Tenofovir disoproxil fumarate versus adefovir dipivoxil for chronic hepatitis B

Consequences of persistent HBV infection in HIV: the double-edged sword of nucleos(t)ide analogs

A variety of nucleos(t)ide analogs (NA) are available to treat HBV infection, the majority of which are also active against HIV, and when alone or in combination, have proven to actively suppress circulating HBV. However during treatment, especially among HIV-infected patients, the persistent nature of replicating intracellular DNA and lack of HBsAg loss indicates the potential for NA resistance and hence changes in HBV genetic variability. Meanwhile, cytotoxic CD8+ T cells responsible for clearing infected hepatocytes appear to become exhausted and anti-HBV immunoglobulin-producing B cells become deficient; both of which can be altered during HIV infection. Furthermore, host-determinants, specifically regulation of HBV integration into the host genome and polymorphisms on the HLA allele, have been shown to affect HBV replication. Studies on how these selective pressures influence HBV genetic variability are sparse, yet lead to important considerations on NA resistance during persistent infection.

HBV DNA suppression in HBeAg-positive chronic hepatitis B patients treated with peginterferon or placebo

The aim of the present study was to compare the decline of HBV DNA during peginterferon (PEG-IFN) therapy with spontaneous HBV DNA decline in placebo-treated patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B. A total of 136 patients who participated in a randomized trial were treated with PEG-IFN alfa-2b for 52 weeks. These patients were compared with 167 patients who received a placebo for 48 weeks using linear mixed regression analysis. Response was defined as loss of HBeAg at the end of treatment (EOT). Overall, decline of HBV DNA at the EOT was significantly greater in the PEG-IFN group than in the placebo group (mean decline 2.3 log vs. 1.0 log, P < 0.001) and varied according to HBV genotype. Viral suppression was greater in the PEG-IFN group from week 4 throughout the entire treatment period (P < 0.001). The response rate was 32% for the PEG-IFN group and 11% for the placebo group (P < 0.001). Among responders, HBV DNA decline was greater for patients treated with PEG-IFN than with a placebo: the mean difference in HBV DNA decline was 0.7 log (P = 0.001) at 4 weeks and 2 log (P < 0.001) at the EOT. ALT flares (>5 times the upper limit) were associated with a greater HBV DNA decline during PEG-IFN. In conclusion, PEG-IFN therapy resulted in a greater HBV DNA decline in positive HBeAg patients than a placebo. The decline of HBV DNA was greater in patients with HBeAg loss or who exhibited an ALT flare during PEG-IFN than in patients with spontaneous HBeAg loss or flares during placebo therapy.

Rescue therapy for lamivudine-resistant chronic hepatitis B: adefovir monotherapy, adefovir plus lamivudine or entecavir combination therapy

OBJECTIVE

We aimed to compare the cumulative efficacy and resistance of ADV monotherapy, ADV add-on LAM (ADV + LAM), ADV and ETV (ADV + ETV) combination therapy in LAM-resistant patients.

METHODS

Ninety-one adult CHB patients with LAM-resistance mutations (YMDD) were identified. Of these 91, 29 patients were treated with ADV monotherapy, 30 were treated with ADV + LAM and 32 were treated with ADV + ETV combination therapy, for at least 24 months.

RESULTS

The mean serum HBV-DNA decreases from baseline at 3, 6, 12, and 24 months were -3.23, -4.41, -5.32, and -5.58 log(10) IU/mL in the ADV + ETV combination therapy groups, respectively; the most significant among the three treatment groups (p<0.01). The rate of HBV-DNA PCR undetectability (<60 IU/mL) at 6 months in ADV + ETV combination therapy was 78.1%; also the most significant among the three treatment groups (p=0.024). Viral breakthrough and genotypic mutations were detected in 8 (27.6%) and 4 (13.3%) patients in the ADV monotherapy and ADV+LAM therapy groups, respectively; whereas no case of viral breakthrough and genotypic resistance was detected in the ADV+ETV combination therapy group after 24 months (p<0.05).

CONCLUSION

ADV + ETV combination therapy demonstrated faster and significantly greater suppression of HBV DNA compared with ADV add-on LAM combination therapy for patients with LAM-resistance mutations. ADV + ETV was superior to ADV + LAM in achieving initial virological response and long-term suppression activity against HBV. ADV + ETV combination therapy was the most effective to refrain from selecting HBV strains with cross-resistance to three NAs (LAM, ADV and ETV) for LAM-resistance patients.

Laboratory evaluation of three regimens of treatment of chronic hepatitis B: tenofovir, entecavir and combination of lamivudine and adefovir

BACKGROUND

Chronic hepatitis B is a disease of concern due to its life-threatening complications like cirrhosis, and hepatocellular carcinoma (HCC) in 20-40% of patients. There are about 400 million people affected worldwide with HBV, and over 300,000 die every year from HBV-related diseases. Oral antivirals like lamivudine, adefovir, entecavir, and tenofovir are commonly used to treat chronic hepatitis B. In this study, we tried to evaluate the comparative efficacy of these drugs alone and in combination.

MATERIALS AND METHODS

Chronic hepatitis B patients with HBV-DNA more than 10⁴Copies/mL irrespective of their HBeAg status (n=60) were enrolled in a prospective study. 21, 20, and 19 patients were treated with lamivudine (100 mg/day) plus adefovir (10 mg/day) combination entecavir monotherapy (0.5 mg/day) and tenofovir monotherapy (300 mg/day), respectively and were followed up for 24 weeks with their virological, serological, and biochemical markers measured at 12 and 24 weeks.

RESULTS

After 24 weeks of treatment, there was no significant difference between the 3 groups in suppressing HBV-DNA to undetectable levels. The median decrease in HBV-DNA levels from baseline was better with tenofovir and entecavir monotherapies than lamivudine and adefovir combination, which was statistically significant. There was no significant difference between the 3 groups in HBsAg and HBeAg seroconversion and normalization of biochemical parameters.

CONCLUSION

Entecavir and tenofovir monotherapy were found to be more effective than lamivudine plus adefovir combination in reducing the HBV-DNA levels. However, lamivudine plus adefovir combination was not too inferior, especially when cost of treatment was taken into consideration.

Long-term outcome of primary non-responders to tenofovir therapy in HIV/HBV-co-infected patients: impact of HBV genotype G

AIM

To evaluate the early virological response (EVR) to combined tenofovir-lamivudine or emtricitabine regimen in HBV/HIV-co-infected patients and the long-term efficacy of tenofovir.

METHODS

In this retrospective monocentric study, among the 166 HIV/HBV-co-infected patients regularly followed from 2003 to 2008 at Bichat Claude Bernard Hospital, 61 patients had received, either de novo combination therapy with tenofovir and lamivudine or emtricitabine (group I, n = 15) or add-on tenofovir to lamivudine therapy (group II, n = 46). The HBV polymerase region was sequenced and analysed for all patients with available samples.

RESULTS

All 15 group I patients achieved EVR vs 32 (82%) of group II patients (P = 0.15). Seven adherent group II patients met criteria for primary non-response, but achieved delayed response (DR) to therapy. In these seven patients, when compared with the 39 group II patients, there was a trend to longer duration of lamivudine pre-treatment and to higher rate of lamivudine-resistant mutants; and HBV genotype-G proportion was higher (P = 0.026). No virological breakthrough occurred after a median of 46 months follow up.

CONCLUSION

In these HBV/HIV-co-infected patients, first-line HBV therapy with tenofovir and emtricitabine or lamivudine was associated with EVR. However, DR to tenofovir was observed in 15% of patients who added tenofovir to lamivudine therapy, of whom four of seven (57%) had genotype G-HBV infection. No resistance was evidenced after 46 months of therapy even in patients with DR to tenofovir. At last, a good renal safety profile of TDF was observed after a median follow-up of 4 years of therapy.

A review of chronic hepatitis B epidemiology and management issues in selected countries in the Middle East

Experts from seven countries convened as a Specialist Panel for the Middle East to share information on practical issues relating to the epidemiology, diagnosis and management of chronic hepatitis B (CHB) infection. The Middle East is regarded as a region of high-to-intermediate epidemicity; however, infant vaccination programmes have successfully lowered the prevalence of hepatitis B infection in most countries to that of low-to-intermediate endemicity. Vaccine issues still to be addressed included improving coverage in some rural/poor communities, instituting hepatitis B vaccine at birth and providing vaccines for high-risk population groups. Hepatitis B infection in the Middle East primarily occurs as a result of perinatal infection, horizontal transmission between family members and transmission from injections. Blood transfusion services have broadly efficient screening programmes, but immunocompromised and haemodialysis patients are at risk. The cost of screening, monitoring and treating CHB influences practice in a number of Middle East countries, and there is a need for information on the most cost-effective options.

Effect of HBV polymerase inhibitors on renal function in patients with chronic hepatitis B

BACKGROUND & AIMS

Therapy of chronic hepatitis B with HBV-polymerase inhibitors, in particular tenofovir or adefovir, may affect renal function. To assess renal function more accurately in the normal range, we used the recently validated, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula to calculate the estimated glomerular filtration rate (eGFR).

METHODS

Patient subgroups included: patients with HBV-monoinfection treated with lamivudine (n=36), adefovir (n=32), entecavir (n=32), or tenofovir (n=37). HBsAg-positive untreated patients (n=60) served as control. For comparison HIV-monoinfected patients treated with tenofovir (n=120) or zidovudine (n=52) based antiretroviral therapy and antiretroviral naive patients (n=109) were assessed. CKD-EPI equation was used to calculate eGFR. In a more sensitive approach, we modeled the individual change in eGFR over time with linear mixed effects models (LME).

RESULTS

Yearly predicted median changes in individual eGFR according to the LME model were: HBV untreated -2.05 ml/min, HBV lamivudine -0.92 ml/min, HBV adefovir -1.02 ml/min, HBV entecavir -1.00 ml/min, and HBV tenofovir -0.92 ml/min (p<0.01 for HBV untreated vs. HBV treated). In HIV-monoinfected patients: HIV untreated -0.62 ml/min, HIV treated with tenofovir -2.64 ml/min, HIV treated with zidovudine -1.0 ml/min (p=0.017 for tenofovir vs. no treatment, p<0.001 for tenofovir vs. zidovudine).

CONCLUSIONS

Therapy of HBV infection irrespective of medication seems to result in a milder decrease of renal function. In contrast tenofovir as part of HIV combination therapy seems to impair renal function in this Caucasian population.

Current Antiviral Therapy of Chronic Hepatitis B: Efficacy and Safety

The treatment of chronic hepatitis B is in constant evolution. Interferon, the first agent licensed for chronic hepatitis B treatment, has been superseded by the growing popularity of nucleoside/nucleotide analogues (NA). However, resistance to these agents is a major challenge. Newer NAs, such as entecavir and tenofovir dipivoxil fumarate, have very low resistance rates and favorable safety profiles. Long-term use of these agents can effectively suppress hepatitis B virus DNA, leading to decrease in incidence of hepatitic flares, as well as in the development of cirrhosis and hepatocellular carcinoma. The efficacy and safety of various antiviral agents is discussed in this review.

Review article: current antiviral therapy of chronic hepatitis B

BACKGROUND

The indications and endpoints for treatment of chronic hepatitis B continue to evolve. The aim of the therapy for chronic hepatitis B is to achieve a long-term continued suppression of the hepatitis B virus (HBV) DNA to prevent disease progression leading to the development of cirrhosis and hepatocellular carcinoma.

AIM

To summarise current literature on therapy of chronic hepatitis B, with a focus on indications for therapy, preferred treatment options, and management of resistance and partial responders.

METHODS

A systematic review of the literature, with a focus on international guidelines, was performed.

RESULTS

Seven drugs are licensed for the treatment of chronic hepatitis B in many countries. The selection of a drug with high potency and low rate of resistance is essential to achieve rapid and long-term viral suppression. The prevention of the sequelae of antiviral drug resistance and appropriate management of viral breakthrough are major goals of current management. The addition or change to an antiviral agent that is not cross-resistant is critical to restore suppression of viral replication for patients with breakthrough resistance. Patient adherence to medication is essential to achieve adequate HBV DNA suppression.

CONCLUSIONS

The current treatment strategy of chronic hepatitis B is now standard: initial selection of entecavir, tenofovir, or peginterferon alfa-2a. Future studies are required to determine if combination therapy using two oral agents or peginterferon with an oral agent with a high genetic barrier to resistance might be superior to standard current monotherapy.

Impact of hepatitis B e antigen-suppressing mutations on the replication efficiency of entecavir-resistant hepatitis B virus strains

Hepatitis B e antigen (HBeAg)-negative hepatitis B commonly requires long-term treatment with nucleos(t)ide analogues aiming at persistently suppressing hepatitis B virus (HBV) replication to halt progression of liver disease and prevent complications. Entecavir (ETV) is widely used in HBeAg-negative hepatitis B, but distinct HBV polymerase mutations can confer resistance against ETV, in conjunction with lamivudine resistance. Precore (PC) and basal core promoter (BCP) mutations that underlie HBeAg-negativity enhance replication of lamivudine-resistant mutants. To comprehensively analyse the impact of PC or BCP mutations on viral replication of ETV-resistant HBV mutants, replication-competent HBV constructs were generated harbouring lamivudine resistance (rtM204V/rtL180M, rtM204I) plus ETV resistance (rtS202G, rtS202I or rtT184G) on wild-type (WT)-, PC- and BCP-backgrounds. Functional consequences on viral fitness and susceptibility to antivirals were assessed in vitro. The presence of any ETV resistance drastically reduced viral replication when compared to WT HBV. In rtS202G mutants (plus lamivudine resistance), addition of either PC or BCP mutations moderately enhanced the reduced replication, without reaching WT HBV levels. In rtS202I or rtT184G mutants, PC and BCP mutations did not significantly improve viral fitness. All ETV-resistant constructs, independently of PC or BCP mutations, showed resistance towards ETV and lamivudine, but remained susceptible to tenofovir. Our data demonstrate that HBeAg-suppressing PC or BCP mutations cannot restore the strongly reduced replicative capacity of ETV-resistant HBV mutants to WT level, although they moderately increase replication of rtS202G combination mutants. ETV resistance thereby differs from lamivudine resistance alone, corroborating that ETV is in short term a safe option for HBeAg-negative patients.

High rate of complete viral suppression with combination therapy in patients with chronic hepatitis B and prior treatment failure

BACKGROUND

Combination therapy for chronic hepatitis B virus (HBV) infection is recommended for patients with antiviral resistance (AVR) or partial response (PR) to earlier antiviral therapy; however, data on outcomes are limited.

GOALS

To determine the rate of complete viral suppression (CVS) with combination therapy and to compare CVS among different indications and treatment regimens.

METHODS

A cohort of 109 consecutive patients with chronic hepatitis B from 3 liver clinics in Northern California was retrospectively studied. All patients started combination therapy between April 2004 and August 2009 for the following indications: AVR (n = 29), PR (n = 60), or others (n = 20). Combination treatments included lamivudine (LAM), adefovir (ADV), telbivudine (LdT), entecavir (ETV), tenofovir (TDF), and emtricitabine (FTC). CVS was defined as undetectable serum HBV DNA <100 IU/mL.

RESULTS

Among the patients, who were nearly all Asian (99%), 73% had ≥ 2 prior treatments and 82% had treatment failure (AVR or PR). Median treatment duration of combination therapy was 21 months (range, 6 to 50 mo). The majority (77%) achieved CVS after 6 months of various combination regimens: 80% for ETV+TDF, 76% for TDF+LAM or FTC or LdT, 75% for ETV+ADV, and 69% for ADV+LAM or LdT (P = 0.86). After 6 months of therapy, CVS was observed in a similar proportion of patients treated for PR and AVR (72% and 74%, respectively).

CONCLUSIONS

Although the majority of 109 treatment-experienced patients had prior treatment failure, high rates of CVS were rapidly achieved and did not significantly differ between indications of AVR and PR or between ETV-based and TDF-based regimens.

Partial virological response to entecavir in treatment-naive patients with chronic hepatitis B

BACKGROUND

The proposed definition of a partial virological response (PVR) to nucleos(t)ide analogue therapy in the 2009 European Association for the Study of the Liver (EASL) guidelines is based on limited evidence, especially in terms of the cutoff HBV DNA level and the time point at which to judge it. This study assessed optimal PVR criteria for predicting virological response (VR) at week 96 in treatment-naive patients with chronic hepatitis B (CHB) receiving entecavir (ETV).

METHODS

A total of 175 patients (126 men, 49 women) who completed 96 weeks of first-line ETV therapy were prospectively recruited. For predicting VR at week 96, the area under the receiver operating characteristic curve (AUC) was used to find the optimal time point and the Youden index was used to calculate the optimal cutoff HBV DNA level.

RESULTS

After 96 weeks of ETV therapy, 139 (79.4%) patients achieved VR. The AUC at week 48 was significantly better than that at week 24 for predicting VR at week 96 (P=0.023). The optimal cutoff HBV DNA level at week 48 was 35 IU/ml. Forty-one (23.4%) patients met this PVR criteria of ETV (HBV DNA level >35 IU/ml at week 48).

CONCLUSIONS

An HBV DNA level >35 IU/ml at week 48 is the optimal PVR criteria for predicting non-VR at week 96 in treatment-naive patients with CHB who are receiving ETV. This study supports the proposed EASL PVR for ETV based on scientific evidence.

Nucleoside/nucleotide analogues in the treatment of chronic hepatitis B

The current available agents for the treatment of chronic hepatitis B (CHB) include immunomodulatory agents, such as interferon-α and pegylated interferon-α, and oral nucleoside/nucleotide analogues (NAs), including lamivudine, adefovir, telbivudine, entecavir and tenofovir. The NAs work mainly by inhibiting hepatitis B virus (HBV) DNA polymerase activity and thus suppress HBV replication. Oral NAs have become the mainstay of CHB treatment, mainly due to their profound viral suppressive effects and also due in part to the ease of single daily dosing and lack of significant side effects. One major drawback of NA therapy is the development of drug resistance mutations with long-term treatment. Lamivudine, the first oral NA approved for CHB patients, is associated with high rates of drug resistance, with resultant virological relapse and biochemical flare. Fortunately, newer and more potent NAs, such as entecavir and tenofovir, have very low resistance rates, with potent and durable viral suppression. This review is aimed at the current developments in NAs for CHB treatment, detailing the mechanisms of antiviral activity of the different agents, the efficacy of viral suppression, the achievement of treatment endpoints, the development of drug resistance and the optimal strategies for using these drugs.

Chronic hepatitis B in pregnancy: unique challenges and opportunities

Chronic hepatitis B (CHB) affects 350 million individuals worldwide. Perinatal transmission leads to high rates of chronic infection and complications, including cirrhosis and hepatocellular carcinoma. It is important to recognize and appropriately treat CHB in pregnancy, thereby reducing the risk of neonatal transmission and HBV-associated morbidity and mortality. Screening for CHB is recommended in all pregnant mothers as is universal vaccination of infants with hepatitis B virus (HBV) vaccine with or without hepatitis B immunoglobulin (HBIG). This has resulted in a lower incidence of HBsAg seropositivity and HCC in regions where universal infant vaccination has been endorsed. Mode of delivery and breastfeeding do not appear to affect HBV transmission rates based on available data. Overall, CHB does not increase perinatal maternal-fetal mortality. Administration of oral antiviral therapy during the third trimester to HBsAg-positive mothers with HBV DNA≥7 log IU/mL may be useful in preventing breakthrough infection. Treatment may be considered earlier in pregnancy for persistently active liver disease shown by high ALT, HBV DNA levels and/or significant hepatic fibrosis. Lamivudine, tenofovir and telbivudine are safe and effective and are the agents of choice in pregnancy. However, further clinical studies are necessary to elucidate the role of antiviral therapy in the pregnant HBV carrier.

Cost effectiveness of screening immigrants for hepatitis B

BACKGROUND

The prevalence of chronic hepatitis B (CHB) infection among the immigrants of North America ranges from 2 to 15%, among whom 40% develop advanced liver disease. Screening for hepatitis B surface antigen is not recommended for immigrants.

AIMS

The objective of this study is to estimate the health and economic effects of screening strategies for CHB among immigrants.

METHODS

We used the Markov model to examine the cost-effectiveness of three screening strategies: (i) 'No screening'; (ii) 'Screen and Treat' and (iii) 'Screen, Treat and Vaccinate' for 20-65 years old individuals who were born abroad but are currently living in Canada. Model data were obtained from the published literature. We measured predicted hepatitis B virus (HBV)-related deaths, costs (2008 Canadian Dollars), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER).

RESULTS

Our results show that screening all immigrants will prevent 59 HBV-related deaths per 10, 000 persons screened over the lifetime of the cohort. Screening was associated with an increase in quality-adjusted life expectancy (0.024 QALYs) and cost ($1665) per person with an ICER of $69, 209/QALY gained compared with 'No screening'. The 'Screen, Treat and Vaccinate' costs an additional $81, generates an additional 0.000022 QALYs per person, with an ICER of $3, 648,123/QALY compared with the 'Screen and Treat'. Sensitivity analyses suggested that the 'Screen and Treat' is likely to be moderately cost-effective.

CONCLUSION

We show that a selective hepatitis B screening programme targeted at all immigrants in Canada is likely to be moderately cost-effective. Identification of silent CHB infection with the offer of treatment when appropriate can extend the lives of immigrants at reasonable cost.

Hepatitis B: modern end points of treatment and the specter of viral resistance

The goal of antiviral treatment of chronic hepatitis B is to prevent the complications of cirrhosis, hepatic decompensation, HCC, and death. Because these clinical outcomes may take a long period of time to develop, it is important to use intermediate or surrogate end points to evaluate the efficacy and response to antiviral treatment, and to determine whether treatment can be safely stopped, especially given concern for the development of antiviral resistance with NUC therapy. Although normalization of ALT and suppression of HBV DNA viral replication are associated with favorable outcomes, the durability of their response is low, and these end points are insufficient markers for stopping treatment. HBeAg seroconversion is currently used to discontinue NUC treatment in patients with HBeAg-positive chronic hepatitis B, whereas the stopping rule for HBeAg-negative disease relies on HBsAg loss. However, HBsAg loss occurs very infrequently and is not a practical end point for clinical use, although quantitative HBsAg levels may be useful in identifying patients who could achieve a sustained virologic response to treatment.

Molecular epidemiology of hepatitis B virus

Although safe and effective vaccines for hepatitis B virus (HBV) have been available for nearly three decades, this virus kills at least 600,000 people annually worldwide and remains the leading global cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Because the HBV reverse transcriptase lacks a proofreading function, many HBV genotypes, subgenotypes, mutants, and recombinants exist. At least 10 HBV genotypes (HBV-A through J) with distinct geographic distributions have been identified; by definition, their complete genomic sequences diverge by more than 8%. HBV genotype is increasingly becoming recognized as an important factor in the progression and clinical outcome of HBV-induced disease. Infections by HBV-C or -D are significantly more likely to lead to cirrhosis and hepatocellular carcinoma than are infections by HBV-A or -B. Additionally, the hepatitis B e antigen seroconversion response to standard or pegylated interferon is more favorable in patients with HBV-A or -B than in those with HBV-C or -D. However, therapeutic responses to nucleos(t)ide analogues are generally comparable among HBV genotypes. In conclusion, genotyping of HBV is useful in identifying chronic hepatitis B patients who are at increased risk of disease progression, thereby enabling physicians to optimize antiviral therapy for these patients.

Current Nucleos(t)ide Analogue Therapy for Chronic Hepatitis B

Although the prevalence of chronic hepatitis B has decreased considerably in recent years due to widespread use of the hepatitis B virus (HBV) vaccine, its prevalence still remains high in adults, and this can place a significant burden on health care in areas with endemic HBV. Since the introduction of nucleos(t)ide analogues (NUCs), there has been marked improvement in the care of patients with chronic hepatitis B, resulting in increased survival. However, the emergence of drug resistance in patients treated with NUCs is a major concern. The number of multi-drug resistant patients is increasing, and many patients may not respond to the currently available drugs. In this review, we describe the current status of NUC therapy for antiviral-naïve and -resistant patients.

Management of HIV and hepatitis virus coinfection

IMPORTANCE OF THE FIELD

Liver disease related to infection with hepatitis C virus (HCV) and/or hepatitis B virus (HBV) is a frequent cause of morbidity and mortality in those infected with the human immunodeficiency virus (HIV) in this era of highly active antiretroviral therapy (HAART). Although progress has been made in the treatment of HBV and HCV in the setting of HIV-coinfection, there is a lack of data in certain areas and several aspects of the management are unclear at this time.

AREAS COVERED IN THIS REVIEW

Available data on the treatment of HBV and HCV infections, especially in the HIV-coinfected patient, are presented. Practical aspects of the management of these patients are reviewed, including diagnosis, treatment indications, monitoring, and toxicities. The impact of HAART on liver disease, end-stage-liver disease, and new therapeutic approaches are also reviewed.

WHAT THE READER WILL GAIN

There are two modalities for the treatment of chronic HBV infection: interferon and nucleos(t)ide reverse transcriptase inhibitors (NRTI). The latter is the mainstream of therapy for HIV-HBV-coinfected patients. The double antiviral activity of NRTI requires coordination and careful selection of treatment for both viruses to avoid selection of resistance mutations and toxicity. Combination of pegylated interferon and ribavirin, the current standard treatment for chronic hepatitis C, has significant toxicity and limited efficacy in HIV-HCV-coinfected individuals. Oral anti-HCV treatments are currently under development and need to be studied in the HIV-coinfected population. Liver transplantation has a better outcome in HBV- than in HCV-HIV-coinfected patients. HAART seems to have a positive impact on the liver disease of HBV- and/or HCV-coinfected subjects but the CD4 threshold above which the benefit might take place is unknown at this time.

TAKE HOME MESSAGE

Anti-HBV treatment in the HIV-coinfected patient relies on the available NRTIs with activity against both viruses. Whereas HBV suppression can be achieved with this approach, toxicities and the selection of HBV-resistant variants result in challenging clinical scenarios. Current anti-HCV treatment (pegylated interferon and ribavirin) has limited efficacy in the HIV-coinfected patient, and STAT-C drugs are eagerly awaited.

Recent advances in the management of chronic hepatitis B

There are seven approved treatments for adults with chronic hepatitis B virus infection in the United States and European countries: interferon-α, pegylated interferon-α, lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate. At present, two new analogues, entecavir and tenofovir are recommended as the first line therapy by the guidelines of European Association for the Study of the Liver and American Association Study for the Liver Diseases. On the other hand, regarding interferon therapy, use of pegylated interferon-α is recommended as the first line therapy instead of standard interferon-α by both guidelines. Therefore, the main scientific interests and unmet medical needs for treatment of chronic hepatitis B have been narrowed down to long-term efficacy and safety of the two said analogues-entecavir and tenofovir-and combination therapy of pegylated interferon-α with the two analogues. To put it concretely, further studies are needed to assess (1) the long-term efficacy and safety and resistance to entecavir and tenofovir; (2) the efficacy of different durations (24 weeks to 2 years) and lower doses of pegylated interferon-α; (3) the role of combination therapy with two analogues to reduce resistance; and (4) the efficacy and safety of the two analogues with decompensated cirrhosis. Herein, we review the recent available data and results.

Sequential therapy with adefovir dipivoxil and pegylated interferon alfa-2a for HBeAg-negative patients

To assess the impact of sequential therapy with adefovir dipivoxil (ADV) and pegylated interferon alfa-2a (PEG-IFN) on virological (serum HBV-DNA) and serological (serum HBsAg) response in 20 consecutive HBeAg-negative patients. Patients received ADV for 20 weeks, then ADV and PEG-IFN for 4 weeks and lastly PEG-IFN for 44 weeks. Serum HBV-DNA and HBsAg were assessed at baseline, during therapy (weeks 20, 44 and 68) and follow-up (weeks 92 and 116). Sustained virological response (SVR) was defined as serum HBV-DNA <10 000 copies/mL (partial) or <70 copies/mL (complete) 24 weeks after stopping treatment. A serological response was defined as a serum HBsAg decrease ≥1 log(10) IU/mL at the end of treatment. Baseline median serum HBV-DNA and HBsAg levels were 7.6 log(10) copies/mL and 3.8 log(10) IU/mL, respectively. Ten patients (50%) achieved SVR, six of them had partial response and four complete response. Four patients (20%) achieved serological response. Complete SVRs showed a major and steep decline in HBsAg level with a median decrease of 0.5, 1.6 and 2.0 log(10) IU/mL at treatment week 20, 44 and 68, respectively. Partial SVRs showed a slight and slow decline in serum HBsAg level (0.1, 0.4, and 0.6 log IU/mL at weeks 20, 44 and 68, respectively). On-treatment serum HBsAg decrease had a high accuracy to predict SVR (AUROC = 0.88). Our results suggest that sequential therapy might be an interesting strategy for HBeAg-negative patients. Serum HBsAg kinetics seem to be an accurate tool to predict SVR. Large clinical trials are needed to explore this strategy with more potent analogues.

Viral hepatitis in solid organ transplantation other than liver

Transplantation is the best treatment for end-stage organ failure. Hepatitis virus infections, mainly hepatitis B virus (HBV) and hepatitis C virus (HCV) infections still constitute a major problem because they are common in allograft recipients and are a significant cause of morbidity and mortality after transplantation. Recently, hepatitis E virus infection has been added as an emergent cause of chronic hepatitis in organ transplantation. The prevalence of HBV and HCV infections has markedly decreased in patients who are candidates for transplantation since the introduction of screening, hygiene and prevention measures, including systematic screening of blood and organ donations, use of erythropoietin, compliance with universal hygiene rules, segregation of HBV-infected patients from non-infected patients and systematic vaccination against HBV. A liver biopsy is preferable to non-invasive biochemical and/or morphological tests of fibrosis to evaluate liver fibrosis before and even after transplantation. Treatment with entecavir or tenofovir is indicated in HBV-infected dialyzed patients who have moderate or severe disease (≥A2 or F2 on the Metavir scale) in preparation for renal transplantation. Due to the risks of severe reactivation, fibrosing cholestatic hepatitis or histological deterioration after transplantation, systematic use of nucleoside or nucleotide analogues shortly before or at the time of transplantation is recommended (tenofovir or entecavir are preferable to lamivudine) in all patients, whatever the baseline histological evaluation. In HCV-infected dialyzed patients who are not candidates for renal transplantation, the indication for antiviral therapy is limited to significant fibrosis (fibrosis ≥2 on the Metavir scale). Treatment must be proposed to all candidates for renal transplantation, whatever their baseline histopathology, and interferon-α should be used as monotherapy. After transplantation, interferon-α is contraindicated but may be used in patients for whom the benefits of antiviral treatment clearly outweigh the risks, especially that of allograft rejection. All cirrhotic patients, notably after solid organ transplantation, should be screened for hepatocellular carcinoma. Sustained suppression of necro-inflammation may result in regression of cirrhosis, which in turn may lead to decreased disease-related morbidity and improved survival. Finally, due to the high mortality after renal transplantation, active (namely without sustained viral suppression) cirrhosis should be considered a contraindication to kidney transplantation, but an indication to combined liver-kidney transplantation; on the contrary, inactive (namely with sustained viral suppression) compensated cirrhosis may permit renal transplantation alone. Organ transplantations other than kidney (cardiac or pulmonary transplantations) involve the same diagnosis and therapeutic issues.

Management of chronic hepatitis B

Chronic hepatitis B continues to be a major global health burden. It accounts for a substantial impact on health care resources and finances in many parts of the world including Europe. Natural history and disease spectrum are varied, depending on when and how the infection is acquired. The chronic infective state increases patients' risk of progression to liver cirrhosis or hepatocellular carcinoma. Several treatment options are currently available, but their use depends on the stage of the patient's infection, which is influenced by both host and viral factors. The ultimate goals in hepatitis B treatment are to prevent disease progression, hepatic decompensation, hepatocellular carcinoma, and death. Patients with decompensated liver cirrhosis should be referred to specialized transplant centers in a timely manner.

Recent advances in the management of chronic hepatitis B

There are seven approved treatments for adults with chronic hepatitis B virus infection in the United States and European countries: interferon-α, pegylated interferon-α, lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate. At present, two new analogues, entecavir and tenofovir are recommended as the first line therapy by the guidelines of European Association for the Study of the Liver and American Association Study for the Liver Diseases. On the other hand, regarding interferon therapy, use of pegylated interferon-α is recommended as the first line therapy instead of standard interferon-α by both guidelines. Therefore, the main scientific interests and unmet medical needs for treatment of chronic hepatitis B have been narrowed down to long-term efficacy and safety of the two said analogues-entecavir and tenofovir-and combination therapy of pegylated interferon-α with the two analogues. To put it concretely, further studies are needed to assess (1) the long-term efficacy and safety and resistance to entecavir and tenofovir; (2) the efficacy of different durations (24 weeks to 2 years) and lower doses of pegylated interferon-α; (3) the role of combination therapy with two analogues to reduce resistance; and (4) the efficacy and safety of the two analogues with decompensated cirrhosis. Herein, we review the recent available data and results.

[Interferon-based versus direct antiviral therapy in patients with chronic hepatitis B]

Treatment of chronic hepatitis B is still challenging. Lots of parameters are needed to be considered before and during the therapy. There are several possible endpoints and their durability is very much variable. Patients with HBeAg-positive and HBeAg-negative hepatitis B need treatment. Two different strategies are available. Interferon-based therapy is a limited treatment, which might result in a sustained immune response in about one third of the patients, leading to an induced remission, sometimes years after the end of the treatment. According to the other strategy a continuous, indefinite oral nucleoside/nucleotide analogue (NA) treatment is administered to maintain a remission. However, relapse is rather frequent after the cessation of this therapy. During the long-term NA treatment drug resistance can lead to the loss of antiviral effect. Three first-line drugs are recommended, pegylated interferon alfa-2a, entecavir and tenofovir. If there is no contraindication to interferon, it is worth trying to achieve immune control and an induced remission. In patients, who do not respond to interferon, a sequential NA therapy is indicated.

Hepatitis B surface antigen monitoring and management of chronic hepatitis B

Serum hepatitis B surface antigen (HBsAg) levels reflect intrahepatic hepatitis B virus (HBV) covalently closed circular DNA and may be a valuable addition to HBV DNA in the management of patients with chronic hepatitis B (CHB). Among HBeAg-negative CHB patients with low HBV DNA levels, HBsAg quantification may help distinguish those with active CHB from true inactive carriers with a very favourable prognosis, thus limiting the need for long-term intensive monitoring of ALT and HBV DNA levels. In patients treated with peginterferon (PEG-IFN), achievement of a decline in HBsAg during therapy appears to be an important marker for treatment outcome, and several groups have proposed stopping rules based on HBsAg thresholds. A recently described stopping rule incorporating a combination of HBsAg and HBV DNA levels can accurately identify HBeAg-negative patients, especially those with HBV genotype D, not responding to PEG-IFN. Current applications of HBsAg levels in the monitoring of patients treated with nucleo(s)tide analogues are still being evaluated. First data from these studies show that HBsAg decline, and thus subsequent clearance, is confined to those with an active immune response to HBV, such as HBeAg-positive patients with elevated ALT, or those who achieve HBeAg clearance.

Development and validation of a hepatitis B virus DNA sequencing assay for assessment of antiviral resistance, viral genotype and surface antigen mutation status

The objective of this study was to develop a DNA sequencing assay that examines sensitively and reliably all conserved domains of the reverse transcriptase-encoding region of the HBV genome for antiviral resistance-associated mutations while simultaneously producing ample information for precise genotyping and determination of HBsAg mutation. This assay was used to examine 1000 de-identified HBV DNA positive samples with known viral loads from a broad-based, unselected patient population from across the United States. Of these, 946 were assayed successfully. Antiviral resistance-associated mutations were identified in 104 samples. The escape mutation sG145R in the surface antigen was identified in 0.8% of patient samples. Infections with genotypes A, B, C, D, E, F, G and H were observed in 36.6%, 19.6%, 21.7%, 13.5%, 3.6%, 0.7%, 2.2%, and 0.5% of patient samples respectively. Fifteen samples (1.6%) appeared to harbor infections with multiple genotypes as shown by the presence of double peaks throughout sequence electropherograms. The limit of detection of this assay was approximately 150IU/mL.

Recent advances in the treatment of chronic hepatitis B

INTRODUCTION

At present, two strategies exist for the treatment of chronic hepatitis B (CHB): i) standard or pegylated interferon alpha (IFN) with mainly immune modulatory effects; and ii) nucleos(t)ide analogues (NA) with direct antiviral effects. The optimal treatment for an individual patient remains controversial.

AREAS COVERED

The treatment efficacy and prediction of response to antiviral agents for chronic hepatitis B are reviewed and discussed.

EXPERT OPINION

The rates of hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) loss or seroconversion are continuously increasing in CHB patients after stopping a finite course of IFN, whereas long-term NA therapy is usually required to improve the adverse outcomes of CHB. Lower baseline HBV DNA level is a strong predictor for both sustained viral suppression and HBeAg seroconversion in patients receiving IFN-based as well as NAs therapy. In addition, HBeAg-positive patients with genotype A or B infection have better responses to IFN-based therapy than those with genotypes C or D infection. Furthermore, on-treatment predictors such as declines of serum HBV DNA, HBsAg and HBeAg levels may be helpful in making decisions of subsequent therapy. Regarding the association of host genetic factors with responses to antiviral therapy, current evidence is limited.

Tenofovir disoproxil fumarate for the treatment of chronic hepatitis B monoinfection

INTRODUCTION

Resistance in nucleoside/nucleotide analog (NA) therapy has always been a challenge in the management of chronic hepatitis B (CHB).

CLINICAL STUDIES

Initially developed for the treatment of HIV infection, early in vitro and clinical observational studies had shown tenofovir disoproxil fumarate (TDF) to be also active against CHB. Recent data from various multicenter phase 3 and 4 clinical trials have confirmed TDF being able to achieve a high viral suppression in both NA-naive and -experienced CHB patients. There are also emerging data on the efficacy of TDF in decompensated CHB. Although there are in vitro studies identifying certain mutation loci associated with a reduced susceptibility to TDF, there have so far been no reports of virologic resistance to TDF in clinical studies. TDF has a favorable safety profile, although more long-term data would be needed.

CONCLUSIONS

TDF has the makings of an "ideal" first-line drug for the treatment of CHB.

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.

Drug safety evaluation of adefovir in HBV infection

INTRODUCTION

Several nucleos(t)ide analogs (NUC) are available for the management of patients with chronic hepatitis B (CHB). In most patients, NUC need to be administered on a long-term basis, thus increasing the risk of adverse effects. Adefovir dipivoxil (ADV), the first nucloeotide analog developed to treat CHB, may indeed cause nephrotoxicity.

AREAS COVERED

The pharmacokinetic mechanism of action, potential mechanism of renal damage and long-term safety profile of ADV in CHB patients have been reported. The current monitoring modalities, together with dosage adjustments, treatment of patients with ADV-related kidney impairment and the therapeutic algorithm in place at the authors' Liver Center are also summarized. Although, in short-term clinical trials, a daily dose of 10 mg of ADV was safe owing to a low rate of negligible nephrotoxic effects, the same dose may be associated with a usually reversible, proximal renal tubular toxicity as reflected by hypophosphatemia and elevated creatinine levels. Occasionally, Fanconi syndrome occurred in ADV-treated patients.

EXPERT OPINION

Renal function at baseline and during treatment should be carefully assessed in all patients receiving ADV to adjust the dose according to creatinine clearance, aimed to prevent or minimize nephrotoxicity.

Long-term effect of interferon plus ribavirin on hepatitis B surface antigen seroclearance in patients dually infected with hepatitis B and C viruses

Background

Interferon-α/ribavirin combination therapy might promote hepatitis B surface antigen (HBsAg) seroclearance in patients dually infected with hepatitis B and C viruses (HBV/HCV), but the long-term effect remains unclear. We aimed to investigate the rate of and the factors associated with HBsAg seroclearance during long-term follow-up after interferon-α/ribavirin combination therapy in HBV/HCV dually-infected patients.

Methodology/Principal Findings

Eighty-one patients who received interferon-α/ribavirin combination therapy for 24 weeks with a follow-up period of >24 weeks were enrolled. HBV serological markers and HBV DNA were determined every 6 months. Early and late HBsAg seroclearance were defined as HBsAg loss in less or more than 6 months after end-of-treatment, respectively. Fifteen (18.5%) patients had HBsAg seroclearance during a mean follow-up period of 3.4 (0.5–5.1) years. The 5-year cumulative incidence was 25.6%. Baseline cirrhosis and HBV DNA negativity 1 year after end-of-treatment were independently predictive of HBsAg seroclearance with an odds ratio (OR), 95% confidence intervals (CI) of 16.6, 1.8–153 and 9.2, 1.4–62.1, respectively, by Cox regression hazard analysis. Four patients developed early and 11 developed late HBsAg seroclearance, respectively. Cox regression hazard analysis showed no factor was associated with early HBsAg seroclearance, whilst HBV DNA negativity 1 year after end-of-treatment was the only significant factor predicting late HBsAg loss (OR, 43.0; CI, 2.5–745). Five patients had HBsAg seroconversion with a 5-year cumulative incidence of 8.3%. HBV DNA negativity at baseline and one year after EOT had a trend for HBsAg seroconversion. HCV response did not correlate to HBsAg loss.

Conclusions

We demonstrated that interferon-α/ribavirin had long-term effect on HBsAg seroclearance in dually HBV/HCV-infected patients. Baseline cirrhosis and seroclearance of HBV DNA 1 year after end-of-treatment were significant factors associated with HBsAg seroclearance.

Peginterferon alpha-based therapy for chronic hepatitis B focusing on HBsAg clearance or seroconversion: a meta-analysis of controlled clinical trials

BACKGROUND

Interferon alpha (IFNα) therapy has been widely used in the treatment of chronic hepatitis B (CHB) for decades. Nucleos(t)ide analogues are also increasingly used to treat CHB recently. More and more studies are being carried out concerning the clearance or seroconversion of HBsAg, which is recognized as an ideal goal of CHB therapy. This study conducted a meta-analysis to estimate the effect of pegylated interferon alpha (peginterferon α, PEG-IFNα)-based therapy on HBsAg clearance or seroconversion in CHB.

METHODS

All available controlled clinical trials, published from 2004 to 2010, with the following antiviral therapies for CHB patients: PEG-IFNα combined with lamivudine (LAM), PEG-IFNα only, conventional IFNα and LAM, with a course ≥24 weeks, were meta-analysed for HBsAg clearance and seroconversion.

RESULTS

Fourteen trials (involving a total of 2,682 patients) were identified, including seven high-quality and seven low-quality studies. The analysis results of the different antiviral therapies on HBsAg clearance or seroconversion were as follows: 1. No significant difference in HBsAg clearance or seroconversion was observed between the combination therapy group and PEG-IFNα monotherapy group [odds ratio (OR) = 1.16, 95% confidence intervals (CI) (0.73-1.85), P = 0.54 and OR = 1.07, 95% CI (0.58-1.97), P = 0.82, respectively]; 2. HBsAg clearance and seroconversion rates in patients with combination therapy were markedly higher than in those with LAM monotherapy [OR = 9.41, 95% CI (1.18-74.94), P = 0.03, and OR = 12.37, 95% CI (1.60-95.44), P = 0.02, respectively]; 3. There was significant difference in HBsAg clearance between the PEG-IFNα group and IFNα monotherapy group [OR = 4.95, 95% CI (1.23-20.00), P = 0.02], but not in seroconversion [OR = 2.44, 95% CI (0.35-17.08), P = 0.37]; 4. PEG-IFNα was superior to LAM in HBsAg seroconversion [OR = 14.59, 95% CI (1.91-111.49), P = 0.01].

CONCLUSIONS

PEG-IFNα facilitated HBsAg clearance or seroconversion in CHB patients. PEG-IFNα-based therapy was more effective than LAM monotherapy in achieving HBsAg clearance or seroconversion for both HBeAg-positive and HBeAg-negative CHB patients. There was no significant difference in HBsAg clearance or seroconversion between PEG-IFNα/LAM combination therapy and PEG-IFNα monotherapy. PEG-IFNα was obviously superior to conventional IFNα in HBsAg clearance, but not in HBsAg seroconversion. Although PEG-IFNα produced significantly higher rates of HBsAg clearance and seroconversion, the absolute change in the proportion of HBsAg clearance and seroconversion was low (about 3-6%). Therefore, additional interventions are needed to improve the rate of positive outcomes.

Peginterferon alpha-based therapy for chronic hepatitis B focusing on HBsAg clearance or seroconversion: a meta-analysis of controlled clinical trials

Background

Interferon alpha (IFNα) therapy has been widely used in the treatment of chronic hepatitis B (CHB) for decades. Nucleos(t)ide analogues are also increasingly used to treat CHB recently. More and more studies are being carried out concerning the clearance or seroconversion of HBsAg, which is recognized as an ideal goal of CHB therapy. This study conducted a meta-analysis to estimate the effect of pegylated interferon alpha (peginterferon α, PEG-IFNα)-based therapy on HBsAg clearance or seroconversion in CHB.

Methods

All available controlled clinical trials, published from 2004 to 2010, with the following antiviral therapies for CHB patients: PEG-IFNα combined with lamivudine (LAM), PEG-IFNα only, conventional IFNα and LAM, with a course ≥24 weeks, were meta-analysed for HBsAg clearance and seroconversion.

Results

Fourteen trials (involving a total of 2,682 patients) were identified, including seven high-quality and seven low-quality studies. The analysis results of the different antiviral therapies on HBsAg clearance or seroconversion were as follows: 1. No significant difference in HBsAg clearance or seroconversion was observed between the combination therapy group and PEG-IFNα monotherapy group [odds ratio (OR) = 1.16, 95% confidence intervals (CI) (0.73-1.85), P = 0.54 and OR = 1.07, 95% CI (0.58-1.97), P = 0.82, respectively]; 2. HBsAg clearance and seroconversion rates in patients with combination therapy were markedly higher than in those with LAM monotherapy [OR = 9.41, 95% CI (1.18-74.94), P = 0.03, and OR = 12.37, 95% CI (1.60-95.44), P = 0.02, respectively]; 3. There was significant difference in HBsAg clearance between the PEG-IFNα group and IFNα monotherapy group [OR = 4.95, 95% CI (1.23-20.00), P = 0.02], but not in seroconversion [OR = 2.44, 95% CI (0.35-17.08), P = 0.37]; 4. PEG-IFNα was superior to LAM in HBsAg seroconversion [OR = 14.59, 95% CI (1.91-111.49), P = 0.01].

Conclusions

PEG-IFNα facilitated HBsAg clearance or seroconversion in CHB patients. PEG-IFNα-based therapy was more effective than LAM monotherapy in achieving HBsAg clearance or seroconversion for both HBeAg-positive and HBeAg-negative CHB patients. There was no significant difference in HBsAg clearance or seroconversion between PEG-IFNα/LAM combination therapy and PEG-IFNα monotherapy. PEG-IFNα was obviously superior to conventional IFNα in HBsAg clearance, but not in HBsAg seroconversion. Although PEG-IFNα produced significantly higher rates of HBsAg clearance and seroconversion, the absolute change in the proportion of HBsAg clearance and seroconversion was low (about 3-6%). Therefore, additional interventions are needed to improve the rate of positive outcomes.

Virological breakthrough and resistance in patients with chronic hepatitis B receiving nucleos(t)ide analogues in clinical practice

Virological breakthrough (VBT) is the first manifestation of antiviral drug resistance during nucleos(t)ide analogue (NUC) treatment of chronic hepatitis B (CHB), but not all VBTs are due to drug resistance. This study sought to determine the incidence of VBT and genotypic resistance (GR) in patients with CHB who were receiving NUCs in clinical practice. Records of patients with CHB who were receiving NUCs were reviewed. All patients with VBT were tested for drug resistance mutations. Of 148 patients included, 73% were men and mean age was 44.9 years. During a mean follow-up of 37.5 ± 20.1 months, 39 (26%) patients had at least 1 VBT. Of these 39 patients, 15 (38%) were not confirmed to have VBT on retesting, and 10 of these 15 had no evidence of GR. The cumulative probability of VBT, confirmed VBT, and GR at 5 years was 46.1%, 29.7%, and 33.9%, respectively. In multivariate analysis, failure to achieve undetectable hepatitis B virus (HBV) DNA was the only factor significantly associated with VBT. Among the 10 patients who had VBT but no confirmed VBT or GR and who were maintained on the same medications, serum HBV DNA decreased in all 10, and nine had undetectable HBV DNA at a mean of 6.8 months after the VBT. Four patients had persistently undetectable HBV DNA, six had transient increase in HBV DNA during follow-up, and none had GR.

CONCLUSION

VBT was common in patients with CHB receiving NUCs in clinical practice, but nearly 40% of the VBTs were not related to antiviral drug resistance. Counseling of patients with CHB on medication adherence and confirmation of VBT and/or GR can avoid unnecessary changes in antiviral medications.

The cost-effectiveness of screening for chronic hepatitis B infection in the United States

BACKGROUND

Hepatitis B virus (HBV) continues to cause significant morbidity and mortality in the United States. Current guidelines suggest screening populations with a prevalence of ≥2%. Our objective was to determine whether this screening threshold is cost-effective and whether screening lower-prevalence populations might also be cost-effective.

METHODS

We developed a Markov state transition model to examine screening of asymptomatic outpatients in the United States. The base case was a 35-year-old man living in a region with an HBV infection prevalence of 2%. Interventions (versus no screening) included screening for Hepatitis B surface antigen followed by treatment of appropriate patients with (1) pegylated interferon-α2a for 48 weeks, (2) a low-cost nucleoside or nucleotide agent with a high rate of developing viral resistance for 48 weeks, (3) prolonged treatment with low-cost, high-resistance nucleoside or nucleotide, or (4) prolonged treatment with a high-cost nucleoside or nucleotide with a low rate of developing viral resistance. Effectiveness was measured in quality-adjusted life years (QALYs) and costs in 2008 US dollars.

RESULTS

Screening followed by treatment with a low-cost, high-resistance nucleoside or nucleotide was cost-effective ($29,230 per QALY). Sensitivity analyses revealed that screening costs <$50,000 per QALY in extremely low-risk populations unless the prevalence of chronic HBV infection is <.3%.

CONCLUSIONS

The 2% threshold for prevalence of chronic HBV infection in current Centers for Disease Control and Prevention/US Public Health Service screening guidelines is cost-effective. Furthermore, screening of adults in the United States in lower-prevalence populations (eg, as low as .3%) also is likely to be cost-effective, suggesting that current health policy should be reconsidered.

Association of intrahepatic cccDNA reduction with the improvement of liver histology in chronic hepatitis B patients receiving oral antiviral agents

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is difficult to eradicate using current antiviral therapy. This study compares cccDNA reduction with relation to liver histology in nucleoside/nucleotide-naïve chronic hepatitis B patients receiving oral antiviral monotherapy (n=35), including entecavir (ETV, n=13), adefovir dipivoxil (ADV, n=22) or placebo (n=14). Serum HBV DNA, intrahepatic total HBV DNA and cccDNA are quantified. Histological hepatic examination is performed at baseline and at 48 weeks of treatment. Treatment with ETV or ADV shows significant median reduction in serum HBV DNA (-6.21 and -4.27 log(10) copies/mL) and intrahepatic total HBV DNA (-1.69 and -1.23 log(10) copies/cell). Intrahepatic cccDNA levels are reduced slightly in the ETV and the ADV groups, but do not differ statistically from the placebo group (-0.17 vs. -0.01 vs. 0.02 copies/cell). Only the level of intrahepatic cccDNA correlates with Knodell necroinflammation activity (r=0.527, P<0.001) and Ishak fibrosis severity (r=0.348, P=0.015) before treatment. Multivariate logistic regression analysis indicates that treatment-induced cccDNA reduction is associated with improved necroinflammation (P=0.041) and fibrosis (P=0.026). In conclusion, baseline intrahepatic cccDNA loads correlate with histologic activity. Although one-year ETV or ADV treatment is insufficient for cccDNA eradication, oral antiviral therapies may improve liver histology, probably by suppressing intrahepatic cccDNA.

Update of chronic hepatitis B

PURPOSE OF REVIEW

We review here new developments in chronic hepatitis B (CHB) treatment, based on review of published articles between December 2009 and November 2010.

RECENT FINDINGS

It is estimated that two-thirds of US CHB patients have not been identified, evaluated and appropriately treated, largely due to lack of knowledge and awareness of CHB among medical professionals and at-risk populations. Seven medications have been approved to treat CHB in adults, but only four medications have been approved to treat CHB in children.Hepatitis B e antigen (HBeAg) seroconversion is still an important treatment endpoint in HBeAg-positive patients. Durability of nucleoside analogue treatment-related HBeAg seroconversion is still questionable. Hepatitis B surface antigen (HBsAg) seroclearance has been achieved in some patients with antiviral therapy. HBsAg quantitation and kinetics is now being studied to determine its role in the natural history of CHB and whether these measures may predict future response to current antiviral therapy.

SUMMARY

Great advances have been made in understanding the HBeAg seroconversion durability. The clinical significance of serum HBsAg kinetics has been recognized in naive CHB patients and patients with antiviral therapy. More education programs are needed to improve the public awareness of the importance of CHB to the health of whole population.

Hepatitis B therapy

The goal of hepatitis B treatment is to prevent cirrhosis, liver decompensation and hepatocellular carcinoma. In clinical practice, treatment response is determined by suppression of serum HBV DNA levels, hepatitis B e antigen seroconversion to hepatitis B e antibody, hepatitis B surface antigen loss, normalization of alanine aminotransferase levels and improvement in liver histology. Patients with life-threatening liver disease, and those with high levels of HBV replication and active or advanced liver disease, should be treated. Other patients should be monitored so that treatment can be initiated when indicated. Currently, seven medications are approved for the treatment of hepatitis B: two formulations of interferon and five nucleos(t)ide analogues. Interferon is administered for a finite duration while nucleos(t)ide analogues are usually administered for many years. Antiviral drug resistance is a major limiting factor to the success of nucleos(t)ide analogue treatment; therefore, treatment should be initiated with drugs that have a high genetic barrier to resistance (that is, a low potential for drug resistance). In addition, treatment response should be closely monitored to detect virologic breakthroughs, and the importance of medication adherence should be emphasized. Management of patients with treatment failure should be tailored according to the type of treatment failure (lack of initial response versus virologic breakthrough), the treatment that the patient is receiving, history of prior treatment, and the pretreatment characteristics of both the patient and the disease.

Detection of lamivudine- or adefovir-resistant hepatitis B virus mutations by a liquid array

A novel polymerase chain reaction (PCR)-Luminex assay was developed for rapid, accurate, and high-throughput detection of the most important hepatitis B virus (HBV) variants, including those with reverse transcriptase (RT) domain L180M, M204I/V, A181T/V/S, I233V and N236T mutations associated with resistance to lamivudine (LAM) or adefovir (ADV). Using mixtures of mutant and wild-type HBV, this method was sufficiently sensitive for detecting 10(3)HBV ml(-1) and could detect minor mutants when they comprised 5% of the total viral population. Comparison of the PCR-Luminex assay with INNO-LiPA for detecting clinical LAM- or ADV-resistant chronic hepatitis B virus infection in 64 patients confirmed the following: the 2 methods were 97.9% (48 of 49) and 93.3% (14 of 15) concordant for detecting LAM- or ADV-resistance mutations, respectively. The agreement with direct sequencing was 70.3% (45 of 64). The PCR-Luminex assay or multi-analyte suspension array can detect simultaneously and efficiently minor populations HBV mutants early during infection in many clinical samples. It is a simple, cost-effective method for resistance surveillance or selecting appropriate antiviral agents and initiating timely rescue treatment before the development drug-resistance related virus or biochemical breakthrough.

Profile of HBV antiviral resistance mutations with distinct evolutionary pathways against nucleoside/nucleotide analogue treatment among Chinese chronic hepatitis B patients

BACKGROUND

Antiviral drug-resistant HBV mutants under a variety of treatment protocols are complex and only partly understood. Here, a population-based cross-sectional study was performed to analyse the profile of resistance mutations in distinct evolutionary pathways refractory to different nucleoside/nucleotide analogues (NAs).

METHODS

Serum samples of 199 chronic hepatitis B patients undergoing NA treatment from five hospitals in four northern cities of China were obtained between January 2007 and July 2009. The genotypic resistance of HBV in these samples was characterized. The full-length HBV reverse transcriptase region was amplified, sequenced and analysed with particular focus on the following NA-resistant changes: rtL80, rtI169, rtV173, rtL180, rtA181, rtT184, rtA194, rtS202, rtM204, rtN236 and rtM250.

RESULTS

Among 199 HBV isolates, 30 (15.08%) and 169 (84.92%) were genotypes B and C, respectively, and 65 (32.66%) harboured NA-resistant mutations. The prevalence of mutations at rtM204 was 34.33% in 134 patients who had received or who had been exposed to lamivudine-based therapy. Five cases of rtN236 mutations were detected exclusively among 75 patients receiving adefovir-dipivoxil-based therapies. A total of 19 cases of multidrug resistance rtA181 mutations were observed in those with lamivudine-, adefovir-dipivoxil- or telbivudine-based treatment (186 cases), but not in those undergoing entecavir treatment (13 cases). Mutations were not found at rtI169, rtT184, rtA194 or rtS202. rtM204 mutations (27 rtM204I, 15 rtM204V and 5 rtM204I/V cases) were detected at the highest frequency among 65 mutants (72.30% [47/65]) and found to display 16 combination mutation patterns, in which rtM204I and rtM204V were significantly associated with rtL80I/V and rtL180M, respectively (P<0.01).

CONCLUSIONS

One-third of the studied population harboured NA-resistant HBV with complicated mutation patterns. Monitoring HBV genotypic resistance mutation markers and patterns is therefore shown to be beneficial for optimizing antiviral therapies and for avoiding clinical deterioration.