New Compounds May Lead to Treatments for Ebola, Marburg Viruses
There are currently no vaccines or effective treatments for the Ebola and Marburg filoviruses, two deadly viruses that cause hemorrhagic fever, but a new discovery by the US Army Medical Research Institute of Infectious Diseases (USAMRIID) and AVI BioPharma may lead to the first vaccines that can protect against the viruses which have a 90% fatality rate in humans.
PMO Compounds Block Virus Replication in Animal Studies
Researcher Travis K. Warren and colleagues discovered two compounds from a family known as antisense phosphorodiamidate morpholio oligomers, or PMO’s. These compounds block critical genetic viral sequences, halting virus replication long enough to give the host immune system time to defend against the virus and eliminate it from the body.
Nine monkeys were exposed to the Ebola virus and eight of them received a PMO compound called AVI-6002. The compound protected 60% of monkeys infected with the Ebola virus. In a second experiment, 3 of five monkeys in each group survived when given a dose of 40 mg of AVI-6002 per kilogram of body weight.
A second PMO compound called AVI-6003 protected 100% of monkeys infected with the Lake Victoria Marburg virus (MARV). It was also more than 90% effective in mice and guinea pigs.
Both compounds appeared to protect the animals when given up to one hour after exposure, suggesting they could also be used to treat people who accidentally become infected in labs and hospitals.
The Ebola and Marburg viruses are commonly transmitted through blood and bodily fluids. However, infection can also occur via the aerosol route, causing grave concern as potential weapons in biological warfare or terrorism.
The researchers have submitted investigational new drug applications (IND) for AVI-6002 and AVI-6003 to the US Food and Drug Administration (FDA) and are proceeding with clinical trials on a small group of human volunteers.
According to the United Nation’s World Health Organization (WHO), about 1850 cases of Ebola have occurred since 1976, leading to about 1200 deaths.
"Advanced antisense therapies for postexposure protection against lethal filovirus infections."
Travis K Warren, Kelly L Warfield, Jay Wells, Dana L Swenson, Kelly S Donner, Sean A Van Tongeren, Nicole L Garza, Lian Dong, Dan V Mourich, Stacy Crumley, Donald K Nichols, Patrick L Iversen & Sina Bavari. Nature Medicine, Published online: 22 August 2010. DOI:10.1038/nm.2202