The Clinical Study NCT02041715 was abandoned in West Africa shortly before the outbreak of the Ebola fever in the area.

After Dr. MacLachlan’s call to Dr. Geisbert, now a professor at the University of Texas Medical Branch at Galveston, TKM-Ebola was tested on rhesus macaques at the U.S. Army Medical Research Institute of Infectious Diseases biosafety level 4 containment lab in Maryland.

All four macaques challenged with lethal doses of the Ebola virus, then treated for seven days with TKM-Ebola, survived. (In another arm of the study, one of three macaques given four doses, instead of seven, died.)

The results, published in The Lancet in 2010, were encouraging enough to persuade the U.S. Department of Defence’s biomedical research arm to sign a $140-million contract with Tekmira. A phase I clinical trial, designed to test the safety of the treatment in 28 healthy volunteers, began in January, and the U.S. Food and Drug Administration granted the drug fast-track approval in March.

But Tekmira announced in July that the trial had hit a road block: The FDA asked the company to halt the trial until it could provide more data to ensure the safety of the healthy volunteers, some of whom were being dosed with as much TKM-Ebola as would be given to a lethally infected patient. The hold was partly lifted in August, allowing Tekmira to offer the drug on an emergency basis to Ebola patients, but the trial itself is still on hiatus.