Entecavir at Five Years Shows Long-Term Maintenance of High Genetic Barrier to Hepatitis B Virus Resistance

Current clinical evidence for nucleos(t)ide analogues in patients with HBV-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of death globally and is frequently seen following Hepatitis B virus (HBV) or Hepatitis C virus infection. Areas with high HBV infection rates, such as Asia and sub-Saharan Africa, are therefore also high-risk areas for HCC. Areas covered: This review identifies and discusses the current evidence from robust clinical trials which have investigated the benefits of Nucleos(t)ide analogue (NA) antiviral therapy in HBV-related HCC patients, including HCC patients that underwent liver transplantation and HCC patients with or without curative treatment. In addition, we assess how this evidence has influenced current clinical practice, with a particular focus on those areas of high HBV infection rates. Expert commentary: A number of studies have assessed whether NA antiviral treatment can improve the prognosis of HBV-related HCC patients. In this review we evaluate the current evidence, including that from trials in Asia, for antiviral NA treatments in HBV-related HCC patients. We also focus on those NAs with a high genetic barrier to resistance (i.e. ETV or TDF), on different therapeutic approaches, and on the future evidence that is required in this field.

Review of the pharmacological management of hepatitis B viral infection before and after liver transplantation

The progress in treatment against hepatitis B virus (HBV) with the development of effective and well tolerated nucleotide analogues (NAs) has improved the outcome of patients with HBV decompensated cirrhosis and has prevented post-transplant HBV recurrence. This review summarizes updated issues related to the management of patients with HBV infection before and after liver transplantation (LT). A literature search using the PubMed/Medline databases and consensus documents was performed. Pre-transplant therapy has been initially based on lamivudine, but entecavir and tenofovir represent the currently recommended first-line NAs for the treatment of patients with HBV decompensated cirrhosis. After LT, the combination of HBV immunoglobulin (HBIG) and NA is considered as the standard of care for prophylaxis against HBV recurrence. The combination of HBIG and lamivudine is related to higher rates of HBV recurrence, compared to the HBIG and entecavir or tenofovir combination. In HBIG-free prophylactic regimens, entecavir and tenofovir should be the first-line options. The choice of treatment for HBV recurrence depends on prior prophylactic therapy, but entecavir and tenofovir seem to be the most attractive options. Finally, liver grafts from hepatitis B core antibody (anti-HBc) positive donors can be safely used in hepatitis B surface antigen negative, preferentially anti-HBc/anti-hepatitis B surface antibody positive recipients.

Current management of hepatitis B virus infection before and after liver transplantation

The progress in treatment against hepatitis B virus (HBV) has substantially improved the outcome of all HBV-infected patients. We systematically reviewed the existing data in the management of HBV transplant patients in order to assess the optimal regimen in the pretransplant setting, for post-transplant prophylaxis and for therapy of HBV recurrent infection. All data suggest that an effective pretransplant anti-HBV therapy prevents post-transplant HBV recurrence. Pretransplant therapy has been based on lamivudine with addition of adefovir upon lamivudine resistance, but the use of newer, potent high-genetic barrier agents is expected to improve long-term efficacy. Moreover, it may lead to improvement of liver function, which sometimes removes the need for transplantation, although more objective criteria for removal from waiting lists are required. After liver transplantation, the combination of HBV immunoglobulin and one nucleos(t)ide analogue, mostly lamivudine, is currently the best approach, almost eliminating the probability of HBV recurrence. Treatment of post-transplant HBV recurrence has been mainly studied with lamivudine, but it will be most effective with entecavir and tenofovir, which have a low risk of resistance. In conclusion, the newer anti-HBV agents improve the treatment of HBV both pretransplant and post-transplant. HBV immunoglobulin is still used in combination with an anti-HBV agent for post-transplant prophylaxis. Monoprophylaxis with one of the new anti-HBV agents might be possible, particularly in patients preselected as having a low risk of HBV recurrence, but further data are needed and strategies to ensure compliance must be used.

Chronic hepatitis B: early viral suppression and long-term outcomes of therapy with oral nucleos(t)ides

Chronic hepatitis B is a serious health problem worldwide with a substantial minority of patients experiencing premature death due to end-stage liver disease and/or hepatocellular carcinoma. Antiviral therapy may help prevent complications of chronic hepatitis B, and seven agents are currently approved in many countries. Of these agents, five are nucleos(t)ide analogs that all have a risk of antiviral drug resistance with long-term use. Efforts have been made in the recent years to prevent or to reduce the risk of viral resistance in patients treated with oral nucleos(t)ides as the majority of these patients will require therapy for 3-5 years or longer. One approach is to identify patients who would most likely develop antiviral resistance on long-term therapy using predictors obtainable early in the course of treatment, when intervention with new or additional therapy can be instituted. The most important predictors of treatment outcomes are serum HBV DNA levels at baseline and during the first 6 months of therapy. The purpose of this synopsis is to review the recent literature regarding the importance of serum HBV DNA levels in association with treatment outcomes in chronic hepatitis B, particularly the association of complete viral suppression early in the course of oral therapy with long-term treatment outcomes, particularly the incidence of antiviral drug resistance.

Current treatment indications and strategies in chronic hepatitis B virus infection

The optimal approach to the management of several marginal cases with chronic hepatitis B virus (HBV) infection is controversial. Serum HBV DNA and aminotransferase levels, and the degree of necroinflammation and fibrosis determine the therapeutic decisions. All patients with elevated aminotransferase (> twice the upper limit of normal) and serum HBV DNA above 20 000 IU/mL should be treated. Liver biopsy is important for therapeutic decisions in cases with mild aminotransferase elevations and serum HBV DNA below 20 000 IU/mL. Chronic HBV patients who do not receive treatment should be followed for life. There are seven agents licensed for chronic hepatitis B: standard and pegylated interferon-alpha, lamivudine, adefovir, entecavir, telbivudine and tenofovir. One-year courses with pegylated interferon-alpha induce sustained off-therapy remission in 30%-32% of patients with HBeAg-positive chronic hepatitis B and in a smaller proportion of patients with HBeAg-negative chronic hepatitis B. Oral antivirals achieve initial on-therapy responses in the majority of patients, but are intended as long-term therapies. Viral suppression has favourable effects on patients’ outcome and modifies the natural course of the disease. Viral resistance, however, is the major drawback of long-term oral antiviral therapy. Lamivudine monotherapy is associated with the highest and entecavir monotherapy with the lowest resistance rate so far. There has been no resistance to tenofovir, but after only 18 mo of treatment to date. The optimal first-line anti-HBV therapy with the best long-term cost/benefit ratio remains unclear. If oral antiviral agents are used, compliance should always be ascertained and HBV DNA levels should be regularly tested.

How to diagnose and treat hepatitis B virus antiviral drug resistance in the liver transplant setting

1. Hepatitis B virus variants with antiviral drug-resistant mutations and/or hepatitis B immune globulin-resistant mutations are the main cause of hepatitis B virus reinfections post-liver transplant. 2. Early diagnosis of antiviral drug resistance and prompt initiation of rescue therapy are important in preventing hepatitis flares and hepatic decompensation. 3. Virologic breakthrough is the first indication of antiviral drug resistance. 4. Genotypic resistance testing should be performed when possible to avoid unnecessary modification of treatment in patients who do not have confirmed antiviral drug resistance and to permit appropriate selection of rescue therapy in those who have confirmed antiviral drug resistance. 5. Choice of rescue therapy requires knowledge of the past history of hepatitis B virus treatments and virologic response to those treatments, patterns of mutations detected at the time of virologic breakthrough, and in vitro cross-resistance data. 6. Occurrence of antiviral drug resistance can be reduced by the use of the most potent nucleos(t)ide analogue(s) with the highest genetic barrier to resistance, emphasis of medication compliance, and close monitoring of virologic response.