A NEW drug capable of halting Alzheimer's disease in its tracks was hailed yesterday as a "hugely exciting" development in the battle against the devastating condition.
The drug, developed and tested on patients in Scotland, slows down the progression of Alzheimer's by as much as 81 per cent.
Those given the drug in the ongoing trials, which have been running for 19 months, experienced no significant decline in their mental function.
It is thought that the drug – called rember – could be at least twice as effective in treating the disease as current medicines.
The results of clinical trials on 321 people – including 96 from the north-east of Scotland – were unveiled at a major conference in the United States.
Experts hope the drug, expected to be widely available within four years, could initially be used in the earliest stages of Alzheimer's to stop the disease progressing. However, in the longer term, people could be screened for signs of Alzheimer's before symptoms even start, meaning they can begin preventive treatment before problems set in.
The discovery offers hope to millions of patients around the world struck down by Alzheimer's. It could also help the National Health Service as it faces a growing bill for treating the country's ageing population, with forecasts of soaring rates of Alzheimer's in future.
Rember has been developed by a team at Aberdeen University, led by Professor Claude Wischik. Working with the university's spin-off company, TauRx Therapeutics, based in Singapore, the team developed a drug to target the tangles that form in the brain of Alzheimer's sufferers.
Rember is the first drug to act on these tangles, which cause memory loss and dementia.
The tangles are made up of a protein called tau, which forms inside nerve cells. They first destroy the nerve cells linked to memory and then destroy neurons in other parts of the brain as the disease progresses.
The study, presented at the International Conference on Alzheimer's disease in Chicago, focused on 321 people with mild and moderate Alzheimer's disease. They were divided into four groups, three taking different doses of rember and a fourth group taking a placebo.
At 24 weeks, experts found there were significant differences between the groups in relation to people with moderate Alzheimer's.
However, after 50 weeks, those with both mild and moderate Alzheimer's who were taking rember experienced an 81 per cent reduction in mental decline compared with those on the placebo.
Those on rember have not experienced a significant decline in mental function for the 19 months the trial has been ongoing, but those in the placebo group have got gradually worse.
Brain scans showed the drug had its biggest effect in those parts of the brain linked to memory, where the density of tau tangles is the greatest.
The drug works by dissolving the tau fibres and prevents a build-up of tangles. Larger Phase 3 trials are set to start next year, and the drug could be licensed by 2012.
The death of brain cells due to tangles can start over the age of 50, so early treatment could mean they can be caught before symptoms develop.
Prof Wischik said the results had been "unprecedented" in the treatment of Alzheimer's disease.
He added: "We have demonstrated for the first time that it may be possible to arrest progression of the disease by targeting the tangles, which are highly correlated with the disease.
"This is the most significant development in the treatment of the tangles since Alois Alzheimer discovered them in 1907."
Professor Stephen Logan, Aberdeen University's senior vice-principal, said the results were "hugely exciting".
He said the drug would initially be most useful in treating those in the early stages of Alzheimer's.
However, he added that the university was also working on developing a test to reveal the tangles in the brain long before symptoms start. No such test currently exists.
"It may be that you use a scan, such as a PET (positron emission tomography] scan, to identify the tau tangles and start treatment before someone even knows they have Alzheimer's," he said.
Such a test could be used on people with a family history of dementia, but in decades to come may also form part of an Alzheimer's screening programme targeting the whole population.
Prof Logan said it was not yet known how much the drug would cost – concern about the cost-effectiveness of current Alzheimer's treatments has seen campaigners take their cases to the High Court to press for increased access for patients.
The results of the new research were last night welcomed by health campaigners. Professor Clive Ballard, the head of research at the Alzheimer's Society, said: "This is a major new development in the fight against dementia.
"It is the first realistic evidence that a new drug can improve cognition in people with Alzheimer's, by targeting the proteins tangles that cause brain-cell death."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said the results of the trial were "encouraging".
She added: "This bodes well for a Phase 3 trial, but we need more human trials to assess the treatment's possible side-effects."
Prof Wischik and his team have spent 24 years investigating the structure of tangles in the development of Alzheimer's.
About 700,000 people in the UK suffer from dementia, and more than half of those have Alzheimer's.