Arrowhead Announces Option Grant to CEO under NASDAQ Marketplace Rule 4350

Business Wire, Jan 25, 2008

PASADENA, Calif. -- Arrowhead Research Corporation (Nasdaq: ARWR) announced today that in accordance with NASDAQ Marketplace Rule 4350(i)(1)(A)(iv), the Compensation Committee of the Board of Directors approved an inducement grant of a stock option to Christopher Anzalone, Arrowhead's new President and Chief Executive Officer. On December 3, 2007, Dr. Anzalone was granted an option to purchase 2,000,000 shares of the common stock of Arrowhead at an exercise price of $3.92, the closing price of Arrowhead's shares on that date. The option will vest with respect to 1/8 of the shares on the six month anniversary of his date of hire, June 1, 2008, with the balance vesting in 42 equal monthly installments. The option was granted outside Arrowhead's equity incentive plans and as a material inducement to Dr. Anzalone's employment with the company.

The grant was previously disclosed in a Current Report on Form 8-K filed with the Securities and Exchange Commission on December 4, 2007. This release is being issued to comply with NASDAQ Marketplace Rule 4350(i)(1)(A)(iv).

About Arrowhead Research Corporation

Arrowhead Research Corporation (www.arrowheadresearch.com) (NASDAQ:ARWR) is a leading nanotechnology company commercializing new technologies in the areas of life sciences, electronics and energy. Arrowhead is building value for shareholders through the progress of majority owned subsidiaries founded on nanotechnologies originally developed at universities. The company works closely with universities to source early stage deals and to generate rights to intellectual property covering promising new nanotechnologies. Currently, Arrowhead has five subsidiaries commercializing nanotech products and applications, including anti-cancer drugs, RNAi therapeutics, fullerene anti-oxidants, carbon-based electronics and compound semiconductor materials.

Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995:

This news release contains forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. These statements are based upon our current expectations and speak only as of the date hereof. Our actual results may differ materially and adversely from those expressed in any forward-looking statements as a result of various factors and uncertainties, including the future success of our clinical studies, our ability to successfully develop and manufacture products, rapid technological change in our industry, changes in demand for our future products, legislative, regulatory and competitive developments and general economic conditions. Our Annual Report on Form 10-K, and other SEC filings discuss these and other important risk factors that may affect our business, results of operations and financial condition. We undertake no obligation to revise or update publicly any forward-looking statements for any reason.