EMA experts will look again at Leqembi's safety data

It seems Eisai and Biogen have another hurdle to jump over in their bid to get EU approval for their Alzheimer's disease therapy Leqembi.

In the latest development, the European Commission has asked the EMA's human medicines committee, the CHMP, to take a look at up-to-date safety data on Leqembi (lecanemab) at its next meeting in February.

The CHMP recommended against approval of Leqembi in July 2024, a shock decision that came after regulators in the US, China, and Japan cleared use of the drug to treat mild Alzheimer's, saying that the risk of serious side effects with the drug outweighed its modest efficacy in delaying cognitive decline.

The CHMP changed its mind the following November after re-examining its initial opinion, but only for a subgroup of patients who have only one or no copy of ApoE4, a form of the gene for the protein apolipoprotein E, which is a risk factor for Alzheimer's.

Patients with only one or no copy of ApoE4 are less likely to experience side effects like the brain swelling and bleeding associated with amyloid-targeting drugs like Leqembi than people with two ApoE4 copies.

Now, the CHMP has been asked to consider safety data generated since it arrived at its latest opinion and gauge "whether this may require an update of the opinion, and to consider whether the wording of the risk minimisation measures in the opinion is clear enough to ensure correct implementation."

The potential implications of the decision - either positive or negative - are hard to assess at the moment, but it does represent a delay to Leqembi's EU approval, which was expected within the usual 67-day timeframe after the CHMP's published opinion in mid-November. That already makes the EU verdict around 10 days overdue.

In a statement, Eisai and Biogen said they believe the safety profile of Leqembi has been reinforced by its use in clinical practice in the US and other countries where it has already been introduced.

"We believe that the EC's requests can be addressed with existing information and will be evaluated by the CHMP because of the clear and sufficient information available," they said.

"We will continue to work closely with the authorities toward approval in the EU."

The EU development comes shortly after Eisai and Biogen were given approval for a new once-monthly intravenous maintenance dose of Leqembi in the US, after a biweekly IV initial induction course, that would reduce the number of visits needed to an infusion clinic.

The two companies are also hoping to get the go-ahead later this year for a new subcutaneous autoinjector formulation that could be administered at home.

Photo by Guillaume Périgois on Unsplash