Eisai and Biogen Receive Final Marketing Authorization from the European Commission for Alzheimer's Drug 'Leqembi'
Official Entry into the European Market and Regulatory History
The European Commission (EC) has granted final approval for Leqembi (lecanemab), Eisai (4523.T) and Biogen's (BIIB) Alzheimer's disease treatment, on April 15, 2025. This follows the initial rejection by the European Medicines Agency (EMA) advisory committee in July 2024, with approval secured by narrowing the target population to individuals who do not carry the ApoE ε4 gene and those who are heterozygous. This marks a significant achievement, following approvals in the United States (July 2023) and Japan (September 2023), securing access to the world's top three pharmaceutical markets.
Clinical Efficacy and Rationale for Genetic Restriction
In the Phase 3 Clarity AD trial, Leqembi delayed cognitive decline by 27%; however, the incidence of amyloid-related imaging abnormalities (ARIA) was higher in patients with the ApoE ε4 homozygous genotype, leading to their exclusion from the eligible patient population. This was a precise, patient-centric decision by regulatory authorities to focus benefits on a safer patient population, representing approximately 60-70% of early Alzheimer's patients, thereby ensuring treatment safety. Consequently, pre-treatment genetic testing has become a standard requirement in clinical practice.
Global Competition and Product Diversification
With this approval, a full-fledged market competition is expected with Kisunla (donanemab), the competing drug from Eli Lilly (LLY). Kisunla is scheduled to receive European approval in September 2025 and is rapidly gaining ground. However, Eisai is accelerating the development of a subcutaneous (SC) formulation of Leqembi to improve ease of administration. The introduction of the SC formulation is expected to significantly improve the frequency of patient visits to the hospital, potentially creating a barrier to entry for competing drugs.
Reimbursement Challenges and Market Penetration
Despite obtaining marketing authorization, delays in cost-effectiveness evaluations and reimbursement approvals by national health authorities could hinder short-term revenue growth. While supply will begin in countries such as Germany, securing favorable pricing agreements in each country is a top priority to gain a foothold in the overall Alzheimer's treatment market, which is expected to grow rapidly to approximately $15 billion by 2030.
Partnership and Milestone Payments
This approval is being managed under the 50/50 global co-commercialization agreement between Eisai and Biogen, solidifying their long-term growth engine. Furthermore, BioArctic (BIOA B.ST), the originator of Leqembi, will receive a regulatory milestone payment of €20 million (approximately $21.6 million) from Eisai upon this marketing authorization. This is a prime example of the direct financial benefits resulting from an ideal collaborative development partnership between an innovative biotech company and a large pharmaceutical company.
The final European approval of Leqembi marks a significant milestone for Eisai and Biogen, securing access to the European market following approvals in the United States and Japan, and positioning them to capture a significant share of the global Alzheimer's disease treatment market, projected to reach $15 billion by 2030. With Eli Lilly's Kisunla expected to receive European approval in September 2025, the speed at which Leqembi can achieve market penetration through successful pricing negotiations and reimbursement approvals with national health authorities will be a critical factor in driving short-term revenue growth. From a research perspective, further real-world data is needed to assess whether excluding patients with the ApoE ε4 homozygous genotype from treatment will significantly reduce the incidence of ARIA in clinical practice. In the long term, the transition to a more convenient subcutaneous (SC) formulation and the expansion of ApoE genetic testing infrastructure prior to treatment are expected to contribute to increased market share for both companies and additional milestone payments for BioArctic.
Source: EMA (ema)