Telaprevir, boceprevir, cytochrome P450 and immunosuppressive agents--a potentially lethal cocktail

Special Considerations in the Management of HIV and Viral Hepatitis Coinfections in Liver Transplantation

Modern therapies for hepatitis B virus, hepatitis C virus, and human immunodeficiency virus have become so effective that patients treated for these conditions can have normal life-expectancies. Suitable livers for transplantation remain a scarce and valuable resource. As such, significant efforts have been made to expand donation criteria at many centers. This constant pressure, coupled with the increasing effectiveness of antiviral therapies, has meant that more and more patients infected with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) may be considered appropriate donors in the right circumstances. Patients with these infections are also more likely to be considered appropriate transplantation recipients than in the past. The treatment of HBV, HCV, and HIV after liver transplantation (LT) can be challenging and complicated by viral coinfections. The various pharmaceutical agents used to treat these infections, as well as the immunosuppressants used post-LT must be carefully balanced for maximum efficacy, and to avoid resistance and drug–drug interactions.

Treatment With Grazoprevir/Elbasvir for Renal Transplant Recipients With Chronic Hepatitis C Virus Infection and Impaired Allograft Function

BACKGROUND

Direct-acing antiviral agents are highly efficient treatment options for chronic hepatitis C virus (HCV) infection after renal allograft transplantation. Treatment options for patients with impaired graft function remain limited. Therefore, we assessed the effectiveness and safety of grazoprevir/elbasvir therapy for patients with chronic HCV infection and impaired renal allograft function.

METHODS

Eleven renal allograft recipients with therapy-naïve HCV genotype (GT) 1a, 1b, or 4 were treated with the fixed-dose combination of elbasvir/grazoprevir without ribavirin for 12 weeks. All recipients exhibited impaired graft function with an average glomerular filtration rate lower than 30 mL/min per 1.73 m2. Clinical data were retrospectively reviewed for renal and liver function parameters. Patients were closely monitored for trough levels of immunosuppressive agents, viral load, laboratory values, and potential adverse effects.

RESULTS

Seven (64%) patients exhibited a rapid virologic response within 4 weeks (HCV GT1a, n = 2; HCV GT1b, n = 5). The other 4 patients exhibited a virologic response within 8 weeks (HCV GT1b, n = 3; HCV GT 4, n = 1). All patients exhibited a sustained virologic response at week 12 after the end of treatment. Clinical measures of liver function improved substantially for all patients. Few adverse effects were reported. Impaired renal allograft function and proteinuria remained stable. For most patients, only moderate adjustments to the tacrolimus dosage were necessary for maintaining sufficient trough levels.

CONCLUSIONS

This treatment appears to be safe and effective for renal transplant recipients with impaired allograft function and is a promising treatment option for eradicating HCV infection in this patient population.

Pharmacokinetic Interaction between Faldaprevir and Cyclosporine or Tacrolimus in Healthy Volunteers: A Prospective, Open-Label, Fixed-Sequence, Crossover Study

Faldaprevir (FDV) is a potent, orally administered inhibitor of hepatitis C virus. In this single-centre, open-label, fixed-sequence, crossover study of 32 healthy adult male and female volunteers, subjects received either a single dose of cyclosporine (CsA) 50 mg (N = 16) or tacrolimus (TAC) 0.5 mg (N = 16), followed by a washout of at least 14 days. Each subject then received a loading dose of FDV 240 mg followed by 120 mg FDV once daily for 6 days. FDV 120 mg was then co-administered with an additional single dose of CsA (50 mg) or TAC (0.5 mg), followed by an additional 6 days of FDV 120 mg once daily. Intensive blood sampling was performed to assess the PK interaction potential. Assessment of relative BA indicated that exposure to CsA co-administered with FDV was similar to CsA alone. However, the AUC_τ,ss and C_max,ss of FDV were increased by 23% and 41%, respectively, when FDV was co-administered with CsA. Exposure to TAC was slightly increased (AUC_0-∞ increased by 27%, no change in C_max ) when TAC was co-administered with FDV. In contrast, exposure to FDV co-administered with TAC was similar to FDV alone. No unexpected safety findings arose from the trial. The limitations of the study (use of single, low dose of TAC and CsA, and only healthy volunteers in the trial) are discussed.

Real-world experience with daclatasvir plus sofosbuvir ± ribavirin for post-liver transplant HCV recurrence and severe liver disease

Optimizing therapy of post-transplant HCV recurrence remains important, especially in advanced liver disease. We evaluated daclatasvir (DCV) plus sofosbuvir (SOF), with or without ribavirin (RBV), in patients with post-liver transplant recurrence in a real-world European cohort at high risk of decompensation or death within 12 months. Recommended treatment was DCV 60 mg plus SOF 400 mg once daily for 24 weeks; RBV use/shorter treatment duration was at physicians' discretion. Patients (N = 87) were 70% male, 93% white, and mostly infected with HCV genotypes 1b (48%), 1a (32%), or 3 (9%); 37 (43%) had cirrhosis (16 decompensated), five had fibrosing cholestatic hepatitis. Sustained virologic response at post-treatment week 12 (SVR12) was 94% (80/85) in a modified intention-to-treat analysis: 95% (58/61) without RBV and 92% (22/24) with RBV, with no virologic failures. SVR12 was 100% (80/80) in an as-observed analysis excluding five nonvirologic failures. Four patients (5%) discontinued therapy for adverse events (AEs); 16 (18%) experienced serious AEs. One patient died on treatment and five during follow-up. Most AEs were associated with advanced liver disease and unrelated to therapy. No clinically significant drug-drug interactions were observed. DCV + SOF ± RBV was well tolerated and achieved high SVR12 (94%) in patients with post-transplant HCV recurrence, including patients with severe liver disease.

Hepatitis C in Liver Allograft Recipients: Utility of One-Year Post-Transplantation Biopsy as an Indicator of Antiviral Therapy

Background

All-oral interferon-free regimens for hepatitis C viral (HCV) infection are highly efficacious; however, high cost is a barrier to applicability. Liver allograft recipients are particularly likely to benefit from therapy as HCV often leads to graft dysfunction and loss. In this study, we aimed to establish the utility of allograft biopsy at 1 year post-transplant as an indicator of treatment.

Methods and Results

Among 252 liver recipients enrolled, 136 (54%) developed severe disease (fibrosing cholestatic hepatitis (FCH) or fibrosis stage ≥ 2 at 1 year post-transplant). Multivariable analysis revealed younger recipient age and female gender, older donor age and T cell depletive therapy to be independent predictors of severe disease. Recipients with severe disease had higher rate of further graft loss compared to those with mild disease. Patients with mild disease and sustained virologic response (SVR) had the best survival rate, whereas those with severe disease and viremia had the worst survival (96% versus 63% at 5 years).

Conclusion

In conclusion, allograft biopsy at 1 year helps identify recipients at high risk of further graft dysfunction and loss. In view of high cost of therapy, treatment should be preferably directed to high-risk patients including those with FCH or fibrosis stage ≥ 2 by 1 year post-transplant.

Simeprevir/pegylated interferon/ribavirin triple therapy for recurrent hepatitis C after living donor liver transplantation

AIM

Simeprevir (SMV) is a protease inhibitor which demonstrates good tolerability and high antiviral response in patients with hepatitis C. The clinical outcomes of triple therapy using simeprevir, pegylated interferon and ribavirin (SMV/PEG IFN/RBV) for recurrent hepatitis C after living donor liver transplantation (LDLT) have not been well reported. In this study, we assessed the outcomes of patients with recurrent hepatitis C (genotype 1) after LDLT who received triple therapy at our hospital.

METHODS

SMV/PEG IFN/RBV was administrated for 12 weeks (triple therapy), followed by another 12 weeks or extended period of PEG IFN/RBV (dual therapy). Virological response, interaction with calcineurin inhibitors and adverse events were retrospectively analyzed.

RESULTS

Ten patients with recurrent hepatitis C after LDLT completed 12 weeks of triple therapy. Nine patients achieved rapid or early virological response, and one patient was a non-responder. The nine responders received subsequent dual therapy, and the duration of dual therapy was extended (24 to 36 weeks) in five cases. Although one patient was in relapse 8 weeks after completing the standard duration (12 weeks) of dual therapy, eight patients achieved sustained virological response for 12 weeks (SVR12). The SVR12 rate was 80%. Trough levels of calcineurin inhibitor did not show marked changes after introduction of SMV in all cases. There were no major adverse events associated with SMV.

CONCLUSION

SMV treatment may be a safe and effective option for recurrent hepatitis C after LDLT.

CIHR Canadian HIV Trials Network Coinfection and Concurrent Diseases Core Research Group: 2016 Updated Canadian HIV/Hepatitis C Adult Guidelines for Management and Treatment

Background. Hepatitis C virus (HCV) coinfection occurs in 20-30% of Canadians living with HIV and is responsible for a heavy burden of morbidity and mortality. Purpose. To update national standards for management of HCV-HIV coinfected adults in the Canadian context with evolving evidence for and accessibility of effective and tolerable DAA therapies. The document addresses patient workup and treatment preparation, antiviral recommendations overall and in specific populations, and drug-drug interactions. Methods. A standing working group with HIV-HCV expertise was convened by The Canadian Institute of Health Research HIV Trials Network to review recently published HCV antiviral data and update Canadian HIV-HCV Coinfection Guidelines. Results. The gap in sustained virologic response between HCV monoinfection and HIV-HCV coinfection has been eliminated with newer HCV antiviral regimens. All coinfected individuals should be assessed for interferon-free, Direct Acting Antiviral HCV therapy. Regimens vary in content, duration, and success based largely on genotype. Reimbursement restrictions forcing the use of pegylated interferon is not acceptable if optimal patient care is to be provided. Discussion. Recommendations may not supersede individual clinical judgement. Treatment advances published since December 2015 are not considered in this document.

Activity-based and fraction-guided analysis of Phyllanthus urinaria identifies loliolide as a potent inhibitor of hepatitis C virus entry

Without a vaccine, hepatitis C virus (HCV) remains a global medical and socio-economic burden, predisposing about 170 million carriers worldwide to end-stage liver diseases including cirrhosis and hepatocellular carcinoma. Although the recently developed direct-acting antivirals (DAAs) have revolutionized hepatitis C treatment, most of them are unsuitable for monotherapy due to risks of resistance, thus necessitating combination with interferon (IFN)-alpha, ribavirin, or additional DAAs. More importantly, the high cost associated with the DAAs restricts their accessibility to most parts of the world. Developing novel cost-effective anti-HCV therapeutics may help expand the scope of antivirals and treatment strategies against hepatitis C. Herein, we applied an activity-based and fraction-guided analysis of extracts from the medicinal plant Phyllanthus urinaria (P. urinaria), which yielded fraction 13 (F13) as possessing the most potent inhibitory activity against early viral entry of cell-culture HCV infection. Chemical analysis (silica gel chromatography followed by ESI LC-MS plus (1)H and (13)C NMR) of F13 identified loliolide (LOD), a monoterpenoid lactone, as a novel inhibitor of HCV entry. Specifically, LOD could efficiently inactivate HCV free virus particles, abrogate viral attachment, and impede viral entry/fusion, with minimal effect on viral replication/translation, particle production, and induction of type I IFN host antiviral immune response. ELISA-based binding analysis confirmed the monoterpenoid's ability in efficiently blocking HCV particle attachment to the host cell surface. Furthermore, LOD could inhibit infection by several genotypic strains of HCV. This is the first report characterizing P. urinaria and its bioactive compound LOD as potent HCV entry inhibitors, which merit further evaluation for development as candidate antiviral agents against hepatitis C.

Daclatasvir, Simeprevir and Ribavirin as a Promising Interferon-Free Triple Regimen for HCV Recurrence after Liver Transplant

BACKGROUND

Recurrent hepatitis C infection after liver transplantation (LT) is associated with lower rates of graft and patient survival.

METHODS

Here we describe the first use of daclatasvir, simeprevir, and ribavirin (RBV) as an all-oral triple regimen administered to 6 liver transplant recipients with recurrent hepatitis C, one with GT 1a and 5 with GT 1b. All patients were treated for 24 weeks. Trough levels of immunosuppression, laboratory measures, and potential adverse effects were closely monitored.

RESULTS

For all patients, viral load became undetectable between treatment weeks 4 and 12. One patient experienced a viral breakthrough at the 10th week of treatment; this was associated with the selection of resistance-associated variants (D168Y in NS3 and ΔP32 in NS5A). For the other 5 patients, end-of-treatment response and for 4 patients SVR24 was achieved. Viremia recurred in one patient 4 weeks after the end of treatment, which was again associated with the selection of resistance-associated variants (D168V in NS3 and ΔP32 in NS5A). Clinical measures of liver function improved substantially for all patients. Adverse events were few and limited to moderate anemia caused by RBV. Importantly, adjustments to the immunosuppressant dosage were not required.

CONCLUSIONS

The described regimen appears to be safe and effective for liver transplant patients and will be a promising treatment regimen for post-LT patients.

Daily low-dose tacrolimus is a safe and effective immunosuppressive regimen during telaprevir-based triple therapy for hepatitis C virus recurrence after liver transplant

BACKGROUND

Graft loss because of hepatitis C virus recurrence is a serious problem after liver transplantation (LT), and the response to pegylated interferon (PEG-IFN) and ribavirin (RBV) is poor. The significantly better response rates achieved with telaprevir (TVR)-based triple therapy have led to better graft and patient survival rates, but severe drug interactions may limit the usefulness of this therapy for LT patients. We report our single-center experience with a specially developed protocol that involved administering a low daily dose of tacrolimus (TAC) to a cohort of 17 patients with a recurrence of hepatitis C virus genotype 1 after LT.

METHODS

Patients were treated with TVR, PEG-IFN, and RBV for 12 weeks, followed by 12 or 36 weeks of dual therapy with PEG-IFN and RBV. After TVR administration was initiated, the TAC dosage was skipped until trough levels began to decline; it was then administered at a dose of 0.1 mg once or twice daily. Tacrolimus trough levels and laboratory values were closely monitored during the TVR phase.

RESULTS

Deviations in trough levels were avoided, thus preventing any clinically evident renal toxicity related to TAC. In addition, histologic studies performed at the end of therapy showed that no rejection episodes had occurred. All patients tolerated the medication. Sustained virologic response was documented for 10 of 17 patients (58%) 24 weeks after end of treatment.

CONCLUSION

In conclusion, substantial dose reduction and daily administration of low doses of TAC compose a safe and efficient immunosuppressive regimen during TVR-based triple therapy.

Management of telaprevir-based triple therapy for hepatitis C virus recurrence post liver transplant

AIM: To characterize management of telaprevir (TVR)-based triple therapy of hepatitis C virus (HCV) reinfection after liver transplantation (LT).

METHODS: We retrospectively analyzed safety and efficacy of telaprevir - based triple therapy in a single center cohort of 19 patients with HCV genotype (GT) 1 recurrence after LT, with respect to factors possibly predicting sustained viral response (SVR) or non-SVR. All patients were treated with TVR, pegylated (PEG) and ribavirine (RBV) for 12 wk followed by a dual phase with PEG/RBV for 12 wk in 7 patients and for 36 wk in 5 patients.

RESULTS: In total 11/19 (58%) of patients achieved a sustained response. All (11/11) SVR patients showed a rapid viral response at treatment weeks 4 and 11/14 rapid virological response (RVR) patients achieved SVR. Notably, all (7/7) patients who completed 48 wk of therapy and 80% (4/5) patients who completed 24 wk of therapy achieved SVR24. Treatment failure was significantly (P > 0.049) more frequent in GT1a infection (5/7) compared to GT1b (3/12) infection and was associated with emergence of resistance-associated mutations in the NS3 protease domain. Bilirubin level at baseline is also related to SVR (P > 0.030). None of the patients had to discontinue treatment due to side effects.

CONCLUSION: RVR, GT and bilirubin are clearly related to achievement of SVR. Providing a thorough patient selection and monitoring, a full course of TVR-based triple therapy in LT patients is feasible and achieves high SVR rates.

New therapies for hepatitis C: considerations in patients with renal impairment

Hepatitis C virus (HCV) is a major public health issue because infection may lead to liver failure, cirrhosis and hepatocellular carcinoma. In patients with renal dysfunction, hepatitis C can also worsen the underlying renal disease. Treating HCV infection is thus mandatory in this population. New therapies for hepatitis C have recently been developed, and some have been launched. Most of them are used in combination with the current standard of care, ribavirin and pegylated interferon alfa. Some of them can be used in regimens without ribavirin and/or pegylated interferon. However, few data are available on dosage adjustment for renal function in patients receiving these very new drugs. We reviewed the literature on this subject and gathered information, although scarce, to propose guidelines for using these drugs in patients with chronic kidney disease.

The pharmacokinetics of daclatasvir and asunaprevir administered in combination in studies in healthy subjects and patients infected with hepatitis C virus

BACKGROUND AND OBJECTIVES

The combination of direct-acting antiviral agents in patients with chronic hepatitis C virus (HCV) infection has demonstrated clinical benefit; however, evaluation of potential drug-drug interactions is required prior to therapy.

METHODS

An open-label study assessed the pharmacokinetics and tolerability of the HCV NS5A replication complex inhibitor daclatasvir and the HCV NS3 protease inhibitor asunaprevir when co-administered in healthy subjects. Daclatasvir 60 mg once daily and asunaprevir 600 mg twice daily were dosed for 7 days alone followed by combination dosing for 14 days at 30 mg once daily and 200 mg twice daily, respectively. Further assessments were provided comparing exposures from the current study with those from studies in HCV-infected patients receiving either the same or higher doses of daclatasvir or asunaprevir administered alone or together.

RESULTS

Dose-normalized daclatasvir and asunaprevir morning exposures were comparable with control in healthy subjects, with geometric mean area under the concentration-time curve ratios of 1.202 (90 % CI 1.113-1.298) and 0.868 (90 % CI 0.726-1.038), respectively. In HCV patients daclatasvir and asunaprevir exposures were largely comparable, when administered together or alone.

CONCLUSIONS

Additional data support the conclusion that there is no clinically meaningful interaction between daclatasvir and asunaprevir in either healthy subjects or HCV-infected patients, including those also receiving peginterferon-α/ribavirin, and that the combination of daclatasvir 60 mg once daily and asunaprevir 200 mg twice daily is generally well-tolerated.

Hepatitis C virus reinfection after liver transplant: New chances and new challenges in the era of direct-acting antiviral agents

The first interferon-free regimens have been approved for the treatment of patients with chronic hepatitis C virus (HCV). In the liver transplant (LT) setting, these regimens are expected to have an important effect, because graft loss due to HCV recurrence is a serious problem after LT. The response to the hitherto conventional treatment with pegylated interferon and ribavirin is poor. The significantly better response rates achieved with boceprevir-based and telaprevir-based triple therapy have led to better graft and patient survival rates, but severe drug interactions with immunosuppressants limit the feasibility of this therapy for LT patients. With the approval of sofosbuvir in January 2014, of simeprevir in May 2014, and of daclatasvir in August 2014, three antiviral agents are now available and promise to be applicable without relevant adverse effects or negative interactions with immunosuppressants. Thus, 2014 marks the beginning of a new era of treatment options for HCV recurrence after LT. Although safety and efficacy studies of several interferon-free regimens for patients with HCV recurrence after LT have achieved good preliminary results, reports of clinical experiences with LT patients are scarce. The lack of randomized studies, the small number of enrolled and carefully selected patients, and the heterogeneity of these studies make the results questionable. Real-life experiences are eagerly awaited so that clinicians can estimate the usefulness and the pitfalls of these new regimens. Additionally, the high costs of these agents may limit their accessibility for many patients. The aim of this review is to summarize the current experience with and the expectations of the new direct-acting antiviral agents for LT patients.

Hepatitis C

Hepatitis C virus (HCV) infection is a major health problem worldwide. The effects of chronic infection include cirrhosis, end-stage liver disease, and hepatocellular carcinoma. As a result of shared routes of transmission, co-infection with HIV is a substantial problem, and individuals infected with both viruses have poorer outcomes than do peers infected with one virus. No effective vaccine exists, although persistent HCV infection is potentially curable. The standard of care has been subcutaneous interferon alfa and oral ribavirin for 24-72 weeks. This treatment results in a sustained virological response in around 50% of individuals, and is complicated by clinically significant adverse events. In the past 10 years, advances in HCV cell culture have enabled an improved understanding of HCV virology, which has led to development of many new direct-acting antiviral drugs that target key components of virus replication. These direct-acting drugs allow for simplified and shortened treatments for HCV that can be given as oral regimens with increased tolerability and efficacy than interferon and ribavirin. Remaining obstacles include access to appropriate care and treatment, and development of a vaccine.

Synergy of entry inhibitors with direct-acting antivirals uncovers novel combinations for prevention and treatment of hepatitis C

OBJECTIVE

Although direct-acting antiviral agents (DAAs) have markedly improved the outcome of treatment in chronic HCV infection, there continues to be an unmet medical need for improved therapies in difficult-to-treat patients as well as liver graft infection. Viral entry is a promising target for antiviral therapy.

DESIGN

Aiming to explore the role of entry inhibitors for future clinical development, we investigated the antiviral efficacy and toxicity of entry inhibitors in combination with DAAs or other host-targeting agents (HTAs). Screening a large series of combinations of entry inhibitors with DAAs or other HTAs, we uncovered novel combinations of antivirals for prevention and treatment of HCV infection.

RESULTS

Combinations of DAAs or HTAs and entry inhibitors including CD81-, scavenger receptor class B type I (SR-BI)- or claudin-1 (CLDN1)-specific antibodies or small-molecule inhibitors erlotinib and dasatinib were characterised by a marked and synergistic inhibition of HCV infection over a broad range of concentrations with undetectable toxicity in experimental designs for prevention and treatment both in cell culture models and in human liver-chimeric uPA/SCID mice.

CONCLUSIONS

Our results provide a rationale for the development of antiviral strategies combining entry inhibitors with DAAs or HTAs by taking advantage of synergy. The uncovered combinations provide perspectives for efficient strategies to prevent liver graft infection and novel interferon-free regimens.

Lack of drug interaction between cyclosporine and telaprevir in a liver transplant recipient

Telaprevir is a novel NS3A/4A protease inhibitor approved in combination with ribavirin and peg-interferon alfa for the treatment of genotype-1 chronic hepatitis C. This drug is also known to be a potent cytochrome P450 3A and drug efflux protein ATP-binding cassette B1 (also called P-glycoprotein) inhibitor, and could therefore interact with immunosuppressive drugs. For this reason, a decrease in cyclosporine (CsA) dosage has been proposed when combining this drug with telaprevir. We report herein the case of an unpredictable lack of interaction between CsA and telaprevir in a liver transplant recipient. The decrease in CsA dosage, conducted as recommended in the literature, did not result in stable CsA concentrations but decreased them. However, the decrease in CsA exposure could have been unseen without the measurement of CsA concentrations 2 h after the administration (C2 ) of the drug, because it mainly resulted from the decrease in CsA peak. The mechanism leading to this lack of drug interaction in this patient has not been fully elucidated yet, but is likely to affect the absorption phase. Therapeutic drug monitoring using only CsA trough concentrations could be falsely reassuring, and the addition of the measurement of the C2 may add useful information to adapt CsA dosage in patients co-treated with telaprevir.

An interferon-free antiviral regimen for HCV after liver transplantation

BACKGROUND

Hepatitis C virus (HCV) infection is the leading indication for liver transplantation worldwide, and interferon-containing regimens are associated with low response rates owing to treatment-limiting toxic effects in immunosuppressed liver-transplant recipients. We evaluated the interferon-free regimen of the NS5A inhibitor ombitasvir coformulated with the ritonavir-boosted protease inhibitor ABT-450 (ABT-450/r), the nonnucleoside NS5B polymerase inhibitor dasabuvir, and ribavirin in liver-transplant recipients with recurrent HCV genotype 1 infection.

METHODS

We enrolled 34 liver-transplant recipients with no fibrosis or mild fibrosis, who received ombitasvir-ABT-450/r (at a once-daily dose of 25 mg of ombitasvir, 150 mg of ABT-450, and 100 mg of ritonavir), dasabuvir (250 mg twice daily), and ribavirin for 24 weeks. Selection of the initial ribavirin dose and subsequent dose modifications for anemia were at the investigator's discretion. The primary efficacy end point was a sustained virologic response 12 weeks after the end of treatment.

RESULTS

Of the 34 study participants, 33 had a sustained virologic response at post-treatment weeks 12 and 24, for a rate of 97% (95% confidence interval, 85 to 100). The most common adverse events were fatigue, headache, and cough. Five patients (15%) required erythropoietin; no patient required blood transfusion. One patient discontinued the study drugs owing to adverse events after week 18 but had a sustained virologic response. Blood levels of calcineurin inhibitors were monitored, and dosages were modified to maintain therapeutic levels; no episode of graft rejection was observed during the study.

CONCLUSIONS

Treatment with the multitargeted regimen of ombitasvir-ABT-450/r and dasabuvir with ribavirin was associated with a low rate of serious adverse events and a high rate of sustained virologic response among liver-transplant recipients with recurrent HCV genotype 1 infection, a historically difficult-to-treat population. (Funded by AbbVie; CORAL-I ClinicalTrials.gov number, NCT01782495.).

Recurrent HCV after liver transplantation-mechanisms, assessment and therapy

Chronic HCV infection is the leading indication for liver transplantation. However, as a result of HCV recurrence, patient and graft survival after liver transplantation are inferior compared with other indications for transplantation. HCV recurrence after liver transplantation is associated with considerable mortality and morbidity. The development of HCV-related fibrosis is accelerated after liver transplantation, which is influenced by a combination of factors related to the virus, donor, recipient, surgery and immunosuppression. Successful antiviral therapy is the only treatment that can attenuate fibrosis. The advent of direct-acting antiviral agents (DAAs) has changed the therapeutic landscape for the treatment of patients with HCV. DAAs have improved tolerability, and can potentially be used without PEG-IFN for a shorter time than previous therapies, which should result in better outcomes. In this Review, we describe the important risk factors that influence HCV recurrence after liver transplantation, highlighting the mechanisms of fibrosis and the integral role of hepatic stellate cells. Indirect and direct assessment of fibrosis, in addition to new antiviral therapies, are also discussed.

Impact of lipids and lipoproteins on hepatitis C virus infection and virus neutralization

Hepatitis C virus (HCV) infections represent a major global health problem. End-stage liver disease caused by chronic HCV infection is a major indication for liver transplantation. However, after transplantation the engrafted liver inevitably becomes infected by the circulating virus. Direct acting antivirals are not yet approved for use in liver transplant patients, and limited efficacy and severe side effects hamper the use of pegylated interferon combined with ribavirin in a post-transplant setting. Therefore, alternative therapeutic options need to be explored. Viral entry represents an attractive target for such therapeutic intervention. Understanding the mechanisms of viral entry is essential to define the viral and cellular factors involved. The HCV life cycle is dependent of and associated with lipoprotein physiology and the presence of lipoproteins has been correlated with altered antiviral efficacy of entry inhibitors. In this review, we summarise the current knowledge on how lipoprotein physiology influences the HCV life cycle. We focus especially on the influence of lipoproteins on antibodies that target HCV envelope proteins or antibodies that target the cellular receptors of the virus. This information can be particularly relevant for the prevention of HCV re-infection after liver transplantation.

Prevention of hepatitis C virus infection by adoptive allogeneic immunotherapy using suicide gene-modified lymphocytes: an in vitro proof-of-concept

Hepatitis C virus (HCV)-induced, end-stage liver disease is a major indication for liver transplantation, but systematic graft reinfection accelerates liver disease recurrence. Transplantation recipients may be ineligible for direct-acting antivirals, owing to toxicity, resistance or advanced liver disease. Adoptive immunotherapy with liver graft-derived, ex vivo-activated lymphocytes was previously shown to prevent HCV-induced graft reinfections. Alternatively, the applicability and therapeutic efficacy of adoptive immunotherapy may be enhanced by 'ready for use' suicide gene-modified lymphocytes from healthy blood donors; moreover, conditional, prodrug-induced cell suicide may prevent potential side effects. Here, we demonstrate that allogeneic suicide gene-modified lymphocytes (SGMLs) could potently, dose- and time-dependently, inhibit viral replication. The effect occurs at effector:target cell ratios that exhibits no concomitant cytotoxicity toward virus-infected target cells. The effect, mediated mostly by CD56+ lymphocytes, is interleukin-2-dependent, IFN-γ-mediated and, importantly, resistant to calcineurin inhibitors. Thus, post-transplant immunosuppression may not interfere with this adoptive cell immunotherapy approach. Furthermore, these cells are indeed amenable to conditional cell suicide; in particular, the inducible caspase 9 suicide gene is superior to the herpes simplex virus thymidine kinase suicide gene. Our data provide in vitro proof-of-concept that allogeneic, third-party, SGMLs may prevent HCV-induced liver graft reinfection.

Two patients treated with pegylated interferon/ribavirin/telaprevir triple therapy for recurrent hepatitis C after living donor liver transplantation

It is difficult to use protease inhibitors in patients with recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) due to interaction with immunosuppressive drugs. We report our experience with two patients treated with telaprevir (TVR) combined with pegylated interferon/ribavirin (PEG IFN/RBV) for recurrent HCV genotype 1 infection after LT. The first was a 63-year-old man with HCV-related liver cirrhosis, who failed to respond to IFN-β plus RBV after LT. Treatment was switched to PEG IFN-α-2b plus RBV and TVR was started. The donor had TT genotype of interleukin (IL)-28 single nucleotide polymorphisms (SNP) (rs8099917). The recipient had TT genotype of IL-28 SNP (rs8099917). Completion of 12-week triple therapy was followed by PEG IFN-α-2b plus RBV for 36 weeks. Finally, he had sustained viral response. The second was a 70-year-old woman with HCV-related liver cirrhosis and hepatocellular carcinoma. She failed to respond to PEG IFN-α-2b plus RBV after LT, and was subsequently switched to PEG IFN-α-2b/RBV/TVR. Genotype analysis showed TG genotype of IL-28 SNP for the donor, and TT genotype of IL-28 SNP for the recipient. Serum HCV RNA titer decreased below the detection limit at 5 weeks. However, triple therapy was withdrawn at 11 weeks due to general fatigue, which resulted in HCV RNA rebound 4 weeks later. Both patients were treated with cyclosporin, starting with a small dose to avoid interactions with TVR. TVR is a potentially suitable agent for LT recipients who do not respond to PEG IFN-α-2b plus RBV after LT.

Successful anti-scavenger receptor class B type I (SR-BI) monoclonal antibody therapy in humanized mice after challenge with HCV variants with in vitro resistance to SR-BI-targeting agents

Hepatitis C virus (HCV)-induced endstage liver disease is currently a major indication for liver transplantation. After transplantation the donor liver inevitably becomes infected with the circulating virus. Monoclonal antibodies (mAbs) against the HCV coreceptor scavenger receptor class B type I (SR-BI) inhibit HCV infection of different genotypes, both in cell culture and in humanized mice. Anti-SR-BI mAb therapy is successful even when initiated several days after HCV exposure, supporting its potential applicability to prevent HCV reinfection of liver allografts. However, HCV variants with reduced SR-BI dependency have been described in the literature, which could potentially limit the use of SR-BI targeting therapy. In this study we show, both in a preventative and postexposure setting, that humanized mice infected with HCV variants exhibiting increased in vitro resistance to SR-BI-targeting molecules remain responsive to anti-SR-BI mAb therapy in vivo. A 2-week antibody therapy readily cleared HCV RNA from the circulation of infected humanized mice. We found no evidence supporting increased SR-BI-receptor dependency of viral particles isolated from humanized mice compared to cell culture-produced virus. However, we observed that, unlike wild-type virus, the in vitro infectivity of the resistant variants was inhibited by both human high density lipoprotein (HDL) and very low density lipoprotein (VLDL). The combination of mAb1671 with these lipoproteins further increased the antiviral effect.

CONCLUSION

HCV variants that are less dependent on SR-BI in vitro can still be efficiently blocked by an anti-SR-BI mAb in humanized mice. Since these variants are also more susceptible to neutralization by anti-HCV envelope antibodies, their chance of emerging during anti-SR-BI therapy is severely reduced. Our data indicate that anti-SR-BI receptor therapy could be an effective way to prevent HCV infection in a liver transplant setting.

[Drug-drug interaction with telaprevir or boceprevir in liver transplant patients: about four cases]

Boceprevir and telaprevir are both direct-acting antivirals indicated, as part of combination therapy for the management of chronic hepatitis C virus (HCV) genotype 1 infection. Transplanted patients treated with anticalcineurines (tacrolimus and cyclosporine) are confronted with major risks of interactions. Indeed, these antiviral are strong inhibitors of the enzyme cytochrome 3A4/A5, responsible for the metabolisme of ciclosprine and tacrolimus. The literature gives evidence of the dangerousness of this drug-drug interaction. We report four clinical cases illustrating the dosage adaptations at liver transplant patients and treated by telaprevir or boceprevir. To protect the immunosuppressive efficiency, a multidisciplinary care and narrow monitoring of the interaction between immunosuppressing agents and protease inhibitors were necessary.

Review article: 2014 UK consensus guidelines - hepatitis C management and direct-acting anti-viral therapy

BACKGROUND

Therapeutic options for the management of hepatitis C virus (HCV) infection have evolved rapidly over the past two decades, with a consequent improvement in cure rates. Novel therapeutic agents are an area of great interest in the research community, with a number of these agents showing promise in the clinical setting.

AIMS

To assess and present the available evidence for the use of novel therapeutic agents for the treatment of HCV, updating previous guidelines.

METHODS

All Phase 2 and 3 studies, as well as abstract presentations from international Hepatology meetings were identified and reviewed for suitable inclusion, based on studies of new therapies in HCV. Treatment-naïve and experienced individuals, as well as cirrhotic and co-infected individuals were included.

RESULTS

Sofosbuvir, simeprevir and faldaprevir, along with pegylated interferon and ribavirin, have a role in the treatment of chronic HCV infection. The precise regimens are largely dependent on the patient characteristics, patient and physician preferences, and cost implication.

CONCLUSIONS

Therapies for chronic HCV have evolved dramatically in recent years. Interferon-free regimens are now possible without compromise in the rate of sustained viral response. The decision as to which regimen is most appropriate is multifactorial, and based on efficacy, safety and cost.

Safety and efficacy of protease inhibitors to treat hepatitis C after liver transplantation: a multicenter experience

BACKGROUND & AIMS

Protease inhibitors (PI) with peginterferon/ribavirin have significantly improved SVR rates in HCV G1 patients. Their use to treat HCV recurrence after liver transplantation (LT) is a challenge.

METHODS

This cohort study included 37 liver transplant recipients (male, 92%, age 57 ± 11 years), treated with boceprevir (n=18) or telaprevir (n=19). The indication for therapy was HCV recurrence (fibrosis stage ≥F2 (n=31, 83%) or fibrosing cholestatic hepatitis (n=6, 16%).

RESULTS

Eighteen patients were treatment-naive, five were relapsers and fourteen were non-responders to dual therapy after LT. Twenty-two patients received cyclosporine and fifteen tacrolimus. After 12 weeks of PI therapy, a complete virological response was obtained in 89% of patients treated with boceprevir, and 58% with telaprevir (p=0.06). The end of treatment virological response rate was 72% (13/18) in the boceprevir group and 40% (4/10) in the telaprevir group (p=0.125). A sustained virological response 12 weeks after treatment discontinuation was observed in 20% (1/5) and 71% (5/7) of patients in the telaprevir and boceprevir groups, respectively (p=0.24). Treatment was discontinued in sixteen patients (treatment failures (n=11), adverse events (n=5)). Infections occurred in ten patients (27%), with three fatal outcomes (8%). The most common adverse effect was anemia (n=34, 92%), treated with erythropoietin and/or a ribavirin dose reduction; thirteen patients (35%) received red blood cell transfusions. The cyclosporine dose was reduced by 1.8 ± 1.1-fold and 3.4 ± 1.0-fold with boceprevir and telaprevir, respectively. The tacrolimus dose was reduced by 5.2 ± 1.5-fold with boceprevir and 23.8±18.2-fold with telaprevir.

CONCLUSIONS

Our results suggest that triple therapy is effective in LT recipients, particularly those experiencing a severe recurrence. The occurrence of anemia and drug-drug interactions, and the risk of infections require close monitoring.

Recurrent hepatitis C virus infection and outcome after living-donor liver transplant

OBJECTIVES

In living-donor liver transplant recipients with hepatitis C virus infection, outcomes of recurrent hepatitis C virus infection and fibrosis progression are not well documented. We evaluated fibrosis progression, response to pegylated interferon treatment, and long-term graft survival in living-donor liver transplant recipients who had hepatitis C virus infection.

MATERIALS AND METHODS

In 48 transplant recipients, including 29 recipients who had follow-up liver biopsy ≥ 6 months after transplant, histology and clinical courses were reviewed. Outcomes were evaluated for patients grouped into slow and rapid fibrosis groups. Treatment with pegylated interferon and ribavirin was assessed in 18 patients.

RESULTS

Clinical features were similar between recipients with slow or rapid fibrosis. The time interval from transplant to recurrence of hepatitis C virus infection was significantly shorter in the recipients with rapid fibrosis. Recipients with rapid fibrosis had significantly greater confluent necrosis, acidophil bodies, and fibrosis score than recipients with slow fibrosis. Graft survival rates were similar between patients with slow or rapid fibrosis. Cumulative proportion of long-term graft survival was 60% at 7 years after transplant. Sustained virologic response was noted in 5 of 18 patients (28%) who received pegylated interferon and ribavirin.

CONCLUSIONS

In recipients of living-donor liver transplant with early recurrence of hepatitis C have worse fibrosis progression but graft survival was not affected. Therapy with pegylated interferon and ribavirin achieved sustained virologic response only in a small proportion of the patients.

A small-molecule inhibitor of hepatitis C virus infectivity

One of the most challenging goals of hepatitis C virus (HCV) research is to develop well-tolerated regimens with high cure rates across a variety of patient populations. Such a regimen will likely require a combination of at least two distinct direct-acting antivirals (DAAs). Combining two or more DAAs with different resistance profiles increases the number of mutations required for viral breakthrough. Currently, most DAAs inhibit HCV replication. We recently reported that the combination of two distinct classes of HCV inhibitors, entry inhibitors and replication inhibitors, prolonged reductions in extracellular HCV in persistently infected cells. We therefore sought to identify new inhibitors targeting aspects of the HCV replication cycle other than RNA replication. We report here the discovery of the first small-molecule HCV infectivity inhibitor, GS-563253, also called HCV infectivity inhibitor 1 (HCV II-1). HCV II-1 is a substituted tetrahydroquinoline that selectively inhibits genotype 1 and 2 HCVs with low-nanomolar 50% effective concentrations. It was identified through a high-throughput screen and subsequent chemical optimization. HCV II-1 only permits the production and release of noninfectious HCV particles from cells. Moreover, infectious HCV is rapidly inactivated in its presence. HCV II-1 resistance mutations map to HCV E2. In addition, HCV-II prevents HCV endosomal fusion, suggesting that it either locks the viral envelope in its prefusion state or promotes a viral envelope conformation change incapable of fusion. Importantly, the discovery of HCV II-1 opens up a new class of HCV inhibitors that prolong viral suppression by HCV replication inhibitors in persistently infected cell cultures.

Epidermal growth factor receptor signaling impairs the antiviral activity of interferon-alpha

Interferon-alpha (IFN-α) exhibits its antiviral activity through signal transducer and activator of transcription protein (STAT) signaling and the expression of IFN response genes (IRGs). Viral infection has been shown to result in activation of epidermal growth factor receptor (EGFR)-a host cell entry factor used by several viruses, including hepatitis C virus. However, the effect of EGFR activation for cellular antiviral responses is unknown. Here, we uncover cross-talk between EGFR and IFN-α signaling that has a therapeutic effect on IFN-α-based therapies and functional relevance for viral evasion and IFN resistance. We show that combining IFN-α with the EGFR inhibitor, erlotinib, potentiates the antiviral effect of each compound in a highly synergistic manner. The extent of the synergy correlated with reduced STAT3 phosphorylation in the presence of erlotinib, whereas STAT1 phosphorylation was not affected. Furthermore, reduced STAT3 phosphorylation correlated with enhanced expression of suppressors of cytokine signaling 3 (SOCS3) in the presence of erlotinib and enhanced expression of the IRGs, radical S-adenosyl methionine domain containing 2 and myxovirus resistance protein 1. Moreover, EGFR stimulation reduced STAT1 dimerization, but not phosphorylation, indicating that EGFR cross-talk with IFN signaling acts on the STATs at the level of binding DNA.

CONCLUSIONS

Our results support a model where inhibition of EGFR signaling impairs STAT3 phosphorylation, leading to enhanced IRG expression and antiviral activity. These data uncover a novel role of EGFR signaling in the antiviral activity of IFN-α and open new avenues of improving the efficacy of IFN-α-based antiviral therapies.

[Pharmacokinetic interactions of telaprevir with other drugs]

Telaprevir is a new direct-acting antiviral drug for the treatment of hepatitis C virus (HCV) infection and is both a substrate and an inhibitor of cytochrome P450 (CYP450) isoenzymes. With the introduction of this new drug, assessment of drug-drug interactions has become a key factor in the evaluation of patients under treatment for HCV infection. During the treatment of this infection, many patients require other drugs to mitigate the adverse effects of anti-HCV drugs and to control other comorbidities. Moreover, most patients coinfected with HIV and HCV require antiretroviral therapy during treatment for HCV. Physicians should therefore be familiar with the pharmacokinetic properties of direct-acting antivirals for HCV treatment and their potential drug-drug interactions. The present article reviews the available information to date on the interactions of telaprevir with other drugs and provides recommendations for daily clinical practice.

Therapy of chronic hepatitis C virus infection in the era of direct-acting and host-targeting antiviral agents

OBJECTIVES

Chronic hepatitis C virus (HCV) infection represents a leading worldwide medical and social problem. The expanding knowledge of HCV lifecycle has led to the development of novel antiviral agents that: a) specifically target a viral function (direct-acting antivirals), or b) specifically inhibit viral replication. The present review describes the novel anti-HCV drugs that have been better studied at the time of this writing and the current two types of treatment, namely interferon-based and interferon-free regimens. In addition, predictive factors, virological responses, side-effects, and resistance mechanisms of the novel agents are summarized.

CONCLUSIONS

The introduction of novel antiviral agents is remarkably changing the therapeutic combinations aimed at improving virological responses both for easy-to-cure and difficult-to-treat patients. Since additional, effective drugs are under advanced development, it seems reasonable to expect that further therapeutic and prognostic improvements will be achieved in the near future.

Multicenter experience using telaprevir or boceprevir with peginterferon and ribavirin to treat hepatitis C genotype 1 after liver transplantation

The safety, efficacy, and effect on immunosuppression levels of telaprevir (TVR) or boceprevir (BOC) in combination with peginterferon (PEG-IFN) and ribavirin (RBV) in recipients of liver transplantation (LT) with hepatitis C virus (HCV) genotype 1 have not been defined. We report our 3 centers' preliminary experiences with administering triple antiviral treatment protocols containing PEG-IFN, RBV, and TVR or BOC. Patients with biopsy-proven HCV recurrence (METAVIR grade ≥ 3 and/or stage ≥ 2) received TVR with PEG-IFN/RBV for 12 weeks and then PEG-IFN/RBV for 36 weeks or BOC with PEG-IFN/RBV for 44 weeks after 4 weeks of lead-in PEG-IFN/RBV. Maintenance immunosuppression was changed to cyclosporine whenever possible, and the levels were followed closely. PEG-IFN/RBV dose adjustments were based on patients' tolerance. Sixty patients started triple antiviral treatment, and they were followed for up to 66 weeks (mean = 35 weeks); all were followed at least 12 weeks. Thirty of the 35 patients treated with TVR (86%) achieved undetectable HCV RNA levels after an average of 6 weeks, whereas 12 patients (48%) in the BOC-treated group achieved undetectable HCV RNA levels after a mean of 11 weeks. According to an intention-to-treat analysis, 14 of 21 TVR-treated patients (67%) and 10 of 22 patients who received BOC (45%) achieved undetectable HCV RNA levels at week 24 without viral breakthrough at the last follow-up. Cytopenias complicated both regimens; all patients required dose reductions of PEG-IFN and/or RBV or the administration of hematological growth factors. One death occurred in each group on triple antiviral treatment. In conclusion, TVR or BOC combined with PEG-IFN/RBV achieved on-treatment virological response rates of approximately 50% to 60% in patients with recurrent HCV after LT, but significant side effects were common.

Combinations of simple baseline variables accurately predict sustained virological response in patients with recurrent hepatitis C after liver transplantation

BACKGROUND

The efficacy of antiviral therapy in patients with hepatitis C recurrence after liver transplantation (LT) is far from optimal and a careful selection of candidates with the best chances to achieve sustained virological response (SVR) is relevant. Moreover, investigating the effects of sustained viral clearance on clinical outcomes is particularly significant. We aimed to identify and combine the best baseline predictors of SVR and to assess the clinical outcomes of antiviral therapy after LT.

METHODS

We studied 144 hepatitis C virus (HCV)-infected LT recipients who underwent antiviral therapy following transplantation. Baseline predictors of SVR including donor and recipient interleukin IL28B (IL28B) rs12979860 genotype were evaluated, and the long-term effects of antiviral therapy on clinical outcomes were assessed.

RESULTS

The presence of an IL28B CC genotype with either low viral load (VL), young donor age, or cyclosporine A (CsA)-based immunosuppression identified individuals with 69-80 % probabilities of SVR. In contrast, only 20% of recipients with a CT/TT IL28B genotype and either high VL, old donor age, or non-CsA immunosuppression achieved an SVR (p = 0.004). Regarding clinical outcomes, the 5-year cumulative probability of graft loss was 2% for the SVR patients and 48% for non-responders (p < 0.001).

CONCLUSIONS

The use of simple combinations of baseline variables including IL28B polymorphisms identifies HCV-infected LT recipients with different probabilities of response to antiviral treatment. SVR is associated with improved clinical outcomes.

A novel monoclonal anti-CD81 antibody produced by genetic immunization efficiently inhibits Hepatitis C virus cell-cell transmission

BACKGROUND AND AIMS

Hepatitis C virus (HCV) infection is a challenge to prevent and treat because of the rapid development of drug resistance and escape. Viral entry is required for initiation, spread, and maintenance of infection, making it an attractive target for antiviral strategies.

METHODS

Using genetic immunization, we produced four monoclonal antibodies (mAbs) against the HCV host entry factor CD81. The effects of antibodies on inhibition of HCV infection and dissemination were analyzed in HCV permissive human liver cell lines.

RESULTS

The anti-CD81 mAbs efficiently inhibited infection by HCV of different genotypes as well as a HCV escape variant selected during liver transplantation and re-infecting the liver graft. Kinetic studies indicated that anti-CD81 mAbs target a post-binding step during HCV entry. In addition to inhibiting cell-free HCV infection, one antibody was also able to block neutralizing antibody-resistant HCV cell-cell transmission and viral dissemination without displaying any detectable toxicity.

CONCLUSION

A novel anti-CD81 mAb generated by genetic immunization efficiently blocks HCV spread and dissemination. This antibody will be useful to further unravel the role of virus-host interactions during HCV entry and cell-cell transmission. Furthermore, this antibody may be of interest for the development of antivirals for prevention and treatment of HCV infection.

Differential effects of donor and recipient IL28B and DDX58 SNPs on severity of HCV after liver transplantation

BACKGROUND & AIMS

IL28B single nucleotide polymorphisms are strongly associated with spontaneous HCV clearance and treatment response in non-transplant populations. A DDX58 single nucleotide polymorphism is associated with the antiviral response of innate lymphocytes. We aimed at evaluating the associations of donor and recipient IL28B (rs12979860 and rs8099917) and DDX58 (rs10813831) genotypes with severity of HCV recurrence after liver transplantation.

METHODS

In a case-control study of 523 liver transplantation recipients with HCV, we matched severe with mild recurrent HCV based on 2-year clinical and histologic follow-up. A total of 440 liver transplantation recipients (severe, n=235; mild, n=205) with recipient DNA and 225 (severe, n=123; mild, n=102) with both recipient and donor DNA were analyzed.

RESULTS

IL28B [rs12979860, non-CC (vs. CC) and rs8099917, non-TT (vs. TT)] in the recipient-only analysis had higher risk of severe recurrent HCV [OR 1.57 and 1.58, p<0.05]. However, for the 225 with donor and recipient DNA, IL28B rs12979860 CC (vs. non-CC) and rs8099917 TT (vs. non-TT) and DDX58 rs10813831 non-GG (vs. GG) were associated with more (not less) severe recurrent HCV. The greatest risk of severe recurrent HCV was for rs12979860 CC donors in non-CC recipients (OR 7.02, p <0.001, vs. non-CC donor/recipient) and for rs8099917 TT donors in non-TT recipients (OR 5.78, p=0.001, vs. non-TT donor/recipient). These associations persisted after controlling for donor age, donor race, and donor risk index.

CONCLUSIONS

IL28B and DDX58 single nucleotide polymorphisms that are favorable when present in the non-transplant setting or in the recipient are unfavorable when present in a donor liver graft.

Clinical management of drug-drug interactions in HCV therapy: challenges and solutions

Hepatitis C virus (HCV) infected patients often take multiple co-medications to treat adverse events related to HCV therapy, or to manage other co-morbidities. Drug-drug interactions associated with this polypharmacy are relatively new to the field of HCV pharmacotherapy. With the advent of the direct-acting antivirals telaprevir and boceprevir, which are both substrates and inhibitors of the cytochrome P450 (CYP) 3A iso-enzyme, knowledge and awareness of drug-drug interactions have become a cornerstone in the evaluation of patients starting and continuing HCV combination therapy. In our opinion, an overview of conducted drug-drug interaction studies and a list of contraindicated medications is not enough for the clinical management of these drug-drug interactions. Knowledge of pharmacokinetic profiles and concentration-effect relationships is key for the interpretation of these data, and insight into how to manage these interactions (e.g., dose adjustments, safe alternatives and therapeutic drug monitoring) is of equal importance. This review provides a practical overview of the safe and effective management of these clinical challenges.

An update on the management of hepatitis C: guidelines for protease inhibitor-based triple therapy from the Latin American Association for the Study of the Liver

Hepatitis C is a common cause of end-stage liver disease, and the main indication for liver transplantation in Latin America. Treatment of hepatitis C infected patients improves important long-term outcomes as mortality. Sustained viral response is reached in near 50% of patients with the previous management based in pegylated interferon and ribavirin. Recently new drugs were available increasing sustained viral response significantly, changing the standard of care to triple therapy. This guidelines provides a framework for practitioner in Latin America, to the management of patients with hepatitis C chronic infection. 

Safety and anti-HCV effect of prolonged intravenous silibinin in HCV genotype 1 subjects in the immediate liver transplant period

BACKGROUND & AIMS

Reinfection of the graft is the rule in patients with HCV cirrhosis undergoing liver transplantation, and HCV-RNA reaches pre-transplantation levels within the first month. Short-term intravenous silibinin monotherapy is safe and shows a potent in vivo anti-HCV effect. We aimed at evaluating the safety and antiviral effect of prolonged intravenous silibinin, started immediately before liver transplantation.

METHODS

Single centre, prospective, pilot study, to assess the safety and effect on HCV-RNA kinetics during at least 21 days of intravenous silibinin monotherapy (20 mg/kg/day) in 9 consecutive HCV genotype 1 subjects, in comparison to a control, non-treated group of 7 consecutive prior transplanted subjects under the same immunosuppressive regimen (basiliximab, steroids, delayed tacrolimus, micophenolate).

RESULTS

Intravenous silibinin led to significant, maintained and progressive HCV-RNA decreases (mean HCV-RNA drop at week 3, -4.1 ± 1.3 log(10)IU/ml), and lack of viral breakthrough during administration. Four patients (44%) reached negative HCV-RNA, maintained during silibinin treatment, vs. none in the control group, but HCV-RNA relapsed in all of them after a median of 21 days (16-28), following silibinin withdrawal. Partial responders to silibinin showed marked decreases in HCV-RNA when compared to controls, but lower than complete responders. There were no clinical adverse effects, and silibinin led to asymptomatic transient hyperbilirubinemia (week 2, 4.2 ± 2.2 vs. 2.5 ± 3.6 mg/dl; p=0.02).

CONCLUSIONS

Prolonged intravenous silibinin monotherapy was safe in the immediate liver transplantation period, leading to a potent and time dependent antiviral effect and lack of HCV-RNA breakthrough during administration. However, HCV-RNA rebounded after withdrawal, and silibinin monotherapy did not avoid reinfection of the graft.

CIHR Canadian HIV Trials Network Coinfection and Concurrent Diseases Core: Canadian guidelines for management and treatment of HIV/hepatitis C coinfection in adults

BACKGROUND

Hepatitis C virus (HCV) coinfection occurs in 20% to 30% of Canadians living with HIV, and is responsible for a heavy burden of morbidity and mortality. HIV-HCV management is more complex due to the accelerated progression of liver disease, the timing and nature of antiretroviral and HCV therapy, mental health and addictions management, socioeconomic obstacles and drug-drug interactions between new HCV direct-acting antiviral therapies and antiretroviral regimens.

OBJECTIVE

To develop national standards for the management of HCV-HIV coinfected adults in the Canadian context.

METHODS

A panel with specific clinical expertise in HIV-HCV co-infection was convened by The CIHR HIV Trials Network to review current literature, existing guidelines and protocols. Following broad solicitation for input, consensus recommendations were approved by the working group, and were characterized using a Class (benefit verses harm) and Level (strength of certainty) quality-of-evidence scale.

RESULTS

All HIV-HCV coinfected individuals should be assessed for HCV therapy. Individuals unable to initiate HCV therapy should initiate antiretroviral therapy to slow liver disease progression. Standard of care for genotype 1 is pegylated interferon and weight-based ribavirin dosing plus an HCV protease inhibitor; traditional dual therapy for 24 weeks (for genotype 2/3 with virological clearance at week 4); or 48 weeks (for genotypes 2-6). Therapy deferral for individuals with mild liver disease may be considered. HIV should not be considered a barrier to liver transplantation in coinfected patients.

DISCUSSION

Recommendations may not supersede individual clinical judgement.

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.

Understanding the switchbacks: the impact of direct antivirals on the minimization of hepatitis C virus recurrence after transplantation

1. Interferon (IFN) and ribavirin can be used in select patients before or after liver transplantation, and they can reduce the risk of recurrence or effect a cure in these settings. 2. Currently licensed direct-acting antiviral drugs are used with IFN and ribavirin, so the safety and tolerability of triple therapy will be worse than those of double therapy in pretransplant and posttransplant settings. 3. Drug-drug interactions [exemplified by the interactions of protease inhibitors (PIs) with tacrolimus and cyclosporine] and the need for dose modifications (exemplified by the need to modify ribavirin doses in patients with renal dysfunction) challenge the safe use of antiviral drugs after transplantation. 4. Experience with the use of human immunodeficiency virus PIs and emerging data about hepatitis C virus (HCV) PIs show that this class of drugs can be used with care after transplantation. 5. Attempts to prevent HCV graft infections through the use of HCV immunoglobulin immediately after transplantation have been largely unsuccessful. 6. The blockade of cell surface HCV receptors with antibodies or small molecules appears to limit HCV cell entry in vivo and in a mouse model, and this may suggest a novel approach to limiting HCV recurrence at the time of transplantation.

Boceprevir: a protease inhibitor for the treatment of hepatitis C

BACKGROUND

Boceprevir is a protease inhibitor indicated for the treatment of chronic hepatitis C virus (HCV) genotype 1 infection in combination with peginterferon and ribavirin for treatment-naive patients and those who previously failed to improve with interferon and ribavirin treatment.

OBJECTIVE

This article provides an overview of the mechanism of action, pharmacologic and pharmacokinetic properties, clinical efficacy, and tolerability of boceprevir.

METHODS

Relevant information was identified through a search of PubMed (1990-July 2012), EMBASE (1990-July 2012), International Pharmaceutical Abstracts (1970-July 2012), and Google Scholar using the key words boceprevir, SCH 503034, non-structural protein 3 (NS3) serine protease inhibitor, and direct-acting antiviral agent (DAA). Additional information was obtained from the US Food and Drug Administration's Web site, review of the reference lists of identified articles, and posters and abstracts from scientific meetings.

RESULTS

Clinical efficacy of boceprevir was assessed in 2 Phase III trials, Serine Protease Inhibitor Therapy-2 (SPRINT-2) for treatment-naive patients and Retreatment with HCV Serine Protease Inhibitor Boceprevir and PegIntron/Rebetol 2 (RESPOND-2) for treatment-experienced patients. In SPRINT-2, patients were randomized to receive peginterferon + ribavirin (PR) or peginterferon + ribavirin + boceprevir (PRB); duration of boceprevir therapy varied from 24, 32, to 44 weeks on the basis of HCV RNA results. The primary endpoint was achievement of sustained virologic response (SVR; lower limit of detection, 9.3 IU/mL). The addition of boceprevir was shown to be superior, with overall SVR rates ranging from 63% to 66% compared with 38% with PR (P < 0.001). Results of SVR in SPRINT-2 were also reorganized to monitor SVRs in black and non-black patients. Treatment-experienced patients were assessed in RESPOND-2; however, null responders were excluded. Patients were again randomized to PR or PRB; duration of boceprevir therapy varied from 32 to 44 weeks on the basis of HCV RNA results. SVR was significantly higher in patients receiving boceprevir (59%-66% vs 21% with PR; P < 0.001). This benefit was seen in both previous nonresponders (SVR, 40%-52% vs 7% with PR), as well as previous relapsers (SVR, 69%-75% vs 29% with PR). Importantly, SVR could be attained with a shortened course of therapy in almost one half of all treated patients in SPRINT-2 (44%) and RESPOND-2 (46%).

CONCLUSIONS

Boceprevir was well tolerated in clinical trials and a welcomed addition to our HCV armamentarium.

Peginterferon-α-2b and ribavirin for hepatitis C recurrence postorthotopic liver transplantation

GOALS

To evaluate the safety and efficacy of peginterferon-α-2b plus ribavirin in patients with recurrent hepatitis C after orthotopic liver transplant.

BACKGROUND

Reinfection of liver allografts in hepatitis C virus -infected transplant recipients begins immediately after transplantation. Treatment of these patients is challenging because of poor tolerability.

STUDY

A multicenter, open-label study enrolling patients with persistent viremia after primary orthotopic liver transplant for cirrhosis related to hepatitis C virus infection. Patients received peginterferon-α-2b (1.5 µg/kg/wk) plus ribavirin (400 to 1200 mg/d administered using a dose-escalating regimen and according to body weight) for 48 weeks. The primary endpoint was sustained virologic response (SVR).

RESULTS

In total, 125 patients started treatment and 58.4% completed 48 weeks. SVR rate was 28.8% (G1, 23.8%; G2/3, 55.0%), end-of-treatment response rate was 40.8%, and relapse rate was 18.2%. SVR was 55% among patients who completed treatment. Genotype 2/3 infection, male sex, baseline hemoglobin>14 g/dL, 80:80:80 compliance, rapid virologic response (RVR), and complete early virologic response (cEVR) were predictors of SVR. SVR was higher among patients with RVR compared with those without RVR (83.3% vs. 25.7%; P=0.0098), and among patients with cEVR compared with those without EVR (66.7% vs. 1.8%; P<0.0001). Thirty-eight patients discontinued because of an adverse event and 69 required dose reduction or interruption. Anemia (74%) and neutropenia (30%) were common, and rejection was low (3.2%).

CONCLUSIONS

SVR was low in this study. Anemia was a particular challenge in achieving maximal ribavirin therapeutic exposure and may account in part for the lower SVR.

Practical management of boceprevir and immunosuppressive therapy in liver transplant recipients with hepatitis C virus recurrence

Hepatitis C virus (HCV) recurrence is the most important complication in HCV liver transplant patients. Boceprevir with pegylated interferon and ribavirin (PegIFN/RBV) enabled improvement in sustained virological response rates of patients with genotype 1 HCV. Boceprevir interacts with immunosuppressive therapy (IT) by inhibiting the cytochrome P450 3A enzyme. Our aim was to study interactions and assess the safety of boceprevir in the context of HCV recurrence. Boceprevir (800 mg three times a day) initiated after a 4-week lead-in phase was associated with cyclosporine (three patients), tacrolimus (two patients), and everolimus (one patient) in five liver transplant patients with genotype 1 HCV infection who experienced HCV recurrence. The mean follow-up period after HCV therapy was 14.8 ± 3.1 weeks. Estimated oral clearances of IT decreased on average by 50%, requiring reduced dosing regimens. Anemia occurred in all patients, with a mean fall in hemoglobin levels between baseline and week 12 of 3.12 ± 2.27 g/dl. All patients required administration of β-erythropoietin (n = 5), three needed ribavirin dose reduction, and one needed a blood transfusion. A virological response was observed in all patients (mean HCV viral load [HVL] decrease at week 12, 6.64 ± 0.35 log(10) IU/ml). These preliminary results in liver transplant patients with HCV recurrence demonstrate the feasibility and safety of coadministration of boceprevir and IT.

Liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

Novel human SR-BI antibodies prevent infection and dissemination of HCV in vitro and in humanized mice

BACKGROUND & AIMS

Hepatitis C virus (HCV)-induced end-stage liver disease is currently the major indication for liver transplantation in the Western world. After transplantation, the donor liver almost inevitably becomes infected by the circulating virus and disease progression is accelerated in immune suppressed transplant patients. The current standard therapy, based on pegylated interferon and ribavirin, induces severe side effects and is often ineffective in this population. Therefore, new strategies to prevent graft re-infection are urgently needed. We have previously shown that monoclonal antibodies (mAbs) against the HCV co-receptor scavenger receptor class B type I (SR-BI/Cla1) inhibit infection by different HCV genotypes in cell culture.

METHODS

Using phage display libraries, we have generated a large set of novel human mAbs against SR-BI and evaluated their effectiveness in preventing HCV infection and direct cell-to-cell spread in vitro and in vivo using uPA-SCID mice with a humanized liver.

RESULTS

Eleven human monoclonal antibodies were generated that specifically recognize SR-BI. Two antibodies, mAb8 and mAb151, displayed the highest binding and inhibitory properties and also interfered with direct cell-to-cell spread in vitro. Studies in humanized mice showed that both antibodies were capable of preventing HCV infection and could block intrahepatic spread and virus amplification when administered 3 days after infection. Interestingly, anti-SR-BI therapy was effective against an HCV variant that escaped the control of the adaptive immune response in a liver transplant patient.

CONCLUSIONS

The anti-SR-BI mAbs generated in this study may represent novel therapeutic tools to prevent HCV re-infection of liver allografts.

Telaprevir: a review of its use in the management of genotype 1 chronic hepatitis C

Telaprevir (Incivo®, Incivek®), an orally administered inhibitor of the hepatitis C virus non-structural protein NS3-4A serine protease, is used in combination with pegylated interferon (peginterferon)-alpha and ribavirin in the treatment of adults with genotype 1 chronic hepatitis C virus (HCV) infection (chronic hepatitis C). This article reviews data on the clinical efficacy and tolerability of telaprevir in adults with genotype 1 chronic hepatitis C and provides a summary of its pharmacological properties. In in vitro studies, telaprevir shows good activity against genotype 1 HCV, including viral isolates from patients with chronic hepatitis C. Numerous resistant variants of HCV have been identified in clinical isolates from patients receiving treatment with telaprevir-based therapy. However, the clinical relevance of viral variants emerging during treatment requires further study. Telaprevir administered for 12 weeks in combination with peginterferon-alpha-2a and ribavirin for up to 48 weeks was effective in the treatment of previously untreated or previously treated adults with genotype 1 chronic hepatitis C in three major randomized phase III trials. Sustained virological response rates (i.e. percentages of patients with undetectable HCV RNA levels 24 weeks after the last planned dose of study medication: the primary endpoint) achieved with the telaprevir-based regimens were significantly higher than those produced with peginterferon-alpha-2a and ribavirin alone (the 'current standard of care'). In the largest trial (the ADVANCE trial) in previously untreated patients, 24 weeks after the last planned dose of study drug, recipients of 12 weeks' treatment with telaprevir in combination with peginterferon-alpha-2a and ribavirin followed by treatment with peginterferon-alpha-2a and ribavirin for a further 12 or 36 weeks experienced significantly (p < 0.001) higher sustained virological response rates than patients who received peginterferon-alpha-2a and ribavirin dual therapy for 48 weeks (75% vs 44%). Adverse events were reported more frequently with telaprevir-based regimens than with peginterferon-alpha-2a and ribavirin dual therapy in the major trials. The most common adverse events included fatigue, rash, pruritus, anaemia and nausea. In conclusion, telaprevir in combination with peginterferon-alpha and ribavirin is an effective treatment for treatment-naive and previously treated adults with genotype 1 chronic hepatitis C - patient groups in whom peginterferon-alpha and ribavirin dual therapy may not be successful. Thus, telaprevir is a valuable new treatment option for use in combination with peginterferon-alpha and ribavirin in treatment-naive or previously treated adults with genotype 1 chronic hepatitis C.

Failure of Intravenous Silibinin Monotherapy to Prevent Hepatitis C Genotype 2A Liver Graft Reinfection

BACKGROUND

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) remains a serious problem in the clinical management of post-oLT patients. Recently, two case reports have described successful prevention of HCV liver graft reinfection with intravenous silibinin (SIL) monotherapy in two carriers of genotype 3a and 1a/4 HCV. Based on these findings, we decided to offer such a therapy to a 65 year old woman on the oLT list.

CASE PRESENTATION

A 65 year old patient with HCV 2a cirrhosis, a previous relapse to PegIFn and Rbv therapy, was listed for oLT due to hepatocellular carcinoma. She started SIL monotherapy 24 hours before oLT. After an initial HCV-RnA decline following surgery,a progressive HCV RnA increase was observed. For this reason, SIL was stopped after 15 days of monotherapy.

CONCLUSIONS

SIL has multiple anti-HCV mechanisms of action, most of them have been characterized in vitro only. Our case report shows that the antiviral effect of SIL might be HCV genotype dependent, as recently suggested by a study, showing no effect of SIL on the HCV-2a subgenomic replicon model. our case reinforces the need for controlled studies to assess the efficacy of silibinin therapy in HCV infected patients before it can be broadly used in all clinical settings.