Association of ITPA polymorphism with outcomes of peginterferon-α plus ribavirin combination therapy

AIM:To analyzed the association between inosine triphosphatase(ITPA)(rs1127354) genotypes and sustained virological response(SVR) rates in peginterferon(Peg-IFN)α + ribavirin(RBV) treatment.METHODS:Patients who underwent Peg-IFNα + RBV combination therapy were enrolled(n = 120) and they had no history of other IFN-based treatments.Variation in hemoglobin levels during therapy,cumulative reduction of RBV dose,frequency of treatment withdrawal,and SVR rates were investigated in each ITPA genotype.RESULTS:In patients with ITPA CC genotype,hemoglobin decline was significantly greater and the percentage of patients in whom total RBV dose was < 60% of standard and/or treatment was withdrawn was significantly higher compared with CA/AA genotype.However,SVR rates were equivalent between CC and CA/AA genotypes,and within a subset of patients with Interleukin 28B(IL28B)(rs8099917) TT genotype,SVR rates tended to be higher in patients with ITPA CC genotype,although the difference was not significant.CONCLUSION:ITPA CC genotype was a disadvantageous factor for Peg-IFNα + RBV treatment in relation to completion rates and RBV dose.However,CC genotype was not inferior to CA/AA genotype for SVR rates.When full-length treatment is accomplished,it is plausible that more SVR is achieved in patients with ITPA CC variant,especially in a background of IL28B TT genotype.