Efficacy of lamivudine for the treatment of hepatitis B virus infection after liver transplantation in children

Updates in the management of hepatitis B in children

Introduction: Universal infant hepatitis B virus (HBV) vaccination program has reduced HBV infection dramatically in vaccinated young generations. Management of chronically infected children is still challenging concerning high viral load with mostly mild diseases, yet with a nonnegligible proportion of advanced diseases, and long-term effect of antivirals. However, with more potent antivirals approved for pediatric patients, to start antivirals earlier in eligible patients may benefit their outcomes. This review aimed to update the current management of chronic hepatitis B in children.Areas covered: This review covered the natural history of chronic HBV infection, management of chronic hepatitis B in children from the past to the present, current consensus on the treatment of chronic hepatitis B in children, controversies in cessation of oral antivirals, and management of special populations such as pregnancy and co-infections.Expert opinions: Without contraindication, peginterferon is recommended for immune-active children ≥ 3 years old. For those intolerant, decompensating or preferring oral therapy, first-line Nucleos(t)ide analogs (NUC), Entecavir or Tenofovir, may be applied. For immune-tolerant or inactive carriers, close monitoring is crucial. When to stop NUCs and novel therapies for HBV cure await further research.

Hepatitis B reactivation in allogeneic hemopoietic stem cell transplantation setting: a pediatric experience

Reactivation of HBV is a well known complication in patients undergoing HSCT. Lamivudine treatment appears to prevent hepatitis B virus reactivation and to decrease the mortality in at risk HSCT patients. We describe HBV reactivation occurred in three allogeneic HSCT pediatric patients coming from Eastern Europe, one of whom was successfully treated with lamivudine. Our experience confirms that HBV-DNA may persist as intra-hepatic infection or in extra-hepatic sites and that HBV reactivation may appear during immunodepression. Careful and complete screening for HBV markers is mandatory before HSCT, especially in children coming from countries at risk for HBV. Furthermore, a treatment with lamivudine could also represent an efficacious prophylaxis in pediatric patients to avoid HBV reactivation and to decrease the development of severe hepatic disease.

Treatment of Viral Hepatitis in Children

Hepatitis B and hepatitis C are important causes of chronic liver disease in children and adolescents, and later on for potential cirrhosis and primary hepatocellular carcinoma. The risk of developing chronic hepatitis B (HB) infection ranges from 90% in neonates to <5% in adults. Hepatitis C induces chronic infection in at least 85% of affected persons. HBV and HCV associated liver damage appears to be less severe in children than in adults. At the present time, lamivudine and a combination of interferon and lamivudine seem to be the best options for HB infection treatment in the pediatric population, even though they induce the presence of drug-resistant mutations, and new therapies have to be developed to improve reduction and cessation of viral replication and decrease the emergence of mutations. Therapy with interferon and ribavirin seems to offer the best results for children and adolescents. Results from a study on pegylated interferon in a pediatric population might lead to better therapeutic responses. Cost of treatment for chronic viral hepatitis is very high and efforts have to continue to extend hepatitis B vaccination to the general population worldwide to reduce vertical and horizontal transmission of hepatitis C.

Nucleoside analogues and other antivirals for treatment of hepatitis B in the peritransplant period

Chronic HBV infection is a common cause of advanced liver disease that is associated with substantial mortality. Furthermore, chronic hepatitis B was historically a controversial indication for liver transplantation because of a low post-transplant survival, with graft infection being the major contributor to adverse outcomes. The initial use of hepatitis B immune globulin as prophylaxis, followed later by combined therapy with lamivudine, markedly reduced viral recurrence and improved the survival of patients transplanted for acute or chronic hepatitis B with liver failure. Lamivudine alone can also be used for long-term prophylaxis against de novo HBV infection that can be transmitted by organs from donors positive for anti-HBc or anti-HBs. When used in patients with decompensated chronic hepatitis B with cirrhosis, lamivudine has been shown to improve clinical manifestations, prolong pretransplant survival, and defer, or even obviate, the need for transplantation. Despite prophylaxis, viral mutations with breakthrough reinfection may occur and lead to liver failure. The recently approved adefovir dipivoxil, which is active against lamivudine-resistant mutation, and other nucleoside analogs that are in various phases of development, offer hope as rescue therapy for viral recurrence. Other therapeutic alternatives in the future may include gene therapy and immune interventions.

Pediatric issues in new therapies for hepatitis B and C

Two antiviral treatments have been approved for hepatitis B virus (HBV) infection by the US Food and Drug Administration (FDA) for use in children: interferon (IFN)-alpha, 6 MU/m(2) three times a week subcutaneously for 6 months, and lamivudine, 3 mg/kg/d orally for 12 months. Twenty-six percent to 58% of children treated with IFN become HBV DNA negative, and up to 38% become negative to hepatitis B e antigen (HBeAg). Lamivudine, a nucleoside analogue that blocks viral replication by inhibition of the HBV polymerase, has been associated with comparable rates of seroconversion of HBeAg to anti-HBe. Loss of surface antigen occurs in less than 5% of patients treated with lamivudine, compared with 3% to 33% in those treated with IFN-alpha. Fifty percent to 65% of children treated with lamivudine clear HBV DNA after 12 months of therapy, but relapse rates have not been clarified. Patients treated with lamivudine develop drug-resistant (YMDD) mutants in the HBV polymerase at the rate of 16% to 32% per year. No treatments for children with hepatitis C virus (HCV) have been approved by the FDA. However, published reports describe treatment with IFN monotherapy and combination therapy with IFN and ribavirin. Trials of PEG-IFN alone or in combination with ribavirin are in progress. Given the lack of data regarding treatment of HCV in children, it is generally agreed among pediatric hepatologists that the optimal treatment is within the context of randomized, controlled trials.

Treatment of recurrent hepatitis B infection in liver transplant recipients

1. Therapeutic decisions are guided by a patient's clinical status (severity of disease and presence of comorbidities) and previous drug-exposure history. 2. Lamivudine is safe and effective in liver transplant recipients with recurrent hepatitis B virus (HBV) infection caused by wild-type virus or failure of hepatitis B immunoglobulin therapy. Lamivudine resistance, developing in approximately 25% after 12 months of therapy, is its main limitation. 3. Famciclovir is safe in liver transplant recipients; however, virological and clinical responses are less consistent than with lamivudine. Thus, lamivudine is favored over famciclovir as first-line therapy in transplant recipients with no previous exposure to nucleoside analogues. 4. Although limited in availability, adefovir dipivoxil appears safe and effective in treating liver transplant recipients with lamivudine-resistant HBV disease. Close monitoring of renal function is recommended, with dose adjustment in patients with reduced creatinine clearances. 5. Limited data suggest that intravenous ganciclovir, tenofovir disoproxil fumarate, and interferon alfa may be useful as rescue therapies for patients with lamivudine- or famciclovir-resistant HBV disease. 6. Antiviral therapy with two or more suitable agents may minimize the chance for viral resistance; therefore, future therapeutic strategies likely will use combination therapy in the long-term management of recurrent HBV disease.

Seroconversion after the addition of famciclovir therapy in a child with hepatitis B virus infection after liver transplantation who developed lamivudine resistance

There is very little information about hepatitis B virus (HBV) infection in children after liver transplantation. This is the first report of the addition of famciclovir in a child who developed lamivudine resistance.A 5-year-old boy who was serum HBsAg-negative and was not vaccinated against HBV underwent living-related liver transplantation for fulminant hepatitis A. The donor was his mother, who was serum HBcAb-positive. No immunoprophylaxis was administered. HBV infection developed after 18 months and was treated with 3 mg/kg daily of lamivudine. Serum alanine aminotransferase normalized and HBV DNA load decreased significantly. Sixteen months later, lamivudine resistance developed; a mutation (M552I) was confirmed by sequencing through the YMDD locus of the HBV polymerase gene. The addition of 750 mg daily of famciclovir led to seroconversion and the disappearance of serum HBV DNA. Lamivudine in combination with famciclovir might be a therapeutic option for HBV reinfection after liver transplantation, also in children. Suppression of viral replication to undetectable values is possible even in the lamivudine-resistant mutant.

Lamivudine for the treatment of chronic hepatitis B

Lamivudine (Zeffix, Epivir, GlaxoSmithKline) is the most important recent advance in the treatment of chronic hepatitis B in both adults and children. It is the only available oral treatment and has an excellent safety profile, which makes it even more attractive. It increases the rate of hepatitis B e antigen (HBeAg) loss and seroconversion in compensated chronic HBeAg-positive carriers, with subsequent improvement of histology at a similar rate as IFN-alpha. Lamivudine is mostly active in patients with elevated transaminases and is not effective in compensated patients with quiescent disease. Long-term follow-up studies are still required to evaluate long-term benefits, including those on hepatitis B surface antigen (HBsAg) seroconversion rate and disease evolution control. In decompensated patients, the drug can stabilise and improve liver function, allowing the patient to wait safely for transplantation. Patients may improve to such an extent that transplantation can be postponed. Combined with hepatitis B immunoglobulin (HBIG), lamivudine considerably decreases the risk of graft re-infection after transplantation. It is also active in chronic HBeAg-negative hepatitis patients, for whom IFN is less efficient. The major drawback is the emergence of the tyrosine-methionine-aspartate-aspartate (YMDD) mutation, which prevents further efficacy of the drug and may lead to flares of hepatitis. Due to the questions the YMDD mutation raises and because hepatitis B is a complex disease, indications for treatment must be established with care and only by physicians with expert knowledge of the disease, the drug and YMDD mutation-related issues.