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

If your shares are held in street name, you must contact your broker or nominee for instructions as to how to change your vote. Your personal attendance at the Annual Meeting does not revoke your proxy. Your last vote, whether prior to or at the Annual Meeting, is the vote that we will count.

How is a quorum reached?

A quorum of stockholders is necessary to hold a valid meeting. The presence, in person or by proxy, of holders ofA quorum will be present if stockholders holding at least a majority of the total number of outstanding shares entitled to vote is necessary to constitute a quorum for the transaction of businessare present at the Annual Meeting.Meeting or represented by proxy. Shares held of record by stockholders or brokers, bankers or other nominees who do not return a valid proxy or attend the Annual Meeting in person

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will not be considered present or represented at the Annual Meeting and will not be counted in determining the presence of a quorum. The inspectors of election appointed for the Annual Meeting will determine whether a quorum is present.

Abstentions and broker non-votes, if any, will be counted for purposes of determining whether a quorum is present for the transaction of business at the meeting. If there is no quorum, the chairperson of the Annual Meeting or the holders of a majority of shares present at the Annual Meeting in person or represented by proxy may adjourn the Annual Meeting to another date.

What are “broker non-votes”?

As discussed above, when a beneficial owner of shares held in “street name” does not give instructions to the broker or nominee holding the shares as to how to vote on matters deemed to be “non-routine,” the broker or nominee cannot vote the shares. These unvoted shares are counted as “broker non-votes.”

What vote is required to approve each item and how are votes counted?

Votes cast by proxy or in person atThe following table summarizes the Annual Meeting will be counted byminimum vote needed to approve each proposal and the persons appointed by Syndax to act as tabulators for the meeting. The tabulators will count all votes FOR, AGAINST and to WITHHOLD,effect of abstentions and broker non-votes, as applicable, for each matter to be voted on at the Annual Meeting. Abstentions and broker non-votes are not counted as votes cast and, therefore, do not have the effect of votes in opposition to such proposals.non-votes.

For the election

Advisory approval of the executive compensation of our named executive officers

“For” votes from the holders of a majority of the voting power of the shares present in person or represented by proxy and entitled to vote on the matter.

Against

No effect

Non-routine

Ratification of the two Class II director nominees, each director nominee must receive a greater number of votes FOR his election than votes to WITHHOLD from such election to be elected a director, as this is an uncontested election of directors. Only FOR and WITHHOLD votes will affect the outcome. Abstentions will have no effect on Proposal 1. You may not vote your shares cumulatively for the election of directors. Proposal 1 is considered a non-routine matter. Therefore, if your shares are held by your bank, broker or other nominee in street name and you do not vote your shares, your bank, broker or other nominee cannot vote your shares on Proposal 1. As a result, broker non-votes will have no effect on Proposal 1.

For the ratification of the selection of Deloitte & Touche LLP as our independent registered public accounting firm for our fiscal year ending December 31, 2018, the votes cast FOR must exceed the votes cast AGAINST. Only FOR and AGAINST votes will affect the outcome. Abstentions will have no effect on the voting of Proposal 2.Proposal 2(1)

represented by such proxies in accordance with their best judgment. If you hold shares through a broker, bank or other nominee as described above, they will not be able to vote your shares on any other business that comes before the Annual Meeting unless they receive instructions from you with respect to such matter.

What happens if the meeting is postponed or adjourned?

Your proxy may be voted at the postponed or adjourned meeting. You will still be able to change your proxy until it is voted.

How can I find out the results of the voting at the Annual Meeting?

Preliminary voting results will be announced at the Annual Meeting. Final voting results will be published in a Current Report on Form 8-K or (“Form 8-K”) that we expect to file with the SEC within four business days after the Annual Meeting. If final voting results are not available to us in time to file a Form 8-K within four business days after the Annual Meeting, we intend to file a Form 8-K to publish preliminary results and, within four business days after the final results are known to us, file an additional Form 8-K to publish the final results.

What does it mean if I receive more than one Notice of Internet Availability?

It means that your shares may be registered in one or more names or multiple accounts at the transfer agent or with brokers. Please follow the instructions on the notices to ensure that all your shares are voted.

When are stockholder proposals due for the 20192024 Annual Meeting of Stockholders?

If you wish to submit proposals for inclusion in our proxy statement for the 20192024 annual meeting of stockholders or the 2019(the “2024 Annual Meeting”) we must receive them on or before December 8, 2018, pursuant to the proxy soliciting regulations of the SEC.6, 2023. Nothing in this paragraph shall require us to include in our proxy statement and proxy card for the 20192024 Annual Meeting any stockholder proposal that does not meet the requirements of the SEC in effect at the time. Any such proposal will be subject to Rule 14a-8 of the Securities Exchange Act of 1934, as amended the “Exchange Act.(the “Exchange Act”).

If you wish to nominate a director or submit a proposal for presentation at the 20192024 Annual Meeting, without including such proposal in next year’s proxy statement, you must be a stockholder of record and provide timely notice in writing to our Secretary at c/o Syndax Pharmaceuticals, Inc. 35 Gatehouse Drive, Building D, Floor 3, Waltham, Massachusetts 02451. To be timely, we must receive the notice not less than 90 days nor more than 120 days prior to the first anniversary of the 2023 Annual Meeting, that is, between January 23, 2019 and February 22, 2019; Meeting; provided, however, that in the event that the date of the 20192024 Annual Meeting is more than 30 days before or more than 60 days after such anniversary date, we must receive your notice (a) no earlier than the close of business on the 120th day prior to the currently proposed 20192024 Annual Meeting and (b) no later than the close of business on the later of the 90th day prior to the 20192024 Annual Meeting or the 10th day following the day on which we first make a public announcement of the date of the 20192024 Annual Meeting. Your written notice must contain specific information required in Section 2.13 of our amended and restated bylaws or “Bylaws.(“Bylaws”). In addition, stockholders who intend to solicit proxies in support of director nominees other than our nominees must also comply with the additional requirements of Rule 14a-19(b). For additional information about our director nomination requirements, please see our Bylaws.

Who should I call if I have any additional questions?

If you are the stockholder of record for your shares, please call Luke J. Albrecht, General Counsel and Secretary of the Company, at (781) 419-1400. If your shares are held in street name, please contact the telephone number provided on your voting instruction form or contact your broker or nominee holder directly.

PROPOSAL 1: ELECTION OF DIRECTORS

General

Our Board currently consists of seveneight directors. Our amendedAmended and restated certificateRestated Certificate of incorporationIncorporation (“Certificate of Incorporation”) provides for a classified Board consisting of three classes of directors. Currently, Classes III and IIIII each consist of twothree directors and Class IIII consists of threetwo directors. Each class serves a staggered three-year term. 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 or if sooner, until the director’s death, resignation or removal. Vacancies on the Board may be filled only by persons elected by a majority of the remaining directors. A director elected by the Board to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until the director’s successor is duly elected and qualified. There are currently no vacancies on the Board.

There are two directors in Class III whose term of office expires in 2018.2023. Upon the recommendation of the Nominating and Corporate Governance Committee, our Board has nominated the two individuals listed in the table below for election as directors at the Annual Meeting. Both Mr. ChenThe biographies below under “Information About Our Board” include information, as of the date of this proxy statement, regarding the specific and Dr. Evnin wereparticular experience, qualifications, attributes or skills of each director nominee that led the Nominating and Corporate Governance Committee to believe that each nominee should continue to serve on the board of directors. Each of the nominees listed below is currently a director of the Company who was previously elected to our Board by ourthe stockholders. If you elect the nominees listed below, they will each hold office until the annual meeting of stockholders in 20212026 and until each of their successors has been duly elected and qualified, or, if sooner, until the director’s death, resignation or removal. BothAll nominees are currently serving on our Board and have consented to being named in this proxy statement and to serve if elected.

If any nominee is unable or does not qualify to serve, you or your proxy may vote for another nominee proposed by the Board. If, for any reason, these nominees prove unable or unwilling to stand for election or cease to qualify to serve as directors, the Board will nominate alternates or reduce the size of the Board to eliminate the vacancies. The Board has no reason to believe that any of the nominees would prove unable to serve if elected. There are no arrangements or understandings between us and any director, or nominee for directorship, pursuant to which such person was selected as a director or nominee.

_____

(1) Ages as of April 7, 2023.

Vote Required

Directors are elected by a plurality of the votes cast atof the Annual Meeting by the holders of shares present in personduring the meeting or represented by proxy and entitled to vote on the election of directors. TheAccordingly, the two nominees receiving the most “FOR” votes will be elected as directors. In tabulating the voting results for the election of directors, only FOR and WITHHOLD votes will be counted. Abstentions and broker non-votes will have no effect on the outcome of Proposal 1. You may not vote your shares cumulatively for the election of directors. Shares represented by executed proxies will be voted, if authority to do so is not withheld, for the election of the two nominees named above. If any nominee becomes unavailable for election because of an unexpected occurrence, your shares will be voted for the election of a substitute nominee proposed by our Board. Your proxy cannot be voted for a greater number of persons than the number of director nominees named in this proxy statement.

Our Recommendation

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR

EACH OF THESE DIRECTOR NOMINEES FOR CLASS III DIRECTOR

(PROPOSAL 1 ON YOUR NOTICE OF INTERNET AVAILABILITY)

Information About Our Board of Directors

Set forth below are the names, ages and length of service of the remaining members of our Board whose terms continue beyond the Annual Meeting.

_____

(1) Ages as of April 7, 2023.

The principal occupation, business experience and education of each nominee for election as director and each continuing and retiring director are set forth below. Unless otherwise indicated, principal occupations shown for each director have extended for five or more years.

Nominees for Election

Henry Chen –

Pierre Legault is a Class I director who has served as a member of our board of directors since January 2017. Mr. ChenLegault also serves on the board of Bicycle Therapeutics (Chairman), which is a publicly traded company, as well as the boards of several private companies. Previously, he served on the board of Poxel Pharmaceuticals, Urovant, Clementia Pharmaceuticals, Armo BioSciences, OSI Pharmaceuticals, Tobira Therapeutics, NPS Pharmaceuticals, Forest Laboratories, Cyclacel Pharmaceuticals, Eckerd Pharmacy, Regado Biosciences, NephroGenex and several others. Mr. Legault served as Chairman of NephroGenex from 2012 through 2013 and Chief Executive Officer from 2014 through 2016, as Chief Executive Officer of Prosidion from 2010 through 2012, and Executive Vice President, Chief Financial Officer, and Treasurer of OSI Pharmaceuticals from 2009 through 2010. His prior senior executive experience also includes serving as President of Eckerd Pharmacy and as Executive Vice President and Chief Administrative Officer of Rite Aid Corporation. Mr. Legault studied at McGill University, HEC Montreal and Harvard Business School. He holds MBA, BAA, CA and CPA diplomas. We believe that Mr. Legault’s executive experience and his membership, including service as the chairman, on the board of directors of a number of biopharmaceutical companies qualify him to serve as a member of our Board.

Michael A. Metzger is a Class I director who has served as our Chief Executive Officer since February 2022 and previously served as our President and Chief Operating Officer since May 2015 and as a member of our board of directors since July 2019. Prior to joining us, Mr. Metzger was President and COO from December 2013 to October 2014 and President and Chief Executive Officer and a member of the board of directors of Regado Biosciences, Inc., a former publicly traded biotechnology company that merged with Tobira Therapeutics, Inc., from October 2014 to May 2015, where he oversaw the company’s successful merger with Tobira Therapeutics, Inc. in 2015. Previously, Mr. Metzger served as Executive Vice President and Chief Operating Officer at Mersana Therapeutics, Inc., a privately held biopharmaceutical company developing novel immunoconjugate therapies for cancer, from March 2011 to November 2013, and in senior business development positions including leading mergers and acquisitions at Forest Laboratories, LLC, which was acquired by Allergan plc, a publicly traded company, from 2006 to February 2011. Prior to Forest, Mr. Metzger served as Vice President Corporate Development at Onconova Therapeutics, Inc. and was a Managing Director at MESA Partners, Inc., a venture capital firm. Mr. Metzger currently serves on the board of CTI Biopharma Corp., a publicly traded biopharmaceutical company, as well as the board of a not-for-profit company. Mr. Metzger received a B.A. from George Washington University and an M.B.A. in Finance from the New York University Stern School of Business. We believe that Mr. Metzger’s executive experience and his membership on the board of directors of several biotechnology companies qualify him to serve as a member of our Board.

Continuing Directors

Martin H. Huber, M.D. is a Class II director who has served as a member of our board of directors since June 2015. Mr. Chen isSeptember 2021. Dr. Huber currently serves as the Managing PartnerPresident, Head of Delos Capital Fund LP, a healthcare-focused venture capital fund. Prior to establishing Delos in 2014, Mr. Chen was a PartnerR&D and Co-Headpreviously served as President, Chief Medical Officer of Asia at Permira Advisers LLP, a European private equity firm.Xilio Therapeutics, Inc. Prior to joining PermiraXilio in 2008, Mr. Chen spent nine yearsApril 2020, Dr. Huber served as Senior Vice President, Chief Medical Officer at TESARO, Inc. from September 2015 until its January 2019 acquisition by GlaxoSmithKline plc, and once acquired, as Senior Vice President, Clinical, until April 2020. Prior to TESARO, Dr. Huber served as Vice President, Oncology Clinical Research

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at Merck Research Laboratories from 2012 to 2015. Prior to Merck, he served in Investment Bankingroles of increasing responsibility at Goldman Sachs & Co.,Schering-Plough, Hoffmann-La Roche and Rhone-Poulenc Rorer, where he led teams in the areas of oncology clinical development, drug safety and pharmacovigilance. He was a Managing Director and co-headedpreviously an Assistant Professor of Oncology at the General Industrials Group, Asia (excluding Japan)University of Texas M.D. Anderson Cancer Center. Dr. Huber currently serves on the Board of Directors of Mersana Therapeutics, Inc., which covered the consumer retail, healthcare, industrials and transportation sectors. Prior to that, Mr. Chen wasis a corporate finance lawyer with Davis Polk & Wardwell LLP in New York and Hong Kong. Mr. Chen received a B.A. and an M.A.publicly traded company. Dr. Huber earned his M.D. from Harvard University and a J.D. from Harvard Law School.Baylor College of Medicine. We believe that Mr. Chen’sDr. Huber’s extensive experience and leadership, including in serving as head of research and development and as a chief medical officer in the venture capitalbiopharmaceutical industry, and his experience in the investment banking and legal industries givequalify him the qualifications, skills and financial expertise to serve onas a member of our board of directors.Board.

Luke Evnin, Ph.D. – Dr. Evnin

Jennifer Jarrett is a Class II director who has served as a member of our board of directors since May 2012. Dr. EvninSeptember 2018. Since October 2020, Ms. Jarrett has served as Chief Operating Officer of Arcus Biosciences, a biotechnology company. From February 2019 through September 2020, she served as Vice President of Corporate Development and Capital Markets of Uber Technologies, a technology company, and from June 2018 to January 2019 served as Arcus Biosciences’ Chief Operating Officer and Chief Financial Officer and as its Chief Business Officer and Chief Financial Officer from March 2017 to June 2018. From April 2016 to September 2016, Ms. Jarrett was the Chief Financial Officer of Medivation, a commercial biopharmaceutical company, which was acquired by Pfizer. Before Medivation, Ms. Jarrett spent 20 years in investment banking, most recently at Citigroup where she ran the firm’s west coast life sciences investment banking practice, and prior to that at Credit Suisse and Donaldson, Lufkin & Jenrette. Ms. Jarrett currently serves on the board of directors of Arcus Biosciences and Zura Bio, each of which is a publicly traded company, and previously served on the board of each of Arena Pharmaceuticals and Audentes Therapeutics. Ms. Jarrett received a B.A. in Economics from Dartmouth College and her M.B.A. from the Stanford Graduate School of Business. We believe that Ms. Jarrett’s extensive experience and leadership, including in investment banking and in serving as a chief financial officer and chief business officer in the biopharmaceutical industry, qualify her to serve as a member of our Board.

William Meury is a Class II director who has served as a managing directormember of our board of directors since September 2018. Since January 2023, Mr. Meury has served as President and Chief Executive Officer of Karuna Therapeutics, a biopharmaceutical company. From May 2020 through December 2022, Mr. Meury served as a Partner at MPMHildred Capital Management, a healthcare-focused venture capitalprivate equity firm since he co-founded MPM’s asset management business in 1997.focusing on the healthcare industry. Prior to joining MPM, Dr. Evnin spent seven years at Accel Partners, a venture capital firm, including four years as general partner. Dr. Evnin currently serves on a number of private company boards, and hasHildred Capital Management, Mr. Meury served as directorthe Chief Commercial Officer of Allergan, plc, a global pharmaceutical company from May 2016 through its acquisition by AbbVie plc. Mr. Meury previously served as Allergan’s President, Branded Pharma from March 2015 to May 2016 and joined Allergan in July 2014 as Executive Vice President, Commercial, North American Brands. He has significant experience in launching and commercializing healthcare products. Prior to joining Allergan, Mr. Meury served as Executive Vice President, Sales and Marketing at Forest Laboratories, Inc. He joined Forest in 1993 and held multiple roles of increasing responsibility in marketing, new products, business development, and sales. Before joining Forest, Mr. Meury worked in public accounting for Reznick Fedder & Silverman and in financial reporting for MCI Communications. Mr. Meury is currently on the board of directors Karuna Therapeutics, which is a publicly traded company, as well as on the boards of several public companies, including Enteromedics Inc, Epix Medical, Inc., Intercell AG, Metabasis Therapeutics, Inc. (acquired by Ligand Pharmaceuticals, Inc.), Oscient Pharmaceuticals Corp., Pacira Pharmaceuticals, Inc., Restore Medical, Inc. (acquired by Medtronic, Inc.), Sonic Innovations, Inc. and Signal Pharmaceuticals, Inc. (acquired by Celgene Corporation). Dr. Evnin received an A.B.private organizations. Mr. Meury earned his B.S. in Molecular Biology from Princeton University and a Ph.D. in BiochemistryEconomics from the University of California, San Francisco.Maryland. We believe that Dr. Evnin’sMr. Meury’s significant executive and commercial experience and leadership, including in the venture capital industry andlaunching healthcare products, as well as his servicebackground in finance, qualify him to serve as a directormember of other publicly traded and privately held life science companies give him the qualifications, skill and financial expertise to serve on our board of directors.Board.

Continuing Directors

Keith A. Katkin – Mr. Katkin is a Class III director who has served as a member of our board of directors since March 2017. SinceFrom September 2017 through March 2020, Mr. Katkin has served as the Chief Executive Officer and a member of the board of directors of Urovant Sciences Ltd., a privately heldpublicly traded biopharmaceutical company focused on developing novel therapies for urologic conditions.company. From March 2007 through January 2016, he was President and Chief Executive Officer of Avanir Pharmaceuticals, Inc., a publicly traded biopharmaceutical company, where he led the execution of the company’s sale to Otsuka Pharmaceutical Co., Ltd. in 2015. Mr. Katkin joined Avanir in July 2005 as the Senior Vice President of Sales and Marketing and a member of Avanir’s executive management team. While at Avanir, Mr. Katkin was responsible for creating and executing the plan that led to the approval of Nuedexta and the company’s growth to commercial success. Prior to joining Avanir, Mr. Katkin served as the Vice President, Commercial Development for Peninsula Pharmaceuticals, Inc., a privately held biopharmaceutical company, playing a key role in the concurrent initial public offering and ultimate sale of the company to Johnson and Johnson. Additionally, Mr. Katkin’s

employment experience includes leadership roles at InterMune, Amgen and Abbott Laboratories. Mr. Katkin currently serves onas a numberdirector at Eledon Pharmaceuticals, Inc. (Chairman), and Emergent BioSolutions, Inc., each of privatewhich is a publicly traded company, boards, and serves as directoran adviser to the board of several public companies, including Novus Therapeutics, Inc. (Chairman) and Rigel Pharmaceuticals, Inc.directors at Urovant. Mr. Katkin has an M.B.A. from the Anderson School at UCLA and earned a B.S. in Business and Accounting from Indiana University. Mr. Katkin is also a licensed Certified Public Accountant. We believe that among other experience, qualifications, attributes and skills, Mr. Katkin’s executive experience and his membership on the board of directors of several biotechnology companies qualify him to serve as a member of our board of directors.Board.

Briggs W. Morrison, M.D. – Dr. Morrison is a Class III director who has served as our President, Head of Research and Development since February 2022 and previously served as our Chief Executive Officer since June 2015 and as a member of our board of directors since July 2015. Dr. Morrison currently serves as a managing director of MPM Capital, a healthcare-focused venture

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capital firm, since June 2015. Prior to joining us, he served as Executive Vice President, Global Medicines Development and Chief Medical Officer at AstraZeneca plc, a publicly traded company, from January 2012 to June 2015, leading the company’s global, late-stage development organization and serving as a member of the AstraZeneca senior executive team. He previously held a number of positions at Pfizer Inc., a publicly traded company, from 2007 to January 2012 that culminated in his appointment as Head, Medical Affairs, Safety and Regulatory Affairs for Pfizer’s human health business, and also served in roles of increasing responsibility at Merck Research Laboratories, a division of Merck & Co., Inc., from 1995 to 2007, ascending to the role of Vice President, Clinical Sciences, Oncology, responsible for clinical development of all novel anti-cancer drugs. Dr. Morrison was chairman of the board of TransCelerate BioPharma Inc., an industry-funded company charged with improving aspects of clinical trials, from 2014 to 2015, a member of the executive committee of the Clinical Trials Transformation Initiative (CTTI) sponsored by FDA, and is on the board of ACRES (Alliance for Clinical Research ExcellenceArvinas, Inc, Carisma Therapeutics, Repare Therapeutics and Safety), ImunoMetWerewolf Therapeutics, Inc. and Oncorus, Inc.each of which is a publicly traded company, as well as the boards of several private companies. Dr. Morrison received a B.S. in biologyBiology from Georgetown University and an M.D. from the University of Connecticut. We believe that Dr. Morrison’s experience as an executive officer of other successful companies in the pharmaceutical industry gives him the qualifications, skills and financial expertise to serve onas a member of our board of director.Board.

Dennis G. Podlesak – Mr. Podlesak is a Class III director who has served as chairman of our board of directors since December 2008. Since November 2007, Mr. Podlesak has served as a partner atis the Chief Executive Officer and Managing Partner of Canaan Partners’ Axceliux LLC, and is an Advisory Partner of Domain Associates, LLC awhich he joined in November 2007, both of which are life science-focused venture capital firm. While at Domain,firms. Mr. Podlesak previously served as the Chairman of the board of Tobira Therapeutics, a publicly traded biopharmaceutical company that was acquired by Allergan plc in November 2016.plc. Mr. Podlesak also served on the board of Avanir Pharmaceuticals, a publicly traded biopharmaceutical company, through its acquisition by Otsuka Pharmaceuticals, in January 2015 and was on thea founding board member of Rightcare Solutions, which was acquired by Cardinal Health’s Naviheath division in December 2015.Health. Mr. Podlesak was also the founder and the Chief Executive Officer of Calixa Therapeutics, Inc., a privately held biopharmaceutical company that was acquired by Cubist Pharmaceuticals, and Mr. Podlesak was the Executive Chairman of Corthera, Inc., a privately held biopharmaceutical company which was acquired by Novartis AG. Earlier in his career, Mr. Podlesak served as the Founder and Chief Executive Officer of Cerexa, Inc., a privately held biotechnology company, which became a wholly owned subsidiary of Forest Laboratories, Inc. after being acquired by Forest. Prior to Cerexa, Mr. Podlesak served as the Chief Executive Officer of Peninsula Pharmaceuticals Inc., a privately held pharmaceutical company, and led the sale of Peninsula to Johnson & Johnson'sJohnson’s Ortho-McNeil Pharmaceutical subsidiary. Prior to joining Peninsula, Mr. Podlesak held various executive management positions at Novartis AG, a publicly traded healthcare company, Allergan, plc, a publicly traded healthcare company and Smith Kline Beecham (now GlaxoSmithKline plc, a publicly traded pharmaceutical company). Mr. Podlesak is the Chairman of Adynxx and serves on other private company boards. Mr. Podlesak received a B.A. and an M.B.A. from Pepperdine University, and has completed postgraduate studies at the Wharton School, University of Pennsylvania. We believe that Mr. Podlesak’s experience in the venture capital industry, his experience as the Chief Executive Officer and Chairman of other successful companies in the biotechnology industry, his over 20 years of strategic, operational and commercial experience in the pharmaceutical industry, and his service as a director of other publicly traded and privately held life science companies give him the qualifications, skills and financial expertise to serve on our board of directors.

Fabrice Egros, Ph.D. – Dr. Egros is a Class I director who has served as a member of our board of directors since September 2013. Since October 2015, Dr. Egros has served as President, Asia Pacific and Japan of Lupin Limited, an Indian publicly traded pharmaceutical company. From November 2012 to September 2015, Dr. Egros served as the Deputy Chief Executive Officer/Chief Operating Officer of NovaMedica LLC, a privately held pharmaceutical company, and was its Chief Operating Officer and a member of its board of directors from July 2012 to September 2015. From February 2011 to July 2012, Dr. Egros served as the Chief Operating Officer of Xanodyne

Pharmaceuticals, Inc., a privately held pharmaceutical company. From September 2009 to February 2011, he served as the Senior Vice President, Corporate Business Development and Strategy of UCB, S.A., a publicly traded biopharmaceutical company. From August 2006 to August 2009, Dr. Egros served as the President of UCB, Inc., a subsidiary of UCB, S.A., and from September 2003 to August 2006, he served as the President of UCB Japan Co. Ltd., a subsidiary of UCB, S.A. Prior to joining UCB, Dr. Egros held various management and executive positions at Parke-Davis, Warner Lambert Company, a privately held pharmaceutical company, and Sanofi, formerly known as Sanofi-Aventis, a publicly traded pharmaceutical company. Dr. Egros received a B.S. in Pharmacokinetics and Metabolism and a Pharm.D. and Ph.D. in Pharmaceutical Sciences from Chatenay Malabry University, and has participated in the Advanced Management Program at Harvard University. He also holds an MBA from Schiller International University. We believe that, among other experience, qualifications, attributes and skills, Dr. Egros’ experience as an executive officer of other successful companies in the pharmaceutical industry gives him the qualifications, skills and financial expertise to serve on our board of directors.Board.

Pierre Legault – Mr. Legault is a Class I director who has served as a member of our board of directors since January 2017. Mr. Legault also serves on the board of Poxel Pharmaceuticals (Chairman), Armo BioSciences, Artios Pharma (Chairman) and Clementia Pharmaceuticals. Previously, he served on the board of Tobira Therapeutics, NPS Pharmaceuticals, Forest Laboratories, Cyclacel Pharmaceuticals, Eckerd Pharmacy, Regado Biosciences, NephroGenex and several others. Mr. Legault served as Chairman of NephroGenex from 2012 through 2013 and Chief Executive Officer from 2014 through 2016, as Chief Executive Officer of Prosidion from 2010 through 2012, and Executive Vice President, Chief Financial Officer, and Treasurer of OSI Pharmaceuticals from 2009 through 2010. His prior senior executive experience also includes serving as President of Eckerd Pharmacy and as Executive Vice President and Chief Administrative Officer of Rite Aid Corporation. He also held several senior positions with Sanofi-Aventis and predecessor companies, including President of Worldwide Dermatology Operations. Mr. Legault studied at McGill University, HEC Montreal and Harvard Business School. He holds an MBA, BAA, CA, CPA and Six Sigma Green Belt diplomas. We believe that, among other experience, qualifications, attributes and skills, Mr. Legault’s executive experience and his membership on the board of directors of a number of biopharmaceutical companies qualify him to serve as a member of our board of directors.

EXECUTIVE OFFICERS

The following table sets forth information regarding our executive officers who are not directors, as of the date of this proxy statement:

Michael A. Metzger – Mr. Metzger

Luke J. Albrecht has served as our General Counsel since August 2016 and as our Secretary since September 2016. Previously he was Vice President, General Counsel and Secretary, Chief OperatingCompliance Officer for Boston Heart Diagnostics Corporation from March 2013 to May 2016. Prior to Boston Heart, Mr. Albrecht was in-house counsel for Advanced BioHealing, Inc. where he held senior legal positions from August 2009 and, following the company’s acquisition by Shire plc, with Shire Regenerative Medicine, to December 2012. He practiced corporate and transactional law at the international law firms McDermott Will & Emery LLP from August 2004 to July 2007 and Cooley LLP from July 2007 to August 2009. Mr. Albrecht received a B.A. from the University of New Hampshire and a J.D. from Suffolk University Law School.

Anjali Ganguli, Ph.D. has served as our Chief Business Officer since September 2021 and previously was Vice President, Corporate Development leading business development and investor relations since joining the company in May 2015. Prior to joining us, Mr. MetzgerSyndax, Dr. Ganguli was President and COO from December 2013 to October 2014 and President and Chief Executive Officer and a member of the board of directors ofVP Corporate Development at Regado Biosciences Inc., a former publicly traded company that merged with Tobira Therapeutics, Inc., from OctoberFebruary 2014 to May 2015, where he oversawshe aided in the company’s successful merger with Tobira Therapeutics, Inc. in 2015. Previously, Mr. Metzger served as Executive Vice PresidentDr. Ganguli held roles within Marketing and Chief Operating Officer at Mersana Therapeutics, Inc., a privately held biopharmaceutical company developing novel immunoconjugate therapies for cancer, from March 2011 to November 2013, and in senior business development positions including leading mergers and acquisitionsCommercial Assessments at Forest Laboratories, LLC, which was acquired by Allergan plc,prioritizing due diligence opportunities and supporting business development transactions of clinical stage assets; and served as an equity research analyst at CIBC World Markets, covering mid and small cap biopharmaceutical companies. Dr. Ganguli received a B.S. in Biological Chemistry at the University of Chicago, a Ph.D. in Medicinal Chemistry at the University of Michigan and conducted research as a NIH post-doctoral fellow at the University of California, Berkeley.

Keith A. Goldan has served as our Chief Financial Officer since June 2022. Prior to joining Syndax, Mr. Goldan served as Chief Financial Officer of Optinose, a publicly traded specialty pharmaceutical company, from 2006since January 2017, where he helped build the infrastructure to February 2011.support the launch of its lead product in the United States. Prior to Forest,Optinose, he served as Chief Financial Officer and Senior Vice President of Fibrocell, a publicly traded cell and gene therapy company. Mr. MetzgerGoldan’s experience also includes Chief Financial Officer roles at NuPathe, PuriCore plc and Biosyn as well as financial roles at ViroPharma and KPMG. In these positions, Mr. Goldan led finance, accounting, IT, HR and corporate development teams and successfully raised capital through multiple IPOs, capital markets transactions and financing vehicles. Mr. Goldan received a B.S. in Finance from the Robert H. Smith School of Business at the University of Maryland and an M.B.A. from the Wharton School at the University of Pennsylvania.

Catherine Madigan, M.D. has served as our Chief Medical Officer since March 2022. Prior to joining the Company, Dr. Madigan served as Vice President, Head of Clinical Development at Syros Pharmaceuticals. Prior to joining Syros, she served as Senior Medical Director at Alnylam Pharmaceuticals, and was a Medical Director in Biogen’s Rare Disease Innovation Unit. Dr. Madigan previously held various academic positions of increasing responsibility at University of California San Diego/ Rady Children’s Hospital San Diego. Dr. Madigan received a B.A. in Asian Studies from Dartmouth College and an M.D. from the Keck School of Medicine of the University of Southern California.

Alexander Nolte has served as the Company’s Vice President, Chief Accounting Officer since September 2021 and previously served as Vice President, Corporate Development at Onconova Therapeutics, Inc., from 2001 until 2006,Finance since February 2021 and was a Managing Director at MESA Partners, Inc., a venture capital firm, from 1997as Corporate Controller since April 2017. Prior to 2001. Mr. Metzger currently serves on the board of CTI Biopharma Corp., a publicly traded biopharmaceutical company and Tarveda Therapeutics. Mr. Metzger received a B.A. from George Washington University and an M.B.A. in Finance from the New York University Stern School of Business.

Michael L. Meyers, M.D., Ph.D. – Dr. Meyers hasthat, he served as our Senior Vice President, Chief Medical Officer since May 2016. Dr. Meyers previously served as our Senior Vice President, Chief Development OfficerCorporate Controller from AugustJuly 2015 to April 2016. Prior2017 at CoLucid Pharmaceuticals, responsible for the financial operations of the company. From September 2013 to joining us, Dr. Meyers held a number of senior roles at Johnson & Johnson, a publicly traded company, serving as Vice President, GU Oncology, Compound and Clinical Leader, and as Vice President, Oncology Scientific Innovation in Johnson and Johnson’s London Innovation Centre. Dr. Meyers also led the U.S. Oncology Medical Affairs team at Aventis Pharmaceuticals Inc., a privately held life sciences company, predecessor to Sanofi-Aventis U.S. LLC, and worked in oncology clinical development at the Schering-Plough Research Institute. Dr. Meyers served on the Memorial Sloan Kettering Cancer Center faculty, specializing in Clinical Immunology and melanoma. He received his M.D. and his Ph.D. in Microbiology and Immunology from Albert Einstein College of Medicine in New York and was elected to the American Osteopathic Association. Dr. Meyers completed his residency in Internal Medicine at Columbia Presbyterian Medical Center and his fellowship, whereJuly 2015, he served as Chief FellowDirector of Revenue Recognition and International Accounting at Aegerion Pharmaceuticals. From March 2008 to September 2013, Mr. Nolte held several finance positions at Genzyme Corporation. He began his professional career at KPMG Accountants NV in Medical Oncology, at Memorial Sloan Kettering Cancer Center.the Netherlands and PricewaterhouseCoopers LLP in Boston, Massachusetts. Mr. Nolte received his B.S. in Accountancy, from The Hague University (the Netherlands) and is a licensed Certified Public Accountant in the State of Massachusetts.

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Peter Ordentlich, Ph.D. – Dr. Ordentlich co-founded the Company in October 2005 and has served as our Chief Scientific Officer since September 2016. Dr. Ordentlich previously served as our Chief Technical Officer from November 2013 to August 2016, our Vice President, Translational Medicine from January 2012 to October 2013, our Executive Director, Translational Science from January 2011 to December 2011, and our Director, Scientific Affairs and Strategic Alliances from January 2008 to December 2010. Prior to founding the company, Dr. Ordentlich was a scientist at the Salk Institute for Biological Studies, a biological research non-profit organization. He also spent five years as a research scientist at X-Ceptor Therapeutics, Inc., a drug discovery company, which was acquired by Exelixis, Inc. Dr. Ordentlich received a B.A. in Biochemistry and a Ph.D. in Immunology from the University of Pennsylvania.

Richard P. Shea – Mr. SheaSteve M. Sabus has served as our Chief FinancialCommercial Officer since February 2017.December 2022. Prior to joining Syndax, Mr. Shea previouslySabus served as a member of our board of directors from January 2014 to February 2017. From July 2007 through December 2016,Chief Commercial Officer at Turning Point Therapeutics before its acquisition by BMS. Before Turning Point, Mr. Shea servedSabus held senior commercial roles at Astellas Pharma for over 15 years, most recently serving as Senior Vice President, Head of Oncology. Earlier in his tenure at Astellas, Mr. Sabus headed the U.S. Medical Specialties business unit where he designed commercial strategies to extend the portfolio and Chief Financial Officerincrease market impact across therapeutic areas. Additionally, he was the General Manager of Momenta Pharmaceuticals Inc., a publicly traded biotechnology company, and was its Vice President and Chief Financial Officer since October 2003. Prior to joining Momenta,Astellas Canada, where his team launched Xospata®. Before Astellas, Mr. Shea served as Chief Operating Officer and Chief Financial OfficerSabus spent 16 years at Johnson & Johnson in commercial roles of Variagenics Inc., a publicly traded pharmacogenomics company, that was merged with Hyseq Pharmaceuticals Inc., and as Vice President, Financeincreasing responsibility. Mr. Sabus received his Bachelor of Genetics Institute, Inc., a publicly traded biotechnology company, which was acquired by Wyeth Pharmaceuticals, Inc., which was then acquired by Pfizer, Inc. Mr. Shea currently serves onArts in Marketing & Sales Management at the boardUniversity of Synlogic, Inc., a publicly traded biopharmaceutical company. Mr. Shea received an A.B. from Princeton University and an M.B.A. from the Public Management Program at Boston University.Northern Iowa.

THE BOARD OF DIRECTORS AND ITS COMMITTEES

Board CompositionDiversity

We currently have seven directors and

The Board diversity matrix, below, provides the termsdiversity statistics for our Board of office ofDirectors. Our previous year’s disclosure can be found in our definitive proxy statement filed with the directors are divided into three classes:SEC on March 29, 2022.

Class I consists of Dr. Egros and Mr. Legault, Class II consists of Mr. Chen and Dr. Evnin, and Class III consists of Dr. Morrison and Messrs. Katkin and Podlesak. At each Annual Meeting, the successors to directors whose terms will then expire shall serve from the time of election and qualification until the third Annual Meeting following election and until their successors are duly elected and qualified or if sooner, until the director’s death, resignation or removal. Any additional directorships resulting from an increase in the number of directors will be distributed among the three classes so that, as nearly as possible, each class will consist of one-third of the directors. This classification of the Board may have the effect of delaying or preventing changes in control or management of our company.

Board Independence

Rule 5605 of the Nasdaq Listing Rules requires that independent directors compose a majority of a listed company’s board of directors. In addition, the Nasdaq Listing Rules require that, subject to specified exceptions including certain phase-in rules, each member of a listed company’s audit, compensation, and nominating and corporate governance committees be independent and that audit committee members also satisfy independence criteria set forth in Rule 10A-3 under the Exchange Act. Under Nasdaq Listing Rule 5605(a)(2), a director will only qualify as an “independent director” if, in the opinion of our Board, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. To be considered independent for purposes of Rule 10A-3 under the Exchange Act, a member of an audit committee of a listed company may not, other than in his or her capacity as a member of the audit committee, the board of directors, or any other board committee: (i) accept, directly or indirectly, any consulting, advisory, or other compensatory fee from the company or any of its subsidiaries; or (ii) be an affiliated person of the 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 Rule 10C-1 under the Exchange Act and Nasdaq Listing Rule 5605(d)(2). Pursuant to Rule 10C-1 under the Exchange Act and Nasdaq Listing Rule 5605(d)(2), in affirmatively determining the independence of a member of a compensation committee of a listed company, the board of directors must consider all factors specifically relevant to determining whether that member has a relationship with the company that is material to that member’s ability to be independent from management in connection with the duties of a compensation committee member, including: (a) the source of compensation of such member, including any consulting, advisory or other compensatory fee paid by the company to such member; and (b) whether such member is affiliated with the company, a subsidiary of the company or an affiliate of a subsidiary of the company.

Consistent with these considerations, after review of all relevant identified transactions or relationships between each director, or any of his or her family members, and the Company, its senior management and its independent auditors, our Board has affirmatively determined that all our directors, except Michael A. Metzger, who serves as our Chief Executive Officer, and Briggs W. Morrison, M.D., who serves as our Chief Executive Officer,President and Head of Research and Development, are independent directors within the meaning of the applicable Nasdaq Listing Rules and SEC rules. Our Board also determined that Richard P. Shea was an independent director within the meaning of the applicable Nasdaq Listing Rules and SEC rules during the period in which he served as the Company’s director, which was before he was appointed as our Chief Financial Officer. In making this determination, our Board has determined, upon the recommendation of our Nominating and Corporate Governance Committee, that none of these directors has a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director

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and is independent within the meaning of the director independence standards established by the SEC and the Nasdaq Listing Rules. The Board also determined that each member of our Audit, Compensation and Nominating and Corporate Governance Committees satisfies the independence standards for such committees established by the SEC and the Nasdaq Listing Rules, as applicable.

At least annually, our Board will evaluate all relationships between us and each director considering relevant facts and circumstances for the purposes of determining whether a material relationship exists that might signal a

potential conflict of interest or otherwise interfere with such director’s ability to satisfy his or her responsibilities as an independent director. Based on this evaluation, our Board will make an annual determination of whether each director is independent within the meaning of Nasdaq and the SEC independence standards.

Board Meetings and Attendance

Our Board held sevenfour meetings during the fiscal year ended December 31, 2017.2022. Each of the incumbent directors attended at least 75%100% of the total of the in-person meetings of the Board and at least 75% of the meetings of the committees of the Board on which he or she served during the fiscal year ended December 31, 20162022 (in each case, which were held during the period for which he or she was a director and/or a member of the applicable committee). It is our policy to encourage our directors to attend the Annual Meeting. We anticipate that a majorityAll of the membersour directors attended our 2022 annual meeting of the Board will attend the Annual Meeting.stockholders.

Board Committees

Our Board has established threefour standing committees: the Audit Committee, the Compensation Committee, and the Nominating and Corporate Governance Committee and the Science and Technology Committee, each of which is composed solely of independent directors and is described more fully below. Each of the Audit Committee, Compensation Committee and Nominating and Corporate Governance Committeecommittee operates pursuant to a written charter and each committee reviews and assesses the adequacy of its charter and submits its charter to the Board for approval. The charters for the Audit Committee, Compensation Committee and Nominating and Corporate Governance Committeeeach committee are all available on the investor relations portion of our website, www.syndax.com.www.syndax.com. The inclusion of our website address here and elsewhere in this proxy statement does not include or incorporate by reference the information on our website into this proxy statement.

The following table provides membership and meeting information for the year ended December 31, 20172022 for each committee:

Chair Member

Financial Expert

Below is a description of each committee of the Board.

Audit Committee

Messrs. Katkin, Legault and Shea, as well as Drs. Egros and Sledge,Podlesak, served as members of the Audit Committee during 2017,2022, with Mr. Shea initiallyLegault serving as chair of the committee. Effective February 13, 2017, Mr. Shea resigned from the Audit Committee in connection with his appointment as Chief Financial Officer of the Company

and Mr. Legault was appointed as chair of the Audit Committee. Mr. Katkin was appointed to the Audit Committee on March 29, 2017. Dr. Sledge resigned from the Audit Committee upon his retirement from the Board on May 17, 2017. Our Board has determined that each current member of the Audit Committee meets the independence requirements of Rule 10A-3 under the Exchange Act and the applicable listing standards of Nasdaq and that Mr. Shea and Dr. Sledge met the independence requirements of Rule 10A-3 under the Exchange Act and the applicable listing standards of Nasdaq during the time that they each served on the Audit Committee.Nasdaq. Our Board determined that Mr. Shea was an “audit committee financial expert” during his service on the Audit Committee and that Messrs. Katkin and Legault are currently each an “audit committee financial expert,” both within the meaning of the SEC regulations and applicable listing standards of Nasdaq. During the fiscal year ended December 31, 2017, the Audit Committee met eight times. The report of the Audit Committee is included in this proxy statement under “Report of the Audit Committee.” The functions of our Audit Committee include, among other things:

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Compensation Committee

Drs. Evnin and Sledge, and Messrs. Katkin, Legault and Podlesak served as members of the Compensation Committee during 2017,2022, with Dr. EvninMr. Katkin serving as chair of the committee. On January 31, 2017, Dr. Sledge resigned from the Compensation Committee and Mr. Legault was appointed to the Compensation Committee. Our Board has determined that each current member of the Compensation Committee is “independent”

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“independent” as defined under the applicable listing standards of Nasdaq. During the fiscal year ended December 31, 2017, the Compensation Committee met seven times. The functions of our Compensation Committee include, among other things:

Committee may review and consider, as appropriate, materials such as financial reports and projections, operational data, tax and accounting information, tally sheets that set forth the total compensation that may become payable to executives in various hypothetical scenarios, executive and director stock ownership information, company stock performance data, analyses of historical executive compensation levels and current Company-wide compensation levels, including analyses of executive and director compensation paid at a peer group of other companies approved by our Compensation Committee.

The specific determinations of the Compensation Committee with respect to executive compensation for fiscal 2022 are described in greater detail in the Compensation Discussion and Analysis section of this proxy statement.

Nominating and Corporate Governance Committee

Drs. Evnin, Kamdar and RoystonMs. Jarrett and Messrs. Katkin, Legault and Podlesak served as members of the Nominating and Corporate Governance Committee during 2017,2022, with Dr. Kamdar initially serving as chair of the committee. On March 29, 2017, Mr. Katkin was appointed to the Nominating and Corporate Governance Committee and on November 9, 2017, Mr. Legault was appointed to the committee. On May 17, 2017, Drs. Kamdar and Royston resigned from the Nominating and Corporate Governance Committee upon their retirement from the Board and Mr. Podlesak was appointedserving as chair of the committee. Our Board has determined that each member of the Nominating and Corporate Governance Committee is “independent” as defined under the applicable listing standards of Nasdaq. During fiscal year ended December 31, 2017, the Nominating and Corporate Governance Committee met five times. The functions of our Nominating and Corporate Governance Committee include, among other things:

be made by any stockholder of record entitled to vote for the election of directors at such meeting who provides timely notice in writing to our Secretary at our principal executive offices. To be timely, we must receive the notice not less than 90 days nor more than 120 days prior to the first anniversary of the date of the prior year’s annual meeting; provided, however, that in the event that the date of the annual meeting is more than 30 days before or more than 60 days after such anniversary date, we must receive the stockholder’s notice (i) no earlier than the close of business on the 120th day prior to the proposed date of the annual meeting and (ii) no later than the close of business on the later of the 90th day prior to the annual meeting or the 10th day following the day on which we first make a public announcement of the date of the annual meeting. The stockholder’s written notice must contain specific information required in Section 2.13 of our Bylaws. For additional information about our director nomination requirements, please see our Bylaws.

Minimum Qualifications

Our Nominating and Corporate Governance Committee will consider,considers, among other things, the following qualifications, skills and attributes when recommending candidates for the Board’s selection as director nominees for the Board and as candidates for appointment to the Board’s committees: a director nominee shall have the highest personal and professional integrity, shall have demonstrated exceptional ability and judgment, and shall be most effective, in conjunction with the other director nominees to the Board, in collectively serving the long-term interests of the stockholders.

In evaluating proposed director candidates, our Nominating and Corporate Governance Committee may consider, in addition to the minimum qualifications and other criteria for board membership approved by the Board from time to time, all facts and circumstances that it deems appropriate or advisable, including, among other things, diversity considerations, the skills of the proposed director candidate, his or her depth and breadth of professional experience or other background characteristics, his or her independence and the needs of the Board. We have no formal policy regarding board diversity.diversity, but believe that our Board, taken as a whole, should embody a diverse set of skills, experiences and backgrounds. In this regard, the committee also takes into consideration the diversity (for example, with respect to gender, race and national origin) of our board members. The committee does not make any particular weighting of diversity or any other characteristic in evaluating nominees and directors. Our Nominating and Corporate Governance Committee’scommittee’s priority in selecting board members is identification of persons who will further the interests of our company through his or her established record of professional accomplishment, the ability to contribute positively to the collaborative culture among board members, and professional and personal experiences and expertise relevant to our growth strategy.

Non-Management Director Meetings

In addition to the meetings of the committees of the Board described above, in connection with the Board meetings, the independent directors met four times in regularly scheduled executive sessionsessions during the fiscal year ended December 31, 2017.2022. The Chairman of the Board presides at these executive sessions. The Audit Committee and the Board have established a procedure whereby interested parties may make their concerns known to independent directors, which is described on our website.

Compensation Committee Interlocks and Insider Participation

The Compensation Committee consists of the following members: Pierre Legault, Keith A. Katkin and Dennis G. Podlesak. No voting member of the Compensation Committee is an officer of the Company or has served as an officer of the Company, including its affiliates, at any time. None of our executive officers serve as a member of the Compensation Committee of any other company that has an executive officer serving as a member of the Company’s Board of Directors. None of our executive officers serve as a member of the board of directors of any other company that has an executive officer serving as a member of our Board’s Compensation Committee. None of our executive officers serve as a member of the

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Leadership Structure and Risk Oversight

ThisThe positions of our Chairman of the Board and Chief Executive Officer of the Company are separated, with Mr. Podlesak serving as Chairman and Dr. MorrisonMr. Metzger as our Chief Executive Officer. As a general policy, our Board believes that separation of the positions of Chairman and Chief Executive Officer reinforces the independence of the Board from management, creates an environment that encourages objective oversight of management’s performance and enhances the effectiveness of the Board.

Our Board recognizes that depending on the circumstances, other leadership models, such as combining the role of Chairman of the Board with the role of Chief Executive Officer, might be appropriate. Accordingly, our Board may periodically review its leadership structure. Our Board believes its administration of its risk oversight function has not affected its leadership structure.

Our Board oversees the management of risks inherent in the operation of our business and the implementation of our business strategies. Our Board performs this oversight role by using several different levels of review. In connection with its reviews of the operations and corporate functions of our company, our Board addresses the primary risks associated with those operations and corporate functions. In addition, our Board reviews the risks associated with our Company’s business strategies periodically throughout the year as part of its consideration of undertaking any such business strategies. Additionally, the Board reviews at least annually the Company’s business initiatives, capital projects and budget matters.

Certain of the committees of our Board also overseesoversee the management of ourthe Company’s risk that falls within thesuch committee’s areas of responsibility. In performing this function, each committee has full access to management,

as well as the ability to engage advisors. Our Chief Financial Officer and/or our Chief Accounting Officer periodically provides reports to the Audit Committee and is responsible for identifying, evaluating and implementing risk management controls and methodologies to address any identified risks. In connection with its risk management role, our Audit Committee meets privately with representatives from our independent registered public accounting firm. The Audit Committee, as part of its responsibilities, oversees the Company’s significant financial and operational risk exposures, including but not limited to accounting matters, liquidity and credit risks, corporate tax positions, insurance coverage, and cash investment strategy and results. The Audit Committee is also responsible for overseeing the management of risks relating to the performance of the Company’s internal audit function (if required) and its independent registered accounting firm, as well as the Company’s systems of internal controls and disclosure controls and procedures. Audit committee responsibilities also include oversight of cybersecurity risk management, and, to that end, the committee typically meets at least annually with both IT and business personnel responsible for cybersecurity risk management and receives periodic reports from the head of cybersecurity risk management, as well as incidental reports as matters arise. The Compensation Committee is responsible for overseeing the Company’s major compensation-related risk exposures, including risks related to executive compensation and overall compensation and benefit strategies, plans, arrangements, practices and policies. The Nominating and Corporate Governance Committee oversees the Company’s major legal compliance risk exposures, including the company’s procedures and any related policies with respect to risk assessment and risk management. The Science and Technology Committee assists and advises the Board with respect to scientific research and development matters. These committees provide regular reports to the full Board.

Compensation Committee Interlocks and Insider Participation

During 2017, our Compensation Committee consisted of Drs. Evnin and Sledge, and Messrs. Legault and Podlesak. None of the members of our Compensation Committee has at any time during the last fiscal year been one of our officers or employees. None of our executive officers currently serves, or in the last fiscal year has served, as a member of the board of directors or compensation committee of any entity that has one or more executive officers serving on our Board or Compensation Committee. Further, no member of our Compensation Committee had any relationship requiring disclosure by us under Item 404 of Regulation S-K.

Code of Business Conduct and Ethics

We have adopted a Code of Business Conduct and Ethics that applies to all officers, directors and employees. The Code of Business Conduct and Ethics is available on our website at www.syndax.com. If we make any substantive amendments to the Code of Business Conduct and Ethics or grants any waiver from a provision of the Code to any executive officer or director, we will promptly disclose the nature of the amendment or waiver on its website.

Corporate Governance Guidelines

The Board has adopted Corporate Governance Guidelines to assure that the Board will have the necessary authority and practices in place to review and evaluate our business operations as needed and to make decisions that are independent of our management. The guidelines are also intended to align the interests of directors and management with those of our stockholders. The Corporate Governance Guidelines set forth the practices the Board intends to follow with respect to, among other things, board membership criteria and selection, board meetings and committees, risk oversight, management review and responsibility, including performance evaluation and succession planning. The Corporate Governance Guidelines are available in the “Investors–Corporate Governance” section of our website, www.syndax.com.

Environmental, Social and Governance Commitment

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Stockholder Communications with Our Board of Directors

The Board has adopted a formal process by which stockholders may communicate with the Board or any of its directors. Stockholders wishing to communicate directly with our Board may send correspondence to our Secretary, c/o Syndax Pharmaceuticals, Inc., 35 Gatehouse Drive, Building D, Floor 3, Waltham, Massachusetts 02451. Our Secretary will forward all comments directly to the Board. These communications will be reviewed by the Secretary of the Company designated by the Board who will determine whether the communication is appropriate for presentation to the Board or the relevant director. The purpose of this screening is to allow the Board to avoid having to consider irrelevant or inappropriate communications (such as advertisements, solicitations and hostile communications).

THE EXECUTIVE COMPENSATION PAID TO OUR NAMED EXECUTIVE OFFICERS

(PROPOSAL 2:2 ON YOUR NOTICE OF INTERNET AVAILABILITY)

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PROPOSAL 3: RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The firm of Deloitte & Touche LLP, independent registered public accounting firm, has been selected by the Audit Committee as our auditors for the fiscal year ending December 31, 2018.2023. Deloitte & Touche LLP acted as the independent registered public accounting firm for Syndax since 2008. A representative of Deloitte & Touche LLP is expected to be presentavailable at the Annual Meeting with the opportunity to make a statement if he or she desires and to respond to appropriate questions.

The Company’s organizational documents do not require that the stockholders ratify the selection of Deloitte & Touche LLP as the Company’s independent registered public accounting firm. SyndaxThe Company requests such ratification as a matter of good corporate practice. The selection of Deloitte & Touche LLP as our independent registered public accounting firm will be ratified if the votes cast FOR exceed the votes cast AGAINST the proposal. Brokers, bankers and other nominees have discretionary voting power on this routine matter. Abstentions and broker non-votes will have no effect on Proposal 2. If the stockholders do not ratify the selection, the Audit Committee will reconsider whether to retain Deloitte & Touche LLP, but still may retain this firm. Even if the selection is ratified, the Audit Committee, in its discretion, may change the appointment at any time during the year if it determines that such a change would be in the best interests of Syndax and its stockholders.

Vote Required

The affirmative vote of the holders of a majority of the voting power of the shares present in person or represented by proxy and entitled to vote on the matter at the Annual Meeting will be required to ratify the selection of Deloitte & Touche LLP. Abstentions will have the same effect as a vote “AGAINST” this proposal.

Pre-Approval Policies and Procedures

Our Audit Committee approves all audit and pre-approves all non-audit services provided by Deloitte & Touche LLP before it is engaged by us to render non-audit services. These services may include audit-related services, tax services and other services.

The pre-approval requirement set forth above does not apply with respect to non-audit services if:

Independent Registered Public Accounting Firm Fees

The following is a summary and description of fees incurred by Deloitte & Touche LLP for the fiscal years ended December 31, 20172022 and 2016:2021. All fees described below were pre-approved by the Audit Committee.