Alzheimer's Drug Shows Early Promise
By Amanda Gardner
30 june 2008---- Long-anticipated results from a trial on an experimental Alzheimer's therapy look promising, at least in a certain group of patients.
Findings that are slated to be presented Sunday at the International Conference on Alzheimer's Disease in Chicago suggest that while the drug, bapineuzumab, showed only a modest trend towards a benefit in patients with the ApoE4 gene, there were more notable improvements in the degree of cognitive decline in individuals lacking the gene.
Patients who lack the ApoE4 gene have a predisposition to developing Alzheimer's, especially earlier in life.
"This is the first study of adequate size and duration that suggests the immunotherapy beta-amyloid model works," said Dr. Anton Porsteinsson, an associate professor of psychiatry at the University of Rochester School of Medicine who was one of the investigators for the study. "Immunotherapy is a huge front in the development of treatments."
Many experts are hoping the results will usher in a new era in Alzheimer's treatment and research. "If it had failed, it would have significant reverberations," Porsteinsson. "It allows this and multiple other studies to move forward. It's a big relief, but it also turns into considerable excitement."
"The recently announced bapineuzumab results were encouraging enough to keep moving forward, but yet not definitive enough to be certain of any effect," added Dr. Sam Gandy, chairman of the Alzheimer's Association National Medical and Scientific Advisory Council and an Alzheimer's expert with Mount Sinai in New York City. " The best care for any Alzheimer's patient is in the setting of a clinical trial, if possible, with bapineuzumab or any of a number of agents. Our most promising drugs are in trials and not yet approved."
Gandy serves as a safety monitor on another Wyeth/Elan vaccine trial. Wyeth and Elan also sponsored the current trial.
Immunotherapy, an emerging frontier for a variety of different diseases, involves stimulating the body's own immune system to fight various conditions, including cancer.
Porsteinsson estimated that some one-half to two-thirds of the research push in Alzheimer's is aimed at amyloid therapy and especially immunotherapy.
Bapineuzumab is a humanized monoclonal antibody which binds to and might be able to eliminate beta amyloid peptide, which accumulate as plaques in the brains of people with Alzheimer's. The drug delivers antibodies to beta amyloid.
Most experts in the field of Alzheimer's believe that the build-up of beta-amyloid proteins in the brain are responsible for the disease.
But clinical gains in the area of Alzheimer's, not to mention advancement in a basic understanding of the disease, have been hard to come by.
This phase 2 trial involved both men and women with mild to moderate Alzheimer's at more than 30 sites in the United States, Finland and the United Kingdom. All participants received bapineuzumab.
Researchers noted statistically significant improvements in patients without the ApoE4 gene. The therapy did not appear to have a statistically significant benefit in patients with the gene, although there was some benefit.
A large, phase 3 study is currently underway, although even if all goes well, the drug could take almost four years to reach the market, Porsteinsson said.