SECURITIES AND EXCHANGE COMMISSION
Washington, DC 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 13d-2(b)
(Amendment No. 2)

Neurogen Corporation (Name of Issuer)

Common Stock (Title of Class of Securities)

64124E 10 6 (CUSIP Number)

February 14, 2004 (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o Rule 13d-1(b)
ý Rule 13d-1(c)
o Rule 13d-1(d)

CUSIP No. 64124E 10 6 13G Page 2 of 10 Pages

1	NAME OF REPORTING PERSON: Biotechnology Value Fund, L.P. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

	5	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		738,825
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		738,825

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	738,825
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	4.11%
12	TYPE OF REPORTING PERSON*
	PN

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No.64124E 10 6 13G Page 3 of 10 Pages

1	NAME OF REPORTING PERSON: Biotechnology Value Fund II, L.P. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

	7	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		454,736
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		454,736

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	454,736
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	2.53%
12	TYPE OF REPORTING PERSON*
	PN

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 64124E 10 6 13G Page 4 of 10 Pages

1	NAME OF REPORTING PERSON: BVF Investments, L.L.C. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

	5	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		1,200,102
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		1,200,102

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	1,200,102
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	6.68%
12	TYPE OF REPORTING PERSON*
	OO

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 64124E 10 6 13G Page 5 of 10 Pages

1	NAME OF REPORTING PERSON: Investment 10, L.L.C. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Illinois

	5	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		138,186
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		138,186

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	138,186
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	0.77%
12	TYPE OF REPORTING PERSON*
	OO

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 64124E 10 6 13G Page 6 of 10 Pages

1	NAME OF REPORTING PERSON: BVF Partners L.P. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

	5	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		2,531,849
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		2,531,849

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	2,531,849
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
	14.09%
12	TYPE OF REPORTING PERSON*
	PN

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 64124E 10 6 13G Page 7 of 10 Pages

1	NAME OF REPORTING PERSON: BVF Inc. I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY):
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*	(a)  ý
		(b)  o
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

	5	SOLE VOTING POWER
NUMBER OF		0
SHARES
BENEFICIALLY	6	SHARED VOTING POWER
OWNED		2,531,849
BY
EACH	7	SOLE DISPOSITIVE POWER
REPORTING		0
PERSON
WITH:	8	SHARED DISPOSITIVE POWER
		2,531,849

9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	2,531,849
10	CHECK IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*	o
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
	14.09%
12	TYPE OF REPORTING PERSON*
	CO

*SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 64124E 10 6 13G Page 8 of 10 Pages

ITEM 1(a).	NAME OF ISSUER: Neurogen Corporation ("Neurogen")
ITEM 1(b).	ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES: 35 Northeast Industrial Road Branford, CT 06405
ITEM 2(a).	NAME OF PERSON FILING:
This Amendment to Schedule 13G is being filed on behalf of the following persons (the "Reporting Persons"):
	(i)	Biotechnology Value Fund, L.P. ("BVF")
	(ii)	Biotechnology Value Fund II, L.P. ("BVF2")
	(iii)	BVF Investments, L.L.C. ("Investments")
	(iv)	Investment 10, L.L.C. ("ILL10")
	(v)	BVF Partners L.P. ("Partners")
	(vi)	BVF Inc. ("BVF Inc.")
ITEM 2(b).	ADDRESS OF PRINCIPAL BUSINESS OFFICE:
The principal business office of the persons comprising the group filing this Amendment to Schedule 13G is located at 227 West Monroe Street, Suite 4800, Chicago, Illinois, 60606.
ITEM 2(c).	CITIZENSHIP:

BVF:	a Delaware limited partnership
BVF2:	a Delaware limited partnership
Investments:	a Delaware limited liability company
ILL10:	an Illinois limited liability company
Partners:	a Delaware limited partnership
BVF Inc.:	a Delaware corporation

ITEM 2(d).	TITLE OF CLASS OF SECURITIES:
This Amendment to Schedule 13G is being filed with respect to the common stock, par value $0.025 per share (the "Common Stock"), of Neurogen. The Reporting Persons' percentage ownership of the Common Stock is based on 17,965,147 shares of the Common Stock being outstanding.
ITEM 2(e).	CUSIP Number:

CUSIP No. 64124E 10 6 13G Page 9 of 10 Pages

ITEM 3.	IF THIS STATEMENT IS FILED PURSUANT TO RULE 13d-1(b), or 13d-2(b) or (c) CHECK WHETHER THE PERSON FILING IS: One of the following
	Not applicable as this Amendment to Schedule 13G is filed pursuant to Rule 13d-1(c).
ITEM 4.	OWNERSHIP:
	The information in items 1 and 5 through 11 on the cover pages (pp. 2 - 8) on this Amendment to Schedule 13G is hereby incorporated by reference.
ITEM 5.	OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS:
	If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities check the following. o
ITEM 6.	OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON:
	Pursuant to the operating agreement of Investments, Partners is authorized, among other things, to invest the funds of Ziff Asset Management, L.P., the majority member of Investments, in shares of the Common Stock and to vote and exercise dispositive power over those shares of the Common Stock. Partners and BVF Inc. share voting and dispositive power over shares of the Common Stock beneficially owned by BVF, BVF2, Investments and those owned by ILL10, on whose behalf Partners acts as an investment manager and, accordingly, Partners and BVF Inc. have beneficial ownership of all of the shares of the Common Stock owned by such parties.
ITEM 7.	IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY:
	Not applicable.
ITEM 8.	IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF A GROUP:
	Not applicable.
ITEM 9.	NOTICE OF DISSOLUTION OF GROUP:
	Not applicable.

CUSIP No. 64124E 10 6 13G Page 10 of 10 Pages

ITEM 10. CERTIFICATION

        By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

        After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated:	February 10, 2004
	BIOTECHNOLOGY VALUE FUND, L.P.
	By:	BVF Partners L.P., its general partner
		By:	BVF Inc., its general partner
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President
	BIOTECHNOLOGY VALUE FUND II, L.P.
	By:	BVF Partners L.P., its general partner
		By:	BVF Inc., its general partner
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President
	BVF INVESTMENTS, L.L.C.
	By:	BVF Partners L.P., its manager
		By:	BVF Inc., its general partner
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President
	INVESTMENT 10, L.L.C.
	By:	BVF Partners L.P., its attorney-in-fact
		By:	BVF Inc., its general partner
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President
	BVF PARTNERS L.P.
	By:	BVF Inc., its general partner
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President
	BVF INC.
			By:	/s/  MARK N. LAMPERT
				Mark N. Lampert President