Among patients with genotype 1 , a sustained virologic response was reported in 96.4 % ( 95 % confidence interval [ CI ] , 89.8 to 99.2 ) who were treated for 12 weeks and in 75.6 % ( 95 % CI , 59.7 to 87.6 ) who were treated for 8 weeks among previously untreated patients and in 97.7 % ( 95 % CI , 88.0 to 99.9 ) who were treated for 12 weeks among previously treated patients .