Eisai and Biogen’s Supplemental Biologics License Application (sBLA) for Leqembi (lecanemab) subcutaneous autoinjector (SC-AI) has been accepted by the US FDA under Priority Review to treat early Alzheimer’s disease.
The sBLA was supported by results from the phase 3 Clarity AD study programme, including its open-label extension (OLE). These results showed that once-weekly administration of Leqembi SC-AI gave equivalent drug exposure to the currently-approved intravenous (IV) administration once every two weeks. It also showed similar clinical and biomarker benefits and demonstrated a safety profile consistent with IV administration.
If approved, Leqembi SC-AI could be administered subcutaneously once a week, rather than through the currently approved IV administration once every two weeks. The subcutaneous injection of Leqembi takes only 15 seconds and can be completed at home, potentially giving patients and carers the option to complete both initial and maintenance treatment without the need for hospital visits. It could also reduce the financial burden on healthcare systems caused by IV treatment.
Alzheimer’s disease is a neurodegenerative disorder characterised by progressively severe memory loss and loss of motor function. Leqembi has a dual mechanism of action, targeting both protofibrils and amyloid plaque in the brain in order to slow the disease’s progress.
Leqembi is designed to treat the early stage of Alzheimer’s disease, also known as mild dementia or mild cognitive impairment (MCI). This was the patient group evaluated by the Clarity AD programme. Treatment with Leqembi is designed to slow the development of Alzheimer’s and delay worsening of symptoms.
Leqembi is currently approved in 53 countries and regions, and is under regulatory review in a further seven. Additionally, the FDA approved Leqembi Iqlik as a weekly subcutaneous maintenance treatment following 18 months of IV treatment in August 2025.