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Study: Human Plasma Boosts Mental Skills in Alzheimer's Patients

Posted on: Wednesday, 13 April 2005, 00:00 CDT

Apr. 13--MIAMI BEACH -- The mental skills of a small group of Alzheimer's patients improved after antibodies derived from human plasma were infused directly into their blood, according to a promising new study.

The researchers said they were hoping just to stabilize the patients.

"Much to our surprise, the patients showed clear signs of improvement," said co-author Norman Relkin. "Some of them started telling stories again. They started socializing again."

Because the study involved just eight patients, at this point the treatment only can be considered promising, according to Alzheimer's researchers not associated with the study.

"This is still quite far from a potential treatment," said Sanjay Asthana, head of geriatrics at the University of Wisconsin Medical School in Madison. "There is great promise in terms of the science, but this study is very, very early."

A potential benefit to the new treatment is that it uses a blood product that has been around for 30 years and that has an established safety record, said Piero Antuono, an Alzheimer's specialist at the Medical College of Wisconsin and Froedtert Lutheran Memorial Hospital.

"The results look promising and the tool that they are using is not high science," Antuono said. "If cognitive aspects are improving, you don't need to prove how the drug works."

Encouraged by the results, researchers are planning two larger trials, one of which is scheduled to begin later this year.

The treatment, which was presented at the American Academy of Neurology annual meeting here, is one of several experimental therapies under way that target beta-amyloid, the protein that accumulates in the brain of Alzheimer's patients and that is believed to cause brain cells to die.

The new approach is similar to other so-called Alzheimer's vaccines, in that it relies on antibodies to target amyloid-beta.

An earlier trial of an active vaccine that stimulated the immune systems of patients to produce their own amyloid-beta antibodies was stopped in 2002 when 15 patients developed severe swelling in the brain.

The new approach uses a form of passive immunization in which existing antibodies are infused into the blood at various times, anywhere from once a week to once a month.

"This is another idea of how to do it, naturally," said Neil Buckholtz, chief of the dementias of aging branch of the National Institute on Aging, part of the National Institutes of Health. "Conceptually, it's very interesting."

The trial was funded primarily by Baxter Bioscience, which makes the plasma product that was studied, along with support from several other organizations, including NIH and the Alzheimer's Association.

The trial was started after Relkin and others reported in 2002 that Alzheimer's patients had three times fewer antibodies to amyloid-beta in their blood.

They tried intravenous immunoglobulin (IVIg), an antibody product that has been safely used for decades to treat other immune system condition s in hundreds of thousands of patients, said Relkin, director of the memory disorders program at New York Presbyterian/Weill Cornell Medical Center.

It is believed that IVIg binds to amyloid-beta, making it more difficult for the protein to clump around brain cells.

In addition to increasing levels of both amyloid-beta antibodies and amyloid-beta in the blood, researchers reported that levels of amyloid-beta decreased in cerebrospinal fluid of the patients, a sign that the antibodies were decreasing amyloid-beta in the brain.

The treatment is a relatively simple approach that uses a widely available plasma product that also contains other components and vast numbers of other antibodies, said Sam Gandy, a spokesman for the Alzheimer's Association.

"It's an interesting thing to try while we are going on with much more sophisticated strategies," said Gandy, director of the Farber Institute for Neurosciences at Thomas Jefferson University, who was not involved with the study. "In the long run, we want the one silver bullet."

For the study, eight people with mild to moderate Alzheimer's were treated with various doses of IVIg.

Over the course of six months, they underwent cognitive testing using a standard 30-point exam.

The typical Alzheimer's patient has a drop of 1.5 points over the course of six months, Relkin said.

"Our patients improved three points in six months," he said.

Cognitive decline stopped in all seven patients that had undergone testing and improved in six.

In addition to needing to replicate the results in a larger group of patients, the researchers will need to image the brains of the patients to see if beta-amyloid plaques in the brain actually are decreasing, Gandy said.

Although IVIg is widely available, it costs about $3,000 to $7,000 a month, Relkin said.

And even though it is approved for other uses, he said Alzheimer's patients should not be put on the drug.

A limited amount of the drug is produced and a surge in use by Alzheimer's patients could result in people with other diseases being deprived of the medicine, he said.

Indeed, patients now may pressure doctors to put them IVIg, said Antuono of the Medical College and Froedtert.

"If we would say 'yes,' it would exhaust all our IVIg at Froedtert in a week," he said. "There is going to be the potential for misuse."

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Source: The Milwaukee Journal Sentinel

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