Merck & Co. has revealed the discovery of novel oral SARS-CoV-2 3C-like proteinase (3CLpro; Mpro) inhibitors for the potential treatment and/or prophylaxis of COVID-19. 3CLpro plays a key role in viral life cycle by cleaving viral protein and helps in replication and infection, which make 3CLpro a target for designing drugs to treat COVID-19.