Interferon-alpha 2b improves short-term survival in patients transplanted for chronic liver failure caused by hepatitis B

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.

Management of HBV Infection in Liver Transplantation Patients

In the absence of preventative therapy, reinfection of allografts with hepatitis B virus (HBV) after orthotopic liver transplantation (OLT) resulted in dismal allograft and patient survival. Major advances in the management of HBV-infected recipients of OLT during the past 15 years have steadily reduced the rate of reinfection, resulting in improved outcomes. Initially, long-term use of hepatitis B immune globulin (HBIG) as a source of anti-HBs antibodies was effective in preventing or delaying reinfection. Lamivudine monotherapy made it possible to suppress HBV replication prior to OLT, markedly decreasing the risk of reinfection. Although lamivudine monotherapy used before and after OLT could prevent reinfection, its effectiveness was limited by progressive development of lamivudine-resistant mutant infections. Combination therapy with HBIG and lamivudine after OLT reduced both HBV recurrence and the risk of lamivudine resistance even in patients with active HBV replication. Introduction of adefovir provided a safe, alternative oral antiviral able to treat effectively lamivudine-resistant mutants HBV. Available strategies to prevent reinfection have resulted in OLT outcomes for HBV-infected patients comparable to those for patients transplanted for non-HBV indications. In the future, combination therapies of HBIG and both nucleoside and/or nucleotide agents will undoubtedly be optimized. Development of new drugs to treat HBV will increase opportunities to combine agents to enhance safety, efficacy and prevent emergence of HBV escape mutants. New vaccines and adjuvants may make it possible to generate anti-HBs in immunosuppressed patients, eliminating the need for HBIG.

The clinical and immunologic impact of using interferon and ribavirin in the immunosuppressed host

1. Allograft infection with hepatitis C virus (HCV) in immunosuppressed adults results in decreased allograft and patient survival. 2. Risk factors for accelerated progression of hepatitis C related to immunosuppression include treated episodes of acute cellular rejection (ACR), pulse therapy with methylprednisolone, and use of OKT3. 3. Both interferon alfa (IFN-alpha) and ribavirin (RVN) show antiviral actions against HCV and stimulate innate and adaptive immunity to increase cytolysis and polarize T helper subtype 1 (T(H)1) responses. In addition, IFN-alpha inhibits fibrogenesis in the liver. 4. Both IFN-alpha and RVN have been studied in immunosuppressed liver transplant recipients as prophylaxis or treatment of established hepatitis C to reduce allograft failure and patient mortality. Reported protocols include monotherapies with RVN, standard IFN-alpha, and pegylated IFN-alpha and combination therapies using RVN and either standard IFN-alpha or pegylated IFN-alpha. 5. The clinical impact of using IFN-alpha and RVN in highly selected immunosuppressed patients varied among studies. Combination therapy with standard IFN-alpha and RVN resulted in the greatest sustained biochemical and virological responses. However, no therapy prevented progression of acute cholestatic hepatitis C despite evidence of virological responses. Substantial proportions of patients developed adverse events requiring dose reduction or discontinuation that compromised efficacy. RVN monotherapy was not only virologically ineffective, but may have stimulated hepatic fibrosis. Current data regarding monotherapy or combination therapy with pegylated IFN-alpha are limited, but encouraging. 6. Despite potent immunostimulatory actions of both IFN-alpha and RVN that enhance natural killer, T(H)1, their use did not significantly increase the incidence of ACR. 7. Additional studies are needed to resolve the controversy over prophylaxis versus treatment of established disease and the potential utility of low-dose maintenance IFN-alpha therapy to retard fibrogenesis without clearing HCV. 8. After new, less toxic, and more potent antiviral agents become available, they should be tested immediately in patients with hepatitis C post-liver transplantation.

Therapeutic management of hepatitis B-related cirrhosis

Hepatitis B virus (HBV) infection has a world-wide distribution, and may lead to cirrhosis, end-stage liver disease and hepatocellular carcinoma. Therapeutic strategies for HBV cirrhosis are changing rapidly. Treatment with interferon (IFN)-alpha may be hazardous and often can only be administered at low doses. The availability of lamivudine has revolutionized the treatment of chronic hepatitis B and opened up new options for the management of patients with decompensated cirrhosis or recurrent hepatitis B post-liver transplantation. However, lamivudine therapy should be weighed against the risk of selection of resistant mutants and randomized control trials are needed. Hopefully, in the near future, new antiviral drugs such as adefovir dipivoxil which is active on lamivudine-resistant mutants will become available. IFN-alpha is still the only molecule which may prevent HBV-induced hepatocarcinogenesis in humans. Whether other antivirals will also prove useful warrants further follow-up studies.

Hepatitis B e antigen seroconversion: effects of lamivudine alone or in combination with interferon alpha

Seroconversion of hepatitis B e antigen (HBeAg) is an important marker for resolution of active hepatitis B virus (HBV) infection and for a long-term positive response to treatment. Lamivudine, a nucleoside analogue, is the first effective oral treatment for chronic hepatitis B in patients with evidence of viral replication and liver disease. When appropriate patient groups are compared, treatment with lamivudine for 1 year leads to HBeAg seroconversion in a similar proportion of patients as a standard course of interferon (IFN) alpha therapy. Seroconversion increases during prolonged therapy (up to 3 years), and is sustained post-treatment in more than three-quarters of patients. Response rates are related to the pretreatment level of serum alanine aminotransferase (ALT) and reach 65% in those patients with serum ALT > 5 x upper limit of normal (ULN) after one year. For patients with pretreatment ALT > 2 x ULN, response was seen in 38% after one year, rising to 65% after 3 years. To date, combination with IFN and lamivudine has not been shown to confer additional benefit compared with lamivudine monotherapy. Lamivudine is effective and appropriate for use in a greater proportion of HBV infected patients than IFN alpha, particularly those infected at birth or in early childhood. Furthermore, because seroconversion after lamivudine is not normally associated with a severe flare of liver disease, as seen with IFN, it is more suitable for use in patients with active liver disease and cirrhosis. In conclusion, lamivudine is more suitable than IFN for a broad range of patients, including those with severe liver disease, recurrent flares, pre-core mutant HBV and those who have failed previously IFN treatment or are immunosuppressed. Lamivudine is also better tolerated than IFN.

Lamivudine for hepatitis B in clinical practice

Lamivudine is a potent, once-daily, oral antiviral therapy that is effective and well tolerated in most patient groups with chronic hepatitis B virus infection, including those with pre-core mutant infection. Studies to date show that lamivudine suppresses serum viral replication, causing reductions in serum hepatitis B virus (HBV) DNA and enhancing hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg plus presence of antibodies to HBeAg [anti-HBe]). Lamivudine also improves liver disease, as shown by normalisation of alanine transaminase (ALT) levels and reduced progression to cirrhosis. Lamivudine is effective in patients who are interferon (IFN) alpha naïve and in those who have failed to respond to IFN alpha, and it suppresses HBV in decompensated liver disease and in liver transplantation. Variants with mutations in the YMDD (tyrosine-methionine-aspartate-aspartate) motif may emerge with prolonged lamivudine therapy, but most patients maintain clinical control. Lamivudine has a safety profile similar to that of placebo and it is better tolerated than IFN alpha. In conclusion, lamivudine represents a major advance in the therapeutic options available for the management of patients with chronic hepatitis B and should now be considered the drug of choice for most patients who require treatment.

Resolution of recurrent hepatitis B in two liver transplant recipients treated with famciclovir

Recurrent hepatitis B infection after orthotopic liver transplantation remains problematic despite prophylaxis with hepatitis B immune globulin (anti-HBs IgG). Recently, famciclovir (an oral nucleoside analog) has been shown to have potent antiviral activity against hepatitis B in vitro as well as in patients with chronic hepatitis B. We present two patients who developed recurrent hepatitis B after orthotopic liver transplantation and were treated with famciclovir, 500 mg t.i.d. Both patients subsequently responded with marked improvement in biochemical liver tests and histology, with subsequent loss of hepatitis B surface antigen. Famciclovir is a useful agent in the treatment of hepatitis B in the liver transplant recipient.