EMA rejects Eisai-Biogen Alzheimer's drug

The EMA's medicines committee (CHMP) has advised against granting marketing authorization for the Alzheimer's treatment Leqembi, developed in partnership by Eisai and Biogen. The committee raised concerns over the drug's safety profile, noting that its potential benefits in delaying cognitive decline do not outweigh the risks of serious side effects. Specifically, the committee highlighted the frequent occurrence of amyloid-related imaging abnormalities (ARIA), which involve swelling and possible bleeding in the brains of patients treated with Leqembi.

Another significant concern raised by the CHMP was the heightened risk of ARIA in individuals carrying a specific variant of the apolipoprotein E gene, known as ApoE4. People with two copies of the ApoE4 gene are particularly vulnerable to developing Alzheimer's disease and, consequently, would be likely candidates for Leqembi treatment. This gene-specific risk further complicated the committee's evaluation of the drug's overall safety and efficacy.

Leqembi received initial approval in the United States in January 2023 for treating mild cognitive impairment due to early-stage Alzheimer's disease under the FDA's accelerated approval program. By July 2023, the FDA upgraded its status to full approval, albeit with a black box warning to highlight the ARIA-related safety issues. Besides the U.S., Leqembi has also been approved in several other countries, including Japan, China, South Korea, Hong Kong, and Israel.

In response to the EMA's decision, Eisai expressed significant disappointment. The company announced its intention to seek a re-examination of the CHMP's opinion. Eisai plans to collaborate with the relevant authorities to explore the possibility of bringing Leqembi to the European market despite the current setback.