Biogen and Eisai present real-world data at AD/PD 2026 showing strong long-term persistence with lecanemab (Leqembi), with most Alzheimer’s patients continuing therapy beyond 18 months.
Written By: Chikkula Pavan Kumar, PharmD
Reviewed By: Pharmacally Editorial Team
Biogen and Eisai have presented new real-world data on long-term treatment persistence with the anti-amyloid antibody Lecanemab at the International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders 2026 in Copenhagen, Denmark, showing that most patients continue therapy beyond the initial 18-month treatment period in routine clinical practice.
The analysis evaluated treatment persistence and baseline characteristics among patients receiving intravenous lecanemab, marketed as Leqembi, for early Alzheimer’s disease.
Researchers conducted a retrospective observational study using the PurpleLab CLEAR Claims database, which compiles U.S. medical insurance claims data. The analysis included 13,388 individuals who received at least one intravenous dose of lecanemab between January 6, 2023, and November 30, 2025. Of these, 10,763 patients met the criteria for continuous healthcare engagement and were included in the primary dataset.
At baseline, the mean age of patients was 73.8 years and 56.5% were female. The most commonly reported comorbidities were dyslipidemia (42.2%) and hypertension (36.9%). Patients were followed for an average of 350.9 days. Treatment patterns were largely consistent with the recommended dosing schedule, with an average of 1.7 administrations per month and a mean dosing interval of 16.4 days (median 14 days).
To assess long-term persistence beyond the initial treatment phase, investigators analyzed a subgroup of 371 patients who initiated therapy in 2023 and had at least 20 months of continuous follow-up. Using Kaplan–Meier analysis, researchers found that 78.4% of patients remained on lecanemab therapy at 18 months, 71.7% at 20 months, and 67.3% at 24 months.
Among those who remained on treatment at the 18-month mark, the majority continued therapy during the maintenance phase beyond this period, indicating sustained adherence in real-world clinical practice. Patient characteristics and dosing patterns observed in the claims-based analysis were also broadly consistent with those reported in clinical studies.
Investigators further noted that treatment persistence remained relatively high despite potential factors that could delay dosing, including MRI monitoring requirements, adverse events, and logistical challenges associated with infusion therapy.
Globally, lecanemab has been approved in more than 50 countries and regions, including the United States, Japan, China, and the European Union. Following the initial 18-month treatment phase with biweekly infusions, a monthly intravenous maintenance regimen has been authorized in several markets. Additional regulatory filings for subcutaneous formulations are under review, including a U.S. supplemental Biologics License Application currently under Priority Review with a PDUFA action date of May 24, 2026.
Lecanemab originated from a research collaboration between BioArctic and Eisai. Eisai leads global development and regulatory submissions, while Eisai and Biogen jointly commercialize and promote the therapy.
Reference
Real-World LEQEMBI Data Shows Patients Choose to Stay on Long-Term Treatment, 20 March 2026, Results from Real-World, Long-Term Treatment Persistence with LEQEMBI® (lecanemab-irmb) in the United States Presented at AD/PD™ 2026 | Biogen
About the Writer
Chikkula Pavan Kumar, PharmD is a Doctor of Pharmacy with a keen interest in clinical pharmacy, pharmacovigilance, and evidence-based practice. In his words, he is passionate about patient safety and translating complex medical information into clear, research-driven communication.