Alzheimer vaccine passes crucial test

LONDON - The first vaccine to show promise against Alzheimer's, the degenerative brain disease affecting up to 500,000 people in Britain, has passed an important hurdle in human trials.

Initial results from a phase-one trial of the vaccine in the US, designed to test its toxicity, showed no obvious safety concerns, researchers reported.



Further trials will be conducted on 100 patients in the US and Britain, but researchers said the early results, presented at the World Alzheimer's Congress in Washington, were encouraging.

However, it will be at least two years before they will know whether the vaccine, already shown to be effective in mice, can help people with Alzheimer's, the most common form of senile dementia.

The scientists, from Elan Pharmaceuticals in California, reported a year ago in the science journal Nature the results of experiments on transgenic mice - genetically altered to develop the distinctive protein deposits called "plaques" seen in the brains of people with Alzheimer's.

An injection of the vaccine, a synthetic version of the naturally occurring beta amyloid protein, significantly reduced the formation of the plaques.

Although the finding was impressive, some scientists warned at the time that the vaccine might not prove safe in humans. That fear now looks as though it could be dispelled.

The strongest theory about the cause of Alzheimer's is that the plaques interfere with the function of nerve cells in the brain and cause nerve cell death, accounting for the mental deterioration associated with the disease. But it is not yet known whether the plaques are the result or the cause of the disease process.

The director of the Alzheimer's Disease Society in Britain, Harry Cayton, said the research was potentially very interesting, but he warned against raising expectations.

- INDEPENDENT