Scientists from Aberdeen University have found the treatment, known as LMTX, could offer sufferers of the degenerative neurological disorder an extra 15 years of lucidity.
It is believed to be twice as effective as other drugs currently on the market.
Campaigners said the development could provide “a great deal of interest and hope” for the 90,000 Scots living with dementia, but warned that more concrete information was needed.
The drug dissolves proteins, known as tau, which stop working properly in patients with dementia and clump into tangles in the brain.
Professor Claude Wischik, of Aberdeen University, who is leading the research, said: “In the phase-two tests [to test effectiveness after safety has been determined], this drug achieved a 90 per cent reduction in the rate of progression on clinical measurements, and it achieved a similar effect on the rate of loss of brain function, as measured by brain scans.
“In total we have 1,910 patients enrolled so far; the clinical trials are being conducted in more than 200 clinics around the world in 20 countries. If all goes well, 2017 could be when we see this drug in the pharmacies.”
Phase-two clinical trial results showed that the drug slowed down the progression of the illness and stopped further health deterioration compared to current treatments which give patients a temporary mental health boost. Aberdeen University researchers who are working with TauRx Therapeutics – a Singapore-based company “spun out” of the university – hope that LMTX could also be prescribed as a preventative measure if it proves to be a success.
MRI scans have shown that the new drug has worked on the brains of patients taking part in clinical trials, in one case reversing some of the symptoms for up to 11 years before the patients began to decline again.
Professor Wischik said that there have only been purely symptomatic treatments previously, which can help to provide short periods of lucidity amongst patients.
He said: “So they’re not really treatments in any sense; whereas our treatment, we think, as we have certainly found in phase-two testing, will arrest the progression.
“I don’t know how long it will work for – two years, three years, 15 years – but it will be way, way longer than the current treatments on the market.”
The news was welcomed by Jim Pearson, director of policy and research at Alzheimer Scotland, who called for more research into causes and treatments of the disorder.
He said: “This is a promising announcement and is likely to prompt a great deal of interest and hope.”