Alzheimer's disease affects more than 500,000 people in Britain, yet there is no cure and little treatment after the early stages. But a new drug has been released this month which can help people in the later stages of the disease. Lisa Salmon reports on how Alzheimer's affects people and how the new drug can improve their lives.

THE torment of knowing your partner or parent is unable to recognise you or care for themselves must be immense. Yet it happens every day in hundreds of thousands of UK homes where people live with Alzheimer's disease.

There is no cure for the condition which affects around 500,000 people in this country. But there may, at last, be some hope on the horizon for Alzheimer's sufferers and their carers, thanks to a new drug.

The drug, Ebixa, slows down the progression of the disease by blocking excess amounts of a chemical in the brain which disrupts memory and cognitive function in Alzheimer's patients.

It is the first drug for use in the middle and severe stages of the disease - three other drugs are only effective if used in the early stages. Trials on more than 4,000 people worldwide have shown that patients on Ebixa tend to retain their memory longer, have improved or stabilised thought processes and are better able to function in their daily lives.

Trial lead investigator Professor Barry Reisberg says: "Ebixa is exciting because it is in the first of a new class of agents and should provide real benefit to those patients with severe dementia.

"For example, patients on Ebixa may be more able to retain their ability to wash and dress themselves compared to non-treated patients."

Ebixa has been developed by the Danish-based pharmaceutical company Lundbeck, whose head of research, Claus Braestrup, says trials to date have shown that the effects last at least a year.

He says: "We expect it will be longer, but we don't know yet.

"The drug is much better than we expected. This is the first time we have been able to give hope to people with severe Alzheimer's. It seems to have an almost immediate effect."

The drug has been welcomed by The Alzheimer's Society, which believes it could improve the lives of both sufferers and their carers.

But it is concerned that the drug, which is available in Britain from this month and costs around £900 a year, may not be prescribed to all sufferers because of the so-called postcode lottery in the NHS.

Harry Cayton, the society's chief executive, says: "This is a seriously important breakthrough, although it's not a cure. It's not going to make people better, but it will improve their quality of life and help them be more independent."

But Cayton says the possibility of a postcode lottery for the drug means people may have to push to get it.

"We don't know who will be prescribing it and who won't be," he says. "It's entirely dependent on individual doctors and individual health authority budgets. Families need to find out more about it and push for it if it looks like the right thing.

"This drug will not stop the disease, but it is a definite step forward in treating it."

The disease is age related, with one in ten people over 65 falling victim to it, compared to one in a thousand under 65. The risk increases to one in five over the age of 80, and the number of cases is expected to rise substantially in the near future because of the ageing population.

Victims of the disease include former US president Ronald Reagan, who no longer recognises his wife Nancy, and the late Iris Murdoch.

What causes Alzheimer's is not known, but it involves the build-up of clumps of proteins in the brain - known as 'plaques' and 'tangles' - and slow degeneration of brain function.

This leads to memory loss, inability to perform previously routine tasks and personality and mood changes.

The average life expectancy after diagnosis is seven to ten years, with patients becoming so frail that they lose the ability to swallow and eat, or die from complications such as pneumonia.

It is an awful thing for both the sufferers and their nearest and dearest, who often end up being their carers.

Barbara Pointon has been looking after her husband Malcolm for the last 11 years. Malcolm, now 62, is in the last stages of the disease and can no longer wash or dress, feed himself or understand what is being said to him.

She says: "I do everything for him. I feel as though my life's on hold and it's very tiring, but I do it because I love him and will stick by him.

"I mourn for the Malcolm I knew before the Alzheimer's. He was such a lovely, talented person.

"But I can't just let our shared history go. I feel the real Malcolm is still in there, but he's just a shadow of what he was."

Malcolm's illness is now too severe to be treated by drugs but Barbara is still extremely hopeful about Ebixa for other victims.

"If it can stop people having to go through what Malcolm has, it can only be a good thing."