Utility of hepatitis C virus RNA levels for predicting the therapeutic efficacy of interferon.

We studied the levels of serum hepatitis C virus (HCV)-RNA, the HCV genotype before interferon therapy, and the kinetics of serum HCV-RNA at the initial stages of therapy to determine their utility in predicting the therapeutic efficacy of interferon in 44 patients with chronic hepatitis C infection. We also looked at the efficacy of repeated interferon treatment in relation to the kinetics of serum HCV-RNA. The level of serum HCV-RNA determined by a branched DNA probe assay before interferon treatment and that by a reverse transcription nested polymerase chain reaction assay during the initial stages of interferon administration were useful for predicting the efficacy of treatment. Furthermore, detection of serum HCV-RNA by the reverse transcription nested polymerase chain reaction assay after the completion of interferon therapy indicated relapse at its earliest stage. In patients who experience relapse, repeated treatment with an appropriate dose of interferon before an increase in viral levels may increase the proportion of complete responses.