This is a randomized (study medication assigned by chance), 5-arm, double-blind (neither investigator nor the participant knows the treatment that the participant receives), placebo-controlled (an inactive substance that is compared with the study medication to test whether the study medication has a real effect in clinical study) study to compare the efficacy, tolerability and safety of different TMC435 regimens combined with peginterferon alfa-2a (PegIFNα-2a) and ribavirin (RBV) versus PegIFNα-2a plus RBV alone in adult treatment-naive patients with chronic genotype 1 HCV infection. The study mainly consists of 3 phases: screening phase (approximately 6 weeks), treatment phase (up to 48 weeks), and follow up phase (up to 48 weeks). In the treatment phase, patients will be divided in to 5 different arms in a 1:1:1:1:1 randomized ratio. In treatment arms 1 and 2, patients will receive 12 weeks of therapy with TMC435 along with PegIFNα 2a and RBV followed by treatment with PegIFNα 2a, RBV, and TMC435-matched placebo. In treatment arms 3 and 4, patients will receive 24 weeks of therapy with TMC435, PegIFNα 2a, and RBV. In treatment arm 5 (control group), patients will receive PegIFNα 2a and RBV for 48 weeks and TMC435 matched placebo for the first 24 weeks. Collection of blood samples for efficacy evaluations will be done at scheduled visits throughout the study. Safety evaluations for adverse events, clinical laboratory tests, physical examination, vital signs and electrocardiogram will be monitored throughout the study. The total duration of the study will be up to approximately 72 weeks after initiation of treatment.
