Remdesivir has been cleared for emergency use in severely-ill patients in the United States, India and South Korea. Some European nations are also using it under compassionate programs.
Trials of the drug in humans are ongoing, and early data has shown the drug helped patients recover more quickly from the illness caused by the new coronavirus.
In the study, 12 monkeys were deliberately infected with the coronavirus, and half of them were given early treatment with remdesivir.
Macaques that received remdesivir did not show signs of respiratory disease and had reduced damage to the lungs, according to the study authors.