Long-Term Persistence and Patient Characteristics for Intravenous and Subcutaneous Lecanemab in Real-World Use in the United States

This study aims to describe demographics, clinical characteristics, and adherence/persistence patterns of U.S. patients treated with lecanemab beyond 18 months. This observational study used open administrative claims from PurpleLab database to identify patients who had ≥1 lecanemab claim (IV or SC) between January 6, 2023 and December 20, 2025, and had continuous clinical activity for ≥6 months prior to lecanemab initiation. The observation period ran from first lecanemab infusion to latest data availability. We examined long-term treatment persistence, among those who initiated lecanemab in 2023 and maintained ≥20 months of continuous clinical activity. A total of 9,205 patients treated with IV lecanemab were included, with mean observation period of 388.9 days. Patients who had ≥2 lecanemab infusions received a mean of 1.7 (SD 0.3) doses per month within the first 18 months of treatment. The 44 patients receiving SC maintenance dosing had similar characteristics to IV-treated patients. Of the 336 patients who initiated lecanemab in 2023 and maintained ≥20 months of continuous clinical activity, 77.7% reached 18 months of treatment, and among these, 92.0% remained on lecanemab at 20 months. Further updated analyses will be presented to clarify RW use of SC lecanemab.