A Study of Induction Dosing With Peginterferon Alfa-2a and Ribavirin in Participants With Chronic Hepatitis C (CHC) Genotype 1 Infection

Sustained virological response was calculated as the percentage of participants with undetectable (less than [<] 15 international units per milliliter [IU/mL]) hepatitis C virus (HCV) ribonucleic acid (RNA) as measured by the Roche TaqMan HCV Test 24 weeks after completion of the scheduled 48-week treatment period.

Virological response at the end of the scheduled treatment period was defined as the percentage of participants with undetectable (<15 IU/mL) HCV RNA as measured by the Roche TaqMan HCV Test at Week 48.

Virological response was defined as undetectable HCV RNA (<15 IU/mL) as measured by the Roche TaqMan HCV Test. Participants without HCV RNA measurements at a study week are considered non responders at that study week.

Relapse was determined based on virological response at the actual end of treatment and was calculated by dividing the number of participants who achieved a virological response at end of treatment but later had detectable HCV RNA at the last assessment post-treatment by the number of participants with a virological response at end of treatment, defined as undetectable HCV RNA (<15 IU/mL). Participants who achieved a virological response at end of treatment but did not have any HCV RNA assessment during follow-up were excluded and were not considered as having relapsed. However, if no assessment was available within the end of-treatment time window but the participant had a sustained virological response according to the actual treatment period, backward imputation was used and the participant was considered to have achieved an end-of-treatment virological response in the analysis.

The ability of virological responses to predict sustained virological response according to the scheduled treatment periods was assessed in terms of positive predictive value (PPV) and negative predictive value (NPV). The PPV indicates probability of achievement of viral suppression (undetectable HCV RNA) for achieving a sustained virological response and the NPV indicates probability of not achieving viral suppression for not achieving a sustained virological response. The PPV at Week 4 or 12 was calculated as the number of participants who achieved viral suppression both at Week 4 or 12 and at Week 72 divided by the number of participants who achieved viral suppression at Week 4 or 12, multiplied by 100. The NPV at Week 4 or 12 was calculated as the number of participants who failed to achieve viral suppression at Week 4 or 12 and at Week 72 divided by the number of participants who failed to achieve viral suppression at Week 4 or 12, multiplied by 100.

The mean decrease in log10 HCV RNA levels from baseline was assessed in both the induction group and the standard group.