Discovery of Potent and Broad-Spectrum Pyrazolopyridine-Containing Antivirals against Enteroviruses D68, A71, and Coxsackievirus B3 by Targeting the Viral 2C Protein.

The enterovirus genus of the picornavirus family contains many important human pathogens. EV-D68 primarily infects children, and the disease manifestations range from respiratory illnesses to neurological complications such as acute flaccid myelitis (AFM). EV-A71 is a major pathogen for the hand, foot, and mouth disease (HFMD) in children and can also lead to AFM and death in severe cases. CVB3 infection can cause cardiac arrhythmias, acute heart failure, as well as type 1 diabetes. There is currently no FDA-approved antiviral for any of these enteroviruses. In this study, we report our discovery and development of pyrazolopyridine-containing small molecules with potent and broad-spectrum antiviral activity against multiple strains of EV-D68, EV-A71, and CVB3. Serial viral passage experiments, coupled with reverse genetics and thermal shift binding assays, suggested that these molecules target the viral protein 2C. Overall, the pyrazolopyridine inhibitors represent a promising class of candidates for the urgently needed nonpolio enterovirus antivirals.