In this multicenter , randomized , double-blind , placebo-controlled trial , we assigned previously untreated patients with HCV genotype 1 infection , in a 3:1 ratio , to an active regimen consisting of a single-tablet coformulation of ABT-450 / r-ombitasvir ( at a once-daily dose of 150 mg of ABT-450 , 100 mg of ritonavir , and 25 mg of ombitasvir ) , and dasabuvir ( 250 mg twice daily ) with ribavirin ( in doses determined according to body weight ) ( group A ) or matching placebos ( group B ) .