UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 3, 2005

Arrowhead Research Corporation

(Exact name of registrant as specified in its charter)

Delaware	0-21898	46-0408024
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

1118 East Green Street, Pasadena, CA	91106
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (626) 792-5549

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.02.  Termination of a Definitive Material Agreement.

On October 3, 2005, Arrowhead Research Corporation (the “Company”) issued to the California Institute of Technology a notice to terminate the sponsored research agreements relating to the work of Dr. Marc Bockrath and Dr. Harry Atwater, dated as of September 29, 2003 and February 23, 2004, respectively. Notice of termination was issued pursuant to the terms of the agreements, and, unless notice of termination is revoked, these agreements will terminate on December 2, 2005.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: October 6, 2005

ARROWHEAD RESEARCH CORPORATION
By:	/s/ Joseph T. Kingsley
	Joseph T. Kingsley, Chief Financial Officer