THIS EXCHANGE AGREEMENT (this “ Agreement ”) is dated as of February 25, 2009, by and between Arrowhead
Research Corporation, a Delaware corporation (the “ Corporation ”), and each of Bob G. Gower, Allison Gower Trust, Rachel
Gower Trust, Morganne Gower Trust, William A. McMinn (each, a “ Holder ” and collectively, the “ Holders ”). The
Corporation and each Holder are referred to as a “ Party ” and collectively as the “ Parties ”.
W I T N E S S E T H :
WHEREAS, the Corporation and each of the Holders are shareholders of Unidym, Inc., a Delaware corporation (“ Unidym
WHEREAS, the Holders own shares of Series A Preferred Stock, $0.0001 par value per share, of Unidym ( each, a “ Unidym
Share ” and, collectively, the “ Unidym Shares ”) in the amounts set forth on Exhibit A , attached hereto;
WHEREAS, the Holders each desire to exchange all their Unidym Shares (including any such Holder’s Unidym Shares held
or previously held in escrow but reduced by the number of shares that are subject to the proper exercise of any right of first
refusal) for common stock of the Corporation, $0.001 par value per share (each, an “ Arrowhead Share ” and, collectively the “
Arrowhead Shares ”); and
WHEREAS, the Corporation desires to exchange (the “ Exchange ”) one newly issued and unregistered Arrowhead Share
for each Unidym Share and the agreement of each Holder to certain restrictions on the transfer and sale of any Arrowhead
Shares they receive pursuant to this Agreement (the Arrowhead Shares received in the Exchange, referred to in this Agreement
as the “ Exchanged Shares ”).
NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged,
the parties hereto agree as follows:
1. Exchange .
(a) Exchange Ratio . The Corporation and each Holder hereby agree to exchange at the Closing the Unidym Shares in
the amounts set forth on Exhibit A , attached hereto, for Arrowhead Shares in the following ratio: one Unidym Shar