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 * KNOTT DAVID M   2. Issuer Name and Ticker or Trading Symbol ARROWHEAD RESEARCH CORP [ARWR] 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) 485 UNDERHILL BLVD, STE 205 3. Date of Earliest Transaction (Month/Day/Year) 08/16/2006 (Street) SYOSSET, NY 11791-3419 4. If Amendment, Date Original Filed(Month/Day/Year) 08/18/2006 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ 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 08/16/2006   P   19,000 A $ 4.88 752,800 I By Shoshone Partners, L.P. (1) (3) Common Stock 08/16/2006   P   4,300 A $ 4.88 4,300 I By Mulsanne Partners, L.P. (1) (3) Common Stock 08/16/2006   P   74,450 A $ 4.88 1,813,631 I By Knott Partners Offshore Master Fund, L.P. (1) (3) (4) Common Stock 08/16/2006   P   4,500 A $ 4.88 44,800 I By Managed Account (2) (3)

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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
KNOTT DAVID M 485 UNDERHILL BLVD STE 205 SYOSSET, NY 11791-3419		X

Signatures

/s/ David M. Knott		01/23/2007
**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)	The Reporting Person is the managing member of Knott Partners, Management, LLC, which is the sole general partner of Shoshone Partners, Knott Partners Offshore Master Fund, L.P. and Mulsanne Partners, L.P.
(2)	The entry represents securities of the issuer held by a managed account for which Dorset Management Corporation provides investment management services (the "Managed Account").
(3)	As a result of the Reporting Person's interests in Knott Partners Management, LLC and in Dorset Management Corporation, the Reporting Person has investment discretion and control of the securities represented in this entry. The Reporting Person may be deemed to beneficially own an indirect pecuniary interest in the securities represented in this entry as a result of its performance-related fee. Except with respect to Shoshone Partners, L.P., in which the Reporting Person owns a beneficial interest, the Reporting Person disclaims beneficial ownership therein except to the extent ultimately realized. Each of Shoshone Partners, L.P., Mulsanne Partners, L.P., Knott Partners Offshore Master Fund, L.P., and the Managed Account disclaims beneficial ownership of securities reported as owned by any other party.
(4)	This amendment filing is being made to reflect the transfer by Matterhorn Offshore Fund Limited to Knott Partners Offshore Master Fund, L.P. of record ownership of the securities reported in this entry. This amendment does not reflect any change of any pecuniary interest in these securities.

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