SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0104 Estimated average burden hours per response: 0.5

1. Name and Address of Reporting Person* DP VI Associates, L.P. (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 03/02/2016	3. Issuer Name and Ticker or Trading Symbol Syndax Pharmaceuticals Inc [ SNDX ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A-1 Preferred Stock	(1)	(1)	Common Stock	13,925	(1)	D(2)(3)(4)(5)(6)

1. Name and Address of Reporting Person* DP VI Associates, L.P. (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* BLAIR JAMES C (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* DOVEY BRIAN H (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TREU JESSE I (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* VITULLO NICOLE (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE (Street) PRINCETON NJ 08542 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. All outstanding Preferred Stock will automatically convert into Common Stock on a one-for-one basis immediately prior to the closing of the Issuer's initial public offering for no additional consideration. The Preferred Stock has no expiration date.

2. The securities reported as directly beneficially owned by the designated Reporting Person may be deemed to be indirectly beneficially owned by each of the Reporting Owners listed below, each of whom is a managing member of One Palmer Square Associates VI, LLC, the sole general partner of the designated Reporting Person. Pursuant to Instruction 5(b)(iv) of Form 3, each such individual has elected to report as indirectly beneficially owned the entire number of securities owned by the designated Reporting Person, however each of them disclaims beneficial ownership of any securities, and any proceeds thereof, that exceed his or her pecuniary interest therein and/or that are not actually distributed to him or her.

3. As managing members of the sole general partner of DP VIII Associates, L.P., each Reporting Owner listed below may also be deemed to indirectly beneficially own the securities of the Issuer held by DP VIII Associates, L.P., as reported on a Form 3 for DP VIII Associates, L.P. filed on the same date as this Form 3.

4. As managing members of the sole general partner of Domain Partners VI, L.P., each Reporting Owner listed below may also be deemed to indirectly beneficially own the securities of the Issuer held by Domain Partners VI, L.P., as reported on a Form 3 for Domain Partners VI, L.P. filed on the same date as this Form 3.

5. As managing members of the sole general partner of Domain Partners VIII, L.P. each Reporting Owner listed below may also be deemed to indirectly beneficially own the securities of the Issuer held by Domain Partners VIII, L.P. as reported on a Form 3 for Domain Partners VIII, L.P. filed on the same date as this Form 3.

6. As managing members of Domain Associates, LLC, each Reporting Owner listed below may also be deemed to indirectly beneficially own the securities of the Issuer held by Domain Associates, LLC, as reported on a Form 3 for Domain Associates, LLC filed on the same date as this Form 3.

Remarks:

	/s/ Lisa A. Kraeutler, as Attorney-in Fact for DP VI Associates, L.P., J. Blair, B. Dovey, J. Treu and N. Vitullo	03/02/2016
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.