Arrowhead Announces CFO Transition

PASADENA, Calif.--(Business Wire)--
Arrowhead Research Corporation (NASDAQ: ARWR) today announced that Paul
McDonnel, the Company`s Chief Financial Officer, intends to resign as the
Company`s Chief Financial Officer in order pursue another opportunity out of the
state. Mr. McDonnel has agreed to serve as Chief Financial Officer of the
Company at least until August 10, 2009 in order to assist with the Company`s
next quarterly report and the quarterly earnings conference call. On July 6,
2009, Joseph T. Kingsley, Arrowhead`s former President and Chief Financial
Officer, was named Vice President of Finance and Accounting and will assist the
Company with executive and financial management until a permanent replacement is
hired.

"We thank Paul for his contributions to the company and are pleased that he will
be staying on part time through our quarterly reporting cycle and as needed as a
consultant," said Dr. Christopher Anzalone, Arrowhead's President and Chief
Executive Officer. "During this transition, we are delighted to report that Mr.
Kingsley will rejoin the Company. He has a long history with Arrowhead and we
welcome his expertise."

About Arrowhead Research Corporation

Arrowhead Research Corporation (www.arrowheadresearch.com) (NASDAQ: ARWR) is a
nanotechnology company commercializing new technologies in the areas of life
sciences, electronics, and energy. Arrowhead is seeking to build value for
shareholders through the progress of majority owned subsidiaries. Currently,
Arrowhead has four subsidiaries commercializing nanotech products and
applications and minority investments in two privately held nanobiotech
companies.

Investor Relations Contacts:
The Piacente Group, Inc.
Kristen McNally
212-481-2050
arrowres@tpg-ir.com

Copyright Business Wire 2009