SAN DIEGO, Oct. 9 (UPI) -- An experimental compound that blocks the ability of the Ebola virus to replicate in the body successfully prevented rhesus monkeys from succumbing to it, according to a new study.
A clinical trial of the compound, GS-5374, is currently being conducted by the company Gilead Sciences, which worked with the United States Army Medical Research Institute of Infectious Diseases, or USAMRIID, to develop it.
GS-5374 was also effective in the lab against Middle East Respiratory Syndrome, or MERS, Marburg virus, and several variants of Ebola virus -- including the strain responsible for the current outbreak in West Africa that started in 2013.
"The compound, which is a novel nucleotide analog prodrug, works by blocking the viral RNA replication process," said Dr. Travis Warren, a principal investigator at the USAMRIID, in a press release. "If the virus can't make copies of itself, the body's immune system has time to take over and fight off the infection."
Researchers in the new study, which is to be presented at the annual conference of the Infectious Diseases Society of America, first tested GS-5734 in the lab with filovirus-infected human endothelial cells, liver cells, and macrophages, finding it was successful against the virus.
The researchers then tested the compound in Ebola-infected rhesus monkeys, finding 100 percent of those treated within three days of infection survived and experienced a reduction in the symptoms of the virus.
A clinical trial is being conducted with healthy human volunteers. Gilead, however, is exploring the use of the animal efficacy rule, a U.S. Food and Drug Administration regulation that allows qualifying drug studies with animals to be approved when testing with humans is not feasible or ethical.
"This is the first example of a small molecule -- which can be easily prepared and made on a large scale -- that shows substantive post-exposure protection against Ebola virus in nonhuman primates," said Dr. Sina Bavari, science director for the USAMRIID. "In addition to 100 percent survival in treated animals, the profound suppression of viral replication greatly reduced the severe clinical signs of disease."