A drug that has been shown to stall the symptoms of Alzheimer’s is being hailed as a turning point in treatment of the distressing disease.

The experimental drug donanemab changed patients’ lives by slowing progression of memory and thinking problems by about a third.

That rate doubled to 60 per cent if the drug, from company Eli Lilly, was started early before dementia patients were badly impaired.

The results of trial data were presented overnight Monday (AEST) at the Alzheimer’s Association International Conference in Amsterdam.

The findings underscored that “earlier detection and diagnosis can really change the trajectory of this disease,” said Anne White, Lilly’s president of neuroscience.

It is being hailed as a major breakthrough in combatting the disease which is the most common form of dementia and has no cure.

Lilly expects the US Food and Drug Administration to decide by the end of this year whether to approve donanemab.

It said submissions to other global regulators are underway and most would be completed by year end.

The study involved more than 1700 patients, including 16 Australians in Victoria and NSW.

It found that the results were less robust for older, later-stage patients as well as those with higher levels of a protein called tau that has been linked to Alzheimer’s disease progression.

How it works

Donanemab, an intravenous antibody, is designed to remove deposits of a protein called ‘beta amyloid’ from the brains of Alzheimer’s patients.

“These results provide further confirmation that removing amyloid from the brain can change the course of Alzheimer’s, and may help people affected by this devastating disease if they’re treated at the right time,” said Dr Susan Kohlhaas, executive director of research and partnerships at Alzheimer’s Research UK.

This works in the same way as the recent drug Leqembi, from Eisai and Biogen, which was the first found to slow the disease late last year.

Lilly’s study showed that brain swelling, a known side effect of amyloid-clearing antibodies, occurred in more than 40 per cent of patients with a genetic predisposition to develop Alzheimer’s.

The company had previously reported that 24 per cent of the overall donanemab treatment group had brain swelling.

Brain bleeding occurred in 31 per cent of the donanemab group and about 14 per cent of the placebo group.

The deaths of three trial patients were linked to the treatment, researchers reported.

“These side effects should not be taken lightly” but most cases were manageable by monitoring with magnetic resonance imaging or stopping the drug, said study investigator Dr Liana Apostolova, professor in Alzheimer’s Disease research at Indiana University School of Medicine.

Doctors are likely to use “very stringent MRI safety screening while we treat these patients”, she said.

Lilly said donanemab’s treatment effect continued to increase relative to placebo over the course of the 18-month trial, even for participants who had been taken off the drug after their levels of amyloid deposits fell significantly.

“At the end of the trial, the average patient had been without drug for seven months and yet they continued to benefit,” Dr White said.

She said the findings supported the idea that donanemab could be stopped once amyloid is cleared from the brain.

“Some patients did not worsen significantly during the trial and on average progression of disease was slowed 4.4-7.5 months over 18 months,” said Dr Liz Coulthard, associate professor in dementia neurology at the University of Bristol.

The full study results were also published in JAMA.

“Whether the harms of these drugs are balanced by their modest clinical benefits will ultimately require more data,” an editorial in JAMA alongside the study said.