Background and aim
Three gene polymorphisms, interferon-lambda-3 (IL28B), inosinetriphosphatase (ITPA) and bilirubinuridine diphosphate-glucuronosyltransferase (UGT1A1) are associated with treatment (interferon and ribavirin) efficacy and adherence in patients with chronic hepatitis C. The hypothesis was that fibrosis stage estimated with FibroTest instead of biopsy was still an independent predictive factor of sustained virologic response (SVR) when these new polymorphisms were assessed.
Patients receiving standard of care treatment were retrospectively analyzed with determination of IL28B, ITPA, and UGT1A1 polymorphisms. Baseline prognostic factors were combined using logistic regression analysis in a training group (157 patients) and validated in avalidation group (79 patients).
The combination of the five most predictive factors (HCV genotype 2/3, IL28B genotype, FibroTest, ActiTest and viral load) in the training population had AUROC for SVR=0.743 (0.655–0.810; P<0.0001 vs. random), which was validated in the validation population, AUROC=0.753 (0.616–849; P=0.0007 vs. random, not different from training P=0.88). FibroTest remained significant [OR=4.20 (2.59–12.50); P=0.03] after assessment of the IL28B CC, HCV genotype and viral load.
Fibrosis stage assessed by FibroTest is an independent predictor of SVR, after accounting for the IL28B genetic polymorphism. A combination of five baseline biomarkers could simplify the baseline prediction of SVR.