Management of hepatitis C virus in the transplant patient

Pharmacokinetics and dose recommendations for cyclosporine and tacrolimus when coadministered with ABT-450, ombitasvir, and dasabuvir

ABT-450, ombitasvir, and dasabuvir are direct-acting antiviral agents (DAAs) that have been developed for combination treatment of chronic hepatitis C virus (HCV) infection. Because these DAAs have metabolic and transporter profiles that overlap with cyclosporine and tacrolimus disposition, there is potential for drug interactions. Two Phase 1 studies assessed effects of ABT-450 (150 mg coadministered with ritonavir 100 mg once daily), ombitasvir (25 mg once daily), and dasabuvir (400 mg twice daily) on the pharmacokinetics, safety, and tolerability of a single dose of cyclosporine (30 mg) or tacrolimus (2 mg) in healthy volunteers (N = 12 per study). In the presence of steady-state concentrations of all 3 DAAs, dose-normalized cyclosporine concentration at 24 hours (C₂₄), and area under the concentration-time curve from time 0 to infinity (AUC(∞)) were 15.8-fold and 5.8-fold, respectively, and dose-normalized tacrolimus C₂₄ and AUC(∞) were 17-fold and 57-fold, respectively, of either agent alone. Cyclosporine and tacrolimus half-lives increased from 7 to 25 h and 32 to 232 h, respectively. There were no major safety or tolerability issues in these studies. The results suggest that cyclosporine and tacrolimus doses and dosing frequency should be reduced in HCV-infected posttransplant patients being treated with this 3-DAA regimen.

Antiviral activity and safety profile of silibinin in HCV patients with advanced fibrosis after liver transplantation: a randomized clinical trial

Response to interferon-based therapies in HCV recurrence after liver transplantation (LT) is unsatisfactory, and major safety issues aroused in preliminary experience with boceprevir and telaprevir. As transplant community identified HCV viral clearance as a critical matter, efficacious and safe anti-HCV therapies are awaited. The aim of this study was to assess efficacy and safety of intravenous silibinin monotherapy in patients with established HCV recurrence after LT, nonresponders to pegylated interferon and ribavirin. This is a single center, prospective, randomized, parallel-group, double-blind, placebo-controlled, phase 2 trial including 20 patients randomly assigned (3:1) to receive daily 20 mg/kg of intravenous silibinin or saline as placebo, for 14 consecutive days. On day 14 of treatment, viral load decreased by 2.30 ± 1.32 in silibinin group versus no change in the placebo group (P = 0.0002). Sixteen days after the end of the treatment, viral load mean values were similar to baseline. Treatment resulted well tolerated apart from a transient and reversible increase in bilirubin. Neither changes in immunosuppressant through levels nor dosage adjustments were necessary. Silibinin monotherapy has a significant antiviral activity in patients with established HCV recurrence on the graft not responding to standard therapy and confirms safety and tolerability without interaction with immunosuppressive drugs (ClinicalTrials.gov number: NCT01518933).

Hepatitis C recurrence: the Achilles heel of liver transplantation

Hepatitis C virus (HCV) infection is the most common indication for liver transplantation worldwide; however, recurrence post transplant is almost universal and follows an accelerated course. Around 30% of patients develop aggressive HCV recurrence, leading to rapid fibrosis progression (RFP) and culminating in liver failure and either death or retransplantation. Despite many advances in our knowledge of clinical risks for HCV RFP, we are still unable to accurately predict those most at risk of adverse outcomes, and no clear consensus exists on the best approach to management. This review presents a critical overview of clinical factors shown to influence the course of HCV recurrence post transplant, with particular focus on recent data identifying the important role of metabolic factors, such as insulin resistance, in HCV recurrence. Emerging data for genetic markers of HCV recurrence and their usefulness for predicting adverse outcomes will also be explored.

Influence of antiviral therapy in the long-term outcome of recurrent hepatitis C virus infection following liver transplantation

INTRODUCTION

Severity of recurrent hepatitis C virus (HCV) infection in liver transplant recipients (LTR) is variable and the influence of different factors, including the administration of antiviral therapy in the long-term outcome is controversial.

METHODS

We analyzed the outcome of a cohort of HCV-infected LTR who were transplanted in our institution. Patients were divided into 2 groups (severe and non-severe HCV disease) depending on the presence of a fibrosis score of F ≥ 2 in the Scheuer index and/or fibrosing cholestasic hepatitis (FCH) in a graft biopsy. Risk factors were studied using logistic regression analysis. Survival of patients was estimated using Kaplan-Meier plots. A total of 146 patients were followed for a mean of 58 months.

RESULTS

Fifty-six (34%) patients developed severe HCV disease and showed shorter survival (P < 0.024). Donor age (odds ratio [OR]: 1.04; 95% confidence interval [CI]: 1.02-1.06) and pre-transplant viral load (VL) >10(6) UI/mL (OR: 3.5; 95% CI: 1.42-10.61) were the only factors associated with severe HCV infection. Over-immunosuppression (OR: 2.3; 95% CI: 1.2-4.41) was specifically associated with the development of FCH. Overall, patient survival in recipients who received a full course of anti-HCV therapy was higher than in patients who did not complete antiviral therapy (P = 0.004) or received no treatment (P = 0.007). Patients with non-severe HCV infection have a higher probability of receiving a full course of antiviral therapy (P = 0.033).

CONCLUSION

In conclusion, donor age, pre-transplant VL, and over-immunosuppression were associated with the long-term development of severe HCV recurrence in liver grafts. Administration of a full course of antiviral therapy was associated with better survival.

New and Evolving Management Paradigms for Hepatitis C after Liver Transplantation

Hepatitis-C induced liver failure is the leading indication for liver transplantation in the United States, and the burden of hepatitis C virus (HCV)-induced liver disease is not expected to peak for at least another decade. 2011 will usher in a new era of directly acting antiviral therapies and personalized medicine that will assist patients and clinicians in choosing the best drug regimen. Specific markers to predict sustained virologic response (SVR) in the posttransplant setting are under development, and the role of graft genetic markers like interleukin-28B and interferon-γ inducible protein-10 have yet to be fully defined. Lessons and experiences from treating the pretransplant population will be applied to patients with recurrent posttransplant HCV while studies specific to this population proceed. New paradigms for HCV treatment give promise to reducing the pretransplant burden of disease and improving SVR rates in the posttransplant population.

Effect of telaprevir on the pharmacokinetics of cyclosporine and tacrolimus

The hepatitis C virus protease inhibitor telaprevir is an inhibitor of the enzyme cytochrome P450 3A, responsible for the metabolism of both cyclosporine and tacrolimus. This Phase I, open-label, nonrandomized, single-sequence study assessed the effect of telaprevir coadministration on the pharmacokinetics of a single dose of either cyclosporine or tacrolimus in two separate panels of 10 healthy volunteers each. In Part A, cyclosporine was administered alone as a single 100-mg oral dose, followed by a minimum 8-day washout period, and subsequent coadministration of a single 10-mg oral dose of cyclosporine with either a single dose of telaprevir (750 mg) or with steady-state telaprevir (750 mg every 8 hours [q8h]). In Part B, tacrolimus was administered alone as a single 2-mg oral dose, followed by a minimum 14-day washout period, and subsequent coadministration of a single 0.5-mg dose of tacrolimus with steady-state telaprevir (750 mg q8h). Coadministration with steady-state telaprevir increased cyclosporine dose-normalized (DN) exposure (DN_AUC(0-∞)) by approximately 4.6-fold and increased tacrolimus DN_AUC(0-∞) by approximately 70-fold. Coadministration with telaprevir increased the terminal elimination half-life (t(½)) of cyclosporine from a mean (standard deviation [SD]) of 12 (1.67) hours to 42.1 (11.3) hours and t(½) of tacrolimus from a mean (SD) of 40.7 (5.85) hours to 196 (159) hours.

CONCLUSION

In this study, telaprevir increased the blood concentrations of both cyclosporine and tacrolimus significantly, which could lead to serious or life-threatening adverse events. Telaprevir has not been studied in organ transplant patients; its use in these patients is not recommended because the required studies have not been completed to understand appropriate dose adjustments needed for safe coadministration of telaprevir with cyclosporine or tacrolimus, and regulatory approval has not been obtained.

Hepatitis C and kidney transplantation

Hepatitis C virus (HCV) infection is relatively common among patients with end-stage kidney disease (ESKD) on dialysis and kidney transplant recipients. HCV infection in hemodialysis patients is associated with an increased mortality due to liver cirrhosis and hepatocellular carcinoma. The severity of hepatitis C-related liver disease in kidney transplant candidates may predict patient and graft survival after transplant. Liver biopsy remains the gold standard in the assessment of liver fibrosis in this setting. Kidney transplantation, not haemodialysis, seems to be the best treatment for HCV+ve patients with ESKD. Transplantation of kidneys from HCV+ve donors restricted to HCV+ve recipients is safe and associated with a reduction in the waiting time. Simultaneous kidney/liver transplantation (SKL) should be considered for kidney transplant candidates with HCV-related decompensated cirrhosis. Treatment of HCV is more complex in hemodialysis patients, whereas treatment of HCV recurrence in SLK recipients appears effective and safe.

Flexible and individualized treatment to achieve sustained viral response for recurrent hepatitis C in liver transplant recipients

Hepatitis C recurrence after liver transplantation is universal and is a major cause of long-term graft failure. Improving the effectiveness of recurrent hepatitis C treatment is extremely important. We studied 35 anti-hepatitis C virus (HCV)-positive patients who underwent liver transplantation. Among the 35 patients, 25 patients had recurrent hepatitis C and received antiviral treatment. HCV RNA load after liver transplantation was increased by 3.68-fold. The antiviral treatment regimen comprised pegylated-interferon (180 μg) every 2 weeks and ribavirin at a dose of 200-400 mg every day. The treatment duration was flexible and individualized, and depended on viral response to treatment. The dosage of tacrolimus was decreased gradually to minimize immunocompromise. Median (interquartile) serum level of tacrolimus was 6.9 (6-8.9) ng/mL at initiation of treatment and 3.8 (3.6-5) ng/mL at the end of treatment. One patient (4.0%) was withdrawn from the study, and three patients (12%) died of infection during treatment. At end of treatment, 18 of 25 patients (72%) were negative for serum HCV RNA. After an additional 6 months following the end of treatment, 16 of the 25 patients (64%) had sustained viral response (SVR) and only two patients had HCV relapse. The 1-year, 3-year and 5-year survival rates were 91.4%, 84.5% and 84.5% for all patients and 88.0%, 82.8% and 82.8% for the 25 patients who received antiviral therapy. In conclusion, recurrent HCV infection is an important issue in liver transplantation. The flexible regimen of antiviral therapy and individualized immunosuppressive agents that was applied in this study achieved a SVR rate of 64%.

A clinical assessment of mycophenolate drug monitoring after liver transplantation

BACKGROUND

Recent findings have suggested the clinical utility of therapeutic drug monitoring (TDM) in patients treated with mycophenolate mofetil (MMF).

AIM

To assess whether routine mycophenolic acid (MPA) TDM is beneficial and how to utilize it.

METHODS

A series of short-term prospective studies on TDM for MPA and/or tacrolimus was performed at a large-volume center.

RESULTS

The 673 adult liver transplants were divided into four groups based on immunosuppressive regimens as tacrolimus monotherapy (n = 369), tacrolimus-MMF therapy (n = 270), MMF-minimal tacrolimus therapy (n = 17), and MMF monotherapy (n = 17). There was a significant difference of tacrolimus concentration between the groups receiving tacrolimus monotherapy and tacrolimus-MMF therapy during the first two yr (at two yr: 8.4 +/- 2.7 vs. 6.3 +/- 2.6 ng/mL; p < or = 0.002). MMF-minimal tacrolimus therapy and MMF monotherapy were applied after first three months and MPA levels ranged from 1.8 to 5.3 microg/mL. Correlation between MMF dosage and MPA concentration showed wide interindividual variations (n = 304, r(2) = 0.271, p < 0.001), in which r(2) was fluctuating from 0.056 to 0.213 according to the post-transplant period over five yr; wide intraindividual variation was also observed during the first two months (n = 12, r(2) < 0.2, p > 0.195). About 10% of patients were classified as poor MMF absorber and excluded from MMF usage. Mean MPA level leading to successful MMF monotherapy or MMF-minimal tacrolimus therapy was > or =1.0 microg/mL in 87% and >2.0 microg/mL in 56.5%.

CONCLUSION

MPA TDM-based MMF dosage adjustment enabled us to administer MMF more confidently than categorical dosing. MPA TDM appears to be a useful tool to cope with the wide pharmacokinetic variability of MMF after liver transplantation.

[Hepatitis C recurrence after living donor and cadaveric liver transplantation]

OBJECTIVE

To determine the recurrence of hepatitis C in patients subjected to living donor liver transplantation compared to those subjected to cadaveric liver transplantation.

METHODS

Of a total of 333 liver transplantations, 279 (83.8%) were cadaveric liver transplantation and 54 (16.2%) living donor liver transplantation. Hepatic cirrhosis due to hepatitis C virus was the most common indication of both cadaveric liver transplantation (82 patients) and living donor liver transplantation (19 patients). The electronic study protocols of all patients with hepatic cirrhosis due to hepatitis C virus were reviewed. All data, including patients' age and sex, laboratory tests, hepatitis C virus recurrence and acute rejection were evaluated statistically.

RESULTS

A total of 55 cadaveric liver transplantation and 10 living donor liver transplantation performed in patients with liver cirrhosis due to hepatitis C virus was included in the study. Clinical and laboratory characteristics of the two groups before the transplantation were similar, except for the prothrombin time that was higher for the cadaveric liver transplantation than the living donor liver transplantation (P = 0.04). Hepatitis C virus recurrence was similar in the cadaveric liver transplantation (n = 37; 69.3%) and living donor liver transplantation (n = 7; 70%) groups (P = 0.8). The incidence of acute rejection was similar in cadaveric liver transplantation (n = 27; 49%) and living donor liver transplantation (n = 2; 20%) groups (P = 0.08). Hepatitis C virus recurrence in patients of the cadaveric liver transplantation group who received bolus doses of corticosteroids (9 of 11 patients) was similar to the remained patients (28 of 44 patients) (P = 0.25). Recurrence was also similar in patients of the living donor liver transplantation group who received bolus doses of corticosteroids (one of one patient) in relation to those who did not receive them (six of nine patients) (P = 0.7).

CONCLUSION

Hepatitis C recurrence is similar in patients who underwent living donor liver transplantation or cadaveric liver transplantation.

Management of liver transplant recipients with recurrent hepatitis C

PURPOSE OF REVIEW

Hepatitis C virus infection is the leading indication for liver transplantation, with recurrent hepatitis C almost universal. Although posttransplant treatment of hepatitis C virus infection remains suboptimal, active investigation continues to inform patient selection and risk-benefit analysis.

RECENT FINDINGS

Several key studies have identified components in the immunological response that are associated with the necroinflammatory and fibrotic response. Hepatitis C virus infection is associated with a higher rate of diabetes mellitus after transplant. Patients with diabetes and metabolic syndrome have poorer outcomes, and aggressive management is necessary. Differentiation of acute rejection from recurrent hepatitis C is difficult; however, the use of hepatitis C virus RNA tissue levels, immunohistochemistry and Councilman body/portal tract ratio may help with this diagnostic dilemma. The use of a specific calcineurin inhibitor appears not to influence recurrent hepatitis C, but rapid steroid taper is detrimental and, if steroids are used, long slow taper should be used. Use of rapid and early virological responses is very helpful in the management of hepatitis C after transplantation. In the patients with sustained virological response, histological and survival benefits are noted.

SUMMARY

The present review highlights advances in our understanding of the pathophysiology and treatment of hepatitis C virus infection after liver transplantation in the last few years.

Impact of the donor risk index on the outcome of hepatitis C virus-positive liver transplant recipients

We have investigated the impact of the donor risk index (DRI) on the outcome of hepatitis C virus (HCV)-infected patients undergoing liver transplantation (LTx). Retrospective analysis was performed from the Organ Procurement and Transplantation Network database (January 1, 2000 to June, 2006). The DRI was calculated as described by Feng et al. (Am J Transplant 2006;6:783-790). Model for End-Stage Liver Disease (MELD) exceptions were excluded from the analysis. Relative risk (RR) estimates of patient and graft loss were derived from Cox regression models. The Wald test was used to test the effect of the MELD score at transplant on the HCV-DRI interaction. Of the LTx recipients (16,678), 76.1% were Caucasian, and 66.7% were male; the median age was 52 (range, 18-80 years), and the mean follow-up time was 1148 days (range, 0-2959 days). Forty-six percent (n = 7675) of LTx recipients were HCV(+). The median DRI was 1.3 (range, 0.77-4.27). Increasing DRI was associated with a statistically significant increase in the RR of graft failure and patient death for both HCV(+) and HCV(-) recipients. However, HCV(+) recipients demonstrated a significantly higher increase in the RR of patient and graft loss as a function of the DRI than HCV(-) subjects, even after adjustments for several recipient factors, including MELD. In conclusion, a synergistic interaction between donor DRI and recipient HCV status exists, such that an allograft from a high-DRI donor more adversely affects the outcome of an HCV(+) recipient than that of an HCV(-) recipient.

[Treatment with pegylated interferon and ribavirin in a patient with fibrosing cholestatic hepatitis due to recurrent hepatitis C after liver transplantation]

Fibrosing cholestatic hepatitis (FCH) is the most devastating manifestation of recurrent hepatitis C in transplant recipients with hepatitis C virus (HCV), possibly leading to death or retransplantation. Although FCH was first described as a complication of hepatitis B, this manifestation has been well documented in association with HCV in the setting of liver transplantation, bone marrow transplantation, heart transplantation, and end-stage human immunodeficiency virus infection. We report the clinical course and antiviral response in a patient with FCH due to recurrent hepatitis C after cadaveric liver transplantation who was treated with pegylated interferon alpha-2a and ribavirin.

Bioconjugation of oligonucleotides for treating liver fibrosis

Liver fibrosis results from chronic liver injury due to hepatitis B and C, excessive alcohol ingestion, and metal ion overload. Fibrosis culminates in cirrhosis and results in liver failure. Therefore, a potent antifibrotic therapy is urgently needed to reverse scarring and eliminate progression to cirrhosis. Although activated hepatic stellate cells (HSCs) remain the principle cell type responsible for liver fibrosis, perivascular fibroblasts of portal and central veins as well as periductular fibroblasts are other sources of fibrogenic cells. This review will critically discuss various treatment strategies for liver fibrosis, including prevention of liver injury, reduction of inflammation, inhibition of HSC activation, degradation of scar matrix, and inhibition of aberrant collagen synthesis. Oligonucleotides (ODNs) are short, single-stranded nucleic acids, which disrupt expression of target protein by binding to complementary mRNA or forming triplex with genomic DNA. Triplex forming oligonucleotides (TFOs) provide an attractive strategy for treating liver fibrosis. A series of TFOs have been developed for inhibiting the transcription of alpha1(I) collagen gene, which opens a new area for antifibrotic drugs. There will be in-depth discussion on the use of TFOs and how different bioconjugation strategies can be utilized for their site-specific delivery to HSCs or hepatocytes for enhanced antifibrotic activities. Various insights developed in individual strategy and the need for multipronged approaches will also be discussed.