- Statement of Changes in Beneficial Ownership (4)

FORM 4 [ X ] 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	OMB APPROVAL OMB Number: 3235-0287 Expires: February 28, 2011 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* WARBURG PINCUS PRIVATE EQUITY VIII L P	2. Issuer Name and Ticker or Trading Symbol NEUROGEN CORP [ NRGN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) __ X __ Other (specify below) See Remarks
(Last) (First) (Middle) C/O WARBURG PINCUS LLC, 450 LEXINGTON AVENUE	3. Date of Earliest Transaction (MM/DD/YYYY) 12/23/2009
(Street) NEW YORK, NY 10017 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock, par value $0.025 per share ⁽¹⁾	12/23/2009		J ⁽¹⁾ ⁽²⁾		13571411	D	⁽²⁾	0	D ⁽¹⁾

*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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)
Warrant to Purchase Common Stock ⁽¹⁾ ⁽³⁾	⁽³⁾							⁽³⁾	⁽³⁾	Common Stock	2499991 ⁽³⁾		1	I ⁽¹⁾ ⁽³⁾	See Footnotes ⁽¹⁾ ⁽³⁾

Explanation of Responses:
( 1)	See Exhibit 99.1 - Explanation of Responses.
( 2)	See Exhibit 99.1 - Explanation of Responses.
( 3)	See Exhibit 99.1 - Explanation of Responses.

Remarks:
(1) Exhibit 99.1 - Explanation of Responses
(2) Exhibit 99.2 - Joint Filers' Names and Addresses
(3) Exhibit 99.3 - Joint Filers' Signatures

On December 23, 2009, Neon Signal, LLC, a Delaware limited liability company ("Merger Sub") and a wholly owned subsidiary of
Ligand Pharmaceuticals Incorporated, a Delaware corporation ("Ligand"), was merged (the "Merger") with and into Neurogen
Corporation, a Delaware corporation ("Neurogen"), pursuant to an Agreement and Plan of Merger, dated as of August 23, 2009
(the "Merger Agreement"), by and among Merger Sub, Ligand and Neurogen. In connection with the Merger, the shares of the
common stock of Neurogen, par value $0.025 per share, owned by Warburg Pincus Private Equity VIII, L.P., a Delaware limited
partnership, were cancelled in exchange for the merger consideration provided in the Merger Agreement.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
WARBURG PINCUS PRIVATE EQUITY VIII L P C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK, NY 10017				See Remarks
Warburg Pincus Partners LLC C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK, NY 10017				See Remarks
WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK, NY 10017				See Remarks
WARBURG PINCUS & CO C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK, NY 10017				See Remarks
KAYE CHARLES R C/O WARBURG PINCUS LLC 450 LEXINGTON AVE NEW YORK, NY 10017				See Remarks
LANDY JOSEPH C/O WARBURG PINCUS LLC 450 LEXINGTON AVE NEW YORK, NY 10017				See Remarks

Signatures
WARBURG PINCUS PRIVATE EQUITY VIII, L.P. By: Warburg Pincus Partners, LLC, its General Partner By: Warburg Pincus & Co., its Managing Member By: /s/ Scott A. Arenare, Partner		12/23/2009
^** 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 4(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).
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