Effect of ribavirin on viral kinetics and liver gene expression in chronic hepatitis C

Abstract

Objective: 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.

Design: 70 treatment-naive patients were randomised to 4 weeks of ribavirin (1000-1200 mg/d) or none, followed by PEG-IFNα-2a and ribavirin at standard doses and durations. Patients were also randomised to a liver biopsy 24 h before or 6 h after starting PEG-IFN. Hepatic gene expression was assessed by microarray and interferon-stimulated gene (ISG) expression quantified by 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 4 weeks of ribavirin monotherapy, hepatitis C virus (HCV) levels decreased by 0.5±0.5 log10 (p=0.009 vs controls) and ALT by 33% (p<0.001). Ribavirin pretreatment, while modestly augmenting ISG induction 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.

Conclusions: Ribavirin is a weak antiviral but its clinical effect seems to be mediated by a separate, indirect mechanism, which may act to reset IFN-responsiveness in HCV-infected liver.

Trial registration: ClinicalTrials.gov NCT00718172.

Keywords: Hepatitis C; Interferon-Alpha.

Figures

Figure 1

Study design. Arrows note timing of liver biopsy. *Ribavirin dose 1000 mg/d for patients weighing less than 75 kg, 1200 mg/d for heavier patients, irrespective of viral genotype. †Ribavirin dose 800 mg/d for patients with genotype 2/3, weight-based 1000–1200 mg/d for all other genotypes. ‡Treatment duration 24 weeks for genotypes 2/3, 48 weeks for all others.

Figure 2

Effect of ribavirin monotherapy for 4 weeks on serum levels of HCV-RNA (A) and ALT activity (B). Solid line – ribavirin treatment. Dotted line – untreated controls. Mean ± Standard Error (SE).

Figure 2

Effect of ribavirin monotherapy for 4 weeks on serum levels of HCV-RNA (A) and ALT activity (B). Solid line – ribavirin treatment. Dotted line – untreated controls. Mean ± Standard Error (SE).

Figure 3

Virological response to PEG-IFN and RBV of patients pre-treated with 4 weeks of RBV monotherapy and controls during the first 7 days (A) and weeks 1 to 4 (B) of combination treatment. Virological response to Peg-IFN and RBV combination therapy stratified by virological (C) and biochemical (D) response to previous RBV monotherapy. Means ± SE.

Figure 3

Virological response to PEG-IFN and RBV of patients pre-treated with 4 weeks of RBV monotherapy and controls during the first 7 days (A) and weeks 1 to 4 (B) of combination treatment. Virological response to Peg-IFN and RBV combination therapy stratified by virological (C) and biochemical (D) response to previous RBV monotherapy. Means ± SE.

Figure 3

Virological response to PEG-IFN and RBV of patients pre-treated with 4 weeks of RBV monotherapy and controls during the first 7 days (A) and weeks 1 to 4 (B) of combination treatment. Virological response to Peg-IFN and RBV combination therapy stratified by virological (C) and biochemical (D) response to previous RBV monotherapy. Means ± SE.

Figure 3

Virological response to PEG-IFN and RBV of patients pre-treated with 4 weeks of RBV monotherapy and controls during the first 7 days (A) and weeks 1 to 4 (B) of combination treatment. Virological response to Peg-IFN and RBV combination therapy stratified by virological (C) and biochemical (D) response to previous RBV monotherapy. Means ± SE.

Figure 4

Average hepatic expression level of 135 ISGs according to treatment at the time of liver biopsy, expressed in arbitrary units (A, mean ± SE) or as fold induction relative to the average expression in controls (B, geometric mean ± 95% confidence intervals, CI). Significance tested using Wilcoxon’s signed-ranks test.

Figure 4

Average hepatic expression level of 135 ISGs according to treatment at the time of liver biopsy, expressed in arbitrary units (A, mean ± SE) or as fold induction relative to the average expression in controls (B, geometric mean ± 95% confidence intervals, CI). Significance tested using Wilcoxon’s signed-ranks test.

Figure 5

Hierarchical clustering of patients according to the hepatic expression of 135 ISGs (nCounter assay). The color labels at the bottom mark whether tissue was obtained before the initial PEG-IFN injection (red: groups A & C), or 6 hours after the first injection (blue: groups B & D). Subsequent responses after 12 weeks of combination treatment are labeled beneath color code as cEVR (complete EVR, non-detectable virus at week 12, pEVR (partial EVR, > 2 log10 decline but still detectable HCV-RNA) or Null responder (< 2 log10 decline).

Figure 6

Serial measurements of serum IP10 levels during treatment (A). Solid line – patients treated with RBV monotherapy on weeks −4 to 0. Dotted line – controls with no pre-treatment. (B) Fold change in serum IP10 levels after 4 weeks of RBV or control and 6 hours after injecting interferon.

Figure 6

Serial measurements of serum IP10 levels during treatment (A). Solid line – patients treated with RBV monotherapy on weeks −4 to 0. Dotted line – controls with no pre-treatment. (B) Fold change in serum IP10 levels after 4 weeks of RBV or control and 6 hours after injecting interferon.