Key Points
- Donanemab is a new Alzheimer's drug that has been found to slow the progression of the disease.
- In the trials, donanemab appears to have slowed the pace of the disease by about a third.
- It is awaiting approval from a regulator.
An experimental new drug could offer hope and delay the severity of some symptoms of Alzheimer's, researchers say.
Donanemab — , a pharmaceutical manufacturer based in the United States — targets proteins in the brain and has been shown to slow down memory impairment in some participants.
It follows the trials of a , sold under the brand name Leqembi and recently approved in the US. It was considered the first viable treatment for a previously incurable illness.
Here's what we know about donanemab.
How does the donanemab work?
Donanemab has the best results if patients with Alzheimer's are treated as early as possible, ideally before they of the brain-wasting disease, researchers say.
The drug works by targeting and clearing protein pieces called amyloid plaques in the brain, which can contribute to inflammation and damage to brain cells, leading to cognitive decline.
A scientist examines scans of an Alzheimer's-affected brain. Source: AAP / David A.White/ BIOGEN /EPA
Referring to Lilly's data released on Monday, Dr Susan Kohlhaas, executive director of research and partnerships at Alzheimer's Research UK, said removing amyloid from the brain can alter the progression of the disease.
"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," she said.
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.
How effective is the new Alzheimer's drug?
Donanemab has been shown to slow the progression of memory and thinking problems by about a third.
But that rate doubles to 60 per cent if the drug is started when patients are only mildly impaired, according to trial data presented at the Alzheimer's Association International Conference in Amsterdam.
The complete analysis from the study involving more than 1,700 patients showed that results were less robust for older, later-stage patients and those with higher levels of a protein called tau that has been linked to Alzheimer's disease progression.
Anne White, executive vice president of Eli Lilly and president of Lilly Neuroscience, said the findings underscore that "earlier detection and diagnosis can really change the trajectory of this disease".
Donanemab, a drug produced by Eli Lilly, targets proteins in the brain and has been shown to slow down memory impairment in some participants. Source: AAP, AP / Darron Cummings
"At the end of the trial, the average patient had been without the drug for seven months, and yet they continued to benefit," White said.
She said the findings support the idea that donanemab can be stopped once amyloid is cleared from the brain.
Dr Liz Coulthard, associate professor in dementia neurology at the University of Bristol, said: "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."
For patients with high levels of the Alzheimer's-linked tau proteins, donanemab was shown to slow disease progression by about 17 per cent while the benefit was 35 per cent for those with low-to-intermediate tau levels.
What are the signs and symptoms of Alzheimer's?
Memory loss is one of the first signs of Alzheimer's.
The disease is the most common form of dementia, contributing to approximately two-thirds of cases in Australia.
Dementia is the second leading cause of death in Australia and the leading cause of death for women.
Around 400,000 to 500,000 Australians are currently living with dementia, and this number is predicted to reach almost 900,000 in the next 25 years.
Early signs can include memory loss, mood changes and disorders, increased confusion, withdrawal from social activities, inability to learn new things, and difficulty with language and reading.
Alzheimer's typically develops from a mild illness to a much more severe one.
At the end of a patient's life, they may be unable to communicate or control bodily functions.
Who can access donanemab?
Currently, no-one can access the new drug since it has not been approved by any regulator.
Lilly expects the US Food and Drug Administration to decide by the end of this year whether to approve donanemab.
The company said submissions to other global regulators are underway, and most will be completed by year-end.
Does donanemab have any side effects?
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.
Dr Liana Apostolova, professor in Alzheimer's disease research at Indiana University School of Medicine, said, "these side effects should not be taken lightly", but most cases were manageable by monitoring with magnetic resonance imaging (MRI) or stopping the drug.
Doctors will likely use "very stringent MRI safety screening while we treat these patients".
