Identification of a Potent Pan-Coronaviral Main Protease Inhibitor.

The global impact of SARS-CoV-2 and the continued emergence of zoonotic coronaviruses underscore the urgent need for broad-spectrum antivirals for pandemic preparedness. Herein, we report AVI8122, a covalent pan-coronaviral inhibitor that targets 19 Mpros across the α, β, γ, and δ genera, encompassing bat, human, and other animal coronaviruses. AVI8122 exhibits low nanomolar potency and favorable pharmacokinetics in mice. Structural studies reveal that AVI8122 forms a covalent bond with the catalytic cysteine and maintains conserved interactions within the active sites of these Mpros. In cellulo, AVI8122 efficiently inhibited the replication of SARS-CoV-2 and its variants of concern as well as the activity of Mpros from all four genera. Furthermore, in mouse models, AVI8122 conferred dose-dependent protection against a lethal SARS-CoV-2 infection. Our findings position AVI8122 as an early lead compound and a tractable structural starting point for the development of broad-spectrum antivirals against future coronavirus spillover threats.