SNDX Syndax Pharmaceuticals Inc

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES                                                                                   
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940                       

1. Name and Address of Reporting Person * Egros Fabrice	2. Issuer Name and Ticker or Trading Symbol Syndax Pharmaceuticals Inc [ SNDX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director                    _____ 10% Owner _____ Officer (give title below)    _____ Other (specify below)
(Last)          (First)          (Middle) C/O SYNDAX PHARMACEUTICALS, INC., 35 GATEHOUSE DRIVE, BUILDING D, FLOOR 3	3. Date of Earliest Transaction (MM/DD/YYYY) 5/18/2021
(Street) WALTHAM, MA 02451 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	5/18/2021		M		11926.00	A	$7.20	27926.00	D
Common Stock	5/18/2021		M		1683.00	A	$7.88	29609.00	D
Common Stock	5/18/2021		S(1)		11926.00	D	$18.6482	17683.00	D
Common Stock	5/18/2021		S(1)		1683.00	D	$18.6482	16000.00	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (Right to buy)	$7.88	5/18/2021		M			1683.00	(2)	6/10/2029	Common Stock	0.00	$0.00	0.00	D
Stock Options (Right to buy)	$7.20	5/18/2021		M			11926.00	(2)	8/18/2025	Common Stock	0.00	$0.00	0.00	D

Explanation of Responses:
(1)	The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 plan adopted by the Reporting Person. Following the sale reported in this Form 4, the Reporting Person has a total of 93,317 options to purchase shares of common stock that are vested and immediately exercisable and a total of 0 options to purchase shares of common stock that have not yet vested.
(2)	This option is fully vested.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Egros Fabrice C/O SYNDAX PHARMACEUTICALS, INC. 35 GATEHOUSE DRIVE, BUILDING D, FLOOR 3 WALTHAM, MA 02451	X

Signatures
/s/ Michael A. Metzger, Attorney-in-Fact		5/20/2021
**Signature of Reporting Person		Date