On 13 July, Eisai and Biogen announced that the US Food and Drug Administration (FDA) has approved a supplemental Biologics License Application (sBLA) for a once-weekly subcutaneous (SC) initiation dose of lecanemab for the treatment of early Alzheimer’s disease (AD). The approval marks the first subcutaneous initiation option for an anti-amyloid therapy, allowing eligible patients to begin treatment at home using an autoinjector rather than requiring intravenous (IV) administration.
Lecanemab is administered using an autoinjector, providing a convenient alternative to IV administration from the start of treatment. In August 2025, the FDA approved the subcutaneous autoinjector formulation of lecanemab for maintenance dosing following an 18-month IV induction period. This latest approval expands its use to treatment initiation, with the new regimen expected to be available in the US in late August 2026 through specialty pharmacies.
For initiation, the approved regimen is 500 mg given once weekly as two 250 mg injections, each delivered in approximately 15 seconds. For maintenance, lecanemab may be administered at 360 mg once weekly after 18 months of IV or SC treatment. Throughout the treatment course, patients may receive lecanemab either as an IV infusion or as a subcutaneous injection with lecanemab and may switch between administration routes as clinically appropriate, providing greater flexibility and convenience. The safety profile of the SC starting dose regimen is consistent with the broader lecanemab programme. The most common adverse events include headache, injection site reactions and amyloid-related imaging abnormalities (ARIA).
https://investors.biogen.com/news-releases/news-release-details/fda-approves-leqembi-iqlikr-lecanemab-irmb-subcutaneous
