Prediction of a Null Response to Pegylated Interferon α-2b Plus Ribavirin in Patients with High Viral Load Genotype 1b Hepatitis C

BACKGROUND/AIMS The present study aimed to clarify whether virological response within 2 weeks after therapy initiation can predict a null response to pegylated interferon α-2b plus ribavirin therapy in patients with high viral load genotype 1b hepatitis C. METHODS The participants consisted of 72 patients with high viral load genotype 1b. The dynamics of viral load within 2 weeks were measured. RESULTS Significant differences between null responders and nonnull responders were noted for interleukin (IL)-28B genotype, amino acid 70 substitution, α-fetoprotein, low-density lipoprotein cholesterol, hyaluronic acid, and viral response. The area under the curve (AUC) for the receiver operating characteristic curve of the hepatitis C virus (HCV) RNA level decline at 2 weeks (AUC=0.993) was the highest among the factors predicting the null response. When the cutoff value for the HCV RNA level decline at 2 weeks was set at 0.80 log, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting a null response were 82%, 96%, 82%, 96%, and 94%, respectively. In comparison, values for the non-TT and mutant type of amino acid 70 substitution were similar to those for HCV RNA level decline at 2 weeks. CONCLUSIONS Virological response at 2 weeks or the combination of IL-28B and amino acid 70 substitution are accurate predictors of a null response.