That's the conclusion of two new papers published in the journal Neurology by an international team of researchers who vaccinated hundreds of Alzheimer's disease patients with beta amyloid, a protein that builds up in Alzheimer's-affected brains.
The study was stopped early in 2002 after a few participants developed brain inflammation. But the researchers continued to monitor the patients for up to a year after their last injection. The new papers, including one led by the University of Michigan Health System neurologist who headed the study's safety committee, summarize the results of that effort.
Even as those results are published, doctors at U-M are preparing to recruit participants for a phase II clinical trial to test a new Alzheimer's immunotherapy vaccine strategy that has been through a phase I safety trial. The phase II study, which aims to stimulate an immune attack against beta amyloid without raising brain inflammation risk, is being conducted at 30 centers in the United States and dosing has already begun at some sites. All the trials have been funded by Elan Corporation and Wyeth Pharmaceuticals.
Results from the interrupted trial show that on the whole, study participants whose immune systems mounted a response against beta amyloid performed significantly better on a series of memory tests than those who received a placebo injection.
Brain scans also showed that patients who had an immune response experienced a decrease in brain size, possibly indicating the removal of built-up protein due to an immune system attack. A smaller group of immune responders also had a decrease in levels of a protein called tau in their spinal fluid, compared with participants who received placebo -- possibly in
Contact: Kara Gavin
University of Michigan Health System