For Immediate Release

Company name: DAIICHI SANKYO COMPANY, LIMITED
Representative: Takashi Shoda, President and Representative Director
(Code no.: 4568, First Section, Tokyo, Osaka and Nagoya Stock Exchanges)
Please address inquiries to Toshiaki Sai, General Manager,
Corporate Communications Department
Telephone: +81-3-6225-1126
http://www.daiichisankyo.com/

DAIICHI SANKYO COMMENCES PATENT LITIGATION AGAINST MYLAN AND MATRIX IN THE UNITED STATES

Tokyo, June 5, 2008 - DAIICHI SANKYO COMPANY, LIMITED, announced today that Daiichi Sankyo and its U.S. subsidiary, DAIICHI SANKYO, INC.,commenced litigation on June 3, 2008 against Mylan and its subsidiary, Matrix*,
in the United States District Court for the District of New Jersey for infringement of Daiichi Sankyo's U.S. patent covering olmesartan medoxomil, one of the active ingredients in Daiichi Sankyo's antihypertensive drug, AZOR(TM). Matrix has filed an Abbreviated New Drug Application ("ANDA") with the United States Food and Drug Administration seeking to market a generic version of AZOR(TM).
Daiichi Sankyo and DSI intend to vigorously defend the patent, which expires in April 2016 in the United States.
Olmesartan medoxomil, one of the active ingredients in AZOR(TM), is an angiotensin II receptor antagonist that Daiichi Sankyo independently developed, and is marketed in over 50 countries as an antihypertensive drug which suppresses vasoconstriction by affecting the rennin-angiotensin system to control blood pressure.

*Note:
"Mylan" refers to Mylan Inc. (HQ: Pennsylvania) and "Matrix" refers to Matrix Laboratories, Limited (HQ: India), a subsidiary of Mylan.