Arrowhead Announces Private Placement of $2 Million

PASADENA, Calif.--(Business Wire)--
Arrowhead Research Corporation (NASDAQ:ARWR) today announced that it has
obtained commitments from selected institutional and accredited investors to
purchase at least $2 million of common stock and warrants in a private placement
transaction.

Under the terms of the offering, Arrowhead will sell at least 7.1 million units
at a purchase price of $0.30 per unit, with each unit consisting of one share of
common stock and a warrant to purchase one additional share of common stock at
an exercise price of $0.50 per share. The offering is expected to close no later
than July 16, 2009, subject to customary closing conditions.

This press release does not and shall not constitute an offer to sell or the
solicitation of any offer to buy any of the securities, nor shall there be any
sale of the securities, in any state or jurisdiction in which such offer,
solicitation or sale would be unlawful prior to the registration or
qualification under the securities laws of any state.

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

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