April 3, 2007
Researchers in Japan report that an experimental vaccine for Alzheimer's disease proved safe and effective in mice. Years more study and testing will be required to see if the vaccine proves safe and effective in people as well. But, the new research offers a glimmer of hope that an Alzheimer's vaccine may one day help prevent or stop the downward progression of mental decline for an illness that afflicts more than five million Americans, and many more worldwide.
The vaccine, given by mouth, stimulates the immune system to attack beta amyloid, the toxic substance that builds up in the brains of those with Alzheimer's. When given to the mice, which had been specially bred to develop an ailment that resembles Alzheimer's in people, the animals had fewer plaques in the brain and also performed better in mazes and other memory tests.
It is important to note, however, that what works as a vaccine in mice may very well not work in humans. This is especially true of older people, who have much weaker immune systems compared to young people.
Vaccine Promise Researchers are excited by the prospect of an effective Alzheimer's vaccine because it could be given to people at high risk for the disease to fend off future mental decline. It could also have benefits for those afflicted with the illness, particularly those in the earlier stages of disease, helping to prevent further memory loss and even restore thinking abilities.
A promising vaccine had reached advanced testing stages in people several years ago. However, it had to be pulled after it caused brain inflammation in some of those being tested. Interestingly, a group of 20 people with Alzheimer's who received this vaccine and who developed antibodies against beta-amyloid have been followed for the last three years. None have gotten worse, though none have improved. The drug makers Wyeth and Elan, which created that vaccine, have since modified it to make it safer, and are testing it again.
Numerous additional vaccines are in various stages of testing and development, including some in early-phase trials outside the U.S. (www.clinicaltrials.gov). It will be several years before the safety and effectiveness of these newer vaccines will be known.
The Fisher Center for Alzheimer's Research Foundation continues to fund essential basic research into the underlying cases of Alzheimer's disease, research that may one day prove key to finding a cure for the disabling illness. For more on vaccines and medicines currently under development for Alzheimer's disease, visit www.ALZinfo.org.
Brain Research, March 2007. U.S. National Institutes of Health, www.clinicaltrials.gov.