Antiviral drug for cats may help fight Covid-19 in humans

Researchers are preparing to launch clinical trials of a drug used to cure a deadly disease caused by coronavirus in cats that they expect will be effective as a treatment for humans against Covid-19.

“In just two months, our results have shown that the drug is effective at inhibiting viral replication in cells with SARS-CoV-2,” said a study researcher Joanne Lemieux from the University of Alberta (UA) in Canada.”

“This drug is likely to work in humans so we’re encouraged that it will be an effective antiviral treatment for Covid-19 patients,” Lemieux added.

The drug is a protease inhibitor that interferes with the virus’s ability to replicate, thus ending an infection, the study published in the journal Nature Communications reported.

Proteases were key to many body functions and were common targets for drugs to treat everything from high blood pressure to cancer and HIV. First studied by UA’s John Vederas and Michael James following the 2003 outbreak of severe acute respiratory syndrome (SARS), the protease inhibitor was further developed by veterinary researchers who showed it cured a disease that is fatal in cats. The researchers explained that Vederas synthesized the compounds and researcher Lorne Tyrrell tested them against the SARS-CoV-2 virus in test tubes and human cell lines.

The research team then revealed the crystal structure of the drug as it binds with the protein. “We determined the three-dimensional shape of the protease with the drug in the active site pocket showing the mechanism of inhibition. This allows us to develop even more effective drugs,” Lemieux said.

She will continue to test modifications of the inhibitor to make it a better fit inside the virus, Lemieux added. But she said the current drug shows enough antiviral action against SARS-CoV-2 to proceed immediately to clinical trials.

“Typically for a drug to go into clinical trials, it has to be confirmed in the lab and then tested in animal models,” Lemieux said.

“Because this drug has already been used to treat cats with coronavirus and it’s effective with little to no toxicity, it’s already passed those stages and this allows us to move forward,” she added.

The researchers have established a collaboration with Anivive Life Sciences, a veterinary medicine company that is developing the drug for cats to produce the quality and quantity of drug needed for human clinical trials. The team said it will likely be tested in Alberta in combination with other promising antivirals such as remdesivir.