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 alpha-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, a-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.