EU regulator rejects Alzheimer’s drug from Eisai and Biogen

The EU’s drugs regulator has rejected Eisai and Biogen’s Leqembi treatment for early Alzheimer’s disease, saying the risk of serious brain swelling did not outweigh its small effect on slowing cognitive decline.

The decision is a blow to the companies as the drug faces slow take-up in the US even as it underscores the complexities tied to a new class of drugs that have benefited early-stage patients, but could cause rare and serious side effects.

Biogen’s shares fell 5% in US trading after the rejection while rival Eli Lilly, which makes a similar drug, slipped 1%.

Eisai and Biogen said they will seek re-examination of the recommendation, but did not disclose what information they would provide the regulator.

The therapy is approved in the US, China, Hong Kong, Israel, Japan and South Korea, and would have been Europe’s first drug to treat the neurodegenerative condition rather than its symptoms. Its chemical name is lecanemab.

The infusion, given twice a month, removes sticky clumps of protein amyloid beta from the brain, believed to be a hallmark of Alzheimer’s disease.

In clinical trials, the drug slowed cognitive decline by 27% in early Alzheimer’s patients, compared with a placebo.

In Europe, 7-million people are living with the disease, and that figure is expected to double by 2050, according to nonprofit Alzheimer’s Europe, which was disappointed with the decision.

The EU regulator said it relied on the analysis by the agency’s committee for medicinal products for human use, and cited three primary concerns.

An 18-point scale used in the trial to measure functions such as memory and problem-solving showed only a small absolute difference in patients who received lecanemab versus a placebo, it said.

It also pointed to cases of ARIA, a type of brain swelling and bleeding, seen in its clinical trials that led to hospitalisation of some patients.

“The seriousness of this side effect should be considered in the context of the small effect seen with the medicine,” the regulator said.

The committee noted elevated risk of brain swelling and bleeding in people who have two copies of the APOE4 gene, which is also associated with a higher risk of Alzheimer’s.

Reuters reported last year, citing researchers, that the drug was unlikely to be used widely even if approved in Europe, where cost-conscious countries rigorously scrutinise new drugs.

Leqembi’s US launch has so far been lacklustre, with bottlenecks due to its requirements such as additional diagnostic tests, twice-monthly infusions and regular brain scans.

One Alzheimer’s expert said the decision reflected the complex considerations around the drug, which costs about $26,500 a year in the US.

The requirements “lead to the question if limited resources (not just money but also trained staff) could produce better results for patients if used elsewhere,” said Sebastian Walsh, National Institute for Health and Care Research doctoral fellow, University of Cambridge.

The decision puts pressure on European regulators to create clear guidance on what is the clinically meaningful benefit for treating Alzheimer’s disease, said Ivan Koychev, principal clinical investigator at the Dementia Platform UK.

The recommendation must be backed by the European Commission, which usually follows the regulator’s decision automatically.

The drug has been under review in the region since January 2023. The US approved it last year and requires a warning against brain-related side effects.

A rival from Lilly gained US approval this year. Lilly’s application is being reviewed by European regulators.

Reuters