Catalyst Pharmaceuticals Inc. announced that it has entered into a definitive agreement with Eisai Co., Ltd. (Eisai) under which Catalyst will acquire the U.S. rights for FYCOMPA(R) (perampanel) CIII and an exclusive option period to review, evaluate and negotiate to acquire a rare epilepsy asset currently in Eisai's pipeline. The acquisition adds a highly complementary and established marketed product in neurology that diversifies Catalyst's commercial product portfolio and paves the way for further expansion into other rare neurological diseases that address critical unmet medical needs.