Michael A. Metzger - 04 Feb 2026 Form 4 Insider Report for Syndax Pharmaceuticals Inc (SNDX)

Role: Chief Executive Officer, Director
Signature: /s/ Michael A. Metzger
Issuer symbol: SNDX
Transactions as of: 04 Feb 2026
Net transactions value: +$8,836,365
Form type: 4
Filing time: 06 Feb 2026, 17:54:06 UTC
Previous filing: 08 Sep 2025
Next filing: 10 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Metzger Michael A	Chief Executive Officer, Director	C/O SYNDAX PHARMACEUTICALS, INC., 730 3RD AVENUE, FLOOR 9, NEW YORK	/s/ Michael A. Metzger	06 Feb 2026	0001507220

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SNDX	Common Stock	Award	$0	+73,000	+24%	$0.000000	371,661	04 Feb 2026	Direct	F1
transaction	SNDX	Common Stock	Award	$0	+144,600	+39%	$0.000000	516,261	04 Feb 2026	Direct	F2
transaction	SNDX	Common Stock	Sale	$152,835	-7,412	-1.4%	$20.62	508,849	06 Feb 2026	Direct	F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	SNDX	Stock Options (Right to buy)	Award	$8,989,200	+440,000		$20.43	440,000	04 Feb 2026	Common Stock	440,000	$20.43	Direct	F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Award of restricted stock units ("RSUs"), representing the right to receive one share of Common Stock for each RSU. One third (1/3rd) of the shares of Common Stock subject to such RSU shall vest annually on the anniversary of the Vesting Commencement Date, during the Reporting Person's continued service as an employee, consultant, director or officer of the Company over the three (3) years following the date of grant, until all of the shares subject to such RSU are fully vested.
F2	Award of RSUs, representing the right to receive one share of Common Stock for each RSU. The number of shares of Common Stock acquired upon vesting of the RSUs is contingent upon the achievement of pre-established performance metrics, as approved by the Company's Compensation Committee, subject to the Reporting Person's continued service as an employee, consultant, director or officer of the Company.
F3	Represents the number of shares required to be sold by the reporting person to cover tax withholding obligations in connection with the vesting of restricted stock units.
F4	1/48th of the shares subject to the option shall vest monthly over a four-year period.