Amyloid PET Changes During Lecanemab Treatment in Patients With and Without Amyloid-related Imaging Abnormalities

Lecanemab reduces cerebral amyloid-β burden in Alzheimer disease, but whether amyloid-related imaging abnormalities (ARIA) are associated with greater amyloid clearance remains unclear. We report 3 patients with comparable clinical backgrounds and similar baseline cognitive performance who underwent amyloid-β PET before and after lecanemab treatment. Quantitative analysis using Centiloid showed a greater reduction in amyloid burden in the patient who developed ARIA than in the 2 patients without ARIA. These observations suggest ARIA may be associated with more pronounced treatment-related amyloid clearance, warranting further investigation in larger cohorts.