News Releases

August 27, 2003

Dainippon Licenses Out an Antidementia Agent

August 27, 2003--- Dainippon Pharmaceutical Co., Ltd. (President: Kenjiro Miyatake) announced today that Dainippon had concluded an agreement to license out Dainippon's original antidementia agent "AC-3933", which is under development in Europe by Dainippon, to Aventis (Head Office located in Strasbourg, France).

Under this agreement, Aventis will receive the exclusive development and marketing rights of AC-3933 for the world, except Japan, with option right for China, Taiwan and South Korea.

AC-3933 is a novel cognitive enhancer, with central benzodiazepine receptor partial inverse agonist properties, which is a different mechanism of action than antidementia agents already launched in the market. Comparing with antidementia agents already marketed, it is expected that AC-3933 demonstrates better efficacy for improving memory deficit, that is a major symptom of dementia, by enhancement of the cholinergic function through the allosteric reduction of GABA activity, as well as by enhancement of the glutamatergic function.

In preclinical pharmacology tests, AC-3933 restored memory deficit at much lower doses than those of current antidementia agents on the market. In addition, AC-3933 improved memory deficit caused by glutamatergic hypofunction; something that current antidementia agents on the market do not show efficacy for. Clinical results in healthy volunteers suggest fewer clinically significant adverse drug reactions, especially related to the gastrointestinal system, such as vomiting, in comparison with currently marketed antidementia agents.

In Europe, with the Phase I clinical studies of AC-3933 completed, Dainippon will initiate a Phase IIa clinical study focusing on Alzheimer dementia this autumn. Aventis will then pursue the subsequent development of AC-3933 in Aventis' licensed territories. In Japan, Dainippon is also in preparation for a Japanese Phase I study.

For Dainippon, AC-3933 is one of its foremost products under development, and Dainippon believes that AC-3933 has the potential to become a key product for Dainippon and Aventis in the global market.

Through this collaboration with Aventis, Dainippon will further speed AC-3933's global development in order to introduce it as a new generation antidementia agent as soon as possible, while also introducing product development synergies for the Japanese market.