Large dose natural interferon alpha therapy for patients with chronic hepatitis C.

To evaluate the efficacy of large dose interferon treatment for patients with chronic hepatitis C virus (HCV) infection, we studied 99 Japanese patients treated with either 6 million units (MU) or 9 MU natural interferon alpha. Serum samples were tested for HCV RNA by polymerase chain reaction (PCR). HCV RNA genotypes were determined by PCR with type-specific preimers, and the HCV RNA level was measured by competitive PCR. HCV RNA was detected in all patients, prior to the initiation of treatment. We examined interleukin-1 receptor antagonist (IL-1 Ra) by enzyme-linked immunosorbent assay. Forty-four patients were treated with 9 MU natural interferon alpha for 24 weeks (group A), and fifty-five patients were treated with 6 MU natural interferon alpha for 24 weeks (group B). There were no significant differences in HCV RNA levels, HCV RNA genotype or histological activity index (HAI) score between the two groups. Of the 94 patients who completed this treatment, nine (23.1%) in group A and 14 (25.5%) in group B sustained elimination of HCV RNA throughout a 6-month follow-up. There were no differences in the rate of complete response when comparing HCV RNA genotype, levels and HAI score and no significant differences in elevation of IL-1 Ra levels between the two groups. Five of group A patients refused further treatment because of severe side effects such as retinal hemorrhage, while no patient in group B had severe side effects. Thus, large dose natural interferon alpha treatment confers no additional benefit to the patient, compared with the current use of a lower dose.