Alzheimer's Vaccine Inching Toward Reality
Despite Setback, Vaccine for Alzheimer's Disease May One Day Be a Treatment Option
May 9, 2005 -- A to fight against the plaque-building protein implicated in may still be a viable option in the future for treating -- or perhaps even preventing -- the devastating disease, according to new research.
An earlier study of the experimental Alzheimer's vaccine was halted due to safety concerns in 2002 after 6% of the participants developed brain inflammation.
But two new studies that followed the participants suggest that the approach may slow the memory loss associated with Alzheimer's disease by reducing the buildup of beta-amyloid plaques in the brain.
"The idea of inducing the immune system to view beta-amyloid as a foreign protein, and to attack it, holds great promise," says researcher Sid Gilman, MD, a neurologist at the University of Michigan Health System, in a news release. "We now need to see whether we can create an immune response safely and in a way that slows the progression of Alzheimer's disease and preserves cognition."
Round 2 for Alzheimer's Vaccine
Although the safety phase of the study of the vaccine was halted in 2002, researchers continued to follow the participants, and their findings appear in two studies published in this month's issue of Neurology.
About 300 men and women with mild to moderate Alzheimer's disease received one to three injections of the vaccine before the study was stopped, and 72 received a placebo.
Brain scans using magnetic resonance imaging (MRI) to measure changes in brain volume were performed at the start of the study and again after 12 months or after early termination.
Researchers found that of those who received the vaccine, about 20% developed antibodies to beta-amyloid protein; that indicates the immune system of the participants had launched an attack against the plaque-causing protein in the injected vaccine. All but two of these 59 "immune responders" had received two doses of the vaccine.
These immune responders also experienced a decrease in brain volume, according to MRI scans. Researchers say this decrease may reflect a reduction in plaque buildup, but more study is needed to confirm this effect.