Drug currently in trial appears to slow onset of disease for early stage patients.
An experimental Alzheimer's drug has given hope to early-stage patients and showed it could slow — or even halt — mental decline, the results of a preliminary trial showed on Wednesday.
The drug, aducanumab, is the only latest antibody to show progress in an early, Phase I drug trial, experts have said. Scientists are cautiously optimistic as other drugs introduced in the past ended up failing during large trials.
"Although potentially this is an exciting story, it is important to temper any excitement with considerable caution," said Robert Howard, a professor of old age psychiatry at University College London.
"It would be premature to conclude that this is likely to represent an effective treatment for Alzheimer's disease."
Researchers in the United States and Switzerland tested the drug developed by biotech firm Biogen, on 165 people in their early stage of the disease for a period of one year.
Some were given a monthly injection of the antibody, and others a placebo or dummy drug.
The researchers presented their findings in the journal Nature which showed that in the brains of those given the treatment, there was an "almost complete clearance" of so-called amyloid plaques, the researchers reported.
Amyloids are sticky proteins that clump together in deposits — one of the mechanisms suspected of causing Alzheimer's.
"The effect of the antibody is very impressive," said Roger Nitsch, a professor at the University of Zurich's Institute for Regenerative Medicine, who co-authored the study.
'Now is the time'
After one year of treatment, "practically no beta-amyloid plaques could be detected in patients who received the highest dose," said a university statement.
And while the trial was not designed to test drug efficacy, the team did observe a slower onset of symptoms in treated patients. This supported the hypothesis that amyloid plaques are indeed what cause Alzheimer's, the researchers said, but further tests are required to prove this.
"Indeed, confirmation that anti-AB (amyloid-beta) treatment slows cognitive decline would be a game-changer for how we understand, treat and prevent Alzheimer's disease," commented Eric Reiman at the Banner Alzheimer's Institute in Phoenix, Arizona.
"Now is the time to find out."
The drug did have side-effects, however, including fluid buildup on the brain, and headaches.
Alzheimer's disease is the most common form of dementia, which the World Health Organisation (WHO) says affects nearly 50 million people worldwide — with some 7.7 million new cases diagnosed per year. Old age is the major risk factor, and there has not been prevention or effective treatment for the disease so far. Alzheimer's causes memory loss and disorientation, as well as anxiety and aggressive behaviour.
Outside experts are also optimistic about the new study.
"Let's keep our fingers crossed for success in the next steps," said neuroscience professor Richard Morris from the University of Edinburgh.