Hope for Mad Cow Disease
"Both drugs have a very long history of clinical use," May says. "Exactly how they work is unclear, but we're trying to figure it out."
Although it's a long leap from the test tube to the human brain, the drugs are relatively safe and the diseases are always fatal, so Prusiner's group feels there's not much to lose.
Without doing extensive studies in animals, it is far too soon to make predictions about how effective these drugs will work in humans, Hermann Schätzl, MD, tells WebMD. He is a prion researcher at the Max von Pettenkofer-Institute of the Gene Center in Munich, Germany.
As several years elapse before symptoms appear in prion infection, drugs given during this period might prevent irreversible brain damage.
"If tests were available to determine who was infected, we could say, 'You have tested positive, but something can be done,'" says Michael B. Coulthart, who says it may be acceptable to use such drugs in patients already affected by prion diseases, or perhaps in healthy people who have the inherited form of the disease but are not yet ill. Coulthart, who reviewed the study for WebMD, is chief of host genetics and prion diseases of the National Microbiology Laboratory, Health Canada, in Winnipeg.
The researchers at University of California at San Francisco are developing a formal clinical trial of these drugs in late-stage Creutzfeldt-Jakob and other prion diseases and hope to begin enrolling patients later this year.
"Since we already know a lot about how chlorpromazine and quinacrine work, our understanding of the mechanisms of the prion diseases and how the drugs act will accelerate, even if the results of the clinical trials turn out to be negative," Magnus Sjogren, MD, PhD tells WebMD. Sjogren, who was not involved in the study, is a clinical neuroscientist at Gothenburg University in Sweden.
This research might also offer insight into other neurological disease like Alzheimer's, Huntington's, and Parkinson's diseases, says Prusiner.
With Reporting From David Flegel, MS