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. )1
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Syndax Pharmaceuticals, Inc.
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(Name of Issuer)
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Common Stock, $0.0001 par value
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(Title of Class of Securities)
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87164F105
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(CUSIP Number)
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December 31, 2016
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Date of Event Which Requires Filing of this Statement
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Check the appropriate box to designate the rule pursuant to which this Schedule is Filed:
[ ] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[X] Rule 13d-1(d)
_______________________
1The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.
CUSIP No. 87164F105
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1)
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Name of Reporting Person
I.R.S. Identification No. of Above Person (Entities Only) (Voluntary)
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Domain Partners VIII, L.P.
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2)
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Check the Appropriate Box if a Member of a Group
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(a) [X]
(b) [ ]
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3)
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SEC Use Only
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4)
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Citizenship or Place of Organization
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Delaware
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Number of
Shares Beneficially
Owned by Each
Reporting Person
With
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5)
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Sole Voting Power
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761,062 shares of Common Stock *
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6)
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Shared Voting Power
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-0-
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7)
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Sole Dispositive Power
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761,062 shares of Common Stock *
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8)
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Shared Dispositive Power
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-0-
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9)
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Aggregate Amount Beneficially Owned by Each Reporting Person
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761,062 shares of Common Stock *
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10)
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Check if the Aggregate Amount in Row (9) Excludes Certain Shares
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[ ]
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11)
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Percent of Class Represented by Amount in Row (9)
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4.2% **
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12)
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Type of Reporting Person
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PN
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* As of December 31, 2016
** Based on 18,223,723 shares of Common Stock outstanding as of December 31, 2016, as provided to the Reporting Persons by the Issuer.
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CUSIP No. 87164F105
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1)
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Name of Reporting Person
I.R.S. Identification No. of Above Person (Entities Only) (Voluntary)
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DP VIII Associates, L.P.
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2)
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Check the Appropriate Box if a Member of a Group
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(a) [X]
(b) [ ]
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3)
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SEC Use Only
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4)
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Citizenship or Place of Organization
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Delaware
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Number of
Shares Beneficially
Owned by Each
Reporting Person
With
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5)
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Sole Voting Power
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5,641 shares of Common Stock *
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6)
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Shared Voting Power
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-0-
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7)
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Sole Dispositive Power
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5,641 shares of Common Stock *
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8)
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Shared Dispositive Power
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-0-
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9)
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Aggregate Amount Beneficially Owned by Each Reporting Person
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5,641 shares of Common Stock *
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10)
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Check if the Aggregate Amount in Row (9) Excludes Certain Shares
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[ ]
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11)
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Percent of Class Represented by Amount in Row (9)
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Less than 0.1% **
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12)
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Type of Reporting Person
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PN
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* As of December 31, 2016
** Based on 18,223,723 shares of Common Stock outstanding as of December 31, 2016, as provided to the Reporting Persons by the Issuer.
3
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1)
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Name of Reporting Person
I.R.S. Identification No. of Above Person (Entities Only) (Voluntary)
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Domain Partners VI, L.P.
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2)
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Check the Appropriate Box if a Member of a Group
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(a) [X]
(b) [ ]
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3)
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SEC Use Only
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4)
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Citizenship or Place of Organization
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Delaware
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Number of
Shares Beneficially
Owned by Each
Reporting Person
With
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5)
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Sole Voting Power
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1,743,854 shares of Common Stock *
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6)
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Shared Voting Power
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-0-
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7)
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Sole Dispositive Power
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1,743,854 shares of Common Stock *
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8)
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Shared Dispositive Power
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-0-
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9)
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Aggregate Amount Beneficially Owned by Each Reporting Person
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1,743,854 shares of Common Stock *
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10)
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Check if the Aggregate Amount in Row (9) Excludes Certain Shares
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[ ]
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11)
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Percent of Class Represented by Amount in Row (9)
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9.6% **
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12)
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Type of Reporting Person
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PN
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* As of December 31, 2016
** Based on 18,223,723 shares of Common Stock outstanding as of December 31, 2016, as provided to the Reporting Persons by the Issuer.
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CUSIP No. 87164F105
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1)
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Name of Reporting Person
I.R.S. Identification No. of Above Person (Entities Only) (Voluntary)
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DP VI Associates, L.P.
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2)
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Check the Appropriate Box if a Member of a Group
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(a) [X]
(b ) [ ]
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3)
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SEC Use Only
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4)
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Citizenship or Place of Organization
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Delaware
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Number of
Shares Beneficially
Owned by Each
Reporting Person
With
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5)
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Sole Voting Power
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13,925 shares of Common Stock *
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6)
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Shared Voting power
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-0-
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7)
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Sole Dispositive Power
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13,925 shares of Common Stock *
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8)
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Shared Dispositive Power
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-0-
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9)
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Aggregate Amount Beneficially Owned by Each Reporting Person
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13,925 shares of Common Stock *
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10)
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Check if the Aggregate Amount in Row (9) Excludes Certain Shares
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[ ]
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11)
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Percent of Class Represented by Amount in Row (9)
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0.1% **
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12)
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Type of Reporting Person
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PN
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* As of December 31, 2016
** Based on 18,223,723 shares of Common Stock outstanding as of December 31, 2016, as provided to the Reporting Persons by the Issuer.
5
CUSIP No. 87164F105
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1)
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Name of Reporting Person
I.R.S. Identification No. of Above Person (Entities Only) (Voluntary)
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Domain Associates, LLC
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2)
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Check the Appropriate Box if a Member of a Group
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(a) [X]
(b) [ ]
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3)
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SEC Use Only
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4)
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Citizenship or Place of Organization
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Delaware
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Number of
Shares Beneficially
Owned by Each
Reporting Person
With
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5)
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Sole Voting Power
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13,564 shares of Common Stock *
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6)
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Shared Voting Power
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-0-
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7)
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Sole Dispositive Power
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13,564 shares of Common Stock *
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8)
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Shared Dispositive Power
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-0-
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9)
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Aggregate Amount Beneficially Owned by Each Reporting Person
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13,564 shares of Common Stock *
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10)
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Check if the Aggregate Amount in Row (9) Excludes Certain Shares
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11)
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Percent of Class Represented by Amount in Row (9)
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0.1% **
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12)
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Type of Reporting Person
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PN
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* As of December 31, 2016
** Based on 18,223,723 shares of Common Stock outstanding as of December 31, 2016, as provided to the Reporting Persons by the Issuer.
6
CUSIP No. 87164F105
Schedule 13G
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Item 1(a)
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–
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Name of Issuer:
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Syndax Pharmaceuticals, Inc.
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Item 1(b)
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–
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Address of Issuer's Principal Executive Offices:
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400 Totten Pond Road, Suite 110, Waltham, MA 02451
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Item 2(a)
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Name of Person Filing:
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This statement is being filed by Domain Partners VIII, L.P., a Delaware limited partnership ("Domain VIII"), DP VIII Associates, L.P., a Delaware limited partnership ("DP VIII A"), Domain Partners VI, L.P., a Delaware limited partnership ("Domain VI"), DP VI Associates, L.P., a Delaware limited partnership ("DP IV A"), and Domain Associates, LLC ("DA") (together, the "Reporting Persons").
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Item 2(b)
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Address of Principal Business Office:
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One Palmer Square, Princeton, NJ 08542
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Item 2(c)
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Place of Organization:
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Domain VIII: Delaware
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DP VIII A: Delaware
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Domain VI: Delaware
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DP VI A: Delaware
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DA: Delaware
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Item 2(d)
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–
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Title of Class of Securities:
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Common Stock, $0.0001 par value
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Item 2(e)
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–
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CUSIP Number:
87164F105
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Item 3
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–
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Statements Filed Pursuant to Rules 13d-1(b) or 13d-2(b):
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Not applicable.
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CUSIP No. 87164F105
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Item 4
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–
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Ownership.
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(a) through (c):
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The information set forth in Items 5 through 9 and 11 of the cover pages to this Schedule 13G is incorporated herein by reference.
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Item 5
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–
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Ownership of Five Percent or Less of a Class:
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Not applicable.
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Item 6
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Ownership of More than Five Percent on Behalf of Another Person:
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Not applicable.
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Item 7
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–
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Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Company:
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Not applicable.
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Item 8
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–
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Identification and Classification of Members of the Group:
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See Exhibit 2.
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Item 9
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–
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Notice of Dissolution of Group:
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Not applicable.
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Item 10
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–
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Certification:
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Not applicable.
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8
CUSIP No. 87164F105
Signature
After reasonable inquiry and to the best of their knowledge and belief, the undersigned hereby certify that the information set forth in this statement is true, complete and correct.
Dated: January 9, 2017
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DOMAIN PARTNERS VIII, L.P.
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By:
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One Palmer Square Associates VIII, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DP VIII ASSOCIATES, L.P.
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By:
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One Palmer Square Associates VIII, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DOMAIN PARTNERS VI, L.P.
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By:
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One Palmer Square Associates VI, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DP VI ASSOCIATES, L.P.
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By:
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One Palmer Square Associates VI, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DOMAIN ASSOCIATES, LLC
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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9
CUSIP No. 87164F105
Exhibit 1
Joint Filing Agreement
The undersigned hereby agree that the statement on Schedule 13G to which this Agreement is annexed as Exhibit 1, and any amendments thereto, is and will be filed on behalf of each of them in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended.
Dated: January 9, 2017
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DOMAIN PARTNERS VIII, L.P.
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By:
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One Palmer Square Associates VIII, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DP VIII ASSOCIATES, L.P.
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By:
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One Palmer Square Associates VIII, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DOMAIN PARTNERS VI, L.P.
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By:
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One Palmer Square Associates VI, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DP VI ASSOCIATES, L.P.
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By:
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One Palmer Square Associates VI, L.L.C., General Partner
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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DOMAIN ASSOCIATES, LLC
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By:
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/s/ Lisa A. Kraeutler
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Attorney-in-Fact
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10
CUSIP No. 87164F105
Exhibit 2
Identification and Classification of Members of the Group
Domain Partners VIII, L.P., DP VIII Associates, L.P., Domain Partners VI, L.P., DP VI Associates, L.P. and Domain Associates, LLC are filing this statement on Schedule 13G as a group.
Domain Partners VIII, L.P. is a Delaware limited partnership. Its sole general partner is One Palmer Square Associates VIII, L.L.C., a Delaware limited liability company.
DP VIII Associates, L.P. is a Delaware limited partnership. Its sole general partner is One Palmer Square Associates VIII, L.L.C., a Delaware limited liability company.
Domain Partners VI, L.P. is a Delaware limited partnership. Its sole general partner is One Palmer Square Associates VI, L.L.C., a Delaware limited liability company.
DP VI Associates, L.P. is a Delaware limited partnership. Its sole general partner is One Palmer Square Associates VI, L.L.C., a Delaware limited liability company.
Domain Associates, LLC is a Delaware limited liability company.
11