Prediction of response to peginterferon-alfa-2b plus ribavirin therapy in Japanese patients infected with hepatitis C virus genotype 1b.

Variation at the IL-28B locus was recently reported to be a significant predictive factor of viral response to pegylated-interferon plus ribavirin combination therapy against chronic hepatitis C. Predictive factors for the effect of therapy, including IL-28B polymorphism rs8099917 and viral and clinical factors were investigated. A total of 288 patients were enrolled who were chronically infected with hepatitis C virus (HCV) genotype 1b and treated with combination therapy. Among them, 87 patients completed 48 weeks of therapy without dose reduction or discontinuation. In multivariate regression analysis, the rs8099917 TT genotype was the only independent factor significantly associated with sustained viral response (P = 0.016, OR 61.5), whereas substitutions at amino acid 70 (aa 70) of the HCV core protein (P = 0.038, OR 5.9) and non-TT genotypes (P = 0.002, OR 17.2) were associated with nonvirological response. Both factors were also associated with viral dynamics during the initial stage of the therapy. Correlation analysis revealed that rs8099917 genotype was correlated with γ-glutamyl transpeptidase, hyaluronic acid, and HCV core aa 70. In conclusion, host (IL-28B polymorphism) and viral (aa 70) factors independently affect response to combination therapy.
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