SNDX / Syndax Pharmaceuticals, Inc. - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

FORM 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 04, 2025 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commi

Second Quarter 2025 Financial Results Presentation / August 4, 2025

Second Quarter 2025 Financial Results Presentation / August 4, 2025 Forward-looking statements disclosure This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995.

Syndax Reports Second Quarter 2025 Financial Results and Provides Business Update • $28.6 million of Revuforj® (revumenib) net revenue, representing 43% growth over 1Q25 – • $36.2 million of Niktimvo™ (axatilimab-csfr) net revenue reported by Incyte

Exhibit 99.1 Syndax Reports Second Quarter 2025 Financial Results and Provides Business Update • $28.6 million of Revuforj® (revumenib) net revenue, representing 43% growth over 1Q25 – • $36.2 million of Niktimvo™ (axatilimab-csfr) net revenue reported by Incyte in first full quarter of launch;$9.4 million in collaboration revenue reported by Syndax – – sNDA in R/R mNPM1 AML granted Priority Revie

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Pha

FORM 8-K Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 24, 2025 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commiss

Syndax Pharmaceuticals Appoints Dr. Nicholas Botwood as Head of Research and Development and Chief Medical Officer

Exhibit 99.1 Syndax Pharmaceuticals Appoints Dr. Nicholas Botwood as Head of Research and Development and Chief Medical Officer - Dr. Nicholas Botwood comes to Syndax from BMS and brings 25 years of industry experience leading drug development, R&D strategy and global commercialization of novel oncology therapeutics - NEW YORK, May 12, 2025 (GLOBE NEWSWIRE) - Syndax Pharmaceuticals (Nasdaq: SNDX),

Employment Agreement, dated May 12, 2025, by and between the Company and Dr. Nicholas Botwood

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of the 12th day of May, 2025 (the “Execution Date”), between NICHOLAS A.J. BOTWOOD BSC (HONS), MB BS, MFPM, FRCP (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Company is a b

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 12, 2025 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

Financial Statements and Exhibits, Results of Operations and Financial Condition, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 05, 2025 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Ph

Syndax Reports First Quarter 2025 Financial Results and Provides Business Update • $20.0 million in Revuforj® (revumenib) net revenue in first full quarter of launch – • $13.6 million in Niktimvo™ (axatilimab-csfr) net revenue (reported by Incyte) in

Exhibit 99.1 Syndax Reports First Quarter 2025 Financial Results and Provides Business Update • $20.0 million in Revuforj® (revumenib) net revenue in first full quarter of launch – • $13.6 million in Niktimvo™ (axatilimab-csfr) net revenue (reported by Incyte) in first partial quarter of launch – – Submitted sNDA for revumenib in R/R mNPM1 AML – • Initiated a pivotal frontline trial of revumenib p

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

Calculation of Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Syndax Pharmaceuticals, Inc.

As filed with the Securities and Exchange Commission on March 4, 2025

As filed with the Securities and Exchange Commission on March 4, 2025 Registration No.

Syndax Reports Fourth Quarter and Full Year 2024 Financial Results and Provides Business Update • $7.7 million in Revuforj® (revumenib) net product revenue in initial five weeks of launch – • Launched Niktimvo™ (axatilimab-csfr) in the U.S. in late J

Exhibit 99.1 Syndax Reports Fourth Quarter and Full Year 2024 Financial Results and Provides Business Update • $7.7 million in Revuforj® (revumenib) net product revenue in initial five weeks of launch – • Launched Niktimvo™ (axatilimab-csfr) in the U.S. in late January, in partnership with Incyte – – sNDA filing for revumenib in R/R mNPM1 AML expected in 2Q25 based on positive pivotal data from AU

Subsidiaries of the Registrant.

Exhibit 21.1 SUBSIDIARIES OF SYNDAX PHARMACEUTICALS, INC. Name Jurisdiction of Incorporation Syndax Securities Corporation Massachusetts Syndax Europe B.V. Netherlands

6884,826,632 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

6884,826,632 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-37708 S

Purchase and Sale Agreement by and between the Company and with Royalty Pharma Development Funding, LLC, dated November 4, 2024.

Exhibit 10.43 ` Certain information marked as [***] has been excluded from this exhibit because it is both (i) not material and (ii) is the type that the Registrant treats as private or confidential. Purchase And Sale Agreement By and Between Syndax Pharmaceuticals, Inc. and Royalty Pharma Development Funding, LLC Dated as of November 4, 2024 Table of Contents Page Article 1 DEFINITIONS 1 Section

Insider Trading Policy.

Exhibit 19.1 Syndax Pharmaceuticals, Inc. Insider Trading Policy Policy Principles • Employees, directors, other applicable members of management and designated consultants (each a “Covered Person,” and collectively, “Covered Persons”) of Syndax Pharmaceuticals, Inc. and its subsidiaries (together, the “Company”) are responsible for understanding the obligations that come with having access to mat

Description of Capital Stock.

Exhibit 4.3 DESCRIPTION OF CAPITAL STOCK The following description of our capital stock and provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries. You should also refer to the amended and restated certificate of incorporation and the amended and restated bylaws, which are included as an exhibit to our Annual Report on Form 10-K. All refer

Non-employee Director Compensation Policy, as amended, dated as of February 5, 2025.

Exhibit 10.28 SYNDAX PHARMACEUTICALS, INC. AMENDED & RESTATED NON-EMPLOYEE DIRECTOR COMPENSATION POLICY Effective: February 5, 2025 Each member of the Board of Directors (the “Board”) who is not also serving as an employee of Syndax Pharmaceuticals, Inc. (the “Company”) or any of its subsidiaries will receive the compensation described in this Amended and Restated Non-Employee Director Compensatio

Syndax Pharmaceuticals, Inc. 2023 Inducement Plan, as amended.

Exhibit 10.16 SYNDAX PHARMACEUTICALS, INC. 2023 INDUCEMENT PLAN As Amended: December 6, 2023, July 22, 2024, December 19, 2024 Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), sets forth herein the terms of its 2023 Inducement Plan (the “Plan”), as follows: 1. GENERAL 1.1 Purpose. This Plan is intended to provide (a) an inducement material for certain individuals to enter into

Financial Statements and Exhibits, Results of Operations and Financial Condition, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 03, 2025 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commis

JOINT ACQUISITION STATEMENT PURSUANT TO RULE 13d-1(k)

EXHIBIT 99.1 JOINT ACQUISITION STATEMENT PURSUANT TO RULE 13d-1(k) The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 20, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 15, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Syndax Announces FDA Approval of Revuforj® (revumenib), the First and Only Menin Inhibitor to Treat Adult and Pediatric Patients with Relapsed or Refractory Acute Leukemia with a KMT2A Translocation – Approval based on positive data from the AUGMENT-

Exhibit 99.1 Syndax Announces FDA Approval of Revuforj® (revumenib), the First and Only Menin Inhibitor to Treat Adult and Pediatric Patients with Relapsed or Refractory Acute Leukemia with a KMT2A Translocation – Approval based on positive data from the AUGMENT-101 clinical trial, in which Revuforj delivered robust and durable rates of remission in R/R acute leukemia patients with a KMT2A translo

Syndax Announces Positive Pivotal Topline Results from Relapsed or Refractory mNPM1 AML Cohort in AUGMENT-101 Trial of Revumenib – Primary endpoint met with CR/CRh rate of 23% in pivotal Ph 2 cohort of R/R mNPM1 AML patients (p-value = 0.0014) – – 47

Exhibit 99.1 Syndax Announces Positive Pivotal Topline Results from Relapsed or Refractory mNPM1 AML Cohort in AUGMENT-101 Trial of Revumenib – Primary endpoint met with CR/CRh rate of 23% in pivotal Ph 2 cohort of R/R mNPM1 AML patients (p-value = 0.0014) – – 47% (30/64) ORR in a heavily pre-treated population, including 75% with prior venetoclax exposure in the efficacy population – – Favorable

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 12, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

JOINT FILING AGREEMENT

EX-99 2 Rule13DJointFilingAgreement.htm JOINT FILING AGREEMENT JOINT FILING AGREEMENT The undersigned hereby agree that this Schedule 13G (the “Schedule 13G”) with respect to the common stock of Syndax Pharmaceuticals, Inc. is, and any additional amendment thereto signed by each of the undersigned shall be, filed on behalf of each undersigned pursuant to and in accordance with the provisions of 13

SNDX / Syndax Pharmaceuticals, Inc. / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

SC 13G/A 1 SEC13GFiling.htm SEC SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2 )* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) September 30, 2024 (Date of Event Which Requires Filing of this Statement) Check the appropri

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Synda

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 05, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Syndax Reports Third Quarter 2024 Financial Results and Provides Business Update

Exhibit 99.1 Syndax Reports Third Quarter 2024 Financial Results and Provides Business Update – New revumenib and Niktimvo™clinical data will be highlighted at 66th ASH Annual Meeting – – mNPM1 AML topline data from AUGMENT-101 expected in 4Q24; potential sNDA filing in 1H25 – – Revumenib NDA in R/R KMT2Ar acute leukemia is being reviewed under RTOR; PDUFA action date of December 26, 2024 – – Nikt

Entry into a Material Definitive Agreement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 04, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

SNDX / Syndax Pharmaceuticals, Inc. / STATE STREET CORP Passive Investment

SC 13G/A 1 SyndaxPharmaceuticalsInc.htm SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* SYNDAX PHARMACEUTICALS INC (Name of Issuer) COMMON STOCK (Title of Class of Securities) 87164F105 (CUSIP Number) September 30, 2024 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate th

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 01, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commi

Syndax Reports Second Quarter 2024 Financial Results and Provides Clinical and Business Update – Axatilimab BLA in refractory chronic GVHD is under Priority Review; PDUFA action date of August 28, 2024 – – Revumenib NDA in R/R KMT2Ar acute leukemia i

Exhibit 99.1 Syndax Reports Second Quarter 2024 Financial Results and Provides Clinical and Business Update – Axatilimab BLA in refractory chronic GVHD is under Priority Review; PDUFA action date of August 28, 2024 – – Revumenib NDA in R/R KMT2Ar acute leukemia is being reviewed under RTOR; PDUFA action date of December 26, 2024 – – Pivotal AUGMENT-101 topline data from the mNPM1 AML cohort expect

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Pha

Syndax Pharmaceuticals Appoints Aleksandra Rizo, M.D., Ph.D. to the Board of Directors

Exhibit 99.1 Syndax Pharmaceuticals Appoints Aleksandra Rizo, M.D., Ph.D. to the Board of Directors WALTHAM, Mass., May 15, 2024 /PRNewswire/ - Syndax Pharmaceuticals (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the appointment of Aleksandra Rizo, M.D., Ph.D., to its Board of Directors. Dr. Rizo has extensive clin

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 14, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

Syndax Pharmaceuticals Reports First Quarter 2024 Financial Results and Provides Clinical and Business Update – NDA filing for revumenib in R/R KMT2Ar acute leukemia granted Priority Review under RTOR; PDUFA action date set for September 26, 2024 – –

Exhibit 99.1 Syndax Pharmaceuticals Reports First Quarter 2024 Financial Results and Provides Clinical and Business Update – NDA filing for revumenib in R/R KMT2Ar acute leukemia granted Priority Review under RTOR; PDUFA action date set for September 26, 2024 – – BLA filing for axatilimab in chronic GVHD granted Priority Review; PDUFA action date set for August 28, 2024 – – Enrollment completed in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Ph

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 08, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 15, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commis

Syndax Announces Appointment of Steven Closter as Chief Commercial Officer – Steven Closter brings more than 30 years of commercial experience in the biopharmaceutical industry to Syndax – – Company on track for two potential first- and best-in-class

Exhibit 99.1 Syndax Announces Appointment of Steven Closter as Chief Commercial Officer – Steven Closter brings more than 30 years of commercial experience in the biopharmaceutical industry to Syndax – – Company on track for two potential first- and best-in-class product launches in 2024 – WALTHAM, Mass., March 18, 2024 (PRNEWSWIRE) – Syndax Pharmaceuticals (Nasdaq: SNDX), a clinical stage biophar

Employment Agreement, dated March 18, 2024, by and between the Company and Steven Closter

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of the 18th day of March, 2024 (the “Execution Date”), between STEVEN CLOSTER (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Company is a biopharmaceutical company. B. The Co

Syndax Pharmaceuticals, Inc. 2023 Inducement Plan.

Exhibit 10.16 SYNDAX PHARMACEUTICALS, INC. 2023 INDUCEMENT PLAN As Amended: December 6, 2023 Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), sets forth herein the terms of its 2023 Inducement Plan (the “Plan”), as follows: 1. GENERAL 1.1 Purpose. This Plan is intended to provide (a) an inducement material for certain individuals to enter into employment with the Company withi

Form of Debt Securities Warrant Agreement and Warrant Certificate.

Exhibit 4.10 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF DEBT SECURITIES WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF DEBT SECURITIES WARRANT AGREEMENT THIS DEBT SECURITIES WARRANT AGREEMENT (this “Agreement”), dated as of [•], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and [•], a [corporation] [national banking association]

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) Syndax Pharmaceuticals, Inc.

As filed with the Securities and Exchange Commission on February 27, 2024

As filed with the Securities and Exchange Commission on February 27, 2024 Registration No.

Form of Preferred Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.9 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF PREFERRED STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF PREFERRED STOCK WARRANT AGREEMENT THIS PREFERRED STOCK WARRANT AGREEMENT (this “Agreement”), dated as of [•], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and [•], a [corporation] [national banking association] o

Amendment to Executive Employment by and between the Company and Keith A. Goldan, dated as of February 26, 2024.

Exhibit 10.27 AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT This AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT (this “Amendment”) is entered into as of the 26th day of February, 2024 (the “Execution Date”), between KEITH A. GOLDAN (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”) and supplements the terms of that certain executive employment agreement by and between the Parties, dated as

84,826,632 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

84,826,632 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-37708 Syn

Amendment to Amended and Restated Executive Employment by and between the Company and Luke J. Albrecht, dated as of February 26, 2024.

Exhibit 10.23 AMENDMENT TO AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDMENT TO AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this “Amendment”) is entered into as of the 26th day of February, 2024 (the “Execution Date”), between LUKE J. ALBRECHT (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”) and supplements the terms of that certain amended and restated exec

Non-employee Director Compensation Policy, as amended, dated as of February 7, 2024.

Exhibit 10.31 SYNDAX PHARMACEUTICALS, INC. AMENDED & RESTATED NON-EMPLOYEE DIRECTOR COMPENSATION POLICY Effective: February 7, 2024 Each member of the Board of Directors (the “Board”) who is not also serving as an employee of Syndax Pharmaceuticals, Inc. (the “Company”) or any of its subsidiaries will receive the compensation described in this Amended and Restated Non-Employee Director Compensatio

Form of Common Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.8 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF COMMON STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF COMMON STOCK WARRANT AGREEMENT THIS COMMON STOCK WARRANT AGREEMENT (this “Agreement”), dated as of [•], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and [•], a [corporation] [national banking association] organized

Form of Indenture, between the Company and one or more trustees to be named.

Exhibit 4.6 SYNDAX PHARMACEUTICALS, INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [•], 20 Debt Securities TABLE OF CONTENTS PAGE ARTICLE 1 DEFINITIONS 1 Section 1.01 Definitions of Terms 1 ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 5 Section 2.01 Designation and Terms of Securities 5 Section 2.02 Form of Securities and Trustee’s Certificate

Amendment to Executive Employment by and between the Company and Neil Gallagher, M.D., Ph.D., dated as of February 26, 2024.

Exhibit 10.30 AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT This AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT (this “Amendment”) is entered into as of the 26th day of February, 2024 (the “Execution Date”), between NEIL GALLAGHER, M.D., Ph.D. (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”) and supplements the terms of that certain executive employment agreement by and between the Partie

Syndax Pharmaceuticals Reports Fourth Quarter and Full Year 2023 Financial Results and Provides Clinical and Business Update – BLA filing for axatilimab in chronic GVHD granted Priority Review; PDUFA action date set for August 28, 2024 – – NDA for re

Exhibit 99.1 Syndax Pharmaceuticals Reports Fourth Quarter and Full Year 2023 Financial Results and Provides Clinical and Business Update – BLA filing for axatilimab in chronic GVHD granted Priority Review; PDUFA action date set for August 28, 2024 – – NDA for revumenib in R/R KMT2Ar acute leukemia submitted under FDA’s RTOR program; PDUFA date assignment expected in 1Q24 – – Enrollment in AUGMENT

Amendment to Executive Employment by and between the Company and Catherine Madigan, M.D., dated as of February 26, 2024.

Exhibit 10.25 AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT This AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT (this “Amendment”) is entered into as of the 26th day of February, 2024 (the “Execution Date”), between CATHERINE MADIGAN, M.D. (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”) and supplements the terms of that certain executive employment agreement by and between the Parties, d

As filed with the Securities and Exchange Commission on February 27, 2024

Table of Contents As filed with the Securities and Exchange Commission on February 27, 2024 Registration No.

Calculation of Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Syndax Pharmaceuticals, Inc.

Amended and Restated Executive Employment Agreement by and between the Company and Luke J. Albrecht, dated as of April 27, 2020.

Exhibit 10.22 AMENDED & RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of the 27th day of April, 2020 (the “Effective Date”), between LUKE J. ALBRECHT (“Executive”) and SYNDAX PHARMACEUTICALS, INC. (the “Company”). Certain capitalized terms used in this Agreement are defined in Article 6. RECITALS A. The Compan

Amendment to Amended and Restated Executive Employment by and between the Company and Michael A. Metzger, dated as of February 26, 2024.

Exhibit 10.20 AMENDMENT TO AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDMENT TO AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this “Amendment”) is entered into as of the 26th day of February, 2024 (the “Execution Date”), between MICHAEL A. METZGER (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”) and supplements the terms of that certain amended and restated ex

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 27, 2024 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Incentive Compensation Recoupment Policy.

Exhibit 97 Syndax Pharmaceuticals, Inc. Incentive Compensation Recoupment Policy 1. Introduction The Compensation Committee (the “Compensation Committee”) of the Board of Directors (the “Board”) of Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), has determined that it is in the best interests of the Company and its stockholders to adopt this Incentive Compensation Recoupment

Description of Capital Stock.

Exhibit 4.3 DESCRIPTION OF CAPITAL STOCK The following description of our capital stock and provisions of our amended and restated certificate of incorporation and amended and restated bylaws are summaries. You should also refer to the amended and restated certificate of incorporation and the amended and restated bylaws, which are included as an exhibit to our Annual Report on Form 10-K. All refer

SNDX / Syndax Pharmaceuticals, Inc. / Kynam Capital Management, LP - KYNAM CAPITAL MANAGEMENT, LP Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 Syndax Pharmaceuticals Inc (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2023 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant

SNDX / Syndax Pharmaceuticals, Inc. / Point72 Asset Management, L.P. - SYNDAX PHARMACEUTICALS, INC. Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule

SNDX / Syndax Pharmaceuticals, Inc. / VANGUARD GROUP INC - SCHEDULE 13G Passive Investment

SC 13G 1 tv02028-syndaxpharmaceutical.htm SCHEDULE 13G SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 Name of issuer: Syndax Pharmaceuticals Inc Title of Class of Securities: Common Stock CUSIP Number: 87164F105 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the appropriate box to designate the rule p

SNDX / Syndax Pharmaceuticals, Inc. / Avidity Partners Management LP Passive Investment

SC 13G/A 1 d1097879313g-a.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 5)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check th

SNDX / Syndax Pharmaceuticals, Inc. / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

SC 13G/A 1 SEC13GFiling.htm SEC SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1 )* Syndax Pharmaceuticals Inc (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 29, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 19, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Syndax Announces Closing of Public Offering of Common Stock and Exercise in Full of the Underwriters' Option to Purchase Additional Shares

Exhibit 99.1 Syndax Announces Closing of Public Offering of Common Stock and Exercise in Full of the Underwriters' Option to Purchase Additional Shares WALTHAM, Mass., December 19, 2023 /PRNewswire/ - Syndax Pharmaceuticals, Inc. (“Syndax,” the “Company” or “we”) (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the cl

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 14, 2023 SYNDAX PHARMACE

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 14, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

Calculation of Filing Fee Tables (Form Type) Syndax Pharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forwar

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Tables 424(b)(5) (Form Type) Syndax Pharmaceuticals, Inc.

Underwriting Agreement, dated December 14, 2023, by and between the Company and Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC and Cowen and Company, LLC.

EX-1.1 Exhibit 1.1 10,810,810 Shares SYNDAX PHARMACEUTICALS, INC. COMMON STOCK (PAR VALUE $0.0001 PER SHARE) UNDERWRITING AGREEMENT December 14, 2023 December 14, 2023 Goldman Sachs & Co. LLC J.P. Morgan Securities LLC Cowen and Company, LLC c/o Goldman Sachs & Co. LLC 200 West Street New York, New York 10282-2198 c/o J.P. Morgan Securities LLC 383 Madison Avenue New York, New York 10179 c/o Cowen

10,810,810 Shares of Common Stock

Table of Contents Filed pursuant to Rule 424(b)(5) Registration No. 333-254661 PROSPECTUS SUPPLEMENT (to Prospectus dated March 24, 2021) 10,810,810 Shares of Common Stock We are offering 10,810,810 shares of our common stock pursuant to this prospectus supplement. Our common stock is listed on The Nasdaq Global Select Market under the symbol “SNDX.” On December 14, 2023, the last reported sale pr

SUBJECT TO COMPLETION, DATED DECEMBER 14, 2023

424B5 Table of Contents The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed.

Syndax Announces Positive Data for Revumenib in Patients with Acute Leukemias from the BEAT AML, SAVE AML and AUGMENT-102 Phase 1 Combination Trials - Data collectively highlight revumenib's combination potential with current standard of care agents

Exhibit 99.2 Syndax Announces Positive Data for Revumenib in Patients with Acute Leukemias from the BEAT AML, SAVE AML and AUGMENT-102 Phase 1 Combination Trials - Data collectively highlight revumenib's combination potential with current standard of care agents and support advancement into pivotal combination trials in the frontline setting - - 100% CRc observed in BEAT AML trial exploring revume

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 10, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Syndax Presents Positive Data from Pivotal AUGMENT-101 Trial of Revumenib in Relapsed/Refractory KMT2Ar Acute Leukemia at Late-Breaking Oral Presentation During 65th ASH Annual Meeting – Pivotal AUGMENT-101 trial met its primary endpoint at interim a

Exhibit 99.3 Syndax Presents Positive Data from Pivotal AUGMENT-101 Trial of Revumenib in Relapsed/Refractory KMT2Ar Acute Leukemia at Late-Breaking Oral Presentation During 65th ASH Annual Meeting – Pivotal AUGMENT-101 trial met its primary endpoint at interim analysis of the pooled KMT2Ar AML and ALL cohorts (p-value = 0.0036); CR/CRh rate consistent across adult and pediatric patients– – 63% ov

Incyte and Syndax Present Additional Data from Positive AGAVE-201 Trial at ASH Plenary Session Showing Axatilimab Efficacy Including Durable Responses in Chronic Graft-Versus-Host Disease  Trial met its primary endpoint across all dose cohorts with

Exhibit 99.1 Incyte and Syndax Present Additional Data from Positive AGAVE-201 Trial at ASH Plenary Session Showing Axatilimab Efficacy Including Durable Responses in Chronic Graft-Versus-Host Disease  Trial met its primary endpoint across all dose cohorts with 74% of patients at the 0.3 mg/kg dose achieving a complete or partial response within the first six months of treatment  Data are featur

* * * * *

Syndax Pharmaceuticals, Inc. 730 Third Avenue, 9th Floor New York, NY 10017 35 Gatehouse Drive Building D, Floor 3 Waltham, MA 02451 www.syndax.com VIA EDGAR November 28, 2023 United States Securities and Exchange Commission Division of Corporation Finance Office of Life Sciences 100 F Street, N.E. Washington, D.C. 20549 Attn: Eric Atallah Daniel Gordon Re: Syndax Pharmaceuticals, Inc. Form 10K fo

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Synda

Syndax Pharmaceuticals Reports Third Quarter 2023 Financial Results and Provides Clinical and Business Update – NDA submission initiated for revumenib in R/R KMT2Ar acute leukemia under RTOR – – mNPM1 final efficacy data from the Phase 1 portion of A

Exhibit 99.1 Syndax Pharmaceuticals Reports Third Quarter 2023 Financial Results and Provides Clinical and Business Update – NDA submission initiated for revumenib in R/R KMT2Ar acute leukemia under RTOR – – mNPM1 final efficacy data from the Phase 1 portion of AUGMENT-101 demonstrates a 36% CR/CRh rate – – Revumenib and axatilimab U.S. registrational filings on track for year-end 2023 completion

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 02, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

SNDX / Syndax Pharmaceuticals Inc / Point72 Asset Management, L.P. - SYNDAX PHARMACEUTICALS INC Passive Investment

SC 13G 1 p23-2675sc13g.htm SYNDAX PHARMACEUTICALS INC SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) October 30, 2023 (Date of Event Which Requires Filing of this Statement

JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)

EX-99.1 2 p23-2675exhibit99.htm JOINT FILING AGREEMENT EXHIBIT 99.1 JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k) The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G shall be filed on behalf of each of the undersigned without the necessity of filing a

AGREEMENT

EX-99.A 2 d542507dex99a.htm EX-99.A EXHIBIT A AGREEMENT Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of Common Stock of Syndax Pharmaceuticals, Inc. Date: October 5, 2023 FRAZIER LIFE SCIENCES PUBL

SNDX / Syndax Pharmaceuticals Inc / Frazier Life Sciences Public Fund, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 d542507dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 2)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) October 3, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to d

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 02, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Comm

Syndax Announces Pivotal AUGMENT-101 Trial of Revumenib in Relapsed/Refractory KMT2Ar Acute Leukemia Meets Primary Endpoint and Stopped Early for Efficacy Following Protocol-Defined Interim Analysis – Trial met its primary endpoint with a CR/CRh rate

Exhibit 99.1 Syndax Announces Pivotal AUGMENT-101 Trial of Revumenib in Relapsed/Refractory KMT2Ar Acute Leukemia Meets Primary Endpoint and Stopped Early for Efficacy Following Protocol-Defined Interim Analysis – Trial met its primary endpoint with a CR/CRh rate of 23% at interim analysis of the pooled KMT2Ar AML and ALL cohorts (p-value = 0.0036); an additional 14% of patients proceeded to trans

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 03, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commi

Syndax Pharmaceuticals Reports Second Quarter 2023 Financial Results and Provides Clinical and Business Update – Announced positive topline results from the pivotal AGAVE-201 trial of axatilimab in cGVHD – – Topline data from the pivotal AUGMENT-101

Syndax Pharmaceuticals Reports Second Quarter 2023 Financial Results and Provides Clinical and Business Update – Announced positive topline results from the pivotal AGAVE-201 trial of axatilimab in cGVHD – – Topline data from the pivotal AUGMENT-101 trial of revumenib in KMT2Ar acute leukemia on track for the third quarter of 2023 – – Two U.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Pha

Syndax and Incyte Announce Positive Topline Results from the Pivotal AGAVE-201 Trial of Axatilimab in Chronic Graft-Versus-Host Disease – Trial met its primary endpoint across all cohorts with an overall response rate (ORR) of 74% at a dose of 0.3 mg

Exhibit 99.1 FOR IMMEDIATE RELEASE Syndax and Incyte Announce Positive Topline Results from the Pivotal AGAVE-201 Trial of Axatilimab in Chronic Graft-Versus-Host Disease – Trial met its primary endpoint across all cohorts with an overall response rate (ORR) of 74% at a dose of 0.3 mg/kg administered every two weeks – – Data highlight durable response to treatment. At the 0.3 mg/kg dose, 60% of pa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): July 24, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commiss

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 26, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

Sales Agreement dated as of May 26, 2023, between the Registrant and Cowen and Company, LLC (incorporated herein by reference to Exhibit 1.1 to the Registrant’s Current Report on Form 8-K (File No. 001-37708), filed with the SEC on May 26, 2023).

Exhibit 1.1 SYNDAX PHARMACEUTICALS, INC. common Stock (par value $0.0001 per share) SALES AGREEMENT May 26, 2023 Cowen and Company, LLC 599 Lexington Avenue New York, NY 10022 Ladies and Gentlemen: Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), confirms its agreement (this “Agreement”) with Cowen and Company, LLC (“Cowen”), as follows: 1. Issuance and Sale of Shares. The Com

You’ve Exceeded the SEC’s Traffic Limit

EX-FILING FEES Exhibit 107 Calculation of Filing Fee Tables 424(b)(5) (Form Type) Syndax Pharmaceuticals, Inc.

Common Stock

424B5 Table of Contents PROSPECTUS SUPPLEMENT (To Prospectus dated March 24, 2021) Filed Pursuant to Rule 424(b)(5) Registration No.

Certificate of Amendment to the Amended and Restated Certificate of Incorporation of the Company (incorporated herein by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on May 18, 2023).

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF SYNDAX PHARMACEUTICALS, INC. Syndax Pharmaceuticals, Inc., a corporation organized and existing under the General Corporation Law of the State of Delaware, does hereby certify as follows: First: The name of the Corporation is Syndax Pharmaceuticals, Inc. Second: The date of filing the original Certific

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 17, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 05, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commissi

Syndax Pharmaceuticals Reports First Quarter 2023 Financial Results and Provides Clinical and Business Update – Topline data from the pivotal AGAVE-201 trial of axatilimab in cGVHD on track for mid-2023 – – Topline data from the pivotal AUGMENT-101 t

Syndax Pharmaceuticals Reports First Quarter 2023 Financial Results and Provides Clinical and Business Update – Topline data from the pivotal AGAVE-201 trial of axatilimab in cGVHD on track for mid-2023 – – Topline data from the pivotal AUGMENT-101 trial of revumenib in KMT2Ar acute leukemia on track for the third quarter of 2023 – – Two U.

Form of Restricted Stock Unit Agreement pursuant to the Syndax Pharmaceuticals, Inc. 2023 Inducement Plan (incorporated herein by reference to Exhibit 10.2 to the Company’s Quarterly Report on Form 10-Q (File No. 001-37708), as filed with the SEC on May 8, 2023).

Exhibit 10.2 SYNDAX PHARMACEUTICALS, INC. 2023 INDUCEMENT PLAN STOCK UNIT AGREEMENT Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), hereby grants Stock Units denominated in shares of its common stock, par value $0.0001 per share (this “Award”), to the Grantee named below, subject to the vesting and other conditions set forth below. Additional terms and conditions of this Awar

Form 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Ph

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

DEFA14A 1 sndx-2023-04-18-defa14a.htm DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission On

Definitive Proxy Statement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

Syndax Pharmaceuticals Announces Appointment of Neil Gallagher, M.D., Ph.D. as President, Head of Research and Development - Neil Gallagher, M.D., Ph.D. brings to Syndax over 20 years of experience as a leading oncology drug developer -

Exhibit 99.1 Syndax Pharmaceuticals Announces Appointment of Neil Gallagher, M.D., Ph.D. as President, Head of Research and Development - Neil Gallagher, M.D., Ph.D. brings to Syndax over 20 years of experience as a leading oncology drug developer - WALTHAM, Mass., March 30, 2023 /PRNewswire/ - Syndax Pharmaceuticals, Inc. (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 29, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commis

Executive Employment Agreement by and between the Company and Neil Gallagher, M.D., Ph.D., dated as of March 30, 2023 (incorporated herein by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on March 30, 2023).

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of the 30th day of March, 2023 (the “Execution Date”), between NEIL GALLAGHER, M.D., Ph.D. (“Executive”) and Syndax Pharmaceuticals, Inc. (the “Company”). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Company is a biopharmaceutical compa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant  Filed by a party other than the Registrant  Check the appropriate box:  Preliminary Proxy Statement  Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))  Defini

Calculation of Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Syndax Pharmaceuticals, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 28, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Subsidiaries of the Registrant.

Exhibit 21.1 SUBSIDIARIES OF SYNDAX PHARMACEUTICALS, INC. Name Jurisdiction of Incorporation Syndax Securities Corporation Massachusetts Syndax Limited United Kingdom Syndax Europe B.V. Netherlands

Form 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-37708 Syndax Pharmac

Non-employee Director Compensation Policy, as amended, dated as of February 2, 2023.

Exhibit 10.24 SYNDAX PHARMACEUTICALS, INC. AMENDED & RESTATED NON-EMPLOYEE DIRECTOR COMPENSATION POLICY Effective: February 2, 2023 Each member of the Board of Directors (the “Board”) who is not also serving as an employee of Syndax Pharmaceuticals, Inc. (the “Company”) or any of its subsidiaries will receive the compensation described in this Amended and Restated Non-Employee Director Compensatio

Syndax Pharmaceuticals Reports Fourth Quarter and Full Year 2022 Financial Results and Provides Clinical and Business Update – Topline data from AUGMENT-101 KMT2Ar patients expected in the third quarter of 2023 – – Topline data from the pivotal AGAVE

Syndax Pharmaceuticals Reports Fourth Quarter and Full Year 2022 Financial Results and Provides Clinical and Business Update – Topline data from AUGMENT-101 KMT2Ar patients expected in the third quarter of 2023 – – Topline data from the pivotal AGAVE-201 trial on track for mid-2023 – – Two U.

As filed with the Securities and Exchange Commission on February 28, 2023

As filed with the Securities and Exchange Commission on February 28, 2023 Registration No.

SNDX / Syndax Pharmaceuticals Inc / Avidity Partners Management LP Passive Investment

SC 13G/A 1 d994249913g-a.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 4)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Statement) Check the

SNDX / Syndax Pharmaceuticals Inc / Nantahala Capital Management, LLC - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which

SNDX / Syndax Pharmaceuticals Inc / Frazier Life Sciences Public Fund, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 d412263dsc13ga.htm SC 13G/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the

AGREEMENT

EX-99.A 2 d412263dex99a.htm EX-99.A EXHIBIT A AGREEMENT Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of Common Stock of Syndax Pharmaceuticals, Inc. Date: February 14, 2023 FRAZIER LIFE SCIENCES PU

SNDX / Syndax Pharmaceuticals Inc / BIOTECHNOLOGY VALUE FUND L P - AMENDMENT NO. 7 TO THE SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 7)1 Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Nu

Syndax Pharmaceuticals, Inc. 2023 Inducement Plan.

Exhibit 10.1 SYNDAX PHARMACEUTICALS, INC. 2023 INDUCEMENT PLAN Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”), sets forth herein the terms of its 2023 Inducement Plan (the “Plan”), as follows: 1. GENERAL 1.1 Purpose. This Plan is intended to provide (a) an inducement material for certain individuals to enter into employment with the Company within the meaning of Rule 5635(c)(

Form of Option Agreement pursuant to the Syndax Pharmaceuticals, Inc. 2023 Inducement Plan (incorporated herein by reference to Exhibit 10.2 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on February 8, 2023).

Exhibit 10.2 SynDax Pharmaceuticals, Inc. 2023 Inducement PLAN NONQUALIFIED OPTION AGREEMENT Syndax Pharmaceuticals, Inc., a Delaware corporation (the “Company”) hereby grants an option to purchase shares of its common stock, par value $0.0001 per share (the “Option”), to the optionee named below, subject to the vesting and other conditions set forth below. Additional terms and conditions of the g

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 02, 2023 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

SNDX / Syndax Pharmaceuticals Inc / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

SC 13G 1 SEC13GFiling.htm SEC SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals Inc (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 30, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 14, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Syndax Announces Closing of Public Offering of Common Stock and Full Exercise of Underwriters' Option to Purchase Additional Shares

Exhibit 99.1 Syndax Announces Closing of Public Offering of Common Stock and Full Exercise of Underwriters' Option to Purchase Additional Shares WALTHAM, Mass., December 14, 2022 (PRNEWSWIRE) ? Syndax Pharmaceuticals, Inc. ("Syndax," the "Company" or "we") (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the closing o

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 6, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Comm

Underwriting Agreement, dated December 6, 2022, by and between the Company and Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC and Cowen and Company, LLC.

Exhibit 1.1 6,818,182 Shares SYNDAX PHARMACEUTICALS, INC. COMMON STOCK (PAR VALUE $0.0001 PER SHARE) UNDERWRITING AGREEMENT December 6, 2022 December 6, 2022 Goldman Sachs & Co. LLC J.P. Morgan Securities LLC Cowen and Company, LLC c/o Goldman Sachs & Co. LLC 200 West Street New York, New York 10282-2198 c/o J.P. Morgan Securities LLC 383 Madison Avenue New York, New York 10179 c/o Cowen and Compa

6,818,182 Shares of Common Stock

Table of Contents Filed pursuant to Rule 424(b)(5) Registration No. 333-254661 PROSPECTUS SUPPLEMENT (to Prospectus dated March 24, 2021) 6,818,182 Shares of Common Stock We are offering 6,818,182 shares of our common stock pursuant to this prospectus supplement. Our common stock is listed on The Nasdaq Global Select Market under the symbol ?SNDX.? On December 6, 2022, the last reported sale price

Calculation of Filing Fee Tables (Form Type) Syndax Pharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forwar

Exhibit 107 Calculation of Filing Fee Tables 424(b)(5) (Form Type) Syndax Pharmaceuticals, Inc.

SUBJECT TO COMPLETION, DATED DECEMBER 6, 2022

Table of Contents The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed.

Syndax Pharmaceuticals Announces Appointment of Steve Sabus as Chief Commercial Officer

Exhibit 99.1 Syndax Pharmaceuticals Announces Appointment of Steve Sabus as Chief Commercial Officer WALTHAM, Mass., December 2, 2022 /PRNewswire/ - Syndax Pharmaceuticals, Inc. (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the appointment of Steve Sabus to the role of Chief Commercial Officer, effective December 5

Executive Employment Agreement by and between the Company and Steve M. Sabus, dated as of December 1, 2022 (incorporated herein by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on December 5, 2022).

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 1st day of December, 2022 (the ?Execution Date?), between STEVE M. SABUS (?Executive?) and Syndax Pharmaceuticals, Inc. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Company is a biopharmaceutical company. B. The

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 01, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Synda

Syndax Pharmaceuticals Reports Third Quarter 2022 Financial Results and Provides Clinical and Business Update – Updated positive data from Phase 1 portion of AUGMENT-101 trial demonstrates CR/CRh rate of 30% and a median durability of response of 9.1

Exhibit 99.1 Syndax Pharmaceuticals Reports Third Quarter 2022 Financial Results and Provides Clinical and Business Update – Updated positive data from Phase 1 portion of AUGMENT-101 trial demonstrates CR/CRh rate of 30% and a median durability of response of 9.1 months – – Enrollment complete in pivotal Phase 2 AGAVE-201 trial of axatilimab in patients with cGVHD - – Company remains on track for

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 03, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Com

Regulation FD Disclosure, Termination of a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 19, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Co

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Pha

Syndax Pharmaceuticals Reports Second Quarter 2022 Financial Results and Provides Clinical and Business Update – On track to report topline data from revumenib and axatilimab pivotal programs starting in 1H23 – – Updated data from Phase 1 portion of

Exhibit 99.1 Syndax Pharmaceuticals Reports Second Quarter 2022 Financial Results and Provides Clinical and Business Update ? On track to report topline data from revumenib and axatilimab pivotal programs starting in 1H23 ? ? Updated data from Phase 1 portion of AUGMENT-101 trial expected in 4Q22 ? ? Company to host conference call today at 4:30 p.m. ET ? WALTHAM, Mass., August 8, 2022 (PRNEWSWIRE

Mutual Release and Settlement Agreement by and between the Company and UCB Biopharma SRL, dated as of June 6, 2022 (incorporated herein by reference to Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q (File No. 001-37708), as filed with the SEC on August 8, 2022).

Exhibit 10.1 Certain identified information marked with [***] has been excluded from the exhibit because it is both not material and is the type that the registrant treats as private or confidential. EXECUTION COPY MUTUAL RELEASE AND SETTLEMENT AGREEMENT This Mutual Release and Settlement Agreement (the ?Settlement Agreement?), effective as of the last date signed below (the ?Settlement Date?), is

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 08, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-37708 32-0162505 (State or Other Jurisdiction of Incorporation) (Commi

Syndax Pharmaceuticals Announces Appointment of Keith A. Goldan as Chief Financial Officer

Exhibit 99.1 Syndax Pharmaceuticals Announces Appointment of Keith A. Goldan as Chief Financial Officer WALTHAM, Mass., June 13, 2022 (PRNEWSWIRE) ? Syndax Pharmaceuticals, Inc. ("Syndax," the "Company" or "we") (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the appointment of Keith A. Goldan to the role of Chief Fi

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): June 8, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commissi

Executive Employment Agreement by and between the Company and Keith A. Goldan, dated as of June 8, 2022 (incorporated herein by reference to Exhibit 10.1 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on June 13, 2022).

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 8th day of June, 2022 (the ?Execution Date?), between KEITH A. GOLDAN (?Executive?) and Syndax Pharmaceuticals, Inc. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A.The Company is a biopharmaceutical company. B.The Compa

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

c UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 11, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commis

Syndax Pharmaceuticals Reports First Quarter 2022 Financial Results and Provides Clinical and Business Update – Topline data from revumenib (SNDX-5613) and axatilimab pivotal programs expected starting in 1H23; Company remains on track for two FDA fi

Exhibit 99.1 Syndax Pharmaceuticals Reports First Quarter 2022 Financial Results and Provides Clinical and Business Update ? Topline data from revumenib (SNDX-5613) and axatilimab pivotal programs expected starting in 1H23; Company remains on track for two FDA filings in 2023 ? ? BEAT-AML and AUGMENT-102 trials assessing revumenib (SNDX-5613) in combination with venetoclax-azacitidine for newly di

Financial Statements and Exhibits, Results of Operations and Financial Condition

c UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 9, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commiss

Executive Employment Agreement by and between the Company and Catherine Madigan, M.D., dated as of March 1, 2022 (incorporated herein by reference to Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q (File No. 001-37708), as filed with the SEC on May 9, 2022).

Exhibit 10.1 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 1st day of March, 2022 (the ?Execution Date?), between CATHERINE MADIGAN, M.D. (?Executive?) and Syndax Pharmaceuticals, Inc. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A.The Company is a biopharmaceutical company. B.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Ph

Executive Employment Agreement by and between the Company and Anjali Ganguli, Ph.D., dated as of September 30, 2021.

Exhibit 10.2 EXECUTIVE EMPLOYMENT AGREEMENT This EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 30th day of September, 2021 (the ?Execution Date?), between ANJALI GANGULI (?Executive?) and Syndax Pharmaceuticals, Inc. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A.The Company is a biopharmaceutical company. B.The

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ? Filed by a party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defini

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.__)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ? Filed by a party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defini

Joint Filing Agreement

Exhibit 99.1.1 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1). Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of them is responsible for the completeness or accur

SNDX / Syndax Pharmaceuticals Inc / Access Industries Holdings LLC - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87164F105 (CUSIP Number) Alejandro Moreno c/o Access Industries, Inc. 40 West 57th St., 28th Floor New York, New York 10019 (212) 247-64

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-37708 Syndax Pharmac

Syndax Pharmaceuticals Reports Fourth Quarter 2021 Financial Results and Provides Clinical and Business Update - Enrollment remains on track for pivotal programs of SNDX-5613 and axatilimab; topline data expected starting in the first half of 2023 -

Exhibit 99.1 Syndax Pharmaceuticals Reports Fourth Quarter 2021 Financial Results and Provides Clinical and Business Update - Enrollment remains on track for pivotal programs of SNDX-5613 and axatilimab; topline data expected starting in the first half of 2023 - - Initiation of three new trials of SNDX-5613 in NPM1 and MLLr acute leukemias, including in the first-line and maintenance settings, exp

Subsidiaries of the Registrant

Exhibit 21.1 SUBSIDIARIES OF SYNDAX PHARMACEUTICALS, INC. NameJurisdiction of Incorporation Syndax Pharmaceuticals, IncDelaware Syndax United KingdomUnited Kingdom Syndax Europe B.V.The Netherlands

Syndax Pharmaceuticals Announces Appointment of Kate Madigan, M.D., as Chief Medical Officer

Exhibit 99.2 Syndax Pharmaceuticals Announces Appointment of Kate Madigan, M.D., as Chief Medical Officer WALTHAM, Mass., March 1, 2022 (PRNEWSWIRE) ? Syndax Pharmaceuticals, Inc. ("Syndax," the "Company" or "we") (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the appointment of Kate Madigan, M.D., to the role of Ch

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Results of Operations and Financial Condition

c UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 1, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commi

Amended and Restated Executive Employment Agreement by and between the Company and Briggs W. Morrison, M.D., dated as of February 2, 2022 (incorporated herein by reference to Exhibit 10.16 to the Company's Annual Report on Form 10-K (File No. 001-37708), as filed with the SEC on March 1, 2022).

Exhibit 10.16 AMENDED & RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 2nd day of February, 2022 (the ?Effective Date?), between Briggs W. Morrison, M.D. (?Executive?) and SYNDAX PHARMACEUTICALS, INC. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A.T

Non-employee Director Compensation Policy, as amended, dated as of February 2, 2022.

Exhibit 10.19 SYNDAX PHARMACEUTICALS, INC. AMENDED & RESTATED NON-EMPLOYEE DIRECTOR COMPENSATION POLICY Effective: February 2, 2022 Each member of the Board of Directors (the ?Board?) who is not also serving as an employee of Syndax Pharmaceuticals, Inc. (the ?Company?) or any of its subsidiaries will receive the compensation described in this Amended and Restated Non-Employee Director Compensatio

First Amendment to the Company’s Loan and Security Agreement with the several banks and financial institutions or entities from time-to-time party thereto and Hercules Capital, Inc., in its capacity as administrative agent for itself and the Lender, dated December 22, 2021.

Exhibit 10.35 FIRST AMENDMENT TO LOAN AND SECURITY AGREEMENT THIS FIRST AMENDMENT TO LOAN AND SECURITY AGREEMENT (this ?Amendment?), dated as of December 22, 2021 (the ?Amendment Effective Date?), is entered into by and among SYNDAX PHARMACEUTICALS, INC., a Delaware corporation, and each of its Qualified Subsidiaries (hereinafter collectively referred to as the ?Borrower?), the several banks and o

Calculation of Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) Syndax Pharmaceuticals, Inc.

Amended and Restated Executive Employment Agreement by and between the Company and Michael A. Metzger, dated as of February 2, 2022 (incorporated herein by reference to Exhibit 10.17 to the

Exhibit 10.17 AMENDED & RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 2nd day of February, 2022 (the ?Effective Date?), between Michael A. Metzger (?Executive?) and SYNDAX PHARMACEUTICALS, INC. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Co

As filed with the Securities and Exchange Commission on March 1, 2022

As filed with the Securities and Exchange Commission on March 1, 2022 Registration No.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 22, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

SNDX / Syndax Pharmaceuticals Inc / Nantahala Capital Management, LLC - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2021 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which

SNDX / Syndax Pharmaceuticals Inc / BIOTECHNOLOGY VALUE FUND L P - AMENDMENT NO. 6 TO THE SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 6)1 Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87164F105 (CUSIP Number) Dece

SNDX / Syndax Pharmaceuticals Inc / Avidity Partners Management LP Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

SNDX / Syndax Pharmaceuticals Inc / ADAGE CAPITAL PARTNERS GP, L.L.C. - SYNDAX PHARMACEUTICALS, INC. Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No.1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2021 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate the rule p

SNDX / Syndax Pharmaceuticals Inc / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 7 )* Syndax Pharmaceuticals Inc (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 2, 2022 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Comm

Amended and Restated Employment Agreement, dated February 2, 2022, by and between the Company and Briggs W. Morrison, M.D.

Exhibit 10.1 AMENDED & RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 2nd day of February, 2022 (the ?Effective Date?), between Briggs W. Morrison, M.D. (?Executive?) and SYNDAX PHARMACEUTICALS, INC. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A.Th

Amended and Restated Employment Agreement, dated February 2, 2022, by and between the Company and Michael A. Metzger.

Exhibit 10.2 AMENDED & RESTATED EXECUTIVE EMPLOYMENT AGREEMENT This AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of the 2nd day of February, 2022 (the ?Effective Date?), between Michael A. Metzger (?Executive?) and SYNDAX PHARMACEUTICALS, INC. (the ?Company?). Certain capitalized terms used in this Agreement are defined in Article 7. RECITALS A. The Com

Syndax Pharmaceuticals Announces Transition of Michael A. Metzger to Chief Executive Officer; Briggs W. Morrison, M.D., to Assume Role of President, Head of Research & Development

Exhibit 99.1 Syndax Pharmaceuticals Announces Transition of Michael A. Metzger to Chief Executive Officer; Briggs W. Morrison, M.D., to Assume Role of President, Head of Research & Development WALTHAM, Mass., February 3, 2022 (PRNEWSWIRE) ? Syndax Pharmaceuticals, Inc. (?Syndax,? the ?Company? or ?we?) (Nasdaq: SNDX), a clinical-stage biopharmaceutical company developing an innovative pipeline of

SNDX / Syndax Pharmaceuticals Inc / Frazier Life Sciences Public Fund, L.P. Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ) Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 20, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 22, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

Form of Pre-Funded Warrant issued pursuant to the securities purchase agreement between the Company and Certain Purchasers, dated December 16, 2021 (incorporated by reference to Exhibit 4.1 to the Company’s Current Report on Form 8-K (File No. 001-37708), as filed with the SEC on December 17, 2021).

Exhibit 4.1 SYNDAX PHARMACEUTICALS, INC. WARRANT TO PURCHASE COMMON STOCK Number of Shares: [ ] (subject to adjustment) Warrant No. [ ] Original Issue Date: , 2021 Syndax Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ]. or its permitted registered assigns (th

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 15, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

Underwriting Agreement, dated December 15, 2021, by and among the Company and Goldman Sachs & Co. LLC.

Exhibit 1.1 3,157,144 Shares SYNDAX PHARMACEUTICALS, INC. COMMON STOCK (PAR VALUE $0.0001 PER SHARE) AND PRE-FUNDED WARRANTS TO PURCHASE 1,142,856 COMMON SHARES UNDERWRITING AGREEMENT December 15, 2021 December 15, 2021 Goldman Sachs & Co. LLC Cowen and Company, LLC c/o Goldman Sachs & Co. LLC 200 West Street New York, New York 10282-2198 c/o Cowen and Company, LLC 599 Lexington Avenue New York, N

CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Amount to be registered Maximum Offering Price Per Share Proposed Maximum Aggregate Offering Price Amount of Registration Fee(1)(4) Common stock, $0.0001 par value per

Table of Contents Filed pursuant to Rule 424(b)(5) Registration No. 333-254661 CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Amount to be registered Maximum Offering Price Per Share Proposed Maximum Aggregate Offering Price Amount of Registration Fee(1)(4) Common stock, $0.0001 par value per share 4,945,000(2) $17.50 $86,537,500 $8,022.03 Pre-funded warrants to

SUBJECT TO COMPLETION, DATED DECEMBER 15, 2021

Table of Contents Filed pursuant to Rule 424(b)(5) Registration No. 333-254661 The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. A registration statement relating to the securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and accompanying prospectus are n

Syndax Pharmaceuticals Announces Updated Positive Data Demonstrating Broad Activity and Tolerability of Axatilimab in Patients with Chronic Graft-Versus-Host Disease – 68% overall response rate and broad multiorgan clinical benefit observed in highly

Exhibit 99.1 Syndax Pharmaceuticals Announces Updated Positive Data Demonstrating Broad Activity and Tolerability of Axatilimab in Patients with Chronic Graft-Versus-Host Disease ? 68% overall response rate and broad multiorgan clinical benefit observed in highly refractory patients treated at doses being assessed in ongoing AGAVE-201 pivotal study ? ? Axatilimab well-tolerated at all doses and sc

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 11, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

Syndax Pharmaceuticals Announces Additional Positive Data Demonstrating Continued Robust Clinical Activity with Durable Responses in Phase 1 Portion of AUGMENT-101 Trial of SNDX-5613 – 55% overall response rate and 24% CR/CRh rate in relapsed/refract

Exhibit 99.2 Syndax Pharmaceuticals Announces Additional Positive Data Demonstrating Continued Robust Clinical Activity with Durable Responses in Phase 1 Portion of AUGMENT-101 Trial of SNDX-5613 ? 55% overall response rate and 24% CR/CRh rate in relapsed/refractory acute leukemia patients with NPM1 or MLLr mutations; no discontinuations due to treatment-related adverse events ? ? CR/CRh rates of

CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Amount to be registered (1) Maximum Offering Price Per Share Maximum Aggregate Offering Price Amount of Registration Fee Common Stock, $0.0001 par value per share 1,42

Table of Contents CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Amount to be registered (1) Maximum Offering Price Per Share Maximum Aggregate Offering Price Amount of Registration Fee Common Stock, $0.

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 9, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Comm

We are dependent upon our collaboration with Incyte to further develop and commercialize axatilimab. If we or Incyte fail to perform as expected or if the collaboration is terminated as a result of actions by the Federal Trade Commission or the Depar

Exhibit 99.1 As used in this Exhibit 99.1, unless the context indicates otherwise, references to ?Syndax,? ?the Company,? ?we,? ?us,? ?our? and similar references refer to Syndax Pharmaceuticals, Inc. and its wholly owned subsidiaries. We are dependent upon our collaboration with Incyte to further develop and commercialize axatilimab. If we or Incyte fail to perform as expected or if the collabora

Purchase Agreement by and between the Company and Incyte Corporation, dated as of September 24, 2021 (incorporated herein by reference to Exhibit 10.2 to the Company’s Quarterly Report on Form 10-Q (File No. 001-37708), as filed with the SEC on November 15, 2021).

Exhibit 10.2 STOCK PURCHASE AGREEMENT THIS STOCK PURCHASE AGREEMENT (this ?Agreement?) is made as of the 24th day of September 2021 (the ?Signing Date?), by and between Syndax Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), and Incyte Corporation, a Delaware corporation (the ?Investor?). WHEREAS, pursuant to the terms and subject to the conditions set forth in this Agreement, the Co

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 15, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Com

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Synda

Syndax Pharmaceuticals Reports Third Quarter 2021 Financial Results and Provides Clinical and Business Update – Initiated pivotal Phase 2 portion of SNDX-5613 AUGMENT-101 trial in patients with NPM1 and MLLr acute leukemias – – Entered global collabo

Exhibit 99.1 Syndax Pharmaceuticals Reports Third Quarter 2021 Financial Results and Provides Clinical and Business Update ? Initiated pivotal Phase 2 portion of SNDX-5613 AUGMENT-101 trial in patients with NPM1 and MLLr acute leukemias ? ? Entered global collaboration with Incyte to develop and commercialize axatilimab for cGVHD and other fibrotic diseases ? ? Updated data from SNDX-5613 and axat

Collaboration and License Agreement by and between the Company and Incyte Corporation, dated as of September 24, 2021 (incorporated herein by reference to Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q (File No. 001-37708), as filed with the SEC on November 15, 2021).

Certain confidential information contained in this document, marked by [***], is omitted because it is not material and is the type of information that the Registrant treats as private or confidential.

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): October 4, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commi

Syndax Pharmaceuticals and Incyte Announce Global Collaboration to Develop and Commercialize Axatilimab for Chronic Graft-Versus-Host Disease and Other Fibrotic Diseases – Syndax to receive $152 million in cash ($117 million upfront plus a $35 millio

Exhibit 99.1 Syndax Pharmaceuticals and Incyte Announce Global Collaboration to Develop and Commercialize Axatilimab for Chronic Graft-Versus-Host Disease and Other Fibrotic Diseases ? Syndax to receive $152 million in cash ($117 million upfront plus a $35 million equity investment), with potential for $450 million in additional milestone payments; 50:50 profit share in the U.S. and double-digit r

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 24, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Co

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 15, 2021 SYNDAX PHARMAC

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 15, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Co

Syndax Appoints Martin H. Huber, M.D, to its Board of Directors

EX-99.1 2 sndx-ex99117.htm EX-99.1 Exhibit 99.1 Syndax Appoints Martin H. Huber, M.D, to its Board of Directors WALTHAM, Mass., September 15, 2021 (PRNEWSWIRE) - Syndax Pharmaceuticals, Inc. ("Syndax," the "Company" or "we") (Nasdaq: SNDX), a clinical stage biopharmaceutical company developing an innovative pipeline of cancer therapies, today announced the expansion of its Board of Directors to ni

As filed with the Securities and Exchange Commission on August 9, 2021

As filed with the Securities and Exchange Commission on August 9, 2021 Registration No.

Syndax Pharmaceuticals Reports Second Quarter 2021 Financial Results and Provides Clinical and Business Update - Intermediate doses selected for Phase 2 portion of AUGMENT-101 trial of SNDX-5613 in patients with genetically-defined acute leukemias; u

Exhibit 99.1 Syndax Pharmaceuticals Reports Second Quarter 2021 Financial Results and Provides Clinical and Business Update - Intermediate doses selected for Phase 2 portion of AUGMENT-101 trial of SNDX-5613 in patients with genetically-defined acute leukemias; updated data from Phase 1 portion expected in 4Q21 ? - Syndax initiating frontline combination of SNDX-5613 with venetoclax and azacitidin

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Pha

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 9, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commis

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 13, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commissi

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37708 Syndax Ph

Syndax Pharmaceuticals Reports First Quarter 2021 Financial Results and Provides Clinical and Business Update - Today announced two of the prior responders from ongoing Phase 1 portion of AUGMENT-101 trial of SNDX-5613 achieved full count recovery br

Exhibit 99.1 Syndax Pharmaceuticals Reports First Quarter 2021 Financial Results and Provides Clinical and Business Update - Today announced two of the prior responders from ongoing Phase 1 portion of AUGMENT-101 trial of SNDX-5613 achieved full count recovery bringing CR/CRh rate up to 23% - - Company on track to initiate pivotal Phase 2 portion of AUGMENT-101 trial in 2Q21 - - Enrollment of 23 c

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 11, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commissi

Syndax Pharmaceuticals Inc.

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) April 28, 2021 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate the rule pursuan

LIMITED POWER OF ATTORNEY

EX-99.2 Exhibit 99.2 LIMITED POWER OF ATTORNEY Know all by these presents, that the undersigned hereby constitutes and appoints Lincoln Benet and Alejandro Moreno, and each of them individually, the undersigned’s true and lawful attorney-in-fact to: • execute for and on behalf of the undersigned, in the undersigned’s capacity as a beneficial owner of Syndax Pharmaceuticals, Inc. (the “Company”), (

Joint Filing Agreement

EX-99.1 Exhibit 99.1 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1). Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of them is responsible for the completeness or

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securiti

Schedule 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. )* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87164F105 (CUSIP Number) Alejandro Moreno c/o Access Industries, Inc. 40 West 57th St., 28th Floor New York, New York 10019 (212) 247

Annual Report - 10-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Amendment No. 1) (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2020 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)*

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

Schedule 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant ? Filed by a party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ? Defini

Form of Debt Securities Warrant Agreement and Warrant Certificate.

Exhibit 4.10 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF DEBT SECURITIES WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF DEBT SECURITIES WARRANT AGREEMENT THIS DEBT SECURITIES WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association]

- S-3ASR

Table of Contents As filed with the Securities and Exchange Commission on March 24, 2021 Registration No.

Form of Preferred Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.9 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF PREFERRED STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF PREFERRED STOCK WARRANT AGREEMENT THIS PREFERRED STOCK WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association] o

Form of Indenture, between the Company and one or more trustees to be named.

EX-4.6 3 d14389dex46.htm EX-4.6 Exhibit 4.6 SYNDAX PHARMACEUTICALS, INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [•], 20 Debt Securities TABLE OF CONTENTS PAGE ARTICLE 1 DEFINITIONS 1 Section 1.01 Definitions of Terms 1 ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 5 Section 2.01 Designation and Terms of Securities 5 Section 2.02 Form of Secur

Sales Agreement dated as of March 22, 2021, between the Registrant and Cowen and Company, LLC.

Exhibit 1.2 SYNDAX PHARMACEUTICALS, INC. Common Stock (par value $0.0001 per share) SALES AGREEMENT March 22, 2021 Cowen and Company, LLC 599 Lexington Avenue New York, NY 10022 Ladies and Gentlemen: Syndax Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), confirms its agreement (this ?Agreement?) with Cowen and Company, LLC (?Cowen?), as follows: 1. Issuance and Sale of Shares. The C

Form of Common Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.8 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF COMMON STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF COMMON STOCK WARRANT AGREEMENT THIS COMMON STOCK WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association] organized

- RW

Syndax Pharmaceuticals, Inc. Building D, Floor 3 35 Gatehouse Drive Waltham, Massachusetts 02451 March 24, 2021 VIA EDGAR Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C 20549 Application for Withdrawal of Registration Statement on Form S-3 (File No. 333-254574) Ladies and Gentlemen: Syndax Pharmaceutics, Inc., a Delaware corporation (the ?Comp

Form of Common Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.8 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF COMMON STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF COMMON STOCK WARRANT AGREEMENT THIS COMMON STOCK WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association] organized

Form of Debt Securities Warrant Agreement and Warrant Certificate.

Exhibit 4.10 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF DEBT SECURITIES WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF DEBT SECURITIES WARRANT AGREEMENT THIS DEBT SECURITIES WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association]

Form of Indenture, between the Company and one or more trustees to be named.

Exhibit 4.6 SYNDAX PHARMACEUTICALS, INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [?], 20 Debt Securities TABLE OF CONTENTS PAGE ARTICLE 1 DEFINITIONS 1 Section 1.01 Definitions of Terms 1 ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 5 Section 2.01 Designation and Terms of Securities 5 Section 2.02 Form of Securities and Trustee?s Certificate

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Table of Contents As filed with the Securities and Exchange Commission on March 22, 2021 Registration No.

Form of Preferred Stock Warrant Agreement and Warrant Certificate.

Exhibit 4.9 SYNDAX PHARMACEUTICALS, INC. AND , AS WARRANT AGENT FORM OF PREFERRED STOCK WARRANT AGREEMENT DATED AS OF SYNDAX PHARMACEUTICALS, INC. FORM OF PREFERRED STOCK WARRANT AGREEMENT THIS PREFERRED STOCK WARRANT AGREEMENT (this ?Agreement?), dated as of [?], between SYNDAX PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and [?], a [corporation] [national banking association] o

Sales Agreement dated as of March 22, 2021, between the Registrant and Cowen and Company, LLC.

Exhibit 1.2 SYNDAX PHARMACEUTICALS, INC. Common Stock (par value $0.0001 per share) SALES AGREEMENT March 22, 2021 Cowen and Company, LLC 599 Lexington Avenue New York, NY 10022 Ladies and Gentlemen: Syndax Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), confirms its agreement (this ?Agreement?) with Cowen and Company, LLC (?Cowen?), as follows: 1. Issuance and Sale of Shares. The C

Form of Deferred Settlement Stock Unit Agreement under 2015 Omnibus Incentive Plan (incorporated herein by reference to Exhibit 10.14 to the Company’s Annual Report on Form 10-K (file No. 001-37708), as filed with the SEC on March 12, 2021).

EXHIBIT 10.14 SYNDAX PHARMACEUTICALS, INC. 2015 OMNIBUS INCENTIVE PLAN STOCK UNIT AGREEMENT ? DEFERRED SETTLEMENT Syndax Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), hereby grants Stock Units denominated in shares of its common stock, par value $0.0001 per share (this ?Award?), to the Grantee named below, subject to the vesting and other conditions set forth below. Additional ter

Annual Report - 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2020 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Commission File Number: 001-37708 Syndax Pharmac

Syndax Pharmaceuticals Reports Fourth Quarter 2020 Financial Results and Provides Clinical and Business Update - Phase 1 AUGMENT-101 data expected in late 1Q21 or early 2Q21; Phase 2 expansion cohorts expected to commence in 2Q21 - - Enrollment under

Exhibit 99.1 Syndax Pharmaceuticals Reports Fourth Quarter 2020 Financial Results and Provides Clinical and Business Update - Phase 1 AUGMENT-101 data expected in late 1Q21 or early 2Q21; Phase 2 expansion cohorts expected to commence in 2Q21 - - Enrollment underway in pivotal Phase 2 AGAVE-201 trial of axatilimab in cGVHD - - End of year cash balance of $293.1 million provides cash runway into 20

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 8, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Commiss

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 (Title of Class of Securit

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2020 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)*

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendm

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 5)1 Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87164F105 (CUSIP Number) Dece

JOINT FILING AGREEMENT

EX-99.A EXHIBIT A JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Syndax Pharmaceuticals, Inc. and further agree that this agreement be included as an exhibit to such fili

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 3)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) (CUSIP Number)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 3)* Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2020 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate the rule pursuant to which

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 3, 2021 SYNDAX PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-37708 32-0162505 (state or other jurisdiction of incorporation) (Comm

SCHEDULE 13G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 6 )* Syndax Pharmaceuticals Inc (Name of Issuer) Common Stock (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2020 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which

SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2) * Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securiti

SC 13G/A SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2) * Syndax Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87164F105 (CUSIP Number) December 31, 2020 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate