EU regulators block new Alzheimer’s drug citing potentially fatal side effects

Alzheimer’s patients in the European Union will have to keep waiting for new treatments after regulators blocked a drug that’s already been approved in the United States and the United Kingdom.

The drug donanemab, sold by Eli Lilly as Kisunla, is a monoclonal antibody that slowed the progression of Alzheimer’s for people with early stages of the disease in a key clinical trial. It’s taken via a once-monthly infusion.

It would have been only the second new Alzheimer’s drug green-lit by the European Medicines Agency (EMA), the EU’s drugs regulator, in two decades.

Alzheimer’s is the most common form of dementia, which affects an estimated 7 million people in Europe, according to the European Brain Council.

But an EMA expert committee said the medicine should not be approved due to concerns about potentially deadly side effects for certain patients.

“The benefits of Kisunla were not large enough to outweigh the risks of potentially fatal events,” the agency said, citing the risk of amyloid‑related imaging abnormalities (ARIA), a common side effect that can cause swelling and bleeding in the brain.

Kisunla was developed for patients with amyloid beta plaques, which are build-ups of protein in the brain and characteristic of Alzheimer’s. 

The drug works by attaching to the amyloid beta, reducing the plaque build-up and delaying the disease progression.

In a late-stage clinical trial, Kisunla slowed the development of dementia symptoms by up to 35 per cent at 18 months. But three people with serious ARIA died, including two who were carriers of a certain type of gene that raises the risk of Alzheimer’s.

Eli Lilly had suggested that Kisunla be offered only to patients who do not have the gene – but that wasn’t enough for the EMA.

Angela Bradshaw, research director at Alzheimer Europe, said the dementia community has been excited about the new medicine, but cautioned that it is not a “miracle drug” or “cure”.

“They work much better the earlier people receive these medicines,” she told Euronews Health, “but also they do have some safety concerns”.

Alzheimer Europe, which is an umbrella group for Alzheimer’s groups in three dozen countries, said patient safety is important but that a controlled access programme with safety monitoring could have enabled Europeans with early-stage Alzheimer’s to access the new treatment while keeping it away from people at high risk of serious side effects.

The European Commission, which is the EU’s executive body, has 67 days to adopt the EMA’s recommendation. That will be the official, legally binding decision.

Taking a second look

It is not necessarily the end of the road for Kisunla.

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Last year, the EMA reversed its initial refusal of Leqembi, another Alzheimer’s drug that also carries a risk of ARIA for people with the high-risk gene.

After initially voting against Leqembi for a broad set of Alzheimer’s patients, it recommended in November that the drug be offered to people who have only one or no copies of the gene. 

The European Commission is expected to issue its marketing authorisation.

Eli Lilly said it will ask the EMA to reconsider its decision on Kisunla.

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“We hope that through the re-examination process, we will be able to continue our discussions with the agency to bring donanemab to the millions of people across Europe suffering from this relentless, fatal disease,” Ilya Yuffa, executive vice president and president of Lilly International, said in a statement.

The drug has already been approved in the US, Japan, China, and the UK. But it is not currently being offered to UK patients through the National Health Service (NHS) after its drug pricing watchdog said the medicine was not cost-effective enough.

Bradshaw said the high cost of medicines like Kisunla and Leqembi could pose challenges for patients given they are expected to cost about €25,000 per year, and require regular infusions, brain scans, genetic testing, and side effect monitoring.

“While the drug itself is expensive, all the stuff around it too is also incredibly expensive, because these aren’t easy medicines to take,” Bradshaw said.

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