Efficacy and Safety of Bepirovirsen in Chronic Hepatitis B Infection

Predictors of HBsAg seroclearance in patients with chronic HBV infection treated with pegylated interferon-α: a systematic review and meta-analysis

BACKGROUND AND AIMS

The identification of reliable predictors for hepatitis B surface antigen (HBsAg) seroclearance remains controversial. We aimed to summarize potential predictors for HBsAg seroclearance by pegylated interferon-α (PegIFNα) in patients with chronic HBV infection.

METHODS

A systematic search of the Cochrane Library, Embase, PubMed, and Web of Science databases was conducted from their inception to 28 September 2022. Meta-analyses were performed following the PRISMA statement. Predictors of HBsAg seroclearance were evaluated based on baseline characteristics and on-treatment indicators.

RESULTS

This meta-analysis encompasses 27 studies, including a total of 7913 patients. The findings reveal several factors independently associated with HBsAg seroclearance induced by PegIFNα-based regimens. These factors include age (OR = 0.961), gender (male vs. female, OR = 0.537), genotype (A vs. B/D; OR = 7.472, OR = 10.738), treatment strategy (combination vs. monotherapy, OR = 2.126), baseline HBV DNA (OR = 0.414), baseline HBsAg (OR = 0.373), HBsAg levels at week 12 and 24 (OR = 0.384, OR = 0.294), HBsAg decline from baseline to week 12 and 24 (OR = 6.689, OR = 6.513), HBsAg decline from baseline ≥ 1 log10 IU/ml and ≥ 0.5 log10 IU/ml at week 12 (OR = 18.277; OR = 4.530), and ALT elevation at week 12 (OR = 3.622). Notably, subgroup analysis suggests no statistical association between HBsAg levels at week 12 and HBsAg seroclearance for treatment duration exceeding 48 weeks. The remaining results were consistent with the overall analysis.

CONCLUSIONS

This is the first meta-analysis to identify predictors of HBsAg seroclearance with PegIFNα-based regimens, including baseline and on-treatment factors, which is valuable in developing a better integrated predictive model for HBsAg seroclearance to guide individualized treatment and achieve the highest cost-effectiveness of PegIFNα.

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.

The lack of HBsAg secretion does neither facilitate induction of antiviral T cell responses nor Hepatitis B Virus clearance in mice

Immune tolerance to the hepatitis B virus (HBV) is crucial for developing chronic hepatitis B, and the HBV surface antigen (HBsAg) produced and secreted in high amounts is regarded as a key contributor. HBsAg is expressed in HBV-infected hepatocytes and those carrying an HBV integration. Whether either HBsAg secretion or the high antigen amount expressed in the liver determines its immunomodulatory properties, however, remains unclear. We, therefore, developed a novel HBV animal model that allowed us to study the role of secreted HBsAg. We introduced a previously described HBs mutation, C65S, abolishing HBsAg secretion into a replication-competent 1.3-overlength HBV genome and used adeno-associated virus vectors to deliver it to the mouse liver. The AAV-HBV established a carrier state of wildtype and C65S mutant HBV, respectively. We investigated antiviral B- and T-cell immunity in the HBV-carrier mice after therapeutic vaccination. Moreover, we compared the effect of a lacking HBsAg secretion with that of an antiviral siRNA. While missing HBsAg secretion allowed for higher levels of detectable anti-HBs antibodies after therapeutic vaccination, it did neither affect antiviral T-cell responses nor intrahepatic HBV gene expression, irrespective of the starting level. A treatment with HBV siRNA restricting viral antigen expression within hepatocytes, however, improved the antiviral efficacy of therapeutic vaccination, irrespective of the ability of HBV to secrete HBsAg. Our data indicate that clearing HBsAg from blood cannot significantly impact HBV persistence or T-cell immunity. This indicates that a restriction of hepatic viral antigen expression will be required to break HBV immunotolerance.

A mutual regulatory loop between transcription factor Yin Yang 1 and hepatitis B virus replication influences chronic hepatitis B

Hepatitis B virus (HBV) infections pose a major threat to human health. HBV can upregulate the expression of the transcription factor Yin Yang 1 (YY1) in in vitro cytological experiments, suggesting an association between YY1 and HBV infection. However, data on YY1 expression in chronic hepatitis B (CHB) patients are lacking. In this study, we aimed to assess the correlation between YY1 expression and HBV infection. We detected serum YY1 levels in 420 patients with chronic HBV infection, 30 patients with chronic hepatitis C virus infection, and 32 healthy controls using an enzyme-linked immunosorbent assay. The correlation between YY1 levels and clinical parameters was analyzed. Meanwhile, the changes of YY1 before and after interferon or entecavir treatment were analyzed. YY1 levels in the liver tissues were detected using immunofluorescence staining. The expression of YY1 in HBV-expressing cells was detected through western blotting. Meanwhile, we explored the effects of YY1 on HBV replication and gene expression. We found that YY1 was highly expressed in the serum and liver tissues of CHB patients. Serum YY1 levels positively correlated with HBV DNA and hepatitis B surface antigen (HBsAg). Additionally, HBV DNA levels increased but HBsAg levels decreased after HBV-expressing cells overexpress YY1. In conclusion, our study demonstrates that YY1 plays an important role in HBV replication and gene expression, providing a potential target for the treatment of CHB.

Intracellular Host Restriction of Hepatitis B Virus Replication

The hepatitis B virus (HBV) infects hepatocytes and hijacks host cellular mechanisms for its replication. Host proteins can be frontline effectors of the cell's defense and restrict viral replication by impeding multiple steps during its intracellular lifecycle. This review summarizes many of the well-described restriction factors, their mechanisms of restriction, and counteractive measures of HBV, with a special focus on viral transcription. We discuss some of the limitations and knowledge gaps about the restriction factors, highlighting how these factors may be harnessed to facilitate therapeutic strategies against HBV.

Targeted delivery strategies: The interactions and applications of nanoparticles in liver diseases

In recent years, nanoparticles have been broadly utilized in various drugs delivery formulations. Nanodelivery systems have shown promise in solving problems associated with the distribution of hydrophobic drugs and have promoted the accumulation of nanomedicines in the circulation or in organs. However, the injection dose of nanoparticles (NPs) is much greater than that needed by diseased tissues or organs. In other words, most of the NPs are localized off-target and do not reach the desired tissue or organs. With the rapid development of biodegradable and biosafety nanomaterials, the nanovectors represent assurance of safety. However, the off-target effects also induce concerns about the application of NPs, especially in the delivery of gene editing tools. Therefore, a complete understanding of the biological responses to NPs in the body will clearly guide the design of targeted delivery of NPs. The different properties of various nanodelivery systems may induce diverse interactions between carriers and organs. In this review, we describe the relationship between the liver, the most influenced organ of systemic administration of NPs, and targeted delivery nanoplatforms. Various transport vehicles have adopted multiple delivery strategies for the targeted delivery to the cells in the homeostasis liver and in diseased liver. Additionally, nanodelivery systems provide a novel strategy for treating incurable diseases. The appearance of a targeted delivery has profoundly improved the application of NPs to liver diseases.

Hepatitis B: Model Systems and Therapeutic Approaches

Hepatitis B virus (HBV) infection is a major global health issue and ranks among the top causes of liver cirrhosis and hepatocellular carcinoma. Although current antiviral medications, including nucleot(s)ide analogs and interferons, could inhibit the replication of HBV and alleviate the disease, HBV cannot be fully eradicated. The development of cellular and animal models for HBV infection plays an important role in exploring effective anti-HBV medicine. During the past decades, advancements in several cell culture systems, such as HepG2.2.15, HepAD38, HepaRG, hepatocyte-like cells, and primary human hepatocytes, have propelled the research in inhibiting HBV replication and expression and thus enriched our comprehension of the viral life cycle and enhancing antiviral drug evaluation efficacy. Mouse models, in particular, have emerged as the most extensively studied HBV animal models. Additionally, the present landscape of HBV therapeutics research now encompasses a comprehensive assessment of the virus's life cycle, targeting numerous facets and employing a variety of immunomodulatory approaches, including entry inhibitors, strategies aimed at cccDNA, RNA interference technologies, toll-like receptor agonists, and, notably, traditional Chinese medicine (TCM). This review describes the attributes and limitations of existing HBV model systems and surveys novel advancements in HBV treatment modalities, which will offer deeper insights toward discovering potentially efficacious pharmaceutical interventions.

Advances in the Pharmacological Management of Chronic Hepatitis B

BACKGROUND

Hepatitis B, a vaccine-preventable liver infection, remains a global public health problem. Dedicated groups of experts and funding are focusing on achieving a functional cure to eradicate this disease by 2030.

AREAS OF UNCERTAINTY

With more than 40 molecules available or under investigation as new treatments for hepatitis B virus (HBV) infection, none of them is curative so far. Available treatments are effective in suppressing HBV replication and in decreasing the risk of developing cirrhosis, liver failure, hepatocellular carcinoma, and death, but do not eliminate the virus, and the risk of hepatocellular carcinoma remains. Nucleoside/nucleotide analogs are recommended as first-line therapy for patients with chronic hepatitis B infection to inhibit viral replication and lower the HBV DNA values, but long-term therapy is usually needed to maintain suppression. Cessation of the therapy in accordance with clinical guidelines can result in virological and clinical relapse.

DATA SOURCES

PubMed, Web of Science, clinicaltrials.gov , and gray literature sources were searched for articles discussing HBV management and new therapies.

RESULTS

With current nucleoside/nucleotide analog therapies, fewer than 5% of patients lose hepatitis B surface antigen after 12 months, which underscores the need for new drugs that can achieve a functional cure. New therapies are being developed, including small interfering RNAs. Bepirovirsen, a modified antisense oligonucleotide, shows promising results and a good safety profile, but requires further exploration in larger number of patients to determine whether a functional cure is possible.

CONCLUSIONS

Eradication of HBV infection with currently available therapies is not yet possible. Experts are developing innovative treatments, such as bepirovirsen, to achieve functional cure for this disease and to reduce morbidity and mortality associated with hepatic cirrhosis and hepatocellular carcinoma.

Optimal Treatment Based on Interferon No Longer Makes Clinical Cure of Chronic Hepatitis B Far Away: An Evidence-Based Review on Emerging Clinical Data

Chronic hepatitis B (CHB) remains a major global public health problem. The functional cure is the ideal therapeutic target recommended by the latest guidelines, and pursuing a functional cure has become the key treatment end point of current therapy and for upcoming clinical trials. In this review, based on the latest published clinical research evidence, we analyzed the concept and connotation of clinical cures and elaborated on the benefits of clinical cures in detail. Secondly, we have summarized various potential treatment methods for achieving clinical cures, especially elaborating on the latest research progress of interferon-based optimized treatment strategies in achieving clinical cures. We also analyzed which populations can achieve clinical cures and conducted a detailed analysis of relevant virological and serological markers in screening clinical cure advantage populations and predicting clinical cure achievement. In addition, we also introduced the difficulties that may be encountered in the current pursuit of achieving a clinical cure.

Chronic Hepatitis B Finite Treatment: Similar and Different Concerns With New Drug Classes

Chronic hepatitis B, a major cause of liver disease and cancer, affects >250 million people worldwide. Currently there is no cure, only suppressive therapies. Efforts to develop finite curative hepatitis B virus (HBV) therapies are underway, consisting of combinations of multiple novel agents with or without nucleos(t)ide reverse-transcriptase inhibitors. The HBV Forum convened a webinar in July 2021, along with subsequent working group discussions to address how and when to stop finite therapy for demonstration of sustained off-treatment efficacy and safety responses. Participants included leading experts in academia, clinical practice, pharmaceutical companies, patient representatives, and regulatory agencies. This Viewpoints article outlines areas of consensus within our multistakeholder group for stopping finite therapies in chronic hepatitis B investigational studies, including trial design, patient selection, outcomes, biomarkers, predefined stopping criteria, predefined retreatment criteria, duration of investigational therapies, and follow-up after stopping therapy. Future research of unmet needs are discussed.

Viral hepatitis-induced acute liver failure

Viral hepatitis-induced acute liver failure (ALF) is a preventable cause for liver-related mortality worldwide. Viruses are the most common cause for ALF in developing nations in contrast to the west, where acetaminophen is largely responsible. Viruses may be hepatotropic or affect the liver secondary to a systemic infection. In tropical countries, infections such as leptospirosis, scrub typhus and malaria can mimic the symptoms of ALF. Differentiating these ALF mimics is crucial because they require etiology-specific therapy. Treatment of viral hepatitis-induced ALF is two-pronged and directed towards providing supportive care to prevent organ failures and antiviral drugs for some viruses. Liver transplantation (LT) is an effective modality for patients deteriorating despite adequate supportive care. Early referral and correct identification of patients who require a transplant are important. Liver support devices and plasma exchange have evolved into "bridging modalities" for LT. Preventive strategies such as hand hygiene, use of clean and potable water and inclusion of vaccines against viral hepatitis in the national program are simple yet very effective methods focusing on the preventive aspect of this disease.

Under-representation of the WHO African region in clinical trials of interventions against hepatitis B virus infection

The WHO African region bears a disproportionate burden of morbidity and mortality related to chronic hepatitis B virus (HBV) infection and accounts for an estimated 70% of new HBV infections worldwide. We investigated the extent to which HBV clinical trials represented populations in this region by searching the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov for interventional clinical trials published in English between database inception and May 29, 2023, using the search term "Hepatitis B". We identified 1804 unique clinical trials, of which 18 (1·0%) recorded involvement of the WHO African region. There is no evidence that the number of HBV clinical trials in this region has improved over time. The diversity of new interventions and industry sponsorship in the WHO African region were low, with trials of HBV comparing poorly with those of other endemic infectious diseases (eg, malaria, HIV, and SARS-CoV-2). HBV research and clinical trial investigations have neglected the WHO African region, leading to profound health inequities. HBV clinical trials are urgently needed to evaluate the efficacy of newly discovered therapeutics and to ensure that interventions can be equitably distributed and deployed as they become available.

Addition of PEG-interferon to long-term nucleos(t)ide analogue therapy enhances HBsAg decline and clearance in HBeAg-negative chronic hepatitis B: Multicentre Randomized Trial (PAS Study)

We studied whether 48 weeks of PEG-IFN alfa-2a add-on increases HBsAg-decline and clearance in HBeAg-negative patients on long-term nucleo(s)tide analogue (NA) therapy. In this investigator-initiated, randomized, controlled trial conducted in Europe and Canada, HBeAg-negative patients treated with NA > 12 months, with HBVDNA < 200 IU/mL, were enrolled. Patients were randomized 2:1 to 48 weeks of PEG-IFN alfa-2a add-on (180 μg per week) or continued NA-monotherapy with subsequent follow-up to Week 72. Endpoints were HBsAg decline (≥1 log10 IU/mL) and HBsAg clearance at Week 48. Of the 86 patients in the modified-intention-to-treat analysis, 58 patients received PEG-IFN add-on, and 28 continued NA monotherapy. At Week 48, 16(28%) patients achieved HBsAg decline ≥1 log10 in the add-on arm versus none on NA-monotherapy (p < .001), and HBsAg clearance was observed in 6 (10%) PEG-IFN add-on patients versus 0% NA-monotherapy (p = .01). HBVRNA was only detected in 2% after PEG-IFN treatment versus 19% in NA-monotherapy (p = .002) at Week 48. PEG-IFN add-on therapy was well tolerated in majority of patients. Low baseline HBsAg levels (<10 IU/mL) identified patients most likely to achieve HBsAg loss with PEG-IFN add-on, whereas an HBsAg level > 200 IU/mL at on-treatment Week 12 was highly predictive of non-response (NPV = 100%). Addition of PEG-IFN to long-term NA enhanced HBsAg decline and increased the chance of HBsAg clearance in HBeAg-negative patients on long-term NA. On-treatment HBsAg levels >200 IU/mL identify patients unlikely to benefit from PEG-IFN add-on and could be used as a potential stopping-rule for PEG-IFN therapy. Our findings support further exploration of immune modulation add-on to antiviral therapy, preferably using response-guided strategies, to increase functional cure rates in patients with CHB.

The current perspective and opportunities of small nucleic acid-based therapeutics

Compared to traditional small molecule and antibody drugs, RNA-based drugs offer a simple design, short research and development cycles, high specificity, broad treatment fields, and long-term efficacy. As a result, RNA-based drugs are extensively used to treat genetic diseases, tumors, viral infections, and other illnesses, suggesting that they have the potential to become the third-largest drug class after small molecule and antibody drugs. Currently, more than 10 small nucleic acid drugs have gained regulatory approval. The commercialization successes of small nucleic acid drugs will stimulate the development of RNA-based drugs. Small nucleic acid drugs primarily target liver diseases, metabolic diseases, genetic diseases, and tumors, and there is also significant potential for expanding indications in the future. This review provides a brief overview of the advantages and development of small nucleic acid-based therapeutics and shows a focus on platform technologies such as chemical modifications and delivery systems that have enabled the clinical translation of small nucleic acid-based therapeutics. Additionally, we summarize the latest clinical progress in small nucleic acid-based therapeutics for the treatment of various diseases, including rare diseases, liver diseases, metabolic diseases, and tumors. Finally, we highlight the future prospects for this promising treatment approach.

Prospects for Controlling Hepatitis B Globally

Infection with the hepatitis B virus (HBV) is highly prevalent globally. Over 250 million people suffer from chronic hepatitis B, and more than 800,000 patients die each year due to hepatitis B complications, including liver cancer. Although protective HBV vaccines are recommended for all newborns, global coverage is suboptimal. In adults, sexual transmission is by far the most frequent route of contagion. The WHO estimates that 1.5 million new HBV infections occur annually. Oral nucleos(t)ide analogues entecavir and tenofovir are the most frequent antivirals prescribed as HBV therapy. Almost all patients adherent to the medication achieve undetectable plasma viremia beyond 6 months of monotherapy. However, less than 5% achieve anti-HBs seroconversion, and viral rebound occurs following drug discontinuation. Therefore, nucleos(t)ide analogues need to be lifelong. New long-acting formulations of tenofovir and entecavir are being developed that will maximize treatment benefit and overcome adherence barriers. Furthermore, new antiviral agents are in development, including entry inhibitors, capside assembly modulators, and RNA interference molecules. The use of combination therapy pursues a functional HBV cure, meaning it is negative for both circulating HBV-DNA and HBsAg. Even when this goal is achieved, the cccDNA reservoir within infected hepatocytes remains a signal of past infection, and HBV can reactivate under immune suppression. Therefore, new gene therapies, including gene editing, are eagerly being pursued to silence or definitively disrupt HBV genomes within infected hepatocytes and, in this way, ultimately cure hepatitis B. At this time, three actions can be taken to push HBV eradication globally: (1) expand universal newborn HBV vaccination; (2) perform once-in-life testing of all adults to identify susceptible HBV persons that could be vaccinated (or re-vaccinated) and unveil asymptomatic carriers that could benefit from treatment; and (3) provide earlier antiviral therapy to chronic HBV carriers, as being aviremic reduces the risk of both clinical progression and transmission.

Longterm Outcome of Therapeutic Vaccination with a Third Generation Pre-S/S HBV Vaccine (PreHevbrioR) of Chronically HBV Infected Patients

Several antiviral treatment regimens for chronic hepatitis B (CHB) virus infection have been shown to be effective in suppressing viral load and reducing the risk of hepatocellular injury and its complications. It has been hypothesized that high levels of circulating HBV surface antigen(s) may lead to immune tolerance against HBV and contribute to chronic carriership. Conversely, low-level HBsAg may create a window for the reconstitution of an HBV-specific immune response through vaccination and control of infection. Previous studies in non-responders to yeast-derived HBV vaccines, using a third-generation pre-S/S vaccine, have led to up to 95% anti-HBs seroconversion. This report evaluates the long-term outcome after experimental vaccination with a pre-S/S HBV vaccine intended as a therapeutic intervention in chronic HBV carriers. Four low-level HBsAg carriers (<500 IU/mL) were vaccinated three to seven times with 20 μg PreHevbrioR. Three out of four carriers eliminated HBsAg completely and seroconverted to anti-HBs. One patient seroconverted to anti-HBs but remained with a borderline HBsAg titer (10 IU/mL). Serum anti-HBs levels following repeated vaccination varied between 27 and >1000 IU/L, respectively. Long-term observation (>6 years) showed that after discontinuing NUC treatment for at least two years, HBsAg and HBV DNA remained negative with anti-HBs positive titers ranging between 80 and >1000 IU/L. Based on our preliminary observations, there is a rationale to further evaluate the role of this vaccine as a therapeutic agent.

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.

Elimination of the hepatitis B virus: A goal, a challenge

The hepatitis B elimination is a goal proposed by the WHO to be achieved by 2030 through the adoption of synergistic measures for the prevention and chronic HBV infection treatment. Complete cure is characterized by the HBV elimination from the body and is the goal of the chronic hepatitis B treatment, which once achieved, will enable the hepatitis B elimination. This, today, has been a scientific challenge. The difficulty in achieving a complete cure is due to the indefinite maintenance of a covalently closed episomal circular DNA (cccDNA) reservoir and the maintenance and persistence of an insufficient and dysfunctional immune response in chronically infected patients. Among the measures adopted to eliminate hepatitis B, two have the potential to directly interfere with the virus cycle, but with limited effect on HBV control. These are conventional vaccines-blocking transmission and antiviral therapy-inhibiting replication. Vaccines, despite their effectiveness in protecting against horizontal transmission and preventing mother-to-child vertical transmission, have no effect on chronic infection or potential to eliminate the virus. Treatment with antivirals suppresses viral replication, but has no curative effect, as it has no action against cccDNA. Therapeutic vaccines comprise an additional approach in the chronic infection treatment, however, they have only a modest effect on the immune system, enhancing it temporarily. This manuscript aims to address (1) the cccDNA persistence in the hepatocyte nucleus and the immune response dysfunction in chronically infected individuals as two primary factors that have hampered the treatment and HBV elimination from the human body; (2) the limitations of antiviral therapy and therapeutic vaccines, as strategies to control hepatitis B; and (3) the possibly promising therapeutic approaches for the complete cure and elimination of hepatitis B.

Retreatment with HBV siRNA Results in Additional Reduction in HBV Antigenemia and Immune Stimulation in the AAV-HBV Mouse Model

BACKGROUND AND AIMS

Treatment with siRNAs that target HBV has demonstrated robust declines in HBV antigens. This effect is also observed in the AAV-HBV mouse model, which was used to investigate if two cycles of GalNAc-HBV-siRNA treatment could induce deeper declines in HBsAg levels or prevent rebound, and to provide insights into the liver immune microenvironment.

METHODS

C57Bl/6 mice were transduced with one of two different titers of AAV-HBV for 28 days, resulting in stable levels of HBsAg of about 103 or 105 IU/mL. Mice were treated for 12 weeks (four doses q3wk) per cycle with 3 mg/kg of siRNA-targeting HBV or an irrelevant sequence either once (single treatment) or twice (retreatment) with an 8-week treatment pause in between. Blood was collected to evaluate viral parameters. Nine weeks after the last treatment, liver samples were collected to perform phenotyping, bulk RNA-sequencing, and immunohistochemistry.

RESULTS

Independent of HBsAg baseline levels, treatment with HBV-siRNA induced a rapid decline in HBsAg levels, which then plateaued before gradually rebounding 12 weeks after treatment stopped. A second cycle of HBV-siRNA treatment induced a further decline in HBsAg levels in serum and the liver, reaching undetectable levels and preventing rebound when baseline levels were 103 IU/mL. This was accompanied with a significant increase in inflammatory macrophages in the liver and significant upregulation of regulatory T-cells and T-cells expressing immune checkpoint receptors.

CONCLUSIONS

Retreatment induced an additional decline in HBsAg levels, reaching undetectable levels when baseline HBsAg levels were 3log10 or less. This correlated with T-cell activation and upregulation of Trem2.

Preclinical Antiviral and Safety Profiling of the HBV RNA Destabilizer AB-161

HBV RNA destabilizers are a class of small-molecule compounds that target the noncanonical poly(A) RNA polymerases PAPD5 and PAPD7, resulting in HBV RNA degradation and the suppression of viral proteins including the hepatitis B surface antigen (HBsAg). AB-161 is a next-generation HBV RNA destabilizer with potent antiviral activity, inhibiting HBsAg expressed from cccDNA and integrated HBV DNA in HBV cell-based models. AB-161 exhibits broad HBV genotype coverage, maintains activity against variants resistant to nucleoside analogs, and shows additive effects on HBV replication when combined with other classes of HBV inhibitors. In AAV-HBV-transduced mice, the dose-dependent reduction of HBsAg correlated with concentrations of AB-161 in the liver reaching above its effective concentration mediating 90% inhibition (EC90), compared to concentrations in plasma which were substantially below its EC90, indicating that high liver exposure drives antiviral activities. In preclinical 13-week safety studies, minor non-adverse delays in sensory nerve conductance velocity were noted in the high-dose groups in rats and dogs. However, all nerve conduction metrics remained within physiologically normal ranges, with no neurobehavioral or histopathological findings. Despite the improved neurotoxicity profile, microscopic findings associated with male reproductive toxicity were detected in dogs, which subsequently led to the discontinuation of AB-161's clinical development.

Classifying hepatitis B therapies with insights from covalently closed circular DNA dynamics

The achievement of a functional cure for chronic hepatitis B (CHB) remains limited to a minority of patients treated with currently approved drugs. The primary objective in developing new anti-HBV drugs is to enhance the functional cure rates for CHB. A critical prerequisite for the functional cure of CHB is a substantial reduction, or even eradication of covalently closed circular DNA (cccDNA). Within this context, the changes in cccDNA levels during treatment become as a pivotal concern. We have previously analyzed the factors influencing cccDNA dynamics and introduced a preliminary classification of hepatitis B treatment strategies based on these dynamics. In this review, we employ a systems thinking perspective to elucidate the fundamental aspects of the HBV replication cycle and to rationalize the classification of treatment strategies according to their impact on the dynamic equilibrium of cccDNA. Building upon this foundation, we categorize current anti-HBV strategies into two distinct groups and advocate for their combined use to significantly reduce cccDNA levels within a well-defined timeframe.

Prevention in Hepatology

The prevention of liver disease has improved significantly in the last few decades, to the point that it can now be considered a true success story. The wide variety of interventions, including comprehensive vaccination strategies, novel medications, lifestyle changes, and even preventive surgeries, have reduced the morbidity and mortality of chronic liver diseases. However, the prevalence of chronic liver diseases is increasing worldwide. Currently, fatty liver disease alone is estimated to be present in as much as 30% of the adult population. Furthermore, there is a trend towards increasing incidences of chronic hepatitis B, and a global lack of success in efforts to eliminate chronic hepatitis C. Thus, improving and efficiently rolling out existing and successful prevention strategies for chronic liver diseases will play an essential role in healthcare throughout the upcoming decades. In this review, we summarize the current options and concepts for preventing chronic liver diseases, highlight their limitations, and provide an outlook on probable future developments to improve awareness, integrated care, and the analysis of big data.

Hepatitis B Virus Reactivation with Immunosuppression: A Hidden Threat?

Hepatitis B virus (HBV) reactivation in the setting of immunosuppressive therapy is an increasingly recognized and preventable cause of elevated liver enzymes and clinical hepatitis in treated patients. However, not all immunosuppressive therapies confer the same risk. The purpose of this article was to review the literature on risks of HBV reactivation associated with immunosuppressive agents and propose a management algorithm. We searched Google Scholar, PubMed, and MEDLINE for studies related to hepatitis B reactivation and various immunosuppressive agents. The risk of HBV reactivation was found to differ by agent and depending on whether a patient had chronic HBV (HBsAg+) or past HBV (HBsAg-, anti-HBc+). The highest risk of reactivation (>10%) was associated with anti-CD20 agents and hematopoietic stem cell transplants. Multiple societies recommend HBV-specific anti-viral prophylaxis for patients with positive HBsAg prior to the initiation of immunosuppressive therapy, while the guidance for HBsAg- patients is more variable. Clinicians should check HBV status prior to beginning an immune-suppressive therapy. Patients with positive HBsAg should be initiated on antiviral prophylaxis in the majority of cases, whereas HBsAg- individuals should be evaluated on a case-by-case basis. Further research is required to determine the optimum duration of therapy.

Novel Approaches to Inhibition of HBsAg Expression from cccDNA and Chromosomal Integrants: A Review

Hepatitis B virus (HBV) is a widely prevalent liver infection that can cause acute or chronic hepatitis. Although current treatment modalities are highly effective in the suppression of viral levels, they cannot eliminate the virus or achieve definitive cure. This is a consequence of the complex nature of HBV-host interactions. Major challenges to achieving sustained viral suppression include the presence of a high viral burden from the HBV DNA and hepatitis B surface antigen (HBsAg), the presence of reservoirs for HBV replication and antigen production, and the HBV-impaired innate and adaptive immune response of the host. Those therapeutic methods include cell entry inhibitors, HBsAg inhibitors, gene editing approaches, immune-targeting therapies and direct inhibitors of covalently closed circular DNA (cccDNA). Novel approaches that target these key mechanisms are now being studied in preclinical and clinical phases. In this review article, we provide a comprehensive review on mechanisms by which HBV escapes elimination from current treatments, and highlight new agents to achieve a definitive HBV cure.

Gene-Editing and RNA Interference in Treating Hepatitis B: A Review

The hepatitis B virus (HBV) continues to cause substantial health and economic burdens, and its target of elimination may not be reached in 2030 without further efforts in diagnostics, non-pharmaceutical prevention measures, vaccination, and treatment. Current therapeutic options in chronic HBV, based on interferons and/or nucleos(t)ide analogs, suppress the virus replication but do not eliminate the pathogen and suffer from several constraints. This paper reviews the progress on biotechnological approaches in functional and definitive HBV treatments, including gene-editing tools, i.e., zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9, as well as therapeutics based on RNA interference. The advantages and challenges of these approaches are also discussed. Although the safety and efficacy of gene-editing tools in HBV therapies are yet to be demonstrated, they show promise for the revitalization of a much-needed advance in the field and offer viral eradication. Particular hopes are related to CRISPR/Cas9; however, therapeutics employing this system are yet to enter the clinical testing phases. In contrast, a number of candidates based on RNA interference, intending to confer a functional cure, have already been introduced to human studies. However, larger and longer trials are required to assess their efficacy and safety. Considering that prevention is always superior to treatment, it is essential to pursue global efforts in HBV vaccination.

Symptoms of Liver Disease During Tenofovir Therapy With or Without Peginterferon: Results from the Hepatitis B Research Network Immune Active Trial

AIMS

Evaluate patient-reported liver symptoms during treatment for chronic hepatitis B viral (HBV) infection and associations between changes in symptoms and levels of alanine aminotransferase (ALT) and viral markers.

METHODS

Data from 200 participants in the Hepatitis B Research Network Immune Active Trial who completed symptom assessments were analyzed. Patients were treated with tenofovir, with or without peginterferon (TDF + PegIFN vs. TDF alone) for 192 weeks. Participants completed a Symptom Checklist at baseline and every 4-12 weeks. A total symptom score was created, ranging from 0 (none) to 40 (severe). The SF-36 was completed every 48 weeks. Associations of symptom scores with ALT and viral markers were evaluated at baseline and end of treatment.

RESULTS

Participants were 65% male, 83% Asian, with a mean age of 42. Baseline symptoms were mild (median = 2, range 0-25) and associated with baseline ALT, HBV DNA levels and HBeAg + status. Patients on TDF alone experienced a more rapid and greater improvement in symptoms, but by week 192, symptom improvement was similar in both groups (54% vs 36%). Symptom improvements correlated with ALT and HBV DNA, most markedly among those with symptoms at baseline. Most patients (4 out of 6) who achieved HBsAg loss experienced symptom improvements. Overall, SF-36 scores did not change with treatment.

CONCLUSIONS

Reduction in ALT and HBV DNA levels with therapy are associated with significant improvement in liver symptoms such as fatigue and pain over the liver, especially among those with higher ALT, HBV DNA, symptoms and HBeAg + status prior to treatment.

Hepatitis-B virus: replication cycle, targets, and antiviral approaches

An estimated 257 million people are chronic carriers of hepatitis-B virus (HBV) infection, which resulted in around 1 million deaths, mainly due to hepatocellular carcinoma (HCC). Long-term nucleotide analog treatment of HBV infection is associated with favorable prognosis, no disease progression, and a reduction of HCC risk, but lifelong treatments are required. A better understanding of HBV replication cycle and the host immune response will likely improve the identification of new targets for drug development. Studies are ongoing to determine if it is possible to successfully combine direct-acting antivirals (DAA) with an immunomodulatory therapy to allow increased cure rates. This review will start with summarizing the HBV replication cycle, recall current treatments, and then discuss potential targets and antiviral approaches in development to optimistically reach the HBV cure.

New Treatment Options in Chronic Hepatitis B: How Close Are We to Cure?

Hepatitis B virus (HBV) infection is the leading cause of chronic liver disease worldwide. HBV-infected patients are at a lifetime risk of developing liver cirrhosis and hepatocellular carcinoma (HCC). Today, pegylated interferon (Peg-IFN) and nucleos(t)ide analogs (NAs) are used in the treatment of patients with chronic hepatitis B (CHB). Both treatment options have limitations. Despite effective viral suppression, NAs have little effect on covalently closed circular DNA (cccDNA), the stable episomal form of the HBV genome in hepatocytes. Therefore, the cure rate with NAs is low, and long-term treatment is required. Although the cure rate is better with Peg-IFN, it is difficult to tolerate due to drug side effects. Therefore, new treatment options are needed in the treatment of HBV infection. We can group new treatments under two headings: those that interfere with the viral life cycle and spread and those that modulate the immune response. Clinical studies show that combinations of treatments that directly target the viral life cycle and treatments that regulate the host immune system will be among the important treatment strategies in the future. As new direct-acting antiviral (DAA) and immunomodulatory therapies continue to emerge and evolve, functional cures in HBV treatment may be an achievable goal.

Long-Term Hepatitis B Surface Antigen Profile and Seroclearance Following Antiviral Treatment: A Single-Center, Real-World Cohort Study

Hepatitis B surface antigen (HBsAg) seroclearance, an indicator of recovery from hepatitis B virus (HBV) infection, is uncommon in long-term nucleos(t)ide analog (NUC) therapy. We compared the incidence of HBsAg seroclearance in patients with and without NUC discontinuation to identify predictors of HBsAg seroclearance. This retrospective study enrolled adult patients with a chronic HBV infection followed for ≥12 months after NUC discontinuation (finite group) and those treated with NUCs for >3 years (non-finite group). Demographic, clinical, and laboratory data were analyzed. The study cohort included 978 patients, including 509 and 469 patients in the finite and non-finite groups, respectively. Cumulative HBsAg seroclearance incidence was significantly higher in the finite group than in the non-finite group (p = 0.006). The 5- and 10-year cumulative HBsAg seroclearance incidence were 6.6% and 18.9% in the finite group and 3% and 14.6% in the non-finite group, respectively. The likelihood of HBsAg seroclearance was higher in those with end of treatment (EOT) HBsAg levels of <100 IU/mL and in those without clinical relapse (CR). The cumulative 3-year CR incidence was 16.8%. The incidence of liver decompensation and hepatocellular carcinoma were 4.1 and 0.4 per 1000 person-years, respectively. The hepatocellular carcinoma incidence did not significantly differ between the finite and non-finite groups (p = 0.941). In conclusion, higher HBsAg seroclearance incidence in patients receiving finite therapy, and the increased likelihood of HBsAg seroclearance in those with EOT HBsAg levels of <100 IU/mL and in those without CR should be considered during decision-making of treatment options.

What is the Path Forward to Treat Hepatitis Delta Virus?: Old Treatments and New Options

HDV use the cell enzymes for its own replication, and the HBsAg as an envelope. There is an urgent need to develop new drugs for chronic hepatitis D (CHD). Pegylated interferon alpha (PEG-IFNα) (direct-antiviral and immune modulator) has been used and recommended by scientific guidelines, although not approved, with moderate efficacy and poor tolerability. There are several drugs in development which target the host: bulevirtide (BLV), lonafarnib (LNF), nucleic acid polymer, and others.

Guidance on treatment endpoints and study design for clinical trials aiming to achieve cure in chronic hepatitis B and D: Report from the 2022 AASLD-EASL HBV-HDV Treatment Endpoints Conference

Representatives from academia, industry, regulatory agencies, and patient advocacy groups convened under the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) in June 2022 with the primary goal of achieving consensus on chronic HBV and HDV treatment endpoints to guide clinical trials aiming to "cure" HBV and HDV. Conference participants reached an agreement on some key points. The preferred primary endpoint for phase II/III trials evaluating finite treatments for chronic hepatitis B (CHB) is a "functional" cure, defined as sustained HBsAg loss and HBV DNA less than the lower limit of quantitation (LLOQ) 24 weeks off-treatment. An alternate endpoint would be "partial cure" defined as sustained HBsAg level <100 IU/mL and HBV DNA Collapse

Key Words

• HBV
• HDV
• diagnosis

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MESH Headings Collapse

Grants

• 001 World Health Organization

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Affiliation(s) Collapse

Overview of New Targets for Hepatitis B Virus: Immune Modulators, Interferons, Bifunctional Peptides, Therapeutic Vaccines and Beyond

Nucleos(t)ide analogs are the cornerstone of treatment against hepatitis B virus; however, they have no direct effect on its transcriptional template (ie, covalently closed circular DNA) and so functional cure is rarely achieved. Over recent years, there has been a significant improvement in our understanding of the viral life cycle and its mechanisms of immune evasion. In this review article, we will explore novel therapeutic targets, discuss the latest data from clinical trials, and highlight future research priorities.

Localization of unlabeled bepirovirsen antisense oligonucleotide in murine tissues using in situ hybridization and CARS imaging

Current methods for detecting unlabeled antisense oligonucleotide (ASO) drugs rely on immunohistochemistry (IHC) and/or conjugated molecules, which lack sufficient sensitivity, specificity, and resolution to fully investigate their biodistribution. Our aim was to demonstrate the qualitative and quantitative distribution of unlabeled bepirovirsen, a clinical stage ASO, in livers and kidneys of dosed mice using novel staining and imaging technologies at subcellular resolution. ASOs were detected in formalin-fixed paraffin-embedded (FFPE) and frozen tissues using an automated chromogenic in situ hybridization (ISH) assay: miRNAscope. This was then combined with immunohistochemical detection of cell lineage markers. ASO distribution in hepatocytes versus nonparenchymal cell lineages was quantified using HALO AI image analysis. To complement this, hyperspectral coherent anti-Stokes Raman scattering (HS-CARS) imaging microscopy was used to specifically detect the unique cellular Raman spectral signatures following ASO treatment. Bepirovirsen was localized primarily in nonparenchymal liver cells and proximal renal tubules. Codetection of ASO with distinct cell lineage markers of liver and kidney populations aided target cell identity facilitating quantification. Positive liver signal was quantified using HALO AI, with 12.9% of the ASO localized to the hepatocytes and 87.1% in nonparenchymal cells. HS-CARS imaging specifically detected ASO fingerprints based on the unique vibrational signatures following unlabeled ASO treatment in a totally nonperturbative manner at subcellular resolution. Together, these novel detection and imaging modalities represent a significant increase in our ability to detect unlabeled ASOs in tissues, demonstrating improved levels of specificity and resolution. These methods help us understand their underlying mechanisms of action and ultimately improve the therapeutic potential of these important drugs for treating globally significant human diseases.

RNA binding protein TIAR modulates HBV replication by tipping the balance of pgRNA translation

The pregenomic RNA (pgRNA) of hepatitis B virus (HBV) serves not only as a bicistronic message RNA to translate core protein (Cp) and DNA polymerase (Pol), but also as the template for reverse transcriptional replication of viral DNA upon packaging into nucleocapsid. Although it is well known that pgRNA translates much more Cp than Pol, the molecular mechanism underlying the regulation of Cp and Pol translation efficiency from pgRNA remains elusive. In this study, we systematically profiled HBV nucleocapsid- and pgRNA-associated cellular proteins by proteomic analysis and identified TIA-1-related protein (TIAR) as a novel cellular protein that binds pgRNA and promotes HBV DNA replication. Interestingly, loss- and gain-of-function genetic analyses showed that manipulation of TIAR expression did not alter the levels of HBV transcripts nor the secretion of HBsAg and HBeAg in human hepatoma cells supporting HBV replication. However, Ribo-seq and PRM-based mass spectrometry analyses demonstrated that TIAR increased the translation of Pol but decreased the translation of Cp from pgRNA. RNA immunoprecipitation (RIP) and pulldown assays further revealed that TIAR directly binds pgRNA at the 5' stem-loop (ε). Moreover, HBV replication or Cp expression induced the increased expression and redistribution of TIAR from the nucleus to the cytoplasm of hepatocytes. Our results thus imply that TIAR is a novel cellular factor that regulates HBV replication by binding to the 5' ε structure of pgRNA to tip the balance of Cp and Pol translation. Through induction of TIAR translocation from the nucleus to the cytoplasm, Cp indirectly regulates the Pol translation and balances Cp and Pol expression levels in infected hepatocytes to ensure efficient viral replication.

Efficacy and safety of the siRNA JNJ-73763989 and the capsid assembly modulator JNJ-56136379 (bersacapavir) with nucleos(t)ide analogues for the treatment of chronic hepatitis B virus infection (REEF-1): a multicentre, double-blind, active-controlled, randomised, phase 2b trial

BACKGROUND

JNJ-73763989 (JNJ-3989), a small interfering RNA, targets all hepatitis B virus (HBV) RNAs, reducing all HBV proteins. JNJ-56136379 (JNJ-6379; also known as bersacapavir), a capsid assembly modulator, inhibits HBV replication. We aimed to evaluate the efficacy (ie, antiviral activity) and safety of these therapeutics in combination with nucleos(t)ide analogues in patients with chronic hepatitis B.

METHODS

The REEF-1 multicentre, double-blind, active-controlled, randomised, phase 2b study was done at 108 hospitals or outpatient centres across 19 countries in Asia, Europe, and North and South America. We included patients aged 18-65 years with chronic hepatitis B (defined as HBsAg positivity at screening and at least 6 months before screening or alternative markers of chronicity [eg, HBV DNA]), including those not currently treated, virologically suppressed, HBeAg positive, and HBeAg negative. Patients were randomly assigned (1:1:2:2:2:2) via permuted block randomisation according to a computer-generated schedule to receive oral nucleos(t)ide analogues once per day plus placebo (control group); oral JNJ-6379 250 mg daily plus nucleos(t)ide analogues (JNJ-6379 dual group); nucleos(t)ide analogues plus subcutaneously injected JNJ-3989 at doses of 40 mg (JNJ-3989 dual 40 mg group), 100 mg (JNJ-3989 dual 100 mg group), or 200 mg (JNJ-3989 dual 200 mg group) every 4 weeks; or JNJ-6379 250 mg plus JNJ-3989 100 mg every 4 weeks plus nucleos(t)ide analogues (triple group) for 48 weeks followed by a follow-up phase. An interactive web response system provided concealed treatment allocation, and investigators remained masked to the intervention groups until the primary analysis at week 48. The primary endpoint was the proportion of patients meeting predefined nucleos(t)ide analogue-stopping criteria (alanine aminotransferase <3 × upper limit of normal, HBV DNA below the lower limit of quantitation, HBeAg negative, and HBsAg <10 IU/mL) at week 48. All patients who received at least one dose of study drug were included in the analysis population used for primary efficacy assessment, excluding those who withdrew because of COVID-19-related reasons, withdrew before week 44, or had no efficacy data (ie, the modified intention-to-treat population). Safety was assessed in all participants who received at least one dose of study drugs. This trial is registered with ClinicalTrials.gov, NCT03982186. The study has been completed.

FINDINGS

Between Aug 1, 2019, and April 26, 2022, 470 patients (310 [66%] male and 244 [52%] White) were randomly assigned: 45 to the control group, 48 to the JNJ-6379 dual group, 93 to the JNJ-3989 dual 40 mg group, 93 to the JNJ-3989 dual 100 mg group, 96 to the JNJ-3989 dual 200 mg group, and 95 to the triple group. At week 48, five (5%; 90% CI 2-11) of 91 patients in the JNJ-3989 dual 40 mg group, 15 (16%; 10-24) of 92 in the JNJ-3989 dual 100 mg group, 18 (19%; 13-27) of 94 in the JNJ-3989 dual 200 mg group, eight (9%; 4-15) of 94 in the triple group, and one (2%; 0-10) of 45 in the control group met nucleos(t)ide analogue stopping criteria. No patients in the JNJ-6379 dual group met stopping criteria. 38 (81%) patients who met nucleos(t)ide analogue-stopping criteria at week 48 were virologically suppressed and HBeAg negative at baseline. Ten (2%) of 470 patients had serious adverse events during the treatment phase, and two patients (one each from the JNJ-3989 dual 200 mg group [exercise-related rhabdomyolysis] and the triple group [increase in ALT or AST]) had serious adverse events related to study treatment. During follow-up, 12 (3%) of 460 patients had a serious adverse event; one (<1%), a gastric ulcer, was considered to be related to nucleos(t)ide analogues and occurred in a patient from the JNJ-3989 dual 200 mg group. 29 (6%) of 460 patients in the treatment phase and in ten (2%) of 460 patients in the follow-up phase had grade 3 or 4 adverse events. Five (1%) of 470 patients discontinued treatment due to adverse events, and there were no deaths.

INTERPRETATION

Although treatment with JNJ-3989 led to a dose-dependent response for meeting nucleos(t)ide analogue-stopping criteria, it rarely led to HBsAg seroclearance. However, most patients treated with JNJ-3989 had clinically meaningful reductions in HBsAg that might contribute to a liver environment conducive to better immune control and, in turn, might improve the response to immune-modulating therapies.

FUNDING

Janssen Research and Development.

B-Clear Phase 2b Study Design: Establishing the Efficacy and Safety of Bepirovirsen in Patients with Chronic Hepatitis B Virus Infection

INTRODUCTION

Bepirovirsen (GSK3228836) is an antisense oligonucleotide that induced rapid and prolonged hepatitis B surface antigen (HBsAg) reduction with a favorable safety profile following 4 weeks of treatment in participants with chronic hepatitis B virus (HBV) infection. The objective of the phase 2b study B-Clear is to access the efficacy and safety of bepirovirsen in participants with chronic HBV infection.

METHODS

B-Clear is a phase 2b, multicenter, randomized, partial-blind (sponsor/participant-blinded, investigator-unblinded) study in participants with chronic HBV infection receiving stable nucleos(t)ide analogue (On-NA) or not currently receiving NA therapy (Not-on-NA). Eligibility criteria included HBsAg > 100 IU/mL, HBV DNA < 90 IU/mL (On-NA) or > 2000 IU/mL (Not-on-NA), and alanine aminotransferase ≤ 2 × upper limit of normal (ULN; On-NA) or < 3 × ULN (Not-on-NA). Participants were randomized 3:3:3:1 to one of four treatment arms, with treatment administered weekly as subcutaneous injections with or without loading doses (LD) on days 4 and 11: bepirovirsen 300 mg (with 300 mg LD) for 24 weeks; bepirovirsen 300 mg (with 300 mg LD) for 12 weeks then bepirovirsen 150 mg for 12 weeks; bepirovirsen 300 mg (with 300 mg LD) for 12 weeks then placebo for 12 weeks; placebo for 12 weeks (with placebo LD) then bepirovirsen 300 mg without LD for 12 weeks.

PLANNED OUTCOMES

The primary endpoint of the study was HBsAg < lower limit of detection and HBV DNA < lower limit of quantification for 24 weeks after the end of bepirovirsen treatment in the absence of rescue medication. The study enrolled 457 participants (On-NA, n = 227; Not-on-NA, n = 230) and the last patient visit occurred in March 2022. The novel design of the B-Clear study will allow assessment of HBsAg and HBV DNA seroclearance post bepirovirsen treatment discontinuation in the presence and absence of background NA therapy.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04449029; GSK study 209668).

EASL Clinical Practice Guidelines on hepatitis delta virus

Hepatitis D virus (HDV) is a defective virus that requires the hepatitis B virus to complete its life cycle and cause liver damage in humans. HDV is responsible for rare acute and chronic liver diseases and is considered the most aggressive hepatitis virus. Acute infection can cause acute liver failure, while persistent infection typically causes a severe form of chronic hepatitis which is associated with rapid and frequent progression to cirrhosis and its end-stage complications, hepatic decompensation and hepatocellular carcinoma. Major diagnostic and therapeutic innovations prompted the EASL Governing Board to commission specific Clinical Practice Guidelines on the identification, virologic and clinical characterisation, prognostic assessment, and appropriate clinical and therapeutic management of HDV-infected individuals.

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.

The future of hepatology

The field of hepatology has made impressive progress over its ~75 years of existence. Advances in understanding liver function and its dysregulation in disease, genetic determinants of disease, antiviral therapy, and transplantation have transformed the lives of patients. However, there are still significant challenges that require ongoing creativity and discipline, particularly with the emergence of fatty liver diseases, as well as managing autoimmune disease, cancer, and liver disease in children. Diagnostic advances are urgently needed to accelerate risk stratification and efficient testing of new agents with greater precision in enriched populations. Integrated, holistic care models should be extended beyond liver cancer to diseases like NAFLD with systemic manifestations or extrahepatic comorbidities such as cardiovascular disease, diabetes, addiction, and depressive disorders. To meet the growing burden of asymptomatic liver disease, the workforce will need to be expanded by incorporating more advanced practice providers and educating other specialists. The training of future hepatologists will benefit from incorporating emerging skills in data management, artificial intelligence, and precision medicine. Continued investment in basic and translational science is crucial for further progress. The challenges ahead are significant, but with collective effort, the field of hepatology will continue to make progress and overcome obstacles.

Past, present, and future of long-term treatment for hepatitis B virus

The estimated world prevalence of hepatitis B virus (HBV) infection is 316 million. HBV infection was identified in 1963 and nowadays is a major cause of cirrhosis and hepatocellular carcinoma (HCC) despite universal vaccination programs, and effective antiviral therapy. Long-term administration of nucleos(t)ide analogues (NA) has been the treatment of choice for chronic hepatitis B during the last decades. The NA has shown a good safety profile and high efficacy in controlling viral replication, improving histology, and decreasing the HCC incidence, decompensation, and mortality. However, the low probability of HBV surface antigen seroclearance made necessary an indefinite treatment. The knowledge, in recent years, about the different phases of the viral cycle, and the new insights into the role of the immune system have yielded an increase in new therapeutic approaches. Consequently, several clinical trials evaluating combinations of new drugs with different mechanisms of action are ongoing with promising results. This integrative literature review aims to assess the knowledge and major advances from the past of hepatitis B, the present of NA treatment and withdrawal, and the future perspectives with combined molecules to achieve a functional cure.

New Perspectives on Development of Curative Strategies for Chronic Hepatitis B

A functional cure of chronic hepatitis B defined as sustained hepatitis B surface antigen loss after finite course of therapy is rarely achieved with current therapy but is the goal of novel treatments. Understanding the virological and immunological mechanisms of hepatitis B virus persistence has enabled the identification of novel treatment targets, drug discovery, and the evaluation of novel agents in clinical trials. Lessons were learned from early phase 1 and phase 2 trials regarding the antiviral activity and safety profile of these agents. There is a strong rationale to combine agents to reduce viral replication, reduce viral antigen load, invigorate immune responses, and induce specific adaptive immune responses. Nucleos(t)ide analogs will likely remain an essential backbone of future combinations to control viral replication and prevent resistance to antiviral drugs. In this review, we discuss perspectives on approaches to achieving functional cure, with a review of virological and immunological strategies, highlighting challenges and unresolved questions with the various attempts to achieve cure, as well as exploring alternative endpoints such as partial cure and new noninvasive viral and immunological biomarkers to stratify patients and predict/monitor antiviral response.

A role for immune modulation in achieving functional cure for chronic hepatitis B among current changes in the landscape of new treatments

INTRODUCTION

Chronic hepatitis B (CHB) is rarely cured using available treatments. Barriers to cure are: 1) persistence of reservoirs of hepatitis B virus (HBV) replication and antigen production (HBV DNA); 2) high burden of viral antigens that promote T cell exhaustion with T cell dysfunction; 3) CHB-induced impairment of immune responses.

AREAS COVERED

We discuss options for new therapies that could address one or more of the barriers to functional cure, with particular emphasis on the potential role of immunotherapy.

EXPERT OPINION/COMMENTARY

Ideally, a sterilizing cure for CHB would translate into finite therapies that result in loss of HBV surface antigen and eradication of HBV DNA. Restoration of a functional adaptive immune response, a key facet of successful CHB treatment, remains elusive. Numerous strategies targeting the high viral DNA and antigen burden and aiming to restore the host immune responses will enter clinical development in coming years. Most patients are likely to require combinations of several drugs, personalized according to virologic and disease characteristics, patient preference, accessibility, and affordability. The management of CHB is a global health priority. Expedited drug development requires collaborations between regulatory agencies, scientists, clinicians, and within the industry to facilitate testing of the best drug combinations.