Lecanemab, also known as BAN2401, is an investigational monoclonal antibody developed for the treatment of Alzheimer's disease. Lecanemab targets and binds to amyloid beta (A_) protofibrils, which are believed to play a role in the formation of amyloid plaques in the brains of patients with Alzheimer's disease. By binding to A_ protofibrils, lecanemab aims to reduce the accumulation and aggregation of amyloid plaques in the brain. It is being investigated for the treatment of Alzheimer's disease, specifically in patients with early symptomatic Alzheimer's or individuals with mild cognitive impairment due to Alzheimer's disease.