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/

Start of Phase III Trial on the Anti-influenza Drug CS-8958

Tokyo, November 17, 2008 - Daiichi Sankyo Co., Ltd. today announced that its anti-influenza drug, CS-8958, has started it's pivotal Phase III trial for adults and Phase II/III trial for pediatrics.

CS-8958, a long-acting neuraminidase inhibitor (LANI), was discovered by Daiichi Sankyo and is co-owned with Biota Holdings Limited. CS-8958 is an inhaled formulation for influenza treatment and it is expected that single administration of CS-8958 will be efficacious for the treatment of influenza. CS-8958 shows efficacy against H5N1 avian influenza virus as well as influenza A and B viruses in preclinical tests.

The Phase III clinical trial for adults is designed to test the efficacy and safety of CS-8958 in several hundred adult patients per group who have confirmed, naturally acquired influenza A or B. The trial uses symptom resolution and fever as its end points after a single inhaled dose. In this double-blind non-inferiority study, it is expected to confirm that single inhalation of CS-8958 is equally effective to 75 mg of oseltamivir administered orally twice daily for 5 consecutive days. Also, the safety of CS-8958 will be assessed in this study.
This study was named MARVEL (Multinational Asian Clinical Research for Influenza Virus Extermination on LANI) study, and is being conducted as multinational clinical study in Asia (Japan, Taiwan, Hong Kong, and Korea).

In the Phase II/III for pediatrics, the efficacy of symptom resolution and fever with the same dose regimens as adults will be confirmed.