Treatment of chronic hepatitis C in patients with end-stage renal disease and hemophilia--the Singapore experience

Time for Action on Viral Hepatitis

The recent outbreak of hepatitis C virus (HCV) at Singapore General Hospital (SGH) has highlighted the dangers of viral hepatitis. In this case, infection control and environmental contamination were the culprits, particularly, a drop of blood containing 5 million IU HCV. From a broader perspective, there has been a revolution in HCV therapy with the recent rapid evolution of short-term (12 weeks) safe, all oral directly-acting antiviral (DAA) therapy leading to cure rates of 90% to 100%, even in previously difficult to treat patients with liver cirrhosis, previous treatment failure and those on immunosuppression. Consequently, treating HCV in risk groups such as renal dialysis and haemophiliacs can eliminate a pool of infected patients to prevent future outbreaks. A seroprevalence study is needed to identify a possible “birth cohort” effect that could aid screening. For HBV, vaccination has reduced prevalence to 3.8%, but these patients are prone to complications such as HBV flares. Since 2014, 13 patients developed liver failure and were listed for liver transplantation at National University Hospital (NUH) but 6 died beforehand. This avoidable catastrophe is due to undiagnosed HBV infection or patients who did not return for follow-up. Good antiviral therapy is available, but the issues are similar to HCV, identification of patients and linkage to care. A cure seems likely in the future as pharmaceutical companies are developing new agents. Singapore has joined in this initiative with a recent award of a national research translational grant to better understand the pathophysiology and the processes needed for a cure of HBV. Key words: Eradication, Hepatitis C, Linkage to care, Outbreaks, Screening, Treatment

Hepatitis C virus infection and dialysis: 2012 update

Hepatitis C virus infection is still common among dialysis patients, but the natural history of HCV in this group is not completely understood. Recent evidence has been accumulated showing that anti-HCV positive serologic status is significantly associated with lower survival in dialysis population; an increased risk of liver and cardiovascular disease-related mortality compared with anti-HCV negative subjects has been found. According to a novel meta-analysis (fourteen studies including 145,608 unique patients), the adjusted RR for liver disease-related death and cardiovascular mortality was 3.82 (95% CI, 1.92; 7.61) and 1.26 (95% CI, 1.10; 1.45), respectively. It has been suggested that the decision to treat HCV in patients with chronic kidney disease be based on the potential benefits and risks of therapy, including life expectancy, candidacy for kidney transplant, and co-morbidities. According to recent guidelines, the antiviral treatment of choice in HCV-infected patients on dialysis is mono-therapy but fresh data suggest the use of modern antiviral approaches (i.e., pegylated interferon plus ribavirin). The summary estimate for sustained viral response and drop-out rate was 56% (95% CI, 28-84) and 25% (95% CI, 10-40) in a pooled analysis including 151 dialysis patients on combination antiviral therapy (conventional or pegylated interferon plus ribavirin).

HCV in patients with end-stage renal disease

Chronic hepatitis C virus (HCV) infection remains an important cause of liver disease in patients with end-stage renal disease (ESRD) and conversely, renal failure has a significant impact on morbidity and mortality throughout the natural history of chronic HCV and its treatment. With improved awareness within dialysis units of the potential for spread and the institution of preventative measures, the prevalence of HCV infection in the hemodialysis-dependent population has continued to decline since 1995. Use of HCV (+) donor kidneys is associated with an increase in the prevalence of liver disease, but when compared with continued hemodialysis, transplantation using these kidneys is associated with improved survival. Overall, survival in patients with chronic HCV infection appears to be better after renal transplantation when compared with maintenance hemodialysis, and transplant should be considered for these patients. Data support the use of interferon and the improved efficacy of pegylated interferon formulations for treatment of chronic HCV infection in ESRD patients, although tolerability continues to be troublesome. The newest and most promising data regarding the treatment of HCV in ESRD involve the combination of reduced dose ribavirin with interferon or pegylated interferon suggesting similar enhancements in sustained virologic response (SVR) as seen in non-ESRD patients, but caution is advised, as all studies to date used ribavirin plasma concentration monitoring in patient with ESRD. Finally, with regard to postrenal transplant treatment of HCV infection, there is no evidence to support treatment with interferon-based therapy and pretransplant treatment remains the best option whenever possible.

Interferon monotherapy of chronic hepatitis C in dialysis patients: meta-analysis of clinical trials

The efficacy of monotherapy with interferon (IFN) (conventional or pegylated IFN) in dialysis patients with chronic hepatitis C remains unclear, although a number of clinical trials have been published addressing this issue. The aim of the study was to evaluate the efficacy and safety of monotherapy by conventional or pegylated IFN in dialysis patients with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome was sustained virological response (SVR; as a measure of efficacy), and the secondary outcome was drop-out rate (as a measure of tolerability). We used the random-effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses. We identified 28 clinical trials (645 unique patients), of which six (21.4%) had a controlled design. In the group of trials based on conventional IFN, the summary estimate for SVR and drop-out rate was 39% [95% confidence interval (CI) 32-46] and 19% (95% CI 13-26) respectively. The summary estimate for SVR rate in patients with the hepatitis C virus genotype 1 was 33% (95% CI 19-47). In the subset of trials using pegylated IFN, the summary estimate for SVR and drop-out rate was 31% (95% CI 7-55) and 27% (95% CI 1-52) respectively. The most frequent side-effects requiring interruption of treatment were flu-like symptoms, and gastrointestinal and haematological changes. A relationship between age and drop-out rate was found, even if no statistical significance was reached (P = 0.064). The studies were heterogeneous with regard to SVR and drop-out rate. No publication bias was observed. One-third of dialysis patients with chronic hepatitis C were successfully treated with conventional or pegylated IFN monotherapy. Preliminary evidence does not support additional benefit due to monotherapy with pegylated IFN on the viral response in the chronic kidney disease (CKD) population. Tolerance to IFN monotherapy was unsatisfactory, particularly to pegylated IFN. The optimal antiviral treatment of chronic hepatitis C in dialysis populations is currently under active investigation.

Treatment of chronic hepatitis C in patients with haemophilia: a review of the literature

Chronic hepatitis C is a major cause of morbidity and mortality in haemophilia patients. In contrast to studies in the general population, the studies of antiviral therapy in haemophilia patients are limited and often include small numbers of patients. A review of the literature was performed to assess the efficacy of interferon (IFN)-based therapy for patients with haemophilia chronically infected with hepatitis C virus (HCV). Studies were identified by electronic searches (Medline, Embase) and hand searches in references of key articles. Data of the included studies were pooled, and responses to therapy were stratified according to treatment regimen, HIV co-infection status, and treatment history. The main outcome was a sustained virological response (SVR) defined as absence of HCV RNA both at the end of treatment and 24-week post-treatment. Thirty-five studies were identified that included 1151 patients. After pooling the data of included patients, the SVR in HIV-negative treatment naïve patients was 22% for IFN monotherapy, 43% for IFN and ribavirin, and 57% for pegylated IFN and ribavirin, respectively. Re-treatment with IFN and ribavirin of those who failed to respond to previous IFN monotherapy was successful in 33%. In HCV/HIV-coinfected patients, response to IFN monotherapy was 8% and to IFN combined with ribavirin 39%. Responses to IFN-based therapy in patients with haemophilia have been improved over time and are nowadays approximately 50-60%. However, data on haemophilic HCV/HIV-coinfected patients and in patients who failed to respond to previous therapy are limited and future studies in these specific patient population are necessary.