The European Union’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 impact on slowing cognitive decline.
The decision, released on Friday, is a blow to the companies as the drug faces slow take-up in the United States. Biogen’s shares fell 5% to $216.28 in early US trading.
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 U.S., 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, seven million people are living with the disease, and that figure is expected to double by 2050, according to non-profit 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 hospitalizations 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 scrutinize new drugs.
The recommendation must be formally 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.
One Alzheimer’s expert said the decision reflected the complex considerations that had to be taken into account on the drug, which costs roughly $26,500 per year in the U.S..
Truist Research analyst Srikripa Devarakonda had expected sales of $2.4 billion in Europe by 2035 for Biogen, accounting for a 50-50 split with Eisai.
The U.S. approved the drug last year and requires a warning against brain-related side effects. A rival from Eli Lilly gained US approval this year.
“The decision creates pressure on EMA to create clear guidance on what clinically meaningful benefit in syndromal Alzheimer’s disease is,” said Ivan Koychev, principal clinical investigator at the United Kingdom Dementia Platform.
