Eisai Co., Ltd. engages in the research and development, manufacture, sale, and import and export of pharmaceuticals in Japan. It offers Dayvigo, for the treatment of insomnia; Lenvima, an anticancer agent/molecular targeted medicine for the treatment of thyroid cancer, renal cell carcinoma in combination with everolimus, and hepatocellular carcinoma; Methycobal for the treatment of peripheral neuropathy; and Halaven, an anticancer agent for the treatment of breast cancer. The company also provides Jyseleca, a janus kinase inhibitor; Elental, a branched-chain amino acid preparation; Goofice and Movicol for chronic constipation; Fycompa, an antiepileptic agent; Pariet, a proton-pump inhibitor; Aricept, for Alzheimer's disease/Dementia with Lewy bodies; and Chocola BB plus for the preparation vitamin B2. It has strategic collaboration with Bristol Myers Squibb for the co-development and co-commercialization of farletuzumab ecteribulin antibody drug conjugate. Eisai Co., Ltd. was formerly known as Nihon Eisai Co., Ltd. and changed its name to Eisai Co., Ltd. in 1955. Eisai Co., Ltd. was incorporated in 1941 and is headquartered in Tokyo, Japan.