Lecanemab Therapy Use Patterns for Alzheimer's Disease Among Early Initiators in a Large National Health Plan.

BACKGROUND: Lecanemab, an anti-amyloid monoclonal antibody, has been approved for treatment of early Alzheimer's disease. However, real-world data remain limited regarding use. METHODS: Using data from a large national health plan with primarily Medicare Advantage enrollees, we characterized demographic and clinical characteristics in the 6 months preceding the initial infusion among individuals who initiated lecanemab between 1/1/2023 and 06/30/2024. We also characterized the patterns of infusions and the timing of MRIs for safety monitoring following the initial infusion among initiators who had ≥ 3 months of follow-up. We further assessed trends in lecanemab use between 1/1/2023 and 12/31/2024. RESULTS: Of the 195 lecanemab initiators, the average age was 74.6 (SD = 5.5) years, 62.1% were female, 87.7% were White, 4.1% were Black, 1.5% were Hispanic, and 98.5% were on a Medicare Advantage plan. Almost all initiators resided in nonrural areas (96.4%); 2.6% used anticoagulants, and 1.5% used antiplatelets. Among the 119 initiators who had ≥ 3 months of follow-up, 40 (33.6%) received 7 total infusions, the expected number of infusions based on the recommended schedule of every 2 weeks. From the initial infusion, the average number of days to the first MRI was 47.1 (SD = 15.8), and to the second MRI scan was 73.4 (SD = 12.0) days, consistent with the recommended schedule. During 2023-2024, there were 526 patients who had ever received lecanemab. The increase in new initiators was modest over 2024, with only 43 more initiators during the final (n = 137) versus the first quarter (n = 94) of 2024. CONCLUSIONS: This study demonstrated slow uptake of lecanemab among Medicare Advantage beneficiaries. Adherence to the ideal treatment schedule was less than recommended. Early lecanemab users were not representative of the population likely eligible for treatment nationally. Further research is warranted to track longer-term trends in utilization, as well as reasons for treatment interruption or discontinuation in real-world populations.