CYP3A4 and COVID-19: RTV is a CYP3A4 inhibitorand has been used together with PF-07321332 to treat COVID-19 patients.39 Without RTV, the half-life of WU-04 in human,mouse, and dog liver microsomes were between 0.9 to 2.3 min; in contrast,in the presence of RTV, the half-life was increased to more than 145min in human liver microsomes and 87.1 and 69.7 min in mouse and dogliver microsomes, respectively (Table S3).