Scientists have identified a post-infection treatment for SARS-CoV-2, the virus that causes COVID-19, and successfully demonstrated its efficacy in stopping viral reproduction in mice.
The study, published in the journal Proceedings of the National Academy of Sciences, shows that animal models infected with SARS-CoV-2 and treated with an inhibitor of protease enzymes had significantly increased survival and decreased lung viral quantity.
These protease inhibitors are a class of antiviral drugs that prevent viral reproduction by selectively binding to viral enzymes and blocking the activation of proteins that are necessary for the production of infectious viral particles.
"We developed the protease inhibitor GC376 for treating a fatal coronavirus infection in cats, which is now under commercial development as an investigational new animal drug," said Yunjeong Kim, associate professor at Kansas State University in the US.
"After COVID-19 emerged, many research groups reported that this inhibitor is also effective against the coronavirus that causes COVID-19, and many are currently pursuing the development of protease inhibitors as a treatment," Yunjeong Kim said.
The research team modified GC376 using a tool called deuteration to test its efficacy against SARS-CoV-2.
Treatment with a deuterated variant starting at 24 hours post-infection resulted in significantly increased survival of mice compared to untreated mice, the researchers said.
The results suggest that deuterated variants have excellent potential as antiviral agents against SARS-CoV-2, they said.
"Treating SARS-CoV-2-infected mice with deuterated GC376 significantly improved survival, viral replication in lungs, and weight losses, which shows the efficacy of the antiviral compound," said Kyeong-Ok Chang, professor at Kansas State University.
"The results suggest deuterated GC376 has a potential for further development, and this deuteration method can be utilised to other antiviral compounds to generate potent inhibitors," Kyeong-Ok Chang said.
The virologists are continuing to develop improved inhibitors using various methods. Deuterated GC376 is currently being evaluated for further potential development.