Safety and efficacy of adefovir dipivoxil in patients infected with lamivudine-resistant hepatitis B and HIV-1

Favipiravir Inhibits Hepatitis A Virus Infection in Human Hepatocytes

Hepatitis A virus (HAV) is a causative agent of acute hepatitis and can occasionally induce acute liver failure. However, specific potent anti-HAV drug is not available on the market currently. Thus, we investigated several novel therapeutic drugs through a drug repositioning approach, targeting ribonucleic acid (RNA)-dependent RNA polymerase and RNA-dependent deoxyribonucleic acid polymerase. In the present study, we examined the anti-HAV activity of 18 drugs by measuring the HAV subgenomic replicon and HAV HA11-1299 genotype IIIA replication in human hepatoma cell lines, using a reporter assay and real-time reverse transcription polymerase chain reaction, respectively. Mutagenesis of the HAV 5’ untranslated region was also examined by next-generation sequencing. These specific parameters were explored because lethal mutagenesis has emerged as a novel potential therapeutic approach to treat RNA virus infections. Favipiravir inhibited HAV replication in both Huh7 and PLC/PRF/5 cells, although ribavirin inhibited HAV replication in only Huh7 cells. Next-generation sequencing demonstrated that favipiravir could introduce nucleotide mutations into the HAV genome more than ribavirin. In conclusion, favipiravir could introduce nucleotide mutations into the HAV genome and work as an antiviral against HAV infection. Provided that further in vivo experiments confirm its efficacy, favipiravir would be useful for the treatment of severe HAV infection.

Management of chronic hepatitis B in patients from special populations

Here we review the management of chronic hepatitis B (CHB) in four special categories of patients: CHB in pregnancy, in patients on immunosuppressive treatments, in patients undergoing liver transplantation, and in patients coinfected with human immunodeficiency virus (HIV) or hepatitis C virus (HCV).

Hepatitis B virus coinfection in human immunodeficiency virus-infected patients: A review

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to the shared modes of transmission, coinfection with HBV and human immunodeficiency virus (HIV) is not uncommon. It is estimated that 10% of HIV-infected patients worldwide are coinfected with HBV. In areas where an HBV vaccination program is implemented, the HBV seroprevalence has declined significantly. In HIV/HBV-coinfected patients, HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy (cART) is initiated, while HIV infection increases the risk of hepatitis events, cirrhosis, and end-stage liver disease related to chronic HBV infection. With the advances in antiviral therapy, concurrent, successful long-term suppression of HIV and HBV replication can be achieved in the cART era. To reduce the disease burden of HBV infection among HIV-infected patients, adoption of safe sex practices, avoidance of sharing needles and diluent, HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches. However, due to HIV-related immunosuppression, using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients.

Adefovir dipivoxil in chronic hepatitis B: history and current uses

INTRODUCTION

The nucleotide analogue adefovir dipivoxil (ADV) was approved in 2002 for the treatment of chronic infection with hepatitis B virus (HBV), in both hepatitis B e antigen (HBeAg)-positive and -negative patients. ADV 10 mg daily has been associated with improved liver histology, decreased levels of HBV DNA and alanine aminotransferase (ALT), and seroconversion of HBeAg.

AREAS COVERED

This paper reviews the use of ADV as a first-line treatment for chronic hepatitis B and as an add-on therapy in chronic HBV-infected patients with lamivudine resistance. In the years since its launch, clinical resistance to ADV has emerged, and tenofovir and entecavir have shown greater efficacy in reducing viral load.

EXPERT OPINION

Many patients who started antiviral therapy with ADV (either as monotherapy or in combination with lamivudine) remain on this agent because they have undetectable viremia, but its future use will probably diminish because of the availability of more potent drugs. ADV is generally well tolerated, though the 10 mg dose is associated with low risk of nephrotoxicity.

Nephrotoxicity, including acquired Fanconi's syndrome, caused by adefovir dipivoxil - is there a safe dose?

WHAT IS KNOWN AND OBJECTIVE

Adefovir dipivoxil (ADV) is an oral bioavailable prodrug of adefovir that possesses potent in vitro activity against hepadnaviruses, retroviruses and herpes viruses. ADV is excreted unchanged in the urine through glomerular filtration and tubular secretion and is known to be nephrotoxic at doses of 60mg daily and above. Thus, the long-term safety of ADV, particularly nephrotoxicity, is a major concern. Our objective is to comment on the nephrotoxcicity of low-dose (10mg daily) ADV through a case report.

COMMENT

The clinical features of nephrotoxicity because of ADV are described. A case report of acquired Fanconi's syndrome in a chronic hepatitis B patient treated with ADV 10mg daily is used to illustrate several key aspects.

WHAT IS NEW AND CONCLUSION

Adefovir dipivoxil can be nephrotoxic at conventional dosage and therefore, patients treated with long-term ADV should have regular monitoring of renal function, and calcium and phosphate levels.

Treatment of hepatitis B virus-associated nephropathy

Epidemiological studies have shown a relationship between hepatitis B virus (HBV) infection and development of proteinuria in some patients (most commonly children), with a predominance for male gender and histological findings of membranous nephropathy on renal biopsy. The presence of immune complexes in the kidney suggests an immune complex basis for the disease, but a direct relation between HBV and membranous nephropathy (or other types of glomerular diseases) remains to be proven. Clearance of HBV antigens, either spontaneous or following antiviral treatments results in improvement in proteinuria. Thus, prompt recognition and specific antiviral treatment are critical in managing patients with HBV and renal involvement. The present review focuses on treatment of HBV with special emphasis given to antiviral therapies, its complications, and dosing in patients with HBV-associated kidney disease.

[Long-term therapy for chronic hepatitis B in HIV co-infected patients]

As human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are acquired through the same routes of contamination, the prevalence of HBV serological markers found in the HIV-infected population is approximately 7%. Liver-related mortality and morbidity is higher in HIV/HBV co-infected patients than in HBV mono-infected patients. Both viruses must be considered before a treatment decision is made. According to the European consensus conference on the treatment of chronic hepatitis B and C in HIV coinfected patients, treatment is based on whether there is an existing indication of anti- HIV therapy or not. In patients with no indication of anti-HIV therapy, drugs with dual anti-viral activity (lamivudine, entecavir, tenofovir disoproxil fumarate) should not be used due to the risk of developing HIV-resistance. Interferon or adefovir in combination with telbivudine are recommended. In patients with an indication of anti-HIV therapy, a backbone of highly active anti-retroviral therapy should include tenofovir in combination with lamivudine or emtricitabine. The same regimen is recommended in patients who develop lamivudine resistance.

Virology and clinical sequelae of drug-resistant HBV in HIV-HBV-coinfected patients on highly active antiretroviral therapy

Several of the nucleoside/nucleotide analogues used to treat HIV also inhibit HBV replication, with lamivudine being the oldest of this group. Thus, prior to licensing of tenofovir, many HIV-HBV-coinfected individuals received lamivudine as the only drug active against HBV as part of an anti-HIV regimen, which set the stage for the emergence of drug-resistant HBV. In coinfected persons, lamivudine-resistant HBV develops more rapidly than in HBV-monoinfected persons, but it is not known if this is true for the newer agents. Owing to overlapping reading frames of the HBV polymerase and surface antigens, drug-resistant changes in HBV Pol can lead to mutations in the envelope. This review will discuss studies of drug-resistant HBV in HIV-infected persons including drug-resistant mutations that have been identified and clinical sequelae of these mutations.

A Systematic Review of Side Effects of Nucleoside and Nucleotide Drugs Used for Treatment of Chronic Hepatitis B

Although nucleosides and nucleotides have a good safety record for the treatment of hepatitis B, there have been no systematic reviews on this topic. We searched Medline to include studies of the oral antiviral agents for hepatitis B and adverse events, with at least 48 weeks of follow-up from the initiation of treatment with the drug. Important toxicities include nephrotoxicity, myopathy, and resistance. It is often difficult to ascertain whether an adverse effect is from the study drug or the natural progression of the disease. Further safety data are needed for the newer agents and for all agents with regard to patients with decompensated liver disease, renal dysfunction, the elderly, children, and pregnant women.

[Characteristics of hepatitis and influenza antivirals: update 2009]

This article aims to review hepatitis B and C and influenza infections and to summarise the main characteristics of the antiviral drugs available to treat those infections in adults. The review of each drug focuses on dosage depending on treatment indication, dosage adjustment in renal or hepatic impairment, main pharmacokinetic features and the most significant adverse effects and drug interactions.

Frequent hepatitis B virus rebound among HIV-hepatitis B virus-coinfected patients following antiretroviral therapy interruption

BACKGROUND

The impact of antiretroviral therapy (ART) interruption in HIV-hepatitis B virus (HBV)-coinfected patients was examined in the Strategic Management of AntiRetroviral Therapy (SMART) study.

METHODS

Plasma HBV DNA was measured in all hepatitis B surface antigen-positive (HBV-positive) participants at baseline, and at months 1, 2, 4, 6, 8, 10, and 12.

RESULTS

Among HBV-positive participants in the ART interruption (drug conservation) (n = 72) and ART continuation (virological suppression) (n = 62) arms, HBV DNA rebound of more than 1 log from baseline at months 1-4 was seen in 31-33% (P = 0.003) and 3-4% (P = 0.017), respectively. Thirteen HBV-positive participants had HBV DNA rebound of more than 3 log, including 12 in the drug conservation arm, of which eight were on tenofovir-containing regimens. Factors independently associated with a HBV DNA rebound were drug conservation arm (P = 0.0002), nondetectable HBV DNA at baseline (P = 0.007), and black race (P = 0.03). Time to ART reinitiation was shorter (7.5, 15.6, and 17.8 months; P < 0.0001) and proportion reinitiating greater (62.5, 46.5, and 39.7%; P = 0.0002) among HBV-positive participants as compared with hepatitis C virus-positive and non-HBV/hepatitis C virus participants in the drug conservation arm. No hepatic decompensation events occurred among HBV-positive participants in either arm.

CONCLUSION

HBV DNA rebound following ART interruption is common and may be associated with accelerated immune deficiency in HIV-HBV-coinfected patients.

Telbivudine exhibits no inhibitory activity against HIV-1 clinical isolates in vitro

Most approved drugs with activity against hepatitis B virus (HBV) have activity against human immunodeficiency virus type 1 (HIV-1), which precludes their use in patients who are coinfected with HBV and HIV-1 and who are not receiving antiretroviral therapy due to the risk of inducing resistance. The activity of telbivudine, a highly selective HBV inhibitor, against temporally and geographically distinct wild-type and multidrug-resistant HIV-1 clinical isolates was evaluated in vitro. No inhibition was observed with up to 600 muM drug, which supports further exploration of telbivudine as a therapeutic option for the treatment of HBV infections in patients coinfected with HIV-1.

HIV/hepatitis B virus co-infection: current challenges and new strategies

Chronic hepatitis B virus (HBV) infection, which affects 7%-10% of HIV-infected patients, is associated with an increased frequency of AIDS-related and non-AIDS-related clinical endpoints, such as end-stage liver diseases including cirrhosis and hepatocellular carcinoma. Broad access to a very efficient antiviral therapy containing nucleos(t)ide analogues with dual activity against HBV and HIV reverse transcriptases has initiated a transition in the paradigm of HBV control in the context of HIV-induced immunosuppression. The control of viral replication is not currently such a problem, but preventing the emergence of HBV polymerase and surface gene mutants after prolonged exposure to nucleos(t)ides and their consequences in terms of HBV vaccine escape are the next long-term challenges. Another challenge is the prevention of end-stage liver disease in an ageing population, in whom non-invasive markers of liver fibrosis, although used more frequently as a substitute for liver biopsy, are not the panacea. Finally, access to prevention, diagnosis, care and treatment of HBV infection remains a major issue in developing countries, including most regions of Africa and Asia, where HBV is endemic and the epidemic of HIV infection is still thriving.

Longitudinal evaluation of viral interactions in treated HIV-hepatitis B co-infected patients with additional hepatitis C and D virus

Virological interactions of hepatitis B (HBV), hepatitis C (HCV) and hepatitis D (HDV) viruses in HIV-infected patients have been poorly characterized especially under treatment influences. Undetection rates of hepatitis viruses were longitudinally analyzed in a 3-year cohort of 308 HIV-HBV co-infected patients and compared using Generalized Estimating Equation models adjusted for age, HIV-RNA, CD4 cell-count and antiviral treatment. Chronic hepatitis co-infection in HIV-infected patients (age years, SD) was: 265 HBV (40.7, 8.2); 19 HBV-HCV (39.7, 4.1); 12 HBV-HDV (35.2, 9.9); 12 HBV-HCV-HDV (39.2, 5.2). At inclusion, treatment with lamivudine/tenofovir was not significantly different between co-infection groups. HBV suppression was significantly associated with HDV (aOR = 3.85, 95%CI 1.13-13.10, P = 0.03) and HCV tri-infection (aOR = 2.65, 95%CI 1.03-6.81, P = 0.04), but marginally associated with HIV-HBV-HCV-HDV (aOR = 2.32, 95%CI 0.94-5.74, P = 0.07). In quad-infection, lower HDV-undetectability (vs HIV-HBV-HDV, P = 0.2) and higher HCV-undetectability (vs HIV-HBV-HCV, P = 0.1) were demonstrated. The degree of HBV suppression varied between visits and co-infection groups [range of aOR during follow-up (vs HIV-HBV co-infection): HIV-HBV-HCV = 2.23-5.67, HIV-HBV-HDV = 1.53-15.17]. In treated co-infected patients, HDV expressed continuous suppression over HCV- and HBV-replications. Peaks and rebounds from undetectable hepatitis B, C and/or D viremia warrant closer follow-up in this patient population. HDV-replication was uncontrolled even with antiviral treatment.

Telbivudine in the treatment of chronic hepatitis B: experience in HIV type-1-infected patients naive for antiretroviral therapy

BACKGROUND

Telbivudine is a potent inhibitor of hepatitis B virus (HBV) replication without anti-HIV type-1 (HIV-1) activity demonstrated in vitro; however, very few clinical data on HIV-1-infected patients are available at present. Because it represents a therapeutic option in HIV-1-HBV-coinfected patients who do not require antiretroviral therapy, we strictly monitored three HIV-1-HBV-coinfected patients treated with telbivudine monotherapy for chronic hepatitis B.

METHODS

We performed molecular analysis of HBV DNA and of HIV-1 reverse transcriptase and protease RNA and DNA sequences in three HIV-1-HBV-coinfected patients treated with telbivudine monotherapy.

RESULTS

Despite a transient and deep reduction of HIV-1 RNA, observed in two of the three patients studied, no genotypic resistance mutations were detected on both HIV-1 and HBV viruses.

CONCLUSIONS

Telbivudine therapy for 24 weeks showed a potent anti-HBV activity in HIV-1-positive, hepatitis B e antigen-positive patients with high HBV viraemia. No direct anti-HIV-1 activity of telbivudine was demonstrated and no genotypic resistance mutations to anti-HIV-1 drugs was found; however, the transient but deep reduction of HIV RNA, after telbivudine introduction, deserves further investigation and a strict monitoring of HIV-1 viraemia in HIV-1-infected patients on treatment with this drug.

HBV and HCV therapy

One year of interferon therapy inhibits HBV replication in one third of the patients whereas long-term administration of oral nucleos(t)ide analogues is efficient in most of them, as long as early treatment adaptation in patients with partial virological response and resistance is provided. Following the demonstration of a more potent antiviral effect in terms of sustained virological response (SVR) rates, Pegylated-IFN coupled with Ribavirin has become the standard treatment for chronic hepatitis C, with nearly 65% of all treated patients achieving a SVR. Long-term suppression of HBV and eradication of HCV would halt the progression of chronic hepatitis to cirrhosis, hepatocellular carcinoma and liver decompensation.

[Nucleoside and nucleotide analogs in the treatment of chronic hepatitis B]

At least 4 nucleos(t)ide analogs have been approved for the treatment of chronic hepatitis B: lamivudine, adefovir dipivoxil, entecavir, and telbivudine. The introduction of these drugs has radically changed the treatment of this disease. The advantages of these drugs are their oral administration, excellent tolerability and efficacy in all types of chronic hepatitis B (compensated and decompensated disease). The limitations are the need for prolonged treatments, which hampers adherence and can cause selection of HBV strains resistant to distinct drugs. The resistance rate differs for each of the drugs. Nucleotide analogs such as adefovir and tenofovir are useful in patients resistant to nucleoside analogs such as lamivudine, entecavir and telbivudine and vice versa. In cases of resistance to one of these drugs, combined treatment is advised.

[Hepatitis B in patients with HIV infection]

Chronic hepatitis B virus infection affects approximately 10% of HIV-infected patients. There are an estimated 4 million patients with HIV/HBV coinfection. HIV infection has a deleterious effect on the natural history of chronic hepatitis B and increases the risk of progression to cirrhosis and terminal liver disease. Since the widespread use of highly active antiviral therapy (HAART), liver disease has emerged as one of the main causes of morbidity and mortality in HIV-positive patients. Therefore, all patients with HIV/HBV coinfection should be evaluated for treatment of hepatitis B, independently of the CD4 lymphocyte count. Six drugs are currently authorized for the treatment of chronic hepatitis B: standard interferon-alpha (2a and 2b), pegylated interferon alpha-2a, lamivudine, adefovir, entecavir and telbivudine. Other drugs with activity against HBV, such as tenofovir and emtricitabine, are used for the treatment of HIV infection. In patients not requiring HAART, treatment of hepatitis B should preferably consist of drugs without activity against HIV, such as pegylated interferon or adefovir. In contrast, in patients requiring HAART, a combination of drugs with activity against both viruses should be used, such as lamivudine, emtricitabine and tenofovir, with the aim of achieving maximal viral suppression and avoiding the development of resistance. Patients with HIV/HBV coinfection require periodic clinical and virological monitoring. Patients with cirrhosis should undergo ultrasonography and alphafetoprotein determination every 6 months for the early detection of hepatocellular carcinoma.

[Treatment of chronic hepatitis B in HIV co-infected patients]

Because of complex interactions between HIV, hepatitis B virus (HBV), immune system and antiretrovirals, treatment of HBV infection in HIV population should consider both viruses. In co-infected patients with no indication of antiretrovirals, drugs with dual activity against HBV and HIV are not recommended to avoid development of HIV resistance (lamivudine, emtricitabine, entecavir, tenofovir disoproxil fumarate). Adefovir dipivoxil or pegylated interferon may be used. Telbivudine may have a role in combination with adefovir dipivoxil in this situation. In patients with an indication of antiretroviral therapy, regimens should include tenofovir in association with lamivudine or emtricitabine. In patients who had developed HBV lamivudine (or emtricitabine) resistance addition of tenofovir to antiretroviral regimen including maintenance of lamivudine or emtricitabine is the preferred choice.

Efficacy and safety of entecavir for chronic HBV in HIV/HBV coinfected patients receiving lamivudine as part of antiretroviral therapy

BACKGROUND

Prolonged use of lamivudine in patients coinfected with HIV and hepatitis B virus (HBV) leads to an increasing risk of lamivudine resistance in both diseases. We investigated the addition of entecavir, a potent inhibitor of HBV polymerase, to lamivudine-containing highly active antiretroviral therapy (HAART) in patients who experienced rebound in HBV viremia while maintaining suppression of plasma HIV RNA less than 400 copies/ml.

METHODS

Sixty-eight patients were randomized to entecavir 1 mg (n = 51) or placebo (n = 17) once daily for 24 weeks; 65 patients continued the study with entecavir for an additional 24 weeks. Lamivudine-containing HAART was continued throughout.

RESULTS

At week 24, the mean HBV DNA in entecavir-treated patients was 5.52 log10 copies/ml versus 9.27 log10 copies/ml for placebo, and at week 48, it was 4.79 log10 copies/ml versus 5.63 log10 copies/ml, respectively. The mean HBV DNA change from baseline for entecavir was -3.65 log10 copies/ml (versus + 0.11 for placebo, P < 0.0001) and alanine aminotransferase normalization in 34% of patients (versus 8% for placebo, P = 0.08). At 48 weeks, mean change in HBV DNA reached -4.20 log10 copies/ml in patients who received entecavir for the entire 48 weeks. The frequency of adverse events with entecavir and placebo was comparable. Through 48 weeks, no clinically relevant changes in HIV viremia or CD4 cell counts were identified.

CONCLUSION

In this study, entecavir was associated with rapid, clinically significant reductions in HBV DNA, with maintenance of HIV viremia suppression, in HIV/HBV coinfected patients with HBV viremia while on lamivudine treatment.

Treatment of chronic hepatitis B: recommendations from an Italian workshop

The changing scenario of hepatitis B virus therapy has encouraged the organisation of a workshop, endorsed by three Italian scientific societies, aimed at defining the current recommendations for hepatitis B virus treatment. Liver histology and stage of disease remain fundamental for treatment decisions; interferon and nucleoside/nucleotide analogues-based therapy represent different strategies for different phases of the hepatitis B virus disease. The recommendations defined: new and lower cut-off of hepatitis B virus-DNA for eligibility to therapy according to disease stage, how to optimise the use of nucleoside/nucleotide analogues and to individualise the monitoring of response and what to do with treatment failures. Specific recommendations have also been given for cirrhosis patients, those immune suppressed and co-infected with HIV and other hepatitis viruses.

Antiviral effects of lamivudine, emtricitabine, adefovir dipivoxil, and tenofovir disoproxil fumarate administered orally alone and in combination to woodchucks with chronic woodchuck hepatitis virus infection

Adefovir dipivoxil (ADV) and tenofovir disoproxil fumarate (TDF) are nucleotide analogs that inhibit the replication of wild-type hepatitis B virus (HBV) and lamivudine (3TC)-resistant virus in HBV-infected patients, including those who are coinfected with human immunodeficiency virus. The combination of ADV or TDF with other nucleoside analogs is a proposed strategy for managing antiviral drug resistance during the treatment of chronic HBV infection. The antiviral effect of oral ADV or TDF, alone or in combination with 3TC or emtricitabine (FTC), against chronic woodchuck hepatitis virus (WHV) infection was evaluated in a placebo-controlled study in the woodchuck, an established and predictive model for antiviral therapy. Once-daily treatment for 48 weeks with ADV plus 3TC or TDF plus FTC significantly reduced serum WHV viremia levels from the pretreatment level by 6.2 log(10) and 6.1 log(10) genome equivalents/ml serum, respectively, followed by TDF plus 3TC (5.6 log(10) genome equivalents/ml), ADV alone (4.8 log(10) genome equivalents/ml), ADV plus FTC (one survivor) (4.4 log(10) genome equivalents/ml), TDF alone (2.9 log(10) genome equivalents/ml), 3TC alone (2.7 log(10) genome equivalents/ml), and FTC alone (2.0 log(10) genome equivalents/ml). Individual woodchucks across all treatment groups also demonstrated pronounced declines in serum WHV surface antigen, characteristically accompanied by declines in hepatic WHV replication and the hepatic expression of WHV antigens. Most woodchucks had prompt recrudescence of WHV replication after drug withdrawal, but individual woodchucks across treatment groups had sustained effects. No signs of toxicity were observed for any of the drugs or drug combinations administered. In conclusion, the oral administration of 3TC, FTC, ADV, and TDF alone and in combination was safe and effective in the woodchuck model of HBV infection.

The use of molecular assays in the management of viral hepatitis

Molecular assays are instrumental in the clinical management of viral hepatitis. During the past years, a wide variety of molecular assays have been developed and implemented. This considerably improved the understanding of the natural history and pathogenesis of Hepatitis B virus (HBV), Hepatitis C virus (HCV) or Hepatitis delta virus (HDV) hepatitis, but also caused uncertainties in the selection of the most appropriate assays for clinical requirements. Indeed, a rational choice and application of these assays requires adequate knowledge of the performance of the single test. Moreover, the choice of the most accurate assay for patients' needs and physicians' objectives, needs to be oriented to specific contexts, such as diagnosis, management or treatment. In the past, a hurdle in the routine use of assays for hepatitis viruses nucleic acid quantification was represented by the availability of only "home brew" methods which lacked standardization. Major improvement in addressing the use of molecular assays for viral hepatitis has been derived from recent standardization procedures that allowed a comparison between different tests after results were given as International Units. In addition, it should be reminded that, before getting into the market, molecular assays should be approved by European regulation authorities and validated using internationally recognized standards. A subsequent clinical validation should address the diagnostic accuracy of the assay. These proceedings have the aim of identifying which molecular tests, among those currently available, meet clinical requirements for each specific application.

Early emergence of entecavir-resistant hepatitis B virus in a patient with hepatitis B virus/human immunodeficiency virus coinfection

The efficacy of entecavir for patients with hepatitis B virus/human immunodeficiency virus coinfection has not been fully elucidated. Here we examined a patient coinfected with both viruses in whom entecavir-resistant hepatitis B virus appeared. The 60-year-old Japanese male with the coinfection received antiretroviral therapy including lamivudine. The therapy initially suppressed replication of both viruses, followed by reactivation of the hepatitis B virus alone by 2 years of therapy. He subsequently received entecavir therapy in addition to the antiretroviral regimen. After entecavir administration, the hepatitis B virus DNA level was slightly reduced, but then increased after 6 months of entecavir therapy. In the sequencing analysis of hepatitis B virus, no drug resistance-associated amino acid substitutions were observed in the reverse transcriptase (rt) domain before antiretroviral therapy. The lamivudine-resistant amino acid substitutions at rt173, rt180 and rt204 were detected before entecavir administration, and further the entecavir-resistant rt202 substitution was observed after 6 months of entecavir therapy. The full-length hepatitis B sequences showed that the viral strain derived from the patient belonged to genotype H. In summary, this report describes a patient with hepatitis B virus/human immunodeficiency virus coinfection who received entecavir therapy in addition to an antiretroviral regimen and showed the early emergence of entecavir-resistance hepatitis B virus. In entecavir therapy for patients infected with both viruses, great care should be taken with respect to the emergence of entecavir-resistant hepatitis B virus, especially in patients with pre-existing lamivudine-resistant virus.

Understanding the pathogenesis and management of hepatitis B/HIV and hepatitis B/hepatitis C virus coinfection

The approach to the hepatitis B virus (HBV)-infected patient who is also infected with HIV or hepatitis C virus (HCV) is very different from the approach to the patient with only one virus infection. HBV/HIV coinfection is common. Agents that have dual activity against HBV and HIV should be considered as treatment of choice in combination regimens in HBV/HIV-coinfected patients beginning antiretroviral therapy. In HBV/HCV coinfection HCV usually tends to predominate over HBV. More investigation is needed into the mechanisms by which viral pathogenesis is altered and the optimal treatment modalities for coinfected patients.

Low resistance to adefovir combined with lamivudine: a 3-year study of 145 lamivudine-resistant hepatitis B patients

BACKGROUND & AIMS

Adefovir monotherapy is an established treatment modality for lamivudine-experienced patients with chronic hepatitis B, but it carries a significant risk of resistance in the long term. We assessed whether this risk could be overcome by adefovir-lamivudine combination therapy.

METHODS

A total of 145 lamivudine-resistant patients with chronic hepatitis B (73% cirrhotics, 86% hepatitis B e antigen negative, 92% genotype D) were treated with adefovir 10 mg in addition to lamivudine 100 mg. Liver function tests and hepatitis B virus (HBV) DNA (Versant 3.0) were assessed bimonthly, whereas adefovir-related mutations were searched by INNO-LiPA assay at baseline and at yearly intervals.

RESULTS

During 42 months (range, 12-74), 116 patients (80%) cleared serum HBV DNA, 67 (84%) had normalized alanine aminotransferase levels, and 145 (100%) remained free of virologic and clinical breakthroughs, independently of the degree of HBV suppression. The rtA181V/T was the only adefovir-related mutation detected, which occurred in 6 patients at baseline (4%; 1 rtA181V and 5 rtA181T) and in an additional 3 patients (2%; all rtA181T) during treatment. In all these 9 patients, HBV DNA levels progressively declined during therapy to become undetectable in 7 (78%). The 1-, 2-, 3-, and 4-year cumulative rates of de novo rtA181T were 1%, 2%, 4%, and 4%, respectively. None of the cirrhotic patients clinically decompensated, but 11 (12%) developed hepatocellular carcinoma.

CONCLUSIONS

Under prolonged adefovir-lamivudine therapy, patients with lamivudine-resistant hepatitis B were unlikely to develop genotypic resistance to adefovir and had durable prevention of virologic and clinical breakthrough.

Antiviral prophylaxis for chemotherapy-induced reactivation of chronic hepatitis B virus infection

Chronic hepatitis B virus (HBV) carriers are at considerable risk of reactivation of HBV infection when undergoing chemotherapy or immunosuppressive therapy. Complications of HBV reactivation, including asymptomatic elevation of HBV DNA levels, acute hepatitis, acute liver failure, and delays or dose reductions in chemotherapy, are avoidable with appropriate prophylactic oral antiviral therapy. This article reviews evidence for and presents a grade A recommendation supporting primary prophylaxis among HBV carriers with lamivudine. The dose and duration of prophylaxis, risk of lamivudine resistance, and future directions of prophylactic therapy for HBV reactivation during chemotherapy are discussed. Recommendations are suggested based on expert opinion for prophylaxis with the combination of lamivudine plus adefovir or with entecavir as alternative antiviral strategies that substantially reduce or avoid the risk of HBV antiviral drug resistance.

Safety and tolerability of sequential pegylated IFN-alpha2a and tenofovir for hepatitis B infection in HIV(+) individuals

Chronic hepatitis B virus infections are a major cause of morbidity and mortality in HIV co-infected patients. The standard of care for treating HCV co-infection has been guided by major clinical trials, but the treatment of HBV co-infection has not been as thoroughly studied and the standard of care remains largely untested. The single pill formulation of tenofovir with emtricitabine has become a standard treatment approach in HBV co-infected patients. WU114 was a phase 1 clinical trial that examined the safety and tolerability of sequential treatment of HBV with pegylated interferon-alpha2a plus delayed-initiation tenofovir in HIV co-infected individuals. We postulated that initial HBV viral load reduction with pegylated interferon prior to initiation of nucleoside/nucleotide therapy would increase seroconversion events and durability of HBV virologic suppression. No severe pegylated IFN-alpha2a drug toxicities were seen in either the monotherapy or delayed tenofovir arms. Sequential pegylated interferon and tenofovir-based therapy was tolerable and should be compared with dual nucleoside/nucleotide suppression to determine relative frequencies of seroconversion and durability of HBV suppression in co-infected patients.

Hepatitis B in the HIV-Coinfected Patient

HIV and hepatitis B virus (HBV) infection share transmission patterns and risk factors; therefore, it is not surprising that the prevalence of chronic HBV infection is elevated among HIV-infected persons. HBV does not significantly affect the course of HIV disease, but HIV does alter the course of HBV. HIV-infected persons are less likely to clear acute HBV infection spontaneously, and HIV/HBV-coinfected persons face a higher risk of liver-related death than those monoinfected with either virus. The immune restoration associated with highly active antiretroviral therapy (HAART) can improve control of HBV replication but can also lead to increased immune-mediated liver injury. On balance, use of HAART before severe immunosuppression develops may be beneficial. Still, the complexity of HBV, HIV, and HAART interactions must be evaluated for each individual. There is a dearth of high-quality evidence about management of coinfected patients. A recent consensus conference has issued recommendations. HBV DNA thresholds for starting anti-HBV therapy are the same in coinfected and HBV-monoinfected patients. Continuing drugs with anti-HBV activity is important, because stopping such therapy has been associated with HBV reactivation. Development of resistance is a risk with the long-term maintenance therapy required in most patients.

The management of HIV and hepatitis B coinfection

PURPOSE OF REVIEW

Coinfection with HIV and hepatitis B virus has a significant impact on the natural history of hepatitis B disease with faster rates of progression to cirrhosis and end stage liver disease. An increasing number of hepatitis B virus active drugs are now available, many of which have dual anti-HIV activity. This review highlights the most important recent developments in the management of HIV and hepatitis B virus coinfection.

RECENT FINDINGS

Natural history studies continue to confirm the increased rate of liver-related mortality in coinfected individuals and the importance of hepatocellular carcinoma in this population. The most recent studies of adefovir and tenofovir in open label use in coinfected individuals are discussed and new data on the activity of emtricitabine, entecavir and pegylated interferon are presented. Strategies for use of these new options for anti-hepatitis B virus therapy in coinfected individuals are discussed.

SUMMARY

Prevention of end stage liver disease and hepatocellular carcinoma in the coinfected population is vital and the increasing availability of drugs with potent anti-hepatitis B activity is encouraging. Appropriate diagnosis and monitoring of hepatitis B, coupled with better understanding of the mechanisms of drug resistance, will enable clinicians to manage coinfection more effectively.

The effects of HCV infection and management on health-related quality of life

Infection with HCV leads to an array of symptoms that compromise health-related quality of life (HRQL). Chronic hepatitis C is treated primarily with pegylated interferon (peg-IFN) and an inosine 5' monophosphate dehydrogenase inhibitor, ribavirin (RBV), with the goal of achieving a sustained virologic response (SVR). SVR reduces the rate of hepatic fibrosis and other disease-related complications and, in turn, increases HRQL. Although combination therapy with peg-IFN and RBV produces SVRs in more than 50% of treated patients, it is associated with side effects that can reduce short-term HRQL, can lead to dose reductions and discontinuations, and may impair treatment response. Fatigue and depression are common symptoms of chronic HCV infection that may also be caused by IFN-based therapy. Hemolytic anemia and IFN-mediated bone marrow suppression are well-known consequences of IFN/RBV therapy, often resulting in dose reductions or discontinuations, and have the potential to affect SVR rates. Management of these symptoms is vital to successful outcomes and generally relies on therapy that is adjunctive to the primary treatment of the viral infection itself. Several new drugs with the potential to increase SVR rates without compromising HRQL are in development.

CONCLUSION

The relationship of chronic HCV infection, treatment, and HRQL is complex. Successful treatment of chronic hepatitis C requires an understanding of the intricacies of this relationship and appropriate management of treatment-related symptoms.

Progress in the treatment of chronic hepatitis B: long-term experience with adefovir dipivoxil

Most chronic hepatitis B patients do not undergo a curative response to interferon-alpha or nucleoside/nucleotide-based regimens and require long-term therapy. Long-term safety, efficacy and resistance profiles of hepatitis B virus (HBV) drugs are therefore crucial issues for patient management. Adefovir dipivoxil is a nucleotide prodrug indicated for the treatment of patients with hepatitis B e antigen positive or hepatitis B e antigen negative chronic hepatitis B, lamivudine-resistant HBV infection, HBV infection pre- or post-liver transplantation, or HlV co-infection. Long-term data from clinical trials of up to 5 years duration of adefovir dipivoxil have recently become available and are reviewed here. These data demonstrate that adefovir dipivoxil therapy results in sustained efficacy and safety in the majority of patients after multiple years of treatment. The efficacy of adefovir dipivoxil in treating lamivudine-resistant HBV and the delayed emergence of adefovir resistance are key factors contributing to the durable response achieved in broad groups of chronic hepatitis B patients.

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.

A novel hepatitis B virus mutation with resistance to adefovir but not to tenofovir in an HIV-hepatitis B virus-co-infected patient

A molecular virology analysis performed in an HIV-hepatitis B virus (HBV) co-infected patient showed the emergence of an unusual HBV polymerase gene mutation (rt A181T) under adefovir therapy, conferring resistance to adefovir but not to tenofovir, as proved by in-vitro phenotypic analysis. This observation suggests that careful monitoring of co-infected patients is required to diagnose HBV resistance to nucleos(t)ide analogues, and that tenofovir may be active at least against some of the adefovir-resistant strains.

Treatment of chronic hepatitis B: efficacy of current drugs and prospects for the future

Chronic hepatitis B is an important clinical problem often leading to severe complications. In this review, the results obtained in the last few years with the use of current drugs, such as interferon and nucleo(t)side analogues, are summarized and the problems of obtaining a sustained remission, which is only achieved in a small number of patients, are discussed. The new approaches, such as the use of combinations of drugs, to optimize long-term tolerable treatment are also considered.

Chinese medicine Jiangganlong combined with anti-virus medicine in long-term treatment of active liver cirrhosis and its effect on prognosis of patients

AIM: To study the efficacy of Chinese medicine Jiangganlong combined with anti-virus medicine in the treatment of active liver cirrhosis (ALC).

METHODS: A total of 114 ALC patients were divided into treatment group and control group, named A and B, respectively. The patients in group A were treated with Jiangganlong and lamivudine (LAM). Jiangganlong decoction or pills were given a dose every three days, or 4.0 g (tid). LAM was administered 0.1 g per day. After the emergence of YMDD variations, adefovir (ADV) was added. LAM was stopped when HBV DNA YMDD variation became negative. The patients in group B received general and symptomatic treatment. The mean treatment therapeutic time was 36 months.

RESULTS: The rates of negative conversion for the serum HBV DNA were 75.4% (43/57) and 3.5% (2/57) in group A and B, respectively, and there was significant difference between them (P < 0.01). The cumulative rate of YMDD variations among patients of group A was 40.4% (23/57). After the emergence of YMDD variations, 20 patients received ADV treatment, 90% (18/20) of which were found YMDD variation-negative; there were 3 patients who did not receive ADV treatment, and they died of liver failure. The negative conversion rates of HBeAg were 44.4% (16/36), 16.7% (5/30) in group A, B, respectively, and there was marked difference between them (P < 0.05). The total bilirubin (TBIL) and alanine aminotransferase (ALT) returned to the normal level, and the albumin level, Child-Pugh score, and decompensation status were improved in group A. The rate of complications was dramatically lower in group A than that in group B [14.0% (8/57) vs 50.8% (29/57), P < 0.01]. The mortality rate was also decreased in group A as compared with that in group B [7.0% (4/57) vs 29.8% (17/57), P < 0.01], while the survival time was notably prolonged (3.3 ± 2.1 year vs 1.1 ± 1.0 year, P < 0.01).

CONCLUSION: Chinese medicine Jiangganlong combined with anti-virus medicine can inhibit the replication of HBV DNA, ameliorate liver function, decrease the rate of complications, reduce the mortality rate, and prolong the survival time as well as improve the prognosis of ALC patients.

Systematic review: lamivudine prophylaxis for chemotherapy-induced reactivation of chronic hepatitis B virus infection

BACKGROUND

Reactivation of hepatitis B virus infection in asymptomatic hepatitis B surface antigen carriers undergoing chemotherapy or immunosuppressive therapy is a well-documented and potentially fatal complication. Data supporting the use of lamivudine for primary prophylaxis have emerged, but its use remains controversial and is not standardized.

AIM

To review current randomized-controlled trials, randomized trials and prospective case series to provide a clinically applicable, evidence-based recommendation.

METHODS

The published literature was identified using a MEDLINE/PubMed search with secondary review of cited publications, and inclusion of all prospective studies.

RESULTS

In nine prospective trials and one randomized-controlled trial, the rate of hepatitis among subjects receiving lamivudine prophylaxis ranged from 0% to 20% (16 of 173, 9.2%), compared with 33-67% among controls. Of patients receiving prophylaxis, 0-24% (15 of 173, 8.7%) developed hepatitis B virus reactivation, compared with 29-56% of controls. Three reactivation-related mortalities were reported (one receiving prophylaxis, two controls). No patients withdrew secondary to toxicity or development of lamivudine-resistant mutations.

CONCLUSIONS

The available data show a four- to sevenfold decrease in the rate of hepatitis and hepatitis B virus reactivation in patients who receive lamivudine prophylaxis. It is thus recommended that all hepatitis B surface antigen carriers receive lamivudine, or a comparable anti-viral agent, as prophylaxis from the initiation of chemotherapy until at least 1 year following its completion.