A drug used to cure a deadly disease caused by a coronavirus in cats is expected to prove equally effective as a treatment for humans against COVID-19.

Researchers at the University of Alberta (Edmonton, Alberta, Canada) are now preparing to launch clinical trials of the drug which is a protease inhibitor that interferes with the virus’s ability to replicate, thus ending an infection. Proteases are key to many body functions and are common targets for drugs to treat everything from high blood pressure to cancer and HIV. First studied by the University of Alberta researchers following the 2003 outbreak of severe acute respiratory syndrome (SARS), the protease inhibitor was further developed by veterinary researchers who showed it cures a disease that is fatal in cats.

The team synthesized the compounds and tested them against the SARS-CoV-2 virus in test tubes and in human cell lines, revealing the crystal structure of the drug as it binds with the protein. The researchers determined the three-dimensional shape of the protease with the drug in the active site pocket, showing the mechanism of inhibition, which will allow them to develop even more effective drugs They plan to continue testing modifications of the inhibitor to make it an even better fit inside the virus, although the current drug shows enough antiviral action against SARS-CoV-2 to proceed immediately to clinical trials.

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“In just two months, our results have shown that the drug is effective at inhibiting viral replication in cells with SARS-CoV-2,” said Joanne Lemieux, a professor of biochemistry in the Faculty of Medicine & Dentistry. “This drug is very likely to work in humans, so we’re encouraged that it will be an effective antiviral treatment for COVID-19 patients.”