Lecanemab is a monoclonal antibody treatment for early Alzheimer’s disease that targets beta-amyloid, helping clear plaques from the brain. It is given as an intravenous infusion every two weeks and has been shown to modestly slow cognitive and functional decline in clinical trials. The therapy is approved for use in patients with mild cognitive impairment or mild dementia due to Alzheimer’s. The most important risks include amyloid-related imaging abnormalities (ARIA), such as brain swelling or microbleeds, so patients require regular MRI monitoring. While not a cure, lecanemab is considered a disease-modifying therapy that offers a new option in early-stage treatment.