Eisai, a partner of BioArctic AB (NASDAQ Stockholm: BIOA B), announced that Japan has approved a subcutaneous autoinjector formulation of Leqembi, known as Leqembi Pen, as a new route of administration for the treatment of early Alzheimer's disease.

The Leqembi Pen allows patients or care partners to self-administer treatment at home via two injections totaling 500 mg, given once weekly. Each injection takes approximately 15 seconds. The approval adds to the existing intravenous (IV) formulation, which requires administration every two weeks in a hospital setting.

Japan is the third country globally to approve the subcutaneous formulation of Leqembi. The approval is based on integrated data and modeling from the 18-month Phase 3 Clarity AD study and subcutaneous administration sub-studies from its long-term extension.

The once-weekly 500 mg subcutaneous dose demonstrated similar drug exposure to IV administration given every two weeks. The overall safety profile was described as generally similar between the two formulations, though systemic injection or infusion-related reactions occurred less frequently with subcutaneous administration at 1.4%, compared with the IV formulation. Monitoring for amyloid-related imaging abnormalities (ARIA) via brain MRI is required for both routes of administration.