Leqembi wins EU authorization for some Alzheimer’s patients, giving Biogen, Eisai a boost over Lilly

Title

EU Approves Leqembi for Select Early Alzheimer’s Patients, Giving Biogen and Eisai an Edge Over Lilly

Keywords

Leqembi
Lecanemab
Biogen
Eisai
Eli Lilly
Alzheimer’s disease
EU authorization
ApoE4 gene
Amyloid-related imaging abnormalities (ARIA)
Early Alzheimer’s treatment
Kisunla
EMA (European Medicines Agency)

Key Facts

Leqembi (lecanemab), developed by Biogen and Eisai, has secured European Union authorization as a treatment for adults with mild cognitive impairment or mild dementia due to Alzheimer’s disease, but only for patients with one or no copies of the ApoE4 gene1 2.
This marks Leqembi as the first Alzheimer’s treatment in Europe approved specifically for those in the early stages of the disease1.
Authorization follows a positive opinion by the EMA’s Committee for Medicinal Products for Human Use (CHMP) in November 2024, after initially being rejected for broader population use due to safety concerns1 2 4.
The restriction to patients with one or no copies of ApoE4 is due to the higher risk of amyloid-related imaging abnormalities (ARIA) in those with two copies of the gene1 2. ARIA encompasses brain swelling (ARIA-E) and microbleeds (ARIA-H), serious side effects associated with amyloid-targeting treatments like Leqembi.

- Clinical data showed a lower incidence of ARIA in the approved (restricted) group:
8.9% for ARIA-E and 12.9% for ARIA-H, versus higher rates in the broader population1.
- Leqembi will be dispensed under controlled-access programs. Patients must undergo MRI scans before treatment and at specified intervals to monitor for ARIA1 2.
- The EMA’s approval gives Biogen and Eisai a competitive advantage over Eli Lilly, whose rival drug Kisunla (donanemab) was recently rejected by EU regulators due to safety concerns and a risk-benefit profile that was not considered favorable5 8.
- Although Leqembi is not a cure, it has demonstrated efficacy in slowing the progression of cognitive decline in early Alzheimer’s, as shown in global trials4 6.
- Leqembi is already approved in the United States, Japan, China, South Korea, and other regions, but the European approval was delayed due to both efficacy concerns and regulatory review complexities7 10.
- The Alzheimer's Association and patient groups have welcomed the decision but continue to advocate for broader access as further data emerges4.

## Summary Table:
Leqembi vs Kisunla in EU Regulatory Process

| Drug | Company | EU Status (April 2025) | Target Patients | Main Restriction | Key Safety Concern |
|-------------|---------------|------------------------------------------|----------------------------------------|---------------------------------------|------------------------------|
| Leqembi | Biogen/Eisai | Approved for restricted population | Early Alzheimer’s with ≤1 ApoE4 copy | Excludes patients with 2 ApoE4 copies | Brain swelling, microbleeds (ARIA) |
| Kisunla | Eli Lilly | Rejected | Early Alzheimer’s, all genotypes | Not approved | Higher ARIA rates, fatal events |

Essential Takeaways

Leqembi is now the first EU-authorized treatment for early-stage Alzheimer’s, but only in those with specific genetic profiles that lower their risk of serious side effects.
Its regulatory success highlights a growing role for precision medicine in neurodegenerative diseases and underlines the need for safety monitoring in amyloid-targeting therapies.
Biogen and Eisai now have an advantage over Lilly in the European Alzheimer’s market, with broader uptake dependent on further real-world safety and efficacy data1 5.