Researchers at Georgia State University have found that auranofin, a drug approved for rheumatoid arthritis, may be an effective treatment against the coronavirus.

The team set out to study how drugs already approved by the Food & Drug Administration interact with the virus, known among scientists as SARS-CoV-2.

“Drug repurposing is the fastest way to get a treatment for SARS-CoV-2, because it’s already been established that these medicines are safe to use in humans,” says Mukesh Kumar, lead author of the study, in a press release on GSU’s website. Kumar and his colleagues shared their work on bioRxiv for peer review.

Like all viruses, COVID-19 cannot self-reproduce. It needs host cells — animal or human — in order to make copies of itself.

“Effective drugs need to interfere with this replication process, shutting down the virus’ ability to proliferate inside the host,” says Hussin Rothan, a co-author of the study.

With auranofin, the coronavirus was cut down by 95% in human cells within 48 hours, and inflammation caused by the disease was significantly mitigated.

One of the primary causes of death in COVID-19 patients is a syndrome called a “cytokine storm,” wherein the body’s healing response to illness goes haywire, causing immune cells to attack healthy tissue, leading to organ failure. Cells treated with auranofin, however, saw a significant drop in cytokines, the proteins that signal immune cells to attack.

“This shows that the drug not only could inhibit replication of SARS-CoV-2, mitigating the infection, but also reduce the associated lung damage that often leads to severe respiratory distress and even death,” says Kumar.

Auranofin, including the brand-name drug Ridaura, was approved by the FDA in 1985. The drug is unique for being partially composed of gold particles, which have been used for centuries for their anti-inflammatory properties. Treatments involving gold compounds have also been considered for use against HIV, cancer, neurodegenerative disorders, and parasitic and bacterial infections.

The team at Georgia State University says they plan to continue their study on how auranofin impacts the coronavirus in animal models.