Bavituximab, an anti-viral drug developed by UT Southwestern Medical Center researchers, shows promise as a new strategy to fight viral diseases, including potential bioterrorism agents.
In a study appearing in the December issue of Nature Medicine , groups of guinea pigs infected with a virus similar to Lassa fever virus recovered from the fatal disease when treated with bavituximab alone or in combination with a common anti-viral medication. Bavituximab treatment also cured mice infected with cytomegalovirus, an opportunistic infection that afflicts transplant and AIDS patients.
Dr. Philip Thorpe, professor of pharmacology at UT Southwestern and senior author of the study, proposed that phosphatidylserine, a lipid molecule that is normally positioned on the internal surface of a cell, flips to the outside of the cell when the cell is infected by a virus. His laboratory developed bavituximab, which binds to phosphatidylserine on the infected cells. Dr. Thorpe, holder of the Serena S. Simmons Distinguished Chair in Cancer Immunopharmacology, predicted that this interaction would muster the body's immune cells to attack and destroy the infected cells before the virus has a chance to replicate.
Drs. Philip Thorpe, professor of pharmacology, and Melina Soares, instructor of pharmacology, have shown that an anti-viral drug developed at UT Southwestern shows promise as a new strategy to fight viral diseases.
"When injected into the bloodstream, bavituximab circulates in the body until it finds these inside-out lipids and then binds to them," said Dr. Thorpe. "In the case of virus infection, the binding raises a red flag to the body's immune system, forcing the deployment of defensive white blood cells to attack the infected cells."
In the study, half of the guinea pigs infected with a virus similar to the Lassa fever virus were cured when bavituximab was administered alone. This is the first report of a therapeutic treatment being effective against advanced Lassa-like fever infections in animals. Lassa fever is an endemic disease in portions of West Africa, where the Lassa virus is carried by rats. As a hemorrhagic fever virus, Lassa is listed as a Category A bioterrorism agent - the same class as the Ebola and Marburg viruses - by the Centers for Disease Control and Prevention.
In a second experiment, researchers administered both bavituximab and the anti-viral medication ribavirin. Ribavirin works by a different mechanism than bavituximab; it stops virus replication in the cell. With this combination therapy, 63 percent of guinea pigs survived.