On December 20, 2012, Arrowhead Research Corporation announced and commented on its fourth quarter and year-end financial results for the period ended September 30, 2012. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated by reference herein.

In accordance with General Instruction B.2 of Form 8-K, the information in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof, except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

(d) Exhibits

              Exhibit No.   Description

                 99.1       Press Release, dated December 20, 2012.


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