Sepracor and Eisai to sell eszopiclone in Japan

US research-based pharmaceutical company Sepracor has signed an agreement with Japanese drugmaker Eisai that will focus on the commercialization of the former's insomnia treatment eszopiclone, which is marketed in the USA as Lunesta.

Under the terms of the agreement, financial details of which were not made public, Eisai will be responsible for conducting the necessary clinical trials to attain clearance for the drug in its home territory, in return for exclusive marketing rights if it is successfully commercialized. Sepracor, which is entitled to receive an initial fee, developmental milestone payments and royalties on eventual product sales, predicted that Eisai would file for Japanese registration of the drug in 2010 or 2011. In addition, the US firm will receive compensation for supplying the drug's active ingredient.

Lunesta, which has been commercially available in the USA since 2005 (Marketletters passim), provided revenues of approximately $566.8 million last year. In Japan, insomnia is thought to affect around 24 million people, although only an estimated seven million are currently receiving treatment. Sepracor said that the country's sedative hypnotic market could be worth as much as $500.0 million a year.