Overview. Name: Leqembi Synonyms: Lecanemab-irmb, BAN2401, mAb158 Therapy Type: Immunotherapy (passive) Target Type: Amyloid-Related Condition(s): Alzheimer's Disease U.S. FDA Status: Alzheimer's Disease (Approved) Company: BioArctic AB, Biogen, Eisai Co., Ltd. Background. BAN2401 is the humanized IgG1 version of the mouse monoclonal antibody mAb158, which selectively binds to large, soluble ...