IFNL4-ΔG genotype is associated with slower viral clearance in hepatitis C, genotype-1 patients treated with sofosbuvir and ribavirin

Response to pegylated interferon-alpha and ribavirin (IFN-α/RBV) treatment for chronic hepatitis C virus (HCV) infection is influenced by host genetic factors, but their role for IFN-α-free, direct-acting antiviral (DAA) regimens is unclear. An exonic deletion allele (IFNL4-ΔG) bolsters the established association with IFN-α/RBV therapy treatment outcome of another IFNL4 variant, rs12979860, which is located upstream of IFNL3 (IL28B). We report that in patients treated with the DAA sofosbuvir along with RBV, IFNL4-ΔG is associated with slower early viral decay, due to slower loss of free virus (P = .039) and decreased drug efficacy (P = .048), suggesting functional relevance of IFN-λ4 in IFN-α-free DAA therapies.

Impact of age on viral kinetics of peginterferon alfa-2a/ribavirin in chronic hepatitis C: final analysis from the PROPHESYS cohort

The population of patients with chronic hepatitis C viral infection is ageing; however, elderly, hepatitis C-infected patients are understudied and less frequently treated. This subanalysis of data from the multinational PROPHESYS study examined associations between age (≤65 vs >65 years), on-treatment virological response and sustained virological response (SVR) in patients treated with peginterferon alfa-2a (40KD)/ribavirin in accordance with local licences. PROPHESYS comprised three cohorts studied in 19 countries according to country-specific legal and regulatory requirements. This subanalysis includes treatment-naive HCV mono-infected patients assigned to receive peginterferon alfa-2a (40KD)/ribavirin, with 6276 individuals aged ≤65 years and 349 aged >65 years. Rapid virological response (RVR) rates by Week 4 were consistently lower in older genotype (G) 1 (21.6% vs 27.2% in younger patients), G2 (80.7% vs 85.1%) and G3 (60.0% vs 74.2%) patients. SVR rates were significantly lower (29.8% vs 43.0%) and relapse rates significantly higher (43.1% vs 26.7%) in older G1 patients (P = 0.0002 vs ≤65 years). In contrast, SVR and relapse rates were similar in G2 and G3 patients regardless of age. The positive predictive value of RVR for SVR was comparable in older and younger G1 patients (66.7% vs 68.6%, respectively) and higher in older G2 (80.7% vs 75.6%) and G3 (77.8% vs 66.8%) patients. Virological response rates are generally lower in elderly CHC patients, and RVR is a reliable positive predictor of SVR in patients >65 years.

Single-dose infliximab in hepatitis C genotype 1 treatment-naive patients with high serum tumour necrosis factor-alpha does not influence the efficacy of pegylated interferon alpha-2b/ribavirin therapy

BACKGROUND

Serum tumour necrosis factor-alpha (TNF-α) levels correlate negatively with hepatitis C virus (HCV) antiviral response.

OBJECTIVES

To test the hypothesis that a single infliximab induction dose would positively influence on-treatment virological response and sustained virological response (SVR).

METHODS

The present study was a phase IIIB, randomized, prospective, open-label pilot trial conducted at eight Canadian sites. Treatment-naive HCV genotype 1-infected patients 18 to 65 years of age with high serum TNF-α values (>300 pg⁄mL) were randomly assigned to receive a single pretreatment induction infliximab infusion (5 mg⁄kg) seven days before antiviral therapy (arm A) or no pretreatment (arm B). All patients received pegylated interferon α2b (1.5 μg⁄kg⁄week) plus weight-based ribavirin (800 mg⁄day to 1400 mg⁄day) for up to 48 weeks.

RESULTS

Eighty-five patients (arm A [n=41], arm B [n=44]; 70% male) received pegylated interferon α2b. The mean age (48.1 years), race (81% white) and METAVIR fibrosis stage (F0-2 = 79%, F3-4 = 21%) were similar between groups. Infliximab was well tolerated without attributable severe adverse events; 56.5% completed the study (arm A [n=21], arm B [n=27]). Most discontinuations were due to virological failure at weeks 12 (n=20 [23.5%]) and 24 (n=7 [8.2%]) and did not differ according to group. Numerically lower proportions of infliximab recipients achieved rapid virological response (19.5% versus 36.4%), complete early virological response (43.9% versus 59.1%) and SVR (34.1% versus 52.3%). However, between-group differences did not reach statistical significance. No differences in adverse event profile or laboratory measures were noted.

CONCLUSION

A single infliximab dose before pegylated-interferon α2b and ribavirin therapy did not result in greater viral decline during the first 12 weeks of HCV therapy or improved SVR.

Impact of ribavirin priming on viral kinetics and treatment response in chronic hepatitis C genotype 1 infection

Ribavirin amplifies the interferon-alpha (IFN) signalling cascade. As ribavirin needs 4 weeks to reach steady state, ribavirin priming may optimize hepatic IFN sensitivity before starting a pegylated (PEG)-IFN/ribavirin combination therapy. This study investigated potential benefits of ribavirin priming prior to PEG-IFN2a/ribavirin combination therapy on viral kinetics, on-treatment and sustained virological response (SVR) in chronic hepatitis C virus (HCV) genotype 1 infection. Sixty-eight treatment naive patients were randomized 2:2:1 to ribavirin (ribavirin arm) or placebo (placebo arm) or PEG-IFN2a (PEG-IFN2a arm) for 6 weeks prior to 12 weeks of PEG-IFN2a/ribavirin combination therapy within a double-blind, placebo-controlled trial. Then, standard PEG-IFN2a/ribavirin combination therapy according to the German guidelines was continued under the responsibility of the investigators. Ribavirin was given according to body weight and PEG-IFN2a at a dose of 180 μg subcutaneously once/week. During ribavirin priming, HCV RNA showed a decline of -0.58 log10  IU/mL (P < 0.001) that was unrelated to the IL28B rs12979860 genotype (CC vs CT/TT, P = 0.244). Ribavirin priming did neither increase the PEG-IFN2a-induced first- or second-phase viral decline (P values >0.100) nor on-treatment response or SVR (HCV RNA undetectable at week 12 of combination therapy: ribavirin arm 56%, placebo arm 38%, PEG-IFN2a arm 50%; SVR: ribavirin arm 41%, placebo arm 54%, PEG-IFN2a arm 50%; P values >0.300). In conclusion, ribavirin monotherapy showed a significant antiviral activity that was not influenced by the IL28B genotype. Ribavirin priming prior to PEG-IFN2a/ribavirin combination therapy did neither increase the first- or second-phase viral decline nor on-treatment response or SVR.

Telaprevir activity in treatment-naive patients infected hepatitis C virus genotype 4: a randomized trial

BACKGROUND

This partially blinded, randomized, phase 2a C210 study evaluated the antiviral activity of telaprevir-based regimens in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 4 infection.

METHODS

Twenty-four patients received telaprevir 750 mg every 8 hours for 15 days (T; n = 8), telaprevir in combination with pegylated interferon alfa-2a and ribavirin (Peg-IFN/RBV) for 15 days (TPR; n = 8), or Peg-IFN/RBV plus placebo for 15 days (PR; n = 8), followed by Peg-IFN/RBV for 46 or 48 weeks. The primary objective was to assess the effect of telaprevir on HCV RNA levels.

RESULTS

HCV RNA levels decreased slightly with T and PR; TPR produced substantial, rapid declines. On day 15, median reductions in the HCV RNA load from baseline were -0.77, -4.32, and -1.58 log10 IU/mL for T, TPR, and PR, respectively, and 0 patients in the T group, 1 in the TPR group, and 0 in the PR group had undetectable HCV RNA. Five of 8 patients who received telaprevir monotherapy had viral breakthrough within 15 days of treatment. Adverse event incidence was similar across treatments and comparable with the incidences from previous clinical trials. One patient (in T group) had a serious adverse event (considered unrelated to telaprevir) that led to treatment discontinuation.

CONCLUSIONS

Telaprevir with Peg-IFN/RBV had greater activity than Peg-IFN/RBV treatment or telaprevir monotherapy against HCV genotype 4. Telaprevir was generally safe and well tolerated. Further investigation of telaprevir combination therapy in patients with HCV genotype 4 infection is warranted.

Telaprevir activity in treatment-naive patients infected hepatitis C virus genotype 4: a randomized trial

BACKGROUND

This partially blinded, randomized, phase 2a C210 study evaluated the antiviral activity of telaprevir-based regimens in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 4 infection.

METHODS

Twenty-four patients received telaprevir 750 mg every 8 hours for 15 days (T; n = 8), telaprevir in combination with pegylated interferon alfa-2a and ribavirin (Peg-IFN/RBV) for 15 days (TPR; n = 8), or Peg-IFN/RBV plus placebo for 15 days (PR; n = 8), followed by Peg-IFN/RBV for 46 or 48 weeks. The primary objective was to assess the effect of telaprevir on HCV RNA levels.

RESULTS

HCV RNA levels decreased slightly with T and PR; TPR produced substantial, rapid declines. On day 15, median reductions in the HCV RNA load from baseline were -0.77, -4.32, and -1.58 log10 IU/mL for T, TPR, and PR, respectively, and 0 patients in the T group, 1 in the TPR group, and 0 in the PR group had undetectable HCV RNA. Five of 8 patients who received telaprevir monotherapy had viral breakthrough within 15 days of treatment. Adverse event incidence was similar across treatments and comparable with the incidences from previous clinical trials. One patient (in T group) had a serious adverse event (considered unrelated to telaprevir) that led to treatment discontinuation.

CONCLUSIONS

Telaprevir with Peg-IFN/RBV had greater activity than Peg-IFN/RBV treatment or telaprevir monotherapy against HCV genotype 4. Telaprevir was generally safe and well tolerated. Further investigation of telaprevir combination therapy in patients with HCV genotype 4 infection is warranted.

Hepatitis C viral kinetics: the past, present, and future

Mathematical modeling of hepatitis C viral kinetics has been an important tool in understanding hepatitis C virus (HCV) infection dynamics and in estimating crucial in vivo parameters characterizing the effectiveness of HCV therapy. Because of the introduction of direct-acting antiviral agents, there is a need to extend previous models so as to understand, characterize, and compare various new HCV treatment regimens. Here we review recent modeling efforts in this direction.

Equal HIV-1 decay kinetics in HSV-2-infected and HSV-2-uninfected clinical trial participants treated with antiretroviral therapy

Herpes simplex virus-2 increases HIV-1 viral load and may augment HIV-1 transmission probability. To test the hypothesis that lower HIV-1 clearance rates in HSV-2-infected persons may account for this higher HIV-1 viral load, we studied 149 participants from 3 ACTG viral dynamic studies (A315, A5160s, and A5166s). Though HIV-1 viral load was 0.19 logs higher in HSV-2-positive versus HSV-2-negative persons, first and second phase clearance rates during antiretroviral therapy were equal between participants in these 2 groups.

Single nucleotide polymorphism upstream of interleukin 28B associated with phase 1 and phase 2 of early viral kinetics in patients infected with HCV genotype 1

BACKGROUND & AIMS

We studied the relationship between IL28B gene-related SNP rs12979860 and early viral kinetics (day 0-28) during peginterferon and ribavirin treatment, in 173 African Americans (AA) and 188 Caucasian Americans (CA) with HCV genotype 1.

METHODS

We studied the relationship between IL28B 16 gene-related SNP rs12979860 and early viral kinetics (day 0-28) 17 during peginterferon and ribavirin treatment, in 171 African 18 Americans (AA) and 188 Caucasian Americans (CA) with HCV 19 genotype 1.

RESULTS

Compared to non-C/C genotypes, C/C was associated with greater declines in serum HCV RNA during phase 1 (day 0-2), phase 2 (day 7-28), and day 0-28 and higher response (undetected HCV RNA) rates at weeks 4 and 12 in AA and CA. A static phase and increases in HCV RNA from day 2 to 7 were more common in patients with non-C/C genotypes. C/C was also associated with higher week 24, 48, and 72 response rates in CA (p<0.01) but not in AA. At baseline, SNP genotype was the only independent predictor of phase 1; SNP genotype and phase 1 were independent predictors of phase 2 (p<0.001). There were no racial differences in HCV RNA declines during phase 1, day 2-7, phase 2, and day 0-28 with the same SNP genotype. AA with C/C and C/T genotypes had lower week 24, 48, and 72 (SVR) rates than did CA (p=0.03). SNP C/C predicted higher SVR rates in AA and CA with high baseline HCV RNA (≥ 600,000 IU/ml), and in CA with ≥ 1 log(10)IU/ml decrease in HCV RNA from day 0 to 28.

CONCLUSIONS

SNP rs12979860 is strongly associated with both phase 1 and phase 2 HCV RNA kinetics in AA and CA with HCV genotype 1.

IL28B gene polymorphisms and viral kinetics in HIV/hepatitis C virus-coinfected patients treated with pegylated interferon and ribavirin

BACKGROUND

A single nucleotide polymorphism (SNP) upstream of the IL28B gene (rs12979860) predicts sustained virological response (SVR) to peginterferon-ribavirin therapy in chronic hepatitis C patients. There is scarce information regarding the influence of this IL28B SNP on early viral kinetics during therapy, particularly in patients coinfected with HIV, in whom treatment response is lower than in hepatitis C virus (HCV)-monoinfected patients.

METHODS

We selected 196 HIV/HCV-coinfected individuals who had completed a course of peginterferon-ribavirin therapy, and a validated outcome for SVR. Association of IL28B SNPs with rapid, early and end-of-treatment virological responses [rapid virological response (RVR), early virological response (EVR) and end of treatment virological response, respectively] was assessed in univariate and multivariate analyses.

RESULTS

Rate of SVR in the study population was 54%. Frequency of the IL28B CC genotype was 44%. The distribution of HCV genotypes was as follows: HCV-1 57%, HCV-2 1%, HCV-3 30% and HCV-4 12%. Compared to CT/TT, the CC genotype was associated with significantly higher rates of all on-treatment viral outcomes, after adjusting for other predictors of viral response as serum HCV-RNA, HCV genotype and liver fibrosis staging. IL28B CC genotype kept its predictive power of SVR in patients who did not achieve RVR or cEVR. The association between IL28B SNP and viral kinetics and treatment outcomes was significant only for HCV genotypes 1 and 4.

CONCLUSION

IL28B CC genotype is a strong predictor of virological response to therapy in HIV/HCV-coinfected patients. This effect is mediated by an increase in viral clearance during the first 12 weeks of treatment and is mainly seen in patients infected with HCV genotypes 1 and 4.

S-adenosyl methionine improves early viral responses and interferon-stimulated gene induction in hepatitis C nonresponders

BACKGROUND & AIMS

Less than half of patients infected with hepatitis C virus (HCV) achieve sustained viral clearance after pegylated interferon (peginterferon) and ribavirin therapy. S-adenosyl methionine (SAMe) improves interferon signaling in cell culture. We assessed the effect of SAMe on the kinetics of the early antiviral response and interferon signaling in nonresponders to previous antiviral therapy and investigated the mechanisms involved.

METHODS

Nonresponders with HCV genotype 1 were given peginterferon alfa-2a and ribavirin for 2 weeks (course A, baseline/control). After 1 month, patients received SAMe (1600 mg daily) for 2 weeks and then peginterferon and ribavirin for 48 weeks (course B; completed by 21 of 24 patients). Viral kinetics and interferon-stimulated gene (ISG) expression in peripheral blood mononuclear cells (PBMCs) were compared between courses.

RESULTS

The decrease in HCV RNA from 0 to 48 hours (phase 1) was similar with and without SAMe. However, the second phase slope of viral decline was improved with SAMe (course A, 0.11 ± 0.04 log(10) IU/mL/wk; course B, 0.27 ± 0.06; P = .009); 11 patients (53%) achieved an early virological response, and 10 (48%) had undetectable HCV RNA by week 24. Induction of ISGs in PBMCs was significantly greater during course B. In cultured cells, SAMe increased induction of ISGs and the antiviral effects of interferon by increasing STAT1 methylation, possibly affecting STAT1-DNA binding.

CONCLUSIONS

The addition of SAMe to peginterferon and ribavirin improves the early viral kinetics and increases ISG induction in nonresponders to previous therapy. SAMe might be a useful adjunct to peginterferon-based therapies in chronic HCV infection.

A perspective on modelling hepatitis C virus infection

By mathematically describing early hepatitis C virus (HCV) RNA decay after initiation of interferon (IFN)-based antiviral therapy, crucial parameters of the in vivo viral kinetics have been estimated, such as the rate of production and clearance of free virus, and the rate of loss of infected cells. Furthermore, by suggesting mechanisms of action for IFN and ribavirin mathematical modelling has provided a means for evaluating and optimizing treatment strategies. Here, we review recent modelling developments for understanding complex viral kinetics patterns, such as triphasic HCV RNA declines and viral rebounds observed in patients treated with pegylated interferon and ribavirin. Moreover, we discuss new modelling approaches developed to interpret the viral kinetics observed in clinical trials with direct-acting antiviral agents, which induce a rapid decline of wild-type virus but also engender a higher risk for emergence of drug-resistant variants. Lastly, as in vitro systems have allowed a better characterization of the virus lifecycle, we discuss new modelling approaches that combine the intracellular and the extracellular viral dynamics.

Meta-analysis of hepatitis C virus vaccine efficacy in chimpanzees indicates an importance for structural proteins

BACKGROUND & AIMS

Studies in patients and chimpanzees that spontaneously cleared hepatitis C virus (HCV) infections demonstrated that natural immunity to the virus is induced during primary infections and that this immunity can be cross protective. These discoveries led to optimism about prophylactic HCV vaccines, and several studies were performed in chimpanzees, although most included fewer than 6 animals. To draw meaningful conclusions about the efficacy of HCV vaccines in chimpanzees, we performed statistical analyses of data from previously published studies from different groups.

METHODS

We performed a meta-analysis that compared parameters among naïve (n = 63), vaccinated (n = 53), and rechallenged (n = 36) animals, including peak RNA titer postchallenge, time points of peak RNA titer, duration of viremia, and proportion of persistent infections.

RESULTS

Each vaccination study induced immune responses that were effective in rapidly controlling HCV replication. Levels of induced T-cell responses did not indicate vaccine success. There was no reduction in the rate of HCV persistence in vaccinated animals, compared with naïve animals, when nonstructural proteins were included in the vaccine. Vaccines that contained only structural proteins had clearance rates that were significantly higher than vaccines that contained nonstructural components (P = .015).

CONCLUSIONS

The inclusion of nonstructural proteins in HCV vaccines might be detrimental to protective immune responses, and/or structural proteins might activate T-cell responses that mediate viral clearance.

Novel mechanism of antibodies to hepatitis B virus in blocking viral particle release from cells

Antibodies are thought to exert antiviral activities by blocking viral entry into cells and/or accelerating viral clearance from circulation. In particular, antibodies to hepatitis B virus (HBV) surface antigen (HBsAg) confer protection, by binding circulating virus. Here, we used mathematical modeling to gain information about viral dynamics during and after single or multiple infusions of a combination of two human monoclonal anti-HBs (HepeX-B) antibodies in patients with chronic hepatitis B. The antibody HBV-17 recognizes a conformational epitope, whereas antibody HBV-19 recognizes a linear epitope on the HBsAg. The kinetic profiles of the decline of serum HBV DNA and HBsAg revealed partial blocking of virion release from infected cells as a new antiviral mechanism, in addition to acceleration of HBV clearance from the circulation. We then replicated this approach in vitro, using cells secreting HBsAg, and compared the prediction of the mathematical modeling obtained from the in vivo kinetics. In vitro, HepeX-B treatment of HBsAg-producing cells showed cellular uptake of antibodies, resulting in intracellular accumulation of viral particles. Blocking of HBsAg secretion also continued after HepeX-B was removed from the cell culture supernatants.

CONCLUSION

These results identify a novel antiviral mechanism of antibodies to HBsAg (anti-HBs) involving prolonged blocking of the HBV and HBsAg subviral particles release from infected cells. This may have implications in designing new therapies for patients with chronic HBV infection and may also be relevant in other viral infections.

Ribavirin improves early responses to peginterferon through improved interferon signaling

BACKGROUND & AIMS

The therapeutic mechanisms of ribavirin for hepatitis C are unclear. Microarray analyses have shown that ribavirin increases induction of interferon-stimulated genes. We evaluated viral kinetics, serum cytokine expression, and viral mutagenesis during early stages of peginterferon therapy with and without ribavirin.

METHODS

Fifty patients with chronic hepatitis C virus (HCV) infection genotype 1 were randomly assigned to groups that were given peginterferon alpha-2a, with or without ribavirin, for 4 weeks; all patients then received an additional 44 weeks of combination therapy. First- and second-phase viral kinetics were evaluated. Serum levels of interferon-gamma-inducible protein-10 (IP10), monokine induced by interferon-gamma, and monocyte chemoattractant protein 1 were quantified as measures of the interferon-stimulated genes response. NS5A and NS5B were partially sequenced, and mutation rates were calculated.

RESULTS

The first-phase decrease in HCV RNA was similar between groups. Patients who received ribavirin had a more rapid second-phase decrease, compared with patients who did not receive ribavirin-particularly those with an adequate first-phase decrease (0.61 vs 0.35 log10 IU/mL/week; P = .018). At 12 hours, fold induction of serum IP10 was higher in patients given the combination therapy than those given peginterferon only (7.6- vs 3.8-fold; P = .01); however, the difference was greatest in patients with an adequate first-phase decrease in HCV RNA. IP10-induction correlated with first- and second-phase kinetics and with ribavirin serum concentrations on day 3. HCV mutation rates were similar between groups.

CONCLUSIONS

Ribavirin improves the kinetics of the early response to therapy in patients with an adequate initial response to peginterferon. Induction of interferon-stimulated cytokines correlates with viral kinetics following ribavirin therapy, suggesting that ribavirin promotes interferon signaling.

Modelling the kinetics of hepatitis C virus RNA decline over 4 weeks of treatment with pegylated interferon alpha-2b

Viral kinetic models for hepatitis C virus (HCV) have generally assumed that the effectiveness of therapy in blocking virion production, epsilon, is constant. However, with pegylated interferon alpha-2b (PEG-IFN) given weekly, there are significant changes in drug concentration between doses that may lead to changes in drug effectiveness and viral rebounds towards the end of the dosing interval. Here we investigate the effects of using a model that assumes a constant effectiveness for studies involving PEG-IFN. We simulated PEG-IFN treatment in a population of 294 computer simulated 'patients', each characterized by a different set of pharmacokinetic and pharmacodynamic parameters. We then sampled the simulated treatment data over 4 weeks with a schedule similar to that used in viral kinetic studies, and fitted a viral kinetic model assuming constant drug effectiveness, the CE model, to that data. Although the CE model was able to fit to the data well in most cases, the parameter estimates obtained scattered widely both above and below the true values. Thus, this model is less useful to analyse HCV RNA data during therapy with PEG-IFN than with standard IFN given daily. With PEG-IFN accurate estimation of viral dynamic parameters necessitates concomitant measurements of serum viral load and drug concentration.

Modeling hepatitis C virus dynamics: liver regeneration and critical drug efficacy

Mathematical models for hepatitis C viral (HCV) RNA kinetics have provided a means of evaluating the antiviral effectiveness of therapy, of estimating parameters such as the rate of HCV RNA clearance, and they have suggested mechanism of action against HCV for both interferon and ribavirin. Nevertheless, the model that was originally formulated by Neumann et al. [1998. Hepatitis C viral dynamics in vivo and the antiviral efficacy of interferon-alpha therapy. Science 282 (5386), 103-107] is unable to explain all of the observed HCV RNA profiles under treatment e.g., a triphasic viral decay and a viral rebound to baseline values after the cessation of therapy. Further, the half-life of productively HCV-infected cells, estimated from the second phase HCV RNA decline slope, is very variable and sometimes zero with no clear understanding of why. We show that extending the original model by including hepatocyte proliferation yields a more realistic model without any of these deficiencies. Further, we define and characterize a critical drug efficacy, such that for efficacies above the critical value HCV is ultimately cleared, while for efficacies below it, a new chronically infected viral steady-state level is reached.