SERUM HCV RNA TITER AT THE END OF INTERFERON THERAPY PREDICTS THE LONG-TERM OUTCOME OF TREATMENT

Background/Aims: Serum HCV RNA was quantitated by the competitive poly merase chain reaction before, at the end of, and after interferon ther apy, We assessed whether serum HCV RNA titer at the end of interferon therapy predicts the long-term outcome of treatment. Methods/Results: Of 71 patients treated with various doses of interferons, 21 became ne gative for HCV RNA persistently during follow up of 2 years, and they were considered as complete responders, The serial determinations of H CV RNA titer for each individual showed that in patients with HCV RNA negative at the end of therapy, the complete response rate was quite h igh (78.6%), while in patients with HCV RNA titer greater than or equa l to 10(4) copies/ml at the end of therapy, none became complete respo nders in long-term follow up, The percentage decreasing to greater tha n or equal to 10(2) copies/ml of HCV RNA at termination of interferon tended to be higher in patients with genotype 2a (14/21, 66.7%) than i n those with genotype Ib (18/42, 42.9%). The complete response rate of patients whose viral load was less than or equal to 10(2) copies/ml a t termination of interferon was significantly higher in genotype 2a (1 1/14, 78.6%) than in genotype Ib (5/18, 27.8%) (p < 0.01), Pretreatmen t HCV RNA titer appeared to correlate to the titer at the end of thera py (r=0.596, p < 0.001); even when HCV RNA decreased to less than or e qual to 10(2) copies/ml, the higher pretreatment titer indicated a low er likelihood of complete response (p < 0.05). Conclusions: These resu lts indicate that HCV genotype and pretreatment viral titer are import ant factors in the response to interferon therapy, In addition, our st udy suggests that it is possible to stop interferon therapy at an appr opriate time by monitoring HCV RNA titer.