Indices of initial hepatitis C virus RNA reduction rate to predict efficacy of interferon-beta followed by peginterferon plus ribavirin for genotype 1b high viral load.

Aim: Initial hepatitis C virus (HCV) RNA reduction was investigated as a potential index for sustained virological response (SVR) in the treatment of interferon (IFN)-β followed by peginterferon plus ribavirin (PEG IFN/RBV).

Methods: The treatment course was retrospectively analyzed in 64 genotype 1b patients with a HCV RNA level of 5.0 logIU/mL or higher. IFN-β was administrated twice a day for 2 weeks followed by 24 or 48 weeks of PEG IFN/RBV. The serum HCV RNA level was measured by real-time polymerase chain reaction before administration and at 1, 2 and 4 weeks of therapy.

Results: By the duration of PEG IFN administration, the SVR rates were 11% (2/18, <19 weeks), 64% (23/36, 20-24 weeks) and 40% (4/10, 25-72 weeks) (P = 0.0011, χ(2) -test). The SVR rate was high in patients in whom the HCV RNA level had decreased by 2.5 logIU/mL or greater at 1 week of IFN-β (29/55 [53%] vs 0/9 [0%], P = 0.0029, χ(2) -test). Among these patients, the SVR rate was even higher in those with continuous reduction in the first 2 weeks after the switch to PEG IFN/RBV (27/45 [60%] vs 2/10 [20%], P = 0.0048). Age below 65 years, no previous IFN course and good initial HCV RNA reduction were significantly associated with SVR on multivariate analysis, and the SVR rate was 95% (18/19) among these patients.

Conclusion: The 2.5 logIU/mL reduction in HCV RNA at 1 week of IFN-β and the continuous reduction just after the switch to PEG IFN/RBV are important SVR-predictive indices.