Background/aims: Interferon treatment is more effective in patients with chronic hepatitis C infected with genotype 2a virus than those with genotype 1b virus. We analyzed patients with chronic hepatitis C treated by interferon in our clinics to develop a more effective regimen of interferon treatment for patients with genotype 2 virus infection.
Methodology: We retrospectively analyzed the virological response of 36 patients with chronic hepatitis C with a high viral load, including 28 cases infected with the genotype 2a virus and 8 cases with the genotype 2b virus. The serum viral load of these patients were 6.0 log copies/mL and higher by the competitive polymerase chain reaction assay method. All patients could be treated with interferon-alpha or -beta for 6 months. Eleven patients were administered 6 million units of interferon-beta once daily for 6 weeks and then thrice weekly (group A). Twelve patients were administered 6 million units of interferon-alpha daily initially for 2 weeks and then thrice weekly (group B), and 10 patients were treated with the same dose of interferon-alpha thrice weekly from the first administration (group C). We decided the criteria of complete remission as the absence of serum HCV-RNA at both points of the end of interferon treatment and 6 months later.
Results: For all patients with genotype 2a virus infection, the complete remission, transient response and no response rates were 46.4%, 39.3% and 14.3%, respectively. The complete remission rates in group A, B and C were 100%, 41.7% and 20%, respectively. The transient remission rates in group B and C were 41.7% and 60%, respectively. The no response rates in group B and C were 16.7% and 20%, respectively. All patients with a high viral load of genotype 2a virus showed eradicated serum HCV-RNA virus in group A. The eradication rate of serum HCV-RNA in patients infected with the genotype 2a virus in group A was significantly higher than that of group B (p < 0.02) or group C (p < 0.01). For all patients with genotype 2b virus infection, complete remission, transient remission and no response rates were 12.5%, 50.0% and 37.5%, respectively. The complete remission rate of patients with the genotype 2b virus in group A and group B plus C was 0% and 25.0%, respectively. The eradication rate of patients with the genotype 2a virus in group A was significantly higher than that of patients with the genotype 2b virus (p < 0.01).
Conclusions: These findings suggest that the initial sufficient dose of interferon administration is effective to eradicate serum HCV-RNA in patients with a high viral load of genotype 2a virus in chronic hepatitis C.