The US FDA has accepted a supplemental Biologics License Application (sBLA) from Eisai and Biogen for a weekly subcutaneous starting dose of Leqembi Iqlik (lecanemab-irmb), granting the submission Priority Review with a Prescription Drug User Fee Act (PDUFA) target action date of May 24, 2026.

The filing seeks approval of a 500 mg once-weekly subcutaneous (SC) regimen – delivered as two 250 mg injections using an autoinjector device – as an alternative to the current bi-weekly intravenous (IV) initiation dosing. If approved, this would allow patients with early Alzheimer’s disease to begin treatment at home and transition between SC and IV regimens based on clinical need. The autoinjector dose takes roughly 15 seconds per injection.

Clinical context:

Leqembi is a humanized monoclonal antibody that targets soluble amyloid beta protofibrils and plaques in the brain, a hallmark of Alzheimer’s disease. It is approved in the US for treatment of mild cognitive impairment (MCI) due to Alzheimer’s and mild Alzheimer’s dementia with confirmed amyloid beta pathology.

The antibody received an accelerated approval in the US in January 2023 for patients with mild cognitive impairment or mild dementia stage of Alzheimer’s on a bi-weekly IV schedule, converted to full approval in July that year. A maintenance dose administered intravenously once every four weeks was approved in January 2025, for patients treated bi-weekly for 18 months, while a subcutaneous version of that maintenance dose was approved in August 2025.