New drug that halts mental decline is ‘best news for dementia in 25 years’

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.

Scientists said they were amazed to find that patients treated with the highest dose of the antibody drug aducanumab experienced an almost complete clearance of the amyloid plaques that prevent brain cells communicating, leading to irreversible memory loss and cognitive decline.

Crucially they also found that after six months of the treatment, patients stopped deteriorating compared with those taking a placebo, suggesting that their dementia had been halted.

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.”

Dr Alfred Sandrock, from the Massachusetts-based biotech company Biogen, which is hoping to bring the drug to market, said: “This is the best news that we have had in our 25 years and it brings new hope to patients with this disease.”

There are currently 850,000 people living with dementia in Britain, a figure that is expected to rise to one million by 2025 and two million by 2050.

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 UK 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.

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