On 15 April 2025, the European Commission granted EU authorisation for lecanemab to treat mild cognitive impairment (MCI) and mild dementia due to Alzheimer’s disease (collectively referred to as early Alzheimer’s disease) in adults who have only one or no copy of the ApoE4 gene and who have confirmed amyloid beta plaques in the brain. Marketed under the brand name Leqembi®, it is the first medicine of its kind to be authorised in the EU.

This approval follows the positive scientific assessment of the European Medicines Agency (EMA), which concluded that the benefits of this medicine outweighed the risks for this specific population, as long as risk minimisation measures are applied. 

Eisai, in collaboration with national and regional healthcare authorities, has established the controlled-access programmes required under the EU marketing authorisation. With these programmes in place, Austria and Germany have become the first EU countries to make the therapy available, ensuring compliance with EU regulatory requirements.

This is also another important step in the use of PET amyloid imaging in research and clinical routine. In the pivotal clinical trials the effect of lecanemab on amyloid beta plaque levels in the brain was evaluated using PET imaging visual read and quantification and demonstrated a statistically change from baseline for lecanemab compared to placebo. Confirming amyloid beta plaques in the brain prior to commencing therapy is an important eligibility criteria and will further drive the use and utility of PET amyloid imaging in clinical practice.

About Leqembi® (lecanemab): It is a humanised immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). It was developed through a collaboration between BioArctic and Eisai, with Eisai leading its global development, regulatory filings, and commercialisation alongside co-promotion by Biogen.

The European Commission’s authorisation was primarily based on Phase 3 data from Eisai’s global Clarity AD clinical trial, in which it met its primary endpoint and all key secondary endpoints with statistically significant results.

Interesting reads:

• European Commission announcement:https://ec.europa.eu/newsroom/sante/items/879055/en 
• EMA approval: https://www.ema.europa.eu/en/medicines/human/EPAR/leqembi
• EISAI press release: https://www.eisai.com/news/2025/news202557.html