'Breakthrough' Alzheimer's drug

British scientists today unveiled a drug that could be a potential breakthrough in the treatment of Alzheimer's.

Research at University College London has found the drug can halt the advance of the underlying cause of Alzheimer's, the most common form of dementia in the elderly. Early tests in the laboratory have been so successful clinical trials using a handful of patients will begin within weeks.

The drug, known as CPHPC, is thought to dissolve the damaging deposits of amyloid proteins which collect in the brain and form waxy plaques. Sufferers, who include Iris Murdoch and former US President Ronald Reagan, express an abnormal amount of the proteins.

The ability to learn and remember declines as these plaques grow. Today's generation of Alzheimer's drugs only treats symptoms.

"This is far from being a miracle cure, but the results are promising," said Professor Mark Pepys, who led the study, published today in the journal Nature.

After screening 100,000 compounds, Professor Pepys discovered the drug removes a protein called SAP in the blood that sticks to the clumps and prevents the body from breaking them down.

When they tested it on 19 patients with a disease called systemic amyloidosis, a rare illness in which the clumps form in different organs in the body, CPHPC targeted SAP and prevented it from attaching to the deposits, allowing the body to get rid of them.

Professor Pepys and his team, who collaborated with Swiss health care group Roche Holding AG, now believe the drug may also be able to help remove amyloid deposits that occur in Alzheimer's disease and type II, or adult onset, diabetes.

"It is a potential treatment for Alzheimer's because if our idea is right - that removal of SAP promotes disappearance of the amyloid deposits - this ought to happen in the patients with Alzheimer's as well," he said. "We believe that this is the first time that such a small drug is able to deplete a specific protein circulating in the body. It is doing an incredible vanishing trick.

"Even if everything works and the amyloid deposits disappear I can't guarantee that would arrest the progression of dementia. It might be it's too late by then."

But even if brain damage happens well before the deposits are fully formed the researchers have preliminary evidence removing SAP could still be beneficial.

Leslie Iverson, a pharmacologist at King's College London, said the new drug may also prove effective in treating Creutzfeldt-Jakob disease, which is also linked to insoluble protein plaques.

Dr Iverson said: "We can perhaps be hopeful that drugs can be found to combat the abnormal protein deposits seen in so many distressing human diseases."

The first generation of Alzheimer's drugs now on the market - Aricept, Exelon and Reminyl - produce some temporary improvement in cognitive functioning but do not tackle the underlying mental deterioration.

Roche has the rights to exploit CPHPC as a tre atment for Alzheimer's. But Professor Pepys says the underlying mechanism could have wider implications.

The Alzheimer's Society estimates that there are more than 700,000 people in the UK with dementia.

Alzheimer's is the most common cause of dementia. During the course of the disease the chemistry of the brain changes and cells, nerves and transmitters, are attacked. Eventually the brain shrinks as gaps develop.

The disease typically begins with lapses in memory, mood swings, and in difficulty finding the right words.