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PRESS RELEASE
November 10, 2005

Nanotech Company Arrowhead Names Dr. Leon Ekchian President; Experienced Leader Has Background in Science and Commercialization

PASADENA, California – (BUSINESS WIRE) – Nov. 10, 2005 – Arrowhead Research Corporation (Nasdaq:ARWR), a diversified nanotechnology company, today announced the appointment of Dr. Leon Ekchian as president. Dr. Ekchian, armed with both an MBA from UCLA and a Ph.D. from MIT, is a tested business leader who also has a deep understanding of the science that underlies innovation.

For the last nine years, Dr. Ekchian served as president and chief executive officer of Litex Inc., a Lockheed Martin spinoff focused on the commercialization of advanced electronic automotive technologies.

Dr. Ekchian's responsibilities will include overseeing the day-to-day operations of Arrowhead's subsidiaries, making sure they move swiftly toward the goal of commercializing their innovations. He will also develop Arrowhead's long-term strategic plan as it launches more companies and obtains key intellectual property.

"Arrowhead is very fortunate to attract a president with Leon's particular combination of skills," said R. Bruce Stewart, Arrowhead's chairman. "He has just the right kind of background we need in finance, business, private equity and technology. I'm thrilled with this appointment."

Dr. Ekchian praised Arrowhead's "extremely compelling" business model. "Arrowhead is an innovator in developing and executing in the nanotech field. In addition, the company has assembled a very talented team of managers and technical staff. I am really excited about working with this team and about the future of Arrowhead."

Dr. Ekchian's tenure at Litex began in 1997, when Lockheed Martin spun the company off to commercialize auto emissions reduction technology. Dr. Ekchian was previously a business development executive responsible for Lockheed Martin's business/corporate development and strategic planning. While at Litex, Ekchian focused on commercialization while also overseeing sales, product development, engineering, licensing and finance. He spearheaded an aggressive marketing and sales campaign on three continents, serving as the primary company contact to the media and investors. And, at the same time, Dr. Ekchian secured venture capital and private equity financing.

Dr. Ekchian received his MBA in 1992 from the University of California, Los Angeles, with a concentration in finance, marketing and strategy. He earned his bachelor's and master's of science in addition to his Ph.D. (1983) from the Massachusetts Institute of Technology.

About Arrowhead Research Corporation

Arrowhead Research Corporation (www.arrowheadresearch.com) is a publicly-traded 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 four subsidiaries commercializing nanotech products and applications, including anti-cancer drugs, RNAi therapeutics, 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 recent economic slowdown affecting technology companies, the future success of our scientific studies, our ability to successfully develop products, rapid technological change in our markets, changes in demand for our future products, legislative, regulatory and competitive developments and general economic conditions. Our Annual Report on Form 10-K and 10-K/A, recent and forthcoming Quarterly Reports on Form 10-Q and 10-Q/A, recent Current Reports on Forms 8-K and 8-K/A, our Registration Statement on Form S-3, and other SEC filings discuss some of the 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.

Contacts

R. Bruce Stewart, President
Telephone: 626.792.5549
Email: bruce@arrowres.com

Virginia Dadey; Vice President, Investor Relations
Telephone: 212.541.3707
Email: vdadey@arrowres.com