Accurate prediction of response to interferon therapy by repeated measurement of hepatitis C virus core protein in patients with chronic hepatitis C

Objective and Methods: Serum levels of hepatitis C virus (HCV), a predictor of the response to interferon (IFN) therapy, can fluctuate widely in patients with chronic hepatitis C, even without antiviral therapy. In order to increase the accuracy of predicting the response to therapy, serum samples from 134 patients with chronic hepatitis C were collected twice: 1.0-4.5 months before and just before the start of IFN therapy, and were tested for HCV core protein by a fluorescent enzyme immunoassay. Results: Forty-one (31%) patients had a complete response to IFN and 93 (69%) had no response. The most useful cutoff value between high and low viral loads for predicting the response to therapy was 40 pg/ml of HCV core protein. A complete response was obtained more frequently in 32 of 45 patients with persistently low viral loads than in those with persistently high viral loads (7 of 71) (p < 0.0001). In 2 of 18 patients with a low viral load at one time point but a high viral load at another, the rate of complete response was similar to that in patients with persistently high viral loads. Conclusion: Prediction of the response to IFN therapy based on HCV core protein measurement at two time points before therapy is more reliable than that based on HCV core protein measurement at only one time point. Copyright (C) 2002 S. Karger AG, Basel.