1. Volume 139, Issue 1, Pages 154-162.e4 (July 2010)
Ribavirin Improves Early Responses to Peginterferon Through Improved Interferon Signaling 
Jordan J. Feld, Glen A. Lutchman, Theo Heller, Koji Hara, Julie K. Pfeiffer, Richard D. Leff, Claudia Meek, Maria Rivera, Myung Ko, Christopher Koh, Yaron Rotman, Marc G. Ghany, Vanessa Haynes–Williams, Avidan U. Neumann, T. Jake Liang, Jay H. Hoofnagle 
Gastroenterology 
Volume 139, Issue 1, Pages e4 (July 2010)
DOI: /j.gastro
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2. Figure 1
Mean serum log10IU/mL of hepatitis C virus RNA from (A) day 0 to day 3, (B) day 7 to day 28, and (C) day 28 to day 84 comparing patients receiving peginterferon alone (Peg) to those receiving both peginterferon and ribavirin (Peg+Rbv) during treatment.
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3. Figure 2
Comparison of individual values for early viral kinetics by treatment group. (A) There was no difference between the 2 groups in first-phase decline defined as the absolute reduction in hepatitis C virus (HCV) RNA concentration from 0 to 48 hours. (B) Patients receiving both peginterferon and ribavirin had a more rapid second-phase slope (regression line of HCV RNA from days 7 to 28) than those on peginterferon alone. However, (C) the difference between the 2 groups was seen largely in individuals with an adequate first-phase decline (≥0.5 log10IU/mL). P, peginterferon alone; P + R, peginterferon and ribavirin.
Gastroenterology  , e4DOI: ( /j.gastro )
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4. Figure 3
Correlation between first- and second-phase viral kinetic decline. Almost all patients (12 of 13) on combination therapy (open triangles) who had an adequate first-phase response had an adequate second-phase slope. In contrast, only 9 of 16 (56%) patients on peginterferon alone (closed circles) (P = .04) with an adequate first-phase response had an adequate second-phase response. The horizontal dotted line indicates an adequate first-phase decline (0.5 log10IU/mL) and the vertical dotted line indicates an adequate second-phase slope (0.35 log10IU/week).
Gastroenterology  , e4DOI: ( /j.gastro )
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5. Figure 4
Fold-induction of serum interferon-γ inducible protein 10 (IP10) levels at 12 hours after the initial injection of peginterferon in the 2 treatment groups. (A) Patients receiving the combination of peginterferon and ribavirin had greater induction of IP10 at 12 hours than those on peginterferon alone. (B) Similar to viral kinetics, the increase in IP10 fold-induction at 12 hours, 3, and 7 days with combination therapy was seen largely in patients with an initial adequate response to peginterferon (first-phase decline ≥0.5 log10IU/mL). (C) IP10 induction at 12 hours correlated with second-phase slope, but (D) only in those with an adequate first-phase decline, suggesting that interferon-stimulated genes (ISG) induction is driving viral decline. Only indicated comparisons between P and P+R with an adequate first-phase decline at each time point were statistically significant using the Mann-Whitney U test. (***P = .001; **P = .01; *P = .03). P, peginterferon; P+R, peginterferon + ribavirin.
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6. Figure 5
Mutation frequency with and without ribavirin. There was no difference in (A) synonymous or (B) nonsynonymous mutations between groups. The (C) error rate and was also similar between groups at all time points measured.
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7. Supplementary Figure 1
Correlation between interferon-γ inducible protein 10 (IP10) fold-induction at 12 hours and first-phase viral decline.
Gastroenterology  , e4DOI: ( /j.gastro )
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8. Supplementary Figure 2
Fold induction of serum (A) monokine induced by interferon-γ (MIG) and (B) monocyte chemoattractant protein 1 (MCP1) at 12 hours after the initial dose of peginterferon in the 2 treatment groups. Similar to interferon-γ inducible protein 10 (IP10), induction of both MIG and MCP1 was greater in patients receiving the combination of peginterferon and ribavirin than peginterferon alone. The difference in cytokine induction was most pronounced at 12 hours and was significant only in patients with an adequate first-phase decline. Differences remained significant at day 3 for (C) MIG and (D) MCP-1 but levels were near baseline by day 7. Only indicated comparisons between peginterferon alone (P) and peginterferon and ribavirin (P + R) with an adequate first phase decline at each time point were statistically significant using the Mann Whitney U test (*P < .05; **P < .01). MIG, monokine induced by interferon-γ; MCP1, monocyte chemoattractant protein 1.
Gastroenterology  , e4DOI: ( /j.gastro )
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9. Supplementary Figure 3
Correlation between ribavirin concentration and early viral kinetics and between interferon-γ inducible protein 10 (IP10) induction. Ribavirin concentration at day 3 did not correlate with (A) first- or (B) second-phase viral decline. (C) There was a nonsignificant trend between ribavirin concentration at day 28 and second-phase decline. (D) Ribavirin concentration at day 3 correlated with IP10 fold-induction at 12 hours, but only in those with an adequate first-phase decline (≥0.5 log10IU/mL).
Gastroenterology  , e4DOI: ( /j.gastro )
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10. Supplementary Figure 4
Kaplan-Meier analysis comparing the time until hepatitis C virus (HCV) RNA was first undetectable by polymerase chain reaction (<50 IU/mL). There was no difference between groups as assessed by the log-rank test.
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11. Supplementary Figure 5
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