EU Regulator Rejects Eisai and Biogen’s Alzheimer’s Drug Leqembi

(Reuters) --The European Union's drugs regulator has rejected Eisai and Biogen's Leqembi treatment for early Alzheimer's disease, citing the risk of serious brain swelling as a significant disadvantage. The decision is a blow to the companies as the drug faces slow take-up in the U.S. and underscores the complexities of a new class of drugs that have benefited early stage patients but could cause rare and serious side effects. Biogen's shares fell about 7% in U.S. trading after the rejection, while rival Eli Lilly, which makes a similar drug, slipped 1%. Eisai and Biogen said they will seek reexamination of the recommendation, but did not disclose what information they would provide the regulator.

Leqembi, also known as lecanemab, is approved in the U.S., China, Hong Kong, Israel, Japan, and South Korea. In clinical trials, the drug slowed cognitive decline by 27% in early Alzheimer's patients, compared with a placebo. In Europe, 7 million people live with the disease, according to nonprofit Alzheimer's Europe. The EU regulator 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 showed only a small absolute difference in patients who received lecanemab versus a placebo, cases of ARIA, a type of brain swelling and bleeding seen in its clinical trials that led to hospitalizations of some patients, and elevated risk of brain swelling and bleeding in people with two copies of the APOE4 gene, which is also associated with a higher risk of Alzheimer's.