AAIC 2025

AAIC 2025: Subcutaneous lecanemab maintenance dosing shows efficacy, safety in early Alzheimer’s disease

August 6, 2025

At AAIC 2025, Eisai and Biogen presented data on an SC autoinjector formulation of lecanemab for maintenance dosing in early Alzheimer’s disease. The investigational 360 mg weekly SC dose was evaluated in patients who had completed 18 months of IV therapy as part of the Clarity AD open-label extension study (NCT03887455).

Results: Weekly SC lecanemab (360 mg) maintained clinical efficacy and biomarker benefits comparable to continued IV dosing, including consistent Clinical Dementia Rating—Sum of Boxes (CDR-SB) scores and amyloid PET findings. At 48 months, outcomes were similar across SC and IV groups, regardless of amyloid status at 18 months. PK/PD data confirmed equivalent drug exposure and amyloid clearance. Safety was favorable, with <1% systemic injection reactions vs. 26% with IV and no amyloid-related imaging abnormality with edema and/or effusion (ARIA-E) cases. Over 95% of users rated the autoinjector as easy to use, supporting its potential for home administration.

Clinical impact: The SC autoinjector offers a more convenient and potentially safer alternative to IV therapy, supporting long-term adherence and reducing treatment burden. If approved, it could expand access and continuity of care for patients with early Alzheimer’s disease.

Sources:

(2025, July 31). Alzheimer’s Association International Conference. Research advances from the 2025 Alzheimer’s Association International Conference. [Press release]. https://aaic.alz.org/releases-2025/highlights-aaic-2025.asp

(2025, July 31). Eisai. New Data Presented at AAIC Demonstrates Investigational LEQEMBI® (lecanemab-irmb) 360 mg Subcutaneous Maintenance Dosing Could Offer a New Option for Ongoing Treatment of Early Alzheimer’s Disease. [News release]. https://www.eisai.com/news/2025/news202553.html