Biogen (NASDAQ:BIIB) and Eisai, today released new real-world findings from a massive U.S. claims analysis demonstrating high long-term persistence rates for patients receiving intravenous (IV) LEQEMBI® (lecanemab).
The data, presented at the 20th International Conference on Alzheimer's and Parkinson's Diseases (AD/PD™ 2026) in Copenhagen, provides the first large-scale look at how patients adhere to the anti-amyloid therapy in a typical clinical setting outside of controlled trials.
The retrospective study analyzed data from 10,763 treated individuals (mean age 73.8) using the PurpleLab® CLEAR Claims database, covering the period from the drug's initial launch on January 6, 2023, through November 30, 2025.
The results revealed that 78.4% of patients remained on therapy at the 18-month mark—the duration of the pivotal Phase 3 Clarity AD study.
Persistence remained remarkably durable over the long term, with 71.7% of patients staying on treatment at 20 months and 67.3% continuing through 24 months.
The analysis also provided insights into real-world dosing patterns.
The mean dosing interval was found to be 16.4 days, with a median of 14 days, indicating that clinical practice is closely mirroring the bi-weekly schedule established in clinical trials.
With a mean follow-up of 350.9 days across the cohort, the findings suggest that both patients and healthcare providers see significant value in continuing treatment to manage Alzheimer’s as a chronic condition.