Exhibit 99.1
AGREEMENT
TO JOINTLY FILE SCHEDULE 13D
The undersigned hereby agree to jointly prepare and file with regulatory
authorities a Schedule 13D and any future amendments thereto reporting each of
the undersigned's ownership of securities of Cougar Biotechnology, Inc. and
hereby affirm that such Schedule 13D is being filed on behalf of each of the
undersigned.
Dated: April 13, 2006 /s/ Xxxxxxx X. Xxxxxxxxx, M.D.
--------------------------------------
Xxxxxxx X. Xxxxxxxxx, M.D.
Horizon BioMedical Ventures, LLC
By: /s/ Xxxxxxx X. Xxxxxxxxx, M.D.
-----------------------------------
Xxxxxxx X. Xxxxxxxxx, M.D.,
Managing Member