The study represents the first demonstration of complete protection against a lethal human infectious disease in nonhuman primates using RNAi, according to lead author Dr. Thomas W. Geisbert of the Boston University School of Medicine.
"We believe this work justifies the immediate development of Ebola SNALP as a countermeasure to treat Ebola infected patients, either in outbreaks or accidental laboratory exposures," he said.
Ebola virus causes hemorrhagic fever with case fatality rates as high as 80 percent in humans. The virus, which is infectious by aerosol (although more commonly spread through blood and bodily fluids of infected patients), is of concern both as a global health threat and a potential agent of biological warfare or terrorism.
Currently there are no available vaccines or therapies, so researchers working with Ebola virus must do so in maximum containment (Biosafety Level 4) laboratories. In these specially designed laboratories, investigators wear positive pressure "space suits" and breathe filtered air as they work, and all laboratory waste streams are sterilized.
The SNALP-RNAi therapeutic used in the study was developed by Tekmira Pharmaceuticals Corporation of Vancouver, BC. Previous research showed that these siRNAs completely protected guinea pigs when administered shortly after a lethal dose of ZEBOV was administered. While rodent studies are useful for screening prospective medical countermeasures, they are frequently not useful for prediction of efficacy in the more stringent non-human primate models.
Further studies in monkeys would be necessary to refine dosing, toxicology and other issued before the treatment could be licensed for human use.
"The significance of this report goes beyond the protection against Ebola virus," said COL John P. Skvorak, commander of USAMRIID. "It also represents the potential for this concept t
|Contact: Caree Vander Linden|
US Army Medical Research Institute of Infectious Diseases