Experimental drug may slow dementia onset for patients with rare genetic form of Alzheimer’s

An experimental treatment showed promising early results for reducing the risk of dementia related to Alzheimer’s for asymptomatic patients who are expected to develop the neurodegenerative disease.

Researchers followed a small group of 22 patients who had genetic mutations that cause the overproduction of amyloid in the brain.

One of the hallmarks of Alzheimer’s disease is when the protein amyloid sticks together and forms plaques in the brain.

According to the new findings published in the journal Lancet Neurology, when the 22 patients took an anti-amyloid drug called gantenerumab for eight years, they saw their risk of developing symptoms go from 100 per cent to about 50 per cent.

“Everyone in this study was destined to develop Alzheimer’s disease, and some of them haven’t yet,” said Randall Bateman, a professor of neurology at Washington University School of Medicine in the US and one of the study’s authors.

“In order to give [the patients] the best opportunity to stay cognitively normal, we have continued treatment with another anti-amyloid antibody in hopes they will never develop symptoms at all,” Bateman added.

The findings suggest that early treatment could delay the onset of Alzheimer’s symptoms.

Years of treatment might be necessary for prevention

The cognitive benefits were shown among the patients who received the treatment for eight years while others, who were treated for only two to three years, didn’t show a noticeable improvement. 

This suggests that preventive therapy may be required for years before someone develops symptoms to be effective. 

Charles Marshall, a professor of clinical neurology at the Queen Mary University of London in the UK, qualified the study’s findings as “very exciting” in a statement but highlighted two limitations of the study. 

“The first is that it was a secondary evaluation of a relatively small number of people who were treated for a long time, and therefore the results are not as certain as they would have been if they were the main trial result,” he said.  

“The other limitation is that gantenerumab is not nearly as effective as some of the other amyloid reducing treatments that are now available, suggesting that we may be able to do even better than these results suggest,” he added.

Gantenerumab was discontinued in 2022 because it failed to slow symptoms of the more common forms of Alzheimer’s disease in a trial with over 1,900 participants.

More research is needed to evaluate the potential of anti-amyloid drugs, the best length of treatment, and their effects on the non-genetic forms of the disease, as well as potential side effects.

Anti-amyloid drugs have, for instance, been linked to side effects such as abnormalities on brain scans and localised swelling. While most of these side effects resolve on their own, some can become serious.

In the trial, two participants had to stop taking the drug due to side effects, but there were no life-threatening adverse effects, researchers said.