A DRUG invented by a scientist in Scotland has halted the progression of Alzheimer’s disease in a medical first.

In results lauded as the most promising indication a treatment for the neurological condition is on the horizon, brain deterioration was stopped for 18 months in some patients.

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Created by Claude Wischik, of the University of Aberdeen, the drug could soon be the first ever medicine - taken as a twice daily tablet - given to Alzheimer’s patients to stave off the debilitating disease.

The final-stage trial initially seemed to have failed as the drug did not help patients who were on other dementia medicines.

But among the 15 per cent of the 891-strong trial taking only Professor Wischik's drug, it appeared to have a significant effect.

These patients saw no decrease in their ability to undertake everyday tasks over 18 months, nor in their memory or reasoning skills.

Furthermore key areas of their brain shrank a third less than other patients in the trial.

Professor Wischik says the drug, called LMTX or LMTM, will fulfill the promise made by world leaders in 2013 to find dementia treatments within a decade.

He added: "This is wonderful.

"I would like the drug to have just worked unequivocally in the whole population.

"But that’s science.”

The Alzheimer’s Association International Conference in Toronto was presented the results by Serge Gauthier, of McGill University.

He said: "There is a pattern of disease modification here.

"This is the first time it has happened in our field that a drug reduces the rate of brain atrophy.”

Speaking to The Times, Dr Gauthier said it was a surprise other drugs seemed to have a deleterious impact on LMTX.

However he suggested that in a similar way cancer patients' medicine regimes can be switched up should a treatment cease working, so Alzheimer’s patients could be given LMTX as a first-choice drug.

He added: “In a field that has been plagued by consistent failures of novel drug candidates in late-stage clinical trials and where there has been no practical therapeutic advance for over a decade, I am excited about the promise of LMTX."

Currently patients are prescribed drugs which help to control symptoms for a time, but do not stop further damage to the brain, the main aim of dementia research.

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The new treatment, based on a blue dye, aims at dissolving a protein called tau, preventing it from forming tangles that kill off nerve cells.

Professor Wischik is developing it through a spin-off company and is aiming to apply for a licence after the publication of the results of a second trial later this year.

Doug Brown, director of research at the Alzheimer’s Society, said: “After years of failure we are now starting to see glimmers of hope.

"There are still lots of questions to answer before we know how promising this new treatment could be — why it doesn’t appear to work in those who are already taking other medications?”

Others in the scientific community have counselled caution, with some warning that looking only at a smaller group with a trial increased the risk of positive results appearing by chance.

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Alzheimer’s Research UK said that although the trial marked an important step, further trials were needed to confirm them.