Nucleos(t)ide analogues for hepatitis B virus: strategies for long-term success

Arsenic trioxide impacts hepatitis B virus core nuclear localization and efficiently interferes with HBV infection

The key to a curative treatment of hepatitis B virus (HBV) infection is the eradication of the intranuclear episomal covalently closed circular DNA (cccDNA), the stable persistence reservoir of HBV. Currently, established therapies can only limit HBV replication but fail to tackle the cccDNA. Thus, novel therapeutic approaches toward curative treatment are urgently needed. Recent publications indicated a strong association between the HBV core protein SUMOylation and the association with promyelocytic leukemia nuclear bodies (PML-NBs) on relaxed circular DNA to cccDNA conversion. We propose that interference with the cellular SUMOylation system and PML-NB integrity using arsenic trioxide provides a useful tool in the treatment of HBV infection. Our study showed a significant reduction in HBV-infected cells, core protein levels, HBV mRNA, and total DNA. Additionally, a reduction, albeit to a limited extent, of HBV cccDNA could be observed. Furthermore, this interference was also applied for the treatment of an established HBV infection, characterized by a stably present nuclear pool of cccDNA. Arsenic trioxide (ATO) treatment not only changed the amount of expressed HBV core protein but also induced a distinct relocalization to an extranuclear phenotype during infection. Moreover, ATO treatment resulted in the redistribution of transfected HBV core protein away from PML-NBs, a phenotype similar to that previously observed with SUMOylation-deficient HBV core. Taken together, these findings revealed the inhibition of HBV replication by ATO treatment during several steps of the viral replication cycle, including viral entry into the nucleus as well as cccDNA formation and maintenance. We propose ATO as a novel prospective treatment option for further pre-clinical and clinical studies against HBV infection.

IMPORTANCE

The main challenge for the achievement of a functional cure for hepatitis B virus (HBV) is the covalently closed circular DNA (cccDNA), the highly stable persistence reservoir of HBV, which is maintained by further rounds of infection with newly generated progeny viruses or by intracellular recycling of mature nucleocapsids. Eradication of the cccDNA is considered to be the holy grail for HBV curative treatment; however, current therapeutic approaches fail to directly tackle this HBV persistence reservoir. The molecular effect of arsenic trioxide (ATO) on HBV infection, protein expression, and cccDNA formation and maintenance, however, has not been characterized and understood until now. In this study, we reveal ATO treatment as a novel and innovative therapeutic approach against HBV infections, repressing viral gene expression and replication as well as the stable cccDNA pool at low micromolar concentrations by affecting the cellular function of promyelocytic leukemia nuclear bodies.

Efficacy and safety of chimeric antigen receptor T cell therapy in relapsed/refractory diffuse large B-cell lymphoma with different HBV status: a retrospective study from a single center

Background

Chimeric antigen receptor T cell (CAR-T) therapy is an effective salvage treatment in relapsed or refractory(r/r) diffuse large B-cell lymphoma (DLBCL), but the impact of hepatitis B virus (HBV) infection has not been studied.

Methods and results

Here, 51 patients with r/r DLBCL receiving CAR-T therapy were enrolled and analyzed at the First Affiliated Hospital of Soochow University. The overall response rate and the complete remission rate (CR) of CAR-T therapy were 74.5% and 39.2%, respectively. With a median follow-up of 21.1 months after CAR-T, the probabilities of overall survival (OS) and progression-free survival (PFS) at 36 months were 43.4% and 28.7%, respectively. These patients were divided into three cohorts including chronic HBV infection group (n=6), resolved HBV infection group (n=25) and non-HBV infection group (n=20). Bone marrow involvement was significantly higher in the HBV infection group(P<0.001), other basic characteristics before CAR-T therapy were comparable. Subgroup analysis showed that HBV infection status did not affect the efficacy of CAR-T therapy in CR rate, OS or PFS, and there was no significant difference in CAR-T related toxicities between three cohorts. Only one cirrhosis patient with chronic HBV infection experienced HBV reactivation.

Conclusions

CAR-T therapy was effective and can be used safely in r/r DLBCL with HBV infection under proper monitoring and antiviral prophylaxis.

Case Report: Post-CAR-T Infusion HBV Reactivation in Two Lymphoma Patients Despite Entecavir Preventive Therapy

Hepatitis B virus (HBV) reactivation is a common complication in chronic or resolved HBV infection patients undergoing immunosuppressive chemotherapy. Furthermore, few articles have been published regarding the risk of HBV reactivation in lymphoma patients receiving chimeric antigen receptor (CAR) T-cell therapy and anti-HBV prophylaxis. Few guidelines or clear optimal strategies are available for managing these patients. Here, we present two cases of patients who underwent CAR-T-cell cocktail therapy with anti-CD19 and anti-CD22 CAR (CAR19/22) T cell for lymphoma. Patients had previous history of HBV infection, and blood tests on initial admission indicated positive results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and antibody to hepatitis B e antigen (anti-HBe), while serum HBV DNA level was undetectable. Therefore, two patients received entecavir as antiviral prophylactic therapy during their entire treatment. They were diagnosed with HBV reactivation based on positive serum HBV DNA test results, 2 weeks after CAR-T-cell infusion. Liver function assay indicated elevated levels of alanine transaminase (ALT) and aspartate transaminase (AST), combined with increased levels of total bilirubin (TBIL) and direct bilirubin (DBIL). Subsequently, they received anti-HBV treatment with entecavir and tenofovir. As a result, their serum HBV DNA copies and AST/ALT levels returned to normal after 1 week. These cases show that there is a risk of HBV reactivation in lymphoma patients with CAR-T-cell therapy despite entecavir preventive therapy, and combination treatment of entecavir and tenofovir may be an effective treatment option for such patients with HBV reactivation.

Reduced Incidence of Hepatocellular Carcinoma in Cirrhotic and Noncirrhotic Patients With Chronic Hepatitis B Treated With Tenofovir-A Propensity Score-Matched Study

Background

The effect of newer oral anti-hepatitis B virus (HBV) medication, tenofovir disoproxil (TDF), on liver-related outcomes among Asians is limited. We examined the effect of TDF on the incidence of hepatocellular carcinoma (HCC) in an Asian population with chronic hepatitis B (CHB).

Methods

This was a retrospective cohort study of 6914 adults with chronic HBV monoinfection and no history of transplantation who were recruited from 6 US referral, community medical centers and a community based Taiwan cohort for a total of 774 patients who received TDF and 6140 who were not treated. Propensity score matching (PSM) for age, sex, HBV e antigen status, HBV DNA level, alanine aminotransferase (ALT) level, baseline cirrhosis status, and follow-up time was performed to balance the groups, resulting in 591 treated individuals and 591 untreated individuals. Kaplan-Meier analysis was used to estimate the cumulative risk of HCC. Cox proportional hazards models were run to estimate the HCC risk between groups.

Results

The 8-year cumulative HCC incidence was significantly higher in the PSM untreated group (20.13% vs 4.69%; P < .0001). Cirrhosis was a significant predictor for HCC (adjusted hazard ratio [aHR], 5.36; 95% confidence interval [CI], 2.73-10.51; P < .001). On multivariate analysis adjusted for age, sex, HBV DNA level, ALT level, and study site, TDF was associated with a 77% reduction in the risk of HCC (aHR, 0.23; 95% CI, .56-.92) in patients with cirrhosis and a 73% reduction (aHR, 0.27; 95% CI, .07-.98) in patients without cirrhosis.

Conclusions

Among cirrhotic and noncirrhotic Asian patients with CHB, TDF therapy was significantly associated with a reduction in the 8-year HCC cumulative incidence rate.

Long-term outcomes with oral therapy in liver transplant recipients with hepatitis B

BACKGROUND

The long-term impact of oral hepatitis B antiviral therapy in liver transplant (LT) recipients is currently underexplored. The objective of this study was to evaluate how oral antiviral agents impact long-term renal function in this population.

METHODS

We studied 79 patients who received a LT for hepatitis B and were placed on all-oral antiviral therapy after withdrawing from hepatitis B immune globulin therapy at the University of California, Los Angeles. Laboratory data were obtained through a retrospective chart review. Univariate analysis and two-sided t tests were performed.

RESULTS

The mean (±SD [standard deviation]) age at the time of LT was 65.4 (± 8.2) years. The overall mean (±SD) follow-up from LT was 6.5 (±3.3) years. 22.8% (18/79) of recipients on all-oral therapy had worsening of their chronic kidney disease stage, and 17.7% (14/79) had an increase in creatinine of at least 0.3 mg/dL. There were no significant changes in creatinine and GFR in patients while on tenofovir alafenamide. Patient survival was decreased for recipients who developed detectable HBsAg.

CONCLUSION

Tenofovir alafenamide appears to have less of an impact on renal function in LT recipients than other antiviral agents. HBV recurrence after transplant is associated with decreased patient survival and remains an important issue to address for LT recipients on oral antiviral therapy.

Taiwan consensus statement on the management of chronic hepatitis B

The experts of Taiwan Association for the Study of Liver (TASL) have actively participated and led the guidelines on hepatitis B virus (HBV) management by Asian Pacific Association for the Study of Liver (APASL) which is the first international association for the study of liver to publish the statement on HBV management before. However, there are more and more new data on the natural history and treatment of HBV infection in the past decade. These include new application of an old biomarker (quantitative HBsAg), clinical significance of HBV genotype and naturally occurring mutations, the role of non-invasive examination in evaluating severity of hepatic fibrosis, clinical significance of outcome calculators, new drug or new combination strategies towards more effective therapy and organ transplantation including liver and non-liver transplantation. It is time to publish the guidelines on HBV management of Taiwan. Hence, TASL have conducted an expert meeting to review, to discuss and to debate the relevant literatures, followed by draft the manuscript of HBV management guidelines and recommendations. The guidelines include general management, indications for fibrosis assessment, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patient receiving immune suppression or chemotherapy and patients in the setting of liver transplantation and hepatocellular carcinoma, are also included.

Clinical and virological outcomes of entecavir therapy in patients with chronic hepatitis B: A real life experience

BACKGROUND

Entecavir (ETV) is a nucleoside analogue (NA) that is effective for treatment of chronic hepatitis B (CHB) due to its low resistance rates and potent antiviral effects. We aimed to evaluate the clinical, biochemical and virological response to ETV in patients without a prior use of nucleos(t)ide (NA-naïve) vs. those who failed prior NA use (NA-experienced) in the treatment of CHB.

METHODS

Patients treated between April 2012 and December 2017 were retrospectively studied. A comparison was made between patients treated with ETV in NA-naïve Vs. NA-experienced. Complete virological response (CVR) was defined as achieving undetectable HBV-DNA level, up to 15 IU/ml, partial virological response (PVR) as 15-200 IU/ml and >200 IU/ml for no virological response (NVR) after one year of therapy.

RESULTS

Overall, 148 patients were included (69 NA-naïve and 79 NA-experienced). In NA-naïve group, 51%, 17% and 32% achieved CVR, PVR and NVR vs. 17%, 9% and 75% in NA-experienced group, respectively (p < 0.001). HBsAg seroconversion was achieved in 5.8% in NA-naïve group vs. 6.3% in NA-experienced group (p = 1.00). HBeAg seroconversion was 17% in NA-naïve group and 25% in NA-experienced group (p = 0.24). There was no significant difference in alanine transaminase normalization or in mortality rate between both groups; p = 0.87 and p = 1.00 respectively.

CONCLUSION

ETV therapy in CHB results in a better virological response in NA-naïve patients compared to NA-experienced. There were no differences between both groups in regards to the rate of HBsAg or HBeAg seroconversions, biochemical improvements or mortality.

Nanovaccine for immunotherapy and reduced hepatitis-B virus in humanized model

Chronic Hepatitis B Virus (HBV) infections are severe with weak antiviral immune responses. The lack of an appropriate small animal model for chronic hepatitis, a major hurdle for studying the immunotolerance and immunopathogenesis induced by hepatitis B viral (HBV) infection. In this study, for enhancing the antibody production efficiency the prepared polymeric HBsAg-loaded nanoparticles (nanovaccine) will be tested in immune-deficit mice, which suffer from chronic Hepatitis B virus. Vaccination of Balb/c mice by this prepared nanoparticles that were engrafted with peripheral blood mononuclear cells (PBMCs), which was already lethally irradiated and transplanted by the bone marrow of NOD (knockout mice) mice. In the present study, after the vaccination detected the high frequencies of immunoglobulin G (IgG)-secreting B cells and mitogen-responsive interferon-Y (IFN-Y) secreting T cells in serum, determined by specific ELISA technique. During the entire observation period, unvaccinated animals showed lower concentration of specific IgG secreting B cells and IFN-Y secreting T cells found in comparison to vaccinated mice group. Chronic HBV carrier PBMCs transplanted into the chimera failed to produce antigen and increased the antibodies production due to vaccination. Furthermore, another advantage was that the viral gene expression and viral DNA replication was no longer observed in vaccinated group. This prepared nanovaccine formulations is better for the cure of Hepatitis B viral infection carrier. Therefore, specific memory responses were elicited by vaccination with Hepatitis B virus surface (HBsAg) antigen of chimeric mice transplanted with PBMCs derived from HBV donors.

Post-transplant withdrawal of lamivudine results in fatal hepatitis flares in kidney transplant recipients, under immune suppression, with inactive hepatitis B infection

OBJECTIVE

To evaluate the consequences of lamivudine withdrawal in kidney transplant recipients, under immunosuppression, with inactive hepatitis B virus (HBV) infection.

INTRODUCTION

HBV infection is more frequent in kidney transplant recipients than in the general population mainly due to the high risk of acquisition during dialysis, before kidney transplantation.

METHODS

The records of hepatitis B surface antigen (HBsAg)-positive, immunosuppressed kidney transplant recipients, where lamivudine was withdrawn after transplantation along with reduction in immunosuppressant dose, admitted to our hospital between 2005 and 2012, were retrospectively evaluated.

DISCUSSION

Three patients aged 33, 42 and 33, experienced hepatitis flares 2-3 months after lamivudine withdrawal. Serum HBV DNA levels were 2.5×10⁷, 3.4×10⁴ and 4×10³ IU/ml in cases 1, 2, and 3, respectively. Lamivudine was re-initiated in all cases which led to rapid viral suppression. However, liver function continued to deteriorate leading to severe jaundice, coagulopathy and encephalopathy. All patients died of acute liver failure within six months after the onset of withdrawal hepatitis.

CONCLUSION

Lamivudine should be continued as long as immunosuppressive therapy lasts.

Chronic hepatitis B: Virology, natural history, current management and a glimpse at future opportunities

The host immune system plays an important role in chronic hepatitis B (CHB), both in viral clearance and hepatocellular damage. Advances in our understanding of the natural history of the disease have led to redefining the major phases of infection, with the "high replicative, low inflammatory" phase now replacing what was formerly termed the "immune tolerant" phase, and the "nonreplicative phase" replacing what was formerly termed the "inactive carrier" phase. As opposed to the earlier view that HBV establishes chronic infection by exploiting the immaturity of the neonate's immune system, new findings on trained immunity show that the host is already somewhat "matured" following birth, and is actually very capable of responding immunologically, potentially altering future hepatitis B treatment strategies. While existing therapies are effective in reducing viral load and necroinflammation, often restoring the patient to near-normal health, they do not lead to a cure except in very rare cases and, in many patients, viremia rebounds after cessation of treatment. Researchers are now challenged to devise therapies that will eliminate infection, with a particular focus on eliminating the persistence of viral cccDNA in the nuclei of hepatocytes. In the context of chronic hepatitis B, new definitions of 'cure' are emerging, such as 'functional' and 'virological' cure, defined by stable off-therapy suppression of viremia and antigenemia, and the normalization of serum ALT and other liver-related laboratory tests. Continued advances in the understanding of the complex biology of chronic hepatitis B have resulted in the development of new, experimental therapies targeting viral and host factors and pathways previously not accessible to therapy, approaches which may lead to virological cures in the near term and functional cures upon long term follow-up. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."

Recent advances in micro/nanotechnologies for global control of hepatitis B infection

The control of hepatitis B virus (HBV) infection is a challenging task, specifically in developing countries there is limited access to diagnostics and antiviral treatment mainly due to high costs and insufficient healthcare infrastructure. Although the current diagnostic technologies can reliably detect HBV, they are relatively laborious, impractical and require expensive resources that are not suitable for resource-limited settings. Advances in micro/nanotechnology are pioneering the development of new generation methodologies in diagnosis and screening of HBV. Owing to combination of nanomaterials (metal/inorganic nanoparticles, carbon nanotubes, etc.) with microfabrication technologies, utilization of miniaturized sensors detecting HBV and other viruses from ultra-low volume of blood, serum and plasma is realized. The state-of-the-art microfluidic devices with integrated nanotechnologies potentially allow for inexpensive HBV screening at low cost. This review aims to highlight recent advances in nanotechnology and microfabrication processes that are employed for developing point-of-care (POC) HBV assays.

Retrospective analysis of total direct medical costs associated with hepatitis B patients with oral antiviral versus pegylated interferon therapy in Turkey

To explore healthcare costs associated with antiviral treatment of hepatitis B virus (HBV) in Turkey. Research-identified data from a claims processing system for all Turkish health insurance funds were analysed. Adult patients prescribed oral antiviral and pegylated interferon treatment were identified between 1 January 2010 and 31 December 2010. The first prescription date was defined as the index date. Patients were required to have HBV diagnosis within the 6-month pre-index period. Pharmacy, outpatient and inpatient claims were compiled over the study period for the selected patients, and risk-adjusted 1-year healthcare costs of patients with oral antiviral and pegylated interferon treatment were compared. Risk adjustment was carried out using propensity score matching, controlling for baseline demographic and clinical characteristics. A total of 9618 patients were identified, of which 9074 were treated with oral antiviral medication and 544 with pegylated interferon medication. The oral antiviral treatment group was older (45.28 vs 42.19, P < 0.001), less likely to be female (32.17% vs 39.71%, P < 0.001) and to reside in Southeastern Anatolia (8.29% vs 13.97%, P < 0.001) or Mediterranean region (8.90% vs 11.76%, P < 0.03) and had higher Elixhauser comorbidity index scores (60.22% vs 74.08%, P < 0.001) than the pegylated interferon group. After adjusting for confounding factors, total medical costs for pegylated interferon patients were €2771 higher than for oral antiviral patients (P < 0.001), due to higher outpatient and prescription costs. For annual healthcare costs for antiviral treatment options for HBV patients in Turkey, after adjusting for age, gender, region and comorbid condition differences, oral antiviral treatment is more costly than pegylated interferon treatment.

Virological Response and Muscular Adverse Events during Long-Term Clevudine Therapy in Chronic Hepatitis B Patients

BACKGROUND

Recently, several reports issued clevudine induced myopathy in the long term use.

OBJECTIVES

The aim of this study was to investigate antiviral effects and adverse events of clevudine monotherapy in patients with chronic hepatitis B (CHB).

PATIENTS AND METHODS

The subjects were 110 treatment-naïve CHB patients. They were treated with 30 mg clevudine/day for more than six months. Virological and biochemical tests, including that for serum creatine kinase (CK), were monitored at baseline and at 3-month intervals during treatment period.

RESULTS

In HBeAg-positive patients, the cumulative rates of virological response were 74.0 %, 68.5 %, and 67.3 % after one, two, and three years of clevudine treatment, respectively. Cumulative rates of HBeAg loss or seroconversion were 17.8 %, 30 %, and 31.5 % after one, two and, three years of clevudine treatment, respectively. In HBeAg-negative patients, the cumulative rates of virological response were 97.3 %, 100 %, and 94.6 %, respectively. Virological breakthrough occurred in 27 patients. The rtM204I mutation in HBV polymerase was predominantly detected. Muscular adverse events were observed in 15 patients. All patients with myopathy recovered after the cessation of clevudine monotherapy. Fluctuations in CK level during the clevudine treatment period were frequently observed irrespective of development of myopathy. Multiple episodes of CK elevation were significantly related to the development of myopathy.

CONCLUSIONS

Long-term clevudine monotherapy is effective for suppression of serum HBV DNA level and normalization of serum alanine amino transaminase levels, but associated with occurrence of rtM204I mutation. Clevudine-induced muscular adverse events are not uncommon, although they are totally reversible after cessation of the treatment. Muscular adverse events and serum CK level should be carefully monitored during long-term treatment with clevudine.

Simultaneous determination of metacavir and its metabolites in rat plasma using high-performance liquid chromatography with tandem mass spectrometric detection (LC-MS/MS)

A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of metacavir and its two metabolites in rat plasma was developed and validated. Tinidazole was used as an internal standard and plasma samples were pretreated with one-step liquid-liquid extraction. In addition, these analytes were separated using an isocratic mobile phase on a reverse-phase C18 column and analyzed by MS in the selected reaction monitoring mode. The monitored precursor to product-ion transitions for metacavir, 2',3'-dideoxyguanosine, O-methylguanine and the internal standard were m/z 266.0 → 166.0, m/z 252.0 → 152.0, m/z 166.0 → 149.0 and m/z 248.0 → 202.0, respectively. The standard curves were found to be linear in the range of 1-1000 ng/mL for metacavir, 5-5000 ng/mL for 2',3'-dideoxyguanosine and 1-1000 ng/mL for O-methylguanine in rat plasma. The precision and accuracy for both within- and between-batch determination of all analytes ranged from 2.83 to 9.19% and from 95.86 to 111.27%, respectively. No significant matrix effect was observed. This developed method was successfully applied to an in vivo pharmacokinetic study after a single intravenous dose of 20 mg/kg metacavir in rats.

Unawareness of HBV infection among inpatients in a Southern Italian hospital

Hepatitis B virus (HBV) infection may run undetected. Unawareness of an ongoing infection delays the diagnosis of HBV-related liver disease and favours the spread of the virus. We have evaluated among hepatitis B surface antigen-positive (HBsAg) inpatients admitted to a Southern Italian hospital the proportion of those aware of their carrier status and correlated the status to signs of liver disease. All patients admitted to the San Giovanni Rotondo Hospital from March 2008 to July 2009 were tested for HBV and hepatitis C virus (HCV) markers, and those positive for HBsAg were interviewed and underwent examinations for liver function and abdominal ultrasound. Overall, of 25,000 patients admitted during the observation period 311 (1.2%) were positive for HBsAg, most of them (98%) being anti-HBe positive. HCV and HDV co-infections were ascertained in 2.9% and 0.6% of cases, respectively. Two hundred and fifty-three subjects (81%) agreed to undergo further investigation, 132 of them (52%) were HBV-DNA positive. One hundred and two patients (40.3%) were unaware of their infection; this was encountered among 29% of HBV-DNA-positive and 52% of HBV-DNA-negative subjects (P < 0.01). Subjects already aware of their infection were more likely to present with abnormal alanine aminotransferase (ALT) levels (27%vs 15%), serological presence of HBV-DNA (63.6% vs. 36%) and liver cirrhosis (30%vs. 13%). A high proportion of HBsAg-positive patients (40.3%) were unaware of their infection, which had evolved to the stage of liver cirrhosis in a consistent percentage of them.

Chronic hepatitis B: past, present, and future

There have been major advances in the field of hepatitis B (HBV) over the last few decades. These advances have resulted in the understanding of the natural history of chronic HBV infection, effective vaccines against the virus, sensitive assays for screening and monitoring of treatment, and effective treatments for viral suppression, all leading to improved outcomes. Debates and controversies remain, however, over the ideal management strategies of patients with chronic hepatitis B. To eradicate HBV, the global community needs to improve current preventive, screening, and treatment strategies.

Incidence and determinants of spontaneous hepatitis B surface antigen seroclearance: a community-based follow-up study

BACKGROUND & AIMS

Seroclearance of hepatitis B surface antigen (HBsAg) is one of the most important clinical outcomes for chronic hepatitis B treatment trials. Few studies have explored the incidence and determinants of spontaneous seroclearance using a long-term follow-up study. This study aimed to examine the natural history and predictors of HBsAg seroclearance.

METHODS

A total of 3087 individuals with chronic hepatitis B virus infection were enrolled between 1991 and 1992 in this community-based study. Serum samples collected at baseline and follow-up examinations were tested for HBsAg, hepatitis B e antigen (HBeAg), serum hepatitis B virus (HBV)-DNA levels, and anti-hepatitis C virus serostatus. Cox proportional hazards models were used to estimate HBsAg seroclearance rate ratios associated with various determinants.

RESULTS

HBsAg seroclearance occurred in 562 participants during 24,829 person-years of follow-up evaluation, giving a 2.26% annual seroclearance rate. HBV-DNA levels at baseline and follow-up evaluation were the most significant predictor of seroclearance. Higher HBV viral loads conferred lower HBsAg seroclearance rates (P<.001). A spontaneous decrease in follow-up HBV-DNA level (>or=3 log) was associated significantly with seroclearance, showing an adjusted odds ratio of 4.17 (95% confidence interval, 2.55-6.82). Among those with seroclearance, 95.8% had undetectable HBV-DNA levels before seroclearance. Cumulative incidence of HBsAg seroclearance at 60 and 100 months after serum HBV-DNA level decreased to undetectable was 25.8% and 51.3%, respectively.

CONCLUSIONS

This study reveals determinants of HBsAg seroclearance, and suggests that a low viral load is an important factor affecting the natural seroclearance of HBsAg, indicating significant clinical implications for the treatment of chronic HBV.

Does chemotherapy prevent HBV-related hepatocellular carcinoma? Pros

Studies have shown that hepatitis B virus (HBV) replication is the key driver of disease progression, including development of cirrhosis and hepatocellular carcinoma (HCC), in patients with chronic HBV infection. Among the currently available anti-HBV drugs, the most extensive and longest experience has been gained with conventional interferon alpha (IFN) and lamivudine. Both controlled studies and meta-analyses have shown that a finite course of IFN therapy has long-term benefit in achieving cumulative response and corresponding reduction of cirrhosis and/or HCC. Maintained virological response to lamivudine therapy has similar long-term benefits in reducing disease progression. Although emergence of lamivudine drug resistance may negate therapeutic effect, rescue drugs are now available to overcome the adverse effect of drug resistance. Pegylated IFN and newer nucleos(t)ide analogs may have even better long-term outcomes because of better therapeutic efficacy and/or much lower risk of drug resistances. However, the treatment outcomes are still far from satisfactory. The development of safe and affordable anti-HBV agents/strategies is needed to further improve outcomes.

Drug transporter pharmacogenetics in nucleoside-based therapies

This article focuses on the different types of transporter proteins that have been implicated in the influx and efflux of nucleoside-derived drugs currently used in the treatment of cancer, viral infections (i.e., AIDS) and other conditions, including autoimmune and inflammatory diseases. Genetic variations in nucleoside-derived drug transporter proteins encoded by the gene families SLC15, SLC22, SLC28, SLC29, ABCB, ABCC and ABCG will be specifically considered. Variants known to affect biological function are summarized, with a particular emphasis on those for which clinical correlations have already been established. Given that relatively little is known regarding the genetic variability of the players involved in determining nucleoside-derived drug bioavailability, it is anticipated that major challenges will be faced in this area of research.

On-treatment monitoring of chronic hepatitis B virus infection: an Asian-Pacific perspective

Chronic infection with hepatitis B virus (HBV) is a major global health problem and an important cause of morbidity and mortality from sequelae of liver cirrhosis and hepatocellular carcinoma. In the past decades, better understanding of the natural history and immunopathogenesis of chronic HBV infection and of the development of many powerful antiviral agents has allowed us to improve therapeutic efficacy. Among these agents, nucleos(t)ide analogs are important and potent viral suppressors. However, when administered alone, they are not able to permanently eradicate HBV, and long-term maintenance therapy is required for therapeutic efficacy. Additionally, prolonged treatment is frequently associated with the emergence of drug-resistant HBV mutants. Before an 'ideal' drug(s), or drug combination, with optimal antiviral efficacy and negligible rates of drug resistance becomes available, the on-treatment monitoring approach using serum HBV DNA level as a predictor for therapeutic efficacy and drug resistance is useful. However, most countries in the Asia-Pacific region have low income economies, insufficient medical care systems, and low awareness of the disease among the general population and government officers. The easy approach of the road-map concept using an affordable drug to treat chronic HBV infection is more important in this region. There is already evidence that the long-term outcomes of chronic HBV infection can be improved under well-managed antiviral therapy. Profound and long-lasting suppression of HBV replication, either maintained on-therapy or sustained after stopping therapy, has been identified as the key determinant for achieving the goals of therapy, for reducing liver damage, and for preventing development of cirrhosis and/ or hepatocellular carcinoma.

[Diagnostics and therapy of hepatitis]

In Germany, around 800.000 to 1 million individuals are chronically infected with either the hepatitis B or the hepatitis C virus. Viral hepatitis is therefore highly relevant for the everyday management in clinical practice. For the treatment of hepatitis B, potent antiviral drugs have become available that, in the majority of patients, induce viral suppression. This requires a strategic therapeutic planning in view of a likelihood of long term administration and the prevention of viral resistance. Recent advances in the treatment of hepatitis C are based on a therapeutic individualization based upon viral kinetics and genotypes that also requires strategic planning. In contrast to hepatitis B, viral elimination can be reached in 50-90% of hepatitis C patients. Hepatitis D is associated with a migration background, is most likely under diagnosed and does not yet have a satisfactory curative treatment option. An effective vaccine exists for hepatitis A that offers protection lasting decades. Hepatitis A does not lead to chronic infection. This was also assumed for hepatitis E. However, reports indicate chronic courses in selected patient groups. A vaccine for hepatitis E is currently not yet available.

Antiviral therapy of chronic hepatitis B: opportunities and challenges in Asia

Asia comprises more than 40 countries encompassing a wide geographic area with a very large population. Many of these countries have low-income economies together with high endemicity of chronic hepatitis B virus (HBV) infection, which is usually acquired perinatally or during early childhood. The well elucidated natural history of chronic HBV infection, together with the extensive research and the longest experience in the use of therapeutic agents in Asia have provided a great opportunity for Asian patients to benefit from recent advancements. However, treatment of chronic HBV infection is a complex task that requires individualized assessment, thus representing a great challenge for general physicians. The inherent problems of the drugs currently available, together with a lack of awareness of the disease among patients, government, and healthcare practitioners are obstacles to proper management of HBV. The most critical challenge and obstacle is the high cost of medical care and antiviral drugs. Lack of adequate reimbursement for treatment and diagnostic testing makes adherence to treatment guidelines impossible. Hence lamivudine is still widely used in Asia. To address these challenges, the ongoing awareness campaigns, active screening programs, educational activities are needed but must be enhanced. Cost-cutting measures and international support are essential to improve the difficult situation in this part of the world.

Natural history of chronic hepatitis B virus infection and long-term outcome under treatment

Chronic hepatitis B virus (HBV) infection is a dynamic state of interactions among HBV, the hepatocytes and the immune system of the patient. Perinatally or early childhood-acquired chronic HBV infection has a long 'immune tolerant phase', when patients are young, and HBeAg seropositive with a high viral load but with no significant liver disease. Persistent or episodic liver injuries during the 'immune clearance phase' may lead to decompensation, fibrosis progression or cirrhosis development in some patients, but may eventually lead to HBV-DNA seroclearance with HBeAg seroconversion and entry into the 'inactive phase' with remission. Hepatitis may relapse, because of reactivation of HBV with precore or basal core promptor mutations, and develop 'HBeAg-negative chronic hepatitis', in some patients. In contrast, HBsAg seroclearance may occur in those with sustained remission. During the course, HBV replication is the key driver of disease progression including development of cirrhosis and hepatocellular carcinoma (HCC). Among the currently available anti-HBV drugs, the most extensive and longest experience has been gained with conventional interferon (IFN)-alpha and lamivudine. A finite course of IFN therapy has long-term benefit in achieving a cumulative response, increasing HBsAg seroclearance and reducing cirrhosis and/or HCC. Maintained virological response to lamivudine therapy has a similar long-term benefit in reducing disease progression. Pegylated IFN and newer nucleos(t)ide analogues may have even better long-term outcomes because of better therapeutic efficacy and/or a low risk of drug resistances. The treatment outcomes are still far from satisfactory. The development of safe and affordable anti-HBV agents/strategies is needed to further improve outcomes.