Eisai Co., Ltd. and Biogen Inc. have announced the completion of Eisai's rolling submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for lecanemab-irmb (LEQEMBI®) subcutaneous autoinjector. This new formulation is intended for weekly maintenance dosing in patients with Mild Cognitive Impairment (MCI) or mild dementia stage Alzheimer's disease (early AD), and the application has been granted Fast Track designation by the FDA.
The BLA is based on data derived from the Clarity AD (Study 301) open-label extension (OLE) and modeling of observed data. If approved, the lecanemab autoinjector will allow for administration at home or in medical facilities, with an injection process expected to take approximately 15 seconds. This subcutaneous option is designed to maintain effective drug concentrations, sustaining the clearance of toxic protofibrils even after amyloid-beta (Aβ) plaque has been cleared from the brain.
Clinical Significance of Subcutaneous Lecanemab
Alzheimer's disease is characterized by an ongoing neurotoxic process that continues even after plaque deposition. Data suggest that early and continuous treatment may prolong the therapeutic benefits, even post-plaque clearance. The subcutaneous autoinjector is anticipated to be more user-friendly for patients and caregivers, potentially decreasing the necessity for hospital visits and specialized nursing care compared to intravenous (IV) administration.
Current Regulatory Status and Global Approvals
LEQEMBI is currently approved in the U.S., Japan, China, South Korea, Hong Kong, Israel, UAE, and Great Britain. Eisai has also submitted applications for approval in 10 other countries and regions, including the European Union (EU). The FDA accepted Eisai's Supplemental Biologics License Application (sBLA) for monthly LEQEMBI IV maintenance dosing in June 2024, with a PDUFA action date set for January 25, 2025.
Lecanemab's Mechanism and Clinical Trial Data
Lecanemab, a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody, targets aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). Approvals were based on Phase 3 data from the Clarity AD clinical trial, which met its primary endpoint and all key secondary endpoints with statistically significant results. The trial demonstrated a 27% reduction in clinical decline on the Clinical Dementia Rating Sum of Boxes (CDR-SB) at 18 months compared to placebo (difference, −0.45; 95% CI, −0.67 to −0.23; P<0.001).
