Effect of Ribavirin on Viral Kinetics and Liver Gene Expression in Chronic Hepatitis C

Background/Aims: Ribavirin improves treatment response to pegylated-interferon (PEG-IFN) in chronic hepatitis C but the mechanism remains controversial. We studied correlates of response and mechanism of action of ribavirin in treatment of hepatitis C. Methods: 70 treatment-nave patients were randomized to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFN alfa-2a and ribavirin at standard doses and durations. Patients were randomized to undergo a liver biopsy either 24 hours before, or 6 hours after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by the nCounter platform. Temporal changes in ISG expression were assessed by qPCR in peripheral-blood mononuclear cells (PBMC) and by serum levels of IP-10. Results: After four weeks of ribavirin monotherapy, HCV levels decreased by 0.50.5 log10 (p=0.009 vs. controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting the induction of ISGs by PEG-IFN, did not modify the virological response to subsequent PEG-IFN and ribavirin treatment. However, biochemical, but not virological response to ribavirin monotherapy predicted response to subsequent combination treatment (rapid virological response, 71% in biochemical responders vs. 22% non-responders, p=0.01; early virological response, 100% vs. 68%, p=0.03, sustained virological response 83% vs. 41%, p=0.053). Ribavirin monotherapy lowered serum IP-10 levels but had no effect on ISG expression in PBMC. Conclusion: Ribavirin is a weak antiviral but its clinical effect in combination with PEG-IFN seems to be mediated by a separate, indirect mechanism, which may act to reset the interferon responsiveness in HCV-infected liver. Ribavirin pretreatment does not alter the clinical outcome of subsequent combination therapy.

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Rotman Y, Noureddin M, Feld JJ, Guedj J, Witthaus M, Han H, Park YJ, Park SH, Heller T, Ghany MG, Doo E, Koh C, Abdalla A, Gara N, Sarkar S, Thomas E, Ahlenstiel G, Edlich B, Titerence R, Hogdal L, Rehermann B, Dahari H, Perelson AS, Hoofnagle JH, Liang TJ