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Monday, 23 July, 2001, 09:32 GMT 10:32 UK
Alzheimer's vaccine trials 'promising'
The vaccine could help patients with Alzheimer's
Scientists are planning large-scale trials of a vaccine for Alzheimer's disease which has been proved to be safe for humans.

It is hoped the further trials will produce the same results as tests on mice which showed the vaccine was able to protect against Alzheimer's, if the injection was given at an early age.

In other mice who had Alzheimer's, the disease was halted or even reversed.

Initial trials on 100 patients from the US and UK found that the vaccine was safe and well tolerated in humans - mirroring the first findings in experiments on mice.

A lot of valuable information will come out of the trial

Harry Cayton
The scientists, from Elan Pharmaceuticals, now plan to test the vaccine on 375 Alzheimer's patients from across the US and Europe.

This second stage of research will show if the vaccine can help patients with mild to moderate Alzheimer's.

The vaccine is called AN-1792.

When the first indications of the vaccine's safety were announced last July at the World Alzheimer's Society in Washington DC, Dr Dale Schenk, vice president of discovery research at Elan Pharmaceuticals, said: "We are extremely pleased with the progress of our phase one trials which have shown that AN-1792 is well tolerated by the patients.

"During the course of our research, we also developed a greater understanding of how the vaccine works to clear amyloid plaques out of the brain and prevent additional plaques from forming."

Enough patients developed an immune response to the vaccine for the second stage of the tests on humans to go ahead.

They are likely to start later this year, and take two years to complete.

Brain plaques

Amyloid plaques, protein deposits which impede and kill nerves in the brain, are a hallmark of Alzheimer's disease, although scientists do not know if they are a cause or a result of the illness.

The vaccine is a synthetic form of naturally occurring beta amyloid protein, the main component of the plaques.

Scientists found that when injected into mice, the compound prompted an immune response which increased the clearance of amyloid plaques.

Antibodies were formed which bound themselves to the plaques and allowed them to be engulfed by other immune system defenders called microglial cells.

Dr Schenk said: "Amyloid plaques act as a brain invader. We are optimistic that we can attack this invader at its source and eventually help the millions of people and families world-wide who are living with this devastating disease."


Harry Cayton, chief executive of the Alzheimer's Society said: "We are pleased to know that the trials continue to be promising.

"Although in the end the vaccine may not be fully effective in humans, a lot of valuable information will come out of the trial, and a number of other promising areas of research are being pursued."

A spokesman for the Alzheimer's Research Trust told BBC News Online: "This is an important step. If the vaccine works at all, either in preventing plaques or in reducing symptoms, that will help to answer our first question about the causes of the trouble.

"If it really has a long-term effect in preventing symptoms, which would be better than any current therapy, that would be very exciting indeed.

"We'll have to wait at least 3 years for some preliminary answers'

See also:

11 Jul 00 | Health
Alzheimer's vaccine 'safe to use'
06 Jun 01 | Health
Vaccine hope for Alzheimer's
21 Dec 00 | Health
Alzheimer's vaccine breakthrough
20 Dec 00 | A-B
Alzheimer's disease
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