Treatment with antibodies naturally produced in the body appears to halt the memory-robbing progression of Alzheimer's disease, according to promising early research that scientists plan to expand over the next year.
Current Alzheimer's drugs provide moderate relief to some patients but do not stop the disease from advancing. By contrast, the antibodies - a treatment already in use for multiple sclerosis and other autoimmune diseases - stopped or slightly reversed the disease in six of eight patients participating in an 18-month preliminary clinical trial.
Scientists from Weill Cornell Medical School in New York reported the findings at the 10th International Conference on Alzheimer's Disease and Related Disorders in Madrid, Spain. The findings are similar to those from an earlier German study of five patients over six months.
"Those people are not just stabilizing; many of them are getting better. That's quite remarkable," said William Thies, vice president for medical and scientific relations of the Chicago-based Alzheimer's Association.
On the basis of these early results, a larger Phase 2 trial with 24 patients has already begun that will compare the antibody treatment to an inert placebo, and a Phase 3 multicenter trial with 210 patients will start next year.
"We're using something which the human body potentially evolved on its own to deal with this disease," said Cornell's Dr. Norman Relkin, also of the New York Presbyterian Hospital, who presented the trial results in Madrid.
Experts say the need for new drugs is critical because the disease affects an estimated 4.5 million Americans and the number may accelerate as a result of new evidence linking type-2 diabetes with an increased risk of Alzheimer's disease. The cost of the disease in the United States is estimated to be $100 billion annually. Diabetes, which is associated with obesity, has reached epidemic proportions in America, affecting an estimated 73 million people.
The patients in the new studies were treated with a product called intravenous immunoglobulin, or IVIg, a concoction of many antibodies collected from blood donated by healthy volunteers. The Food and Drug Administration approved immunoglobulin therapy more than 25 years ago for treating autoimmune diseases.
A single IVIg dose requires the pooled blood of several thousand donors and costs about $3,000. Baxter International Inc. in suburban Deerfield, Ill., produces IVIg and is funding the clinical trials.
Certain immune-system cells circulating in the blood make thousands of different antibodies against germs and other foreign invaders. They also make antibodies to get rid of rogue proteins, which occur as a result of cellular damage or aging.
One of these proteins, beta amyloid, is widely thought to cause the destruction of brain cells that leads to memory loss. Some people are better able to make antibodies against the various forms of beta amyloid, and population studies show they have a lower rate of Alzheimer's disease. People who have low levels of beta amyloid antibodies, meanwhile, are at higher risk for Alzheimer's.
The Cornell researchers believe IVIg works against Alzheimer's because it contains antibodies that neutralize beta amyloid and speeds its elimination from the body.
"We have found that there are multiple types of antibodies against the amyloid molecule in IVIg, some targeting the end of the amyloid molecule and some the middle," Relkin said.
Steve Snyder, the National Institute on Aging's program director for the etiology of Alzheimer's disease, said the IVIg research "certainly does look promising from very early pilot data. There is some improvement in cognition in these patients. That goes hand in hand with what we see in the animal studies."
Ronald Kotulak writes for the Chicago Tribune.