Management of hepatitis C virus infection recurrence after liver transplantation: an overview

Discovery of Novel HCV NS5B polymerase inhibitor, 2-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)-N-(2-fluorobenzyl)acetamide via molecular docking and experimental approach

Hepatitis C Virus (HCV) is a viral infection posing a severe global threat that left untreated progresses to end-stage liver disease, including cirrhosis and hepatocellular carcinoma (HCC). Moreover, no prophylactic approach exists so far enabling its prevention. The NS5B polymerase holds special significance as the target of intervention against HCV infection. The current study kindles benzothiazine derivatives against HCV NS5B polymerase through in silico and experimental approaches. Following docking, the compound 2-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)-N-(2-fluorobenzyl)acetamide was revealed to form effective binding interaction in the proposed site of HCV NS5B with a score of -10 kcal/mol and subsequently was deciphered through molecular dynamics (MD) simulation study which indicated interaction of residues TYR_382, VAL_381 and HIS_467 through hydrophobic interaction and two residues such as GLU_202 and LYS_209 contributed in the formation of water bridges. The subsequent in silico pharmacological analysis revealed its safe drug profile. The cytotoxicity activity of compound 6c indicated to be non-toxic in HepG2 cells at concentration ranges from 0.001-1.0 µmol/L with >80% cell viability and diminished expression of the HCV NS5B to 98% at the dose of 1.0 µmol/L and 90% at 0.5µmol/L. Thus the hit compound 6c might be a potent NS5B polymerase inhibitor required to be validated further through in vivo and preclinical studies.

Treatment of early stage chronic hepatitis C virus infection

INTRODUCTION

Treatment of Hepatitis C Virus (HCV) with direct acting antivirals (DAAs) is able to achieve the cure of infection in almost the totality of patients, independently of the characteristics of the individual and the virus, using short treatment schedules, and without the need of ribavirin. The high cost of DAAs is the main limiting factor for universal treatment of HCV. However, there is a strong evidence that treatment of infection at the early stage of disease may be the most rewarding approach. Areas covered: This review evaluates the aspects underlying the benefit of treating chronic HCV infection at the early stage of disease. It outlines the considerations that have to be taken into account when planning treatment in patients with HCV and minimal liver disease, assessing the positive reflex of viral eradication on several HCV-associated extra-hepatic conditions such as the risk of lymphoma, insulin-resistance and glycaemic control, and renal function. Lastly, it also covers the improvement of patients' quality of life and the pharmaco-economic aspects associated with early treatment. Expert commentary: Treatment of patients with HCV and minimal liver disease is associated with a beneficial, pleiotropic effect of viral eradication that goes beyond the simplistic consideration of the improvement in liver disease-related outcomes.

Hepatitis C virus: Morphogenesis, infection and therapy

Hepatitis C virus (HCV) is a major cause of liver diseases including liver cirrhosis and hepatocellular carcinoma. Approximately 3% of the world population is infected with HCV. Thus, HCV infection is considered a public healthy challenge. It is worth mentioning, that the HCV prevalence is dependent on the countries with infection rates around 20% in high endemic countries. The review summarizes recent data on HCV molecular biology, the physiopathology of infection (immune-mediated liver damage, liver fibrosis and lipid metabolism), virus diagnostic and treatment. In addition, currently available in vitro, ex vivo and animal models to study the virus life cycle, virus pathogenesis and therapy are described. Understanding of both host and viral factors may in the future lead to creation of new approaches in generation of an efficient therapeutic vaccine.

Therapy with Direct-Acting Antiviral Agents for Hepatitis C-Related Liver Cirrhosis

Chronic hepatitis C virus (HCV) infection may eventually lead to liver cirrhosis (LC), a condition associated with a high risk of liver failure and hepatocellular carcinoma. Although interferon (IFN)-based therapy has made substantial contributions to the management of HCV-infected patients, this therapy has limitations for LC patients in terms of eligibility, tolerability, relatively low and high rates of sustained virological response (SVR), and serious adverse events. Therapy with newly developed direct-acting antiviral agents (DAAs) can overcome these limitations in IFN-based therapy. Recent phase 3 trials have demonstrated that DAA therapy achieved high SVR rates (more than 90% for genotype 1; 80% to 90% for genotype 2; 60% to 70% for genotype 3) for compensated LC patients, with high tolerability and relatively low rates of serious adverse events. Furthermore, trials have suggested that DAA therapy can be used for the treatment of decompensated LC patients as well as pretransplant and posttransplant LC patients. In this article, we review the current status of DAA therapy for HCV-related LC patients.

Future of liver disease in the era of direct acting antivirals for the treatment of hepatitis C

Hepatitis C virus (HCV) infection has been a global health problem for decades, due to the high number of infected people and to the lack of effective and well-tolerated therapies. In the last 3 years, the approval of new direct acting antivirals characterized by high rates of virological clearance and excellent tolerability has dramatically improved HCV infection curability, especially for patients with advanced liver disease and for liver transplant recipients. Long-term data about the impact of the new direct acting antivirals on liver fibrosis and liver disease-related outcomes are not yet available, due to their recent introduction. However, previously published data deriving from the use of pegylated-interferon and ribavirin lead to hypothesizing that we are going to observe, in the future, a reduction in mortality and in the incidence of hepatocellular carcinoma, as well as a regression of fibrosis for people previously affected by hepatitis C. In the liver transplant setting, clinical improvement has already been described after treatment with the new direct acting antivirals, which has often led to patients delisting. In the future, this may hopefully reduce the gap between liver organ request and availability, probably expanding liver transplant indications to other clinical conditions. Therefore, these new drugs are going to change the natural history of HCV-related liver disease and the epidemiology of HCV infection worldwide. However, the global consequences will depend on treatment accessibility and on the number of countries that could afford the use of the new direct acting antivirals.

[Topical problems of antiviral therapy for chronic hepatitis C]

Antiviral therapy using interferon-free regimens for chronic hepatitis C (CHC) is being more frequently practiced by hepatologists due to the high efficiency of a short treatment cycle and the lowest rate of adverse events. The review discusses the most topical problems that will present themselves in practicing hematologists when treating patients with CHC under the present-day conditions. The use of direct-acting antiviral drugs requires knowledge and skills for physicians to orient themselves in the list of these drugs to create their based regimens, the efficiency and safety of which are proven in the context of evidence-based medicine. The review gives data on the efficiency and safety of 3D therapy for CHC according to the baseline characteristics of patients.

Management of hepatitis C infection before and after liver transplantation

Chronic hepatitis C (CHC) is the most common indication for liver transplantation (LT). Aggressive treatment of hepatitis C virus (HCV) infection before cirrhosis development or decompensation may reduce LT need and risk of HCV recurrence post-LT. Factors associated with increased HCV risk or severity of recurrence include older age, immunosuppression, HCV genotype 1 and high viral load at LT. HCV recurrence post-LT leads to accelerated liver disease and cirrhosis development with reduced graft and patient survival. Currently, interferon (IFN)-based regimens can be used in dual-agent regimens with ribavirin, in triple-agent antiviral strategies with direct-acting antivirals (e.g., protease inhibitors telaprevir or boceprevir), or before transplant in compensated patients to reduce HCV viral load to prevent or reduce the risk of post-LT recurrence and complications; they cannot be used in patients with decompensated cirrhosis. IFN-based regimens are used in less than half of HCV-infected patients waiting for LT due to extremely low efficacy and poor tolerability. However, antiviral therapy is indicated after LT in patients with histologically confirmed CHC despite tolerability issues. Improvements in side effect management have increased survival in patients achieving therapeutic targets. HCV treatment pre- and post-LT results in significant health care costs especially when lack of efficacy leads to disease worsening, although studies have shown sofosbuvir treatment before LT vs conventional post-LT dual antiviral is cost effective. The suboptimal efficacy and tolerability of IFN-based therapies, plus the significant economic burden, means the need for effective and well tolerated IFN-free anti-HCV therapy for pre- and post-LT remains high.

The impact of diabetes mellitus and glycemic control on clinical outcomes following liver transplant for hepatitis C

Hepatitis C is the leading indication for liver transplantation in the USA and recurrence is universal. The impact of preexisting diabetes, new-onset diabetes after transplant (NODAT), and glycemic control on fibrosis progression has not been studied. This retrospective longitudinal cohort study included adult liver recipients with hepatitis C transplanted between 2000 and 2011. Patients were divided into three groups: preexisting diabetes (n = 41), NODAT (n = 59), and no diabetes (n = 103). Patients with preexisting diabetes (70%) or NODAT (59%) were more likely to develop hepatitis C recurrence (≥stage 1 fibrosis), as compared to non-diabetics (36%, p = 0.006). There was also a trend toward a higher incidence of at least Stage 2 fibrosis (36% and 48% vs. 23%, respectively; p = 0.063). Patients with tight glycemic control had a lower rate of Stage 2 fibrosis development (78% vs. 60%, p = 0.027), while those with good control (<150 mg/dL) also had lower rates of Stage 2 fibrosis (84% vs. 62%, p = 0.004). Multivariable analysis verified a decreased rate of recurrence for patients with blood glucose <138 mg/dL (p = 0.021), after controlling for confounders. These results demonstrate that diabetes is strongly associated with an increased risk of hepatitis C virus-related fibrosis development and glycemic control may reduce the risk and severity of recurrence.

Synthetic anti-lipopolysaccharide peptides and hepatitis C virus infection

INTRODUCTION

Hepatitis C virus (HCV) infection is a leading cause of cirrhosis and hepatocellular carcinoma. Although antiviral therapy has been markedly improved by the licensing of direct-acting antivirals, safety, resistance, high costs and difficult-to-treat patients remain important challenges.

AREAS COVERED

This article focuses and comments on the recent development of synthetic anti-lipopolysaccharide peptides (SALPs) which bind to highly sulfated glycosaminoglycan/heparan sulfate (HS) on cell surface. HS serves as a primary docking site for several viruses to their respective host cells before the viruses interact with their cell surface receptor(s). In vitro studies have shown that SALPs inhibit entry of HCV without cell toxicity.

EXPERT OPINION

SALPs prevent viral infection in cell culture model systems. Treatment studies of established HCV infection in cell culture models as well as proof-of-concept and safety studies in animal models are needed to evaluate their potential for drug development. The mechanism of action of SALPs as entry inhibitors suggests a potential application for HCV-infected patients to prevent reinfection of the liver graft in liver transplantation. Potential limitations may include high doses to obtain an antiviral effect and a target which is widely expressed and has a key function in cell physiology.

Telaprevir-based triple therapy in liver transplant patients with hepatitis C virus: a 12-week pilot study providing safety and efficacy data

After liver transplantation (LT), the management of recurrent hepatitis C virus (HCV) infections still remains a major challenge. In HCV genotype 1 patients not undergoing transplantation, the introduction of protease inhibitor (PI)-based regimens has increased the sustained virological response rate significantly. This pilot study investigated both the safety and efficacy of telaprevir (TVR)-based triple therapy in HCV-infected LT patients with a special emphasis on drug-drug interactions between immunosuppressants and PIs. Safety and efficacy data were gathered for 12 weeks for 9 HCV-infected LT patients who were treated with a combination of TVR, pegylated interferon, and ribavirin (RBV) in parallel with immunosuppressive drugs such as tacrolimus (TAC; n = 4), cyclosporine A (CSA; n = 4), and sirolimus (SIR; n = 1). Seven of the transplant patients completed the 12 weeks of triple therapy. At week 4, 4 of the patients were found to be HCV RNA-negative, and importantly, 8 were found to be negative at week 12. During the 12-week course of triple therapy, short-term measurements of immunosuppressant trough levels required individual dose reductions in all patients (CSA, 2.5-fold; SIR, 7-fold; and TAC, 22-fold). Furthermore, two-thirds of the patients exhibited hematological side effects requiring RBV dose reductions, the administration of erythropoietin, or even blood transfusions. In conclusion, this pilot study provides evidence showing that TVR-based triple therapy is effective within the first 4 to 12 weeks in LT patients suffering from HCV genotype 1 recurrence, and it also provides evidence showing that drug-drug interactions between TVR and immunosuppressants can be handled appropriately through the close monitoring of trough levels and adequate dosage adjustments.

Measurement and clinical significance of interleukin 28B in hepatitis C virus-infected liver transplant patients

One-third of the liver transplantations are performed because of hepatitis C cirrhosis all over the world and also in Hungary. The recurrence rate is practically 100%, influencing graft and patient survivals; within 5 years cirrhosis develops again in 20% to 30% of cases. The therapy is pegylated interferon α-2a and α-2b plus ribavirin as for nontransplanted subjects with the goal to eradicate the virus and maintain graft function. In 25% to 45% of treated patients, it is possible to achieve a sustained virological response (SVR). The response is influenced by viral, donor, and recipient factors. We investigated the genotype of 68 liver recipients transplanted because of hepatitis C virus (HCV) infection between September 1998 and February 2011. We focused on the interleukin (IL) 28B gene locus single nucleotide polymorphism found on chromosome 19; the rs12979860 minor allele (homozygous [wild TT and CC], heterozygous [CT]) in relation to the interferon response. Ten percent of the patients belonged to the CC, 62% to the CT, and 28% to the TT group, and 83% of the CC group became negative or therapy is still ongoing. The CT genotype reached 15.4% SVR with ongoing treatment for most patients. In TT carriers showed a 23.5% SVR. Our patients formed a homogenous group regarding the surgical team, the therapy, and the HCV genotype. Ninety percent belonged to the possible "hard to treat" group. The 10% CC group gave the highest number of SVR and HCV polymerase chain reaction negativity upon antiviral therapy. Regarding our results, one has to take in consideration the small patient number and the fact that the cirrhotic patients were listed for transplantation where they could not be treated or became therapy-resistant. IL28B is just one predictive factor among others for successful posttransplant HCV therapy; further examinations are needed to fully understand its role.

The pharmacokinetics of peginterferon alfa-2a and ribavirin in African American, Hispanic and Caucasian patients with chronic hepatitis C

BACKGROUND

Amongst Caucasian, Hispanic and African Americans with genotype 1 hepatitis C virus (HCV), there is a wide variation in response to treatment with peginterferon alfa-2a (PEG-IFN alfa-2a) and ribavirin.

AIM

To evaluate the pharmacokinetics (PK) of PEG-IFN alfa-2a and ribavirin among these three groups.

METHODS

Forty-seven patients with genotype 1 CHC (17 African Americans, 14 Hispanics and 16 Caucasians) received 8 weeks of PEG-IFN alfa-2a (180 μg/week) and ribavirin (1000 or 1200 mg/day). PEG-IFN alfa-2a serum concentrations and ribavirin plasma concentrations were measured following the first dose and at week 8. Pharmacokinetic parameters (C(max), T(max), AUC, CL/F) were estimated using noncompartmental methods.

RESULTS

There was no difference in the pharmacokinetic parameters for PEG-IFN alfa-2a following single-dose or steady-state administration between African American or Hispanic patients compared with Caucasian patients. Ribavirin pharmacokinetic parameters were similar between Hispanic and Caucasian patients for single-dose and steady-state administration. The single-dose C(max) was 33% lower (P < 0.05) in African American compared with Caucasian patients. Other ribavirin single-dose and steady-state pharmacokinetic parameters were slightly decreased (approximately 20% lower) in African American patients, but were not considered clinically meaningful.

CONCLUSIONS

No differences were observed in PEG-IFN alfa-2a pharmacokinetic parameters between African American or Hispanic patients compared with Caucasian patients. For ribavirin, no differences were observed in pharmacokinetic parameters between Hispanic and Caucasian patients. While a trend towards increased ribavirin clearance and decreased exposure was observed in African American patients vs. Caucasian patients, the differences were small and not considered clinically meaningful (Clinical Trial Number: NP17354).

Long-term management of the liver transplant recipient: pearls for the practicing gastroenterologist

Liver transplantation is becoming more common and patients are surviving longer after transplantation. Special care must be paid to the long-term management of these patients because they are at increased risk for medical problems, malignancies, and adverse effects from immunosuppression. A stable and continuing relationship must be developed between the physician and the patient to optimize the long-term outcomes for these individuals.