TLDR
- Biogen stock falls as LEQEMBI study reports strong long-term patient stability.
- LEADER study shows 82.5% stayed stable or improved during treatment period.
- LEQEMBI maintenance dosing continued supporting disease stage stability.
- Safety findings matched FDA label with mostly mild ARIA cases reported.
- Eisai and Biogen present real-world Alzheimer’s data at AAIC 2026 event.
Biogen Inc. shares traded at $190.30, down 8.96%, during Tuesday morning trading. The decline came as Eisai and Biogen released new real-world data for LEQEMBI at the Alzheimer’s Association International Conference 2026. The findings showed sustained cognitive stability among patients receiving long-term treatment for early Alzheimer’s disease.
LEADER study reports sustained disease stability in early Alzheimer’s patients
The LEADER study evaluated LEQEMBI use across 13 clinical sites in the United States. Researchers analyzed deidentified medical records from patients receiving routine treatment. The interim analysis included 432 patients who completed at least seven LEQEMBI infusions by May 2026.
The study found that disease stage could be evaluated in 427 participants. Among those patients, 82.5% remained stable or improved throughout treatment.75.9% remained in the same disease stage while 6.6% improved from mild Alzheimer’s dementia to mild cognitive impairment.
Patients received LEQEMBI for an average of 520 days and completed an average of 26 doses. Nearly 87% continued treatment during the study period. The results remained consistent across sex, race, ethnicity, and APOE genotype groups.
The analysis also examined patients carrying the APOE ε4 gene variant. Stable or improved disease stages appeared in 81.7% of heterozygotes and 81.0% of homozygotes. These findings showed similar treatment outcomes across genetic risk groups.
Alzheimer’s disease remains a progressive neurological condition that gradually affects memory and daily functioning. LEQEMBI targets amyloid beta plaques and soluble protofibrils linked to disease progression. Continued treatment aims to slow cognitive decline and extend the early stage of Alzheimer’s disease.
Maintenance therapy and safety findings remained consistent with approved labeling
Researchers also reviewed outcomes after patients transitioned to maintenance treatment. A total of 155 patients moved to once-every-four-weeks intravenous maintenance therapy. Another 14 patients transitioned to once-weekly subcutaneous maintenance dosing.
Among intravenous maintenance patients, 72.3% remained stable while 8.4% improved during continued treatment. Meanwhile, 12 of 14 patients receiving subcutaneous maintenance maintained their disease stage. These findings supported continued treatment beyond the initial dosing schedule.
Safety observations aligned with the current U.S. Food and Drug Administration prescribing information. Amyloid-related imaging abnormalities appeared in 12.3% of patients overall. Most reported cases remained asymptomatic and showed mild radiographic severity.
ARIA-E occurred in 6.3% of patients while ARIA-H appeared in 7.9%. No new ARIA-E events, macrohemorrhages, or intracerebral hemorrhages larger than one centimeter occurred during intravenous maintenance therapy. No severe ARIA cases appeared among APOE ε4 homozygotes.
Researchers also assessed patients using anticoagulant or antiplatelet therapies. A total of 106 patients received antithrombotic medications during the study period. The incidence of ARIA remained similar between patients using these medications and those without antithrombotic treatment.
Eisai and Biogen continue global commercialization of LEQEMBI
LEQEMBI remains a jointly commercialized treatment developed by Eisai and Biogen. Eisai leads global development and regulatory submissions while both companies co-promote the therapy. Eisai also retains final decision-making authority for the product.
The LEADER study represents a three-year multicenter real-world evaluation of LEQEMBI use in clinical practice. Besides measuring treatment persistence, researchers examined safety, healthcare implementation, and functional outcomes. The current analysis reflects interim findings collected across diverse U.S. treatment centers.
The latest results add real-world evidence to previous clinical trial data supporting LEQEMBI in early Alzheimer’s disease. They also provide additional information on long-term treatment patterns and maintenance dosing. The findings expand available evidence for clinicians managing patients with mild cognitive impairment due to Alzheimer’s disease and mild Alzheimer’s dementia.
Get 3 Free Stock Ebooks
Discover top-performing stocks in AI, Crypto, and Technology with expert analysis.
- Top 10 AI Stocks - Leading AI companies
- Top 10 Crypto Stocks - Blockchain leaders
- Top 10 Tech Stocks - Tech giants
