Significance of early measurement of serum hepatitis C virus RNA in predicting response to interferon therapy in patients with chronic hepatitis C

Background: Interferon can induce complete clearance of hepatitis C virus (HCV) in some patients with chronic hepatitis C. However, various side effects often require cessation of administration during the treatment period. Early prediction of response to interferon would be helpful. We evaluated measurement of serum HCV RNA 2 weeks after starting interferon as a predictor of response. Methods: The presence of HCV RNA was measured in serum 2 weeks after starting therapy in 85 patients receiving natural interferon tx (total 480MU). Results: Twenty-seven of 38 patients (71.1%) in whom serum HCV RNA had disappeared at 2 weeks achieved a sustained response. Only two out of 47 patients (4.3%) in whom serum HCV RNA had not disappeared at 2 weeks achieved a sustained response. Of 42 patients with pre-treatment HCV RNA concentrations less than 1 x 10 6 eq/ml, 26 of 30 patients (86.7%) whose HCV RNA had disappeared at 2 weeks achieved a sustained response, while only one of 12 patients (8.3%) whose HCV RNA was still detectable at 2 weeks had a sustained response. Conclusion: Clearance of serum HCV RNA after 2 weeks of treatment with interferon was more likely in patients with lower pre-treatment HCV RNA concentrations and they had a high likelihood of achieving a sustained response. In patients in whom serum HCV RNA was still detectable after 2 weeks of interferon therapy, a sustained response was most unlikely.