Successful treatment with tenofovir in a child C cirrhotic patient with lamivudine-resistant hepatitis B virus awaiting liver transplantation. Post-transplant results

Prevention of hepatitis B virus-associated liver diseases by antiviral therapy

Hepatitis B virus (HBV) is a major cause of acute and chronic hepatitis, cirrhosis and hepatocellular carcinoma, particularly in Asia-Pacific countries. The major complications in HBV carriers are hepatocellular carcinoma (HCC), liver failure and esophageal varices following the progression to cirrhosis, while some develop HCC without cirrhosis. The progression to liver fibrosis and these other complications could be prevented by treatment with nucleos(t)ide analogues (NUCs); however, NUCs must be continuously administered for a long time. Peginterferon could lead to HBV surface antigen loss. It is difficult to use peginterferon in HBV-infected patients with decompensated cirrhosis. Acute liver failure due to HBV infection and acute exacerbation of chronic hepatitis B could be treated by NUCs. Universal vaccination programs against HBV could prevent new HBV infections globally. Here, we review the currently available treatments for HBV infection.

Advances in treatment of HBV-related liver failure with nucleoside analogues

Hepatitis B virus (HBV) infection is a common cause of liver failure in China. The mortality of fulminant hepatitis B is more than 70%. Adoption of antiviral therapy or not on the basis of comprehensive treatment has become a hot topic of recent research of treatment of fulminant hepatitis B, which causes liver failure in a way different from other reasons. HBV replication plays a critical role in initiating the development of fulminant hepatitis B. Reducing viral load to alleviate excessive immune response by antiviral therapy represents a new idea for the treatment of fulminant hepatitis B. The advent of nucleoside analogues makes it possible to conduct antiviral therapy against fulminant hepatitis B. This article summarizes recent advances in treatment of HBV-related liver failure with nucleoside analogues.

Management of end-stage liver disease in chronic hepatitis B

The consequences of chronic hepatitis B virus infection include hepatocellular carcinoma and liver cirrhosis. Effective antiviral therapy in patients with hepatitis B with advanced liver disease with viral suppression and sustained HBeAg seroconversion (where applicable) may abort hepatic decompensation, diminish hepatocellular risk, and reduce the risk of viral recurrence after transplantation. Overt hepatic decompensation is an indication for referral to a transplant center.

Tenofovir and its potential in the treatment of hepatitis B virus

Recent literature is reviewed about treatment of chronic hepatitis B virus (CHB), focusing on tenofovir disoproxil fumarate (TDF; Viread((R))), among the nucleotide and nucleoside analogs. TDF pharmacokinetics and pharmacodynamics, activity in respect of hepatitis B virus (HBV) multi-drug-resistant mutations, efficacy in treatment-naïve and treatment-experienced patients, and side effects are described. The most predictive response factors to TDF therapy are discussed and all available combination therapies to optimize clinical outcome in the various patient profiles are analyzed, such as compensated and/or decompensated cirrhotic patients. The use of TDF in pregnancy, and prophylaxis after exposure to HBV and post-liver transplantation are also evaluated.

Role of tenofovir in the treatment of chronic HBV infection

Nucleoside analogues revolutionized the treatment of chronic HBV infection and have become the most important therapeutic option within the last decade. Currently, the nucleoside analogues lamivudine, telbivudine and entecavir, and the nucleotide analogue adefovir dipivoxil, are licensed. Tenofovir disoproxil fumarate (TDF) is another acyclic nucleotide analogue that has been successfully used in the treatment of HIV-infected patients, but has demonstrated significant antiviral activity in wild-type and lamivudine-resistant HBV infections. The use of TDF 300 mg/day leads to marked suppression of HBV replication below the detection limit in different patients groups with HBV mono- or HIV/HBV co-infection in most instances, and a remarkably high rate of hepatitis B e antigen loss and even hepatitis B surface antigen loss was found in small, uncontrolled studies. Belonging to the substance class of acyclic nucleotide analogues, TDF is not cross-resistant to nucleoside analogue resistance-associated mutations. In equal dosages, TDF has comparable antiviral potency as compared with its congender adefovir dipivoxil, but in clinical studies exhibits higher antiviral efficacy and generates a higher genetic barrier against the development of genotypic HBV resistance due to its approximately 24-fold higher dosage. Owing to the numerous newly developed compounds and as a consequence of the emerging problem of drug resistance, treatment concepts for chronic hepatitis B will certainly be modified in the future. Because of its quite favorable antiviral and safety properties, TDF will likely be highly regarded in the management of HBV infections in the future.

Hepatitis B and end-stage liver disease

Hepatitis B virus (HBV) is the most common cause of chronic hepatitis and end-stage liver disease worldwide. Untreated, chronic hepatitis B acquired early in life results in cirrhosis, liver failure, or hepatocellular carcinoma in up to 40% of individuals. Until recently, the options for a patient who had end-stage hepatitis B cirrhosis were severely limited, but during the past 15 years great strides have been made in prevention and treatment of hepatitis B cirrhosis. This article reviews recent advances in the understanding of the natural history, prevention, and medical management of HBV-related end-stage liver disease.

Management of hepatitis B in liver transplant recipients

Advances in hepatitis B virus (HBV) antiviral prophylaxis have dramatically improved graft and patient survival for patients undergoing liver transplantation for hepatitis B related end-stage liver disease. In particular, the availability of hepatitis B immune globulin (HBIg) in combination with nucleos(t)ide analogues such as lamivudine and adefovir, have transformed outcomes. The availability of newer antivirals such as adefovir, tenofovir and entecavir either as monotherapy or in combination offer an increasing number of antiviral options. Despite these advances, significant challenges remain. Factors that affect the efficacy of anti-viral therapy include detectable HBV viraemia at the time of transplant and emergence of HBV mutants (especially in patients with prior exposure to lamivudine). HBV prophylaxis protocols are expensive especially with use of high-dose HBIg and newer nucleos(t)ide analogues. This review summarizes current HBV prophylaxis protocols and management of recurrent disease post-transplantation. There is an increasing need for individualization of therapy based on prior drug exposures, level of HBV DNA at time of transplantation and type of prophylaxis used.

Improvements in Parameters of End-Stage Liver Disease in Patients with HIV/HBV-related Cirrhosis Treated with Tenofovir

Background

Mortality related to end-stage liver disease is increasing in HIV/hepatitis B virus (HBV)-coinfected patients and effective treatment options are limited. Tenofovir is now widely used in HIV/HBV coinfection and results in significant HBV suppression, in both patients with and patients without lamivudine resistance. The safety and efficacy of tenofovir in HIV/HBV cirrhosis has not been previously described.

Methods

Seven cirrhotic HIV/HBV patients treated with tenofovir were identified within the HIV clinic. Parameters of hepatic function, CD4+ T-cell counts, HBV DNA levels and Child-Pugh Class (C-P-C) were determined before and after addition of tenofovir. All patients had prior lamivudine experience with a median baseline HBV DNA of 6.23x107 copies/ml.

Results

Four of seven patients were C-P-C -A and hepatitis ‘e’ antigen (HBeAG) was positive in 4/7 patients. After a median duration of tenofovir of 28 months, all laboratory parameters improved, with significant changes in albumin and prothrombin (PT) (median pre-/post-tenofovir: alanine aminotransferase 63/39; bilirubin 26/18; albumin 39/44, P=0.028; PT 17.5/15, P=0.018). All three patients with C-P-C -B or -C improved to C-P-C -A, which for one patient enabled removal from the liver transplant waiting list. Three patients lost HBeAG with two anti-HBe seroconversions. Median HBV DNA was suppressed to <35 copies/ml.

Conclusions

This study demonstrates that tenofovir can produce HBV viral suppression, HBeAg seroconversion and improvement in markers of hepatic function in HIV/HBV-coinfected patients with cirrhosis. The potential reversal of end-stage liver disease may provide an important survival benefit in this population.

Hepatitis B in liver transplant recipients

1. The use of low-dose immunosuppressive therapy along with pre- and posttransplantation nucleos(t)ide therapy and posttransplantation hepatitis B immunoglobulin (HBIG) has yielded marked improvements in survival. 2. Lamivudine (Epivir-HBV), adefovir (Hepsera), entecavir (Baraclude), tenofovir (Viread), emtricitabine (Emtriva), and the combination drugs tenofovir + emtricitabine (Truvada) and abacavir + lamivudine (Epzicom) are effective nucleos(t)ide antiviral agents that, in some cases, may help reverse liver disease sufficiently to avoid transplant. 3. In posttransplantation patients, virus suppression with some combination of HBIG and the nucleos(t)ide agents may prevent graft loss and death or the need for a second transplant. 4. In both the pre- and posttransplantation setting, the goal of hepatitis B virus management is complete virus suppression. 5. The use of low-dose intramuscular HBIG is evolving, with studies showing that dosing and cost can be reduced by 50-300% with a customized approach. 6. Elimination of HBIG from the treatment paradigm is currently under evaluation and may be possible with the use of newer medications that have no or low resistance rates. 7. Although there is growing evidence that some types of combination therapy may decrease the chance that drug resistance will develop and increase the likelihood of long-term success in preventing graft loss and death, additional research will be required to determine which combinations will work well in the long term, and which will not.

Prevention and treatment of recurrent Hepatitis B after liver transplantation: the current role of nucleoside and nucleotide analogues

The Hepatitis B virus (HBV) is a DNA virus that can cause both acute and chronic liver disease in humans. Approximately 350–400 million people are affected worldwide and up to one million deaths occur annually from cirrhosis and hepatocellular carcinoma. When cirrhosis and liver failure develop, the definitive treatment of choice remains orthotopic liver transplantation (OLT). In the past, an unacceptable HBV recurrence rate with a high rate of graft loss was noted. The use of Hepatitis B immunoglobulin (HBIG) has resulted in improved patient and graft survival rates. The addition of the nucleoside analog Lamivudine (LAM) to HBIG has improved these survival curves to an even greater degree. Prolonged use of LAM will almost invariably lead to the development of viral mutations resistant to the drug. There are now several other nucleoside and nucleotide analogs (Adefovir, Entecavir, Tenofovir, and Truvada) available for the clinician to utilize against these resistant strains. It should be possible to prevent recurrence in most, if not all, post-transplant patients and also to significantly reduce viral loads with normalization of transaminases in those who have developed recurrent infection. The antiviral regimen should be robust and minimize the risk of breakthrough mutations. A prudent approach may be the implication of combination antiviral therapy. This review summarizes the efficacy of previous regimens utilized to prevent and treat recurrent HBV following OLT. Particular attention will be paid to the newer nucleoside and nucleotide analogs and the direction for future strategies to treat HBV in the post transplant setting.