The drug baricitinib, branded as Olumiant, cut the median recovery time by about a day when added to remdesivir, compared to patients treated with the antiviral alone, Lilly said.
Remdesivir was granted an emergency use authorization (EUA) in May after trial data showed it helped shorten hospital recovery time by 31%.
Lilly said it plans to discuss the potential for an EAU for baricitinib with the U.S. Food and Drug Administration, based on the results from the trial, which tested more than 1,000 patients.
"As an already approved and available drug, we believe baricitinib could serve as an important additional treatment option as the medical community continues to learn how to best manage patients hospitalized with COVID-19," said Mizuho analyst Vamil Divan.
The drug, licensed by Lilly from Incyte Corp, could help suppress a potentially lethal immune response to COVID-19 called "cytokine storm".
U.S. hospitals have turned down about a third of their allocated supplies of remdesivir since July as need for the costly drug wanes, the Department of Health and Human Services (HHS) confirmed on Friday.
Remdesivir costs $3,120 for a six-vial course.
Eli Lilly in June also began a late-stage study to test baricitinib as a monotherapy in hospitalized patients across the United States, Europe, Asia and Latin America.
By Manas Mishra