New drug could stop slide into early dementia

Study focused on small group of people who had inherited genetic mutations that meant they were likely to develop Alzheimer’s in their 30s to 50s.

New drug aimed at preventing early Alzheimer’s disease could stop slide into early dementia.

An experimental drug appears to reduce the risk of Alzheimer’s disease in people destined to develop the condition in middle age, raising hopes that early treatment could be effective.

The study involved 73 people with rare inherited genetic mutations that cause the overproduction of a toxic protein, amyloid, in the brain, meaning they were all but guaranteed to develop Alzheimer’s in their thirties to fifties.

For 22 patients who had no cognitive problems at the outset of the study and who received the drug the longest – for an average of eight years – the treatment appeared to cut the risk of developing symptoms by about half.

The results will boost hopes that using similar treatments to target the much more common form of Alzheimer’s that appears when people reach their sixties, seventies and eighties might also be effective.

The study, published in the Lancet Neurology journal, appeared to bolster the “amyloid hypothesis”, which posits that sticky plaques of amyloid build up in the brain and play an important role in advancing the disease.

Several trials looked at whether using antibody drugs to mop up amyloid could reduce or reverse the progress of Alzheimer’s. So far they had only shown a modest slowdown in the worsening of symptoms, possibly because the participants in these trials already displayed symptoms.

By contrast, the most recent trial looked at whether an anti-amyloid therapy, gantenerumab, could prevent the development of dementia before outward signs had appeared.

“Everyone in this study was destined to develop Alzheimer’s disease and some of them haven’t yet,” said Professor Randall Bateman of Washington University, in St Louis, Missouri. “We don’t yet know how long they will remain symptom-free, maybe a few years or maybe decades. What we do know is that it’s possible at least to delay the onset of the symptoms of Alzheimer’s disease and give people more years of healthy life.”

Professor Tara Spires-Jones of the University of Edinburgh and the UK Dementia Research Institute, who was not involved with the study, said the results were “important scientifically as evidence that amyloid-lowering drugs may potentially be able to delay symptom onset”.

Gantenerumab is no longer made by Roche, the company that developed it, because it did not slow symptoms of the more common non-genetic forms of Alzheimer’s disease in a trial with more than 1900 participants. However, other anti-amyloid drugs are being developed.

A scan showing normal brain tissue.

And a brain affected by Alzheimer’s.

Professor Charles Marshall of Queen Mary University of London, who was also not involved in the study, said: “It seems from these results that if treated for long enough with a drug that reduces amyloid beta protein in the brain, we can delay the development of symptoms in those who will go on to develop Alzheimer’s disease, and this is very exciting.”

He cautioned, however, that the trial involved only a small number of people, adding: “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.”

Marshall said the research would give “tremendous hope to the families that have these rare genetic mutations, and these results suggest that in years to come we may have preventive treatments to offer them”.

The Times