Ark Biopharmaceutical Co. Ltd.’s phase III testing its ziresovir in infants hospitalized with respiratory syncytial virus (RSV) infection produced positive top-line results, meeting both the primary endpoint of reduction in signs and symptoms (S&S) score (p=0.002) and a key secondary endpoint of reduction in viral load (p=0.006) compared with placebo. The company said it is the first oral RSV antiviral to be successful in phase III.