The first long-term treatment shown to halt the progression of Alzheimer's disease is being hailed by experts at the Alzheimer's Association International Conference 2012 in Vancouver, Canada.
The treatment, still in testing, is an immune therapy called IVIG/Gammagard that has been given intravenously for three years to a small group of participants. The findings, reported Tuesday, follow nine years during which no new drugs have been discovered for the incurable disease, affecting 5.4 million people in the USA.
Participants did not show improvement in most of the Alzheimer's symptoms they had, but neither did they show further decline on measures of cognition, memory, daily functioning or mood. Alzheimer's is fatal and wipes away personality, memory and cognition. No therapy on the market has stopped this deterioration.
"If the final trial is successful, this will provide a direction for treatment," said study leader Norman Relkin of Weill Cornell Medical College in New York City. "The key thing right now is to find an Achilles' heel for the disease. "
Researchers also gave updates on three trials that will test whether other kinds of immune therapy might prevent Alzheimer's. Unlike the Gammagard trials, they will involve people with no symptoms but who are likely to develop the disease because they carry a gene. Recent research in The New England Journal of Medicine shows the disease begins changing the brain 25 years before symptoms appear.
The results of several immune therapy trials expected this summer might be disappointing, because they started after symptoms appeared, says Bill Thies of the Alzheimer's Association.
Gammagard, made by Baxter International, is approved by the Food and Drug Administration for other diseases caused by immune disorders. Final results from the Alzheimer's testing, on 390 participants, are expected in January. Gammagard needs to be proved safe and effective before it can be recommended for Alzheimer's.
Even then, Relkin says, Gammagard is in limited supply because it is blood-based and expensive. Monthly doses cost $3,000 to $6,000, depending on a patient's body size. In the study, on 24 participants, those with the best outcomes got Gammagard every two weeks for 36 months. They had no decline at the end of the three years.
"Norm's study shows we're moving toward a paradigm shift in how we treat the disease," says Reisa Sperling, professor of neurology at Harvard Medical School.
The immune therapies all target amyloid plaques, clumps in the brain suspected of damaging and eventually killing neurons.
The government's timeline to find a prevention for Alzheimer's by 2025 might pan out, says Laurie Ryan of the National Institute on Aging: "We won't have a drug the next day for Alzheimer's, but it could be sooner than 10 years if one of these trials is successful."
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