SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP 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: 3235-0287 Estimated average burden hours per response: 0.5
X	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* BVF PARTNERS L P/IL (Last) (First) (Middle) 227 WEST MONROE STREET, SUITE 4800 (Street) CHICAGO IL 60606 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ARENA PHARMACEUTICALS INC [ ARNA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) X Other (specify below) Indirect Beneficial Owner
	3. Date of Earliest Transaction (Month/Day/Year) 07/07/2004
	4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction 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	07/07/2004		S		232,500	D	$5.1	584,977(3)	I	See footnotes(1)(2)
Common Stock	07/07/2004		S		147,000	D	$5.1	379,884(4)	I	See footnotes(1)(2)
Common Stock	07/07/2004		S		356,500	D	$5.1	1,038,851(5)	I	See footnotes(1)(2)
Common Stock	07/07/2004		S		8,288	D	$5.2031	576,689(3)	I	See footnotes(1)(2)
Common Stock	07/07/2004		S		5,000	D	$5.2031	374,884(4)	I	See footnotes(1)(2)
Common Stock	07/07/2004		S		12,000	D	$5.2031	1,026,851(5)	I	See footnotes(1)(2)
Common Stock	07/08/2004		S		21,800	D	$5	554,889(3)	I	See footnotes(1)(2)
Common Stock	07/08/2004		S		13,000	D	$5	361,884(4)	I	See footnotes(1)(2)
Common Stock	07/08/2004		S		32,000	D	$5	994,851(5)	I	See footnotes(1)(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction 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 (Month/Day/Year)		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: 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

1. Name and Address of Reporting Person* BVF PARTNERS L P/IL (Last) (First) (Middle) 227 WEST MONROE STREET, SUITE 4800 (Street) CHICAGO IL 60606 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) X Other (specify below) Indirect Beneficial Owner

1. Name and Address of Reporting Person* BIOTECHNOLOGY VALUE FUND L P (Last) (First) (Middle) 227 W MONROE STREET, SUITE 4800 (Street) CHICAGO IL 60606 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) Direct Beneficial Owner

1. Name and Address of Reporting Person* BIOTECHNOLOGY VALUE FUND II LP (Last) (First) (Middle) 227 WEST MONROE STREET, SUITE 4800 (Street) CHICAGO IL 60606 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) Direct Beneficial Owner

1. Name and Address of Reporting Person* BVF INVESTMENTS LLC (Last) (First) (Middle) 227 WEST MONROE STREET, SUITE 4800 (Street) CHICAGO IL 60606 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director 10% Owner Officer (give title below) X Other (specify below) Direct Beneficial Owner

1. Name and Address of Reporting Person* BVF INC/IL (Last) (First) (Middle) ONE SANSOME STREET, 31ST FLOOR (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) X Other (specify below) Indirect Beneficial Owner

Explanation of Responses:

1. The shares reported in this response are beneficially owned by Biotechnology Value Fund, L.P., a Delaware limited partnership ("BVF, L.P.") (554,889 shares ); Biotechnology Value Fund II, L.P., a Delaware limited partnership ("BVF2, L.P.") (361,884 shares); BVF Investments, L.L.C., a Delaware limited liability company ("Investments") (994,851 shares); and by BVF Partners L.P., a Delaware limited partnership ("Partners"), and by its general partner BVF Inc., a Delaware corporation ("BVF Inc."), which is also an investment advisor to Partners. Partners is the general partner of BVF, L.P. and BVF2, L.P. and is the manager of Investments. Pursuant to the operating agreement of Investment Partners is authorized, among other things, to invest the funds of Ziff Asset Management, L.P., the majority member of Investments, in the shares of common stock described herein as being beneficially owned by Investments.

2. Mark N. Lampert is the sole shareholder and sole director of BVF Inc., and is an officer of BVF Inc. This joint filing on Form 4 shall not be deemed an admission that Mark N. Lampert is, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise, the beneficial owner of any equity securities covered by this joint filing. Mr. Lampert disclaims beneficial ownership of shares reported in this response, except to the extent that he has a pecuniary interest therein.

3. Shares beneficailly owned by BVF, L.P.

4. Shares beneficailly owned by BVF2, L.P.

5. Shares beneficailly owned by Investments

	By: /s/ BVF Partners L.P., By: BVF Inc., its GP, By: /s/ Mark N. Lampert	07/09/2004
	By: /s/ BIOTECHNOLOGY VALUE FUND, L.P. By BVF Partners L.P., its GP, By: BVF Inc., By: /s/ Mark N. Lampert	07/09/2004
	By: /s/ BIOTECHNOLOGY VALUE FUND II, L.P. By BVF Partners L.P., its GP, By: BVF Inc., By: /s/ Mark N. Lampert	07/09/2004
	By: /s/ BVF INVESTMENTS, L.L.C, By: BVF Partners L.P., its Manager, By: BVF Inc., By: /s/ Mark N. Lampert	07/09/2004
	By: /s/ BVF INC., By: /s/ Mark N. Lampert	07/09/2004
	** 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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