A Phase IIa Randomized, Open-Label Study of Telaprevir (VX-950) Administered Every 12 or Every 8 Hours in Combination With Either Peg-IFN alfa2a (Pegasys) and Ribavirin (Copegus) or Peg-IFN alfa2b (PegIntron) and Ribavirin (Rebetol) in Treatment-Naive Subjects With Chronic Genotype 1 Hepatitis C Infection

This is a Phase 2a, open-label (all people know the identity of the intervention), multicenter trial (conducted in more than one center) in participants with chronic genotype 1 HCV infection. The trial consists of a Screening phase of approximately 4 weeks, a treatment phase up to 48 weeks depending on participants' individual virologic response, and a follow-up phase of at least 24 weeks. All participants will receive 12 weeks of telaprevir treatment in combination with standard therapy. At Week 12, telaprevir dosing will end and participants will continue on standard therapy only. Participants will be randomly assigned to receive one of the two different dosage regimens of telaprevir (750 milligram \[mg\] every 8 hours (hr), or 1125 mg every 12 hr) in combination with standard therapy (pegylated interferon \[Peg-IFN\]-alfa-2a and ribavirin \[RBV\] or Peg-IFN-alfa-2b and RBV at the standard doses). Efficacy will be evaluated by HCV Ribonucleic Acid (RNA) values, viral response, viral breakthrough, partial response, early viral kinetics and sustained viral response. Pharmacokinetics, Pharmacokinetic-pharmacodynamic relationship will also be evaluated. Safety will be monitored throughout the study duration.