Drug to defeat feared bioterror virus

PARIS: An experimental drug tested on lab animals has shown remarkable success in tackling two viruses, including a close cousin to a feared bioterror pathogen, a study said.

The drug, bavituximab, takes a novel tack in confronting viruses, which are notorious for mutations that evade or resist conventional pharmaceutical molecules. Instead of confronting the intruder head-on, bavituximab waits until the virus has infected the cell.

At that point, a fatty molecule called phosphatidylserine, which is normally positioned on the cell wall’s internal surface, flips to the outside of the cell.

Bavituximab then latches onto the phosphatidylserine, sending a red flag to the body’s immune system to dispatch white blood cells to destroy the infected cell. In a study in Nature Medicine, bavituximab was put through its paces among guinea pigs infected with Pichinde virus — a close relative of the Lassa fever virus, considered a potential bioterror weapon by the Pentagon.

Animals that had not been inoculated with bavituximab were all killed; those who had received the injection had a 50% survival rate. By giving the bavituximab group an additional injection with a standard anti-virus drug called ribavirin, the survival rate rose to 63%. The drug also provided 100% protection amongst mice exposed to a virus called cytomegalovirus, whereas only 25% of untreated animals survived.

Co-author Philip Thorpe, a professor of pharmacology at UT Southwestern Medical Center in Texas, said the findings were exciting, for they raised the prospect of a “completely new class” of anti-viral drugs that may also sidestep the problem of mutation. “By targeting a property of the host cell rather than the virus itself, anti-PS [phosphatidylserine] antibodies have the potential to treat a range of viral infections,” he said.