Dainippon Pharmaceutical Co, Ltd and Eisai Co, Ltd have concluded an exclusive agreement for the development, manufacture and marketing of zonisamide (generic name) in 14 Asian countries including China and Taiwan, recently. Zonisamide is an anti-epileptic treatment created by Dainippon Pharmaceutical.

Zonisamide is an anti-epileptic agent characterized by a wide anti-seizure spectrum which is even effective against intractable epilepsy. In Japan, the drug was approved in 1989 and is marketed by Dainippon Pharmaceutical under the brand name Excegran. In the other Asian territories, the product was launched by Dong-A Pharmaeutical Co., Ltd. in 1992 in South Korea, and Eisai Korea Inc. has been marketing the product since the acquisition of marketing rights on February 25, 2005.

In the United States and Europe, Elan Corporation, plc. had licensed zonisamide from Dainippon Pharmaceutical and had since marketed it under the product name Zonegran in the US while continuing development in Europe. In March 2004, Eisai obtained manufacturing, development and marketing rights for Zonegran upon the completion of an strategic product acquisition agreement with Elan. Currently in the US, Eisai Inc., a subsidiary in the US, markets the drug under the name Zonegran, which has been successfully penetrating the US market. In Europe, an Eisai UK subsidiary, Eisai Ltd. obtained marketing authorization approval of Zonegran from the European Commission on March 10, and will develop and expand Zonegran business in the enlarged EU market.

Dainippon Pharmaceutical and Eisai Co., Ltd. expect that through this territorial expansion agreement, Eisai will also expand business opportunities in Asian countries by utilizing its marketing expertise accumulated through experience in the US and Europe to fulfil patients' needs and make further contributions to the benefits that the drug can provide throughout the Asian region.