Preliminary Study Indicates That IVIg Therapy May Improve Cognitive Function In Alzheimer's Patients

In what could prove to be an important development in the search for a treatment of Alzheimer's disease, New York-Presbyterian Hospital/Weill Cornell Medical Center physician-scientists say the results of an initial (Phase I) clinical study provide encouraging evidence that antibodies derived from human plasma can capture the beta-amyloid protein in blood and exert positive effects on patients' thinking abilities. Beta-amyloid is a central component of the senile plaque in the brains of Alzheimer's patients, and its toxicity against brain cells is believed to be a prime cause of the illness.

The study's investigators, however, caution that it's still far too early to hail IVIg as anything but "promising," and they do not currently recommend that physicians treat Alzheimer's patients with IVIg.

But, while preliminary, the findings—which were reported on Tuesday, April 12, 2005 at the annual meeting of the American Academy of Neurology (AAN) in Miami—do suggest the value of initiating larger, controlled Phase II clinical trials, and preparation for such trials are currently underway.

Intravenous immunoglobulin (IVIg)—an antibody product derived from human plasma and FDA-approved to treat other conditions, but not Alzheimer's— has been found to contain antibodies that latch onto beta-amyloid proteins in the blood. Previous studies have shown that antibodies against beta-amyloid can draw this protein out of the nervous system and reduce the burden of amyloid on the brain.

In the Phase I clinical trial, eight Alzheimer's patients were treated with IVIg, donated by Baxter Healthcare Corporation, and, to date, seven have undergone cognitive testing after six months of therapy. Cognitive function stopped declining in all seven patients and improved in six of the seven patients.

IVIg therapy was well-tolerated, with patients experiencing only minor and infrequent side effects, such as chills following the infusion.

"If these results are confirmed in larger, controlled trials, we might have a safe Alzheimer's treatment capable of clearing the amyloid protein away," says senior researcher Dr. Marc E. Weksler, The Irving Sherwood Wright Professor of Geriatric Medicine and Professor of Medicine at Weill Medical College of Cornell University in New York City. Dr. Weksler is also an Attending Physician at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

"These initial results are really encouraging," adds lead researcher Dr. Norman R. Relkin, Director of the Memory Disorders Program at NewYork-Presbyterian/Weill Cornell and Associate Professor of Clinical Neurology and Neuroscience at Weill Cornell Medical College. "Immune therapy for Alzheimer's disease has shown tremendous promise in the laboratory but has been difficult to translate into clinical practice. IVIg has the advantages of a well-established safety record and the benefits of containing antibodies that healthy individuals produce naturally as they age."

While it's too early to say for sure that IVIg is the optimal form of passive immunotherapy for Alzheimer's disease, Drs. Weksler and Relkin are very encouraged by the significant improvements in patients' thinking ability, as measured by cognitive testing, following treatment with IVIg.

"Although this is not a sufficiently large study or one designed to prove effectiveness, it does appear that our patients did considerably better than expected with this treatment," Dr. Relkin comments.

"Right now, we'd advise doctors against treating Alzheimer's patients with IVIg. There's still too much we don't know—especially the treatment's long-term effectiveness," they say. "We need to confirm these findings in larger, controlled trials before we can say anything definite."

Adapted from the following source: New York-Presbyterian Hospital/Weill Cornell Medical Center

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