A Prospective, Randomized, Open-label Study Evaluating the Viral Kinetics and Pharmacokinetics of Pegasys® Plus Copegus® and PEG-Intron® Plus Rebetol® in Interferon-naïve Patients With Chronic Hepatitis C.

Ribavirin

Peginterferon alfa-2a [Pegasys]

Peginterferon alfa-2b (PEG-Intron)

Ribavirin

Change From Baseline in Viral Load (log10 Reduction) at Week 12

Mean Change From Baseline in Viral Load (log10 Reduction) at Week 4 and Week 8

Weekly Viral Load Assessed at Drug Trough

The Area Under the HCV-RNA Curve Estimated From the Two Adjacent Pre-dose Assessments at Each Week

Mean Value of Area Under the HCV-RNA Curve Minus Baseline From Week 1 to Week 12

Cumulative Viral Absolute Area Under the HCV RNA Curve Minus Baseline Averaged Over the 12-week Period

Weekly Viral Absolute Area Under the HCV RNA Curve Estimated in the Frequent-sampling Cohort for Weeks 1 and 8

Percentage of Participants With a ≥ 2-log10 Decrease or Undetectable (< 60 International Units Per Milliliter) HCV RNA at Each Visit

Percentage of Participants With Undetectable HCV RNA (< 60 International Units/Milliliter) at Each Visit

Number of Participants With Marked Hematologic Abnormalities

Number of Participants With Marked Biochemical Test Abnormalities

Number of Participants With Marked Abnormalities in Thyroid Function Tests

Mean Trough Interferon Concentrations at Each Week

Area Under the Curve for Interferon in the Frequent-Sampling Cohort

Number of Participants With Adverse Events and Serious Adverse Events

Percentage of Participants With Each of the Identified HCV Quasispecies at Baseline and Weeks 1, 4, 8, and 12

Weekly AUC for IFN Concentrations for Pegasys and PEG-Intron Estimated by Population Pharmacokinetic Modeling