Biogen (NASDAQ:BIIB) and Eisai have cleared a significant regulatory hurdle as the U.S. Food and Drug Administration (FDA) accepted their supplemental Biologics License Application for a subcutaneous version of the Alzheimer’s treatment Leqembi.
The FDA granted the application Priority Review, a designation that fast-tracks the evaluation process for drugs that offer significant improvements in safety or effectiveness.
The agency has set a PDUFA action date for May 24, 2026.
The application seeks approval for a 500 mg weekly starting dose delivered via a subcutaneous autoinjector, branded as LEQEMBI IQLIK.
While a lower-dose maintenance version (360 mg) was approved in August 2025 for patients who had already completed 18 months of intravenous (IV) therapy, this new filing would allow patients to bypass the infusion clinic entirely, starting their treatment at home.
Data from Phase 3 sub-studies presented by the companies showed that the weekly 500 mg injection achieved drug exposure levels equivalent to the current standard of bi-weekly IV infusions.
Crucially, the clinical and biomarker benefits remained consistent across both delivery methods.
The shift to an autoinjector could dramatically alter the market landscape for Alzheimer's therapies.
By enabling at-home initiation, the treatment reduces the burden on overstretched infusion centers and simplifies the logistics for patients and caregivers.
Safety data from the trial was a highlight, with systemic injection reactions occurring in less than 2% of participants, a profile comparable to the existing IV administration.
Leqembi is currently approved in 53 countries, including major markets like Japan, China, and the European Union.
Eisai continues to lead the global development and regulatory efforts, while Biogen co-commercializes the product.