Swedish research-based biopharma company BioArctic AB (STO:BIOA-B) and its partner Eisai Co Ltd (TYO:4523) announced on Monday that Australia's Therapeutic Goods Administration (TGA) has declined to approve lecanemab as a treatment for early-stage Alzheimer's disease in Australia.

The regulator rejected the reconsideration request after previously declining registration in October 2024.

Eisai proposed the same indication approved in Europe, allowing treatment for ApoE4 non-carriers and heterozygotes. The TGA only supported use in non-carriers, citing potential safety concerns for heterozygotes, and rejected Eisai's compromise of treatment in specialist centres. Eisai is now considering further options, including a review by the Administrative Review Tribunal.

Lecanemab is currently approved in 11 markets, including the United States, Japan, China and the UK, with regulatory filings submitted in the European Union and 17 other countries. The European Medicines Agency reaffirmed its positive opinion in February 2025, and the European Commission is proceeding with the approval process.

BioArctic and Eisai are preparing for joint commercialisation of lecanemab in the Nordic region.