http://www.cnn.com/2001/HEALTH/07/23/alzheimers.vaccine/index.html
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Alzheimer's
vaccine passes key test
July 23, 2001 Posted: 7:53 AM EDT (1153
GMT)
By Rhonda Rowland SAN FRANCISCO (CNN) -- An experimental
vaccine designed to fight Alzheimer's disease appears to be safe in humans
and is showing an immune response, according to scientists with Elan
Corporation. The scientists report they have concluded the
first phase of testing designed to assess safety, and will now take the
vaccine into phase two clinical trials by the end of 2002. Alzheimer's is a degenerative disease of the
brain that inexorably attacks nerve cells, causing impairment and loss of
memory and mental functions. Worldwide, 22 million people are expected to
develop the disease by the year 2025.
"We're extremely excited -- we're on the
frontier of a completely novel approach to Alzheimer's disease," Dr.
Ivan Lieberburg, executive vice president and chief scientific and
medical officer of the Elan Corporation, told CNN. The vaccine, called AN-1792, was studied in 100
patients with mild to moderate Alzheimer's disease in the United States and
the United Kingdom. The trials lasted more than a year. "The product showed that is was safe for
patients and we didn't see any significant problems with it other than sore
arms at the injection site, which is what you would expect," Lieberburg
said. "More importantly, as well we saw that in a
significant proportion of the patients they were able to demonstrate an
immune response. Their antibody levels went up and that indicates that this
was having an effect in these patients," he said. The scientists did not indicate any cognitive or
memory improvements in the patients but said they were reacting to the
vaccine as mice did in previous experiments. Remarkable results in mice
Elan is developing the vaccine with Wyeth-Ayerst
Laboratories, the pharmaceutical division of American Home Products. Two years ago, Elan researchers reported
remarkable results of the vaccine in mice. Mice immunized at a young age were
protected from Alzheimer's; in animals that already had the disease, the
disease was halted and in some cases reversed. "We're hoping that if we see anything like
what we saw in our mice experiments in people in phase two clinical study,
that this would be a truly remarkable result," Lieberburg said.
The Alzheimer's Association said Elan's
announcement is an exciting development but should not preclude other avenues
of research to find a way of preventing or curing the devastating disease. "I think it's very exciting to see this
product moving forward because it is going to be a test of one of the
fundamental theories of Alzheimer's disease," said Dr.
William Thies, vice president of medical and scientific affairs at the
Alzheimer's Association. "While we don't know whether the product is
going to work, we're going to find out an awful lot of valuable information
no matter what the outcome of the trial is." Vaccine attacks plaques
The vaccine is designed to attack and clear out
the characteristic beta amyloid plaques seen in the brains of Alzheimer's
patients. There is still some debate over whether the amyloid plaques are the
cause of Alzheimer's dementia. "If it turns out that the vaccine clears
the protein out and it still doesn't affect the disease, then that's a clear
indication that amyloid is not the causative factor," said Thies. If the vaccine does affect the disease process,
it will not be able to cure the disease. "For people who have well-established
disease, the vaccine can do nothing to return dead brain cells and certainly
can't return memories," said Thies, "although it could potentially
arrest the disease in whatever stage the individual is in." The next phase of testing will include 375
Alzheimer's patients at multiple centers in the United States and Europe. The
trials are expected to last about two years.
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