Among previously untreated patients who received three direct-acting antiviral agents ( with the ABT-@ / r dose administered as @ mg of ABT-@ and @ mg of ritonavir ) plus ribavirin , the rate of sustained virologic response at @ weeks after treatment was @ % among those who received the therapy for @ weeks and @ % among those who received the therapy for @ weeks ( difference , -@ percentage points ; @ % confidence interval , -@ to @ ; P = @ ) .