AAIC 2025 to Feature Lecanemab Data on Long-Term Efficacy, Real-World Use, and Maintenance Dosing

At the 2025 Alzheimer’s Association International Conference (AAIC), Eisai will present updated clinical and real-world data on lecanemab, including four-year results from the Clarity AD open-label extension trial and data on a subcutaneous formulation under development for maintenance dosing. The conference will be held July 27–31 in Toronto and virtually.

Lecanemab is an anti-amyloid beta protofibril monoclonal antibody approved in 45 countries for the treatment of early Alzheimer disease (AD). The drug targets both soluble protofibrils and insoluble amyloid plaques. Eisai leads the global development and regulatory efforts for lecanemab in collaboration with BioArctic and Biogen.

Among the company’s 50 presentations are three focused symposia, two product theaters, and 21 oral sessions. Key highlights include:

• Clarity AD Four-Year Data: On July 30, updated findings will be shared on the long-term safety and efficacy of lecanemab in participants with early Alzheimer disease who continued treatment in an open-label extension following the Phase 3 Clarity AD trial.
• Subcutaneous Formulation Research: New data will be presented on a weekly subcutaneous formulation of lecanemab for maintenance therapy, including findings on clinical comparability to the intravenous version. A Biologics License Application for the subcutaneous autoinjector is under FDA review with a decision expected by August 31, 2025.
• Real-World Clinical Experience: Two years post-approval, researchers will present case series and observational data on lecanemab’s use in U.S. practice settings, with attention to treatment patterns among patients with comorbidities, differences across racial and ethnic groups, and patient and caregiver perspectives.

Eisai will also share preliminary findings from the DIAN-TU-001 NexGen trial, evaluating etalanetug (E2814), an investigational anti-tau antibody, in combination with lecanemab for patients with dominantly inherited Alzheimer disease.

According to the company, lecanemab’s clinical strategy includes intravenous initiation followed by maintenance therapy and exploration of subcutaneous administration to improve treatment flexibility and patient access. Additional sessions will address biomarker development, implementation science, and statistical modeling in AD trials.

Lecanemab’s mechanism of action targets amyloid beta protofibrils, which are thought to be the most neurotoxic species and a key contributor to disease progression and cognitive decline. Research suggests that their reduction may help preserve neuronal integrity and slow functional impairment.

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