OSI Pharmaceuticals Announces That the Prior Revocation of Its European DP-IV Patent...

OSI Pharmaceuticals Announces That the Prior Revocation of Its European DP-IV Patent Has Been Upheld

- No Impact on DP-IV Patent Estate Revenue Guidance for 2008 -
MELVILLE, N.Y.--(Business Wire)--
OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) announced today that the
decision of the European Patent Office (EPO) to revoke one of the
Company's dipeptidyl peptidase IV (DP-IV) patents, EP0896538, claiming
the use of DP-IV inhibitors to treat type II diabetes and related
indications, has been upheld in appeal proceedings brought by the
Company.

"We are disappointed with the outcome of the appeal proceedings.
However, since the revocation applies to only one patent within our
licensed DP-IV patent portfolio, any short-term loss in royalty
revenue in Europe should be mitigated as additional licensed patents
within the portfolio progress through the EPO examination procedure to
grant," stated Anker Lundemose, M.D., Ph.D., President of (OSI)
Prosidion. "The Company's DP-IV patent estate includes licensed rights
to patents and patent applications claiming combinations of DP-IV
inhibitors with other oral anti-diabetes drugs such as metformin."

"The Company anticipates that the vast majority of DP-IV sales in
2008 and 2009 are likely to take place in the US, therefore the
financial implications of losing this patent in Europe are relatively
insignificant and do not impact our prior DP-IV revenue guidance for
2008," stated Michael G. Atieh, Executive Vice President and Chief
Financial Officer.

Background

OSI through its U.K. subsidiary, Prosidion Limited, owns or has
licensing rights to issued and pending patents and patent applications
with claims covering DP-IV as a target for anti-diabetes therapy and
related indications. The patents which are subject of these DP-IV
licenses will expire between 2017 and 2019. Thirteen pharmaceutical
companies, including Merck & Co., Inc., Novartis AG and Bristol-Myers
Squibb Company have taken licenses to this patent estate.

About OSI Pharmaceuticals

OSI Pharmaceuticals is committed to "shaping medicine and changing
lives" by discovering, developing and commercializing high-quality and
novel pharmaceutical products designed to extend life and/or improve
the quality of life for patients with cancer and diabetes/obesity. The
Company's oncology programs are focused on developing molecular
targeted therapies designed to change the paradigm of cancer care.
OSI's diabetes/obesity efforts are committed to the generation of
novel, targeted therapies for the treatment of type 2 diabetes and
obesity. OSI's flagship product, Tarceva(R) (erlotinib), is the first
drug discovered and developed by OSI to obtain FDA approval and the
only EGFR inhibitor to have demonstrated the ability to improve
survival in both non-small cell lung cancer and pancreatic cancer
patients in certain settings. OSI markets Tarceva through partnerships
with Genentech, Inc. in the United States and with Roche throughout
the rest of the world. For additional information about OSI, please
visit http://www.osip.com.

This news release contains forward-looking statements. These
statements are subject to known and unknown risks and uncertainties
that may cause actual future experience and results to differ
materially from the statements made. Factors that might cause such a
difference include, among others, challenges to OSI's intellectual
property, any adverse litigation decisions, competition from other
pharmaceutical companies, the ability to effectively market products,
OSI's and its collaborators' abilities to successfully develop and
commercialize drug candidates, the completion of clinical trials, the
FDA review process and other governmental regulation, and other
factors described in OSI Pharmaceuticals' filings with the Securities
and Exchange Commission.

OSI Pharmaceuticals, Inc.
Kathy Galante (investors/media)
Senior Director
or
Kim Wittig (media)
Director
631-962-2000
or
Burns McClellan, Inc. (representing OSI)
Justin Jackson (media)
Kathy Nugent (media)
212-213-0006

Copyright Business Wire 2008