Background and aims: In chronic hepatitis C patients with genotype 1b and a high viral load, the sustained virological response (SVR) rate remained as low as 2-3% with conventional interferon (IFN) monotherapy, but improved to more than 20% with IFN alpha-2b plus ribavirin combination therapy. This study examined the therapeutic effects and predictors of this combination therapy.
Methods: Subjects were 105 patients with chronic hepatitis C (73 males, 32 females) with a median age of 53 years (range 19-70 years). Seventy-two patients had genotype lb and 33 patients had genotype 2 (2a or 2b). Six million units (MU) or 10 MU of IFN alpha-2b was administered by intramuscular injection six times a week for the first 2 weeks, and the same amount of IFN was administered three times a week for the following 22 weeks. During the IFN administration period, 600-800 mg of oral ribavirin was administered daily. Patients who were hepatitis C virus (HCV)-RNA negative 24 weeks after the completion of administration were defined as SVR.
Results: The overall SVR rate was 39%; 22.2% for the genotype 1b group and 75.8% for the genotype 2 group, and the difference between the groups was significant (P < 0.0001). Multivariate logistic regression analysis indicated that the factors that contributed to SVR include genotype 2, age (younger than 53 years), and an increase in Th2 measured by flow cytometry before and 4 weeks after start of treatment.
Conclusions: The overall SVR rate of IFN alpha-2b plus ribavirin combination therapy for 24 weeks was 39%, and contributing factors for SVR rate include genotype 2, age younger than 53 years and elevated Th2.