An Open Label, Randomized, Parallel Design Estimation Pilot Study to Compare the Effectiveness of 36 vs 48 Wks PegIntron Plus Ribavirin Treatment for HCV Patients Without Rapid Virologic Response(RVR) But With Undetectable HCV RNA at wk 8

Purpose: To compare the effectiveness of 36 wks versus 48 wks pegintron plus ribavirin treatment for HCV patients without RVR, but with undetectable HCV RNA at wk 8. Study Design: This is a multi-site, prospective, open label, randomized, pilot trial. Approximately 60 HCV Genotype 1 patients who fail to achieve RVR at wk 4 but achieve undetectable HCV RNA at wk 8 (<50 IU/ml) will be recruited into 2 arms(30 in each arm). Patients must receive pegylated IFN-α2b at 1.5 μg/kg of body weight/week and ribavirin 800~1400 mg/day for 12 wks before entering this study. Study Duration: The estimated recruitment period is 12 months; the follow-up duration is 72 weeks (longest treatment period plus 6 month- f/u period); the total study duration (FPE->LPLV) is estimated to be 2.5 years Statistical Analysis and Sample Size Justification: A. The study is not primarily designed for hypothesis testing; thus the sample size calculation is not based on the primary objective, Approximately 60 subjects (30 in each arm) will be recruited into this study B. For descriptive statistics, the continuous variables will be expressed as mean ± standard deviation, and the categorical variables will be performed the number of cases and the corresponding percentages. The primary analysis will focus on the efficacy response to the shortened HCV treatment course (36 wks) compared with standard course (48 wks). The between-group difference for efficacy endpoint will be assessed by the difference in the percentage of virologic responder after 24 wks of HCV treatment. For univariate analyses, comparisons of independent samples (shortened vs. standard course) will be assessed with Student's t test. The comparisons of categorical variables will be assessed using the chi-square test. Regarding the multivariate analysis, the proportion of patients achieving virologic responder will be compared among groups using a logistic regression analysis with terms of potential confounding factors. The OR estimates will be derived from the logistic regression model and the corresponding 95% CIs will be used to quantify the each effect of treatment course length and confounding factors. All randomized patients who take at least one dose of HCV regimen will be included in safety assessment. Fisher's exact test will be used to compare between-group incidences of AEs. For patients with any clinical AEs, treatment related AEs, serious AEs, or discontinuations because of AEs, the data among groups will be provided as well. Statistical significance will be determined at the 0.05 level for all tests.