Veterinary virologists find postinfection treatment for SARS-CoV-2Virologists at K-State say SARS-CoV-2-infected mice treated with a deuterated protease inhibitor show significantly increased survival July 8, 2021 K-State researchers Kyeong-Ok “KC” Chang (left) and Yunjeong Kim have published a new study about a successful postinfection for SARS-CoV-2, the virus that causes COVID-19.Photo courtesy K-State A successful postinfection treatment for SARS-CoV-2, the virus that causes COVID-19, may be close at hand. This is according to team of virologists at Kansas State University’s (K-State’s) College of Veterinary Medicine (CVM). Researchers Kyeong-Ok “KC” Chang, DVM, MS, PhD, and Yunjeong Kim, DVM, PhD, ACVM, have reported findings, showing mice infected with SARS-CoV-2 and then treated with a deuterated protease inhibitor have significantly increased survival and decreased lung viral load. The results suggest postinfection treatment with inhibitors of proteases essential for viral replication may be an effective treatment against SARS-CoV-2, K-State says. These protease inhibitors are a class of antiviral drugs that prevent viral replication by selectively binding to viral proteases and blocking the activation of proteins 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,” says Dr. Kim, an associate professor of diagnostic medicine and pathobiology at K-State. “After COVID-19 emerged, many research groups reported this inhibitor is also effective against the coronavirus that causes COVID-19, and many are currently pursuing the development of these protease inhibitors as a treatment.” Kim and Dr. Chang modified GC376 using a tool called deuteration to further increase the efficacy against SARS-CoV-2, K-State reports. Their work shows deuterated GC376 works better for SARS-CoV-2 in lab tests. “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,” says Chang, a professor of diagnostic medicine and pathobiology. “The results suggest deuterated GC376 has a potential for further development, and this deuteration method can be utilized to other antiviral compounds to generate more potent inhibitors.” The virologists are continuing to develop improved inhibitors using various methods, K-State reports. Deuterated GC376 is currently being evaluated for further potential development. The study, “Postinfection treatment with a protease inhibitor increases survival of mice with a fatal SARS-CoV-2 infection,” has been published in Proceedings of the National Academy of Sciences of the United States of America (PNAS). Access it here. Written with files from K-State.