Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) and Chugai Pharmaceutical Co., Ltd. (Headquarters: Tokyo, Chairman & CEO: Osamu Nagayama, “Chugai”) announced today that Eisai's aquisition of the rights for manufacturing active pharmaceutical ingredients (API) for Japan from F. Hoffman-La Roche Ltd. (Headquarters: Basel, Switzerland, CEO: Severin Schwan, “Roche”) for the insomnia treatment / anaesthesia induction agent flunitrazepam (Eisai product name: Silece®, Chugai product name: Rohypnol®) as well as the marketing authorization held by Chugai for Rohypnol in Japan has been agreed upon by the three companies, and this contract has come into effect.