Results from First Clinical Study Using Danoprevir to Treat Naive and Experienced COVID-19 Patients - The data from this small-sample clinical study showed that danoprevir combined with ritonavir is safe and well tolerated in all patients. After 4 to 12-day treatment of danoprevir combined with ritonavir, all eleven moderate COVID-19 patients enrolled, two naive and nine experienced, were discharged from the hospital as they met all four conditions as follows: (1) normal body temperature for at least 3 days; (2) significantly improved respiratory symptoms; (3) lung imaging shows obvious absorption and recovery of acute exudative lesion; and (4) two consecutive RT-PCR negative tests of SARS-CoV-2 nucleotide acid (respiratory track sampling with interval at least one day).