The first drug that can prevent Alzheimer’s disease is finally on the horizon after scientists proved they can clear the sticky plaques from the brain which cause dementia and halt mental decline. Hailed as the "best news" in dementia research for 25 years, the breakthrough is said to be a potential "game changer" for people with Alzheimer’s.
If shown to be effective in larger trials, the first drug to prevent dementia could be available in just a few years.
"The results of this clinical study make us optimistic that we can potentially make a great step forward in treating Alzheimer's disease," said Prof Roger Nitsch, at the Institute for Regenerative Medicine at the University of Zurich.
“In the high dose group the amyloid has almost completely disappeared. The effect size of this drug is unprecedented.
“Despite it being a small sample there appeared to be a slowing of cognitive decline and functional decline. The group with a high degree of amyloid removal were basically stable. If we could reproduce this it would be terrific.”
The most common kind of dementia is Alzheimer’s disease, but scientists have been unable to reach consensus about the cause of the condition, and despite more than 400 drug trials, nothing has been shown to combat disease. The last Alzheimer's drug licensed in the U.K. became available more than a decade ago. Current treatments can reduce symptoms to some extent but doctors have nothing that can halt or slow progression of the disease.
Not only does the new study suggest a treatment for the disease, but shows that the build-up of amyloid plaque in the brain is likely to be to blame. Aducanumab is a treatment made up of antibodies, tiny y-shaped proteins that latch on to dangerous substances in the body, acting like flags, showing the immune system what to clear away.
Scientists tested various human immune cells with amyloid in a laboratory until they found one which produced an antibody that broke up the plaques. They then cloned it in large numbers for the new therapy, which is given intravenously just once a month.
In the trial, which was reported in the journal Nature, scientists tested varying levels of the drug over a year, as well as giving one group a placebo. They found that more amyloid was removed as the dose increased. Brain scans of those given the highest dose shown virtually no amyloid left at all.
The drug is likely to be most effective for patients in the very earliest stages of Alzheimer’s disease, or those who have not yet begun to show symptoms. Several universities are working on early blood tests for dementia which could pick the disease up a decade or more before the first physical signs appear. Dementia experts and charities said that the breakthrough offered real hope for the future treatment of Alzheimer’s disease.
"These results provide tantalizing evidence that a new class of drug to treat the disease may be on the horizon,” said Dr. David Reynolds, chief scientific officer at Alzheimer's Research U.K.
"The findings suggest that aducanumab may slow memory and thinking decline in people with early Alzheimer's and, although the analysis is only exploratory in this early trial, it paints a positive picture for ongoing trials with the drug."
Although some people on the trial experienced side effects such as headaches, scientists believe that adjusting the dose may alleviate problems. Prof David Allsop, Professor of Neuroscience, University of Lancaster, said: “This study shows convincingly that it is possible to reduce the extent of amyloid plaque formation in the brains of people with very early signs of dementia.
Encouragingly, this treatment also appeared to slow memory decline, demonstrating that amyloid formation is a direct or indirect cause of memory loss. This has been suspected for some time, but has never been proven in humans.
“These findings could be a game changer if the effects on memory decline can be confirmed in more extensive follow-on studies.”
The Alzheimer's Society said the "most compelling" evidence from the trial was the fact that more amyloid was cleared when patients took higher doses of the drug.
Dr. James Pickett, head of research at the charity, said: "No existing treatments for Alzheimer's directly interfere with the disease process, and so a drug that actually slows the progress of the disease by clearing amyloid would be a significant step.
Richard Morris, Professor of Neuroscience at the University of Edinburgh, said: “We cannot yet say we have a cure for Alzheimer's, as this is only a first step … but the importance of this first step cannot be understated.
“Let’s keep our fingers crossed for success in the next steps.”