Health Story

03 December 2008 01:40 BST

"Breakthrough" research for Alzheimer's disease

Two new studies published in the Lancet today have provided hope for better treatment of Alzheimer's disease.

One showed that a drug once used in Russia as an antihistamine could reduce the symptoms of the form of dementia while the other study showed that drug vaccination could remove plaques in the brain associated with the disease.

For the first study researchers at the Baylor College of Medicine, United States, and colleagues did a controlled trial to test the safety and success of the orally-taken drug Dimebon in the treatment of 183 patients with mild to moderate Alzheimer's disease.

Patients were assessed over six months using a scale that measures brain function such as thinking and memory.

They found that it significantly improved the course of the disease and that benefits increased over the course of 12 months.

Commenting on the trial, Susanne Sorensen, head of research at the Alzheimer's Society, said: "This encouraging research suggests Dimedon may be an effective treatment for the symptoms of Alzheimer's disease. These initial findings imply that Dimedon could be more effective than treatments currently licensed for people with Alzheimer's, however this was a modest sized study.

"More substantial research is now needed, which studies more people over a longer period of time, to investigate the true value of this drug and whether it treats Alzheimer's disease itself or just the symptoms."

In the second study British researchers discovered that drug vaccination can remove amyloid plaques in the brains of people with Alzheimer's disease but that this did slow down the disease.

The five-year study examined 80 patients with mild to moderate dementia who had been immunised with AN1972, a drug which acts to clear these plaques from the brain.

Contrary to predictions, removal of amyloid plaques did not result in an improvement in cognitive function or survival. Several patients with complete plaque removal deteriorated severely.

As such the previous consensus among dementia scientists - that removing amyloid plaques is key to defeating Alzheimer's - may now need to be rethought.

Lead researcher Professor Clive Holmes of the University of Southampton said: "Our results suggest that brain deterioration can occur in Alzheimer's despite the removal of plaques.

"It may be that these toxic plaques trigger the neurodegeneration but don't have an ongoing role. This study opens up numerous avenues for further research."

Rebecca Wood, chief executive of the Alzheimer's Research Trust, commented: "This is groundbreaking research, and a leap forward in our understanding of Alzheimer's disease.

"It is disappointing that anti-amyloid treatments did not prevent the disease's progress, but we still need to do more research into whether earlier removal of this initial 'motor' of the disease could slow its progression. These findings underline the need to take a variety of research approaches in a multi-pronged attack on this devastating disease."