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 Submits a New Drug Application in Japan for CS-8958, a Long-Acting Neuraminidase Inhibitor for the Treatment of Influenza

Tokyo, Japan (February 1, 2010) - Daiichi Sankyo Company, Limited (hereafter; Daiichi Sankyo), today announced that it has submitted a New Drug Application to the Ministry of Health, Labor and Welfare for approval in Japan of CS-8958, a proprietary anti-flu drug.

CS-8958 is a laninamivir prodrug that is a Long-Acting Neuraminidase Inhibitor. The drug, developed entirely for the Japanese market by Daiichi Sankyo, will be in the form of an inhalant that will directly treat the airways of influenza patients. Clinical studies to date with adults and children suffering from type A or B influenza viruses have proven CS-8958 to be effective with a single administration.

In non-clinical studies, CS-8958 has also demonstrated that it is efficacious with the H1N1 and potentially lethal H5N1 (avian influenza) viruses, leading to an expectation for wide-ranging contributions to influenza treatment in the future.

In November 2009, Daiichi Sankyo began a Phase III clinical study in Japan on the prophylactic use of CS-8958.