Swedish research-based biopharma company BioArctic AB (STO:BIOA-B) and its Japanese partner Eisai Co Ltd (TYO:4523) announced on Tuesday that the first patient has begun treatment with Leqembi (lecanemab) at a private clinic in Finland.

The therapy is co-promoted by the two partners in the Nordic region.

Leqembi received European Commission approval in April 2025 as the first therapy targeting the underlying causes of Alzheimer's disease, indicated for adults with mild cognitive impairment or mild dementia due to Alzheimer's who are ApoE ε4 non-carriers or heterozygotes with confirmed amyloid pathology. A controlled access programme is now operational in Finland, enabling private clinics such as Terveystalo Ruoholahti to administer the treatment while public healthcare inclusion is under assessment.

The antibody, originally developed by BioArctic, targets both amyloid-beta protofibrils and amyloid plaques, addressing neurodegeneration pathways associated with tau tangles. Eisai leads clinical development, market approvals, and commercialisation, while BioArctic retains co-commercialisation rights in the Nordics.

Leqembi is approved in 50 countries, including the United States, Japan, China, and the EU, and is under review in 10 additional countries. Maintenance dosing via IV or subcutaneous injection is approved or under review in multiple regions.