit Committee of our Board has selected Ernst & Young LLP as our independent registered public accounting firm for the year ending December 31, 2025, and is seeking ratification of such selection by our stockholders at the 2025 Annual Meeting. Ernst & Young LLP has served as our independent registered public accounting firm since 2018. Representatives of Ernst & Young LLP are expected to be present at the 2025 Annual Meeting. They will have an opportunity to make a statement if they so desire and will be available to respond to appropriate questions.

Neither our bylaws nor other governing documents or law require stockholder ratification of the selection of Ernst & Young LLP as our independent registered public accounting firm. However, the Audit Committee is submitting the selection of Ernst & Young LLP to our stockholders for ratification as a matter of good corporate practice. If our stockholders fail to ratify the selection, the Audit Committee will reconsider whether or not to retain Ernst & Young LLP. Even if the selection is ratified, the Audit Committee in its discretion may select a different independent registered public accounting firm at any time during the year if they determine that such a change would be in the best interests of Adverum and our stockholders.

Auditor Fees

For the years ended December 31, 2024 and 2023, Ernst & Young LLP billed the approximate fees set forth below. All fees described in the table below were preapproved by the Audit Committee.

Preapproval Policies and Procedures

The Audit Committee is responsible for reviewing the terms of the proposed engagement of the independent registered public accounting firm for audit or permissible non-audit services and for preapproving all such engagements. The Audit Committee has adopted a policy for the preapproval of all audit and non-audit services to be performed for us by the independent registered public accounting firm. In providing any preapproval, the Audit Committee considers whether the services to be approved are consistent with the SEC’s rules on auditor independence. The Audit Committee has considered the role of Ernst & Young LLP in providing audit and audit-related services to us and has concluded that such services are compatible with Ernst & Young LLP’s role as our independent registered public accounting firm.

OUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE “FOR” THE RATIFICATION OF ERNST & YOUNG LLP AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE YEAR ENDING DECEMBER 31, 2025. IF NOT OTHERWISE SPECIFIED, PROXIES WILL BE VOTED “FOR” THE APPROVAL OF THIS PROPOSAL.

REPORT OF THE AUDIT COMMITTEE OF THE BOARD OF DIRECTORS

The primary purpose of the Audit Committee is to oversee our financial reporting processes on behalf of our Board. The Audit Committee’s functions are more fully described in its charter, which is available on our website at http://investors.adverum.com/governance/.

In fulfilling its oversight responsibilities, the Audit Committee reviewed and discussed with management Adverum’s audited financial statements for the year ended December 31, 2024. The Audit Committee has discussed with Ernst & Young LLP (“E&Y”), Adverum’s independent registered public accounting firm for 2024, the matters required to be discussed by the applicable requirements of the Public Company Accounting Oversight Board (“PCAOB”) and the Securities and Exchange Commission. In addition, the Audit Committee received from E&Y the written disclosures and the letter required by the applicable requirements of the PCAOB regarding E&Y’s communications with the Audit Committee concerning independence, and has discussed with E&Y its independence. Finally, the Audit Committee discussed with E&Y, with and without management present, the scope and results of E&Y’s audit of our financial statements for the year ended December 31, 2024.

Based on these reviews and discussions, the Audit Committee recommended to our Board that our audited financial statements be included in our Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC.

Audit Committee

Patrick Machado

James Scopa

Dawn Svoronos

PROPOSAL NO. 3: ADVISORY VOTE ON EXECUTIVE COMPENSATION

Under the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) and Section 14A of the Exchange Act, our stockholders are entitled to vote to approve, on an advisory basis, the compensation of our named executive officers as disclosed in this proxy statement in accordance with SEC rules.

Accordingly, the Board is asking you to indicate your support for the compensation of our named executive officers as described in this proxy statement by casting a non-binding advisory vote “FOR” the following resolution:

“RESOLVED, that the compensation paid to Adverum’s named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including the compensation discussion and analysis, compensation tables and narrative discussion, is hereby APPROVED.”

Because the vote is advisory, it is not binding on our Board, our Compensation Committee or us. Nevertheless, the views expressed by the stockholders, whether through this vote or otherwise, are important to management and the Board and, accordingly, the Board and the Compensation Committee intend to consider the results of this vote in making determinations in the future regarding executive compensation arrangements.

As most recently approved by stockholders at the annual meeting of stockholders in 2020, and consistent with our Board’s recommendation, we are submitting this proposal for a non-binding vote on an annual basis. The next stockholder vote on the frequency of a stockholder vote on the compensation of the named executive officers will occur no later than at the Company’s 2026 Annual Meeting of Stockholders.

OUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE “FOR” THE ADVISORY VOTE ON EXECUTIVE COMPENSATION. IF NOT OTHERWISE SPECIFIED, PROXIES WILL BE VOTED “FOR” THE APPROVAL OF THIS PROPOSAL.

PROPOSAL NO. 4: APPROVAL OF AMENDMENT AND RESTATEMENT OF THE ADVERUM

BIOTECHNOLOGIES, INC

2024 EQUITY INCENTIVE AWARD PLAN

Executive Summary

As of March 31, 2025, there are only 29,097 shares available for grant under our 2024 Equity Incentive Award Plan (the “2024 Plan”), which is the only equity plan we can use for grants to our existing employees (including executives), directors, certain new hires and consultants. Equity compensation is a critical element of our compensation and retention program, and our equity compensation program is managed thoughtfully. With the share reserve under the 2024 Plan nearly exhausted, failing to replenish it will render our equity incentive plan ineffective. Consequently, we believe this will hinder our ability to align employee interests with long-term stockholder value and there is a high probability it will impair our efforts to retain or attract critical talent.

Accordingly, we are requesting stockholder approval of an amendment and restatement of the 2024 Plan. We refer to the amended and restated 2024 Plan in this proxy statement as the “Amended 2024 Plan.” The only differences between the 2024 Plan and the Amended 2024 Plan are that the Amended 2024 Plan:

Why We Are Asking Our Stockholders to Approve the Amended 2024 Plan

The 2024 Plan was approved by our Board on April 29, 2024, and by our stockholders at the 2024 Annual Meeting on June 17, 2024. The Amended 2024 Plan was approved by our Board on April 16, 2025, subject to stockholder approval at this Annual Meeting. We are seeking stockholder approval of the Amended 2024 Plan to increase the number of shares available thereunder by 2,100,000 shares, which will allow us to grant equity awards at levels determined appropriate by our Compensation Committee, pursuant to the Board’s delegation of such authority to the Compensation Committee. Also, the limit on the number of shares that may be granted subject to incentive stock options is being increased to match the new aggregate share pool under the Amended 2024 Plan.

The Amended 2024 Plan will allow us to attract, retain and motivate employees, consultants and directors through the granting of stock-based compensation awards and thereby to align employees’, consultants’ and directors’ interests with value creation for stockholders. Our Board believes that the Amended 2024 Plan is an integral part of our compensation philosophy, aligning employees’ and stockholder’s interests, and that the Amended 2024 Plan is necessary to continue providing the appropriate levels and types of equity compensation.

We currently make equity award grants under the 2024 Plan and our 2017 Inducement Plan. As of March 31, 2025, there were 29,097 shares available for equity award grants under the 2024 Plan. The 2017 Inducement Plan can only be used for grants to new employees and cannot be used to make grants to retain existing employees or generally to make grants to consultants or directors. If the Amended 2024 Plan is not approved by our stockholders, the existing 2024 Plan will continue in effect, but we will be severely limited in the grants that we will be able to make to existing employees, directors and consultants. These circumstances would place us in a disadvantageous position compared with our competitors, resulting in challenges with respect to employee recruitment and retention. Without the approval of the Amended 2024 Plan and an additional share reserve, we will be less able to compete effectively in the talent marketplace. This could ultimately result in the loss of critical talent and inhibit our ability to meet our future objectives. In addition, without the approval of the Amended 2024 Plan, we may need to significantly boost the cash compensation elements of our program to compensate for the lack of equity-based incentives. These potential outcomes would significantly hinder our ability to align our executives' interests with those of our stockholders, recruit and retain new executives, key employees, and non-employee directors, and motivate our current executives and key employees over the long term.

Requested Shares

Subject to adjustment for certain changes in our capitalization, if this Proposal No. 4 is approved by our stockholders, the aggregate number of shares of common stock that may be issued under the Amended 2024 Plan will be equal to the sum of (i) 2,100,000 new shares of common stock; (ii) the 2,160,600 shares of common

stock originally reserved under the 2024 Plan and (iii) any of the shares of common stock which as of the original effective date of the 2024 Plan are available for issuance under our 2014 Equity Incentive Award Plan (the “2014 Plan”), or are subject to awards under the 2014 Plan that, on or after the original effective date of the original 2024 Plan, terminate, expire or lapse for any reason without the delivery of shares of common stock to the holder thereof, up to a maximum of 4,514,896 shares of common stock.

To the extent that an award terminates, expires or lapses for any reason or an award is settled in cash without the delivery of shares, any shares subject to the award at such time will be available for future grants under the Amended 2024 Plan. However, the following shares shall not be available for future grants of awards under the Amended 2024 Plan: (a) shares tendered to or withheld to satisfy the grant, exercise price or tax withholding obligation with respect to an award under the Amended 2024 Plan; (b) shares subject to a stock appreciation right that are not issued in connection with the stock settlement of the stock appreciation right on exercise thereof; and (c) shares repurchased on the open market with the cash proceeds from the exercise of options.

To the extent that shares of our common stock are repurchased by us prior to vesting at the same price paid by the holder (or a lower price) so that shares are returned to us, such shares will be available for future grants under the Amended 2024 Plan. The payment of dividend equivalents in cash in conjunction with any outstanding awards will not be counted against the shares available for issuance under the Amended 2024 Plan. To the extent permitted by applicable law or any exchange rule, shares issued in assumption of, or in substitution for, any outstanding awards of any entity acquired in any form of combination by us or any of our subsidiaries will not be counted against the shares available for issuance under the Amended 2024 Plan.

Why We Believe It Is Important to Vote to Approve the 2024 Plan

Equity Awards Are an Important Part of Our Compensation Philosophy

Our Board believes that our future success largely hinges on our ability to competitively retain and motivate our employees, consultants, and directors. Issuing equity awards is crucial to achieving these goals, as it effectively links pay to performance and aligns employee interests with those of our stockholders, providing employees, directors and consultants a means to benefit from increased stock value over time. Our incentive programs are designed to incentivize progress on our strategic priorities. Our 2024 corporate objectives included an emphasis on advancing clinical development of Ixo-vec through presentation of key data from the LUNA and OPTIC trials to enable the dose selection and prophylaxis regimen for registrational trials. In November 2024 we announced top-line 52-week results from the ongoing LUNA Phase 2 clinical trial, and in March 2025, we initiated the ARTEMIS Phase 3 clinical trial of Ixo-vec in wet age-related macular degeneration (“wet AMD”). Additional strategic priorities included Ixo-vec CMC, advancing our pipeline, employee engagement and fiscal responsibility.

Historically, we have granted initial and annual equity awards to all our employees, non-employee directors and certain consultants, believing that a culture of ownership is important to our ability to achieve our short- and long-term business objectives and that our success is dependent on our employees, directors and consultants feeling invested in our future. Since the approval of the 2024 Plan on June 17, 2024, we have granted equity awards to 163 employees, directors and consultants. Also, equity awards were key to aur ability to continue to attract and retain talented executive management in key positions to support our goals and priorities. The Amended 2024 Plan will allow us to continue to provide performance-based incentives to our eligible employees, consultants and directors to incentivize achievement of our strategic imperatives going forward. Therefore, the Board believes that the approval of this Proposal No.4 is instrumental to our ongoing success and our ability to provide increased value to our stockholders and thus in the best interests of the Company and its stockholders and recommends a vote in favor of this Proposal No.4.

The Size of Our Share Reserve Request Is Reasonable and Our Current Share Pool is Significantly Depleted

As of March 31, 2025, we had 29,097 shares available for grant under the 2024 Plan. If the Amended 2024 Plan and the new share reserve of 2,100,000 shares is approved by our stockholders, we will have 2,129,097 shares available for grant under the Amended 2024 Plan immediately after the Annual Meeting (based on shares available as of March 31, 2025), which we believe will be sufficient for us to grant equity awards for approximately one year.

This share reserve request is designed to enable us to grant equity awards in the coming year in alignment with our compensation philosophy. Our compensation philosophy is designed to motivate and retain employees, directors and certain consultants to support execution on our strategic activities, including our two Phase 3 trials, planned pre-BLA activities and pre-commercial activities, all of which are designed to build stockholder value. In addition, the request takes into account our projected continued company growth supporting these activities, including option grants to new hires who have previously been consultants and are therefore ineligible for new-hire grants under our 2017 Inducement Plan.

If the Amended 2024 Plan is not approved by our stockholders, the existing 2024 Plan will continue in effect, but we will be extremely limited in the grants that we will be able to make: we will not have adequate shares to continue to grant equity awards to the vast majority of our service providers or to make grants of a size to provide appropriate retentive and incentive value. This would place us in a disadvantageous position as compared with our competitors, potentially resulting in reduced retention and possibly requiring us to use cash to retain and incentivize our employees, consultants and directors, rather than using that cash for other business purposes. Indeed, the 29,097 shares remaining under the 2024 Plan as of March 31, 2025 will not be sufficient for us to continue to grant equity awards to our existing employees (including executives), directors and consultants consistent with our compensation philosophy and policies.

We Manage Our Equity Incentive Award Use Thoughtfully To Avoid Unnecessary Dilution

We continue to believe that equity awards are a vital part of our overall compensation program by providing incentives for our employees to exert their maximum efforts for our success, ultimately contributing to the creation of stockholder value. However, we recognize that equity awards dilute existing stockholders, and, therefore, we must responsibly manage the growth of our equity compensation program. We remain committed to effectively monitoring our equity compensation share reserve, including our “burn rate,” to ensure that we maximize stockholders’ value by granting the appropriate number of equity incentive awards necessary to attract and retain employees.

The Company has historically granted long-term equity incentive awards to all of its employees. We believe this high level of participation in our broad-based equity compensation program aligns the interests of all employees and directors with those of stockholders. This strong employee ownership philosophy drives a higher level of overhang, but we believe it is essential to the future success of the Company and our stockholders. With this in mind, the Company is committed to continually incentivizing and retaining all employees through equity compensation while managing overhang and burn rate in order to drive long-term success.

Overhang

“Overhang” generally refers to the total number of equity awards outstanding plus the total number of shares available for grant under our equity plans, divided by the sum of the total common stock outstanding, the number of equity awards outstanding and the total number of shares available for grant under our equity plans. The following table provides certain additional information regarding our Equity Plans.

Historical Burn Rate

The following table provides detailed information regarding the activity related to all of our equity incentive plans for fiscal years 2024, 2023 and 2022.

Our historical burn rate has been higher than the burn rate of some of our peer group companies, as defined in the section below titled “Compensation Discussion and Analysis—Competitive Market Pay Information,” and in particular the discussion of the 2024 Peer Group, as defined in that section. The higher burn rate has been a result of a number of factors many of which were outside the control of the Company and our employees, directors or consultants. First, the market price of our common stock has been subject to material fluctuations in recent years and has declined from a five-year high of over $246.00 in June 2020 to approximately $4.37 on March 31, 2025. As a result, nearly all of our employees, directors, and consultants now hold options that are significantly underwater. The average strike prices of the option awards held by our employees, excluding executive officers; our executive officers, as a group; and non-employee directors, as a group, as of March 31, 2025, were $16.74, $30.56 and $41.41, respectively compared to the $4.37 closing price for our common stock on that day. Consequently, in some periods, in order to provide equity awards of a particular value in alignment with our compensation philosophy during times that the price has been lower, we had to utilize a higher number of shares from our Equity Plans. In some other periods, we provided smaller equity awards with a lower value than would be in alignment with our compensation philosophy.

Despite our stock price decline, the Company has continued to hire an experienced and talented team at all levels, supporting substantial progress in advancing the development of our lead program, Ixo-vec. This has been facilitated by our ability to utilize equity as part of the compensation package. We have issued equity awards designed to align the interests of employees and directors with those of stockholders and to attract, reward, and retain talent to achieve our strategic objectives. This approach was exemplified by the out-of-cycle equity awards made in September 2022 and the long-term equity incentive grants in August 2024, which partially addressed the dilution of equity grants due to the early 2024 financing.

In line with the Company's approach, most of the 2,160,600 shares of common stock originally reserved under the 2024 Plan and approved by the stockholders at the 2024 Annual Meeting on June 17, 2024 were granted to our employees pursuant to the August 2024 long-term equity incentive grants and the March 2025 long-term equity incentive refresh grants. A much smaller proportion of these shares was granted to new hires who were ineligible to receive grants under our 2017 Inducement Plan, and to non-executive directors and other key consultants. As a result, as of March 31, 2025, we had only 29,097 shares available for grants under the 2024 Plan.

Additionally, the grant date fair value of the equity awards we have granted has been modest in recent years as we have granted options based on peer group company ownership benchmarks and not based on absolute compensation benchmarks.

The following table sets forth, as of March 31, 2025: the aggregate number of shares of common stock subject to full value awards, options and total equity awards held by our executive officers and shares subject to total equity awards as a percent of our shares and pre-funded warrants.

Historical Awards Granted

The following table sets forth, for each of the individuals and various groups indicated: the total number of shares of our common stock subject to option and full value awards that were granted under our equity plans in each of fiscal years 2024, 2023 and 2022 and the grant date fair value of such awards as identified in the Summary Compensation Table in “Executive Compensation, Compensation Discussion and Analysis, Determination of Executive Officer Compensation” below.

Key Plan Features

As was the case with the 2024 Plan, the Amended 2024 Plan includes provisions that are designed to protect our stockholders’ interests and to reflect corporate governance best practices including:

Description of the 2024 Plan

The material features of the Amended 2024 Plan are described below. The following description of the Amended 2024 Plan is a summary only and is qualified in its entirety by reference to the complete text of the 2024 Plan. Stockholders are urged to read the actual text of the Amended 2024 Plan in its entirety, which is appended as Appendix A to the copy of this proxy statement filed with the SEC, which may be accessed from the SEC’s website at www.sec.gov.

General. The Amended 2024 Plan provides for the grant of incentive stock options to our employees and employees of certain affiliates, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards, dividend equivalent awards, deferred stock awards, deferred stock unit awards, stock payment awards to our employees, directors and consultants and the employees and consultants of our affiliates.

Authorized Shares and Share Counting Provisions. Subject to adjustment for certain changes in our capitalization, if this Proposal No.4 is approved by our stockholders, the aggregate number of shares of common stock that may be issued under the Amended 2024 Plan will be equal to the sum of (i) 2,100,000 new shares of common stock; (ii) the 2,160,600 shares of common stock originally reserved under the 2024 Plan; and (iii) any of the shares of common stock which as of the effective date of the original 2024 Plan are available for issuance under the 2014 Plan, or are subject to awards under the 2014 Plan that, on or after the original effective date of the 2024 plan, terminate, expire or lapse for any reason without the delivery of shares of common stock to the holder thereof, up to a maximum of 4,514,896 shares of common stock.

To the extent that an award terminates, expires or lapses for any reason or an award is settled in cash without the delivery of shares, any shares subject to the award at such time will be available for future grants under the Amended 2024 Plan. However, the following shares shall not be available for future grants of awards under the Amended 2024 Plan: (a) shares tendered to or withheld to satisfy the grant, exercise price or tax withholding obligation with respect to an award under the Amended 2024 Plan; (b) shares subject to a stock appreciation right that are not issued in connection with the stock settlement of the stock appreciation right on exercise thereof; and (c) shares repurchased on the open market with the cash proceeds from the exercise of options.

To the extent that shares of our common stock are repurchased by us prior to vesting at the same price paid by the holder (or a lower price) so that shares are returned to us, such shares will be available for future grants under the Amended 2024 Plan. The payment of dividend equivalents in cash in conjunction with any outstanding awards will not be counted against the shares available for issuance under the Amended 2024 Plan. To the extent permitted by applicable law or any exchange rule, shares issued in assumption of, or in substitution for, any outstanding awards of any entity acquired in any form of combination by us or any of our subsidiaries will not be counted against the shares available for issuance under the Amended 2024 Plan.

The aggregate maximum number of shares of common stock that may be issued pursuant to the exercise of incentive stock options is 4,514,896 shares.

Plan Administration. The Compensation Committee administers the Amended 2024 Plan unless our Board of Directors assumes authority for administration. The Amended 2024 Plan provides that the Board or Compensation Committee may delegate its authority to grant awards to employees other than executive officers and certain senior executives of the company to a committee consisting of one or more members of our Board of Directors or one or more of our officers. Subject to the terms and conditions of the Amended 2024 Plan, the administrator has the authority to select the persons to whom awards are to be made, to determine the number of shares to be subject to awards and the terms and conditions of awards, and to make all other determinations and to take all other actions necessary or advisable for the administration of the Amended 2024 Plan. The administrator is also authorized to adopt, amend or rescind rules relating to administration of the Amended 2024 Plan.

No Repricing Without Stockholder Approval. Without the approval of the stockholders of the Company, the terms of outstanding awards may not be amended to (i) reduce the exercise price or grant price of an outstanding option or stock appreciation right, (ii) grant a new option, stock appreciation right or other award in substitution for, or upon the cancellation of, any previously granted option or stock appreciation right that has the effect of reducing the exercise price or grant price thereof, (iii) exchange any option or stock appreciation right for shares of common stock, cash or other consideration when the exercise price or grant price per share of common stock under such option or stock appreciation right equals or exceeds the fair market value of a share of common stock or (iv) take any other action that would be considered a “repricing” of an option or stock appreciation right under the applicable listing standards of the national securities exchange on which the common stock is listed.

Dividends and Dividend Equivalents; No Payment Until Vesting of the Underlying Award. The Amended 2024 Plan provides that dividends or dividend equivalents may be paid or credited with respect to any shares of our common stock subject to an award (other than an option or stock appreciation right), as determined by the plan administrator and contained in the applicable award agreement, but no dividends or dividend equivalents may be paid with respect to any such shares before the date such shares have vested.

Types of Awards

Changes to Capital Structure. In the event there is a specified type of change in our capital structure, such as a stock split, reverse stock split or recapitalization, appropriate adjustments will be made to (1) the class and maximum number of shares reserved for issuance under the Amended 2024 Plan, (2) the class and maximum number of shares that may be issued upon the exercise of incentive stock options and (3) the class and number of shares and exercise price, strike price or purchase price, if applicable, of all outstanding stock awards.

Dissolution or Liquidation. In the event of a dissolution or liquidation of the Company, all outstanding awards (other than awards consisting of vested and outstanding shares of common stock not subject to a forfeiture condition or the Company’s right of repurchase) will generally terminate immediately prior to the completion of the dissolution or liquidation, and the shares of common stock subject to the Company’s repurchase rights or subject to a forfeiture condition may be repurchased or reacquired by the Company notwithstanding the fact that the holder of such award is still providing services; provided, however, that the administrator may determine to cause some or all awards to become fully vested, exercisable and/or no longer subject to repurchase or forfeiture (to the extent such awards have not previously expired or terminated) before the dissolution or liquidation is completed but contingent on its completion.

Change in Control. The terms below will apply to awards in the event of a change in control (as defined in the Amended 2024 Plan), unless otherwise provided in the instrument evidencing the award or any other written agreement between the Company or any affiliate and the participant or unless otherwise expressly provided by the administrator at the time of grant of an award:

the “Current Holders”), the vesting of such awards (and, with respect to options and stock appreciation rights, the time when such awards may be exercised) will be accelerated in full to a date prior to the effective time of such change in control (contingent upon the effectiveness of the change in control) as the administrator determines, and such awards will terminate if not exercised (if applicable) at or prior to the effective time of the change in control, and any reacquisition or repurchase rights held by the Company with respect to such Awards will lapse (contingent upon the effectiveness of the change in control). With respect to the vesting of performance awards that will accelerate upon the occurrence of a Change in Control and that have multiple vesting levels depending on the level of performance, the vesting of such performance awards will accelerate at 100% of the target level upon the occurrence of the change in control.

Transferability. A participant may not transfer stock awards under the Amended 2024 Plan other than by will, the laws of descent and distribution or as otherwise provided under the Amended 2024 Plan.

Plan Amendment or Termination. Our Board has the authority to amend, suspend or terminate the Amended 2024 Plan, provided that such action does not materially impair the existing rights of any participant without such participant’s written consent. Certain material amendments also require the approval of our stockholders.

U.S. Federal Income Tax Consequences

The information set forth below is a summary only and does not purport to be complete. The information is based upon current federal income tax rules and therefore is subject to change when those rules change. Because the tax consequences to any recipient may depend on his or her particular situation, each recipient should consult the recipient’s tax adviser regarding the federal, state, local, and other tax consequences of the grant or exercise of an award or the disposition of stock acquired as a result of an award. The Amended 2024 Plan is not qualified under the provisions of Section 401(a) of the Code and is not subject to any of the provisions of the Employee Retirement Income Security Act of 1974.

Nonstatutory Stock Options

Generally, there is no taxation upon the grant of a nonstatutory stock option if the stock option is granted with an exercise price equal to the fair market value of the underlying stock on the grant date. On exercise, an optionholder will recognize ordinary income equal to the excess, if any, of the fair market value on the date of exercise of the stock over the exercise price. If the optionholder is employed by us or one of our affiliates, that income will be subject to withholding taxes. We will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the optionholder.

Incentive Stock Options

The Amended 2024 Plan provides for the grant of stock options that qualify as “incentive stock options,” as defined in Section 422 of the Code. Under the Code, an optionholder generally is not subject to ordinary income tax upon the grant or exercise of ISOs (although, in certain circumstances, there may be an item of adjustment included for alternative minimum tax purposes). If the optionholder holds a share received on exercise of an ISO for more than two years from the date the stock option was granted and more than one year from the date the stock option was exercised, which is referred to as the required holding period, the difference, if any, between the amount realized on a sale or other taxable disposition of that share and the holder’s tax basis in that share will be long-term capital gain or loss. If, however, an optionholder disposes of a share acquired on exercise of an ISO before the end of the required holding period, which is referred to as a disqualifying disposition, the optionholder generally will recognize ordinary income in the year of the disqualifying disposition equal to the excess, if any, of the fair market value of the share on the date the ISO was exercised over the exercise price.

We are not allowed an income tax deduction with respect to the grant or exercise of an ISO or the disposition of a share acquired on exercise of an ISO after the required holding period. If there is a disqualifying disposition of a share, however, we are generally allowed a deduction in an amount equal to the ordinary income includible in income by the optionholder.

Restricted Stock Awards and Stock Payment Awards

Generally, the recipient of a restricted stock award (including a stock payment award) will recognize ordinary income at the time the stock is received equal to the excess, if any, of the fair market value of the stock received over any amount paid by the recipient in exchange for the stock. If, however, the stock is not vested when it is received (for example, if the employee is required to work for a period of time in order to have the right to sell the stock), the recipient generally will not recognize income until the stock becomes vested, at which time the recipient will recognize ordinary income equal to the excess, if any, of the fair market value of the stock on the date it becomes vested over any amount paid by the recipient in exchange for the stock. A recipient may, however, file an election with the Internal Revenue Service, within 30 days following his or her receipt of the stock award, to recognize ordinary income, as of the date the recipient receives the award, equal to the excess, if any, of the fair market value of the stock on the date the award is granted over any amount paid by the recipient for the stock. We will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the recipient of the stock award.

Restricted Stock Unit Awards

Generally, the recipient of a stock unit structured to conform to the requirements of Section 409A of the Code or an exception to Section 409A of the Code will recognize ordinary income at the time the stock is delivered equal to the excess, if any, of the fair market value of the shares received over any amount paid by the recipient in exchange for the shares.

We will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the recipient of the stock award.

Stock Appreciation Rights

We may grant under the Amended 2024 Plan stock appreciation rights separate from any other award or in tandem with other awards under the Amended 2024 Plan.

Where the stock appreciation rights are granted with a strike price equal to the fair market value of the underlying stock on the grant date, the recipient will recognize ordinary income equal to the fair market value of the stock or cash received upon such exercise. We will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the recipient of the stock appreciation right.

Performance Awards

Any of the awards above may be granted with performance vesting conditions, and the tax treatment will be as set forth above, but with the fulfillment of the performance conditions being the vesting event.

Deferred Stock Awards and Deferred Stock Unit Awards

The tax treatment for deferred stock awards and deferred stock unit awards will be as set forth above for restricted stock awards and restricted stock unit awards, except that the taxable event will occur upon the satisfaction the deferral condition (other than with respect to employment taxes, which may be due in the year of vesting).

Dividend Equivalent Awards

Dividend Equivalent Awards will vest only when the underlying award vests, and will be subject to tax at the same time as the underlying award.

Section 162(m)

Under Section 162(m) of the Code (“Section 162(m)”), compensation paid to each of the Company’s “covered employees” that exceeds $1 million per taxable year is generally non-deductible. Although the Compensation Committee will continue to consider tax implications as one factor in determining executive compensation, the Compensation Committee also looks at other factors in making its decisions and retains the flexibility to provide compensation for the Company’s named executive officers in a manner consistent with the goals of our executive compensation program and the best interests of the Company and its stockholders, which may include providing for compensation that is not deductible by the Company.

Plan Benefits

The Company cannot currently determine the benefits or number of shares subject to awards that may be granted in the future to executive officers, directors, and employees under the Amended 2024 Plan. We do not presently have any current plans, proposals or arrangements, written or otherwise, to issue any of the newly available authorized shares under the Amended 2024 Plan, except as set forth below with respect to non-employee directors. As of March 31, 2025, we have approximately 159 employees, 5 consultants and 9 non-employee directors who would be eligible to receive grants under the Amended 2024 Plan. Awards granted under the Amended 2024 Plan to our non-employee directors are not subject to set benefits or amounts under the terms of the Amended 2024 Plan itself. However, our director compensation policy provides for certain equity award grants to our non-employee directors. On and after the date of the Annual Meeting, if this Proposal No. 4 is approved by our stockholders, any such equity award grants will be made under the Amended 2024 Plan. If this Proposal No. 4 is not approved by our stockholders, we will have insufficient shares under the 2024 Plan to make these grants. For additional information regarding our current compensation program for non-employee directors, please see information below in the section entitled “Non-Employee Director Compensation.”

Awards Granted under the 2024 Plan

The following table sets forth, for each of the individuals and various groups indicated, the total number of shares of our common stock subject to awards that have been granted under the 2024 Plan as of March 31, 2025.

Proposed Resolution

It is proposed that at the 2025 Annual Meeting the following resolution be adopted:

“RESOLVED, that the Adverum Biotechnologies, Inc. 2024 Equity Incentive Award Plan, as amended and restated, be, and hereby is, approved.”

Board of Directors’ Recommendation

OUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE “FOR” THE APPROVAL OF THE 2024 PLAN. IF NOT OTHERWISE SPECIFIED, PROXIES WILL BE VOTED “FOR” THE APPROVAL OF THIS PROPOSAL.

PROPOSAL NO. 5: APPROVAL OF AMENDMENT OF CERTAIN OUTSTANDING STOCK OPTIONS TO REDUCE THE EXERCISE PRICE PER SHARE TO THE CLOSING PRICE ON THE DATE OF REPRICING

Executive Summary

The vast majority of our outstanding stock options are substantially underwater due to our stock price decline and therefore do not currently provide meaningful retention or incentive value to our service providers, while nevertheless creating an overhang to our stockholders. As of March 31, 2025, approximately 4.9 million shares were the subject of outstanding options, of which approximately 3.9 million were underwater. In contrast to our stock price decline, the Company has made significant progress advancing the development of our lead program, Ixo-vec, during this same period and has added significant critical talent to its management team to support this progress. After considering a number of different alternatives with a goal of increasing the retentive value of our long-term incentive programs, we are asking the stockholders of the Company to authorize our Board to implement a one-time repricing of certain stock options.

General

To increase the long-term retention and incentive value of our options, we are asking the stockholders of the Company to authorize our Board to implement a one-time repricing of certain stock options to be implemented within 12 months following the date of this Annual Meeting. Any repricing would need to include the following key terms:

We believe it is in the best interests of the Company and our stockholders for this Proposal No. 5 to be approved.

On March 20, 2025, our Board approved, based on the Compensation Committee’s consideration and recommendation and subject to the approval of the stockholders at this Annual Meeting, the authority for the Board to implement the repricing of certain outstanding stock options (as described below, the “Eligible Options”), on a future date to be determined by the Board that falls within 12 months following the date of this Annual Meeting (such future date, the “Repricing Date”). An Eligible Option is a stock option that:

If this Proposal No. 5 is approved by our stockholders, and the Board decides to implement the repricing of Eligible Options, then on the Repricing Date, each then-outstanding Eligible Option will be amended to reduce its per-share exercise price to the closing price of our common stock on the Repricing Date (the “Repricing”). There will be no other changes to any Eligible Options as a result of the Repricing; except as described below under the heading “Potential Modification to Terms of the Repricing or Non-Implementation of Repricing.”

However, no holder of Eligible Options will benefit from the Repricing unless such holder remains in service with the Company through the Retention Period, as defined below under “Description of the Repricing.”

Reasons for Repricing

We have historically granted stock options and other equity-based awards under the Equity Plans because we believe that stock-based incentive compensation opportunities play a key role in our ability to recruit, motivate and retain qualified individuals. While our compensation packages include a number of different components, we believe that equity compensation effectively links pay to performance and aligns the interest of employees, consultants and directors with those of our stockholders by providing them with a means to benefit from increased stock value. We face significant competition for experienced and talented personnel with critical and high-demand skills in our industry, and stock options are an important part of our incentive compensation.

As a clinical-stage pharmaceutical company, the market price for our common stock has historically been volatile, reflecting the risks and uncertainties inherent in the development of our product candidates. In recent years, the market price of our common stock has been subject to material fluctuations, many of which were outside the control of our company and our employees and has declined from a five-year high of over $246.00 in June 2020 to approximately $4.37 on March 31, 2025.

In contrast to our stock price decline, the Company has made significant progress advancing the development of our lead program, Ixo-vec during this same period, including:

As a result of our stock price decline, as of March 31, 2025, a substantial number of our service providers who hold outstanding stock options are holding options that are substantially underwater. The weighted-average exercise price per share of options granted under our Equity Plans that are held by our service providers as of March 31, 2025, was $24.15 compared to a $4.37 closing price for our common stock on March 31, 2025. Of approximately 4.9 million outstanding stock options, approximately 3.9 million, or 80%, were underwater, and as such, do not currently provide meaningful retention or incentive value to our employees, directors and consultants, while nevertheless creating an overhang to our stockholders. Additionally, under applicable accounting rules, we are required to continue to recognize compensation expense related to these non-retentive options as they vest, even if they are never exercised because they remain underwater.

The table below sets forth certain information about the shares subject to options held by each of our NEOs; all executive officers, as a group; all directors who are not executive officers, as a group; and all employees who are not executive officers, as a group as of March 31, 2025: (i) the number of shares subject to options, (ii) the average per share exercise price of such options, (iii) the average remaining term in years of such options, and (iv) the number of such shares subject to options with exercise prices up to $10.14 per share (our 52-week intraday high at March 31, 2025), between $10.15 and $21.00 per share, and above $21.00 per share. The table omits time-based and performance-based full value awards.

Alternatives Considered

Beginning in April 2024, our Compensation Committee began to consider retention issues associated with our reduced stock price relative to the exercise prices of outstanding stock options. Our Compensation Committee engaged Aon’s Human Capital Solutions practice, a division of Aon plc (“Aon”), a national executive compensation consulting firm that regularly advises the Compensation Committee, to assist the Compensation Committee in evaluating issues associated with underwater stock options and in structuring a compensation program designed to retain and provide incentives to our employees, directors and consultants holding underwater options. Over the course of multiple meetings over the past twelve months, we have considered a number of alternatives with a goal of increasing the retentive value of our long-term incentive programs. In addition to the Repricing, we evaluated several other alternatives with Aon and our legal advisors:

Description of the Repricing

If the Board decides to implement the Repricing, then on the Repricing Date the Eligible Options will automatically be repriced to the closing price of our common stock on the Repricing Date. If any holder of an Eligible Option ceases to be a service provider of ours before the Repricing Date, their Eligible Options will not be repriced on the Repricing Date.

Any repricing of options held by a non-employee director will be reduced to the extent necessary so that the value of such repricing with respect to such director will not, in combination with other annual compensation provided to such director, exceed the applicable annual limit set forth in our non-employee director compensation policy ($150,000 as of March 31, 2025).

In order to exercise the Eligible Options at the reduced exercise price, participants will be required to remain in service with the Company through the end of the relevant Retention Period (as hereinafter defined). The “Retention

Period” begins on the Repricing Date and ends on the earliest of the following: (i) the date 12 months following the Repricing Date; (ii) a Change in Control (as defined in the 2024 Plan); and (iii) the Eligible Option holder’s Termination of Service (as defined in the 2024 Plan) due to such individual’s death or disability.

The following table summarizes information regarding the options granted under our Equity Plans that, as of March 31, 2025, were held by our service providers and the subset that were underwater based our 52-week intraday high of $10.14 on July 18, 2024:

The table below shows the potential payouts with or without a Repricing to each of our NEOs; all executive officers, as a group; all directors who are not executive officers, as a group; and all employees who are not executive officers, as a group based on option holdings as of March 31, 2025. The table sets forth the potential payouts at a range of stock prices for all options held by each of our NEOs in (i) the “no Repricing” scenario assuming no change in the strike price of any option and (ii) in “a Repricing” scenario as if the Repricing had happened on March 31, 2025 (i.e., assuming that options with strike prices above $10.14 per share, which is the 52-week intraday high as of March 31, 2025, were repriced at $4.37, our closing price on March 31, 2025) and that all options were held for 12 months following Repricing Date so that holders were able to exercise at the new strike price. The potential payout for an option is the difference between the assumed price ($10.00, $15.00 or $20.00) and the exercise price, multiplied by the number of shares subject to the option. The potential payout for an individual or group is calculated as the sum of potential payouts for all in-the-money options (based on the assumed price in the table) held by that individual or group at March 31, 2025. The table omits potential payouts associated with time-based and performance-based full value awards.

As of March 31, 2025, approximately 36% of the shares covered by these underwater options were vested. Note that the potential payouts assuming repricing of options in this table are calculated based on the options

that would be eligible for repricing based on the 52-week intraday high (for determining which options are Eligible Options) and the stock price (for determining the new strike price) as of March 31, 2025. If these assumed facts change, then the options eligible for repricing and the new strike price may change, which will also cause any potential payout amounts to change. In addition, this table assumes that the potential payout takes place after the Retention Period has been satisfied.

Potential Modification to Terms of the Repricing or Non-Implementation of Repricing

While the terms of the Repricing are expected to be materially similar to the terms described in this Proposal No. 5, the Compensation Committee, pursuant to the Board’s delegation of such authority to the Compensation Committee, may find it necessary or appropriate to impose further restrictions on the Eligible Shares or other terms of the Repricing to take into account factors such as administrative needs, legal and regulatory requirements, accounting rules and Company policy decisions; for clarity, any such change will not materially increase the benefits of the Repricing to any director, employee or consultant beyond the terms described in this Proposal No. 5. In addition, the Board may decide not to implement the Repricing even if our stockholders approve the Repricing.

U.S. Federal Income Tax Consequences

The following is a summary of the anticipated material U.S. federal income tax consequences of the Repricing. The applicable U.S. federal income tax law and regulations may change, and the U.S. Internal Revenue Service may adopt a position contrary to the summary below. All holders of Eligible Options are urged to consult their own tax advisers regarding the tax treatment of the Repricing under all applicable laws.

For purposes of the incentive stock option rules, the repricing of an Eligible Option that is an incentive stock option (an “Eligible ISO”) is treated as the grant of a new option on the Repricing Date. This means that if the holder of such Eligible Option is no longer an employee on the Repricing Date and has become a non-employee service provider, the repriced Eligible Option will not qualify as an incentive stock option and will instead be treated as a nonstatutory stock option.

If the holder of such Eligible Option is an employee of ours (or any parent or subsidiary of ours) on the Repricing Date, the repriced Eligible Option will be treated as an incentive stock option to the maximum extent permitted by law, but the holding periods applicable to the Eligible Option will restart on the Repricing Date for purposes of being subject to favorable tax treatment under the Code.

In addition, the Code limits the annual benefit an individual may receive from incentive stock options, preventing more than $100,000 worth of incentive stock options from becoming exercisable for the first time in any one calendar year. During the year in which a Repricing occurs, both the original option and the repriced option are counted towards this limit. To the extent the Repricing causes this limit to be exceeded, the excess portions of the repriced Eligible ISOs will be treated as nonstatutory stock options.

Below is a discussion of the U.S. federal tax treatment generally applicable to incentive stock options and nonstatutory stock options:

Incentive Stock Options. No taxable income is reportable when an incentive stock option is granted or exercised (except for purposes of the alternative minimum tax). If the holder exercises the option and then later sells or otherwise disposes of the shares more than two years after the grant date and more than one year after the exercise date, the difference between the sale price and the exercise price will be taxed as capital gain or loss. If the holder exercises the option and then later sells or otherwise disposes of the shares before the end of either of the two- or one-year holding periods described above, the holder generally will have ordinary income at the time of the sale equal to the fair market value of the shares on the exercise date (or the sale price, if less) minus the exercise price of the option.

Nonstatutory Stock Options. No taxable income is reportable when a nonstatutory stock option is granted with a per-share exercise price equal to the fair market value of the underlying stock on the date of grant. Upon exercise, the holder will recognize ordinary income in an amount equal to the excess of the fair market value (on the exercise date) of the shares purchased over the exercise price for those shares. Any taxable income recognized in connection with an option exercise by one of our employees is subject to tax withholding by us. Any additional gain or loss recognized upon any later disposition of the shares would be capital gain or loss to the holder.

Tax Effect on the Company. We generally will be entitled to a tax deduction in connection with the repriced Eligible Options in an amount equal to the ordinary income realized by the holder at the time the holder recognizes such income. Special rules limit the deductibility of compensation paid to our Chief Executive Officer and other “covered employees” within the meaning of Code Section 162(m). Under Code Section 162(m), the annual compensation paid to any of these specified employees will be deductible only to the extent that it does not exceed $1,000,000.

Financial Accounting Consequences

We account for share-based payments in accordance with Accounting Standards Codification Topic 718 (“ASC 718”), “Compensation-Stock Compensation.” Under ASC 718, we currently recognize and will continue to recognize compensation expense relating to underwater options until they vest, even though do not fully provide the intended incentive and retention benefits.

As a result of the Repricing, the extent as to which the fair value of each repriced Eligible Option immediately following the Repricing exceeds the fair value of the Eligible Option immediately before the Repricing will be considered incremental compensation under ASC 718. This excess, in addition to any remaining unrecognized expense for the repriced Eligible Options, will be recognized by us as an expense for compensation. This expense will be recognized ratably over the vesting period of the repriced Eligible Options in accordance with the requirements of ASC 718.

Interests of Certain Persons in the Repricing

The Eligible Options that will be repriced will be those held by individuals who remain our service providers through the Repricing Date. Each holder of an Eligible Option must continue to be a service provider of the Company through the Repricing Date in order to participate in the Repricing, and any such holder that terminates service with the Company before the Repricing Date will not have his or her Eligible Options repriced under the Repricing. As of March 31, 2025, a substantial number of our service providers who hold outstanding stock options are holding options a substantial portion of which are substantially underwater. Our directors and executive officers have an interest in this Proposal No. 5 because they hold options granted under our Equity Plans that may be Eligible Options. Please see tables in sections titled “Reasons for the Repricing” and “Description of the Repricing” in this Proposal No. 5 for more information about interest of the directors and executive officers in this Proposal No. 5.

Financial Statements

Our financial statements and other information required by Item 13(a) are incorporated by reference from our Annual Report on Form 10-K filed with the SEC on April 15, 2025.

Board of Directors’ Recommendation

THE BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE “FOR” THE APPROVAL OF THE REPRICING.

CORPORATE GOVERNANCE

Code of Business Conduct and Ethics

We have adopted a Code of Business Conduct and Ethics that applies to all of our employees, officers and directors, including those officers responsible for financial reporting. The Code of Business Conduct and Ethics is publicly available on our website at http://investors.adverum.com/governance/. We intend to promptly disclose on our website or in a Current Report on Form 8-K in the future (i) the date and nature of any amendment (other than technical, administrative or other non-substantive amendments) to the Code of Business Conduct and Ethics that applies to our principal executive officer, principal financial officer, principal accounting officer or controller or persons performing similar functions and relates to any element of the code of ethics definition enumerated in Item 406(b) of Regulation S-K and (ii) the nature of any waiver, including an implicit waiver, from a provision of the Code of Business Conduct and Ethics that is granted to one of these specified individuals that relates to one or more of the elements of the code of ethics definition enumerated in Item 406(b) of Regulation S-K, the name of such person who is granted the waiver and the date of the waiver.

We have adopted insider trading policies and procedures governing the purchase, sale, and/or other dispositions of our securities by directors, officers and employees. A copy of the insider trading policy is filed as an exhibit to our Annual Report on Form 10-K for the year ended December 31, 2024. In addition, it is the Company’s intent to comply with the applicable laws and regulations relating to insider trading.

Corporate Governance Guidelines

We believe in sound corporate governance practices and have adopted formal Corporate Governance Guidelines to enhance our effectiveness. Our Board adopted these Corporate Governance Guidelines to ensure that it has the necessary practices in place to review and evaluate our business operations as needed and to make decisions that are independent of our management. The Corporate Governance Guidelines are also intended to align the interests of our directors and management with those of our stockholders. The Corporate Governance Guidelines set forth the practices our Board follows with respect to Board and committee composition and selection, board meetings, Chief Executive Officer performance evaluation and management development and succession planning for senior management, including the Chief Executive Officer position. A copy of our Corporate Governance Guidelines is available on our website at http://investors.adverum.com/governance/.

Board Composition

Director Independence

Our common stock is listed on The Nasdaq Capital Market. Rule 5605 of the Marketplace Rules of the Nasdaq Stock Market LLC (the “Nasdaq Listing Rules”) requires that independent directors compose a majority of a listed company’s board of directors within one year of listing. In addition, the Nasdaq Listing Rules require that, subject to specified exceptions, each member of a listed company’s audit and compensation committees be independent and that audit committee members also satisfy independence criteria set forth in Rule 10A-3 under the Exchange Act. Under Nasdaq Listing Rule 5605(a)(2), a director will only qualify as an “independent director” if, in the opinion of the 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. Nasdaq Listing Rule 5605(a)(2) also specifies certain categories of persons who will not be considered independent, including employees, family members of executive officers and recipients of compensation from the company in excess of $120,000 during any period of twelve consecutive months within the past three years, subject to certain exceptions. 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: (1) accept, directly or indirectly, any consulting, advisory, or other compensatory fee from the listed company or any of its subsidiaries; or (2) be an affiliated person of the listed company or any of its subsidiaries. In addition to satisfying general independence requirements under the Nasdaq Listing Rules, members of the compensation committee must also satisfy additional independence requirements set forth in Nasdaq Listing Rule 5605(d)(2). To be considered independent for purposes of Nasdaq Listing Rule 5605(d)(2), our Board must consider all factors specifically relevant to

determining whether a director has a relationship with us 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 such director, including any consulting, advisory or other compensatory fee paid by us to such director; and whether such director is affiliated with us, a subsidiary of our company or an affiliate of a subsidiary of our company.

In March 2025, our Board undertook a review of 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 each of Ms. Hong, Dr. Lupher, Mr. Machado, Dr. Nicholson, Mr. Scopa, Ms. Svoronos, Dr. Tuckson, and Dr. Whitcup is independent within the meaning of Rule 5605 of the Nasdaq Listing Rules. Our Board also determined that Mr. Machado, Mr. Scopa, and Ms. Svoronos, who compose our Audit Committee, and Ms. Hong, Mr. Machado, Mr. Scopa, and Dr. Tuckson, who compose our Compensation Committee, satisfy the independence standards for those committees established by applicable SEC rules and Nasdaq Listing Rules. In making these determinations, our Board considered the current and prior relationships that each non-employee director has with our company and all other facts and circumstances our Board of Directors deemed relevant in determining their independence. For example, the Board considered (i) with respect to Mr. Machado and Ms. Svoronos, the fact that both Mr. Machado and Ms. Svoronos serve on the board of directors of ACELYRIN, INC. and Xenon Pharmaceuticals, Inc. and (ii) with respect to Dr. Tuckson, the fact that both Dr. Tuckson and Dr. Fischer previously served on the board of directors of CTI Biopharma Corp.

Classified Board of Directors

In accordance with our amended and restated certificate of incorporation, our Board is divided into three classes with staggered three-year terms. At each annual meeting of stockholders, the successors to directors whose terms then expire will be elected to serve from the time of election and qualification until the third annual meeting following their election.

We feel strongly that, given the long runway for drug therapy development and given the stage and size of the Adverum, a classified Board is appropriate at the current time.

Leadership Structure of our Board

Our amended and restated Bylaws and Corporate Governance Guidelines provide our Board with flexibility to combine or separate the positions of Chair of the Board and Chief Executive Officer and/or appoint a lead director in accordance with its determination that utilizing one or the other structure would be in the best interests of our company. The roles of Chair of the Board and Chief Executive Officer are currently filled by Mr. Machado and Dr. Fischer, respectively. While the positions of Chief Executive Officer and Chair of the Board are currently held by different individuals, we do not believe there should be a fixed rule regarding the separation of these positions, or whether the chair should be an employee of ours or should be elected from among the non-employee directors. Our needs and the individuals available to assume these roles may require different outcomes at different times, and we and our Board believe that retaining that flexibility in these decisions is in our best interests. See “Role of Board in Risk Oversight Process” for a discussion on how our Board manages risk.

Mr. Machado has served as Chair of the Board since May 2019. Mr. Machado’s tenure on the Board, his experience in serving on multiple other biotechnology company boards, as well as the deep knowledge of our company gained in his role as a member of the Audit Committee of the Board, allow him to provide valuable insights and facilitate the implementation of our strategic initiatives and business plans. In our view, having a Chair that is far removed from management would have the potential to give rise to divided leadership, which could interfere with good decision making or weaken our ability to develop and implement strategy. The Board also believes, however, that Mr. Machado’s independence is an essential complement to his familiarity with our company and management representation on the Board, helping to foster an environment that is conducive to objective evaluation and oversight of management’s performance.

Board Qualifications

The Nominating and Corporate Governance Committee is responsible for reviewing with the Board, on an annual basis, the appropriate characteristics, skills and experience required for the Board as a whole and its individual members. In evaluating the suitability of individual candidates (both new candidates and current Board

members), the Nominating and Corporate Governance Committee, in recommending candidates for election, and the Board, in approving (and, in the case of vacancies, appointing) such candidates, may take into account many factors, including: personal and professional integrity, ethics and values; experience in corporate management, such as serving as an officer or former officer of a publicly held company; strong finance experience; experience relevant to our industry; experience as a director or executive officer of another publicly held company; diversity of expertise and experience in substantive matters pertaining to our business relative to other Board members; diversity of background and perspective; and practical and mature business judgment, including the ability to make independent analytical inquiries. The Board believes that diversity of viewpoints, background, experience and other characteristics are an important part of its makeup, and it actively seeks these characteristics in identifying director candidates. The Board evaluates each individual in the context of the Board as a whole, with the objective of assembling a group that can best perpetuate the success of the business and represent stockholder interests through the exercise of sound judgment using its diversity of experience in these various areas. In addition, the Board evaluates each individual’s other professional commitments against their personal capacity to ensure they have adequate time and flexibility to execute their Board duties.

The Nominating and Corporate Governance Committee considers diversity in identifying director nominees, striving to nominate directors with a variety of individual backgrounds and complementary skills so that, as a group, the Board will possess the appropriate talent, skills and expertise to oversee Adverum’s business and operations.

In searching for qualified director candidates to fill vacancies in the Board, the Nominating and Corporate Governance Committee solicits our Board for names of potentially qualified candidates. Additionally, the Nominating and Corporate Governance Committee may request that members of the Board pursue their own business contacts for the names of potentially qualified candidates. The Nominating and Corporate Governance Committee then considers the potential pool of director candidates, selects the candidate the committee believes best meets the then-current needs of the Board, and conducts a thorough investigation of the proposed candidate’s background to ensure there is no past history that would cause the candidate not to be qualified to serve as a member of our Board.

To fulfill its responsibility to recruit and recommend to the Board nominees for election as directors, the Nominating and Corporate Governance Committee considers all qualified candidates who may be identified by any one of the following sources: current or former Board members, a professional search firm, Adverum executives or stockholders.

Stockholders who wish to make a recommendation or propose a director candidate for consideration by the Nominating and Governance Committee may do so by submitting the candidate’s name, resume and biographical information and qualifications to the attention of the Corporate Secretary, Adverum Biotechnologies, Inc., 100 Cardinal Way, Redwood City, California 94063. All recommendations received by the Corporate Secretary will be presented to the Nominating and Governance Committee for its consideration.

We may request from the nominating stockholder or nominating stockholder group such other information as may reasonably be required to determine whether each person recommended by a stockholder or stockholder group as a nominee meets any minimum requirements that may be established by our Board and to enable us to make appropriate disclosures to stockholders entitled to vote in the next election of directors. Proposed nominees are required to make themselves reasonably available to be interviewed by the Nominating and Corporate Governance Committee and members of management, as determined to be appropriate by the Nominating and Corporate Governance Committee. We will not accept a stockholder recommendation for a nominee if the recommended candidate’s candidacy or, if elected, Board membership, would violate applicable state law, federal law or the rules of any exchange or market on which our securities are listed or traded. If the proposed nomination by stockholders was made in accordance with the procedures in our amended and restated bylaws, the Nominating and Corporate Governance Committee will apply the same criteria in evaluating the proposed nominee as it would any other Board nominee candidate and will recommend to our Board whether or not the proposed stockholder nominee should be nominated by our Board and included in our proxy statement.

Stockholders who wish to nominate a director for election at an upcoming annual meeting of stockholders must comply with the advance notice provisions in our amended and restated bylaws. Each stockholder making a nomination is required to provide certain information, representations and undertakings as outlined in our amended and restated bylaws. The Nominating and Corporate Governance Committee will consider director

candidates recommended by our stockholders. If a stockholder submits a proposed nominee, the Nominating and Corporate Governance Committee will consider the proposed nominee, along with any other proposed nominees recommended by members of the Board, in the same manner in which the Nominating and Corporate Governance Committee would evaluate its nominees for director. For a description of the proper procedure for stockholder nominations, see “Procedures for Nomination of Directors by Stockholders” in this proxy statement.

Role of Board in Risk Oversight Process

We are exposed to a number of risks, including economic, environmental, operational, and regulatory risks, among others. Risk assessment and oversight are an integral part of our governance and management processes. Our Board encourages management to promote a culture that incorporates risk management into our corporate strategy and day-to-day business operations. Management discusses strategic and operational risks at regular management meetings, and conducts specific strategic planning and review sessions during the year that include a focused discussion and analysis of the risks facing us. Throughout the year, senior management reviews these risks with our Board at regular meetings as part of management presentations that focus on particular business functions, operations or strategies, and presents the steps taken by management to mitigate or eliminate such risks.

Our Board does not have a standing risk management committee, but rather administers this oversight function directly through our Board as a whole, as well as through various standing committees of our Board that address risks inherent in their respective areas of oversight. In particular, our Board is responsible for monitoring and assessing strategic risk exposure and key enterprise risks, and our Audit Committee is responsible for overseeing our major financial risk exposures and the steps our management has taken to monitor and control these exposures. The Audit Committee also monitors compliance with legal and regulatory requirements. Our Nominating and Corporate Governance Committee monitors the effectiveness of our corporate governance guidelines. Our Compensation Committee assesses and monitors whether any of our compensation policies and programs has the potential to encourage excessive risk-taking. The Board or appropriate Board committees discuss selected risks in more detail throughout the year.

Board Committees

Our Board has three primary committees: the Audit Committee, the Compensation Committee and the Nominating and Corporate Governance Committee, which are described below. In addition, the Board has a Research and Development Committee.

Audit Committee

Our Audit Committee oversees our corporate accounting and financial reporting process. Among other matters, the Audit Committee:

The current members of our Audit Committee are Mr. Machado (Chair), Mr. Scopa and Ms. Svoronos. 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. Machado is an Audit Committee financial expert as defined under the applicable rules of the SEC and has the requisite financial sophistication as defined under the Nasdaq Listing Rules.

The Audit Committee operates under a written charter that satisfies the applicable rules and regulation of the SEC and the Nasdaq Listing Rules. A copy of the Audit Committee charter is available on our website at http://investors.adverum.com/governance/.

Compensation Committee

Our Compensation Committee reviews and approves, or may recommend to the full Board or independent members of the Board, as applicable, policies relating to compensation and benefits of our officers, directors and employees. The Compensation Committee reviews and approves corporate goals and objectives relevant to compensation of our Chief Executive Officer and other executive officers, evaluates the performance of these officers in light of those goals and objectives, and sets or makes recommendations to our Board regarding the compensation of these officers based on such evaluations. Our Board retains the authority to determine and approve, upon the recommendation of the Compensation Committee, the compensation of the Chief Executive Officer, unless such authority has been delegated to the Compensation Committee. The Compensation Committee also approves grants of stock options and other awards under our stock plans. In fulfilling its responsibilities, the Compensation Committee may delegate any or all of its responsibilities to a subcommittee of the Compensation Committee, but only to the extent consistent with our amended and restated certificate of incorporation, amended and restated bylaws, applicable Nasdaq Listing Rules, and other applicable law. The Compensation Committee will periodically review and evaluate the performance of the Compensation Committee and its members, including an annual review of its charter. The current members of our Compensation Committee are Mr. Scopa (Chair), Ms. Hong, Mr. Machado and Dr. Tuckson.

Each of the current members of our Compensation Committee is independent under the Nasdaq Listing Rules and regulations and is a “non-employee director” as defined in Rule 16b-3 promulgated under the Exchange Act.

Since 2019, Aon, a national executive compensation consulting firm, has been engaged by the Compensation Committee to conduct market research and analysis to assist the Compensation Committee in developing appropriate compensation and incentives for our executive officers, to advise the Compensation Committee and provide ongoing recommendations regarding material executive compensation decisions, to review compensation proposals from management, and prepare an assessment of our non-employee director compensation program. Aon reports directly to the Compensation Committee and does not provide any non-compensation-related services to us. After review and consultation with Aon, the Compensation Committee determined that Aon is independent and that there is no conflict of interest resulting from retaining Aon. In reaching these conclusions, our Compensation Committee considered the factors set forth in SEC rules and the Nasdaq Listing Rules.

Our executive officers submit proposals to our Board and Compensation Committee regarding our executive and director compensation. Our Chief Executive Officer provides feedback and recommendations to our Compensation Committee with respect to executive compensation, other than his own compensation, including with regard to senior executive performance, responsibility and experience levels. The Compensation Committee often takes into consideration both our Chief Executive Officer’s input and the input of other senior executives in setting compensation levels.

The Compensation Committee operates under a written charter that satisfies the applicable rules and regulations of the SEC and the Nasdaq Listing Rules. A copy of the Compensation Committee charter is available on our website at http://investors.adverum.com/governance/.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee is responsible for making recommendations to our Board regarding candidates for directorships and composition and organization of our Board. In addition, the Nominating and Corporate Governance Committee is responsible for overseeing our corporate governance policies and reporting and making recommendations to our Board concerning governance matters. The current

members of our Nominating and Corporate Governance Committee are Ms. Svoronos (Chair), Dr. Lupher, Dr. Tuckson and Dr. Whitcup. Each of the members of our Nominating and Corporate Governance Committee is an independent director under the Nasdaq Listing Rules.

The Nominating and Corporate Governance Committee operates under a written charter. A copy of the Nominating and Corporate Governance Committee charter is available on our website at http://investors.adverum.com/governance/.

Research and Development Committee

The Research and Development Committee is responsible for overseeing Adverum’s research and development programs, strategy and opportunities. The current members of our Research and Development Committee are Drs. Whitcup (Chair), Kiss, Lupher, and Nicholson.

Meetings of the Board of Directors and Committees

During 2024, our Board met four times, the Audit Committee met nine times, the Compensation Committee met eight times, the Nominating and Corporate Governance Committee met five times and the Research and Development Committee met twice. In 2024, each director attended at least 75% of the meetings of our Board and the committees on which the director served that were held while the person was a member of the applicable committee.

Limitation on Liability and Indemnification Matters

Our amended and restated certificate of incorporation contains provisions that limit the liability of our directors for monetary damages to the fullest extent permitted by Delaware law. Consequently, our directors will not be personally liable to us or our stockholders for monetary damages for any breach of fiduciary duties as directors, except liability for:

Our amended and restated certificate of incorporation and amended and restated bylaws provide that we are required to indemnify our directors and officers, in each case to the fullest extent permitted by Delaware law. Our amended and restated bylaws also provide that we are obligated to advance expenses incurred by a director or officer in advance of the final disposition of any action or proceeding, and permit us to secure insurance on behalf of any officer, director, employee or other agent for any liability arising out of his or her actions in that capacity regardless of whether we would otherwise be permitted to indemnify him or her under Delaware law. We have entered, and expect to continue to enter, into agreements to indemnify our directors, executive officers and other employees as determined by our Board. We have entered into an indemnification agreement with each of our directors, including each of our Board’s nominees for director. With specified exceptions, these agreements provide for indemnification for related expenses, including, among other things, attorneys’ fees, judgments, fines and settlement amounts incurred by any of these individuals in any action or proceeding. We believe that these bylaw provisions and indemnification agreements are necessary to attract and retain qualified persons as directors and officers. We also maintain directors’ and officers’ liability insurance.

The limitation of liability and indemnification provisions in our amended and restated certificate of incorporation and amended and restated bylaws may discourage stockholders from bringing a lawsuit against our directors and officers for breach of their fiduciary duty. They may also reduce the likelihood of derivative litigation against our directors and officers, even though an action, if successful, might benefit us and our stockholders. Further, a stockholder’s investment may be adversely affected to the extent that we pay the costs of settlement and damages. To the extent the indemnification for liabilities arising under the Securities Act may be permitted to our directors, officers and controlling persons pursuant to the foregoing provisions, or otherwise, we have been advised that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

Director Attendance at Annual Meetings

Although our directors are encouraged to attend our annual meetings, attendance is not mandatory. All of our then current directors attended the 2024 Annual Meeting of Stockholders. Our Board and management team encourage all of our directors to attend the virtual 2025 Annual Meeting.

Stockholder Communications with the Board of Directors

We provide a process for stockholders to send communications to our Board, the non-employee members of the Board as a group or any of the directors individually. Stockholders may contact any of the directors, including the non-employee directors, by writing to them c/o the Corporate Secretary, Adverum Biotechnologies, Inc., 100 Cardinal Way, Redwood City, California 94063. All appropriate communications will be compiled by our Corporate Secretary and submitted to our Board or individual directors, as applicable, on a periodic basis.

Procedures for Nomination of Directors by Stockholders

Stockholders who wish to nominate a director for election at an upcoming annual meeting of stockholders must comply with the advance notice provisions in our amended and restated bylaws. Each stockholder making a nomination is required to provide certain information, representations and undertakings as outlined in our amended and restated bylaws.

We may request from the nominating stockholder or nominating stockholder group such other information as may reasonably be required to determine whether each person proposed to be nominated by a stockholder or stockholder group meets any minimum requirements that may be established by our Board and to enable us to make appropriate disclosures to stockholders entitled to vote in the next election of directors. Proposed nominees are required to make themselves reasonably available to be interviewed by the Nominating and Corporate Governance Committee and members of management, as determined to be appropriate by the Nominating and Corporate Governance Committee. We will not accept a stockholder nomination if the nominee’s candidacy or, if elected, Board membership would violate applicable state law, federal law or the rules of any exchange or market on which our securities are listed or traded. If the proposed nomination by stockholders was made in accordance with the procedures in our bylaws, the Nominating and Corporate Governance Committee will apply the same criteria in evaluating the proposed nominee as it would any other Board nominee candidate and will recommend to our Board whether or not the proposed stockholder nominee should be nominated by our Board and included in our proxy statement.

Notices of nominations must be received only during the period specified above under “When are stockholder proposals due for next year’s annual meeting?” in the section “Questions and Answers about the 2025 Annual Meeting.”

Compensation Committee Interlocks and Insider Participation

None of the members of our Compensation Committee is, or has ever been, an executive officer or employee of the Company.

None of our executive officers currently serves, or in the last completed year has served, as a member of the board or compensation committee, or other committee serving an equivalent function, of any entity that has one or more executive officers who serve as members of our Board or our Compensation Committee.

Prohibition on Hedging and Pledging

Our insider trading policy, which applies to all of our officers, directors, and employees, prohibits hedging and monetization transactions, such as zero-cost collars and forward sale contracts, that allow individuals to continue to own the covered securities but without the full risks of ownership. Margin purchases, holding securities in a “margin account,” and pledging our securities as collateral to secure loans is also prohibited.

Environmental and Social Responsibility

At Adverum, our values define how we conduct business, shape patient care, apply science to medicine, and work and grow as a company with a goal of ensuring long-term performance. We strive to put our corporate values into action every day by reducing the environmental impact of our research and operations, providing safe, engaging and impactful work for our employees, and always leading with integrity to achieve business objectives.

Our Core Values

We integrate environmental, social, and governance objectives into our decision-making with the goal of delivering long-term value to all of our stakeholders. Our leadership creates and monitors our sustainability-related programs, with our Board maintaining ultimate oversight.

To identify the sustainability issues material to our business, we are guided by best practices, feedback we receive from our stakeholders, including employees, regulators, patients and investors, and third-party thought leaders, such as the Sustainability Accounting Standards Board (SASB), Biotechnology and Pharmaceuticals.

Additional information regarding Adverum’s environmental and social practices is included in the “Sustainability” subsection of the “Company” section of our website. Information on our website is not incorporated by reference in this proxy statement.

NON-EMPLOYEE DIRECTOR COMPENSATION

Overview

The Compensation Committee reviews pay levels for non-employee directors periodically with assistance from its compensation consultant, Aon, which prepares a comprehensive assessment of our non-employee director compensation program. That assessment includes benchmarking of director compensation against the same peer group used for executive compensation purposes, an update on recent trends in director compensation and a review of related corporate governance best practices. For further information regarding our peer group, please see the section below titled “Compensation Discussion and Analysis - Competitive Market Pay Information,” and in particular the discussion of the 2024 Peer Group, as defined in that section. Following that review, either the Compensation Committee or the Board, consistent with the recommendation of the Compensation Committee, determines the non-employee director compensation program that will be in effect until the next such determination.

Non-Employee Director Compensation Policy

In May 2024, Aon reviewed our director compensation program, indicated that the cash portion of our program was market competitive and approximately positioned at the 75^th percentile of the peer group and recommended that it remain unchanged from the prior year. As such no changes were made to the cash portion of the program. Under our non-employee director compensation policy, each non-employee director receives the following cash compensation for Board and standing committee service, as applicable:

Annual cash retainers for service as a non-employee Chair of our Board, chair of a committee or non-chair member of the committee are in addition to the annual cash retainer for service as a Board member. Cash retainers are prorated for any partial years of service. We also reimburse our non-employee directors for their reasonable out-of-pocket expenses incurred in attending Board and committee meetings.

On May 22, 2024, the Compensation Committee approved the amendment and restatement of the company’s non-employee director compensation policy (“Amended Non-Employee Director Compensation Policy”), which includes the following limits to be in effect for three years: (i) a $150,000 cap on non-employee director annual compensation while our market capitalization is below $250 million, (ii) a $250,000 cap on non-employee director annual compensation while our market capitalization is greater than $250 million and less than $500 million, (iii) a $400,000 cap on non-employee director annual compensation while our market capitalization is greater than $500 million and less than $1 billion, (iv) a $475,000 cap on non-employee director annual compensation while our market capitalization is greater than $1 billion, (v) a limit on the grant date fair value of one-time stock option grants made to new directors (which reflects two times the grant date fair value of the annual stock option grant made to continuing non-employee directors) and (vi) an additional stock option grant to the Chair of the Board equal to 30% of the value of the annual option grant award.

Option Awards

In May 2024, as part of its review of our director compensation program, Aon indicated that the equity award component of the 2023 program was positioned between the 25^th and 50^th percentile of the peer group from a value delivered perspective and at the 25^th percentile for purposes of dilution delivered, and most peers, like Adverum, utilized stock options as the form of equity award for the director compensation program. Aon recommended that equity compensation continue to be delivered in the form of stock options, and that the grant size should be adjusted to target the 50^th percentile on a dilution basis and that this, when coupled with the cash portion of the program, would remain below the limits set forth in the Amended Non-Employee Director Compensation Policy, as described above.

As such, pursuant to our Amended Non-Employee Director Compensation Policy, the non-employee directors receive grants of non-statutory stock options under our 2024 Plan. Each person who first becomes a non-employee director, whether through election by the stockholders of the Company or appointment by the Board to fill a vacancy, will be granted a nonstatutory stock option to purchase a number of shares of common stock having an option value of 200% of the option value of the most recent annual director options granted (an “Initial Option”), which grant will be made on or about the date of his or her initial election or appointment to be a non-employee director. On or about the date of each annual meeting of the Company’s stockholders, (i) each person who is then a non-employee director and will be continuing as a non-employee director following the date of such annual meeting (other than any non-employee director receiving an Initial Option on the date of such annual meeting or who has received an Initial Option within the same calendar year as such annual meeting) will be granted a nonstatutory stock option to purchase a number of shares of common stock having an option value represented by the number of shares approximately equal to the median annual equity award (as a percent of company) granted to non-employee directors of the Company’s peer group as applied to the number of shares of the Company’s stock outstanding as of the date of the grant, provided that the value of the option grant should not exceed the applicable annual compensation limit less the maximum annual cash compensation (a “Board Annual Award”) and (ii) the Chair of the Board will be granted an additional nonstatutory stock option to purchase a number of shares of our common stock with an option value equal to approximately 30% of the value of the Board Annual Award (a “Chair Additional Annual Award”).

Each Initial Option vests ratably in annual installments over three years of service following the date of grant, subject to continued service of the director through each such vesting date, provided, however, that the vesting will accelerate and the Initial Option will become fully vested and exercisable upon the consummation of a change in control. The Board Annual Awards and Chair Additional Annual Awards vest in full on the earlier to occur of the first anniversary of the grant date or the next annual meeting, subject to continued service of the director through such vesting date, provided, however, that the vesting will accelerate and the Board Annual Awards and Chair Additional Annual Awards will become fully vested and exercisable upon the consummation of a change in control. All such options have a maximum term of ten years.

Total Non-Employee Director Compensation

The following table presents the total compensation for each person who served as a non-employee member of our Board during the year ended December 31, 2024. Dr. Fischer’s compensation as a named executive officer is set forth under the Summary Compensation Table. Dr. Ozden was appointed as the Company’s Chief Medical Officer on June 10, 2024. At such time, she ceased serving as a non-employee director. For this reason, Dr. Ozden’s compensation for the portion of the year that she served as a non-employee director is not included in the below table and is instead reflected in the “All Other Compensation” column of the Summary Compensation Table.

CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS

Except as set forth below, we had no transactions that have occurred since January 1, 2023 and to which we were a party, in which the amount involved exceeded the lesser of $120,000 and 1% of the average of our total assets at year-end for the last two completed fiscal years and in which any of our directors, executive officers or holders of more than 5% of our capital stock, or an affiliate or immediate family member thereof, at any time from January 1, 2023 to the date of this report, had or will have a direct or indirect material interest, other than those already described in this proxy statement under the headings “Non-Employee Director Compensation” and “Executive Compensation.”

Consulting Agreement with FLG Partners

In November 2022, we entered into a consulting agreement with FLG Partners, LLC (“FLG Partners”), pursuant to which FLG Partners provided us with consulting services. Pursuant to the consulting agreement, Linda Rubinstein has served as our Chief Financial Officer from December 2022 to August 2023. In 2023, we paid FLG Partners $674,863 for consulting services under the consulting agreement, including for the services of Ms. Rubinstein. Concurrent with Ms. Rubinstein’s acceptance of and conversion to full time employment with the Company in August 2023, the consulting agreement with FLG Partners was mutually terminated by the Company and FLG Partners.

Consulting Agreement with Richard Beckman, M.D.

In May 2023, we entered into a consulting agreement with Dr. Beckman, effective June 1, 2023. Pursuant to the consulting agreement, for an initial term of twelve months (the “Initial Term”), Dr. Beckman provided up to 40 hours per month of consulting services to Adverum for consideration of $42,083 per month, with any additional services in excess of 40 hours per month compensated at a rate of $600 per hour. In 2023, we paid an aggregate of $339,383 to Dr. Beckman pursuant to the consulting agreement. Adverum also paid COBRA premiums for Dr. Beckman and his covered dependents during the Initial Term. Following the Initial Term, the consulting agreement may be renewed on a monthly basis, during which time Dr. Beckman will provide consulting services on an hourly basis for compensation of $600 per hour. Dr. Beckman’s equity awards with Adverum shall continue to vest during the term of the consulting agreement. Under the first amendment to the consulting agreement, Dr. Beckman’s equity awards ceased vesting as of the end of the Initial Term. The consulting agreement also provides that, the post-termination exercise period of Dr. Beckman’s vested stock options as of the termination date of the consulting agreement shall be extended to the date that is twelve months from the last day of the term of the consulting agreement.

Employment Agreement with Sareh Seyedkazemi

Dr. Sareh Seyedkazemi, our Director of Clinical Affairs, is the sister of Dr. Setareh Seyedkazemi, our Chief Development Officer. In 2024, total compensation paid to Dr. Sareh Seyedkazemi (including consulting fees paid to a third-party firm for Dr. Sareh Seyedkazemi’s services, base salary and cash bonus) was $143,806. From January 1, 2025 through March 31, 2025, total compensation paid to Dr. Sareh Seyedkazemi (consisting of base salary) was $79,204. Dr. Seyedkazemi additionally participates in the Company’s standard benefits programs. The compensation paid to Dr. Sareh Seyedkazemi was approved in accordance with our standard compensation practices for similarly situated employees.

February 2024 Private Placements

On February 7, 2024, we issued and sold to certain institutional and accredited investors (the “Investors”) in a private placement (the “Private Placement”) an aggregate of 10,550,005 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share, and to certain investors, in lieu of Shares, pre-funded warrants (the “Pre-Funded Warrants”) to purchase an aggregate of 75,000 shares of common stock. The purchase price per Share was $12.00 (or $11.999 per Pre-Funded Warrant, which represents the purchase price per Share to be sold in the Private Placement, minus the $0.0001 per share exercise price of each such Pre-Funded Warrant). Existing investors that previously held five percent or more of the Company’s outstanding common stock, including Commodore Capital LP, FMR LLC and Venrock Healthcare Capital Partners III, L.P., and/or their affiliates, purchased approximately $7.0 million, $10.0 million and $12.5 million, respectively, in Shares in the Private Placement.

Concurrently with the Private Placement, Mark Lupher, Ph.D., and James Scopa, directors of the Company, also purchased approximately $175,500 and $135,000, respectively, of shares of common stock in a private placement at a price per share of $13.50, on otherwise substantially the same terms as the Private Placement.

Policies and Procedures for Related Party Transactions

Our Board has adopted a written related person transaction policy to set forth the policies and procedures for the review and approval or ratification of related person transactions. This policy covers, with certain exceptions set forth in Item 404 of Regulation S-K, any transaction, arrangement or relationship, or any series of similar transactions, arrangements or relationships in which we were or are to be a participant, where the amount involved exceeds $120,000 and a related person had, has or will have a direct or indirect material interest, including, without limitation, purchases of goods or services by or from the related person or entities in which the related person has a material interest, indebtedness and guarantees of indebtedness.

As provided by our related party transaction policy, our Audit Committee will be responsible for reviewing and approving in advance the related person transaction and in doing so will consider all relevant facts and circumstances, including, but not limited to, whether the transaction is on terms comparable to those that could be obtained in an arm’s-length transaction and the extent of the related person’s interest in the transaction.

EXECUTIVE OFFICERS

Our executive officers are appointed by and serve at the discretion of the Board. There are no family relationships among our directors and executive officers. The following table provides information regarding our executive officers, including their ages and positions, as of March 31, 2025:

A brief biography of each of our executive officers appears below, except for Dr. Fischer, whose biographical information appears above under “Class II Directors” above.

Linda Rubinstein Ms. Rubinstein has served as our chief financial officer since December 2022. Since September 2010, Ms. Rubinstein has served as partner at FLG Partners, LLC (“FLG”), a chief financial officer and board advisory services firm, where she assists clients with strategic planning, executes financing transactions, creates business plans and develops corporate and investor positioning. Through FLG, Ms. Rubinstein has served as chief financial officer, consulting chief financial officer or financial advisor to multiple biotechnology companies, including Alector, Inc., Apexigen, Inc., ArmaGen, Inc., Five Prime Therapeutics, Inc., iPierian, Inc., Kezar Life Sciences, Inc., Medikine, Inc., RenovoRx, Inc., Sublimity Therapeutics Holdings Ltd., True North Therapeutics, Inc. and Tunitas Therapeutics, Inc. Ms. Rubinstein also served as the chief financial officer of PaxVax, Inc. from February 2014 to October 2014, of Ingenuity Systems, Inc. from October 2010 until its acquisition by QIAGEN N.V. in April 2013 and of Solexa, Inc. from March 2005 until its acquisition by Illumina, Inc. in January 2007 and as principal of RDJ Advisors from April 2007 to September 2010. In addition, Ms. Rubinstein previously served on the board of directors of Biocept, Inc. from July 2021 to October 2023. Ms. Rubinstein received a B.A. and an M.A. from the University of California, Los Angeles.

Rabia Gurses Ozden, M.D. Dr. Ozden has served as our chief medical officer since June 2024. Dr. Ozden previously served as a member of our Board of Directors from March 2022 to June 2024. Dr. Ozden has over 20 years of ophthalmology drug development experience, including extensive experience in AAV-based ophthalmic gene therapies. Most recently, Dr. Ozden served as chief medical officer at Ocular Therapeutix, Inc., an ophthalmic biopharmaceutical company, from July 2022 to June 2024 and prior to that was Ocular’s senior vice president, clinical development, from January 2021 to June 2022. Prior to joining Ocular, Dr. Ozden served as the chief development officer at Akouos, Inc., a precision genetic medicine company, from September 2019 to January 2021. From January 2019 to August 2019, Dr. Ozden served as the chief medical officer of Nightstar Therapeutics plc. (acquired by Biogen in 2019), a clinical-stage gene therapy company. Prior to Nightstar, from March 2018 to May 2019, Dr. Ozden consulted at Clementia Pharmaceuticals Inc. From July 2015 to March 2018, Dr. Ozden was the vice president, clinical research and development at Applied Genetic Technologies Corporation. Prior to that Dr. Ozden held leadership roles at GlaxoSmithKline, Quark Pharmaceuticals, Bausch & Lomb Pharmaceuticals and Carl Zeiss Meditec AG. Dr. Ozden received her M.D. from Hacettepe University School of Medicine. She completed her ophthalmology residency at Ankara University School of Medicine, and her clinical fellowship in Glaucoma at the New York Eye and Ear Infirmary.

Setareh Seyedkazemi, PharmD. Dr. Seyedkazemi has served as our chief development officer since January 2022. Prior to that, Dr. Seyedkazemi served as vice president, portfolio management for research and development at Pliant Therapeutics, a biopharmaceutical company, from October 2020 to December 2021. From May 2018 to October 2020, Dr. Seyedkazemi served as associate vice president clinical development and from November 2016 to April 2018 as executive director clinical development at Allergan (acquired by AbbVie in May 2020), a pharmaceutical company. Earlier in her career, Dr. Seyedkazemi served in roles of increasing responsibility at Tobira Therapeutics (acquired by Allergan in November 2016), Gilead Sciences, Johnson & Johnson and Abbott Laboratories, preceded by seven years in HIV clinical care and research. Dr. Seyedkazemi received a B.S. in Biology from Florida Atlantic University and a Doctor of Pharmacy from Nova Southeastern University, where she also completed a HIV/Infectious Disease residency.

Kishor Peter Soparkar Mr. Soparkar has served as our chief operating officer since June 2021 and previously was our chief legal officer from October 2019 to December 2022. Mr. Soparkar was previously chief legal officer, corporate secretary, head of human resources and head of compliance at Counsyl, Inc., a health technology company, from July 2016 to September 2018, where he led support for the company’s legal and human resources needs, debt and equity financings, investor interactions, IPO preparations and acquisition by Myriad Genetics, Inc. From November 2006 to July 2016, Mr. Soparkar served in several roles, most recently as Vice President, Associate General Counsel, at Jazz Pharmaceuticals plc, a global biopharmaceutical company. Prior to Jazz Pharmaceuticals, Mr. Soparkar worked at Latham & Watkins in London and San Francisco. He received a J.D. from New York University School of Law and a B.A. in economics and politics from Oberlin College.

EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

Our Executives

This Compensation Discussion and Analysis provides information regarding Adverum’s compensation philosophy, policies and practices, and includes information about the 2024 compensation paid or earned by those individuals who served as our named executive officers (“NEOs”) during the year ended December 31, 2024. These individuals were as follows:

Our Company

Adverum Biotechnologies is a clinical-stage company that aims to establish gene therapy as a new standard of care for highly prevalent ocular diseases. We discover and develop gene therapy product candidates intended to provide durable efficacy by inducing sustained expression of a therapeutic protein. Our lead product candidate, ixoberogene soroparvovec (“Ixo-vec”), is a single, in-office intravitreal injection gene therapy product designed to deliver long-term durable therapeutic levels of aflibercept associated with a robust, sustained treatment response, reducing the treatment burden and fluctuations in macular fluid associated with bolus anti-vascular endothelial growth factor intravitreal injections. Ixo-vec is currently being developed for the treatment of patients with wet AMD, also known as neovascular AMD. In November 2024, we announced top-line 52-week results from the ongoing LUNA Phase 2 clinical trial (“LUNA”). In March 2025, we initiated ARTEMIS, the first of two Phase 3 clinical trials of Ixo-vec in wet AMD. We intend to initiate AQUARIUS, the second phase 3 trial of Ixo-vec in wet AMD, in the second half of 2025. We intend to conduct ARTEMIS at U.S. sites and AQUARIUS globally. We are also developing an early-stage pipeline of gene therapy programs targeting the treatment of other highly prevalent ocular diseases. By overcoming the challenges associated with current treatment paradigms for debilitating ocular diseases, Adverum aspires to transform the standard of care, preserve vision, and create a profound societal impact around the globe.

Executive Summary

2024 Business and Performance Highlights

Fiscal performance for the year ended December 31, 2024

Clinical Trials Roadmap

Stockholder Engagement and Our 2024 Say-on-Pay Vote Result

At our 2024 Annual Meeting, the advisory say-on-pay proposal received support of approximately 88% of votes cast compared to approximately 75% in 2023 and 69% in 2022.

While we were pleased that the proposal passed in 2024, we intend to continue to engage with shareholders on corporate stewardship topics. Following the 2024 say-on-pay vote, the Compensation Committee continued its practice of substantial stockholder outreach. We reached out to our top 20 stockholders collectively holding approximately 78% of our common stock and engaged with all stockholders who requested a meeting. The topics discussed with our stockholders included our corporate strategy, financing plans, board culture and diversity. Our Chair of the Board, Patrick Machado, our Chair of the Compensation Committee, James Scopa, and our Chair of the Nominating and Governance Committee, Dawn Svoronos, led these discussions. No specific concerns regarding our executive compensation program were raised during those meetings.

The perspectives we heard from our stockholders were conveyed to all members of the Board of Directors and were reviewed and considered by the relevant Board committees. The Compensation Committee and the Board will continue to consider stockholder feedback and the outcomes of future say-on-pay votes when evaluating our executive compensation programs and policies and making compensation decisions for our NEOs.

We conduct a say-on-pay vote on an annual basis, and as such the next such vote will be conducted at our 2025 Annual Meeting. We will also be conducting an advisory vote on the frequency with which we should conduct say-on-pay votes at the 2026 Annual Meeting of Stockholders, as we are required to conduct such a “say on frequency” vote every six years.

Compensation Philosophy and Objectives

We believe in the importance of aligning the financial interests of our executives with those of our stockholders. A significant portion of our NEOs’ compensation is designed to be variable and tied to the achievement of key financial and strategic performance objectives, the performance of our stock price, or both, which helps us to incentivize our executive officers to create long-term value for our stockholders.

In particular, the compensation programs have been designed to accomplish the following objectives:

Compensation Decision Making Process

Role of the Compensation Committee

The Compensation Committee oversees our executive compensation program and is responsible for reviewing and approving all compensation of our executive officers, including our NEOs, authorizing stock incentive compensation, approving other incentive arrangements, and authorizing related agreements. During the fourth quarter of the year, the Compensation Committee meets to begin planning executive compensation for the next year. Its activities include undertaking a preliminary assessment of the goals achievement for the current calendar year, compensation analysis and comparison with our compensation peer group, reviewing current market data with respect to cash and equity compensation of our executives and establishing the performance measures which will be used to determine the executive officers’ annual cash bonus opportunities during the following year. In the first quarter of the year, the Compensation Committee meets to review and approve the achievement level of our prior year goals, sets the executive officers’ base salaries, and target annual cash and equity incentive opportunities in alignment with our overall compensation philosophy.

Role of the Independent External Advisor

The Compensation Committee retained Aon’s Human Capital Solutions practice, a division of Aon plc to serve as its independent compensation consultant. In this role, Aon reports directly to the Compensation Committee and uses the competitive market data described below to provide the Compensation Committee with compensation ranges that are consistent with our compensation peer group. The Compensation Committee considers analysis and advice from Aon when making compensation decisions related to our Chief Executive Officer and other NEOs.

During 2024, Aon assisted the Compensation Committee as follows:

In compliance with the disclosure requirements of the SEC and Nasdaq regarding the independence of compensation consultants, the Compensation Committee assessed the independence of our independent compensation consultant and determined that the engagement of Aon does not raise any conflicts of interest. During 2024, Aon received approximately $150,291 in compensation for its independent compensation consulting services.

Competitive Market Pay Information

Our compensation programs are designed to be competitive with companies of comparable size and industry with whom we compete for executive talent. The Compensation Committee works with Aon each year to identify a peer group of U.S.-based, publicly traded companies that can provide information on competitive market compensation data, including related to salary, annual incentives and long-term incentives. The Compensation Committee uses the market compensation data as one of several reference points for determining the form and amount of compensation. To determine actual compensation amounts, the Compensation Committee uses its discretion and considers other factors, in addition to the peer group and competitive market data, such as the responsibilities, performance, contributions and experience of each NEO.

The peer group for Adverum was developed using specific selection criteria to identify companies that are comparable in size, have similar business economics, and may be a potential source or destination of our executive talent. Specific criteria included:

In November 2023, the Compensation Committee evaluated the company’s peer group selection criteria and companies for alignment with governance and market best practices for executive compensation in 2024. The peer group continued to target life sciences companies in earlier stages of clinical development within relevant therapeutic focuses (ophthalmology and gene therapy). The market capitalization range was widened to 0.3x to 4x current valuation to account for significant market volatility, translating to a range between $25M and $400M based on a market capitalization at the time of ~$95M. This approach placed Adverum’s market capitalization in the 33rd percentile. In addition to the sector, stage and market capitalization, the Compensation Committee also considered the secondary criteria of years public and a number of full-time employees and included companies with three or more years of history as a public company and with generally between 50 and 400 employees, placing Adverum’s headcount in the 53^rd percentile.

The below peer group was proposed by Aon and approved by the Compensation Committee in November 2023. It was re-evaluated by Aon in April 2024 and confirmed that the below group continued to be the appropriate comparator for compensation decisions in 2024 (the “2024 Peer Group”).

In September 2024, the Compensation Committee evaluated the company’s peer group selection criteria and companies for alignment with governance and market best practices for executive compensation. The peer group targets life sciences companies in later stages of clinical development with an eye to include more companies conducting Phase 3 clinical trials and within relevant therapeutic focuses (ophthalmology and gene therapy) where possible. The market capitalization range was narrowed to 0.3x to 3x current valuation to account for significant market volatility, translating to a range between $50M and $500M based on our market value at the time of ~$164M. This approach placed Adverum’s market capitalization in the 36th percentile. In addition to the sector, stage and market capitalization, the Compensation Committee also considered the same as in prior year secondary criteria of years public and a number of full-time employees and continued to include companies with three or more years of history as a public company and with generally between 50 and 400 employees placing Adverum’s headcount in the 47^th percentile. Based on Aon’s recommendation regarding the updated criteria, the Compensation Committee approved the following peer group for 2025 executive compensation decisions in September 2024. The peer group below was also used to supplement the 2024 Peer Group and inform annual cash incentive determinations for 2024.

Risk Assessment

The Compensation Committee monitors our executive and non-executive compensation programs to ensure that our compensation policies and practices are consistent with the long-term success of Adverum and do not create risks that are reasonably likely to have a material adverse effect on us. The risk oversight includes a review of pay mix, performance metrics and design of our short-and long-term incentive programs, focusing on the programs with variability of payout, the ability of a participant to directly affect payout and controls around participant action and payout. The Compensation Committee determined that none of the compensation programs encourage or create excessive risk-taking and are reasonably unlikely to have a material adverse effect on Adverum.

Elements of Adverum’s Executive Compensation Program

During 2024, the compensation program for the NEOs consisted of cash, including base salary and annual cash incentives, and equity awards. The chart below outlines each element of the executive compensation program, the objectives of each component, and key features that may be used in determining each component.

Executive officers are eligible to participate in benefit programs available to the broader employee population.

A description of each component of compensation for the NEOs in 2024 is below, including a discussion of the factors considered in determining the applicable amount payable or achievable under each component.

Determination of Named Executive Officer Compensation

Base Salary

Base salaries are set to attract and retain executive talent. The determination of any particular executive’s base salary considers individual performance and contribution, experience in the role, market rates of pay for comparable roles and internal equity. Each year, our Chief Executive Officer proposes base salary adjustments, if any, for all NEOs, excluding himself, based on performance, changes in responsibilities, market data and other relevant factors. His proposal is subject to review by the Compensation Committee, which may accept the recommendations or make modifications to the proposal as it deems appropriate. Adjustments to the Chief Executive Officer’s salary are initiated and approved by the Compensation Committee.

Salary increases are discretionary, and during 2024 the Chief Executive Officer recommended salary adjustments designed to align our pay program with the market pay levels for comparable executive roles. The actual base salary earned by the NEOs in 2024 is reported in the Salary column of the Summary Compensation Table.