Have scientists discovered a cure for Alzheimer's?

Scientists were amazed when a 20-year-old hay fever drug was found to be highly effective in treating dementia. Jeremy Laurance reports on a startling discovery

A hundred years after Alzheimer's disease was discovered, a cure for the degenerative condition that strips sufferers of their memory and personality remains a dream. The main advances have been in drugs to control symptoms such as agitation and restlessness. Restoring memory and cognitive ability has proved much harder.

That is why the publication last week of research showing that an old Russian drug once prescribed for hay fever may be the most effective treatment yet for the devastating condition has captured the attention of scientists and patients' groups.

A single 20mg pill of the drug, called Dimebon, taken three times a day, appears to be twice as effective in improving cognitive performance and preventing deterioration in memory as existing drugs.

The discovery was greeted by charities as perhaps the most exciting development in treatment of the disease. Existing drugs – cholinesterase inhibitors such as Aricept – have limited effects and were introduced over a decade ago.

According to the American researchers who led the trial, Dimebon is the furthest advanced of 65 agents being investigated for Alzheimer's, and holds the most promise.

However, British experts cautioned that the results were from a single trial of the drug, which is not licensed for Alzheimer's, and said further studies were necessary. A second international trial of the drug, which started last month in the USA, Europe and South America, is due to be completed by the end of the year.

Dimebon was used as an antihistamine in Russia 20 years ago, but it was withdrawn from the market when newer drugs superseded it. Investigations by the Russian Academy of Sciences revealed that it had a potential neuroprotective effect and it was bought by a US company, Medivation.

The company asked Professor Rachelle Doody, director of the Alzheimer's and Memory Disorders Center at the Baylor College of Medicine in Houston, to lead the randomised trial run by American and Russian scientists. It involved 183 patients with mild to moderate Alzheimer's in 11 hospitals in Russia.

Doody, who set up the Houston centre in 1987, is one of the world's leading researchers on Alzheimer's. She was the lead investigator in the trials of Aricept, the best-known existing Alzheimer's drug.

The results of the Dimebon trial she led, published last week in The Lancet, show that it improved performance on all five rating scales used to assess Alzheimer's patients, including cognitive performance, behaviour and capacity to carry out ordinary daily activities. Patients taking the drug scored better than they did at the start of the study, while those taking placebo got worse over the initial six-month period of the trial.

In a smaller group of patients who continued with the drug for a further six months, an even greater gap of 6.9 points on the cognitive performance test opened up between those on the drug and those on placebo. This compares with a 2.5- to three-point gain in trials of existing drugs.

Doody said: "I was surprised that all five of the outcome measures were positive and that the benefit [against placebo] widened over time. You don't see that with the other drugs... But this wasn't a comparison study – you can't say that makes Dimebon better than the other drugs."

She added: "I am very happy with the results. They show a clear signal and I am hopeful that the new international study which started last month will replicate them. US regulators have indicated that the trials are potentially acceptable as evidence for approval [for a licence]. There are a couple of dozen agents I am working on, and 65 that I follow, and the good news is that this is the furthest along in Alzheimer's research."

Clive Ballard of the Alzheimer's Society said the findings were "encouraging" and the discovery of a new application for an old drug was "potentially exciting". But it was a single trial of a small size and the results needed confirming, he said.

Caution was also expressed by Professors Alastair Burns of the University of Manchester and Robin Jacoby of the University of Oxford, who wrote in a commentary in The Lancet: "Addition of treatment options is good news for patients and clinicians – it promotes choice and offers the possibility of bespoke treatment packages which maximise the chances of response. [The] trial shows that Dimebon is better than placebo which is no mean feat considering the positive placebo responses in dementia."

But Jacoby said that he retained a "healthy scepticism" about the findings. "They need to be replicated before I will start prescribing it," he said.

If the results are replicated, it will be a boost for a new approach to drug research – taking old drugs and investigating their potential in other areas of medicine. Old drugs can go rapidly into clinical trials for new conditions because they are known to be safe. This speeds up development and cuts the cost.

A cure for Alzheimer's is not imminent, but it's good news that an old drug may be an effective treatment. Everything hangs on the second Dimebon trial now under way.

Alzheimer's: the facts

About 400,000 people suffer from Alzheimer's in the UK and 25 million worldwide.

It is the commonest form of dementia, costing £17bn in the UK for care and treatment.

The condition is caused by the accumulation of protein deposits in the brain, producing the dementia symptoms.

There are three drugs that claim to halt the progress of the disease (but not to reverse it) – Aricept, Reminyl and Exelon.

In 2006, the NHS's use of these drugs was restricted to the moderate stage of the disease by the National Institute for Clinical Excellence because of their limited effect.

There are currently no drugs available on the NHS for the tens of thousands of patients in the UK with mild Alzheimer's.

PROMOTED VIDEO
Life and Style
ebookNow available in paperback
ebooks
ebookPart of The Independent’s new eBook series The Great Composers
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Tradewind Recruitment: English Teacher

    Negotiable: Tradewind Recruitment: My client is an excellent, large partially ...

    Tradewind Recruitment: Science Teacher

    £90 - £140 per day: Tradewind Recruitment: I am currently working in partnersh...

    Tradewind Recruitment: Year 3 Primary Teacher

    £100 - £150 per day: Tradewind Recruitment: Year 3 Teacher Birmingham Jan 2015...

    Ashdown Group: Lead Web Developer (ASP.NET, C#) - City of London

    £45000 - £50000 per annum + Excellent benefits: Ashdown Group: Lead Web Develo...

    Day In a Page

    Isis hostage crisis: The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power

    Isis hostage crisis

    The prisoner swap has only one purpose for the militants - recognition its Islamic State exists and that foreign nations acknowledge its power, says Robert Fisk
    Missing salvage expert who found $50m of sunken treasure before disappearing, tracked down at last

    The runaway buccaneers and the ship full of gold

    Salvage expert Tommy Thompson found sunken treasure worth millions. Then he vanished... until now
    Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

    Homeless Veterans appeal: ‘If you’re hard on the world you are hard on yourself’

    Maverick artist Grayson Perry backs our campaign
    Assisted Dying Bill: I want to be able to decide about my own death - I want to have control of my life

    Assisted Dying Bill: 'I want control of my life'

    This week the Assisted Dying Bill is debated in the Lords. Virginia Ironside, who has already made plans for her own self-deliverance, argues that it's time we allowed people a humane, compassionate death
    Move over, kale - cabbage is the new rising star

    Cabbage is king again

    Sophie Morris banishes thoughts of soggy school dinners and turns over a new leaf
    11 best winter skin treats

    Give your moisturiser a helping hand: 11 best winter skin treats

    Get an extra boost of nourishment from one of these hard-working products
    Paul Scholes column: The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him

    Paul Scholes column

    The more Jose Mourinho attempts to influence match officials, the more they are likely to ignore him
    Frank Warren column: No cigar, but pots of money: here come the Cubans

    Frank Warren's Ringside

    No cigar, but pots of money: here come the Cubans
    Isis hostage crisis: Militant group stands strong as its numerous enemies fail to find a common plan to defeat it

    Isis stands strong as its numerous enemies fail to find a common plan to defeat it

    The jihadis are being squeezed militarily and economically, but there is no sign of an implosion, says Patrick Cockburn
    Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action

    Virtual reality: Seeing is believing

    Virtual reality thrusts viewers into the frontline of global events - and puts film-goers at the heart of the action
    Homeless Veterans appeal: MP says Coalition ‘not doing enough’

    Homeless Veterans appeal

    MP says Coalition ‘not doing enough’ to help
    Larry David, Steve Coogan and other comedians share stories of depression in new documentary

    Comedians share stories of depression

    The director of the new documentary, Kevin Pollak, tells Jessica Barrett how he got them to talk
    Has The Archers lost the plot with it's spicy storylines?

    Has The Archers lost the plot?

    A growing number of listeners are voicing their discontent over the rural soap's spicy storylines; so loudly that even the BBC's director-general seems worried, says Simon Kelner
    English Heritage adds 14 post-war office buildings to its protected lists

    14 office buildings added to protected lists

    Christopher Beanland explores the underrated appeal of these palaces of pen-pushing
    Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

    Human skull discovery in Israel proves humans lived side-by-side with Neanderthals

    Scientists unearthed the cranial fragments from Manot Cave in West Galilee