Abstract 1217 SARS-CoV-2 Main Protease Inhibitor High-Throughput Screen

Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2, SARS2) is responsible for the first global pandemic of the 21st century, and infections continue to affect the lives of millions of people each day. The SARS2 main protease enzyme (Mpro) is considered an excellent drug target due to conservation across this virus family and dissimilarity to human proteases. However, the first clinical drug for Mpro, Paxlovid (active component - Nirmatrelvir), is potentially susceptible to resistance mutations. In an effort to develop inhibitors that are less susceptible to resistance, our team has created a robust cell-based assay for Mpro activity and used it in a primary high throughput screen of a library of 649,568 compounds. This primary screen identified 8,777 candidate inhibitors (1.35% hit rate). A secondary biochemical screen was used to pick out potential direct binders and activity inhibitors. This strategy resulted in several dozen dose-responsive inhibitors including a few previously reported compounds such as Calpain inhibitor II. This presentation will discuss the screening assays, approaches, and the mechanisms of action of select inhibitors. This work was supported by the National Institute of Allergy and Infectious Diseases [1U19AI171954-01].