Eisai Co., Ltd. is a Japan-based pharmaceutical company headquartered in Tokyo that discovers, develops, manufactures, and markets small‑molecule and biologic medicines. The company’s core therapeutic areas are oncology and neurology.
Eisai’s portfolio includes anticancer agents such as lenvatinib (Lenvima, co-developed and co-commercialized with Merck & Co., Inc., known as MSD outside the U.S. and Canada) and eribulin (Halaven), as well as neurology products including donepezil (Aricept), perampanel (Fycompa), and lecanemab (Leqembi, developed with Biogen) for Alzheimer’s disease. The company operates R&D and manufacturing sites in Japan, the Americas, Europe, and Asia and supplies medicines in markets worldwide. Eisai is listed on the Tokyo Stock Exchange (ticker: 4523).
