Long-term follow-up of a randomized trial of interferon therapy for chronic hepatitis B in a predominantly homosexual male population

Causes of and prevention strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a challenging malignancy of global importance. It is associated with a high rate of mortality and its prevalence in the United States and in Western Europe is increasing. Cirrhosis is the strongest and the most common known risk factor for HCC, usually due to hepatitis C virus (HCV) and hepatitis B virus (HBV) infections. However, different lines of evidence identify in non-alcoholic fatty liver disease (NAFLD) a possible relevant risk factor for occurrence of HCC. Given the continuing increase in the prevalence of obesity and diabetes, the incidence of non-alcoholic steatohepatitis-related HCC may also be expected to increase, and a potential role of behavior treatment and/or insulin-sensitizing drugs can be envisaged. Vaccination against HBV is the most efficient primary prevention measure currently available to reduce the HCC incidence and mortality in high-incidence areas, while data on the role of interferon (IFN) and nucleos(t)ide analogues (NUC) are still controversial. The pooling of data from the literature suggests a slight preventive effect of antiviral therapy on HCC development in patients with HCV-related cirrhosis, but the preventive effect is limited to sustained virological responders.

Special Considerations and Treatment of Patients with HBV-HIV Coinfection

Coinfection with HIV and hepatitis B virus (HBV) substantially alters the natural course of HBV infection as well as its management. Therapy for HBV infection in HIV-coinfected patients requires several factors to be taken into consideration, such as whether the antiviral activity of a particular agent is specific for HBV (that is, adefovir, entecavir, telbivudine and pegylated interferon) or for both viruses (that is, lamivudine, emtricitabine and tenofovir), whether the chosen drug has the potential for inducing drug resistance and cross-resistance, and whether use of the agent is associated with hepatotoxicity. For coinfected patients who do not require therapy for their HIV infection, clinicians should avoid prescribing monotherapy with agents that have activity against HIV (that is, tenofovir, entecavir, emtricitabine or lamivudine) so as not to compromise future HIV care. This review discusses the current status of treatment of hepatitis B in the setting of HIV infection. It describes emerging therapeutic strategies and addresses challenges in the treatment of coinfection.

Prevention of hepatocellular carcinoma

The accuracy and the reliability of well-recognized clinical, virologic, histologic, and molecular risk factors for hepatocellular carcinoma are still insufficient; thus, accurate risk prediction of developing cancer in individual patients remains an elusive goal.

Treatment of hepatitis B with interferon and combination therapy

Pegylated interferon alpha-a (40 kDa) has recently been shown to be superior to conventional interferon. Furthermore, in a pilot study, pegylated interferon alpha-2b together with lamivudine was superior to lamivudine monotherapy. Therefore, the pegylated interferons alone or in combination with antiviral agents are likely to be the treatment of the future. Selecting patients for treatment and knowing when to treat them is as important as knowing which medicine to treat them with.

Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures

Hepatitis B virus (HBV) infection is a serious global health problem, with 2 billion people infected worldwide, and 350 million suffering from chronic HBV infection. The 10th leading cause of death worldwide, HBV infections result in 500 000 to 1.2 million deaths per year caused by chronic hepatitis, cirrhosis, and hepatocellular carcinoma; the last accounts for 320 000 deaths per year. In Western countries, the disease is relatively rare and acquired primarily in adulthood, whereas in Asia and most of Africa, chronic HBV infection is common and usually acquired perinatally or in childhood. More efficacious treatments, mass immunization programs, and safe injection techniques are essential for eliminating HBV infection and reducing global HBV-related morbidity and mortality. Safe and effective vaccines against HBV infection have been available since 1982. The implementation of mass immunization programs, which have been recommended by the World Health Organization since 1991, have dramatically decreased the incidence of HBV infection among infants, children, and adolescents in many countries. However, not all countries have adopted these recommendations and there remains a large number of persons that were infected with HBV prior to the implementation of immunization programs. Antiviral treatment is the only way to reduce morbidity and mortality from chronic HBV infection. Conventional interferon alfa and lamivudine have been the primary treatments to date. Conventional interferon alfa produces a durable response in a moderate proportion of patients but has undesirable side-effects and must be administered subcutaneously three times per week. Lamivudine also produces a response in a modest proportion of patients and causes few side-effects. However, prolonged treatment is often necessary to prevent relapse on cessation of therapy, and continuous treatment can lead to the development of lamivudine resistance. Promising emerging new treatments include adefovir, entecavir and peginterferon alfa-2a (40 kDa).

Short- and long-term effects of treatment of chronic hepatitis B and delta virus by IFN

Chronic hepatitis B virus (HBV) infection is a common infectious disease in the world. Two percent of the patients with chronic HBV infection will develop cirrhosis each year, and will die prematurely from cirrhosis or hepatocellular carcinoma. So far interferon alfa and lamivudine are the only effective drugs. Interferon alfa can be used at the dosage of 9-10 million units thrice a week for 4-6 months either intramuscularly or subcutaneously for standard treatment. Interferon provides sustained response in 1/3 of the patients when HBe Ag is (+). Response rate to interferon therapy in HBe Ag(-) patients was similar to that reported in HBe Ag(+) ones. However the responses were not sustained in many patients, serum HBV-DNA reappear in most after stopping the treatment. Extension of therapy to 1 year may be needed in patients who are unresponsive to therapy and having HBV-DNA levels <10 pg/ml and ALT >100 IU. Establishment of unresponsiveness in early phases of the therapy is important and careful follow up of serum HBe Ag may be helpful. Interferon alfa treatment of chronic HDV infection may result in temporary normalization of ALT values. Disappearance of HBV-DNA and HBs Ag from the serum upon completion of therapy dictates sustained response in chronic HDV infection. The long term effect of interferon with respect to virological and histopathological responses is poor in HDV infection and longer periods of therapy in higher doses may be beneficial.

Clinical and virological aspects of hepatitis B co-infection in individuals infected with human immunodeficiency virus type-1

The improved prognosis of HIV-infection that has occurred since the introduction of highly active antiretroviral therapy (HAART) has resulted in renewed emphasis being placed on co-morbidities associated with HIV-infection, and chronic viral hepatitis in particular. Hepatitis B virus (HBV) infection is an important infection in HIV-1 infected individuals because of the influence of HIV-1 co-infection on the natural history of HBV infection. Antiviral therapies with activity against both viruses have enabled targeted therapy in co-infected individuals, however, optimism regarding improved prognosis has been tempered by the development of antiviral resistant HBV. Emerging new classes of HBV therapies herald the possibility of combination HBV therapy.

Influence of HIV infection on the response to interferon therapy and the long-term outcome of chronic hepatitis B

BACKGROUND & AIMS

The outcome of chronic hepatitis B and the efficacy of interferon alfa (IFN-alpha) remain controversial in human immunodeficiency virus (HIV)-positive patients. We analyzed the influence of HIV coinfection on the response to IFN-alpha therapy, long-term virologic status, progression to cirrhosis, and mortality.

METHODS

This was a retrospective follow-up cohort study of 141 consecutive hepatitis B e antigen-positive patients (69 HIV positive) followed up for 45 months.

RESULTS

The short-term response to IFN-alpha therapy was not significantly different in HIV-positive and HIV-negative patients (28% vs. 51%; P = 0.06) but was poorer in cases of low CD4 cell count (P = 0.038). The hepatitis B virus (HBV) reactivation rate was higher in HIV-positive patients (P = 0.033) and was associated with low CD4 cell count. The risk of cirrhosis was higher in HIV-positive patients with a CD4 cell count <200/mm(3) (relative risk [RR], 4.57; P = 0.007), in IFN-alpha-untreated patients (RR, 2.63; P = 0.041), in patients older than 33 years (RR, 4.59; P = 0.008), and in cases of high necroinflammatory score at baseline (RR, 1.27; P = 0.010). Cirrhosis-related death was more frequent in HIV-positive patients with low CD4 cell count at baseline (P = 0.041), in alcohol consumers (P = 0.001), in IFN-alpha-untreated patients (P = 0.052), and in patients with high histology activity index at baseline (P = 0.005).

CONCLUSIONS

HIV coinfection was associated with poorer response to IFN-alpha therapy, more frequent HBV reactivations, and increased incidence of cirrhosis and cirrhosis-related death in cases of low CD4 count. IFN-alpha therapy decreased the incidence of HBV cirrhosis regardless of HIV status or serologic response.

Management of viral hepatitis B

Hepatitis B virus (HBV) infection is a major global health concern and is the most common cause of chronic liver disease worldwide. The natural history and clinical outcomes of chronic HBV infection are determined by the viral replication cycle and the host immune responses. Treatment of chronic hepatitis B is directed at interrupting the natural history by suppressing HBV replication before development of any significant irreversible liver cell damage. Effective antiviral therapies should be followed by sustained suppression of HBV-DNA, normalization of transaminases levels and a stable stage of HBeAg seroconversion with persistence of circulating anti-HBeAg antibodies. Two major classes of antiviral therapeutic agents that have been approved for treatment of chronic hepatitis B are immunomodulating agents (i.e. interferon) and the nucleoside analogs (i.e. lamivudine). A 4-6 month course of interferon-alpha has resulted in improvement of survival in 20%-30% of patients with chronic hepatitis B who had elevated serum ALT levels without hepatic decompensation. Interferon-alpha therapy is associated with HBeAg seroconversion; normalization of ALT levels, reduced hepatic inflammation, and possibly reduced disease progression to cirrhosis and hepatocellular carcinoma. Interferon can also be used with caution in patients with early compensated cirrhosis. A 12-month course of lamivudine has been shown to be well tolerated and effective. Lamivudine can be used in decompensated cirrhosis and immunosuppressed patients and for prevention of recurrent HBV infection after liver transplantation. The response rates after 3 years of lamivudine therapy account for 40-65%. A major problem of antiviral treatment is the emergence of drug resistance conferred by mutations in the YMDD motif of HBV reverse transcriptase. The prevalence of YMDD mutations increases with longer durations of antiviral therapies and this has been detected in 20% of immunocompetent patients receiving lamivudine per year. Contentious issues remain when to stop the treatment if HBeAg seroconversion does not occur. Many new immunomodulatory therapies and antiviral agents are in various stages of clinical development and have shown some promise. Among newer HBV antivirals, adefovir dipivoxil, entecavir, emtricitabine, DAPD and clevudine appear to be at least as potent as lamivudine in suppressing HBV replication. In vitro studies have shown that YMDD mutations confer cross-resistance between lamivudine and emtricitabine. However, adefovir, dipivoxil, lobucavir, DAPD and possibly clevudine suppress replications of both YMDD mutants and wild types of HBV. Immunomodulatory approaches for treatment of chronic hepatitis B are conceptually attractive, but newer agents used to date (thymosin-alpha, interleukin-12, therapeutic vaccines) have not demonstrated sufficient efficacy for widespread use. Combinations of an immunomodulatory agent and nucleoside analog may improve the therapeutic efficacy and reduce the emergence of drug resistance. Nevertheless, combinations of interferon and lamivudine therapies do not confer such additional benefits. The next challenge for HBV treatment is to use antivirals in combination and/or in cyclical therapy to minimize the emergence of drug resistance and increase efficacy, particularly to achieve sustainable post-treatment suppression of HBV. Randomized prospective control trials of combined antiviral therapies given simultaneously or sequentially are needed to establish safe and effective combined regimens that can be recommended for future treatment strategies.

Current treatment strategies for chronic hepatitis B and C

For chronic hepatitis B, treatment with a 4-month course of interferon alfa-2b can achieve hepatitis B e antigen seroconversion, normalization of aminotransferase levels, reduced hepatic inflammation, and possibly reduced progression to cirrhosis and improvement in survival in 20%-30% of patients. Similar results can be achieved with a 12-month course of lamivudine, with response rates increasing to 40%-65% after 3 years of therapy. Interferon can also be used in early cirrhotic patients, and lamivudine can be used in advanced cirrhotics and immunosuppressed patients. Combination interferon and lamivudine therapy does not confer additional benefits. For chronic hepatitis C, the combination of interferon alfa-2b and ribavirin is the treatment of choice, offering superior sustained response rates (40%) compared with interferon alone (15%). Therapy should be administered for 12 months to patients with genotype 1 virus but for only 6 months to patients with genotypes 2 and 3. Patients experiencing relapse after 6 months of interferon monotherapy can be re-treated with interferon and ribavirin or high-dose interferon, with 45%-56% sustained response rates. However, relatively few patients who are prior nonresponders to interferon monotherapy will have sustained response to further interferon-based treatments, including combination therapy with ribavirin. Successful therapy not only leads to the eradication of viral RNA but also may delay progression to cirrhosis and hepatocellular carcinoma. Interferon combined with polyethylene glycol (PEG), shows promise as an improved formulation of interferon with yet higher sustained response rates.

Combination chemotherapy for hepatitis B virus: the path forward?

Hepatitis B virus (HBV) was identified as a cause of viral hepatitis more than 30 years ago and hepatitis B vaccines have been available for almost 20 years, but HBV infection continues to be a global health problem, responsible for about 1.2 million deaths annually. By the end of this year, almost 400 million people--about 5% of the world's population and more than ten times the number infected with human immunodeficiency virus (HIV)--will be infected with HBV. Chemotherapy remains the only treatment option for controlling chronic HBV infection once acquired, but none of the many different chemotherapeutic strategies used in the past has proven consistently successful. Prospects for successful treatment of HBV have improved dramatically during the past decade due to the development of new, well tolerated and efficacious anti-HBV drugs, and to advances in our understanding of HBV replication and pathogenesis. The newer anti-HBV drugs are capable of reducing viral loads very rapidly, but the initial response is invariably followed by very much slower elimination of residual virus. As more effective anti-HBV drugs become available, the emergence of drug resistance during the slower phase of HBV elimination will probably become the most significant obstacle in the way of eventual control of HBV infection. Experience with HIV indicates that combination chemotherapy may suppress or eliminate drug resistance and methods for pre-clinical and clinical assessment of anti-HBV drug combinations are being developed. Basic research into mechanisms of drug action and interaction should assist in the design and optimisation of combination chemotherapy for HBV infection, for which additional new anti-HBV drugs will undoubtedly be required in future.

Hepatitis B

The management of acute HBV infection is supportive. Specific treatment is not indicated for HBV carriers because they often have no evidence of liver injury, and, further, do not respond to currently available therapies. Interferon monotherapy is best indicated for patients with chronic replicating HBV infection and evidence of chronic hepatitis. There is an increased likelihood of clearing HBsAg with interferon monotherapy as compared to lamivudine. Lamivudine is an oral nucleoside analog that is better tolerated than interferon. The clinical situations for its use are far more than interferon monotherapy. Lamivudine should be used in patients with decompensated cirrhosis and also in transplantation, both before and after transplantation. The post-transplant use of hepatitis B immune globulin (HBIG) and lamivudine combination therapy may be better for recipients who are identified in a replicative phase prior to transplantation. Hepatitis B coinfection with one or more viruses, HCV, HDV, or HIV, may occur. Both interferon and lamivudine have been useful in these patients. However, the data are sparse and heterogeneous. Therapy with one or both drugs will have to be tailored to the clinical situation. Combination therapy with immunomodulatory and/or antiviral drugs are what we will be looking toward in the future.