(USA TODAY) -- Although it's still in a testing phase, the first long-term treatment shown to halt the progression of Alzheimer's disease is being hailed Tuesday by experts at the Alzheimer's Association International Conference 2012 in Vancouver.
The treatment is an immune therapy called IVIG/Gammagard that has been given intravenously for three years to a small group of participants. The findings on the treatment, made by Baxter International, follow a frustrating nine-year research period during which no new therapies have been discovered for the incurable brain-wasting disease affecting 5.4 million people in the United States.
The participants did not show improvement in most of the symptoms of Alzheimer's they already had, but nor did they show any further decline on measures of cognition, memory, daily functioning or mood over the three years.
Alzheimer's is a fatal illness that progresses slowly over years before wiping away personality, memory and cognition. No therapy on the market has stopped the deterioration caused by the disease.
"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. "The key thing right now is to find an Achilles' heel for the disease. The disease has to have a vulnerability."
In addition, researchers gave updates Tuesday on three trials that will test whether immune therapy might someday prevent the disease. Those trials will be done on participants who have no symptoms yet. Recent research done at the Washington University School of Medicine in St. Louis, Mo., published July 11 in the New England Journal of Medicine, shows the disease starts changing the brain 25 years before someone shows symptoms.
"I think the importance of our findings is to show there's still a lot of excitement about immune therapy,'' Relkin said.
Gammagard is already approved by the Food and Drug Administration for treating other diseases caused by immune disorders. It is made from plasma donated by healthy people and is rich in antibodies. It can have side effects, including transmitting viruses. Results from the final Alzheimer's testing, underway on 390 participants, are expected in January and need to show safe and effective treatment before the therapy can be recommended for Alzheimer's.
Even then, Relkin said, Gammagard is in limited supply because it is blood-based and expensive. Monthly doses range from $3,000 to $6,000, depending on the person's body size. In the study on 24 participants, five participants who were initially treated with a placebo and then switched to the Gammagard declined in health while on the placebo. They experienced less rapid decline while receiving a full dose of Gammagard.
The participants who had the best outcome received Gammagard every two weeks for 36 months. They had no decline at the end of the three years.
"I think what Norm's study shows is we're moving toward a paradigm shift in how we treat the disease," said Reisa Sperling, professor of neurology at Harvard Medical School. "I think ultimately we will find a way to treat and prevent the disease."
The ongoing and future trials using immune therapies work in different ways, but they all target amyloid plaques or clumps in the brain. Amyloid clumps are suspected of damaging and eventually killing neurons. Find a way to attack amyloid, these findings suggests, and you might have detected the Achilles' heel.
The Gammagard therapy appears to work in two ways, Relkins said. It neutralizes the potential damage of amyloid plaques and appears to halt the damage inflammation can cause.
But it doesn't remove plaque and make people better once their symptoms have progressed too far. The starting point for the three other trials discussed Tuesday is when people are presymptomatic. The participants in these three trials have a genetic mutation and will likely develop the disease eventually.
Those three trials are: the A4 Trial: Anti-Amyloid Treatment of Asymptomatic Alzheimer's Disease Cooperative Study (Harvard Medical School and Brigham andWomen's Hospital in Boston); the Dominantly Inherited Alzheimer Network - Therapeutic Trials Unit (the Washington University School of Medicine); and the Alzheimer's Prevention Initiative (Banner Alzheimer's Institute in Phoenix).
Bill Thies, chief medical and scientific officer for the Alzheimer's Association, said the results of several trials testing immune therapies on participants who were symptomatic when they started treatment are expected toward the end of the summer, but might be disappointing. He said some of the immune therapies target amyloid plaques just as statins target cholesterol forming lipids and help prevent heart disease. Statins were initially used only to treat people after they had heart attacks. Now, statins are among the most widely prescribed drugs in the world.
"There is a movement to treat people earlier for Alzheimer's,'' Thies said.
An ambitious new plan launched by the government in May calls for a prevention for Alzheimer's by 2025. That aggressive timeline might pan out, said Laurie Ryan.
"Given what we know now about the early changes in the brain 25 years out, we know therapy has to be administered early,'' said Ryan, program director for the Alzheimer's Disease Clinical Trials at the National Institute on Aging. "We're not going to have a drug the next day for Alzheimer's, but it could be sooner than 10 years if one of these trials gets approval from the FDA."