Aim: This study was conducted to clarify the factors related to sustained virological response (SVR) to pegylated interferon alpha 2b (PEG-IFN) plus ribavirin (RBV) combination therapy administered for 48 weeks in patients with chronic hepatitis C virus (CHCV) and to evaluate the usefulness of prolonged treatment in patients with late virological response (LVR).
Methods: Of 2257 patients registered at 68 institutions, those with genotype 1 and high viral load were selected to participate in two studies. Study 1 (standard 48-week group, n = 1480) investigated SVR-determining factors in patients who received the treatment for </=52 weeks, whereas study 2 compared SVR rates between patients with LVR who received treatment for either 36-52 weeks (48-week group, n = 223) or 60-76 weeks (72-week group, n = 73).
Results: In study 1, SVR rate was 44.9%; that in male subjects (50.4%) was significantly (P < 0.0001) higher than in female subjects (36.4%). SVR rate significantly (P < 0.0001) decreased with 10-year age increments in both sexes. Multivariate logistic regression analysis revealed that age, F score, platelet count, and HCV load were SVR-related factors. In study 2, SVR rate in the 72-week group (67.1%) was significantly (P = 0.0020) higher than in the 48-week group (46.2%).
Conclusions: Patients with CHCV genotype 1 infection should be treated with PEG-IFN plus ribavirin combination therapy as early as possible, and 72 weeks' treatment is recommended in patients with LVR regardless of age.