Hepatitis C Virus ribonucleic acid (HCV-RNA) levels in plasma were measured using the Roche COBAS®AmpliPrep/COBAS® TaqMan® HCV Test, v2.0 on blood samples drawn from each participant. SVR12 was defined as HCV RNA below the lower limit of quantification (\<LLOQ) at 12 weeks after the end of all study therapy. The primary efficacy hypothesis for this study was that the percentage of participants achieving SVR12 in the grazoprevir plus elbasvir arm was non-inferior to the percentage in the SOF plus PR arm. A secondary statistical analysis was performed to determine whether the percentage of participants achieving SVR12 in the grazoprevir plus elbasvir arm was superior to the percentage in the SOF plus PR arm.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that was temporally associated with the use of the Sponsor's product, was also an AE. The percentage of participants who experienced at least one AE was reported for each treatment arm.

An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a preexisting condition that was temporally associated with the use of the Sponsor's product, was also an AE. The percentage of participants who discontinued study treatment due to an AE was reported for each treatment arm. Participants that discontinued study drug treatment due to an AE may have still continued on trial.