BioArctic AB (publ) and its partner Eisai presented new data on lecanemab (brand name: Leqembi) at the 2024 International Conference on Alzheimer's and Parkinson's Diseases and related neurological disorders (AD/PD), held in Lisbon, Portugal and virtually, March 5-9. BioArctic's founder, Professor Lars Lannfelt, presented data on the binding properties of the anti-amyloid-beta (Aß) antibody lecanemab and other anti Aß antibodies. Lecanemab was designed to preferentially bind soluble (protofibrils), as well as insoluble Aß aggregates (fibrils), to reduce both Aß protofibrils and Aß plaques in the brain. The difference in binding to CAA was presented, with lecanemab having lower binding to CAA than most other antibodies.

This could explain the difference in the adverse event ARIA seen between different antibodies, with lecanemab showing relatively low incidence of ARIA. In another presentation Professor Christopher van Dyke presented extended efficacy results from the Phase 3 Clarity AD open label extension study of lecanemab in Alzheimer's disease up to 30 months, showing continued benefit with lecanemab treatment. Professor van Dyke also highlighted data from the tau sub-study of Clarity AD, which showed that all cohorts of the tau population benefitted from treatment with lecanemab.

Data from the low tau population, representing earlier stages of the disease, indicated that intervening in early stages of disease may be particularly impactful in stabilizing the disease process. Lecanemab is the result of a long-standing collaboration between BioArctic and Eisai, and the anti Aß protofibril antibody was originally developed by BioArctic based on the work of Professor Lars Lannfelt and his discovery of the Arctic mutation in Alzheimer's disease. Eisai serves as the lead of lecanemab development and regulatory submissions globally with both Eisai and Biogen co-commercializing and co-promoting the product and Eisai having final decision-making authority.

BioArctic has the right to commercialize lecanemab in the Nordic region, pending European approval, and currently Eisai and BioArctic are preparing for commercialization in the region.