Long-Term Data Confirm Leqembi Treatment Adherence in Real-World Use
Key Takeaways:
- In real-world US claims data, most individuals receiving lecanemab remained on treatment beyond 18 months.
- Dosing patterns in clinical practice were consistent with the recommended every-2-week regimen, with minimal disruption from MRI monitoring or adverse events.
Real-world US claims data show that most individuals who initiate intravenous (IV) Leqembi (lecanemab-irmb; Eisai, Tokyo, Japan; Biogen, Cambridge, MA) remain on treatment beyond 18 months. The findings, presented at the 20th International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders (AD/PD 2026), are the first real-world data on treatment persistence beyond 18 months reported for Leqembi in clinical settings, providing insight the long-term use of this anti-amyloid-β protofibril antibody in routine clinical practice.
The retrospective observational study used the PurpleLab CLEAR Claims database, a US-based medical insurance claims dataset, to analyze data from 10,763 patients (mean age: 73.8 years; 56.5% female) who met the criteria for continuous healthcare encounters out of 13,388 individuals who received at least one IV dose of Leqembi between January 6, 2023, and November 30, 2025. The most common comorbidities were dyslipidemia (42.2%) and hypertension (36.9%), and the mean follow-up was 350.9 days. Long-term persistence was assessed using the Kaplan–Meier method in a subgroup of 371 patients who initiated treatment in 2023 and had at least 20 months of continuous follow-up.
Key findings include:
- 78.4% of patients remained on Leqembi at 18 months.
- 71.7% continued treatment at 20 months.
- 67.3% continued treatment at 24 months.
- Average dosing frequency was 1.7 administrations per month, with a mean interval of 16.4 days (median: 14 days), consistent with the recommended 2-week (Q2W) dosing schedule.
- Patient characteristics and dosing patterns generally aligned with those observed in the phase 3 Clarity AD trial (NCT03887455).
- MRI monitoring requirements and adverse events did not substantially disrupt dosing continuity.
Source: Eisai. Results from real-world, long-term treatment persistence with Leqembi (lecanemab-irmb) in the United States presented at AD/PD 2026. Press release. Published March 20, 2026. Accessed March 25, 2026. https://media-us.eisai.com/2026-03-20-Results-from-Real-World,-Long-Term-Treatment-Persistence-with-LEQEMBI-R-lecanemab-irmb-in-the-United-States-Presented-at-AD-PD-TM-2026