Effectiveness, safety, and biomarker dynamics of lecanemab in Chinese Alzheimer's disease population: a multicenter real-world study.

BACKGROUND: Lecanemab, an anti-amyloid beta (Aβ) protofibril antibody, was introduced in China in 2024, but its real-world performance remains unknown. METHODS: In this prospective, multicenter study across 21 sites, 261 Alzheimer's disease patients (mild cognitive impairment to moderate dementia) received biweekly lecanemab (10 mg/kg). A matched Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort served as comparator. Cognitive tests, plasma biomarkers, and optional amyloid/tau positron emission tomography (PET) were assessed over 6 months. RESULTS: Lecanemab significantly attenuated cognitive decline versus ADNI. Plasma Aβ42, Aβ40, phosphorylated tau 217 (p‑tau217), glial fibrillary acidic protein (GFAP), and ratios showed robust changes; a p‑tau217 reduction correlated with amyloid PET clearance (mean -22.1 Centiloid; 29.2% turned amyloid-negative). Apolipoprotein E (APOE) ε4 non-carriers showed greater improvements. Infusion reactions occurred in 11.1% and amyloid-related imaging abnormalities in 9.2% (1.6% symptomatic), with no stage-related safety differences. CONCLUSION: Lecanemab was effective and well tolerated in real-world Chinese patients. Plasma p‑tau217 may serve as a sensitive, minimally invasive treatment-response biomarker.