'Stunning' find: cancer drug reverses Alzheimer's in mice

A SKIN CANCER drug has been found to rapidly reverse the symptoms of Alzheimer's disease in mice. Scientists who made the "stunning" discovery say they are about to begin trials to see if the drug works the same way in humans.

Researchers from Case Western Reserve School of Medicine in Cleveland, Ohio, gave bexarotene - trade name Targretin - to mice genetically engineered to develop Alzheimer's symptoms.

The drug removed up to 75 per cent of amyloid, a protein which forms the brain plaques associated with Alzheimer's. The treatment improved the memory of mice which exhibited improvements in nest building, maze performance and remembering electrical shocks.

In contrast to other treatments, which can take months to reduce amyloid levels, bexarotene worked appreciably within six hours. Within three days, the drug had removed half the amyloid build-up. The team's findings have been published in the journal Science.

"When we saw the effects of the drug on amyloid we were stunned," Professor Gary Landreth, a lead researcher, told Channel 4 News.

The team is about to start trials of bexarotene in healthy humans to see if it causes the same biochemical changes as in mice. After that, they might apply the same treatment to humans with Alzheimer's.

However, Landreth warns against talk of a cure for Alzheimer's, which is becoming ever more common as human life expectancy increases.

"We need to be clear - the drug works well in mouse models of the disease. Our next objective is to ascertain if it acts similarly in humans."

But there are major questions over whether the approach taken by Landreth's team - clearing amyloid plaques - will ever work in humans. Retinoids, the class of drugs which includes bexarotene, can also cause harmful side-effects.

David Allsop, professor of neuroscience at Lancaster University, told the BBC: "I would say that the results should be treated with cautious optimism. It looks promising in the mouse model but, in recent years, these types of experiments in mice have not translated well into humans." · 

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