Nihon Eisai Co. Ltd. was established in 1941. In 1944, merger with Sakuragaoka Research Laboratory resulted in creation of Eisai Co. Ltd. The American subsidiary of the company, Eisai Inc., was established in 1995. On November 25, 1996, Eisai received
approval from the United States
Food and Drug Administration (USFDA) for Aricept (
donepezil), a drug discovered in the company's labs and co-marketed with
Pfizer. Three years later in 1999, the company received USFDA approval for Aciphex (
rabeprazole), a drug co-marketed with
Johnson & Johnson. In September 2006, the company acquired four oncology products from
Ligand Pharmaceuticals. In April 2007, Eisai acquired
Exton, Pennsylvania-based Morphotek, a company developing
therapeutic monoclonal antibodies for the treatment of cancer, rheumatoid arthritis, and infectious diseases. In December 2007, Eisai acquired
MGI Pharma, a company specializing in oncology, for US$3.9 billion. This event brought Dacogen (
decitabine), Aloxi (
palonosetron), Hexalen (
altretamine) for ovarian cancer, and the Gliadel Wafer (
carmustine) for brain tumors into the Eisai product portfolio. In 2009, Eisai received the Corporate Award from the
National Organization for Rare Disorders (NORD) for the development of Banzel (
rufinamide). In 2010, Eisai's Halaven (eribulin mesylate) was approved for advanced or metastatic breast cancer in the United States, with approvals in the European Union (EU), Japan and Canada following in 2011. In June 2023, the company suffered from a
ransomware attack, causing a shutdown of some of its logistical systems.
Lecanemab, branded as "Leqembi" was approved by the U.S. Food and Drug Administration (FDA) in January 2023 under an Accelerated Approval pathway. The approval was converted into a traditional approval in July 2023. ==Locations==