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Alzhemier's vaccine shows promise in mice

By STEVE MITCHELL, Medical Correspondent

WASHINGTON, Aug. 11 (UPI) -- U.S. researchers said Thursday they have developed a vaccine given via the nose that appears to reverse the course of Alzheimer's disease in mouse models, and they want to test it in humans as quickly as possible.

Mice given the vaccine showed a significant reduction in the levels of a brain substance called beta-amyloid plaques, which are thought to play a role in causing Alzheimer's.

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"This is a novel vaccine approach for treating Alzheimer's that can be given by the nasal route," Dr. Howard Weiner, the head of the research team and co-director of the Center for Neurologic Diseases at Brigham and Women's Hospital in Boston, told United Press International.

"We think this is ready to begin testing in humans," Weiner added. His team currently is preparing a formal request to the U.S. Food and Drug Administration for approval to conduct studies in people. If the FDA approves the request, Weiner said he anticipates beginning the first human trials in 2006.

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Alzheimer's, which affects more than 18 million people worldwide, is a degenerative brain disease that impairs memory and thinking ability. There is no cure, and the disease eventually results in death due to loss of brain function.

A previous vaccine being developed by Elan Pharmaceuticals had looked promising for treating Alzheimer's, but a clinical trial was halted in 2002 when researchers discovered that some patients who were given the vaccine developed a potentially fatal brain inflammation called meningoencephalitis.

The vaccine tested by Weiner's team consists of a multiple-sclerosis drug called Copaxone, manufactured by Teva Neuroscience, and a compound called Protollin, made by ID Biomedical Corporation, that has been tested in humans. The researchers discovered the new vaccine while seeking to understand how the Elan vaccine might have triggered meningoencephalitis.

Dr. Stephen Snyder of the National Institute on Aging in Bethesda, Md., called the mouse findings, which appear in the September issue of The Journal of Clinical Investigation, "really important."

Snyder told UPI it sounded reasonable to pursue human trials "because the two materials (incorporated in the vaccine) have been used in humans and don't have any serious side effects."

He said there still might be some hurdles to overcome, however. The mouse Alzheimer's plaques are different than the human plaques, and it is not known whether the vaccine reduces another brain substance called ADDLs, which also might play a role in causing Alzheimer's.

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"This is still a neat finding, and it represents a step up in order of magnitude, at least in safety, so that's got to be a good thing," Snyder said.

The only way to know for sure whether this will work in humans is to go forward with studies in people, he added.

In the study, transgenic mice that mimic human Alzheimer's were inoculated with the vaccine. Weiner's team found a 73-percent reduction in levels of beta-amyloid plaques in the mice.

Weiner said he thinks the substances in the vaccine are stimulating special immune-system cells in the brain called microglial cells to clear out the plaques.

"The adjuvant (Protollin) helps activate the cells, and the multiple-sclerosis drug is amplifying that effect," he said.

Weiner said both Teva and ID Biomedical Corporation are interested in seeing the vaccine go forward in human studies.

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