FORM 4 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 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(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Flynn James E   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) _____ Other (specify below) (Last) (First) (Middle) 780 THIRD AVENUE, 37TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 10/19/2007 (Street) NEW YORK, NY 10017 4. If Amendment, Date 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 (City) (State) (Zip) 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 (1) 10/19/2007   S   9,125 D $ 10.5074 1,861,735 I Through Deerfield Partners, L.P (2) Common Stock (1) 10/19/2007   S   15,875 D $ 10.5074 3,238,908 I Through Deerfield International Limited (3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities (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)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Flynn James E 780 THIRD AVENUE 37TH FLOOR NEW YORK, NY 10017		X
DEERFIELD CAPITAL LP 780 THIRD AVENUE 37TH FLOOR NEW YORK, NY 10017		X
DEERFIELD MANAGEMENT CO /NY 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY 10017		X
DEERFIELD INTERNATIONAL LTD		X
DEERFIELD PARTNERS, LP 780 THIRD AVENUE 37TH FLOOR NEW YORK, NY 10017		X

Signatures

/s/ Darren Levine		10/23/2007
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	This Form 4 is being filed by James E. Flynn and by the entities listed on the Joint Filer Information Statement attached hereto (the "Reporting Persons").
(2)	Deerfield Capital, L.P. is the general partner of Deerfield Partners, L.P. (the "Domestic Fund"). James E. Flynn is the managing member of the general partner of Deerfield Capital, L.P. In accordance with Instruction 4(b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Domestic Fund is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.
(3)	Deerfield Management Company, L.P. is the investment manager of Deerfield International Limited (the "Offshore Fund"). James E. Flynn is the managing member of the general partner of Deerfield Management Company, L.P. In accordance with Instruction 4(b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Offshore Fund is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.
Remarks: Darren Levine, Attorney-In-Fact

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