Antiviral Treatment Of Hcv Carriers With Normal Alt

Background: Ribavirin use and higher ribavirin doses are associated with accelerated viral decay during the very early phase of ant-HCV therapy.An interference of abacavir with ribavirin intracellular phosphorilation has been hypothesized.Thus, concurrent abacavir use should impair the early phases of viral decay during anti HCV treatment.A negative interaction seem to be confirmed by preliminary data from retrospective studies showing a negative impact of abacavir use on the sustained response to pegylated interferon and ribavirin combination treatment in HIV infected patients with chronic hepatitis C. However this association could be biased by confounders and not due to a reduced potency of anti HCV treatment.Aims and Methods: We analyzed the impact of concurrent abacavir use on the rate of Rapid Virologic Response (HCV-RNA <50 IU/mL after 4 weeks) in 337 patients from a large observational multicenter cohort study treated with ribavirin >10.6 mg/kg/d in combination with Pegylated Interferon alfa 2b 1.5 mcg/Kg or Pegylated Interferon alfa 2a 180 mcg per week and with an available measurement of HCV-RNA after 4 weeks of treatment.Mann Whitney or t-test and Fisher's exact test were used for bivariate analysis when indicated.Logistic regression was used for multivariate analysis.Results: RVR was observed in 25%.Abacavir was prescribed in 55 subjects (16%): 14% of them showed RVR [OR 0.46 (95 CI 0.21-1.02)p = 0.06].In multivariate analysis abacavir use was associated with RVR [Adjusted OR 0.43 (95 CI 0.18-0.99)p = 0.049] after adjusting for HCV genotype, age, HCV-RNA levels, zidovudine use and ribavirin dose per Kg of body weight.Abacavir use was not associated with a lower decline of haemoglobin after 4 weeks (mean±SD was 2.1±1.5 g/L in those treated with abacavir vs. 2.0±1.3 g/L in those not exposed to abacavir).Conclusions: Abacavir use was associated with an impaired antiviral effect of Pegylated Interferon and ribavirin in HIV infected patients.If this interaction is due to competition for intracellular phosphorilation this should not occur in erythrocytes.In fact haemolytic anaemia that is caused by accumulation of ribavirin triphosphate in red blood cells is not reduced by concurrent abacavir treatment.