Efficacy of IFN therapy based on duration period of negative HCV-RNA during IFN administration

We assessed the relationship between the duration period of negative hepatitis C virus (HCV)-RNA during interferon (IFN) therapy and the efficacy after prolonged IFN therapy in patients with HCV-genotype 1b and high virus load of more than 1 mega equivalents/ml (Meq/ml) retrospectively. A total of 100 patients who had HCV-genotype 1b and a high virus load of more than 1 Meq/ml and were treated with natural IFN-alpha for more than 12 months were enrolled in this trial. These patients were given 6 MU of IFN daily for 8 weeks, followed by three times weekly for another more than 44 weeks. The HCV-RNA pattern during IFN therapy according to negative or positive of the serum HCV-RNA by reverse transcription nested polymerase chain reaction (RT-nested PCR) from 2 months after the initiation of IFN to the termination of IFN were classified as follows: group 1: constant negative HCV-RNA (n=41 cases), group 2: constant positive HCV-RNA (n=35 cases), group 3: HCV-RNA pattern except for group 1 or group 2 (n=24 cases). A complete response (CR) was defined as negative HCV-RNA by RT-nested PCR at two points, 3 and 6 months after the completion of IFN therapy. CR rate was 58.5% (24 cases) in group 1, but CR rate in group 2 or group 3 was 0%. In group 1, the CR rate was 100% (10/10) in patients with negative HCV-RNA constantly for period of more than 24 months during IFN therapy. On the other hand, all patients who had positive HCV-RNA 2 months after the initiation of IFN did not get CR. In conclusion, it seems to us that the attainment of constantly negative HCV-RNA for the period of more than 24 months during IFN therapy is highly related to CR.