Neonatal and pediatric posttransfusion hepatitis C: a look back and a look forward

Use of an integrated modelling and simulation approach to develop a simplified peginterferon alfa-2a dosing regimen for children with hepatitis C

AIM

The aim of the study was to simplify the dosing regimen of peginterferon alfa-2a in paediatric patients with chronic hepatitis C.

METHODS

A population pharmacokinetic (PK) model was developed using PK data from 14 children aged 2-8 years and 402 adults. Simulations were produced to identify a simplified dosing regimen that would provide exposures similar to those observed in the paediatric clinical trials and in the range known to be safe/efficacious in adults. Model predictions were evaluated against observed adult and paediatric data to reinforce confidence of the proposed dosing regimen.

RESULTS

The final model was a two compartment model with a zero order resorption process. Covariates included a linear influence of body surface area (BSA) on apparent oral clearance (CL/F) and a linear influence of body weight on apparent volume of distribution of the central compartment (V1 /F). A simplified dosing regimen was developed which is expected to provide exposures in children aged ≥5 years similar to the dosing formula used in the paediatric clinical trial and within the range that is safe/efficacious in adults. This simplified regimen is approved in the EU and in other countries for the treatment of chronic hepatitis C in treatment-naive children/adolescents aged ≥5 years in combination with ribavirin.

CONCLUSION

Pre-existing adult PK data were combined with relatively limited paediatric PK data to develop a PK model able to predict exposure in both populations adequately. This provided increased confidence in characterizing PK in children and helped in the development of a simplified dosing regimen of peginterferon alfa-2a in paediatric patients.

The epidemiology of transfusion-associated hepatitis C in a children's hospital

BACKGROUND

Children transfused with blood and blood products before 1992 are at risk for chronic hepatitis C virus (HCV) infection. To determine the prevalence of HCV infection and risks associated with acquisition of HCV, a single-institution lookback study was performed.

STUDY DESIGN AND METHODS

A total of 5473 infants and children who received transfusions between 1982 and 1992 were identified. A control population of 600 age-, sex-, race- and zip code-matched children who did not receive transfusions with the same exclusions provided background seroprevalence data. Patients were tested for antibodies to HCV, confirmed with second generation recombinant immunoblot assay (RIBA) and when appropriate quantitative and qualitative HCV RNA by reverse transcription polymerase chain reaction (PCR). Viral persistence was assessed by serial PCR determinations for HCV RNA.

RESULTS

Of the 5473 eligible patients, 4726 were locatable and 2758 were tested. Forty-three children (1.6%) were persistently anti-HCV enzyme immunoassay (EIA)-positive, confirmed by RIBA; 39 were positive for the presence of HCV RNA. Four cleared their virus as assessed by two negative HCV PCRs 6 months apart. There was a borderline higher number of children with HCV who received fresh whole blood than those who tested HCV-negative.

CONCLUSION

Because HCV infection is generally asymptomatic, children are not identified unless they are specifically tested. We identified, enrolled, tested, and confirmed a new diagnosis of HCV infection in 43 patients. As HCV treatments become increasingly effective, it is important to identify silently infected individuals, particularly when the infection was iatrogenically induced.

Look-back study of Hepatitis C in teenagers after blood transfusions as neonates

AIM

To conduct a single-centre "look-back" study of the prevalence of hepatitis C in teenagers who had received blood products as newborns, prior to hepatitis C virus (HCV) blood donor screening.

METHODS

Using blood bank records, we identified 732 surviving teenagers aged 14-18 years who had received blood products as neonates during 1986-1990. Letters recommending HCV antibody testing were sent to 732 surviving teenagers; 581 recipients were contacted and invited to undergo testing, and, of these, 429 consented (59% of the survivors). HCV antibody testing was performed on all and HCV-RNA was tested on those who were antibody positive.

RESULTS

Three teenagers (0.7%, 95% CI 0.54-0.86) tested positive for HCV antibodies and all three were HCV-RNA positive. There were no cases in which antibodies were detected and polymerase chain reaction (PCR) was negative. Two of the three had mildly elevated liver enzymes and all three had mild inflammatory activity and low fibrosis scores on liver biopsy.

CONCLUSIONS

The look-back process, even in a single centre with a stable urban population, is relatively inefficient in screening at-risk populations. Although the prevalence of hepatitis C in this sample was relatively low, paediatricians should offer screening to teenagers and young adults who received blood products in the neonatal period.

Clinical spectrum and histopathologic features of chronic hepatitis C infection in children

OBJECTIVE

To define the natural history and outcomes of children infected with hepatitis C virus (HCV) at birth or in early childhood.

STUDY DESIGN

This retrospective, prospective study identified 60 HCV-infected children through a transfusion look-back program (group 1) and by referrals (group 2). Perinatal/transfusion history, clinical course, and laboratory studies were correlated with findings from 42 liver biopsy specimens.

RESULTS

Mean age at infection was 7.1 months, and duration of infection 13.4 years. The sources of infection were blood transfusion (68%), perinatal transmission (13%), and both (7%). Most patients were asymptomatic; three referral patients had advanced liver disease at presentation. Mean alanine aminotransferase level was normal in 25%, 1 to 3 times normal in 62%, and greater than 3 times normal in 13%. Liver biopsy specimens showed minimal to mild inflammation in 71%, absent or minimal fibrosis in 88%, and bridging fibrosis in 12%. Age at infection and serum gamma-glutamyltranspeptidase correlated with fibrosis; serum alanine aminotransferase correlated with inflammation unless complicated by comorbidity. Repeat biopsies within 1 to 4 years in four patients showed no significant progression in three and cirrhosis in one. Two patients died after liver transplantation.

CONCLUSIONS

Children with chronic HCV infection are generally asymptomatic. By 13 years after infection, 12% of patients had significant fibrosis. Patients enrolled by referral had more severe liver disease than those identified through the look-back program, demonstrating the importance of selection bias in assessing the long-term outcome of HCV infection.

Routine hepatitis C virus screening in pregnancy: a cost-effectiveness analysis

OBJECTIVE

The purpose of this study was to determine whether routine hepatitis C virus screening in pregnancy is cost-effective.

STUDY DESIGN

A decision tree with Markov analysis was developed to compare 3 approaches to asymptomatic hepatitis C virus infection in low-risk pregnant women: (1) no hepatitis C virus screening, (2) hepatitis C virus screening and subsequent treatment for progressive disease, and (3) hepatitis C virus screening, subsequent treatment for progressive disease, and elective cesarean delivery to avert perinatal transmission. Lifetime costs and quality-adjusted life years were evaluated for mother and child.

RESULTS

In our base case, hepatitis C virus screening and subsequent treatment of progressive disease was dominated (more costly and less effective) by no screening, with an incremental cost of 108 US dollars and a decreased incremental effectiveness of 0.00011 quality-adjusted life years. When compared with no screening, the marginal cost and effectiveness of screening, treatment, and cesarean delivery was 117 US dollars and 0.00010 quality-adjusted life years, respectively, which yields a cost-effectiveness ratio of 1,170,000 US dollars per quality-adjusted life year.

CONCLUSION

The screening of asymptomatic pregnant women for hepatitis C virus infection is not cost-effective.

Treatment options for hepatitis C infection in children

Multiple factors support treatment of hepatitis C virus (HCV) infection in children. These factors include the anticipated long duration of infection after early acquisition, relatively good tolerance of antiviral medications, and avoidance of social stigmatization. Nevertheless, careful selection of appropriate candidates for therapy is important. If a contraindication to current therapeutic agents is present, treatment should be withheld until this has resolved or until new agents are available. Children without contraindications to the medications used for HCV should undergo liver biopsy to determine the presence and degree of fibrosis. In the absence of fibrosis, treatment may be deferred. If any degree of hepatic fibrosis is present, antiviral therapy for HCV should be considered. At present, in the United States, the only therapy approved for children by the Food and Drug Administration (FDA) is a combination of interferon (IFN) alfa-2b and ribavirin. No safe therapies have been established for children younger than 3 years of age. Pegylated interferon in combination with ribavirin may be considered in adolescents older than 16 years of age who are post-pubertal, or in younger children in the context of clinical trials. Multicenter trials are currently underway to determine the safety and effectiveness of other forms of therapy for HCV infection in children.

Molecular epidemiology of hepatitis B and C virus infections in Asia

The present paper provides a review of the current literature regarding the molecular-based epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV), which are very important viruses underlying the etiology of blood-borne infectious diseases worldwide. Particularly, both HBV and HCV are widespread on the Asian continent and are associated with acute and chronic liver diseases, including hepatocellular carcinoma. HBV has been classified into genotypes A through G and shown to have a distinct geographic distribution. In Asia, genotypes B and C of HBV prevail, and genotype C has been shown to cause more serious liver disease than genotype B. High prevalence of HBV mutants with various forms, such as the pre-S mutant, basal core promoter mutant, YMDD motif mutant and vaccine escape mutant, were seen in Asia and these were found to be related to the severity of liver disease and sensitivity to therapy. HCV has also been classified into multiple genotypes and associated with geographic distribution. HCV genotype 1 is less sensitive to interferon therapy and may be associated with the presence of more serious liver disease than the other genotypes. Data on the relation among the HBV/HCV genotypes, their pathogenicity in chronic liver diseases including hepatocellular carcinoma and their effect on therapy are awaited with great interest, especially in Asia, which is an endemic region of blood-borne hepatitis viruses.

Combination therapy with ribavirin and interferon in a cohort of children with hepatitis C and haemophilia followed at a pediatric haemophilia treatment center

Nearly all children with bleeding disorders who received factor concentrates prior to the late 1980s were infected with hepatitis C. Treatment of adults infected with hepatitis C with combination therapy consisting of ribavirin and interferon has shown sustained response rates of 30-60%. Little data is available on the response of children infected with hepatitis C treated with combination therapy, especially those with bleeding disorders. We wish to report a single paediatric haemophilia treatment center's results of treatment of adolescents with haemophilia and hepatitis C infection with combination therapy. All patients followed at the haemophilia treatment center with hepatitis C, who were human immunodeficiency virus (HIV) negative and had a measurable hepatitis C viral load were eligible. Study patients received at least 6 months of 3 MU interferon-alpha via subcutaneous injection three times per week and 1000 mg day(-1) of ribavirin. Eleven patients agreed to participate in the study. Three patients had an un measurable viral load after 6 months of combination therapy. All three completed 12 months of medication and continued to remain free of hepatitis C for 12 months after discontinuation of therapy. Side-effects of combination therapy were significant but tolerable. The sustained response rate in this study is similar to the historical response rate seen in adults but less than the other reported response rates seen in children treated with combination therapy. Given the toxicity of combination therapy, and natural history of hepatitis C infection in children, consideration of a liver biopsy to evaluate disease progression prior to considering antiviral medications is warranted.

The effect of early treatment in children with chronic hepatitis

BACKGROUND

The aim of this study was to compare the efficacy of interferon alpha (IFN) or IFN and ribavirin (IFN+RIB) combination therapy in children with chronic hepatitis C (CHC). Most children were infected during treatment for pediatric malignancies.

PATIENTS AND METHODS

We reviewed the charts of 20 patients (11 boys and 9 girls) aged 10.6 +/- 3.7 years with CHC who were treated between 1995 and 2001. Seven patients diagnosed with CHC before 1998 were treated with 3 million units of IFN three times weekly for 6 to 12 months. Thirteen children diagnosed after 1998 were treated with 3 million units of IFN three times weekly plus 15 mg/kg of ribavirin daily for 6 months (IFN+RIB).

RESULTS

Demographic and clinical characteristics were not different between the two treatment groups. A sustained complete response defined as serum alanine aminotransferase normalization and hepatitis C virus RNA clearance at 6 and 12 months after termination of treatment occurred in three of seven children (43%) treated with IFN monotherapy compared with 7 of 12 children (54%) in the group treated with IFN+RIB combination therapy (not significant). The only difference between responders and nonresponders was the duration of infection before the initiation of therapy, which was significantly shorter in responders (1 +/- 0.3 vs. 5.6 +/- 2.2; P = 0.001).

CONCLUSIONS

In this small cohort of children with CHC, early initiation of antiviral treatment was associated with a sustained response rate independent of treatment type. Regular follow-up of children at risk of acquiring hepatitis C virus infection should assist in the early diagnosis. Early initiation of antiviral treatment may improve the rate of sustained response.

[Role of interferons in the treatment of hepatitis B and hepatitis C virus infections]

BACKGROUND

Since the discovery of hepatitis C (HCV), the efficacy of treatment has significantly progressed using standard mono-therapy: with Interferon alpha (IFN) during six months we obtained approximately 10% sustained response and currently with the association of pegylated IFN and Ribavirin a 55% sustained response was achieved.

CURRENT POSITION AND MAJOR POINTS

HCV infection continues to present therapeutic problems which have not entirely been solved, mainly related to clinical and biological tolerance, and non-responders. Moreover, the care of patients with extra-hepatic localization, cirrhotic patients, as well as therapeutic problems of co-infected HIV-HCV patients. As regards hepatitis B (HBV) new effective treatments against this virus have appeared, IFN then nucleoside analogs, some of which are available in France (i.e. lamivudine, adefovir, dipovoxil). The main objective of chronic hepatitis B treatment is to obtain the complete inhibition of the HBV virus by Hbe-antigen antibody seroconversion which would therefore significantly increase patient survival. In this article the advantages and disadvantages of the different treatments are assessed.

FUTURE PERSPECTIVES

Despite the considerable and rapid progress obtained in the therapeutic treatment of infection due to HCV and HBV a number of unknown factors remain, which warrants further trials, in particular to evaluate the efficacy as well as the tolerance of the antiviral agent association.

Hepatitis C in childhood

The approach of a pediatric hepatologist in managing children with hepatitis C virus (HCV) differs from adult practice, because the pediatric hepatologist is dealing with the beginning of a chronic illness in which long-term outcomes will not occur for 20 or 40 years, and it is not possible to predict in the early stages of the infection which patients have a more sinister prognosis. The prevalence of chronic HCV in children is low, but varies between different countries in the Asia-Pacific region. In most countries, screening of blood products for HCV has virtually eliminated the risk of post-transfusion HCV, so that in Australia children aged less than 11 years will not have acquired HCV from blood transfusion or extracorporeal membrane oxygenation. The risk of perinatal transmission of this virus is only about 6%, but this remains virtually the only source of HCV transmission for children in most countries. While available data are limited, mild histological changes are present in the majority of children with hepatitis C, and cirrhosis is rare. Unfortunately, long-term natural history studies of the course of HCV infection in children have not been reported. Individual decisions on antiviral treatment are more difficult in childhood, not because the treatment is any less effective or because of the severity of side-effects (which tend to be less severe than for adults), but because the long-term outcome of infection is unclear. At present, treatment should be confined to those with significant hepatic fibrosis and continued moderate to severe necroinflammatory change. Measures to prevent HCV infection in childhood center on whether, as recently suggested, elective cesarean section may reduce the risk of transmission. Despite the presence of HCV-RNA in some breast milk samples, there is no evidence that breast-feeding confers any risk of HCV infection.