Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference

Contriving a novel of CHB therapeutic vaccine based on IgV_CTLA-4 and L protein via immunoinformatics approach

Chronic infection induced by immune tolerance to hepatitis B virus (HBV) is one of the most common causes of hepatic cirrhosis and hepatoma. Fortunately, the application of therapeutic vaccine can not only reverse HBV-tolerance, but also serve a potentially effective therapeutic strategy for treating chronic hepatitis B (CHB). However, the clinical effect of the currently developed CHB therapeutic vaccine is not optimistic due to the weak immunogenicity. Given that the human leukocyte antigen CTLA-4 owns strong binding ability to the surface B7 molecules (CD80 and CD86) of antigen presenting cell (APCs), the immunoglobulin variable region of CTLA-4 (IgV_CTLA-4) was fused with the L protein of HBV to contrive a novel therapeutic vaccine (V_C4HBL) for CHB in this study. We found that the addition of IgV_CTLA-4 did not interfere with the formation of L protein T cell and B cell epitopes after analysis by means of immunoinformatics approaches. Meanwhile, we also found that the IgV_CTLA-4 had strong binding force to B7 molecules through molecular docking and molecular dynamics (MD) simulation. Notably, our vaccine V_C4HBL showed good immunogenicity and antigenicity by in vitro and in vivo experiments. Therefore, the V_C4HBL is promising to again effectively activate the cellular and humoral immunity of CHB patients, and provides a potentially effective therapeutic strategy for the treatment of CHB in the future.Communicated by Ramaswamy H. Sarma.

Characteristics analysis of hepatitis B core-related antigen in children with hepatitis B e antigen-positive chronic viral hepatitis B infection

BACKGROUND

The objective of antiviral therapy for chronic viral hepatitis B infection (CHB) is to achieve a functional cure. An important viral marker in the serum of patients with CHB is the serum hepatitis B core-related antigen (HBcrAg). However, there is limited research on HBcrAg in juvenile patients with CHB. In this study, we aimed to investigate the correlation between serum HBcrAg and other hepatitis B virus (HBV) markers in children with CHB and its predictive significance for prognosis during antiviral therapy.

METHODS

A single-center retrospective study was conducted involving 79 children with CHB, aged between 0 and 16 years. All the children were treated with interferon [or combined nucleos(t)ide analogs] for 48 weeks. HBcrAg, hepatitis B surface antigen (HBsAg), and HBV DNA were measured before treatment, and at 12 and 48 weeks after treatment. The enrolled children were classified into the seroclearance group and the nonseroclearance group based on the therapeutic outcome.

RESULTS

HBsAg seroclearance was observed in 28 out of 79 patients and hepatitis B e antigen seroconversion without HBsAg seroclearance was observed in 14 out of 79 patients following the conclusion of the treatment, with baseline HBcrAg titer levels showing no statistical significance in both the seroclearance and nonseroclearance groups (P = 0.277). HBsAg and HBV DNA were positively correlated with HBcrAg in children with CHB (R2 = 0.3289, 0.4388). The area under the receiver operating characteristic curve of the decrease in HBcrAg at 12 weeks of treatment as a predictor of seroclearance at 48 weeks of treatment, exhibited a value of 0.77.

CONCLUSION

A decrease in serum HBcrAg levels in children with hepatitis B serves as a prognostic indicator.

Optimized RNA interference therapeutics combined with interleukin-2 mRNA for treating hepatitis B virus infection

This study aimed to develop a pan-genotypic and multifunctional small interfering RNA (siRNA) against hepatitis B virus (HBV) with an efficient delivery system for treating chronic hepatitis B (CHB), and explore combined RNA interference (RNAi) and immune modulatory modalities for better viral control. Twenty synthetic siRNAs targeting consensus motifs distributed across the whole HBV genome were designed and evaluated. The lipid nanoparticle (LNP) formulation was optimized by adopting HO-PEG2000-DMG lipid and modifying the molar ratio of traditional polyethylene glycol (PEG) lipid in LNP prescriptions. The efficacy and safety of this formulation in delivering siHBV (tLNP/siHBV) along with the mouse IL-2 (mIL-2) mRNA (tLNP/siHBVIL2) were evaluated in the rAAV-HBV1.3 mouse model. A siRNA combination (terms "siHBV") with a genotypic coverage of 98.55% was selected, chemically modified, and encapsulated within an optimized LNP (tLNP) of high efficacy and security to fabricate a therapeutic formulation for CHB. The results revealed that tLNP/siHBV significantly reduced the expression of viral antigens and DNA (up to 3log10 reduction; vs PBS) in dose- and time-dependent manners at single-dose or multi-dose frequencies, with satisfactory safety profiles. Further studies showed that tLNP/siHBVIL2 enables additive antigenic and immune control of the virus, via introducing potent HBsAg clearance through RNAi and triggering strong HBV-specific CD4+ and CD8+ T cell responses by expressed mIL-2 protein. By adopting tLNP as nucleic acid nanocarriers, the co-delivery of siHBV and mIL-2 mRNA enables synergistic antigenic and immune control of HBV, thus offering a promising translational therapeutic strategy for treating CHB.

Latest insights into the epidemiology, characteristics, and therapeutic strategies of chronic hepatitis B patients in indeterminate phase

As a hepatotropic virus, hepatitis B virus (HBV) can establish a persistent chronic infection in the liver, termed, chronic hepatitis B (CHB), which causes a series of liver-related complications, including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HCC with HBV infection has a significantly increased morbidity and mortality, whereas it could be preventable. The current goal of antiviral therapy for HBV infection is to decrease CHB-related morbidity and mortality, and achieve sustained suppression of virus replication, which is known as a functional or immunological cure. The natural history of chronic HBV infection includes four immune phases: the immune-tolerant phase, immune-active phase, inactive phase, and reactivation phase. However, many CHB patients do not fit into any of these defined phases and are regarded as indeterminate. A large proportion of indeterminate patients are only treated with dynamic monitoring rather than recommended antiviral therapy, mainly due to the lack of definite guidelines. However, many of these patients may gradually have significant liver histopathological changes during disease progression. Recent studies have focused on the prevalence, progression, and carcinogenicity of indeterminate CHB, and more attention has been given to the prevention, detection, and treatment for these patients. Herein, we discuss the latest understanding of the epidemiology, clinical characteristics, and therapeutic strategies of indeterminate CHB, to provide avenues for the management of these patients.

Perspective on Emerging Therapies to Achieve Functional Cure of Chronic Hepatitis B

Purpose of Review

Advancements in our understanding of the hepatitis B viral (HBV) life cycle have paved the way for novel approaches to treat HBV infection. This review summarizes the various strategies being pursued to achieve a functional cure, defined as loss of hepatitis B surface antigen (HBsAg) and absence of viral replication 6 months off-therapy.

Recent Findings

Direct acting antiviral, host targeting antiviral, and immunological approaches are in various stages of development as treatment for chronic HBV infection.

Summary

Novel treatments are being developed in pursuit of a cure for HBV. Current evidence suggests a single therapeutic agent alone may be insufficient, necessitating the need for combination therapy targeting HBV and the host immune response. Ongoing research focused on identifying the best therapeutic combination holds promise in achieving functional cure for HBV.

Measuring HBV pregenomic RNA may be a potential biomarker to determine HBV functional cure in HIV/HBV-co-infected patients with HBsAg loss

Functional cure of hepatitis B virus (HBV) is an optimal treatment goal for chronic hepatitis B, with the loss of hepatitis B surface antigen (HBsAg) being a crucial indicator. However, the adequacy of HBsAg loss for evaluating functional cure of HBV in patients co-infected with HBV/human immunodeficiency virus (HIV) remains controversial. In this study, we measured HBV pregenomic RNA (pgRNA), a potential biomarker that correlates with covalently closed circular DNA, in the frozen plasma of 98 patients with HBsAg loss from a large HIV/HBV co-infection cohort in Guangzhou, China. HBV pgRNA was still detected in 43.9% (44/98) of the patients, suggesting active HBV replication in individuals with HBsAg loss. Our observations imply that HBsAg loss may not be a reliable predictor of HBV functional cure in cases of HIV/HBV co-infection.

Long-term open-label vebicorvir for chronic HBV infection: Safety and off-treatment responses

Background & Aims

The investigational first-generation core inhibitor vebicorvir (VBR) demonstrated safety and antiviral activity over 24 weeks in two phase IIa studies in patients with chronic HBV infection. In this long-term extension study, patients received open-label VBR with nucleos(t)ide reverse transcriptase inhibitors (NrtIs).

Methods

Patients in this study (NCT03780543) previously received VBR + NrtI or placebo + NrtI in parent studies 201 (NCT03576066) or 202 (NCT03577171). After receiving VBR + NrtI for ≥52 weeks, stopping criteria (based on the treatment history and hepatitis B e antigen status in the parent studies) were applied, and patients either discontinued both VBR + NrtI, discontinued VBR only, or continued both VBR + NrtI. The primary efficacy endpoint was the proportion of patients with HBV DNA <20 IU/ml at 24 weeks off treatment.

Results

Ninety-two patients entered the extension study and received VBR + NrtI. Long-term VBR + NrtI treatment led to continued suppression of HBV nucleic acids and, to a lesser extent, HBV antigens. Forty-three patients met criteria to discontinue VBR + NrtI, with no patients achieving the primary endpoint; the majority of virologic rebound occurred ≥4 weeks off treatment. Treatment was generally well tolerated, with few discontinuations due to adverse events (AEs). There were no deaths. Most AEs and laboratory abnormalities were related to elevations in alanine aminotransferase and occurred during the off-treatment or NrtI-restart phases. No drug-drug interactions between VBR + NrtI and no cases of treatment-emergent resistance among patients who adhered to treatment were observed.

Conclusions

Long-term VBR + NrtI was safe and resulted in continued reductions in HBV nucleic acids following completion of the 24-week parent studies. Following treatment discontinuation, virologic relapse was observed in all patients. This first-generation core inhibitor administered with NrtI for at least 52 weeks was not sufficient for HBV cure.

Clinical trial number

NCT03780543.

Impact and implications

Approved treatments for chronic hepatitis B virus infection (cHBV) suppress viral replication, but viral rebound is almost always observed after treatment discontinuation, highlighting an unmet need for improved therapies with finite treatment duration producing greater therapeutic responses that can be sustained off treatment. First-generation core inhibitors, such as vebicorvir, have mechanisms of action orthogonal to standard-of-care therapies that deeply suppress HBV viral replication during treatment; however, to date, durable virologic responses have not been observed after treatment discontinuation. The results reported here will help researchers with the design and interpretation of future studies investigating core inhibitors as possible components of finite treatment regimens for patients with cHBV. It is possible that next-generation core inhibitors with enhanced potency may produce deeper and more durable antiviral activity than first-generation agents, including vebicorvir.

Advances in discovery of novel investigational agents for functional cure of chronic hepatitis B: A comprehensive review of phases II and III therapeutic agents

Chronic hepatitis B virus (HBV) infection affects over 295 million people globally and an estimated 1.6 million people in the United States. It is associated with significant morbidity and mortality due to cirrhosis, liver failure, and liver cancer. Antiviral therapy with oral nucleos(t)ide analogues is associated with high rates of virologic suppression, which in turn has been associated with a decreased risk of liver complications. However, current antiviral regimens are limited by concerns with adverse effects, adherence, resistance, long-term treatment, and ongoing risk for liver events. Novel investigational agents are currently in development and are targeted at achieving functional cure with sustained hepatitis B surface antigen (HBsAg) loss and suppression of HBV DNA. Herein we review key evidence from phases II and III trials defining the efficacy and safety profiles for key investigational agents for functional cure of chronic hepatitis B, including core/capsid inhibitors, entry inhibitors, RNA interference (siRNA/ASO), HBsAg inhibitors, Toll-like receptor agonists, checkpoint inhibitors, and therapeutic vaccines.

Understanding the Natural History of Chronic Hepatitis D: Proposal of a Model for Cost-Effectiveness Studies

BACKGROUND

As new therapeutic options become available, better understanding the potential impact of emerging therapies on clinical outcomes of hepatits D virus (HDV) is critical.

OBJECTIVE

The aim of this study was to develop a natural history model for patients with hepatitis D virus.

METHODS

We developed a model (decision tree followed by a Markov cohort model) in adults with chronic HDV infection to assess the natural history and impact of novel treatments on disease progression versus best supportive care (BSC). The model time horizon was over a lifetime (up to 100 years of age); state transitions and health states were defined by responder status. Patients in fibrosis stages 0 through 4 received treatment; decompensated patients were not treated. Response was defined as the combined response endpoint of achievement of HDV-RNA undetectability/≥2-log10 decline and alanine aminotransferase normalization; response rates of 50% and 75% were explored. Health events associated with advanced liver disease were modeled as the number of events per 10,000 patients. Scenario analyses of early treatment, alternate treatment response, and no fibrosis regression for treatment responders were also explored.

RESULTS

The model was able to reflect disease progression similarly to published natural history studies for patients with HBV/HDV infection. In a hypothetical cohort of patients reflecting a population enrolled in a recent clinical trial, fewer advanced liver disease events were observed with a novel HDV treatment versus BSC. Fewer liver-related deaths were observed under 50% and 75% response (900 and 1,358 fewer deaths, respectively, per 10,000 patients). Scenario analyses showed consistently fewer advanced liver disease events with HDV treatment compared with BSC, with greater reductions observed with earlier treatment.

CONCLUSION

This HDV disease progression model replicated findings from natural history studies. Furthermore, it found that a hypothetical HDV treatment results in better clinical outcomes for patients versus BSC, with greater benefit observed when starting treatment early. This validated natural history model for HBV/HDV infection can serve as a foundation for future clinical and economic analyses of novel HDV treatments that can support healthcare stakeholders in the management of patients with chronic HDV.

Safety, pharmacodynamics, and antiviral activity of selgantolimod in viremic patients with chronic hepatitis B virus infection

Background & Aims

Novel finite therapies for chronic hepatitis B (CHB) are needed, since lifelong treatment is usually required with current available oral antivirals. This phase II study (NCT03615066) evaluated the safety, pharmacodynamics, and antiviral activity of selgantolimod (a Toll-like receptor 8 agonist [TLR8]) with tenofovir alafenamide (TAF).

Methods

Viremic patients with CHB not receiving treatment were stratified by HBeAg status and randomized 2:2:1 to TAF 25 mg/day with selgantolimod 3 mg orally once weekly (QW), selgantolimod 1.5 mg QW, or placebo. Combination therapy continued until week (W)24, followed by TAF monotherapy until W48; patients then discontinued TAF and were followed until W96 (treatment-free follow-up [TFFU] period). The primary efficacy endpoint was the proportion with ≥1 log10 IU/ml HBsAg decline at W24.

Results

Sixty-seven patients received study drug; 27 were followed during TFFU. Nausea, headache, vomiting, fatigue, and dizziness were the most common adverse events. Most adverse events were grade 1. Alanine aminotransferase flares were not observed up to W48. Four patients experienced alanine aminotransferase and hepatitis flares during TFFU; all had HBV DNA increases. Selgantolimod increased serum cytokines and chemokines and redistributed several circulating immune cell subsets. No patients achieved the primary efficacy endpoint. Mean HBsAg changes were -0.12, -0.16, and -0.12 log10 IU/ml in the selgantolimod 3 mg, selgantolimod 1.5 mg, and placebo groups, respectively, at W48; HBV DNA declined in all groups by ≥2 log10 IU/ml as early as W2, with all groups rebounding to baseline during TFFU. No HBsAg or HBeAg loss or seroconversion was observed throughout TFFU.

Conclusions

Selgantolimod up to 3 mg was safe and well tolerated. Pharmacodynamics and antiviral activity in viremic patients support continued study of selgantolimod in combination CHB therapies.

Impact and implications

Novel therapeutics for chronic HBV infection are needed to achieve a functional cure. In this study, we confirmed the safety and tolerability of selgantolimod (formerly GS-9688, a TLR8) when administered with tenofovir alafenamide over 24 weeks in viremic patients with chronic HBV infection. Overall, declines in HBsAg levels with selgantolimod treatment were modest; subgroup analysis indicated that patients with alanine aminotransferase levels greater than the upper limit of normal had significantly greater declines compared to those with normal alanine aminotransferase levels (-0.20 vs. -0.03 log10 IU/ml; p <0.001). These findings suggest a potential differential response to selgantolimod based on patients' baseline HBV-specific immune response, which should be considered in future investigations characterizing the underlying mechanisms of selgantolimod treatment and in HBV cure studies using similar immunomodulatory pathways.

Clinical trial number

NCT03615066 be found at https://www.gileadclinicaltrials.com/transparency-policy/.

Clinical long-term outcome of hepatitis D compared to hepatitis B monoinfection

BACKGROUND AND AIMS

Hepatitis D virus (HDV) infection causes the most severe form of chronic viral hepatitis. However, it is still unclear to what extent the underlying cirrhosis may contribute to disease progression. The aim of this study was to compare the long-term outcome of HDV infection with HBV monoinfection in a single-center cohort of both non-cirrhotic and cirrhotic patients.

METHOD

We retrospectively studied 175 patients with chronic hepatitis D (CHD) who were followed for at least 6 months (median of 6.3 (0.6-23.6) years). In addition, we selected 175 patients with HBV monoinfection (CHB) who were matched for gender, age, region of origin, HBeAg status, and bilirubin. Liver-related clinical end points were defined as hepatic decompensation (ascites, encephalopathy, variceal bleeding), liver transplantation, HCC, or liver-related death.

RESULTS

Clinical complications developed earlier (4.6 vs. 6.2 years) and more frequently (35.4% vs. 12.6%, p < 0.01) in CHD patients. In a multivariate Cox regression, HDV infection was independently associated with the development of end points (p < 0.01; HR: 3.0; 95% CI 1.4-6.4). However, in cirrhotic patients there were no significant differences between HBV and HDV in the development of end points. Besides, CHB patients with cirrhosis developed more frequently HCC (35.5%) than CHD patients with cirrhosis (18.5%).

CONCLUSION

Our results confirmed that HDV leads to a faster progression to cirrhosis compared to HBV. However, once cirrhosis is present, not HDV but the underlying cirrhosis is the dominate intrinsic risk factor for the development of liver-related end points and for the progression to HCC.

Hepatitis D virus infection: Pathophysiology, epidemiology and treatment. Report from the first international delta cure meeting 2022

Chronic infection with hepatitis delta virus (HDV) affects between 12-20 million people worldwide and represents the most severe form of viral hepatitis, leading to accelerated liver disease progression, cirrhosis and its complications, such as end-stage-liver disease and hepatocellular carcinoma. From the discovery of HDV in 1977 by Prof. Mario Rizzetto, knowledge on the HDV life cycle and mechanisms of viral spread has expanded. However, little is still known about the natural history of the disease, host-viral interactions, and the role of the immune system in HDV persistence. Diagnosis of HDV is still challenging due to a lack of standardised assays, while accurate viral load quantification is needed to assess response and endpoints of antiviral treatment. Until recently, interferon has represented the only treatment option in patients with chronic hepatitis delta; however, it is associated with low efficacy and a high burden of side effects. The discovery of the entry inhibitor bulevirtide has represented a breakthrough in HDV treatment, by demonstrating high rates of viral suppression in phase II and III trials, results which have been confirmed in real-world settings and in patients with compensated advanced liver disease. In the meantime, other compounds (i.e. lonafarnib, new anti-hepatitis B virus drugs) are under development to provide alternative or combined strategies for HDV cure. The first international Delta Cure meeting was organised in Milan in October 2022 with the aim of sharing and disseminating the latest data; this review summarises key takeaway messages from state-of-the-art lectures and research data on HDV.

Design and analysis considerations for early phase clinical trials in hepatitis B (HBV) cure research: the ACTG A5394 study in persons with both HIV and HBV

With growing interest and efforts to achieve a hepatitis B (HBV) cure, HBV therapeutics have increasingly entered the clinical testing phase. In designing an early phase clinical trial aimed at HBV cure, the heterogeneity in participants and the choice of a biomarker endpoint that signals a cure requires careful consideration. We describe the key elements to consider during the development of HBV clinical trials aimed at a functional cure, and how we have addressed them in the design of a phase II AIDS Clinical Trials Group (ACTG) study, A5394 (NCT05551273). The trial we present is for persons with both HIV and HBV, a unique population that has much to gain from an HBV cure. Our decisions on the design elements are specific to the study agent and the targeted population, but our deliberations may be informative in the emerging field of early phase HBV trials aimed at cure.

Chronic Hepatitis B Infection: New Approaches towards Cure

Chronic hepatitis B virus (HBV) infection leads to the development of cirrhosis and hepatocellular carcinoma. Lifelong treatment with nucleotides/nucleoside antiviral agents is effective at suppressing HBV replication, however, adherence to daily therapy can be challenging. This review discusses recent advances in the development of long-acting formulations for HBV treatment and prevention, which could potentially improve adherence. Promising new compounds that target distinct steps of the virus life cycle are summarized. In addition to treatments that suppress viral replication, curative strategies are focused on the elimination of covalently closed circular DNA and the inactivation of the integrated viral DNA from infected hepatocytes. We highlight promising long-acting antivirals and genome editing strategies for the elimination or deactivation of persistent viral DNA products in development.

Impact of the Route and Schedule of Immunization on the Serological and Virological Response of Chronic Hepatitis B Patients Treated with HeberNasvac

HeberNasvac is a recently developed therapeutic vaccine for chronic hepatitis B (CHB) administered by intranasal (IN) and subcutaneous (SC) routes in a 14 days/10 doses schedule. To compare different schedules and routes of immunizations, a group of patients received four different vaccination regimens in a placebo-controlled factorial study. Subsequently, patients were followed for a minimum time of 48 weeks. Samples collected at the end of the follow-up were compared with initial samples. Groups I and II received the product by IN/SC routes, every 14 and 7 days, respectively. Groups III and IV were treated by SC route alone following a 14 and 7 days schedule. A group of 21 CHB patients received the vaccine in four different schedules and eight patients received placebo for a total of 29 patients enrolled. The 61.9% of vaccinees reduced their VL ≥2Log compared with baseline levels and 25% in placebo group. The 47.6% of vaccines reduced HBV levels to undetectable, 25% in placebo. HBeAg loss and seroconversion to anti-HBeAg was only achieved in vaccinees, 4 out of 9 (44.4%), and 40% (8 out of 20) developed anti-HBs response, none in placebo group. Reduction of HBsAg level in ≥1Log was achieved in the 35.0% of vaccinees and in none of the placebo-treated patients. Considering the individual and factorial analysis, significant HBV DNA reduction was detected in groups I and II, immunized by IN/SC routes. A significantly higher proportion of patients reducing VL to ≥2Log was also detected grouping the patients treated by IN/SC routes (G I + II) and grouping those inoculated every 14 days (G I + III), with 72.7% and 63.6%, respectively, compared with the placebo group (25.0%). The patients immunized every 14 days (G I + G III) also reduced the HBsAg levels compared with baseline. In conclusion, after more than 48 weeks of treatment-free follow-up, HeberNasvac-treated patients demonstrated superior responses compared with the placebo group in terms of antiviral and serological responses. The factorial analysis evidenced that the schedule combining the IN route of immunization and the frequency of 14 days resulted in the stronger antiviral and serological responses. Present results support the study of IN-only immunization schedules in future and was consistent with previous results. Long-lasting follow-ups were done to explore histological variables and the progression of serological variables in order to detect late responders.

How to cite this article

Freyre FM, Aguiar JA, Cinza Z, et al. Impact of the Route and Schedule of Immunization on the Serological and Virological Response of Chronic Hepatitis B Patients Treated with HeberNasvac. Euroasian J Hepato-Gastroenterol 2023;13(2):73-78.

Current and novel modalities for management of chronic hepatitis B infection

Over 296 million people are estimated to have chronic hepatitis B viral infection (CHB), and it poses unique challenges for elimination. CHB is the result of hepatitis B virus (HBV)-specific immune tolerance and the presence of covalently closed circular DNA as mini chromosome inside the nucleus and the integrated HBV. Serum hepatitis B core-related antigen is the best surrogate marker for intrahepatic covalently closed circular DNA. Functional HBV “cure” is the durable loss of hepatitis B surface antigen (HBsAg), with or without HBsAg seroconversion and undetectable serum HBV DNA after completing a course of treatment. The currently approved therapies are nucleos(t)ide analogues, interferon-alpha, and pegylated-interferon. With these therapies, functional cure can be achieved in < 10% of CHB patients. Any variation to HBV or the host immune system that disrupts the interaction between them can lead to reactivation of HBV. Novel therapies may allow efficient control of CHB. They include direct acting antivirals and immunomodulators. Reduction of the viral antigen load is a crucial factor for success of immune-based therapies. Immunomodulatory therapy may lead to modulation of the host immune system. It may enhance/restore innate immunity against HBV (as toll-like-receptors and cytosolic retinoic acid inducible gene I agonist). Others may induce adaptive immunity as checkpoint inhibitors, therapeutic HBV vaccines including protein (HBsAg/preS and hepatitis B core antigen), monoclonal or bispecific antibodies and genetically engineered T cells to generate chimeric antigen receptor-T or T-cell receptor-T cells and HBV-specific T cells to restore T cell function to efficiently clear HBV. Combined therapy may successfully overcome immune tolerance and lead to HBV control and cure. Immunotherapeutic approaches carry the risk of overshooting immune responses causing uncontrolled liver damage. The safety of any new curative therapies should be measured in relation to the excellent safety of currently approved nucleos(t)ide analogues. Development of novel antiviral and immune modulatory therapies should be associated with new diagnostic assays used to evaluate the effectiveness or to predict response.

A prodrug of the capsid assembly modulator improved druggability and lowing HBsAg and HBeAg for the treatment of chronic hepatitis B

CAMs were disclosed to alter cccDNA levels with sustained hepatitis B surface antigen (HBsAg) loss or seroconversion in preclinical investigation. Here, we report the discovery of a prodrug Yhhu6669 as CAMs based on the intestinal peptide transporter. This compound exhibited the promising anti-HBV activity with sustained suppression of HBV DNA, as well as HBsAg and HBeAg in the AAV HBV mouse model by oral treatment for 7 weeks and maintained for a further 8 weeks following drug withdraw. Our results show an alternative possibility for a functional cure by specific CAMs and provide the basis for the further mechanism study.

Advances in determining new treatments for hepatitis B infection by utilizing existing and novel biomarkers

INTRODUCTION

Chronic hepatitis B (CHB) infection is a major global health threat and accounts for significant liver-related morbidity and mortality. An improved understanding of how hepatitis B virus (HBV) interacts with the host immune system allows the discovery of novel biomarkers and new treatment options. Viral biomarkers including hepatitis B surface antigen (HBsAg) and newer ones like HBV RNA and hepatitis B core-related antigen appear to be useful to select patients who are likely to benefit from cessation of long-term antiviral therapy. These markers can also help to confirm target engagement for novel compounds, and efficacy in HBsAg reduction and seroclearance is deemed essential as this is how the current treatment endpoint of functional cure is defined.

AREAS COVERED

In this review, the authors discuss the current standard of care and the gaps between such standard and the ideal goals for treatment in CHB. The authors highlight novel viral and immunological biomarkers that are potentially useful to evaluate treatment response. Novel treatment approaches in relation to these novel biomarkers are also evaluated.

EXPERT OPINION

Novel serum viral biomarkers and immunological markers are indispensable in the HBV functional cure program. These will likely become part of standard monitoring soon.

Safety, pharmacokinetics and antiviral activity of ABI-H2158, a hepatitis B virus core inhibitor: A randomized, placebo-controlled phase 1 study

Treatment for chronic hepatitis B virus infection (cHBV) is mostly indefinite, with new finite-duration therapies needed. We report safety, pharmacokinetics and antiviral activity of the investigational HBV core inhibitor ABI-H2158. This Phase 1a/b study (NCT03714152) had three parts: Part A, participants received a single ascending oral dose of ABI-H2158 (5-500 mg) or placebo; Part B, participants received multiple doses of ABI-H2158 300 mg once (QD) or twice (BID) daily or placebo, for 10 days; Part C, cHBV patients received ABI-H2158 (100, 300, or 500 mg QD or 300 mg BID) or placebo, for 14 days. Ninety-three participants enrolled. In Parts A/B, there were no serious adverse events (SAEs) or deaths, and all treatment-emergent AEs (TEAEs) were Grade 1. In Part C, two patients had Grade 3 TEAEs unrelated to ABI-H2158; there were no deaths, SAEs or Grade 4 TEAEs. In Part A, median time to maximum ABI-H2158 plasma concentration (T_max ) and mean terminal elimination half-life (t_½ ) were 1-4 and 9.8-20.7 h, and area under the plasma concentration-time curve increased dose proportionally. In Part B, Day 10 T_max was 2 h, mean t_½ was 15.5-18.4 h, and exposure accumulated 1.7- to 3.1-fold. In Part C, Day 14 T_max was 1 h, exposure accumulated 1.4- to 1.8-fold, and ABI-H2158 was associated with >2 log₁₀ declines in HBV nucleic acids. In conclusion, ABI-H2158 in cHBV patients following 14 days of dosing was well tolerated and demonstrated potent antiviral activity. Safety and pharmacokinetics supported future QD dosing.

The scientific basis of combination therapy for chronic hepatitis B functional cure

Functional cure of chronic hepatitis B (CHB) - or hepatitis B surface antigen (HBsAg) loss after 24 weeks off therapy - is now the goal of treatment, but is rarely achieved with current therapy. Understanding the hepatitis B virus (HBV) life cycle and immunological defects that lead to persistence can identify targets for novel therapy. Broadly, treatments fall into three categories: those that reduce viral replication, those that reduce antigen load and immunotherapies. Profound viral suppression alone does not achieve quantitative (q)HBsAg reduction or HBsAg loss. Combining nucleos(t)ide analogues and immunotherapy reduces qHBsAg levels and induces HBsAg loss in some patients, particularly those with low baseline qHBsAg levels. Even agents that are specifically designed to reduce viral antigen load might not be able to achieve sustained HBsAg loss when used alone. Thus, rationale exists for the use of combinations of all three therapy types. Monitoring during therapy is important not just to predict HBsAg loss but also to understand mechanisms of HBsAg loss using viral and immunological biomarkers, and in selected cases intrahepatic sampling. We consider various paths to functional cure of CHB and the need to individualize treatment of this heterogeneous infection until a therapeutic avenue for all patients with CHB is available.

Hepatitis B virus pre-genomic RNA and hepatitis B core-related antigen reductions at week 4 predict favourable hepatitis B surface antigen response upon long-term nucleos(t)ide analogue in chronic hepatitis B

BACKGROUND/AIMS

We investigated the dynamics of serum HBV pre-genomic RNA (pgRNA) and hepatitis B core-related antigen (HBcrAg) in patients receiving nucleos(t)ide analogues (NAs) and their predictability for favourable suppression of serum hepatitis B surface antigen (HBsAg).

METHODS

Serum viral biomarkers were measured at baseline, weeks 4, 12, 24, 36, and 48 of treatment. Patients were followed up thereafter and serum HBsAg level was measured at end of follow-up (EOFU). Favourable HBsAg response (FHR) was defined as ≤100 IU/mL or HBsAg seroclearance upon EOFU.

RESULTS

Twenty-eight hepatitis B e antigen (HBeAg)-positive and 36 HBeAg-negative patients (median, 38.2 years old; 71.9% male) were recruited with median follow-up duration of 17.1 years (interquartile range, 12.8-18.2). For the entire cohort, 22/64 (34.4%) achieved FHR. For HBeAg-positive patients, serum HBV pgRNA decline at week 4 was significantly greater for patients with FHR compared to non-FHR (5.49 vs. 4.32 log copies/mL, respectively; P=0.016). The area under the receiver-operating-characteristic curve (AUROC) for week 4 HBV pgRNA reduction to predict FHR in HBeAg-positive patients was 0.825 (95% confidence interval [CI], 0.661-0.989). For HBeAg-negative patients, instead of increase in serum HBcrAg in non-FHR patients, FHR patients had median reduction in HBcrAg at week 4 (increment of 1.75 vs. reduction of 2.98 log U/mL; P=0.023). The AUROC for week 4 change of HBcrAg to predict FHR in HBeAg-negative patients was 0.789 (95% CI, 0.596-0.982).

CONCLUSION

Early on-treatment changes of serum HBV pgRNA and HBcrAg at 4 weeks predict HBsAg seroclearance or ≤100 IU/mL in NA-treated CHB patients upon long-term FU.

Current Best Practice in Hepatitis B Management and Understanding Long-term Prospects for Cure

The hepatitis B virus (HBV) is a major cause of cirrhosis and hepatocellular carcinoma worldwide. Despite an effective vaccine, the prevalence of chronic infection remains high. Current therapy is effective at achieving on-treatment, but not off-treatment, viral suppression. Loss of hepatitis B surface antigen, the best surrogate marker of off-treatment viral suppression, is associated with improved clinical outcomes. Unfortunately, this end point is rarely achieved with current therapy because of their lack of effect on covalently closed circular DNA, the template of viral transcription and genome replication. Major advancements in our understanding of HBV virology along with better understanding of immunopathogenesis have led to the development of a multitude of novel therapeutic approaches with the prospect of achieving functional cure (hepatitis B surface antigen loss) and perhaps complete cure (clearance of covalently closed circular DNA and integrated HBV DNA). This review will cover current best practice for managing chronic HBV infection and emerging novel therapies for HBV infection and their prospect for cure.

Current treatment of chronic hepatitis B: Clinical aspects and future directions

Hepatitis B virus (HBV) infection is a public health threat worldwide, and there is no direct treatment yet available. In the event of infection, patients may present liver cirrhosis and cancer, which threaten the patients’ health globally, especially in the Asia-Pacific region and China. In 2019, Chinese hepatopathologists updated the 2015 Guidelines for the Prevention and Treatment of Chronic Hepatitis B as the clinical reference. The other versions formulated by the American Association for the Study of Liver Diseases (2018 AASLD guidelines) (AASLD, 2018), European Association for the Study of the Liver (2017 EASL guidelines) (EASL, 2017), and Asian-Pacific Association for the Study of the Liver (2015 APASL guidelines) (APASL, 2015) also provide clinical guidance. However, there are still some issues that need to be addressed. In the present study, the following aspects will be introduced successively: (1) Who should be treated in the general population according to the guidelines; (2) Treatment of specific populations infected with HBV; (3) Controversial issues in clinical practice; (4) Perspective.

TRIM26 inhibits hepatitis B virus replication by promoting HBx degradation and TRIM26 genetic polymorphism predicts PegIFNα treatment response of HBeAg-positive chronic hepatitis B Patients

BACKGROUND

Hepatitis B virus (HBV) infection is a serious global health burden. TRIM26 has been reported to affect hepatitis C virus replication.

AIMS

To manifest the role of TRIM26 on HBV replication and explore if there are single-nucleotide polymorphisms (SNPs) in TRIM26 associated with response to pegylated interferon-alpha (PegIFNα) treatment in patients with chronic hepatitis B (CHB).

METHODS

We investigated the effect and mechanism of TRIM26 on HBV replication in vitro. The association between SNPs in TRIM26 and PegIFNα treatment response was evaluated in two independent cohorts including 238 and 707 patients with HBeAg-positive CHB.

RESULTS

Knockdown of TRIM26 increased, while overexpression of TRIM26 inhibited, HBV replication. Co-immunoprecipitation assays and immunofluorescence showed that TRIM26 interacted and co-localised with HBx. Co-transfection of HBx-HIS and TRIM26-FLAG plasmids in Huh7 cells showed that TRIM26 inhibited the expression of HBx. Furthermore, TRIM26 inhibited HBV replication by mediating HBx ubiquitination degradation, and TRIM26 SPRY domain was responsible for the interaction and degradation of HBx. Besides, IFN increased TRIM26 expression. TRIM26 rs116806878 was associated with response to PegIFNα in two CHB cohorts. Moreover, a polygenic score integrating TRIM26 rs116806878, STAT4 rs7574865 and CFB rs12614 (previously reported to be associated with response to PegIFNα) was related to response to PegIFNα in CHB.

CONCLUSIONS

TRIM26 inhibits HBV replication; IFN promotes TRIM26 expression. TRIM26 exerts an inhibitory effect on HBx by promoting ubiquitin-mediated degradation of HBx. Furthermore, TRIM26 rs116806878 is a potential predictive biomarker of response to PegIFNα in patients with CHB.

Surrogate Markers for Hepatitis B Virus Covalently Closed Circular DNA

Chronic infection with the hepatitis B virus (HBV) is one of the most common causes of liver disease worldwide. Chronic HBV infection is currently incurable because of the persistence of the viral template for the viral transcripts, covalently closed circular deoxyribonucleic acid (cccDNA). Detecting changes in cccDNA transcriptional activity is key to understanding fundamental virology, determining the efficacy of new therapies, and deciding the optimal clinical management of HBV patients. In this review, we summarize surrogate circulating biomarkers that have been used to infer cccDNA levels and activity in people with chronic hepatitis B. Moreover, we outline the current shortcomings of the current biomarkers and highlight the clinical importance in improving them and expanding their use.

New strategies for the treatment of chronic hepatitis B

Functional cure, as defined by seroclearance of hepatitis B surface antigen (HBsAg), is the desired treatment endpoint for chronic hepatitis B (CHB) infection, yet is rarely achieved with the currently approved therapy. Novel treatments currently in the clinical phase of development act by inhibiting viral replication/antigen reduction and/or by restoring host immune control. Although some agents are effective in reducing the viral antigen load, a greater magnitude of suppression is required to achieve functional cure. Compounds that target the covalently closed circular DNA (cccDNA) pool, hepatitis B X (HBx) protein inhibition, and mRNA destabilization are also in the preclinical phase of development. Challenges which remain include the clinical implications, immunological perturbations, and safety of these novel compounds to be used in the real-life setting.

Assessing the developing pharmacotherapeutic landscape in hepatitis B treatment: A spotlight on drugs at phase II clinical trials

INTRODUCTION

Functional cure, defined as sustained HBsAg seroclearance, is associated with favorable outcomes in chronic hepatitis B (CHB). While nucleos(t)ide analogues (NAs) are effective in suppressing HBV replication, NAs are unable to induce functional cure at high rates. A range of novel HBV antivirals, aiming to induce functional cure, are currently under development.

AREAS COVERED

This article covered novel hepatitis B virus (HBV) antivirals that have entered phase II trials. Virus-directing agents covered include entry inhibitors, transcription inhibitors, RNA silencers, core protein allosteric modulators, non-competitive polymerase inhibitors, and viral protein export inhibitors. Immunomodulators covered include innate immune stimulators, T-cell modulators, therapeutic vaccines, and monoclonal antibodies. Upcoming developmental directions would also be discussed.

EXPERT OPINION

Among novel HBV antivirals, RNA silencers, viral protein export inhibitors (with pegylated interferon) and entry inhibitors (with pegylated interferon) appear to be effective in suppressing HBsAg and may even induce functional cure. The other virus-targeting agents have variable effects on HBV DNA, HBsAg, HBeAg and HBcrAg. Immunomodulators have modest effects on HBsAg, but may have important roles in combination therapy. Upcoming trials will answer important questions on ideal dosing, long-term drug effects, and efficacy of combination regimens.

Management and Treatment of Patients with Chronic Hepatitis B: Towards Personalized Medicine

The currently available antiviral treatments (Peg-Interferon-α and Nucleos(t)ide Analogues, NA) for chronic hepatitis B (CHB) achieve a functional cure (serum HBsAg and HDV-DNA clearance) of HBV infection in a limited number of patients. Nevertheless, the continuous pharmacological suppression of viral replication by NA halts liver disease progression lowering the risk of HCC development and improving the survival. In the near future, to fully exploit the potential of old and new drugs for HBV treatment a personalized approach to the patients will be required according to an accurate definition of their virologic, immunologic and clinical profile.

Capsid Assembly Modulators as Antiviral Agents against HBV: Molecular Mechanisms and Clinical Perspectives

Despite a preventive vaccine being available, more than 250 million people suffer from chronic hepatitis B virus (HBV) infection, a major cause of liver disease and HCC. HBV infects human hepatocytes where it establishes its genome, the cccDNA with chromosomal features. Therapies controlling HBV replication exist; however, they are not sufficient to eradicate HBV cccDNA, the main cause for HBV persistence in patients. Core protein is the building block of HBV nucleocapsid. This viral protein modulates almost every step of the HBV life cycle; hence, it represents an attractive target for the development of new antiviral therapies. Capsid assembly modulators (CAM) bind to core dimers and perturb the proper nucleocapsid assembly. The potent antiviral activity of CAM has been demonstrated in cell-based and in vivo models. Moreover, several CAMs have entered clinical development. The aim of this review is to summarize the mechanism of action (MoA) and the advancements in the clinical development of CAMs and in the characterization of their mod of action.

May Previous Hepatitis B Virus Infection Be Involved in Etiology and Pathogenesis of Autoimmune Liver Diseases?

INTRODUCTION

Viral infections, especially with hepatotropic viruses, may trigger autoimmune liver diseases (AILDs) and deteriorate their course. However, association of previous hepatitis B virus (HBV) infection (presence of anti-HBc with or without anti-HBs or HBV DNA in serum) with AILDs is poorly studied so far. The aim of the study was to assess the prevalence of previous hepatitis B virus infection markers and its clinical significance in patients with autoimmune liver diseases.

METHODS

The study was based on the data obtained from 234 consecutive HBsAg-negative patients with AILDs [81 with autoimmune hepatitis (AIH), 122 with primary biliary cholangitis (PBC) and 31 with primary sclerosing cholangitis (PSC)] and 131 subjects of the control group without liver diseases. Blood samples of the enrolled patients were tested for anti-HBc and HBV DNA. Samples of liver tissue were examined by standard morphologic protocol and, in anti-HBc positive subjects, for HBV DNA. We assessed estimated risks of AILDs according to anti-HBc positivity and association of anti-HBc positivity with stage of liver fibrosis.

RESULTS

Anti-HBc was detected in 14.5% participants in the control group vs 26.1% (p = 0.016) in patients with AILDs (including 27.1% subjects with PBC (p = 0.021 vs control group), in 29% of PSC and 23.5% in AIH. HBV DNA was detected in three patients with PBC and in one with AIH. Positive anti-HBc test result was associated with higher risk of AILDs-odds ratio (OR) = 2.078 [95% confidence interval (CI) 1.179-3.665], especially in PBC: OR (95% CI) 2.186 (1.165-4.101). Odds of advanced stage of liver fibrosis (F3-F4 by METAVIR) in anti-HBc-positive subjects with PBC were also higher compared to those who had no previous HBV infection: OR (95% CI) 2.614 (1.153-5.926).

CONCLUSIONS

Significant proportions of patients with AILDs are anti-HBc positive, and some of them have OBI. Among patients with AILDs, anti-HBc-positivity is most widespread in the PBC group and in subjects with advanced stage of liver fibrosis. Our data may support the idea of an important role of previous HBV infection in the etiology and pathogenesis of AILDs (namely PBC).

Cure everyone and vaccinate the rest: The patient perspective on future hepatitis B treatment

Those living with chronic hepatitis B virus (HBV) require years, if not decades, of regular monitoring to prevent liver complications from occurring. An estimated 292 million people were living with chronic HBV globally in 2018 with approximately 2.4 million of those residing within the United States (US). This study is one of the first of its kind that aims to explore the treatment preferences for those living with chronic HBV through qualitative interviews. Participant data were collected by in-depth telephone interviews using a semi-structured discussion guide. A codebook guided the organization of data, and codes were developed by review of the literature (a priori) and through line-by-line reading of a subsample of queries. All data transcripts (N = 19) were independently double coded. Overarching themes identified from the data specific to the treatment modalities and implications of a functional HBV cure included the concern about side effects, treatment modality, frequency, duration, cost-effectiveness and overall impact on their lives. Qualitative data analysis revealed the significant impact that an HBV functional cure would have on quality of life. Benefits of a cure were described as not having a finite course of treatment, improving overall vitality, and reducing the fear and anxiety associated with lifelong infection and potential development of liver cancer. Many individuals expressed the desire for a cure for HBV, stating it would be life-changing, and a 'miracle'. As new therapies are in development, more research should examine in detail the treatment preferences of those living with HBV.

Exploring evidence-based innovative therapy for the treatment of chronic HBV infection: experimental and clinical

With the advent of various vaccines and antimicrobial agents during the 20th century, the control and containment of infectious diseases appeared to be a matter of time. However, studies unveiled the diverse natures of microbes, their lifestyle, and pathogenetic potentials. Since the ground-breaking discovery of the hepatitis B virus (HBV) by Baruch Blumberg and the subsequent development of a vaccine in the early 1980s, the main task of the scientific community has been to develop a proper management strategy for HBV-induced chronic liver diseases. In the early 1980’s, standard interferon (IFN) induced a reduction of HBV DNA levels, followed by the normalization of serum transaminases (alanine aminotransferase, ALT), in some chronic hepatitis B (CHB) patients. However, in the course of time, the limitations of standard IFN became evident, and the search for an alternative began. In the late 1980’s, nucleoside analogs entered the arena of CHB treatment as oral drugs with potent antiviral capacities. At the beginning of the 21st century, insights were developed into the scope and limitations of standard IFN, pegylated-IFN as well as nucleoside analogs for treating CHB. Considering the non-cytopathic nature of the HBV, the presence of covalently closed circular DNA (cccDNA) in the nucleus of the infected hepatocytes and HBV-induced immune-mediated liver damages, a new field of CHB management was initiated by modulating the hosts’ immune system through immune therapy. This review will discuss the nature and design of innovative immune therapy for CHB.

Discontinuation of antiviral therapy in chronic hepatitis B patients

Nucleos(t)ide analogs (NUC) are the first-line therapy for patients with chronic hepatitis B (CHB) recommended by most current guidelines. NUC therapy decreases progression of liver disease, reduces the risk of liver-related complications, and improves the quality of life of patients with CHB. Although indefinite or long-term NUC therapy is usually recommended, this strategy raises several concerns, such as side-effects, adherence, costs, and patient willingness to stop therapy. Recent data showed the feasibility, efficacy, and safety of stopping antiviral therapy in carefully selected CHB patients, leading to its incorporation in international guidelines. Patients who discontinue NUC have a higher likelihood of hepatitis B surface antigen (HBsAg) loss compared to patients who continue on therapy. Recommendations pertaining endpoints allowing safety discontinuation of NUC therapy differ among international guidelines. For hepatitis B e antigen (HBeAg)-positive patients, durable HBeAg seroconversion is considered an acceptable treatment endpoint. For HBeAg-negative patients, some guidelines propose undetectability hepatitis B virus DNA for at least 2 or 3 years, while others consider HBsAg loss as the only acceptable endpoint. CHB patients who stop therapy should remain under strict clinical and laboratorial follow-up protocols to detect and manage relapses in a timely manner. No reliable predictor of relapse has been consistently identified to date, although quantitative HBsAg has been increasingly studied as a reliable biomarker to predict safe NUC discontinuation.

Hepatitis B Virus DNA Integration, Chronic Infections and Hepatocellular Carcinoma

Hepatitis B Virus (HBV) is an Old World virus with a high mutation rate, which puts its origins in Africa alongside the origins of Homo sapiens, and is a member of the Hepadnaviridae family that is characterized by a unique viral replication cycle. It targets human hepatocytes and can lead to chronic HBV infection either after acute infection via horizontal transmission usually during infancy or childhood or via maternal-fetal transmission. HBV has been found in ~85% of HBV-related Hepatocellular Carcinomas (HCC), and it can integrate the whole or part of its genome into the host genomic DNA. The molecular mechanisms involved in the HBV DNA integration is not yet clear; thus, multiple models have been described with respect to either the relaxed-circular DNA (rcDNA) or the double-stranded linear DNA (dslDNA) of HBV. Various genes have been found to be affected by HBV DNA integration, including cell-proliferation-related genes, oncogenes and long non-coding RNA genes (lincRNAs). The present review summarizes the advances in the research of HBV DNA integration, focusing on the evolutionary and molecular side of the integration events along with the arising clinical aspects in the light of WHO's commitment to eliminate HBV and viral hepatitis by 2030.

A Focused Review on Recent Advances in the Diagnosis and Treatment of Viral Hepatitis

The global burden of viral hepatitis remains substantial despite advances in antiviral therapy and effective vaccines. There are five hepatitis viruses (hepatitis A, B, C, D, and E). Mortality related to hepatitis B virus and hepatitis C virus infections is among the top four global infectious diseases, together with human immunodeficiency virus infection, malaria, and tuberculosis. Of those deaths, approximately 47% are attributable to hepatitis B virus, 48% to hepatitis C virus and the remainder to hepatitis A virus and hepatitis E virus. Ending hepatitis epidemics as a major public health threat is feasible with the tools and approaches currently available. Effective vaccines are available for preventing viral hepatitis A, B and E infections. New oral, well-tolerated treatment regimens for chronic hepatitis C patients can achieve cure rates of over 90%. Effective treatment is also available for people with chronic hepatitis B virus infection; although for most people such treatment needs to be long-term, and recent advanced aim at a “functional cure” of hepatitis B. In this review article, we discuss the most recent advances of the diagnosis and treatment of viral hepatitis.

Innate immunity in hepatitis B and D virus infection: consequences for viral persistence, inflammation, and T cell recognition

Chronic infections with human hepatitis viruses continue to be a major health burden worldwide. Despite the availability of an effective prophylactic vaccine against the hepatitis B virus (HBV) and of antiviral agents efficiently suppressing HBV replication, more than 250 million people are currently chronically infected with this hepatotropic DNA virus, and resolution of chronic hepatitis B (CHB) is rarely achieved. Moreover, coinfection with the hepatitis D virus (HDV), a human RNA satellite virus requiring the envelope proteins of HBV for productive viral spreading, substantially aggravates the disease course of CHB. The molecular mechanisms by which these viruses interact with each other and with the intrinsic innate responses of the hepatocytes are not fully understood. While HBV appears to avoid innate immune recognition, HDV elicits a strong enhancement of innate responses. Notwithstanding, such induction does not hamper HDV replication but contributes to liver inflammation and pathogenesis. Intriguingly, HDV appears to influence the ability of T cells to recognize infected hepatocytes by boosting antigen presentation. This review focuses on current knowledge regarding how these viruses can shape and counteract the intrinsic innate responses of the hepatocytes, thus affecting the immune system and pathogenesis. Understanding the distinct strategies of persistence that HBV and HDV have evolved is central for advancing the development of curative therapies.

Chronic hepatitis B: the demise of the 'inactive carrier' phase

Chronic hepatitis B (CHB) remains a global healthcare burden. Although the recent developments in the field have led to a reduction in incidence, the morbidity and mortality including liver cirrhosis and hepatocellular carcinoma (HCC) remain a formidable challenge. Advances in understanding the immunopathogenesis of CHB have led to a recent change in clinical categorization. EASL introduced the term hepatitis B 'e' antigen (HBeAg)-negative chronic infection, to replace the historical term 'inactive carrier' disease phase, the commonest CHB phase. Although this disease phase is associated with a favorable prognosis, it is not a truly 'inactive' disease phase with no ostensible liver disease, as inferred by the previous anachronistic terminology, and the risk of spontaneous reactivation and the potential risk of disease progression and HCC development are not negligible. Likewise, the APASL also uses the term "Incidentally Detected Asymptomatic Hepatitis B surface antigen (HBsAg)-positive Subject (IDAHS)", comprising all HBsAg-positive subjects who are incidentally detected during routine tests, without any previous or present symptoms of liver disease. This entity includes HBV infection with varied stages of liver disease. Antiviral treatment is generally reserved for patients with active inflammation and/or at risk of disease progression and HCC development. HBsAg loss is considered an optimal treatment endpoint, and may also be achievable in HBeAg-negative chronic infection and IDAHS. In light of this, and the emerging novel HBV therapies, lowering the treatment threshold and a 'Treat All' approach should now be considered. In this review, we summarize the literature and guidance on HBeAg-negative chronic infection, and we make a concerted effort to present the reasons why the one-dimensional term 'inactive carrier' should be abandoned.

Long-term efficacy and safety of nucleos(t)ides analogues in patients with chronic hepatitis B

Nucleos(t)ide analogues with high barrier to resistance are regarded as the principal therapeutic option for chronic hepatitis B (CHB). Treatment with entecavir (ETV), tenofovir disoproxil (TDF) and the later released tenofovir alafenamide (TAF) is highly effective at controlling hepatitis B virus (HBV) infection and, in the vast majority of patients, is well tolerated. No significant differences in viral suppression have been described among the different regimens, although an earlier achievement in biochemical response has been suggested first under TDF and recently under TAF. High barrier to resistance NAs rarely achieve hepatitis B surface antigen sero-clearance, and therefore should be maintained life-long in most cases. This has increased concerns about treatment-related toxicity, especially in patients under TDF with additional risk factors for kidney and bone impairment. TAF has shown a better bone and kidney safety profile than TDF, although it is not yet available worldwide due to its higher cost. Emergence of adverse events should be monitored since treatment-switch to ETV/TAF seems to be effective and safe in HBV mono-infected subjects. Finally, although an effective antiviral treatment leads to a clear improvement in clinical outcome of CHB patients; the risk of developing hepatocellular carcinoma (HCC) is not completely avoided with viral suppression. Whether tenofovir-based regimens provide any additional benefit over ETV in HCC prevention remains unclear and requires further investigation.

Analysis of the Effect of Health Management of Chronic Diseases and Metabolic Disorders under the Guidance of B-Ultrasound

Chronic diseases are diseases with insidious onset, prolonged duration, and intractability and are associated with complex etiology and multiple morbidities, including hypertension, obesity, liver disease, kidney disease, cancer, cardiovascular disease, and chronic lung disease. For patients with chronic diseases, although the cause of the disease is not in the spleen and stomach, medication or further development of the disease will affect the function of the spleen and stomach disorders, leading to worsening of the disease. In this article, ultrasound is used to detect health disorders of the spleen and stomach. Patients should eat a light diet and exercise more. Elderly patients can increase abdominal massage and other health care. It should be emphasized that the prevalence of chronic diseases is not lower in people with high education or high economic income but is closely related to people's daily living habits; secondly, we should enhance physical exercise and advocate annual physical examination. Finally, we need to develop different measures according to different regions to prevent and treat chronic diseases and give timely feedback to the interventions. New preventive and curative measures are given in time to improve public health.

Characterization of Hepatitis B Precore/Core-Related Antigens

Current therapies rarely cure chronic hepatitis B virus (HBV) infection due to the persistence of the viral episome, the covalently closed circular DNA (cccDNA), in hepatocytes. The hepatitis B virus core-related antigen (HBcrAg), a mixture of the viral precore/core gene products, has emerged as one potential marker to monitor the levels and activities of intrahepatic cccDNA. In this study, a comprehensive characterization of precore/core gene products revealed that HBcrAg components included the classical hepatitis B virus core antigen (HBc) and e antigen (HBeAg) and, additionally, the precore-related antigen, PreC, retaining the N-terminal signal peptide. Both HBeAg and PreC antigens displayed heterogeneous proteolytic processing at their C termini resulting in multiple species, which varied with viral genotypes. HBeAg was the predominant form of HBcrAg in HBeAg-positive patients. Positive correlations were found between HBcrAg and PreC, between HBcrAg and HBeAg, and between PreC and HBeAg but not between HBcrAg and HBc. Serum HBeAg and PreC shared similar buoyant density and size distributions, and both displayed density and size heterogeneity. HBc, but not HBeAg or PreC antigen, was found as the main component of capsids in DNA-containing or empty virions. Neither HBeAg nor PreC protein was able to form capsids in cells or in vitro under physiological conditions. In conclusion, our study provides important new quantitative information on levels of each component of precore/core gene products as well as their biochemical and biophysical characteristics, implying that each component may have distinct functions and applications in reflecting intrahepatic viral activities.IMPORTANCE Chronic hepatitis B virus (HBV) infection afflicts approximately 257 million people, who are at high risk of progressing to chronic liver diseases, including fibrosis, cirrhosis, and hepatocellular carcinoma. Current therapies rarely achieve cure of HBV infection due to the persistence of the HBV episome, the covalently closed circular DNA (cccDNA), in the nuclei of infected hepatocytes. Peripheral markers of cccDNA levels and transcriptional activities are urgently required to guide antiviral therapy and drug development. Serum hepatitis B core-related antigen (HBcrAg) is one such emerging peripheral marker. We have characterized the components of HBcrAg in HBV-infected patients as well as in cell cultures. Our results provide important new quantitative information on levels of each HBcrAg component, as well as their biochemical and biophysical characteristics. Our findings suggest that each HBcrAg component may have distinct functions and applications in reflecting intrahepatic viral activities.

Hepatitis B Virus Cure: Targets and Future Therapies

Chronic hepatitis B virus (HBV) infection is a major global health problem. It can cause progressive liver fibrosis leading to cirrhosis with end-stage liver disease, and a markedly increased risk of hepatocellular carcinoma. In the last two decades, substantial progress has been made in the treatment of chronic hepatitis, B. However, HBV is often reactivated after stopping nucloes(t)ide analogues because antivirals alone do not directly target covalently closed circular DNA, which is the template for all viral RNAs. Therefore, although currently available antiviral therapies achieve suppression of HBV replication in the majority of patients, hepatitis B surface antigen (HBsAg) loss and seroconversion is rarely achieved despite long-term antiviral treatment (HBsAg loss of less than 10% in 5 years). Various clinical trials of agents that interrupt the HBV life cycle in hepatocytes have been conducted. Potential treatment strategies and new agents are emerging as HBV cure. A combination of current and new anti-HBV agents may increase the rate of HBsAg seroclearance; thus, optimized regimens must be validated. Here, we review the newly investigated therapeutic compounds and the results of preclinical and/or clinical trials.

Epidemiology, Natural History, and Treatment of Hepatitis Delta Virus Infection in HIV/Hepatitis B Virus Coinfection

PURPOSE OF REVIEW

Limited data exist on the prevalence, determinants, and outcomes of hepatitis delta virus (HDV) infection among HIV/hepatitis B virus (HBV)-coinfected persons. This review provides current evidence on the epidemiology, natural history, and treatment of HDV infection in patients with HIV/HBV coinfection and highlights future research needs.

RECENT FINDINGS

Cross-sectional studies in Europe, Africa, South America, and Asia show that the prevalence of HDV among HIV/HBV-coinfected patients ranges from 1.2 to 25%. No studies have evaluated the prevalence of HDV infection among HIV/HBV-coinfected patients in the USA. HDV infection increases the risk of hepatic decompensation and hepatocellular carcinoma among HIV/HBV-coinfected patients. HDV treatment remains limited to pegylated interferon-alpha, which results in sustained virologic response in fewer than 25%. Data on the epidemiology, natural history, and treatment of HDV among HIV/HBV-coinfected persons remain limited. More research is needed to address these knowledge gaps in order to better manage HDV coinfection in HIV/HBV-coinfected patients.

cccDNA Maintenance in Chronic Hepatitis B - Targeting the Matrix of Viral Replication

Chronic hepatitis B is a numerically important cause of cirrhosis and hepatocellular carcinoma, despite an effective prophylactic vaccine and well-tolerated and effective oral antivirals. Both the incapacity of the immune system to clear hepatitis B virus (HBV) infection and the unique replication strategies adopted by HBV are considered key determinants of HBV chronicity. In this regard, the formation of the HBV DNA minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, is essential not only for the production of all viral proteins but also for HBV persistence even after long-term antiviral therapy. Licensed polymerase inhibitors target the HBV reverse transcriptase activity, control the disease with long-term therapy but fail to eliminate the cccDNA. Consequently, the production of viral RNAs and proteins, including the hepatitis B surface antigen (HBsAg), is not abolished. Novel therapeutic efforts that are in the pipeline for early clinical trials explore novel targets and molecules. Such therapeutic efforts focus on achieving a functional cure, which is defined by the loss of HBsAg and undetectable HBV DNA levels in serum. Since a true cure of HBV infection requires the elimination of the cccDNA from infected cells, comprehension of the mechanisms implicated in cccDNA biogenesis, regulation and stability appears necessary to achieve HBV eradication. In this review, we will summarize the state of knowledge on cccDNA metabolism, focusing on insights suggesting potential weak points of the cccDNA that may be key for the development of therapeutic approaches and design of clinical trials aiming at lowering cccDNA loads and activity.

Recent Advances in Understanding, Diagnosing, and Treating Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection affects 292 million people worldwide and is associated with a broad range of clinical manifestations including cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Despite the availability of an effective vaccine HBV still causes nearly 900,000 deaths every year. Current treatment options keep HBV under control, but they do not offer a cure as they cannot completely clear HBV from infected hepatocytes. The recent development of reliable cell culture systems allowed for a better understanding of the host and viral mechanisms affecting HBV replication and persistence. Recent advances into the understanding of HBV biology, new potential diagnostic markers of hepatitis B infection, as well as novel antivirals targeting different steps in the HBV replication cycle are summarized in this review article.

A hook-effect-free homogeneous light-initiated chemiluminescence assay: is it reliable for screening and the quantification of the hepatitis B surface antigen?

Background

Hepatitis B virus (HBV) infection remains a threat to global public health. As a hallmark of HBV infection, hepatitis B surface antigen (HBsAg) has been used to screen for HBV infection for decades, and quantitative assays are also being clinically rejuvenated to predict the disease outcome and monitor the antiviral response. Herein, we developed and evaluated a hook-effect-free homogeneous quantitative HBsAg assay based on the light-initiated chemiluminescence immunoassay (LICA).

Methods

A hook-effect-free LICA algorithm was established by measuring the relative light units (RLUs) of two time points during the immunoreaction. The precision was assessed using low- and high-level controls. Consecutive clinical serum samples were tested using the LICA and Abbott Architect assay; samples producing inconsistent results were retested using supplementary assays including the HBsAg neutralization, HBV DNA, and Roche Elecsys HBsAg assays for further confirmation. The consistency, sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. For the quantitative results, the correlation was analyzed. The coverage of different genotypes and mutations by the LICA was evaluated. Moreover, serial on-treatment and follow-up samples from chronic hepatitis B patients were also measured using the two assays.

Results

The LICA had better within-run and within-laboratory precisions than the Architect assay. In total, 5,176 clinical samples were tested. The two assays showed a consistency of 99.63%. The LICA showed greater specificity (99.95% vs. 99.77%) and PPV (99.75% vs. 98.77%) than the Architect assay, whereas the Architect assay showed greater sensitivity (100.00% vs. 99.01%) and NPV (100.00% vs. 99.82%). The two assays displayed an excellent correlation independent of genotypes and mutations. The LICA hook-free algorithm recognized 100% of the underestimated results. Furthermore, similar HBsAg dynamics were demonstrated using the LICA and Architect HBsAg assay.

Conclusions

The hook-free LICA provides a reliable tool for screening for HBV infection and quantifying HBsAg.

Current practice and contrasting views on discontinuation of nucleos(t)ide analog therapy in chronic hepatitis B

Introduction: Long-term, even indefinite treatment with nucleos(t)ide analogs (NAs) is the current first-line therapy for patients with chronic hepatitis B (CHB), regardless of its histological stage. Guidelines and recommendations on duration and endpoints of NA therapy in CHB are not identical and change over time.Areas covered: The authors review NA discontinuation approaches and views with an emphasis on HBeAg-negative patients based on published studies relevant to the topic, stressing on whether or not the optimal endpoint of HBsAg loss is practically achievable.Expert opinion: Discontinuation of NA therapy in HBeAg-negative noncirrhotic patients has to be considered after long-term effective treatment with controlled liver disease activity, undetectable viremia, and significant decline in serum HBsAg titers. Close post-treatment monitoring is required for early intervention in cases of severe clinical relapse. Immediate retreatment hampers the favorable outcome of HBsAg clearance (functional cure) and should be avoided in transient ALT flares. Predictors of such relapses are still under investigation and include viral and patient factors. For HBeAg-positive noncirrhotic patients, there is wide acceptance of the endpoint of HBeAg seroconversion, after a long consolidation period.

Chronic Viral Hepatitis: Current Management and Future Directions

The past decade has seen transformation in the strategies for identifying and managing viral hepatitis, most dramatically the transformation of hepatitis C virus from a mostly chronic affliction to a curable disease that is accessible to wide populations through direct-acting antiviral therapies. More recently, shifting of hepatitis C virus burden to younger patients driven by intravenous drug use has shaped screening recommendations. Future work focusing on effective screening, linkage to care, treatment initiation, and post-cure management will allow countries to work toward meeting goals of eliminating viral hepatitis as a major public health threat. Concurrently, hepatitis B virus has also seen advances in management using oral nucleos(t)ide therapies with high-resistance barriers. However, virologic cure remains elusive in the setting of viral genetic persistence within the hepatocyte nucleus, even with suppressive antiviral therapy. Future directions include a refined definition of "cure," new biomarkers, and development of therapies targeting multiple pathways in the viral pathogenic and replication pathway. Progress is additionally being made on the management of hepatitis D infection. This review summarizes the recent evolution in disease characteristics, associated affected population, and changes in our understanding of management for these infections. We also discuss future directions in the management of viral hepatitis, including discussion on issues related to management before and after antiviral therapy. Conclusion: We summarize recent advances in the identification and management of viral hepatitis, which hold the potential to markedly reduce disease burden and therefore associated liver-related complications. However further work is needed to adequately identify and manage these diseases.

Progress towards elimination goals for viral hepatitis

The global burden of viral hepatitis is substantial; in terms of mortality, hepatitis B virus and hepatitis C virus infections are on a par with HIV, malaria and tuberculosis, among the top four global infectious diseases. In 2016, the 194 Member States of the World Health Organization committed to eliminating viral hepatitis as a public health threat by 2030, with a particular focus on hepatitis B virus and hepatitis C virus infection. With only 10 years to go until the 2030 deadline is reached, and although much progress has been made towards elimination, there are still some important gaps in terms of policy and progress. In this Viewpoint, we asked a selection of scientists and clinicians working in the viral hepatitis field for their opinions on whether elimination of viral hepatitis by 2030 is feasible, what the key areas of progress are and what the focus for the next 10 years and beyond should be for viral hepatitis elimination.