Factors Affecting the Virological Response Among Chronic Hepatitis C Virus Patients in Yemen

Hepatitis C virus (HCV) infection is increasingly seen as a major public health problem, threat, and concern worldwide. In Yemen about 1.7% of the population is infected with chronic hepatitis C. This study aimed to detect the predictors for response to pegylated interferon and ribavirin (Peg-IFN/RBV) in chronic HCV Yemeni patients. The study was conducted on 100 patients with chronic HCV who received Peg-IFN/RBV in the 48th Military Hospital in Sana'a Yemen, from 2011 to 2013. All patients were subjected to complete history taking, thorough clinical examinations, routine laboratory investigation, and abdominal ultrasonography. The HCV RNA was assessed at week 72 of treatment to detect whether the patient achieved sustained virological response (SVR). The SVR was achieved in 64% of the samples. Age above 40, Khat chewing, and obesity were the sociodemographic factors that predict good response for Peg-IFN/RBV combined therapy. Platelet count, alpha feto-protein (AFP), aspartate transaminase (AST), and alanine transaminase (ALT) levels were the basic laboratory investigations that gave favorable response. Significant predictors of sustained response included: older than 40 years (OR = 0.136, P = 0.042), Khat chewer (OR = 0.016, P = 0.008), body mass index (BMI) (OR = 0.055, P = 0.029) and increase in fasting blood glucose (OR = 0.925, P = 0.004), alkaline phosphatase (OR = 0.969, P = 0.001), total and bilirubin (OR = 0.058, P = 0.017), AST (OR = 1.033, P = 0.002), and albumin (OR = 6.490, P = 0.021). Studying the independent variables of response, we revealed that male gender, BMI, ALT >40, AFP >10, viremia >600, and hemoglobin and thyroid stimulating hormone (TSH) levels are variables associated with failure of end of treatment response (ETR) and SVR.

Pegylated interferon alpha 2a for the treatment of hepatitis C virus infection

INTRODUCTION

Treatments for hepatitis C virus (HCV) infection have advanced rapidly in the last decade. Pegylated interferon alpha 2a (PEG-IFN alpha 2a) alone, in combination with ribavirin and with or without direct acting antivirals (DAAs) is modestly effective in the treatment of chronic HCV infection. Areas covered: The review describes the chemistry, pharmacokinetic and pharmacodynamic properties, clinical efficacy, safety and drug-drug interaction profiles of PEG-IFN alpha 2a. Expert opinion: Despite the availability of DAAs and its formidable toxicity profile, PEG-IFN alpha 2a retains a role for the treatment of acute HCV and chronic HCV infection in resource limited settings and for end-stage renal disease patients and others who cannot access DAAs or are DAA-ineligible. Knowledge of pharmacogenetic profiles which favor successful treatment outcomes with IFN-based therapies may allow for selection of best candidates for the regimen.

Interferon-Alpha Reduces Human Hippocampal Neurogenesis and Increases Apoptosis via Activation of Distinct STAT1-Dependent Mechanisms

BACKGROUND

In humans, interferon-α treatment for chronic viral hepatitis is a well-recognized clinical model for inflammation-induced depression, but the molecular mechanisms underlying these effects are not clear. Following peripheral administration in rodents, interferon-α induces signal transducer and activator of transcription-1 (STAT1) within the hippocampus and disrupts hippocampal neurogenesis.

METHODS

We used the human hippocampal progenitor cell line HPC0A07/03C to evaluate the effects of 2 concentrations of interferon-α, similar to those observed in human serum during its therapeutic use (500 pg/mL and 5000 pg/mL), on neurogenesis and apoptosis.

RESULTS

Both concentrations of interferon-α decreased hippocampal neurogenesis, with the high concentration also increasing apoptosis. Moreover, interferon-α increased the expression of interferon-stimulated gene 15 (ISG15), ubiquitin-specific peptidase 18 (USP18), and interleukin-6 (IL-6) via activation of STAT1. Like interferon-α, co-treatment with a combination of ISG15, USP18, and IL-6 was able to reduce neurogenesis and enhance apoptosis via further downstream activation of STAT1. Further experiments showed that ISG15 and USP18 mediated the interferon-α-induced reduction in neurogenesis (potentially through upregulation of the ISGylation-related proteins UBA7, UBE2L6, and HERC5), while IL-6 mediated the interferon-α-induced increase in apoptosis (potentially through downregulation of aquaporin 4). Using transcriptomic analyses, we showed that interferon-α regulated pathways involved in oxidative stress and immune response (e.g., Nuclear Factor (erythroid-derived 2)-like 2 [Nrf2] and interferon regulatory factor [IRF] signaling pathway), neuronal formation (e.g., CAMP response element-binding protein [CREB] signaling), and cell death regulation (e.g., tumor protein(p)53 signaling).

CONCLUSIONS

We identify novel molecular mechanisms mediating the effects of interferon-α on the human hippocampus potentially involved in inflammation-induced neuropsychiatric symptoms.

Quantitative Detection of PEGylated Biomacromolecules in Biological Fluids by NMR

The accumulation, biodistribution, and clearance profiles of therapeutic agents are key factors relevant to their efficacy. Determining these properties constitutes an ongoing experimental challenge. Many such therapeutics, including small molecules, peptides, proteins, tissue scaffolds, and drug delivery vehicles, are conjugated to poly(ethylene glycol) (PEG) as this improves their bioavailability and in vivo stability. We demonstrate here that (1)H NMR spectroscopy can be used to quantify PEGylated species in complex biological fluids directly, rapidly, and with minimal sample preparation. PEG bears a large number of spectroscopically equivalent protons exhibiting a narrow NMR line width while resonating at a (1)H NMR frequency distinct from most other biochemical signals. We demonstrate that PEG provides a robust signal allowing detection of concentrations as low as 10 μg/mL in blood. This PEG detection limit is lowered by another order of magnitude when background proton signals are minimized using (13)C-enriched PEG in combination with a double quantum filter to remove (1)H signals from non-(13)C-labeled species. Quantitative detection of PEG via these methods is shown in pig blood and goat serum as examples of complex biological fluids. More practically, we quantify the blood clearance of (13)C-PEG and PEGylated-BSA (bovine serum albumin) following their intravenous injection in live rats. Given the relative insensitivity of line width to PEG size, we anticipate that the biodistribution and clearance profiles of virtually any PEGylated biomacromolecule from biological fluid samples can be routinely measured by (1)H NMR without any filtering or treatment steps.

Predictors of Virological Response in 3,235 Chronic HCV Egyptian Patients Treated with Peginterferon Alpha-2a Compared with Peginterferon Alpha-2b Using Statistical Methods and Data Mining Techniques

Despite the appearance of new oral antiviral drugs, pegylated interferon (PEG-IFN)/RBV may remain the standard of care therapy for some time, and several viral and host factors are reported to be correlated with therapeutic effects. This study aimed to reveal the independent variables associated with failure of sustained virological response (SVR) to PEG-IFN alpha-2a versus PEG-IFN alpha-2b in treatment of naive chronic hepatitis C virus (HCV) Egyptian patients using both statistical methods and data mining techniques. This retrospective cohort study included 3,235 chronic hepatitis C patients enrolled in a large Egyptian medical center: 1,728 patients had been treated with PEG-IFN alpha-2a plus ribavirin (RBV) and 1,507 patients with PEG-IFN alpha-2b plus RBV between 2007 and 2011. Both multivariate analysis and Reduced Error Pruning Tree (REPTree)-based model were used to reveal the independent variables associated with treatment response. In both treatment types, alpha-fetoprotein (AFP) >10 ng/mL and HCV viremia >600 × 10(3) IU/mL were the independent baseline variables associated with failure of SVR, while male gender, decreased hemoglobin, and thyroid-stimulating hormone were the independent variables associated with good response (P < 0.05). Using REPTree-based model showed that low AFP was the factor of initial split (best predictor) of response for either PEG-IFN alpha-2a or PEG-IFN alpha-2b (cutoff value 8.53, 4.89 ng/mL, AUROC = 0.68 and 0.61, P = 0.05). Serum AFP >10 ng/mL and viral load >600 × 10(3) IU/mL are variables associated with failure of response in both treatment types. REPTree-based model could be used to assess predictors of response.

Differential antiviral effects of pegylated interferon-α2a and pegylated interferon-α2b in chronic hepatitis C

BACKGROUND AND OBJECTIVES

Pegylated interferon (peg-IFN)-α2a and -α2b show different pharmacokinetic properties but are used interchangeably for hepatitis C treatment in traditional dual combinations and with newer agents. We assessed whether peg-IFN antiviral effects vary with peg-IFN subtype, affecting viral response in a differential manner.

METHODS

Chronic hepatitis C patients treated with ribavirin combined with peg-IFN-α2a (N = 109) or -α2b (N = 114) were studied. Hepatitis C virus RNA quantitation was performed by Cobas TaqMan 5 min before treatment start and subsequently after 48/72 h and 7, 14, 28 and 90 days. Antiviral effect was assessed in terms of viraemia changes over treatment. Histology grading and staging, interleukin-28B (IL28B) status and baseline viral genotype, alanine aminotransferase, gamma glutamyltransferase and glucose were analysed.

RESULTS

Viraemia decline after 48/72 h and 7 days was significantly greater with peg-IFN-α2b (1.96 and 2.12 vs 1.49 and 1.20 log10 IU/mL with peg-IFN-α2a; p < 0.001). Differences were of larger extent in patients with advanced fibrosis (p = 0.002), genotype 1 infection (p = 0.002) and CT/TT genotypes of IL28B (p = 0.001). A rebound in viral load was observed significantly more often after the first dose in patients treated with peg-IFN-α2b (78 vs 28 % in those with peg-IFN-α2a; p = 0.0001). Differences between peg-IFNs disappeared by day 28 of treatment.

CONCLUSION

There are significant pharmacodynamic differences between peg-IFN-α2a and -α2b in the early phase of chronic hepatitis C treatment. The greater early viral decline observed with peg-IFN-α2b was essentially confined to 'difficult to treat' patients. Whether this could affect response-guided treatment decision making, as well as triple drug regimens, needs to be assessed.

The clinical effectiveness and cost-effectiveness of peginterferon alfa and ribavirin for the treatment of chronic hepatitis C in children and young people: a systematic review and economic evaluation

BACKGROUND

Optimal therapy for children with chronic hepatitis C is unclear. Two treatment regimens are currently licensed in children.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of peginterferon alfa-2a (Pegasys®, Roche) and peginterferon alfa-2b [ViraferonPeg®, Merck Sharp & Dohme (MSD)] in combination with ribavirin (RBV), within their licensed indications, for the treatment of chronic hepatitis C virus (HCV) in children and young people aged 3-17 years.

DATA SOURCES

Twelve electronic bibliographic databases, including The Cochrane Library, MEDLINE and EMBASE, were searched from inception to November 2012. Bibliographies of retrieved papers, key hepatitis C websites and symposia and manufacturers' submissions to the National Institute for Health and Care Excellence were also searched, and clinical experts were contacted.

REVIEW METHODS

Systematic reviews of clinical effectiveness and cost-effectiveness were conducted, including studies of health-related quality of life (HRQoL), following standard guidelines to ensure methodological rigour. Clinical effectiveness studies were included if they were in children and young people aged 3-17 years with chronic compensated HCV of any severity, including those with human immunodeficiency virus co-infection and those who were treatment naive or had been previously treated. Eligible interventions were peginterferon alfa-2a or peginterferon alfa-2b, each in combination with RBV, compared against best supportive care (BSC) or against each other, and study designs were randomised controlled trials (RCTs) or non-RCTs, or uncontrolled cohort studies. Outcomes included sustained virological response (SVR) and adverse events. Previously published Markov state-transition economic models of chronic HCV in adults were adapted to estimate the cost-effectiveness of peginterferon alfa-2a and -2b (in combination with RBV), compared with BSC and with one another in children. The model extrapolated the impact of SVR on life expectancy, quality-adjusted life expectancy and lifetime costs. Uncertainty was explored through probabilistic and deterministic sensitivity analyses.

RESULTS

Seven studies [two peginterferon alfa-2a and RBV (Copegus®, Roche), and five peginterferon alfa-2b and RBV (Rebetol®, MSD)] were included in the review of clinical effectiveness. Six were single-arm cohort studies and one was a RCT for which only those data for a single arm met the inclusion criteria. Overall, the studies were relatively small and of generally poor quality. SVR rates ranged from 53% to 66% (peginterferon alfa-2a) and 29% to 75% (peginterferon alfa-2b) (49% to 65% if excluding two studies with very small sample sizes). Rates of non-response and relapse were variable and adverse events were generally mild. No studies of cost-effectiveness or HRQoL in children and young people met the inclusion criteria. HRQoL, utilities and costs of treatment were therefore taken from studies of adults with chronic HCV. From this model, peginterferon alfa (-2a or -2b) in combination with RBV was more effective and had lower lifetime costs than BSC. Peginterferon alfa-2a had slightly lower lifetime costs and higher quality-adjusted life-years than peginterferon alfa-2b; therefore, peginterferon alfa-2b was dominated by peginterferon alfa-2a. Results were robust to changes in the sensitivity analyses.

LIMITATIONS

There were few good quality studies and parameter data had to be taken from adult studies, which is a limitation of the work.

CONCLUSIONS

Treatment of children and young people with peginterferon (alfa-2a or -2b) and RBV may be an effective therapy. Results from the independent Markov model suggest that peginterferon (alfa-2a or -2b) in combination with RBV is cost-effective compared with BSC. However, the available evidence is of poor quality. Future research into the impact of these treatments on growth and quality of life in children and young people is recommended.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002743.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Viral hepatitis C therapy: pharmacokinetic and pharmacodynamic considerations

Chronic hepatitis C is a global health problem. To prevent or reduce complications, the hepatitis C virus (HCV) infection needs to be eradicated. There have been several developments in treating these patients since the discovery of the virus. As of 1 January 2014, the drugs that are approved for treatment of chronic HCV infection are peginterferon-α, ribavirin, boceprevir, telaprevir, simeprevir and sofosbuvir. In this review we provide an overview of the clinical pharmacokinetic characteristics of these agents by describing their absorption, distribution, metabolism and excretion. In the pharmacodynamic part we summarize what is known about the relationships between the pharmacokinetics of each drug and efficacy or toxicity. We briefly discuss the pharmacokinetics and pharmacodynamics of chronic hepatitis C treatment in special patient populations, such as patients with liver cirrhosis, renal insufficiency or HCV/HIV coinfection, and children. With this knowledge, physicians, pharmacists, nurse practitioners, etc. should be educated to safely and effectively treat HCV-infected patients.

A pharmacokinetic-viral kinetic model describes the effect of alisporivir as monotherapy or in combination with peg-IFN on hepatitis C virologic response

Alisporivir is a cyclophilin inhibitor with demonstrated in vitro and in vivo activity against hepatitis C virus (HCV). We estimated the antiviral effectiveness of alisporivir alone or in combination with pegylated interferon (peg-IFN) in 88 patients infected with different HCV genotypes treated for 4 weeks. The pharmacokinetics of the two drugs were modeled and used as driving functions for the viral kinetic model. Genotype was found to significantly affect peg-IFN effectiveness (ɛ = 86.3 and 99.1% for genotypes 1/4 and genotypes 2/3, respectively, P < 10(-7)) and the loss rate of infected cells (δ = 0.22 vs. 0.39 per day in genotype 1/4 and genotype 2/3 patients, respectively, P < 10(-6)). Alisporivir effectiveness was not significantly different across genotypes and was high for doses ≥600 mg q.d. We simulated virologic responses with other alisporivir dosing regimens in HCV genotype 2/3 patients using the model. Our predictions consistently matched the observed responses, demonstrating that this model could be a useful tool for anticipating virologic response and optimizing alisporivir-based therapies.

New antiviral therapies for chronic hepatitis C

Chronic hepatitis C is an important health issue worldwide. The current standard therapy is based on a combination of pegylated-interferon (pegIFN) and ribavirin (RBV), but this treatment leads to only ~50% sustained virological response (SVR) in patients with HCV genotype 1 and high viral loads, who were mostly null-responders or relapsers. Among HCV genotypes other than HCV genotype 1, especially HCV genotype 4 patients show only 40-70% SVR by this treatment. Although new drugs also depend on the combination of pegIFN and RBV, it appears that these drugs improve not only rapid virological response (RVR) but also early virological response, leading to SVR in these patients. In the near future, we predict higher SVR rates in chronic hepatitis C patients treated with these new drugs.

Distinct Hepatitis C virus Kinetics in HIV-Infected Patients Treated with Ribavirin plus Either Pegylated Interferon α2a or α2b

Background

Pegylated interferon (PEG-IFN) α2a and α2b differ in their pharmacokinetic properties, which might have an effect on their antiviral effects against hepatitis C virus (HCV). Differences between PEG-IFN-α molecules could be more pronounced in HIV-coinfected individuals, in whom response to HCV treatment is impaired.

Methods

All HCV–HIV-coinfected patients included in PRESCO and EXTENT trials recruited at one referral centre were retrospectively analysed. In both trials, ribavirin (RBV) 1,000–1,200 mg/day was prescribed together with standard doses of PEG-IFN-α2a or -α2b. The attainment of serum HCV RNA <10 IU/ml at weeks 4, 12 and 24 was assessed. On-treatment analyses were made to estimate the intrinsic potency of PEG-IFN-α2a versus -α2b.

Results

A total of 218 patients were examined, 138 on PEG-IFN-α2a and 80 on PEG-IFN-α2b. Baseline characteristics were comparable in both groups. Undetectable serum HCV RNA at weeks 4, 12 and 24 was more frequently attained using PEG-IFN-α2a than -α2b (45% versus 27% [ P=0.02]; 65% versus 45% [ P=0.01]; and 75% versus 55% [ P=0.01], respectively), regardless of HCV genotype. Plasma RBV levels did not differ between groups. In multivariate analysis, HCV genotypes 2/3 (odds ratio [OR] 12.5; 95% confidence interval [95% CI] 3.45–33.33; P<0.001), use of zidovudine (OR 0.30; 95% CI 0.11–0.85; P=0.02) and treatment with PEG-IFN-α2a (OR 2.12; 95% CI 1.02–4.54; P=0.04) were independent predictors of undetectable HCV RNA at week 24. Conversely, the incidence of serious adverse events was more common with PEG-IFN-α2a than -α2b (13.2% versus 3.6%; P=0.018).

Conclusions

The antiviral effect against HCV seems to be greater for PEG-IFN-α2a than -α2b in the HIV setting. A shorter half-life of PEG-IFN-α2b could explain this finding.