Swedish biopharmaceutical company BioArctic AB (STO: BIOA-B) on Wednesday shared that its partner Eisai Co Ltd (TYO: 4523) has received Japanese approval for the subcutaneous autoinjector formulation of Leqembi for early Alzheimer's disease, making Japan the third country to approve the formulation.

The Leqembi Pen is designed to allow once-weekly self-administration at home, using two injections totalling 500 mg, complementing the existing intravenous formulation given every two weeks in hospital. With each injection taking about 15 seconds, at-home dosing is expected to reduce clinic visits and ease treatment burden for patients and care partners.

Eisai said the subcutaneous option may lower barriers to initiating and continuing treatment and reduce healthcare resources associated with IV infusions, including nurse monitoring and infusion capacity. Routine monitoring for amyloid-related imaging abnormalities via MRI is still required before treatment and at specified intervals.

Approval was based on integrated data and modelling from the 18-month Phase 3 Clarity AD core study and multiple subcutaneous sub-studies in its long-term extension, which showed similar exposure and expected efficacy to IV dosing. The safety profile was generally comparable, with systemic injection or infusion reactions occurring less frequently with subcutaneous administration (1.4%).

Eisai is responsible for drug development, regulatory submissions and global commercialisation or Leqembi, while BioArctic holds commercial rights in the Nordic region and receives milestone payments and royalties on global sales.