Drug-drug interactions with oral anti-HCV agents and idiosyncratic hepatotoxicity in the liver transplant setting

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Management of Tacrolimus-Induced Toxicity With Normal Serum Levels After Liver Transplant

Drug-induced liver injury after liver transplant occurs in 1.7% of patients. Tacrolimus is an effective immunosuppressant that is used to treat acute rejection. Although rare, it can cause toxicity, which is demonstrated by cholestatic liver injury. Here, we present a case of a young male patient who was diagnosed with Wilson disease, had penicillaminechelating therapy, and underwent living related liver transplant. Within 1 month posttransplant, he developed deranged, predominantly cholestatic pattern liver function tests. Laboratory parameters showed total bilirubin of 1.12 mg/ dL, alanine aminotransferase of 553 IU/L, gammaglutamyltransferase of 624 IU/L, and tacrolimus level of 10.2 ng/mL. After thorough evaluation, a liver biopsy was performed. Liver biopsy showed hepatocellular necrosis with centrilobular cholestasis without any evidence of graft rejection. However, with normal level of tacrolimus, the biopsy was suggestive of drug-induced liver injury. Thus, tacrolimus dose was reduced, resulting in improved liver function tests and patient discharge from the hospital. Tacrolimus is an effective immunosuppressant after liver transplant and has the ability to treat early acute rejection. The patient's liver biopsy showed hepatocellular necrosis with centrilobular cholestasis without any evidence of graft rejection. Cholestatic liver injury after tacrolimus usually resolves after dose reduction or by switching to another agent. With demonstrated tacrolimus-induced toxicity in liver transplant recipients, despite normal serum levels, transplant physicians should keep high index of suspicion regarding toxicity in the posttransplant setting.

Incidence, clinical features and risk factors of tacrolimus induced idiosyncratic liver injury in renal transplant recipients: A nested case-control study

Rare data reported tacrolimus-induced liver injury (tac-DILI) in real world. We performed a nested case-control analysis of 1,010 renal transplant recipients. Recipients with tac-DILI were randomly matched at a ratio of 1:4 by the year of admission to the remaining recipients without tac-DILI to explore risk factors. The incidence of tac-DILI was 8.9% (95% CI = 7.2–10.7%). The most common type was cholestatic pattern (6.7%, 95% CI = 5.2–8.3%), followed by hepatocellular (1.6%, 95% CI = 0.8–2.4%) and mixed patterns (0.6%, 95% CI = 0.1–1.1%). 98.9% of recipients with tac-DILI have mild severity. The latency period were 42.0 (range, 21.5–99.8 days), 14.0 (range, 9.0–80.3 days), 16.0 (range, 11.5–24.5 days), and 49.0 days (range, 28.0–105.6 days) for total, hepatocellular, mixed, and cholestatic patterns, respectively. Baseline ALP level (OR = 1.015, 95% CI = 1.006–1.025, p = 0.002), age (OR = 0.971, 95% CI = 0.949–0.994, p = 0.006), and body weight (OR = 0.960, 95% CI = 0.940–0.982, p < 0.001) were independent risk factors. In conclusion, cholestatic pattern represents the most frequent type of tac-DILI. Young age, low body weight and abnormal baseline ALP level were risk factors.

Using an Automated Algorithm to Identify Potential Drug-Induced Liver Injury Cases in a Pharmacovigilance Database

INTRODUCTION

Drug-induced liver injury (DILI) is the most frequent cause of acute liver failure in North America and Europe, but it is often missed because of unstandardized diagnostic methods and criteria. This study aimed to develop and validate an automated algorithm to identify potential DILI cases in routine pharmacovigilance (PV) activities.

METHODS

Post-marketing hepatic adverse events reported for a potentially hepatotoxic drug in a global PV database from 19 March 2017 to 18 June 2018 were assessed manually and with the automated algorithm. The algorithm provided case assessments by applying pre-specified criteria to all case data and narratives simultaneously.

RESULTS

A total of 1456 cases were included for analysis and assessed manually. Sufficient data for algorithm assessment were available for 476 cases (32.7%). Of these cases, manual assessment identified 312 (65.5%) potential DILI cases while algorithm assessment identified 305 (64.1%) potential DILI cases. Comparison of manual and algorithm assessments demonstrated a sensitivity of 97.8% and a specificity of 79.3% for the algorithm. Given the prevalence of potential DILI cases in the population studied, the algorithm was calculated to have positive predictive value 56.3% and negative predictive value 99.2%. The time required for manual review compared to algorithm review suggested that application of the algorithm prior to manual screening would have resulted in a time savings of 42.2%.

CONCLUSION

An automated algorithm to identify potential DILI cases was developed and successfully implemented. The algorithm demonstrated a high sensitivity, a high negative predictive value, along with significant efficiency and utility in a real-time PV database.

COVID-19 in liver transplant recipients

Coronavirus disease 2019 (COVID-19), an infection caused by severe acute respiratory syndrome coronavirus-type 2 (SARS-CoV-2), has emerged as a serious threat to public health. Liver transplant (LT) recipients may be at increased risk of acquisition of SARS-CoV-2 infection and higher morbidity and mortality due to constant contact with health-care services, the use of immunosuppressants and frequent comorbidities. In the first part of this review we discuss (1) the epidemiology and risk factors for SARS-CoV-2 infection in LT recipients; (2) the clinical and laboratory features of COVID-19 in this specific population, highlighting differences in presenting signs and symptoms with respect to general populations and (3) the natural history and prognostic factors in LT recipients hospitalized with COVID-19, with particular focus on the possible role of immunosuppression. Thereafter, we review the potential therapeutic options for COVID-19 treatment and prevention. Specifically, we give an overview of current practice in immunosuppressant regimen changes, showing the potential benefits of this strategy, and explore safety and efficacy issues of currently approved drugs in LT recipients. The last topic is dedicated to the potential benefits and pitfalls of vaccination.

Drug-Induced Liver Injury After Liver Transplantation

Drug-induced liver injury (DILI) is an adverse reaction to many drugs in common use that in a liver transplantation (LT) recipient may cause graft dysfunction and may even lead to graft loss and the need for retransplantation. However, several potential clinical scenarios, such as graft rejection and infection, can confound the diagnosis of suspected DILI in the setting of LT. This makes causal assessment of a new liver injury more uncertain and has traditionally precluded collection of bona fide cases of DILI affecting LT patients in prospective DILI registries and cohorts. Although no studies have yet determined a greater susceptibility of the transplant patient to DILI, these patients nevertheless present certain risk factors that can theoretically increase the risk of DILI. These include the fact that these patients are polymedicated, use drugs that are potentially hepatotoxic, and can have coexisting hepatitis B or C viruses in addition to other factors found in nontransplant patients, such as genetic variants. Therefore, awareness is crucial of any potential hepatotoxic effect of drugs used in the LT recipient and their possible implication in any case of liver dysfunction. In the present article, we review the most common drugs used in LT recipients from a liver safety perspective and address the main pitfalls in attributing causality in this clinical setting. We also affirm the need for further research and collaboration in this somewhat neglected topic in the field of DILI.

Recurrent hepatitis C treatment with direct acting antivirals - a real life study at a Brazilian liver transplant center

Recurrent hepatitis C (HCV) after liver transplantation (LT) is an important cause of morbidity and mortality. Antiviral treatment is recommended to avoid unfavorable outcomes. Direct-acting antivirals (DAA) have transformed HCV treatment, with higher efficacy and fewer side-effects than interferon-based therapies traditionally used. To evaluate DAA treatment outcomes at a Brazilian transplant unit, data of patients who finished HCV treatment at the Liver Transplant Unit of the University of Campinas were analyzed. Treatment consisted of sofosbuvir, daclatasvir, and ribavirin, for 12 or 24 weeks, according to the national guidelines. Fifty-five patients completed antiviral treatment and 54 had HCV-viral load results available. The majority of patients were male (78%), 58 years old on average, 65% had hepatocellular carcinoma (HCC) before LT, and 67% were interferon treatment-experienced. Most patients had HCV genotype 1 (65%), 35% had genotype 3, and started treatment on an average of 38 months after LT (range: 2–228). Fifty-eight percent were treated for 12 weeks and 42% for 24 weeks, using a mean dose of ribavirin of 10.1 mg/kg (4.2–16.1). There were no treatment interruptions due to serious side effects. The sustained virological response rate was 98%. Only one patient relapsed, a genotype 3 cirrhotic treated for 12 weeks. The average follow-up after starting antivirals was 20 months. There were no recurrences of HCC, but there was one rejection episode and one cirrhosis decompensation episode, both 12 weeks after treatment. DAA treatment is safe and effective in the post-LT setting and was not associated to HCC recurrence in the cohort studied.

Possible acute rejection associated with the use of the new anti-hepatitis C virus medications

Hepatitis C virus infection is associated with increased morbidity and mortality. It remains a major challenge for management and treatment, especially in patients with renal transplant. The new direct-acting antiviral agents gave big hopes to both clinicians and patients that they can overcome this challenge without major side effects. Studies recently have supported this claim; however, they are still few, limited, and may give false hopes. In the following case report, we present a case, supported by histological evidence about a possible acute rejection of kidney transplant after treatment with these new medications. This case is limited by the absence of donor-specific antibodies. This report is aimed to increase awareness about the urgent need for further studies.

Serum asunaprevir concentrations showing correlation with the extent of liver fibrosis as a factor inducing liver injuries in patients with genotype-1b hepatitis C virus receiving daclatasvir plus asunaprevir therapy

AIMS

Liver injury can occur during antiviral therapies with direct-acting antivirals (DAAs), potentially necessitating discontinuation of the therapies, with consequent worsening of the sustained viral response (SVR) rates, in patients with hepatitis C virus (HCV). To clarify the mechanisms involved in serum transaminase level elevation, we performed a retrospective evaluation of the serum concentrations of daclatasvir and asunaprevir, both classified as DAAs, in patients receiving treatment with a combination of the two drugs.

METHODS

Subjects were 278 Japanese patients with genotype-1b HCV who received daclatasvir plus asunaprevir therapy for more than 4 weeks. Serum concentrations of both the DAAs were measured at 4 weeks after the initiation of therapy.

RESULT

Liver injuries including serum AST and/or ALT level elevation to 150 U/L or over were found in 34 patients (12.2%). Multivariate logistic regression analysis identified serum asunaprevir concentrations as being significantly associated with developing liver injury, with an odds ratio of 1.046 (95% confidence interval 1.011-1.082, p<0.05). Serum asunaprevir concentrations showed correlation with the extent of liver fibrosis, estimated by peripheral platelets counts and serum albumin levels and baseline and FIB4 index and serum Mac-2 binding protein glycosylation isomer (M2BPGi) levels at 4 weeks of the therapy; the concentrations were significantly higher among patients showing 3.0 or more of M2BPGi levels than among those with the levels less than 3.0; on the other hand, no such correlation/difference was found in serum daclatasvir concentrations.

CONCLUSION

High serum concentrations of serum asunaprevir, which were associated with the extent of liver fibrosis, appear to provoke the occurrence of liver injury in patients with genotype-1b HCV receiving combined daclatasvir plus asunaprevir therapy.

Impact of Sofosbuvir-Based Regimens for the Treatment of Hepatitis C After Liver Transplant on Renal Function: Results of a Canadian National Retrospective Study

OBJECTIVES

We assessed the impact of sofosbuvir-based regimens on renal function in liver transplant recipients with recurrent hepatitis C virus and the role of renal function on the efficacy and safety of these regimens.

MATERIALS AND METHODS

In an expanded pan-Canadian cohort, 180 liver transplant recipients were treated with sofosbuvir-based regimens for hepatitis C virus recurrence from January 2014 to May 2015. Mean age was 58 ± 6.85 years, and 50% had F3/4 fibrosis. Patients were stratified into 4 groups based on baseline estimated glomerular filtration rate (calculated by the Modification of Diet in Renal Disease formula): < 30, 30 to 45, 46 to 60, and > 60 mL/min/173 m2. The primary outcome was posttreatment changes in renal function from baseline. Secondary outcomes included sustained virologic response at 12 weeks posttreatment and anemia-related and serious adverse events.

RESULTS

Posttreatment renal function was improved in most patients (58%). Renal function declined in 22% of patients, which was more marked in those with estimated glomerular filtration rate < 30 mL/min/173 m2, advanced cirrhosis (P = .05), and aggressive hepatitis C virus/fibrosing cholestatic hepatitis (P < .05). High rates (80%-88%) of sustained virologic response at 12 weeks posttreatment were seen across all renal function strata. Cirrhotic patients with glomerular filtration rates < 30 mL/min/173 m2 had sustained virologic response rates at 12 weeks posttreatment comparable to the overall patient group. Rates of anemia-related adverse events and transfusion requirements increased across decreasing estimated glomerular filtration rate groups, with notably more occurrences with ribavirin-based regimens.

CONCLUSIONS

Sofosbuvir-based regimens improved overall renal function in liver transplant recipients, with sustained virologic response, suggesting an association of subclinical hepatitis C virus-related renal disease. Sustained virologic response rates at 12 weeks posttreatment (80%-88%) were comparable regardless of baseline renal function but lower in cirrhosis.

Hepatitis C infection in renal transplantation: pathogenesis, current impact and emerging trends

Prevalence of hepatitis C infection, which is associated with mortality and morbidity, is higher in chronic kidney disease patients on hemodialysis and transplant recipients when compared to non HCV infected patients. In addition to the conventional risk factors, HCV infection maybe an additional risk factor in the development of chronic kidney disease. HCV causes adverse effects leading to the poor long term outcome in renal transplant recipients; hepatitis C infection can cause both hepatic as well as extra hepatic complications. Prior evaluation and management of HCV infection is recommended for better long term outcome as there are chances of higher rejection rates with HCV treatment. However transplantation is not contraindicated in those patients who cannot be treated prior to the transplantation as patient survival is better when compared to dialysis patients. Kidney Disease Outcome Quality Initiative Clinical Practice Guidelines recommend interferon based therapy only when there is a rapid worsening of HCV related hepatic injury in transplant recipients. HCV treatment has been improved by the addition of direct acting antiviral, protease inhibitors and polymerase inhibitors. Combination therapies are showing improved sustained virological response rates. NS3-4A protease inhibitors, nucleotidic/nucleosidic NS5A and NS5B polymerase inhibitors are promising treatments which are under trials with different combinations. The focus of this review is to evaluate and optimize the treatment options of co-existing HCV infection in renal transplant recipients and discuss more promising alternative treatment regimen.

Direct Acting Anti-hepatitis C Virus Drugs: Clinical Pharmacology and Future Direction

Chronic hepatitis C virus (HCV) infection is a leading cause of chronic liver disease. The introduction of direct acting antiviral agents (DAAs) for its treatment represents a major advance in terms of sustained virologic response (SVR) rates and adverse effect profiles. Mechanistically, DAAs inhibit specific HCV non-structural proteins (NS) that are vital for its replication. Boceprevir, telaprevir, simeprevir, asunaprevir, grazoprevir and paritaprevir are NS3/4A inhibitors. Ombitasvir, ledipasvir, daclatasvir, elbasvir and velpatasvir are NS5A inhibitors. Sofosbuvir and dasabuvir are NS5B inhibitors. Currently, a combination of two or more DAAs is the corner stone for the treatment of HCV infection. However, the success of DAA therapy is facing several challenges, including the potential of drug-drug interactions and resistant variance. Moreover, the shortage of relevant clinical pharmacological data and drug interaction regarding DAA is a clinical concern. The present review discusses the clinical pharmacology of DAAs with special emphasis on drug-drug interaction.

Safety of direct antiviral agents for treatment of hepatitis C virus infection

Antiviral drugs for treatment of hepatitis C have grown dramatically in recent years. The emergence of direct antiviral agents (DAAs) is a major advance in hepatitis C treatment. Since the first generation DAAs appeared in 2011, two more generations of DAAs have been approved by the Food and Drug Administration in only five years. With the advantages of coverage of all genotypes, high availability and easy administration, DAAs have been widely used worldwide in recent years. DAAs have nearly solved the main problems encountered in hepatitis C antiviral therapy. However, adverse events associated with DAAs use have been reported constantly, and the safety of DAAs has attracted more and more attention. According to recent reports, the adverse reactions of DAAs have been gradually reduced from the first generation to the third generation. When combined with other drugs, the drug-drug interactions (DDIs) need special attention. In addition, the usage of DAAs in special patient groups should be cautious. In this paper, we will summarize the adverse effects and DDIs of DAAs as well as their usage in the general population and special patient groups.

Drug Metabolism in the Liver

Metabolism is a biotransformation process, where endogenous and exogenous compounds are converted to more polar products to facilitate their elimination from the body. The process of metabolism is divided into 3 phases. Phase I metabolism involves functionalization reactions. Phase II drug metabolism is a conjugation reaction. Phase III refers to transporter-mediated elimination of drug and/or metabolites from body normally via liver, gut, kidney, or lung. This review presents basic information on drug-metabolizing enzymes and potential factors that might affect the metabolic capacities of the enzyme or alter drug response or drug-mediated toxicities.

Drug Metabolism, Drug Interactions, and Drug-Induced Liver Injury in Living Donor Liver Transplant Patients

Living donor liver transplant (LDLT) fills a critically needed gap in the number of livers available for transplant. However, little is known about the functional recovery of the liver in the donor and in the recipient after surgery. Given that both donor and recipients are treated with several drugs, it is important to characterize the time course of recovery of hepatic synthetic, metabolic, and excretory function in these patients. In the absence of data from LDLT, information on the effect of liver disease on the pharmacokinetics of medications can be used as guidance for drug dosing in LDLT patients.

Drug metabolism and liver disease: a drug-gene-environment interaction

Despite the central role of the liver in drug metabolism, surprisingly there is lack of certainty in anticipating the extent of modification of the clearance of a given drug in a given patient. The intent of this review is to provide a conceptual framework in considering the impact of liver disease on drug disposition and reciprocally the impact of drug disposition on liver disease. It is proposed that improved understanding of the situation is gained by considering the issue as a special example of a drug-gene-environment interaction. This requires an integration of knowledge of the drug's properties, knowledge of the gene products involved in its metabolism, and knowledge of the pathophysiology of its disposition. This will enhance the level of predictability of drug disposition and toxicity for a drug of interest in an individual patient. It is our contention that advances in pharmacology, pharmacogenomics, and hepatology, together with concerted interests in the academic, regulatory, and pharmaceutical industry communities provide an ideal immediate environment to move from a qualitative reactive approach to quantitative proactive approach in individualizing patient therapy in liver disease.

Drug-Drug Interactions with the NS3/4A Protease Inhibitor Simeprevir

Simeprevir is an NS3/4A protease inhibitor approved for the treatment of hepatitis C infection, as a component of combination therapy. Simeprevir is metabolized by the cytochrome P450 (CYP) system, primarily CYP3A, and is a substrate for several drug transporters, including the organic anion transporting polypeptides (OATPs). It is susceptible to metabolic drug–drug interactions with drugs that are moderate or strong CYP3A inhibitors (e.g. ritonavir and erythromycin) or CYP3A inducers (e.g. rifampin and efavirenz); coadministration of these drugs may increase or decrease plasma concentrations of simeprevir, respectively, and should be avoided. Clinical studies have shown that simeprevir is a mild inhibitor of CYP1A2 and intestinal CYP3A but does not inhibit hepatic CYP3A. The effects of simeprevir on these enzymes are of clinical relevance only for narrow-therapeutic-index drugs that are metabolized solely by these enzymes (e.g. oral midazolam). Simeprevir does not have a clinically relevant effect on the pharmacokinetics of rilpivirine, tacrolimus, oral contraceptives and several other drugs metabolized by CYP enzymes. Simeprevir is a substrate and inhibitor of the transporters P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and OATP1B1/3. Cyclosporine is an inhibitor of OATP1B1/3, BCRP and P-gp, and a mild inhibitor of CYP3A; cyclosporine causes a significant increase in simeprevir plasma concentrations, and coadministration is not recommended. Clinical studies have demonstrated increases in coadministered drug concentrations for drugs that are substrates of the OATP1B1/3, BRCP (e.g. rosuvastatin) and P-gp (e.g. digoxin) transporters; these drugs should be administered with dose titration and or/close monitoring.

Multicentre experience using daclatasvir and sofosbuvir to treat hepatitis C recurrence - The ANRS CUPILT study

BACKGROUND & AIMS

HCV recurrence remains a major issue in the liver transplant field, as it has a negative impact on both graft and patient survival. The purpose of this study was to investigate the efficacy and safety of treating HCV recurrence with sofosbuvir (SOF) and daclatasvir (DCV) combination therapy.

METHODS

From October 2013 to March 2015, 559 liver recipients were enrolled in the prospective multicentre France REcherche Nord&Sud Sida-hiv Hépatites (ANRS) Compassionate use of Protease Inhibitors in viral C Liver Transplantation cohort. We selected 137 patients with an HCV recurrence receiving SOF and DCV, whatever the genotype or fibrosis stage. The use of ribavirin and the duration of therapy were at the investigator's discretion. The primary efficacy end point was a sustained virological response (SVR) 12weeks after the end of treatment.

RESULTS

The SVR rate 12weeks after completing treatment was 96% under the intention-to treat analysis and 99% when excluding non-virological failures. Only two patients experienced a virological failure. The serious adverse event (SAE) rate reached 17.5%. Four patients (3%) stopped their treatment prematurely because of SAEs. Anaemia was the most common AE, with significantly more cases in the ribavirin group (56% vs. 18%; p<0.0001). A slight but significant reduction in creatinine clearance was reported. No clinically relevant drug-drug interactions were noted, but 52% of patients required a change to the dosage of immunosuppressive drugs.

CONCLUSIONS

Treatment with SOF plus DCV was associated with a high SVR12 and low rates of serious adverse events among liver recipients with HCV recurrence.

LAY SUMMARY

The recurrence of hepatitis C used to be the first cause of graft failure in infected liver transplanted recipients. Our study demonstrates the great efficacy of one combination of new all-oral direct-acting antiviral, sofosbuvir and daclatasvir, to treat the recurrence of hepatitis C on the graft. Ninety-six per cent of recipients were cured. The safety profile of this combination seemed to be good, especially no relevant drug-drug interaction with immunosuppressive drugs.

Daclatasvir-based Treatment Regimens for Hepatitis C Virus Infection: A Systematic Review and Meta-Analysis

CONTEXT

Direct acting antivirals (DAAs) have recently emerged as a promising therapeutic regimen for the treatment of hepatitis C virus (HCV) infection, which is a major public health problem. Among the known DAAs, daclatasvir (DCV), an inhibitor of the non-structural 5A protein, has been used in combination with several drugs for treatment of infection with HCV of different genotypes under different conditions. We conducted a systematic review and meta-analysis of combination therapy with DCV.

EVIDENCE ACQUISITION

We performed a systematic search in PubMed, Scopus, Science Direct and Web of Science with appropriate keywords for DCV. Studies that evaluated any regimen containing DCV and reported the sustained virological response (SVR) 12 weeks after therapy based on the HCV genotype, treatment duration and use of ribavirin (RBV) were included. The selected studies were considered for meta-analysis using STATA 11.0.

RESULTS

We found six different regimens containing DCV: DCV/asunaprevir (ASV), DCV/ASV/beclubavir, DCV/pegylated interferon lambda or alpha/RBV with or without ASV, DCV/simeprevir, DCV/VX-135 and DCV/sofosbuvir (SOF). Most of these regimens were used for the treatment of HCV genotype 1 infections, and in most cases, treatment failure was noted in subtype 1a infections. Among all these regimens, DCV/SOF with or without RBV for 12 or 24 weeks was found to be an efficacious approach for treatment of different types of patients with infections with different HCV genotypes.

CONCLUSIONS

Among the treatment regimens containing DCV, DCV/SOF has the highest SVR rate for the treatment of infection with different HCV genotypes in different patient contexts; thus, this regimen shows promise for the treatment of HCV infections.

Management of post liver transplantation recurrent hepatitis C infection with directly acting antiviral drugs: a review

Recurrent HCV infection (rHCV) of the liver allograft following transplantation is universal and is associated with poor graft and patient survival in comparison with other indications. Treatment of rHCV infection in the previous era with pegylated interferon and ribavirin was associated with low sustained virological response (SVR) due to poor tolerability, adverse events and graft rejection. Recently, directly acting antiviral drugs (DAA) have been approved for the treatment of hepatitis C infection and a number of clinical trials have been conducted across various centers in the management of rHCV infection of the graft. In this review we discuss about recent studies that have emerged on the use of NS5b polymerase inhibitor, sofosbuvir in combination with second generation protease inhibitor, simeprevir, fixed dose ledipasvir or daclatasvir with or without ribavirin in the treatment of post transplant rHCV infection.

Daclatasvir with sofosbuvir and ribavirin for hepatitis C virus infection with advanced cirrhosis or post-liver transplantation recurrence

Chronic hepatitis C virus (HCV) infection with advanced cirrhosis or post-liver transplantation recurrence represents a high unmet medical need with no approved therapies effective across all HCV genotypes. The open-label ALLY-1 study assessed the safety and efficacy of a 60-mg once-daily dosage of daclatasvir (pan-genotypic NS5A inhibitor) in combination with sofosbuvir at 400 mg once daily (NS5B inhibitor) and ribavirin at 600 mg/day for 12 weeks with a 24-week follow-up in two cohorts of patients with chronic HCV infection of any genotype and either compensated/decompensated cirrhosis or posttransplantation recurrence. Patients with on-treatment transplantation were eligible to receive 12 additional weeks of treatment immediately after transplantation. The primary efficacy measure was sustained virologic response at posttreatment week 12 (SVR12) in patients with a genotype 1 infection in each cohort. Sixty patients with advanced cirrhosis and 53 with posttransplantation recurrence were enrolled; HCV genotypes 1 (76%), 2, 3, 4, and 6 were represented. Child-Pugh classifications in the advanced cirrhosis cohort were 20% A, 53% B, and 27% C. In patients with cirrhosis, 82% (95% confidence interval [CI], 67.9%-92.0%) with genotype 1 infection achieved SVR12, whereas the corresponding rates in those with genotypes 2, 3, and 4 were 80%, 83%, and 100%, respectively; SVR12 rates were higher in patients with Child-Pugh class A or B, 93%, versus class C, 56%. In transplant recipients, SVR12 was achieved by 95% (95% CI, 83.5%-99.4%) and 91% of patients with genotype 1 and 3 infection, respectively. Three patients received peritransplantation treatment with minimal dose interruption and achieved SVR12. There were no treatment-related serious adverse events.

CONCLUSION

The pan-genotypic combination of daclatasvir, sofosbuvir, and ribavirin was safe and well tolerated. High SVR rates across multiple HCV genotypes were achieved by patients with post-liver transplantation recurrence or advanced cirrhosis.

Interferon-Free Therapy for Hepatitis C in Liver Transplant Recipients

Recurrence of hepatitis C after liver transplantation is a major problem; it is characterized by high hepatitis C virus (HCV)-RNA, rapid progression, and cholestatic hepatitis. Treatment for HCV infection with peginterferon and ribavirin has been administered to prevent progression of hepatitis C after liver transplantation. However, it has low efficacy and causes many adverse events, including immune-mediated graft dysfunction. Interferon-containing regimens with direct-acting antivirals (DAAs) improve treatment efficacy but DAAs cause serious adverse events and drug-drug interactions. Recent studies have demonstrated the efficacy and safety of interferon-free therapy with DAAs before and after liver transplantation, which has ushered in a new era in the strategy for treating HCV in transplant recipients. Interferon-free therapies are safe and effective in patients before and after liver transplantation as well as in those with severe cholestatic hepatitis C. Several obstacles must be overcome before the widespread adoption of interferon-free therapy, including drug-drug interactions, DAA-resistant HCV, treatment for decompensated cirrhosis, and treatment for renal failure. These problems are expected to be solved in the near future, and the poor prognosis of HCV-positive recipients will improve.

Sofosbuvir-Based Therapy for Genotype 4 HCV Recurrence Post-Liver Transplant Treatment-Experienced Patients

Background and Aim. This is an open label prospective cohort study conducted at a tertiary care hospital. The primary endpoint is SVR12 in patients treated with sofosbuvir-based therapy in post-liver transplant patients with genotype 4 HCV recurrence. Methodology. Thirty-six treatment-experienced liver transplant patients with HCV recurrence received sofosbuvir and ribavirin ± peginterferon. Results. We report here safety and efficacy data on 36 patients who completed the follow-up period. Mean age was 56 years, and the cohort included 24 males and one patient had cirrhosis. Mean baseline HCV RNA was 6.2 log10 IU/mL. The majority of patients had ≥ stage 2 fibrosis. Twenty-eight patients were treated with pegylated interferon plus ribavirin in addition to sofosbuvir for 12 weeks and the remaining were treated with sofosbuvir plus ribavirin only for 24 weeks. By week 4, only four (11.1%) patients had detectable HCV RNA. Of the 36 patients, 2 (5.5%) relapsed and one died (2.75%). Conclusion. Our results suggest that sofosbuvir + ribavirin ± pegylated interferon can be utilized successfully to treat liver transplant patients with HCV recurrence.

Cost-effectiveness of Ombitasvir/Paritaprevir/Ritonavir, Dasabuvir+Ribavirin for US Post-Liver Transplant Recurrent Genotype 1 HCV

BACKGROUND & AIMS

Orthotopic liver transplant patients with recurrent hepatitis C (HCV) historically have had limited treatment options. Ombitasvir/paritaprevir/ritonavir, dasabuvir and ribavirin (3D+R) was approved by the FDA in December 2014 for liver transplant recipients with recurrent genotype 1 HCV, in whom it is effective and well-tolerated.

METHODS

Using a two-phase Markov model, we analysed the cost-effectiveness of 3D+R in liver transplant recipients, the only HCV treatment with FDA approval in this population. As a sensitivity analysis, we also considered the cost-effectiveness of pegylated interferon plus ribavirin, the only other therapy with data from Phase III trials in this population. Patients were given one of three options: 3D+R for 24 weeks, pegylated interferon and ribavirin for 48 weeks (PR48) or no treatment (NT). Patients were then followed through subsequent disease progression until death. Outcome measures analysed were: lifetime risks of liver morbidity and mortality, treatment costs, non-treatment medical expenditures, and quality-adjusted life years.

RESULTS

Treatment with 3D+R was associated with a significantly lower lifetime risk of liver-related morbidity and mortality than treatment with PR48 or NT. 3D+R also was associated with a higher gain in quality-adjusted life years (11.3 compared to 8.25 with NT) and lower discounted overall costs ($423,585 compared to $724,757 with NT).

CONCLUSIONS

The use of 3D+R for liver transplant recipients with recurrent HCV is an outcome-improving and cost-effective regimen for this population with limited treatment options and large unmet need.

Hepatic decompensation/serious adverse events in post-liver transplantation recipients on sofosbuvir for recurrent hepatitis C virus

AIM: To determine the safety profile of new hepatitis C virus (HCV) treatments in liver transplant (LT) recipients with recurrent HCV infection.

METHODS: Forty-two patients were identified with recurrent HCV infection that underwent LT at least 12 mo prior to initiating treatment with a Sofosbuvir-based regimen during December 2013-June 2014. Cases were patients who experienced hepatic decompensation and/or serious adverse events (SAE) during or within one month of completing treatment. Controls had no evidence of hepatic decompensation and/or SAE. HIV-infected patients were excluded. Cumulative incidence of decompensation/SAE was calculated using the Kaplan Meier method. Exact logistic regression analysis was used to identify factors associated with the composite outcome.

RESULTS: Median age of the 42 patients was 60 years [Interquartile Range (IQR): 56-65 years], 33% (14/42) were female, 21% (9/42) were Hispanic, and 9% (4/42) were Black. The median time from transplant to treatment initiation was 5.4 years (IQR: 2.1-8.8 years). Thirteen patients experienced one or more episodes of hepatic decompensation and/or SAE. Anemia requiring transfusion, the most common event, occurred in 62% (8/13) patients, while 54% (7/13) decompensated. The cumulative incidence of hepatic decompensation/SAE was 31% (95%CI: 16%-41%). Risk factors for decompensation/SAE included lower pre-treatment hemoglobin (OR = 0.61 per g/dL, 95%CI: 0.40-0.88, P < 0.01), estimated glomerular filtration rate (OR = 0.95 per mL/min per 1.73 m², 95%CI: 0.90-0.99, P = 0.01), and higher baseline serum total bilirubin (OR = 2.43 per mg/dL, 95%CI: 1.17-8.65, P < 0.01). The sustained virological response rate for the cohort of 42 patients was 45%, while it was 31% for cases.

CONCLUSION: Sofosbuvir/ribavirin will continue to be used in the post-transplant population, including those with HCV genotypes 2 and 3. Management of anemia remains an important clinical challenge.

Treatment of Chronic Hepatitis C in Special Populations

The management of hepatitis C virus (HCV) infection in special populations is challenging. The efficacy and safety data of the currently approved all-oral direct-acting antiviral combinations, including sofosbuvir, ledipasvir, daclatasvir, paritaprevir/ritonavir/ombitasvir plus dasabuvir (3D), and ribavirin, is compelling for use in special HCV populations, as has recently been recommended by expert guidelines. The treatment regimens and sustained virological response rates for special populations are nearly similar to those of the general HCV population. Sofosbuvir is not recommended in patients with severe renal impairment, and simeprevir and 3D regimen are not recommended for those with decompensated liver disease.

Cutaneous manifestations of hepatitis C in the era of new antiviral agents

The association of chronic hepatitis C virus (HCV) infection with a wide spectrum of cutaneous manifestations has been widely reported in the literature, with varying strength of epidemiological association. Skin diseases which are certainly related with chronic HCV infection due to a strong epidemiological and pathogenetic association are mixed cryoglobulinemia, lichen planus and porphyria cutanea tarda. Chronic pruritus and necrolytic acral erythema are conditions that may share a possible association with HCV infection, while several immune-mediated inflammatory skin conditions, such as psoriasis, chronic urticaria and vitiligo, have been only anecdotally reported in the setting of chronic HCV infection. Traditional interferon-based treatment regimens for HCV infection are associated with substantial toxicity and a high-risk of immune-related adverse events, while the advent of new direct-acting antivirals with sustained virological response and improved tolerability will open the door for all-oral, interferon-free regimens. In the new era of these direct acting antivirals there will be hopefully a renewed interest in extra-hepatic manifestations of HCV infection. The aim of the present paper is to review the main cutaneous HCV-related disorders - mixed cryoglobulinemia, lichen planus, porphyria cutanea tarda and chronic pruritus - and to discuss the potential impact of new antiviral treatments on the course of these extra-hepatic manifestations of chronic HCV infection.

New hepatitis C therapies for special patient populations

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. More than 90% sustained virologic response rates have been obtained with 8-24 weeks of treatment with distinct combinations of direct-acting antivirals (DAA) in most registration trials. However, outcomes in real-world patients tend to be lower and treatment of special patient populations is often challenging.

AREAS COVERED

We address the treatment of chronic hepatitis C with DAA in major special patient populations, such as HIV-positive persons, transplant recipients, patients with advanced cirrhosis, renal insufficiency, hepatitis B or D coinfection, injection drug users (IDUs) and prior DAA failures.

EXPERT OPINION

Drug interactions between DAA and medications given to persons with HIV infection or transplant recipients can result in treatment failure and adverse events. Severe organ dysfunction as in kidney insufficiency or decompensated cirrhosis may lead to DAA overexposure and toxicities. Dysfunctional social circumstances and behavior are associated to poor drug adherence and increased risk for HCV re-infection in active IDUs. Finally, DAA response might be impaired by viral interference in patients with hepatitis B or D coinfection or drug resistance in HCV either at baseline or after prior DAA failures.

Daclatasvir-containing all-oral regimens for the treatment of hepatitis C virus infection

The treatment of chronic hepatitis C is revolutionizing rapidly. The aim of this study is to review the efficacy and safety of daclatasvir (DCV)-containing all-oral regimens in clinical studies for chronic hepatitis C treatment. Using PubMed and search terms of 'DCV,' 'hepatitis C virus (HCV) treatment,' and 'HCV NS5A inhibitors,' literature on the clinical development of DCV, as well as abstracts presented at the April 2015 annual meeting of the European Association for the Study of the Liver (EASL) and November 2014 annual meeting of the American Association for the Study of Liver Diseases were reviewed. The final search was undertaken on 14 July 2015. With its potent antiviral activity to all HCV genotypes (GT) demonstrated in preclinical, phases 1-3 studies, DCV has been acting as a very competent team player in clinical trials of all-oral regimens. It is generally safe and well tolerated with a low genetic barrier to resistance and low potential for drug-drug interaction. Administered with a non-structural protein 3 (NS3) protease inhibitor (asunaprevir, ASV) with or without a non-nucleoside NS5B polymerase inhibitor (beclabuvir, BCV), or a nucleotide NS5B polymerase inhibitor (sofosbuvir, SOF), DCV is able to achieve greater than a 90-% HCV eradication rate in both treatment-naïve and treatment-experienced patients with GT 1. A triple combination regimen with DCV/ASV/BCV results in 100% sustained virologic response (SVR) rates in HCV GT 4 treatment-naïve subjects. DCV/SOF combination also had demonstrated up to 90-% SVR rates in GT 3-infected non-cirrhotic patients. The efficacy and safety of DCV-containing all-oral regimens highlight a new era of interferon-free therapy for chronic hepatitis C.

Current Management of Hepatitis C Virus: Regimens for Peri-Liver Transplant Patients

Chronic hepatitis C virus (HCV) infection currently remains the leading indication for liver transplant in the United States. However, recurrent HCV infection after transplant is universal in those who enter transplant with viremia resulting in reduced posttransplant graft and patient survival rates, caused in large part by progressive recurrent HCV disease. Therefore, successful treatment of HCV in the peri-transplant period, either before or after transplant, is paramount in ensuring improved posttransplant outcomes. This article reviews the experience to date treating HCV in wait-listed patients and liver transplant recipients and the unique challenges encountered when treating this population.

Sofosbuvir plus simeprevir treatment of recurrent genotype 1 hepatitis C after liver transplant

BACKGROUND

Patients with recurrent hepatitis C (HCV) infection post-liver transplant can be difficult to treat safely and effectively. A prior (COSMOS) study in patients with non-transplant HCV, using sofosbuvir plus simeprevir, had high efficacy and tolerability in treating patients with HCV genotype 1, even prior non-responders to interferon therapy and those with cirrhosis. Our aim was to evaluate the efficacy of sofosbuvir and simeprevir in patients with genotype 1 HCV post-liver transplant.

METHODS

In this prospective, observational study, patients received sofosbuvir 400 mg plus simeprevir 150 mg daily for 12 wk without ribavirin. The primary end point was a sustained virologic response 12 wk after the end of therapy.

RESULTS

Forty-two patients completed the treatment. Twenty-six percent started the treatment ≤ 6 months post-liver transplant. Nineteen percent of the included patients had cirrhosis, 14% with decompensation. At week 4 on the treatment, 21% of patients had detectable virus but at the end of the treatment, 100% were undetectable. Twelve weeks after the end of the treatment, 95% of the patients had undetectable hepatitis C. The regimen was generally well tolerated.

CONCLUSION

The oral regimen of sofosbuvir plus simeprevir without ribavirin is efficacious and well tolerated in the treatment of patients with genotype 1 hepatitis C post-liver transplant.

Hepatitis C in Special Patient Cohorts: New Opportunities in Decompensated Liver Cirrhosis, End-Stage Renal Disease and Transplant Medicine

Worldwide, hepatitis C virus (HCV) is a common infection. Due to new antiviral approaches and the approval of direct-acting antiviral agents (DAA), HCV therapy has become more comfortable. Nevertheless, there are special patient groups, in whom treatment of HCV is still challenging. Due to only few data available, tolerability and efficacy of DAAs in special patient cohorts still remain unclear. Such special patient cohorts comprise HCV in patients with decompensated liver disease (Child-Pugh Class B or C), patients with chronic kidney disease, and patients on waiting lists to renal/liver transplantation or those with HCV recurrence after liver transplantation. HCV infection in these patient cohorts has been shown to be associated with increased morbidity and mortality and may lead to reduced graft survival after transplantation. Successful eradication of HCV results in a better outcome concerning liver-related complications and in a better clinical outcome of these patients. In this review, we analyze available data and results from recently published literature and provide an overview of current recommendations of HCV-therapy regimen in these special patient cohorts.

Review article: the efficacy and safety of daclatasvir in the treatment of chronic hepatitis C virus infection

BACKGROUND

The treatment of hepatitis C virus (HCV) has evolved dramatically after the introduction of direct acting anti-virals. NS5A protein plays an important role in HCV replication and is an attractive target for drug development.

AIM

To review clinical studies on the efficacy and safety of direct-acting anti-virals regimens containing daclastavir, an NS5A inhibitor, in the treatment of chronic hepatitis C.

METHODS

A Medline search was undertaken to identify relevant literature using search terms including 'daclatasvir', 'HCV treatment' and 'NS5A inhibitors'. Furthermore, we scanned abstracts presented at the recent international meetings in liver disease, viral hepatitis and infectious disease, as well as the reference lists of the review articles to identify publications not retrieved by electronic searches.

RESULTS

Daclatasvir is the first-in-class HCV NS5A inhibitor that has been demonstrated in Phase I-III trials to have a potent anti-viral effect and clinical efficacy across multiple HCV genotypes (GT). Daclastavir is generally safe and well tolerated, with a low barrier to resistance and low potential for drug-drug interaction. When Daclastavir is added to PEG-IFN/RBV platform, sustained virological response (SVR) rates are increased significantly compared with PEG-IFN/RBV alone. The all-oral combination of Daclastavir/asunaprevir (ASV; protease inhibitor) has high SVR rates against GT1b, but less activity against GT1a. Dual combination of Daclastavir/Sofosbuvir (SOF; nucleotide polymerase inhibitor) and triple combination of Daclastavir/ASV/beclabuvir (BCV; non-nucleoside polymerase inhibitor) have demonstrated >90% SVR rates in both treatment naïve and treatment-experienced patients with GT1. Furthermore, Daclastavir/SOF combination has also demonstrated up to 90% SVR rates in patients with GT3, and in those with human immunodeficiency virus coinfection, cirrhosis and post-transplant HCV recurrence with any GT. Daclastavir/ASV/BCV has primarily demonstrated near 100% SVR rates in patients with GT4.

CONCLUSION

Daclastavir-containing regimens, with or without PEG-IFN, have shown promising results in clinical trials, and present an excellent treatment option for those with chronic HCV and for multiple genotypes.

Utility of the low-accelerating-dose regimen in 182 liver recipients with recurrent hepatitis C virus

AIM

To describe our experience using a low-accelerating-dose regimen (LADR) with pegylated interferon alpha-2a and ribavirin in treatment of hepatitis C virus (HCV) recurrence.

METHODS

From 2003, a protocolized LADR strategy was employed to treat liver transplant (LT) recipients with recurrent HCV at our institution. Medical records of 182 adult patients with recurrent HCV treated with LADR between 1/2003 and 1/2011 were reviewed. Histopathology from all post-LT liver biopsies were reviewed in a blinded fashion. Paired recipient and donor IL28B status were assessed. A novel technique was employed to ascertain recipient and donor IL28B (rs12979860) Gt data using DNA extracted from archival FFPE tissue from explanted native livers and donor gallbladders respectively. The primary endpoint was SVR; secondary endpoints examined include (1) patient and graft survival; (2) effect of anti-viral therapy on liver histology (fibrosis and inflammation); (3) incidence of on-treatment development of ACR, CDR, or PCH; (4) association of recipient and donor IL28B genotype with SVR; and (5) incidence of anti-viral therapy-associated adverse events (anemia, leukopenia, thrombocytopenia, depression) and hepatic decompensation.

RESULTS

The overall SVR rate was 38% (29% Gt1, 67% Gt2, 86% Gt3 and 58% Gt4). HCV Gt (P < 0.0001), donor age (P = 0.003), cytomegalovirus mismatch (P = 0.001), baseline serum bilirubin (P = 0.002), and baseline viral load (P = 0.04) were independent predictors for SVR. SVR rates were significantly higher in the recipient-CC/donor-non CC pairs (P = 0.007). Neither baseline fibrosis nor change in fibrosis stage after anti-viral therapy were associated with SVR. Fibrosis progressed in 72% of patients despite SVR. Median graft survival was 91 mo. Five-year patient survival was superior in patients who achieved SVR (97% vs 82%, P = 0.001). Pre-treatment ALP ≥ 150 U/L (P = 0.01), total bilirubin ≥ 1.5 mg/dL (P = 0.001) and creatinine ≥ 2 mg/dL (P = 0.001) were independently associated with patient survival. Only 13% of patients achieving SVR died during the follow-up period. Treatment discontinuation and treatment-related mortality occurred in 35% and 2.2% of patients, respectively. EPO, G-CSF and blood transfusion were needed in 89%, 40% and 23% of patients, respectively. Overall hospitalization rate for treatment-related serious adverse events was 21%. Forty-six (25%) of the patients were deceased; among those who died, 25 (54%) were due to liver-related complications, and 4 deaths (9%) occurred while receiving therapy (2 patients experienced hepatic decompensation and 2 sepsis).

CONCLUSION

LADR strategy remains relevant in managing post-LT recurrent HCV where access to DAAs is limited. SVR is associated with improved survival, but fibrosis progression still occurs.

Hepatitis C virus recurrence after liver transplantation: A 10-year evaluation

AIM: To evaluate the predictors of 10-year survival of patients with hepatitis C recurrence.

METHODS: Data from 358 patients transplanted between 1989 and 2010 in two Italian transplant centers and with evidence of hepatitis C recurrence were analyzed. A χ², Fisher’s exact test and Kruskal Wallis’ test were used for categorical and continuous variables, respectively. Survival analysis was performed at 10 years after transplant using the Kaplan-Meier method, and a log-rank test was used to compare groups. A P level less than 0.05 was considered significant for all tests. Multivariate analysis of the predictive role of different variables on 10-year survival was performed by a stepwise Cox logistic regression.

RESULTS: The ten-year survival of the entire population was 61.2%. Five groups of patients were identified according to the virological response or lack of a response to antiviral treatment and, among those who were not treated, according to the clinical status (mild hepatitis C recurrence, “too sick to be treated” and patients with comorbidities contraindicating the treatment). While the 10-year survival of treated and untreated patients was not different (59.1% vs 64.7%, P = 0.192), patients with a sustained virological response had a higher 10-year survival rate than both the “non-responders” (84.7% vs 39.8%, P < 0.0001) and too sick to be treated (84.7% vs 0%, P < 0.0001). Sustained virological responders had a survival rate comparable to patients untreated with mild recurrence (84.7% vs 89.3%). A sustained virological response and young donor age were independent predictors of 10-year survival.

CONCLUSION: Sustained virological response significantly increased long-term survival. Awaiting the interferon-free regimen global availability, antiviral treatment might be questionable in selected subjects with mild hepatitis C recurrence.

Hepatic decompensation likely attributable to simeprevir in patients with advanced cirrhosis

BACKGROUND

Hyperbilirubinemia is a common side effect of protease inhibitors used to treat chronic hepatitis C (HCV), and most patients do not experience without clinically overt hepatotoxicity. The safety of second-wave protease inhibitors, including simeprevir, has not been well studied in patients with advanced cirrhosis.

MATERIALS & METHODS

We report two cases of suspected drug-induced liver injury leading to hepatic decompensation in patients with advanced HCV cirrhosis treated with the combination of simeprevir and sofosbuvir on a compassionate basis. Both patients developed marked hyperbilirubinemia out of proportion to their aminotransferases, despite clearance of hepatitis C RNA. RUCAM scoring was probable and possible, respectively. While other factors may have contributed to the liver injury, including infection and concurrent administration of other medications, we believe that the potentially deleterious hepatic effects of simeprevir on transporters or other key functional components were the main reason for their decompensation.

CONCLUSIONS

Protease inhibitors should be used with caution, if at all, in patients with cirrhosis, especially in those with the most advanced disease. We await newer, safer, direct-acting antiviral therapies for such patients, especially those on our transplant list.

Effective epitope identification employing phylogenetic, mutational variability, sequence entropy, and correlated mutation analysis targeting NS5B protein of hepatitis C virus: from bioinformatics to therapeutics

Hepatitis C virus (HCV) is considered as a foremost cause affecting numerous human liver-related disorders. An effective immuno-prophylactic measure (like stable vaccine) is still unavailable for HCV. We perform an in silico analysis of nonstructural protein 5B (NS5B) based CD4 and CD8 epitopes that might be implicated in improvement of treatment strategies for efficient vaccine development programs against HCV. Here, we report on effective utilization of knowledge obtained from multiple sequence alignment and phylogenetic analysis for investigation and evaluation of candidate epitopes that have enormous potential to be used in formulating proficient vaccine, embracing multiple strains prevalent among major geographical locations. Mutational variability data discussed herein focus on discriminating the region under active evolutionary pressure from those having lower mutational potential in existing experimentally verified epitopes, thus, providing a concrete framework for designing an effective peptide-based vaccine against HCV. Additionally, we measured entropy distribution in NS5B residues and pinpoint the positions in epitopes that are more susceptible to mutations and, thus, account for virus strategy to evade the host immune system. Findings from this study are expected to add more details on the sequence and structural aspects of NS5B protein, ultimately facilitating our understanding about the pathophysiology of HCV and assisting advance studies on the function of NS5B antigen on the epitope level. We also report on the mutational crosstalk between functionally important coevolving residues, using correlated mutation analysis, and identify networks of coupled mutations that represent pathways of allosteric communication inside and among NS5B thumb, finger, and palm domains.

Management of patients with hepatitis C infection and renal disease

Hepatitis C virus (HCV) infection in patients with end-stage renal disease (ESRD) is associated with more rapid liver disease progression and reduced renal graft and patients' survival following kidney transplantation. Evaluations and management of HCV in patients with renal disease are challenging. The pharmacokinetics of interferons (IFN), ribavirin (RBV) and some direct acting antiviral (DAA), such as sofosbuvir, are altered in patients with ESRD. With dose adjustment and careful monitoring, treatment of HCV in patients with ESRD can be associated with sustained virological response (SVR) rates nearly comparable to that of patients with normal renal function. DAA-based regimens, especially the IFN-free and RBV-free regimens, are theoretically preferred for patients with ESRD and KT in order to increase SVR rates and to reduce treatment side effects. However, based on the data for pharmacokinetics, dosing safety and efficacy of DAA for patients with severe renal impairment are lacking. This review will be focused on the evaluations, available pharmacologic data, and management of HCV in patients with severe renal impairment, patients who underwent KT, and those who suffered from HCV-related renal disease, according to the available treatment options, including DAA.

Drug interactions with new hepatitis C oral drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has recently become a curable disease with antiviral therapy. The knowledge of drug interactions using direct-acting antivirals (DAA) may permit maximizing antiviral efficacy and avoiding drug-related toxicities. Ageing in the chronic hepatitis C population, along with added co-morbidities that require other medications, has increased the attention on drug interactions using DAA.

AREAS COVERED

This review provides an update of the most clinically significant pharmacokinetic and pharmacodynamic drug interactions occurring between currently available DAA and other medications. The review also revisits how drug interactions with DAA can be prevented and managed.

EXPERT OPINION

Interactions between DAA and other drugs are frequent in clinical practice. The most frequent drug interactions modify drug metabolism by inducing or inhibiting the cytochrome P450, leading to abnormal drug exposures. Through this mechanism HCV protease inhibitors, especially when co-formulated with ritonavir as pharmacoenhancer, and non-nucleoside HCV polymerase inhibitors interact with other medications. In contrast, NS5B nucleos(t)ide analog inhibitors (i.e., sofosbuvir) and some HCV NS5A inhibitors (i.e., ledipasvir), which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions. However, exposure to HCV nucleos(t)ide analogs may be influenced by induction/inhibition of drug transporters (i.e., P-glycoprotein) as well as by pharmacodynamic interference with other nucleos(t)ide analogs used as antivirals or cancer drugs. Drug interactions for some NS5A inhibitors (i.e., daclatasvir) are generally moderate and can be managed with dose adjustments.

Sofosbuvir and ribavirin for treatment of compensated recurrent hepatitis C virus infection after liver transplantation

BACKGROUND & AIMS

Interferon alfa-based regimens used to treat recurrent hepatitis C virus (HCV) infection after liver transplantation are poorly tolerated, associated with generally modest efficacy, and can interact with immunosuppressive agents. We evaluated the efficacy and safety of an interferon-free regimen of the nucleotide polymerase inhibitor sofosbuvir combined with ribavirin for 24 weeks in treating post-transplantation HCV infection.

METHODS

In a prospective, multicenter, open-label pilot study, we enrolled patients with compensated recurrent HCV infection of any genotype after a primary or secondary liver transplantation. All patients received 24 weeks of sofosbuvir 400 mg daily and ribavirin starting at 400 mg daily, which was adjusted according to creatinine clearance and hemoglobin values. The primary end point was sustained virologic response 12 weeks after treatment.

RESULTS

Of the 40 patients enrolled and treated, 78% were male, 85% were white, 83% had HCV genotype 1, 40% had cirrhosis (based on biopsy), and 88% had been previously treated with interferon. Sustained virologic response 12 weeks after treatment was achieved by 28 of 40 patients (70%; 90% confidence interval: 56%-82%). Relapse accounted for all cases of virologic failure. No patients had detectable viral resistance during or after treatment. The most common adverse events were fatigue (30%), diarrhea (28%), and headache (25%). In addition, 20% of the subjects experienced anemia. Two patients discontinued study treatment because of adverse events, which were considered unrelated to study treatment. No deaths, graft losses, or episodes of rejection occurred. No interactions with any concomitant immunosuppressive agents were reported.

CONCLUSIONS

Sofosbuvir and ribavirin combination therapy for 24 weeks is an effective and well-tolerated interferon-free treatment for post-transplantation HCV infection. EudraCT, Number: 2012-002417-19; ClinicalTrials.gov, Number: NCT01687270.

Use of simeprevir following pre-emptive pegylated interferon/ribavirin treatment for recurrent hepatitis C in living donor liver transplant recipients: a 12-week pilot study

BACKGROUND

The management of recurrent hepatitis C following liver transplantation remains a challenge.

METHODS

We prospectively investigated the efficacy and safety of simeprevir in combination with pegylated interferon and ribavirin in five patients undergoing living donor liver transplantation (LDLT) with recurrent hepatitis due to hepatitis C virus (HCV) genotype 1b.

RESULTS

As the immunosuppressive regimen, four received cyclosporine A (CsA) and one received tacrolimus (FK); no dose adjustment was made prior to the introduction of simeprevir, but the dose was accordingly modified afterwards. All five patients completed the intended 12-week treatment course without significant adverse events greater than grade 2, and no episodes of rejection were detected during the study period. The trough levels of CsA and FK were stably maintained. At week 12, HCV-RNA was not detectable in three of the five patients, whereas the HCV titer of the other two patients, including one with Q80L and V170I mutations at the HCV NS3 position, was at the lower level of quantification (1.2 log10 IU/ml).

CONCLUSIONS

Based on this pilot study, simeprevir-based triple therapy is safe and somewhat effective within the first 12 weeks in LDLT recipients with HCV recurrence. Further studies are warranted to obtain robust conclusions.

Hepatitis C virus infection and kidney transplantation in 2014: what's new?

Chronic hepatitis C virus (HCV) infection remains an important health problem, which is associated with deleterious consequences in kidney transplant recipients. Besides hepatic complications, several extrahepatic complications contribute to reduced patient and allograft survival in HCV-infected kidney recipients. However, HCV infection should not be considered as a contraindication for kidney transplantation because patient survival is better with transplantation than on dialysis. Treatment of HCV infection is currently interferon-alpha (IFN-α) based, which has been associated with higher renal allograft rejection rates. Therefore, antiviral treatment before transplantation is preferable. As in the nontransplant setting, IFN-free treatment regimens, because of their greater efficacy and reduced toxicity, currently represent promising and attractive therapeutic options after kidney transplantation as well. However, clinical trials will be required to closely evaluate these regimens in kidney recipients. There is also a need for prospective controlled studies to determine the optimal immunosuppressive regimens after transplantation in HCV-infected recipients. Combined kidney and liver transplantation is required in patients with advanced liver cirrhosis. However, in patients with cleared HCV infection and early cirrhosis without portal hypertension, kidney transplantation alone may be considered. There is some agreement about the use of HCV-positive donors in HCV-infected recipients, although data regarding posttransplant survival rates are controversial.

Management of Hepatitis C Before and After Liver Transplantation in the Era of Rapidly Evolving Therapeutic Advances

Management of hepatitis C (HCV) in liver transplantation (LT) population presents unique challenges. Suboptimal graft survival in HCV+ LT recipients is attributable to universal HCV recurrence following LT. Although eradication of HCV prior to LT is ideal for the prevention of HCV recurrence it is often limited by adverse events, particularly in patients with advanced cirrhosis. Antiviral therapy in LT candidates needs careful monitoring, and prophylaxis with HCV antibodies is ineffective. Early antiviral therapy after LT has been investigated, but no clear benefit has been demonstrated. Protocol liver biopsy is generally recommended in HCV+ LT recipients, and antiviral therapy can be considered in those with severe/progressive HCV recurrence. Sustained virological response (SVR) can be achieved in approximately 30% of LT recipients with pegylated interferon/ribavirin (PEG-IFN/RBV) with survival benefit, but adverse effects are common. Favorable patient characteristics for response to therapy include non-1 genotype, previously untreated, low baseline HCV-RNA, and donor IL28B genotype CC. Direct acting antiviral (DAA)-based triple therapy is associated with higher rates of SVR, but with similar or slightly higher rates of side effects, and immunosuppressive regimens need to be closely monitored and adjusted during the treatment period. Notably, the safety and efficacy of HCV treatment are very likely to improve with newer generation DAA. The benefit of immunosuppressive strategy on the natural history HCV recurrence has not been well elucidated. Based upon available evidence, cyclosporine A (CSA), mycophenolate mofetil (MMF), and sirolimus appear to have a neutral or small beneficial impact on HCV recurrence. Donor interleukin 28 B (IL28B) polymorphisms appear to impact the course and treatment outcomes in recurrent HCV. Retransplantation should be considered for patients with reasonable survival probability.