Patients receiving once-daily 800mg of IDX899 achieved a mean and median plasma viral load reduction of 2.01 and 2.11 log(10), respectively, after seven days of treatment. Six out of eight patients achieved a 2 log(10) or greater reduction in viral load with one patient achieving undetectable virus levels (< 50 copies/mL). No serious adverse events were reported in this cohort and no patients discontinued the study. Given the potent antiviral activity and favorable preliminary safety demonstrated at 800mg once-daily, we will explore sequential cohorts of 400mg once-daily followed by 200mg once-daily.