The study evaluated the efficacy and safety of lecanemab, a humanized IgG1 monoclonal antibody targeting soluble amyloid-beta (Aβ) protofibrils, in early Alzheimer's disease. The 18-month, multicenter, double-blind, phase 3 trial involved 1795 participants aged 50 to 90 years with mild cognitive impairment or mild dementia due to Alzheimer's disease, who were randomly assigned to receive either lecanemab or placebo. The primary endpoint was the change in the Clinical Dementia Rating-Sum of Boxes (CDR-SB) score from baseline at 18 months. Key secondary endpoints included changes in amyloid burden on PET, cognitive function, and activities of daily living. Results showed that lecanemab significantly reduced the CDR-SB score compared to placebo, indicating less cognitive decline. Additionally, lecanemab reduced brain amyloid burden and improved cognitive and functional measures. However, lecanemab also caused infusion-related reactions and amyloid-related imaging abnormalities. The study concluded that lecanemab reduced amyloid levels and cognitive decline in early Alzheimer's disease but required longer trials to further assess its efficacy and safety.The study evaluated the efficacy and safety of lecanemab, a humanized IgG1 monoclonal antibody targeting soluble amyloid-beta (Aβ) protofibrils, in early Alzheimer's disease. The 18-month, multicenter, double-blind, phase 3 trial involved 1795 participants aged 50 to 90 years with mild cognitive impairment or mild dementia due to Alzheimer's disease, who were randomly assigned to receive either lecanemab or placebo. The primary endpoint was the change in the Clinical Dementia Rating-Sum of Boxes (CDR-SB) score from baseline at 18 months. Key secondary endpoints included changes in amyloid burden on PET, cognitive function, and activities of daily living. Results showed that lecanemab significantly reduced the CDR-SB score compared to placebo, indicating less cognitive decline. Additionally, lecanemab reduced brain amyloid burden and improved cognitive and functional measures. However, lecanemab also caused infusion-related reactions and amyloid-related imaging abnormalities. The study concluded that lecanemab reduced amyloid levels and cognitive decline in early Alzheimer's disease but required longer trials to further assess its efficacy and safety.