Two may be better than one drug to treat COVID-19, University of Maryland study finds

Drug combinations, rather than any single antiviral medication, may be the key to effective treatment of COVID-19, new research suggests.

The study found that when an experimental drug called brequinar was given with either of two medications that already had federal authorization — remdesivir or molnupiravir — it inhibited the growth of the virus in human lung cells and in mice.


The findings, published Feb. 7 in the journal Nature, will have to be checked in human trials. But researchers from the University of Maryland School of Medicine and the University of Pennsylvania Perelman School of Medicine found the mixtures to be far more potent and more likely to keep infections from becoming severe enough to require hospitalizations.

That could become more important if vaccines become less effective at preventing infections.


“As the virus continues to spread and mutate, we want drugs that are accessible, easy to administer, and effective against the current and future variants,” said Matthew Frieman, associate professor of microbiology and immunology at the University of Maryland, in a statement. He is a co-principal investigator on the study.

Researchers are increasingly reviewing approved drugs for new uses to reduce the time it takes to get therapies to patients. These researchers looked at 18,000 FDA-approved drugs to find ones that appeared to tackle COVID-19 in the lab. They used lung cells because they are a major target for the virus.

They found 122 candidates, including ones that already were being used to treat COVID-19: remdesivir, the first antiviral medication to get FDA approval, and molnupiravir, authorized in December. A third drug that appeared to stop viral spread in the body was brequinar, which is in clinical trials as a stand-alone COVID-19 treatment as well as part of a combination to treat cancer.

Researchers looked for help deciding on combinations from Frieman, a longtime coronavirus researcher whose lab has been studying therapies and vaccines against COVID-19. The team is testing other potential antivirals and looking at their effectiveness against the omicron variant that has caused a high number of infections in people who were vaccinated.

“Identifying combinations of antivirals is important, not only to increase the drugs’ potency against the coronavirus, but combining these drugs also reduces the risk of resistance,” said Sara Cherry, professor of pathology and laboratory medicine at the University of Pennsylvania and a co-principal investigator.