Eisai and Biogen are targeting a 2025 approval for a subcutaneous formulation of their Alzheimer's disease therapy, Leqembi (lecanemab). The companies have completed their rolling biologics license application (BLA) in the US for the subcutaneous version, which aims to offer a more convenient administration route for patients.
The subcutaneous formulation involves a once-weekly autoinjector following an initial biweekly intravenous induction course. This approach would eliminate the need for hour-long clinic visits required with the current intravenous formulation. If approved, this less burdensome option could allow for treatment at home or in medical facilities, potentially differentiating Leqembi from competitors like Eli Lilly's Kisunla (donanemab) and accelerating its adoption.
The FDA has granted fast-track status to the subcutaneous Leqembi application. However, the agency required Eisai and Biogen to submit a separate application for the subcutaneous formulation, even with the existing fast-track designation for the intravenous version. The partners have also filed to extend Leqembi's label to include a monthly intravenous maintenance dosing regimen.
Leqembi is currently approved for treating Alzheimer's patients with mild cognitive impairment or mild dementia in several regions, including the US, Japan, and China. However, recent regulatory decisions in the EU and Australia have been unfavorable, though the EU is re-examining the drug.
Biogen reported Leqembi sales of $67 million in the third quarter, including $39 million in the US, which fell short of expectations. The company anticipates that an expanded salesforce and the potential launch of monthly IV and subcutaneous doses could improve uptake. Biogen's CEO, Chris Viehbacher, suggested that extending the use of the subcutaneous injector into the induction phase of treatment could be a "game changer," with potential approval targeted for the first quarter of 2026.
