Management of hepatitis C-infected liver transplant recipients at large North American centres: changes in recent years

Drug Interactions With Direct-Acting Antivirals for Hepatitis C: Implications for HIV and Transplant Patients

OBJECTIVE

Review pharmacokinetics of new direct-acting antivirals (DAAs) for hepatitis C (HCV) infection and interactions with concomitant immunosuppressant and antiretroviral therapies (ART).

DATA SOURCES

MEDLINE (1948-January 2015), EMBASE (1964-January 2015), International Pharmaceutical Abstracts (1970-January 2015), Google, and Google Scholar were searched combining the terms simeprevir, sofosbuvir, ledipasvir, daclatasvir, paritaprevir, ABT-450, ombitasvir, dasabuvir, pharmacokinetics, drug interaction, drug metabolism, HIV, antiretroviral, immunosuppressant, transplant. Articles, conference proceedings, abstracts, and product monographs were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Literature on pharmacokinetic or pharmacodynamic interactions with DAAs and immunosuppressants or ART was considered for inclusion. Pertinent information was extracted and summarized in the review. In the absence of data, pharmacokinetic and pharmacodynamic principles were used to predict the likelihood of interactions.

DATA SYNTHESIS

DAA pharmacokinetics are reviewed and drug interaction data are presented with provision of management strategies. Fixed-dose combination paritaprevir/ritonavir/ombitasvir plus dasabuvir is most susceptible to drug interactions with immunosuppressants and ART mainly due to the influence of ritonavir on multiple enzymes. Simeprevir is also prone to drug interactions because of cytochrome P450(CYP) 3A4, CYP1A2, P-glycoprotein, and OATP1 involvement and is not recommended for use in combination with several HIV antiretrovirals (ARVs). Close therapeutic drug monitoring of calcineurin inhibitors is required with concomitant simeprevir. Few clinically significant interactions are expected with sofosbuvir or ledipasvir. Limited data suggest that daclatasvir may be coadministered with immunosuppressants but requires dose adjustments with certain ARVs.

CONCLUSIONS

None of the DAAs are completely free of drug interactions. Awareness and management of drug interactions is critical to optimize outcomes and minimize adverse effects in these patient populations.

Mortality among British Columbians testing for hepatitis C antibody

BACKGROUND

Hepatitis C virus (HCV) infection is a major preventable and treatable cause of morbidity and mortality. The ability to link population based centralized laboratory HCV testing data with administrative databases provided a unique opportunity to compare mortality between HCV seronegative and seropositive individuals. Through the use of laboratory testing patterns and results, the objective of this study was to differentiate the viral effects of mortality due to HCV infection from risk behaviours/activities that are associated with acquisition of HCV infection.

METHODS

Serological testing data from the British Columbia (BC) Centre for Disease Control Public Health Microbiology and Reference Laboratory from 1992-2004 were linked to the BC Vital Statistics Agency death registry. Four groups of HCV testers were defined by their HCV antibody (anti-HCV) testing patterns: single non-reactive (SNR); serial multiple tested non-reactive (MNR); reactive at initial testing (REAC); and seroconverter (SERO) (previously seronegative followed by reactive, a marker for incident infection). Standardized mortality ratios (SMRs) were calculated to compare the relative risk of all cause and disease specific mortality to that of the BC population for each serological group. Time dependent Cox proportional hazard regression was used to compare hazard ratios (HRs) among HCV serological groups.

RESULTS

All anti-HCV testers had higher SMRs than the BC population. Referent to the SNR group, the REAC group had higher risks for liver (HR: 9.62; 95% CI=8.55-10.87) and drug related mortality (HR: 13.70; 95% CI=11.76-16.13). Compared to the REAC group, the SERO group had a lower risk for liver (HR: 0.53; 95% CI=0.24-0.99), but a higher risk for drug related mortality (HR: 1.54; 95% CI=1.12-2.05).

CONCLUSIONS

These findings confirm that individuals who test anti-HCV positive have increased mortality related to progressive liver disease, and that a substantial proportion of the mortality is attributable to drug use and risk behaviours/activities associated with HCV acquisition. Mortality reduction in HCV infected individuals will require comprehensive prevention programming to reduce the harms due to behaviours/activities which relate to HCV acquisition, as well as HCV treatment to prevent progression of chronic liver disease.

Health utilities and psychometric quality of life in patients with early- and late-stage hepatitis C virus infection

BACKGROUND AND AIM

Hepatitis C virus (HCV) infection is associated with impairment in health-related quality of life (HRQOL). The purpose of this study was to evaluate HRQOL across the HCV disease spectrum using preference-based (utility) and non-preference-based (psychometric) methods, adjusting for sociodemographic factors and co-morbidity.

METHODS

Hepatitis C virus patients (n = 751) were recruited from several tertiary care settings in Vancouver, Canada for this observational, cross-sectional cohort study. Patients completed the Health Utilities Index Mark 2/3, a self-administered time trade-off utility instrument, and the Hepatitis Quality of Life Questionnaire (SF-36 with HCV-specific items). We examined the association between HRQOL and disease stage using linear regression adjusting for age, education, marital status, income, and co-morbidities.

RESULTS

Utility scores were low across disease stage and instrument, ranging from 0.51 to 0.80. On the SF-36, the mean Physical Component Summary score ranged from 37.2 to 49.2 across disease stage, and the Mental Component Summary score ranged from 39.7 to 45.7 (United States norms = 50). In general, patients with viral clearance had the highest scores, and those with late-stage disease (cirrhosis, liver cancer) had the lowest. Multivariable linear regression showed that the effect of disease stage was modest overall. Increasing age, lower income, unattached marital status, and high comorbidity were strongly associated with impairment in HRQOL.

CONCLUSIONS

The effect of stage of disease on HRQOL is modest, although viral clearance is associated with higher HRQOL. HCV patients' HRQOL is strongly associated with concomitant illness and sociodemographic factors.

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

Hepatitis C virus (HCV) infection is the major indication for liver transplantation worldwide. Its recurrence is virtually universal. Once reinfection is established, progression to cirrhosis occurs in 25%-30% of recipients within 5 years. Several studies have attempted to identify the ideal antiviral treatment for liver transplant recipients. At present, the management of recurrent HCV infection in liver transplant recipients is based on widely accepted indications, which represent a reliable guide to identify the "ideal" candidate for therapy, when therapy should be started, and what is to be expected in terms of side effects and response to treatment.

Measurement of CD4+ T-cell function in predicting allograft rejection and recurrent hepatitis C after liver transplantation

Recurrence of hepatitis C virus (HCV) can be difficult to distinguish from acute cellular rejection (ACR) following liver transplantation. The Cylex Immune Function Assay (ImmuKnow) provides objective measure of recipient's immune function. The goal is to assess the ability of this assay to distinguish these similar conditions. A retrospective review was performed in 54 recipients with HCV. ImmuKnow assays were measured with allograft biopsies. Levels of adenosine triphosphate (ATP) release from CD4+ T cells (ng/mL) were compared with the following biopsy result classifications: 365 ± 130 with ACR (n = 11), 152 ± 100 with recurrent HCV (n = 26), 240 ± 71 with normal biopsies (n = 12), and 157 ± 130 with overlapping features of ACR and recurrent HCV (n = 5). Recipients with recurrent HCV had lower immune response than those with ACR (p < 0.0001).Using a cutoff level of 220, the sensitivity and specificity for distinguishing two conditions were 88.5% and 90.9%, respectively. When recipients with overlapping features had low immune response, three of four recipients' subsequent biopsies showed recurrent HCV. In conclusion, the ImmuKnow assay can be a sensitive and specific additional test for distinguishing recurrent HCV from ACR and may be useful for predicting which recipients may be most vulnerable to recurrent HCV.

Recipient-based approach to tailoring immunosuppression in liver transplantation

Improvements in the field of transplant immunosuppression (IS) have led to significant advances in long-term survival of liver transplant recipients. Despite this progress, survival rates vary depending on recipient, donor and/or perioperative factors. Tailoring IS based on recipient factors is of growing interest among health care providers involved in the care of organ transplant recipients. To date there is no consensus document addressing individualized IS therapy for liver transplant recipients. This review will discuss the information available on the effect of the various IS drugs on recipient-based factors such as age, ethnicity, and liver disease etiology.

Should trichrome stain be used on all post-liver transplant biopsies with hepatitis C virus infection to estimate the fibrosis score?

Recurrent hepatitis C is virtually universal after liver transplantation; however, an individual patient's clinical course and disease burden are highly variable and difficult to predict. The fibrosis score determined on posttransplant biopsies appears to be a sensitive and specific marker of disease progression and severity. Currently, the fibrosis score is determined from hematoxylin and eosin (H&E)-stained tissue sections supplemented by variable use of trichrome stain or other connective tissue-specific stains. In this study, we compare the fibrosis score on H&E stain with that obtained with trichrome stain in posttransplant liver biopsies of patients with hepatitis C. A total of 197 liver biopsies from 105 allograft patients with hepatitis C were reviewed. The mean fibrosis stage was 1.0 +/- 1.25 with H&E stain versus 1.69 +/- 1.42 with trichrome stain (P < 0.00001). The trichrome staging score was higher in 53.3%, lower in 3%, and the same in 43.7%. The fibrosis stage was raised by 2 or more points in 17.8% and elevated into a bridging category in 14.7%. No significant differences in clinical and laboratory levels were measured in patients with higher fibrosis scores. In conclusion, the hepatic fibrosis score is significantly underestimated by H&E stain in the posttransplant setting in patients with hepatitis C. The fibrosis stage may be an indicator of significant liver damage in these patients. Accuracy of its determination may be most easily facilitated by employment of a connective tissue stain.

The impact of donor variables on the outcome of orthotopic liver transplantation for hepatitis C

Morphologic characteristics of the graft have been proposed as a major contributor to the long-term outcomes in orthotopic liver transplantation (OLT). Our objective was to determine the impact of donor variables, including donor age, donor-recipient HLA match, and type of donation (DCD vs donation after brain death [DBD]), on the outcome of OLT in 192 patients with hepatitis C virus (HCV). Fourteen patients underwent OLT from donation after cardiac death (DCD) donors and 188 from DBD donors. Mean donor age, warm ischemia time at recovery, and cold ischemia time were similar between the groups. Overall graft survival rate at 1 year (55% DCD vs 85% DBD) and 5 years (46% DCD vs 78% DBD) was significantly lower in the DCD group (P = .0003). Similarly, patient survival rate at 1 year (62% DCD vs 93% DBD) and 5 years (62% DCD vs 82% DBD) was significantly lower in the DCD group (P = .0295). Incidences of hepatic artery thrombosis, portal vein thrombosis, and primary nonfunction were similar between the DCD and DBD groups. The incidence of liver abscess with ischemic-type biliary stricture was higher in recipients from DCD as compared with DBD (42% vs 2%). A trend toward lower graft survival was noted in recipients from donors older than 60 years of age in the HCV population (P = .07), with statistically lower patient survival (P = .02). Donor- recipient HLA matching did not appear to correlate with OLT outcome in patients with HCV. DCD donors and donors older than 60 years of age significantly impact patient and graft survival. Lower graft and patient survival in recipients from DCD donors does not appear to be related to early disease recurrence.

Antifungal management practices in liver transplant recipients

We sought to determine the approach to antifungal prophylaxis, and diagnostic and therapeutic practices for the management of invasive aspergillosis in liver transplant recipients. Data were collected by an electronic survey questionnaire sent to all active liver transplant programs in North America; 63% (67/106) of the sites completed the survey. Overall, 91% of the sites employed antifungal prophylaxis; 28% used universal prophylaxis and 72% targeted it toward high-risk patients. Fluconazole was the most commonly used agent for universal and targeted prophylaxis. The leading choice for mold-active agents for antifungal prophylaxis was the echinocandins. Combination therapy was used as primary therapy for invasive aspergillosis in 47%, and as salvage in 80%. Thus, a vast majority of the surveyed programs employ antifungal prophylaxis and most use targeted prophylaxis. Consideration of these practices could guide clinical trial design to optimize antifungal prophylaxis in these patients. Our findings also merit investigations to better define the role of diagnostic assays and combination therapeutic strategies for invasive aspergillosis in liver transplant recipients.

Therapeutic management of recurrent hepatitis C after liver transplantation

Recurrent hepatitis C ranges from minimal damage to cirrhosis developing in a few months or years in a substantial proportion of transplant recipients. Different virus, host and donor factors are involved in the pathogenesis of recurrence, but many are poorly understood. Therapeutic strategies can be utilized in the pre-, peri- or posttransplantation setting. Antiviral therapy using interferon and ribavirin and modifying immunosuppression are the main strategies to prevent progression disease. The efficacy of interferon and ribavirin is limited and side effects, reduction/withdrawal are frequent. Current sustained virological response rates are approximately 28%. An optimal immunosuppression regimen has not been established. The choice of calcineurin inhibitors has not clearly been shown to affect histological hepatitis C virus (HCV) but higher cumulative exposure to corticosteroids to treat acute rejection is associated with more severe recurrence. The manner in which the doses of immunosuppression are modified has more influence on HCV recurrence than the use of a specific drug per se. Debate about the influence of immunosuppressive regimens on HCV recurrence is ongoing. Potential antifibrotic therapy and new agents targeting HCV infection and replication are emerging and are anticipated to be added to our armentarium in battling recurrent HCV post-LT.

Acute rejection in HCV-infected liver transplant recipients: The great conundrum

1. In hepatitis C virus (HCV)-infected patients, treatment of acute rejection is associated with worse outcomes (increased risk of allograft cirrhosis and mortality). 2. Whether patients with HCV are at higher risk for rejection remains controversial. 3. The mechanisms mediating acute rejection and recurrence of HCV are distinct, and as such, it should be possible to develop techniques based on these molecular differences that are diagnostically useful. 4. Liver biopsy is considered the gold-standard for diagnosing acute rejection and recurrent HCV; however, given histopathological similarities between the two conditions, discrimination can be extremely difficult. 5. At the present time, there are no reliable, noninvasive tools available to distinguish between HCV recurrence alone and acute rejection plus HCV recurrence. 6. Mild rejection per se is not associated with graft loss and treatment of rejection with steroids and OKT3 is associated with worse outcome in HCV; thus, it seems logical that we should no longer treat mild rejection.