Peginterferon alpha-2a (40 kDa): an advance in the treatment of hepatitis B e antigen-positive chronic hepatitis B

Type I and type III interferons: From basic biology and genetics to clinical development for COVID-19 and beyond

Type I and type III interferons (IFNs) constitute a key antiviral defense systems of the body, inducing viral resistance to cells and mediating diverse innate and adaptive immune functions. Defective type I and type III IFN responses have recently emerged as the 'Achilles heel' in COVID-19, with such patients developing severe disease and exhibiting a high risk for critical pneumonia and death. Here, we review the biology of type I and type III IFNs, their similarities and important functional differences, and their roles in SARS-CoV-2 infection. We also appraise the various mechanisms proposed to drive defective IFN responses in COVID-19 with particular emphasis to the ability of SARS-CoV-2 to suppress IFN production and activities, the genetic factors involved and the presence of autoantibodies neutralizing IFNs and accounting for a large proportion of individuals with severe COVID-19. Finally, we discuss the long history of the type I IFN therapeutics for the treatment of viral diseases, cancer and multiple sclerosis, the various efforts to use them in respiratory infections, and the newly emerging type III IFN therapeutics, with emphasis to the more recent studies on COVID-19 and their potential use as broad spectrum antivirals for future epidemics or pandemics.

Sequential Therapy with Ropeginterferon Alfa-2b and Anti-Programmed Cell Death 1 Antibody for Inhibiting the Recurrence of Hepatitis B-Related Hepatocellular Carcinoma: From Animal Modeling to Phase I Clinical Results

Hepatocellular carcinoma (HCC) usually recurs after curative surgical resection. Currently, no approved adjuvant therapy has been shown to reduce HCC recurrence rates. In this study, the in vivo effect of sequential combination treatment with recombinant mouse interferon-alpha (rmIFN-α) and an anti-mouse-PD1 antibody on hepatitis B virus (HBV) clearance in mice was evaluated. A Phase I clinical trial was then conducted to assess the safety, tolerability, and inhibitory activity of sequential therapy with ropeginterferon alfa-2b and nivolumab in patients with HCC recurrence who underwent curative surgery for HBV-related HCC. The animal modeling study showed that HBV suppression was significantly greater with the rmIFN-α and anti-PD1 sequential combination treatment in comparison with sole treatment with rmIFN-α or anti-PD1. In the Phase I study, eleven patients completed the sequential therapy with ropeginterferon alfa-2b every two weeks for six doses at 450 µg, followed by three doses of nivolumab every two weeks up to 0.75 mg/kg. A notable decrease in or clearance of HBV surface antigen was observed in two patients. The dose-limiting toxicity of grade 3 alanine transaminase and aspartate aminotransferase increases was observed in one patient. The maximum tolerated dose was then determined. To date, no HCC recurrence has been observed. The treatment modality was well tolerated. These data support the further clinical development of sequential combination therapy as a post-surgery prophylactic measure against the recurrence of HBV-related HCC.

Diagnosis and Management of Hepatitis Delta Virus Infection

Hepatitis D virus (HDV) depends on hepatitis B virus (HBV) to enter and exit hepatocytes and to replicate. Despite this dependency, HDV can cause severe liver disease. HDV accelerates liver fibrosis, increases the risk of hepatocellular carcinoma, and hastens hepatic decompensation compared to chronic HBV monoinfection. The Chronic Liver Disease Foundation (CLDF) formed an expert panel to publish updated guidelines on the testing, diagnosis, and management of hepatitis delta virus. The panel group performed network data review on the transmission, epidemiology, natural history, and disease sequelae of acute and chronic HDV infection. Based on current available evidence, we provide recommendations for screening, testing, diagnosis, and treatment of hepatitis D infection and review upcoming novel agents that may expand treatment options. The CLDF recommends universal HDV screening for all patients who are Hepatitis B surface antigen-positive. Initial screening should be with an assay to detect antibodies generated against HDV (anti-HDV). Patients who are positive for anti-HDV IgG antibodies should then undergo quantitative HDV RNA testing. We also provide an algorithm that describes CLDF recommendations on the screening, diagnosis, testing, and initial management of Hepatitis D infection.

Developments in pharmacotherapeutic agents for hepatitis B - how close are we to a functional cure?

INTRODUCTION

Hepatitis B virus (HBV) remains a public health concern given its global prevalence and potential complications including hepatocellular carcinoma (HCC). Current therapies, including nucleos(t)ide analogs (NA) and interferons (IFN), are effective in chronic treatment of HBV but rarely provide a functional cure due to inadequate host response and the presence of viral DNA. Therefore, novel therapies that enhance the innate immune response while suppressing DNA transcription may provide definitive treatment of HBV.

AREAS COVERED

In this review, the authors provide a brief overview of commonly used agents and their efficacy in treatment of HBV. Newer therapies with direct antiviral agents such as bepirovirsen (antisense oligonucleotide (ASO)) and entry inhibitors such as bulevirtide have shown efficacy in reducing viral load but demonstrate further reductions in conjunction with immune modulators such as therapeutic vaccines.

EXPERT OPINION

Combination therapy is far superior to monotherapy alone, necessitating the need for both immunomodulators and direct antiviral agents in chronic treatment of HBV. Therapies that target covalently closed circular (cccDNA) with immunomodulators like therapeutic vaccines have shown promising results and may ultimately achieve functional cure. However, therapies need to be evaluated in the context of the patient, considering both financial and socioeconomic factors.

Interferon and interferon-stimulated genes in HBV treatment

Human hepatitis B virus (HBV) is a small enveloped DNA virus with a complex life cycle. It is the causative agent of acute and chronic hepatitis. HBV can resist immune system responses and often causes persistent chronic infections. HBV is the leading cause of liver cancer and cirrhosis. Interferons (IFNs) are cytokines with antiviral, immunomodulatory, and antitumor properties. IFNs are glycoproteins with a strong antiviral activity that plays an important role in adaptive and innate immune responses. They are classified into three categories (type I, II, and III) based on the structure of their cell-surface receptors. As an effective drug for controlling chronic viral infections, Type I IFNs are approved to be clinically used for the treatment of HBV infection. The therapeutic effect of interferon will be enhanced when combined with other drugs. IFNs play a biological function by inducing the expression of hundreds of IFN-stimulated genes (ISGs) in the host cells, which are responsible for the inhibiting of HBV replication, transcription, and other important processes. Animal models of HBV, such as chimpanzees, are also important tools for studying IFN treatment and ISG regulation. In the present review, we summarized the recent progress in IFN-HBV treatment and focused on its mechanism through the interaction between HBV and ISGs.

Entry inhibition of hepatitis B virus using cyclosporin O derivatives with peptoid side chain incorporation

Hepatitis B virus (HBV) infection is a serious worldwide health problem causing liver cirrhosis and hepatocellular carcinoma. The development of novel therapeutics targeting distinct steps of the HBV life cycle and combination therapy with approved drugs (i.e., nucleot(s)ides, interferon-α) are considered effective strategies for curing HBV. Among these strategies is the development of entry inhibitors that interfere with the host entry step of HBV to prevent viral infection and transmission. Herein, we generated a novel library of cyclosporin O (CsO) derivatives that incorporate peptoid side chains. Twenty-two CsO derivatives were evaluated for membrane permeability, cytotoxicity, and in vitro HBV entry inhibitory activity. The lead compound (i.e., compound 21) showed the greatest potency in the in vitro HBV entry inhibition assay (IC₅₀ = 0.36 ± 0.01 μM) with minimal cytotoxicity. Our peptide-peptoid hybrid CsO scaffold can readily expand chemical diversity and is applicable for screening various targets requiring macrocyclic chemical entities.

Pegylated Interferon Alpha for Chronic Hepatitis B Virus Infection

Chronic hepatitis B (CHB) is a potentially life-threatening and prevalent disease worldwide. Far from attaining the ultimate treatment goal, hepatitis B virus (HBV) infection eradication, the two current therapeutic options aim to prevent progression to end-stage liver disease, maintaining long-term suppression of HBV replication. Pegylated interferon-α (PEG-INFα) is often poorly tolerated and disregarded considering the orally administered nucleos(t)ide analogues. However, PEG-INFα may achieve similar treatment endpoints with a finite course of treatment. We report a case of PEG-INFα-treated CHB that attained sustained off-treatment virological response with only 16 weeks of treatment, with loss of both HBeAg and HBsAg (this latter the optimal treatment endpoint).

Interpretation of HBV Serologies

Hepatitis B was discovered by researchers who were investigating jaundice associated with blood transfusions as well as parenterally administered medications. Through trial and error, the HBV was identified. There are specific tests that detect HBV infection, whether it is a previous exposure or active infection. The various HBV serologies are reviewed in this work as well. Hepatitis B surface antigen has emerged as a tool in defining treatment endpoint and its significance is reviewed. HBV genotypes are distributed uniquely throughout the world, in particular, genotype C is associated with higher rates of hepatocellular carcinoma. Various HBV genotypes and their impact on the clinical course are discussed. The relationship of HBV serologies and HBV DNA to disease progression is outlined. There are specific recommendations on monitoring those infected with HBV and this is reviewed here. HBV mutations have an impact on the disease course and those of significance are also discussed.

HBV/HIV Coinfection: Impact on the Development and Clinical Treatment of Liver Diseases

Hepatitis B virus (HBV) infection is a common contributor to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Approximately 10% of people with human immunodeficiency virus (HIV) also have chronic HBV co-infection, owing to shared transmission routes. HIV/HBV coinfection accelerates the progression of chronic HBV to cirrhosis, end-stage liver disease, or hepatocellular carcinoma compared to chronic HBV mono-infection. HBV/HIV coinfection alters the natural history of hepatitis B and renders the antiviral treatment more complex. In this report, we conducted a critical review on the epidemiology, natural history, and pathogenesis of liver diseases related to HBV/HIV coinfection. We summarized the novel therapeutic options for these coinfected patients.

Visualizing and quantifying antimicrobial drug distribution in tissue

The biodistribution and pharmacokinetics of drugs are vital to the mechanistic understanding of their efficacy. Measuring antimicrobial drug efficacy has been challenging as plasma drug concentration is used as a surrogate for tissue drug concentration, yet typically does not reflect that at the intended site(s) of action. Utilizing an image-guided approach, it is feasible to accurately quantify the biodistribution and pharmacokinetics within the desired site(s) of action. We outline imaging modalities used in visualizing drug distribution with examples ranging from in vitro cellular drug uptake to clinical treatment of microbial infections. The imaging modalities of interest are: radio-labeling, magnetic resonance, mass spectrometry imaging, computed tomography, fluorescence, and Raman spectroscopy. We outline the progress, limitations, and future outlook for each methodology. Further advances in these optical approaches would benefit patients and researchers alike, as non-invasive imaging could yield more profound insights with a lower clinical burden than invasive measurement approaches used today.

Outcome of Chinese patients with hepatitis B at 96 weeks after functional cure with IFN versus combination regimens

BACKGROUND & AIMS

Nucleotides with add-on interferon treatment (NUC-IFN) provide significantly higher rates of hepatitis B surface antigen (HBsAg) loss in patients with chronic hepatitis B (CHB). This study aimed to investigate the sustainability of HBsAg loss and the prevention of clinical relapse.

METHODS

Patients with CHB who achieved HBsAg loss and HBV DNA levels <20 IU/ml after IFN or NUC-IFN therapy were enrolled and followed up for 96 weeks. The primary outcome was HBsAg negativity without viremia at week 96. Secondary outcomes included virological or clinical relapse and predictors of relapse.

RESULTS

420 patients were included in intention-to-treat analysis with 290 and 130 in the IFN and NUC-IFN groups respectively. At week 96, the intention-to-treat analysis revealed similar outcomes between groups, including HBsAg seroreversion (24.83% vs. 23.08%, P = .70), viremia (16.90% vs 13.08%, P = .32) and clinical relapse (11.38% vs 10.00%, P = .68); the per-protocol analyses also showed HBsAg seroreversion, viremia and clinical relapse in IFN group (15.50%, 6.59% and 0.39%) did not differ from those in NUC-IFN group (15.25%, 4.24% and 0.85%, P > .05). These outcomes were similar between patients who received entecavir and those who received telbivudine/lamivudine/adefovir before the combination therapy. In NUC-IFN-treated patients, fibrosis regression was observed at week 96. Baseline HBsAb negativity was independent predictors of HBsAg sero-reversion and recurrence of viremia in IFN treated group.

CONCLUSION

NUC-IFN and IFN therapies are equally effective in achieving sustained functional cure and fibrosis regression. (ClinicalTrials.gov, Number NCT02336399).

Recent Advances in the Treatment of Hemophilia: A Review

Progress in hemophilia therapy has been remarkable in the first 20 years of the third millennium, but the innovation began with the description the fractionation of plasma in 1946. The first concentrates followed the discovery of FVIII in the cryoprecipitate of frozen plasma and FIX in the supernatant in the early 1960s, which led to the initial attempts at replacement therapy. Unfortunately, the lack of screening methods for viral pathogens resulted in people with hemophilia (PWH) receiving concentrates contaminated by hepatitis A virus, hepatitis C virus, and human immunodeficiency virus, as these concentrates were made from large industrial pools of plasma derived from thousands of donors. Fortunately, by 1985, viral screening methods and proper virucidal techniques were developed that made concentrates safe. Increasingly pure products followed the introduction of chromatography steps with monoclonal antibodies in the production process. The problem of immunogenicity of exogenously administered concentrates has not yet had a complete solution. The development of alloantibodies against FVIII in about 25-35% of PWH is the most serious adverse effect of replacement therapy. The next major advance followed the cloning of the F8 gene and later the F9 genes, which paved the way to produce concentrates of factors obtained by the recombinant DNA technology. The injected FVIII and FIX molecules had a relatively short circulating half-life in the plasma of people with hemophilia A and B, approximately 12 and 18 hours, respectively. The ability to prolong the plasma half-life and extend the interval between injections followed the application of methods to conjugate the factor molecule with the fragment crystallizable of IgG1 or albumin or by adding polyethylene glycol, which has led to an increase in the half-life of concentrates, especially for rFIX. The next frontier in hemophilia therapy is the application of durable and potentially curative therapies such as with gene addition therapy. Experiments in hemophilia B have demonstrated durable responses. Unfortunately, the results with gene therapy for hemophilia A have not been as remarkable and the durability must still be demonstrated. Nonetheless, the long-term safety, predictability, durability, and efficacy of gene therapy for hemophilia A and B remain an open question. At present, only healthy adult PWH have been enrolled in gene therapy clinical trials. The application of gene therapy to children and those with pre-existing antibodies against the delivery vector must also be studied before this therapy becomes widespread.

Therapeutic and Prophylactic Use of Oral, Low-Dose IFNs in Species of Veterinary Interest: Back to the Future

Cytokines are important molecules that orchestrate the immune response. Given their role, cytokines have been explored as drugs in immunotherapy in the fight against different pathological conditions such as bacterial and viral infections, autoimmune diseases, transplantation and cancer. One of the problems related to their administration consists in the definition of the correct dose to avoid severe side effects. In the 70s and 80s different studies demonstrated the efficacy of cytokines in veterinary medicine, but soon the investigations were abandoned in favor of more profitable drugs such as antibiotics. Recently, the World Health Organization has deeply discouraged the use of antibiotics in order to reduce the spread of multi-drug resistant microorganisms. In this respect, the use of cytokines to prevent or ameliorate infectious diseases has been highlighted, and several studies show the potential of their use in therapy and prophylaxis also in the veterinary field. In this review we aim to review the principles of cytokine treatments, mainly IFNs, and to update the experiences encountered in animals.

Comparison of fibrosis regression of entecavir alone or combined with pegylated interferon alpha2a in patients with chronic hepatitis B

BACKGROUND AND AIMS

Antiviral treatment with necleos(t)ide analogues contributes to histological improvement and virologic response in chronic hepatitis B (CHB) patients. However, whether adding pegylated interferon alpha2a (Peg-IFN-α-2a) can help additional clinical benefit, particularly on fibrosis regression was still unknown.

METHODS

Chronic hepatitis B patients with pre-treatment biopsy-proven Ishak fibrosis score 2, 3 or 4 were randomly assigned to entecavir (ETV) alone or ETV plus Peg-IFN-α-2a (Peg-IFN-α-2a add-on) group (1:2 ratio). Post-treatment liver biopsy was performed at week 78. Fibrosis regression was defined as decrease in Ishak fibrosis score by ≥ 1 stage or predominantly regressive categorized by P-I-R score. Serum HBV DNA levels were assessed at baseline and every 26 weeks, while HBsAg and HBeAg were evaluated at baseline and every 52 weeks.

RESULTS

A total of 218 treatment-naive CHB patients were randomly assigned to ETV alone or Peg-IFN-α-2a add-on group. Totals of 155 patients (ETV alone: Peg-IFN-α-2a add-on, 47:108) were included in statistical analysis. Fibrosis regression rates were 68% (32/47) in the ETV alone and 56% (60/108) in Peg-IFN-α-2a add-on group (p = 0.144). Both groups showed a similar trend of virological suppression during the process of 104-week antiviral therapy (p = 0.132). HBeAg or HBsAg loss or seroconversion rates in the ETV alone group were lower than Peg-IFN-α-2a add-on group though without statistical significance.

CONCLUSIONS

Peg-IFN-α-2a add-on therapy did not yield additional fibrosis regression and virologic response than ETV alone therapy.

Factors Associated with Hepatitis B Surface Antigen Kinetics and Responses in Pegylated Interferon Alpha-2a Monotherapy for Patients with Chronic Hepatitis B

Objective Pegylated-interferon monotherapy is the standard treatment for patients with chronic hepatitis B; however, the factors associated with its therapeutic effects remain unclear. Methods Patients with chronic hepatitis B were treated with pegylated interferon α-2a for 48 weeks. We evaluated the kinetics of hepatitis B surface antigen (HBsAg) during treatment and follow-up periods and the factors associated with an HBsAg response (defined as a change in HBsAg of ≥-1 log IU/mL from baseline). Results The study population comprised 50 patients. The median baseline levels of hepatitis B virus DNA and HBsAg were 5.00 and 3.40 log IU/mL. The median values of HBsAg reduction from baseline were -0.44 (n=48), -0.41 (n=40), and -0.68 (n=11) log IU/mL at the end of treatment and at 48 and 144 weeks post-treatment, respectively. The rates of HBsAg response were 24.0% and 22.5% at the end of treatment and at 48 weeks post-treatment, respectively. A multivariate analysis identified HBsAg <3.00 log IU/mL as an independent baseline factor contributing to the HBsAg response at the end of treatment and 48 weeks post-treatment (p=1.07×10^-2 and 4.42×10^-2, respectively). There were significant differences in the reduction of the HBsAg levels at 12 weeks of treatment and in the incidence of serum ALT increase during treatment between patients with and without an HBsAg response. Conclusion These findings suggest that the baseline HBsAg level, HBsAg kinetics at 12 weeks of treatment, and ALT increase during treatment are important factors contributing to the HBsAg response in pegylated interferon α-2a monotherapy for patients with chronic hepatitis B.

Importance of Type I and III Interferons at Respiratory and Intestinal Barrier Surfaces

Interferons (IFNs) constitute the first line of defense against microbial infections particularly against viruses. They provide antiviral properties to cells by inducing the expression of hundreds of genes known as interferon-stimulated genes (ISGs). The two most important IFNs that can be produced by virtually all cells in the body during intrinsic innate immune response belong to two distinct families: the type I and type III IFNs. The type I IFN receptor is ubiquitously expressed whereas the type III IFN receptor's expression is limited to epithelial cells and a subset of immune cells. While originally considered to be redundant, type III IFNs have now been shown to play a unique role in protecting mucosal surfaces against pathogen challenges. The mucosal specific functions of type III IFN do not solely rely on the restricted epithelial expression of its receptor but also on the distinct means by which type III IFN mediates its anti-pathogen functions compared to the type I IFN. In this review we first provide a general overview on IFNs and present the similarities and differences in the signal transduction pathways leading to the expression of either type I or type III IFNs. By highlighting the current state-of-knowledge of the two archetypical mucosal surfaces (e.g. the respiratory and intestinal epitheliums), we present the differences in the signaling cascades used by type I and type III IFNs to uniquely induce the expression of ISGs. We then discuss in detail the role of each IFN in controlling pathogen infections in intestinal and respiratory epithelial cells. Finally, we provide our perspective on novel concepts in the field of IFN (stochasticity, response heterogeneity, cellular polarization/differentiation and tissue microenvironment) that we believe have implications in driving the differences between type I and III IFNs and could explain the preferences for type III IFNs at mucosal surfaces.

Hepatitis B Virus: From Diagnosis to Treatment

Hepatitis B infection is still a global concern progressing as acute-chronic hepatitis, severe liver failure, and death. The infection is most widely transmitted from the infected mother to a child, with infected blood and body fluids. Pregnant women, adolescents, and all adults at high risk of chronic infection are recommended to be screened for hepatitis B infection. The initial analysis includes serological tests that allow differentiation of acute and chronic hepatitis. Molecular assays performed provide detection and quantification of viral DNA, genotyping, drug resistance, and precore/core mutation analysis to confirm infection and monitor disease progression in chronic hepatitis B patients. All patients with chronic hepatitis B should be treated with antiviral medications and regularly monitored for efficient treatment. The current treatment is based on nucleos(t)ide analogs and pegylated interferons that save lives by decreasing liver cancer death, liver transplant, slow or reverse the progression of liver disease as well as the virus infectivity.

Ropeginterferon alfa-2b every 2 weeks as a novel pegylated interferon for patients with chronic hepatitis B

Background

Ropeginterferon alfa-2b is a novel mono-pegylated interferon that has only one major form as opposed to 8–14 isomers of other on-market pegylated interferon, allowing injection every two or more weeks with higher tolerability. It received European Medicines Agency and Taiwan marketing authorization in 2019 and 2020, for treatment of polycythemia vera. This phase I/II study aimed to have preliminary evaluation of safety and efficacy in chronic hepatitis B.

Methods

Thirty-one HBeAg-positive and 31 HBeAg-negative were stratified by HBeAg status and randomized at 1:1:1 ratio to q2w ropeginterferon alfa-2b 350 μg (group 1), q2w 450 μg (group 2) or q1w PEG-IFN alfa-2a 180 μg (group 3). Each patient received 48-week treatment (TW48) and 24-week post-treatment follow-up (FW24).

Results

The baseline demographics were comparable among the three groups, except for mean HBeAg in HBeAg-positive patients (2.90, 2.23, 2.99 log₁₀ S/CO, respectively). Cumulative HBeAg seroconversion rate at follow-up period was 27.3% (3/11), 36.4% (4/11), and 11.1% (1/9) with time to HBeAg seroconversion starting from TW24, TW16, and TW48 in group 1, 2, and 3, respectively. The rate of HBV DNA < 2000 IU/mL and HBsAg levels < 1500 IU/mL at FW24 were comparable in all groups. Ropeginterferon alfa-2b (group 1 & 2) had numerically lower incidence of rash (9.5% and 4.5%) as compared to PEG-IFN alfa-2a (36.8%). Ropeginterferon alfa-2b 350 μg (group 1) had more ALT elevation (38.1%), however the rate was comparable in group 2 (9.1%) and group 3 (10.5%).

Conclusion

In this preliminary study, ropeginterferon alfa-2b, although in only half the number of injections, is as safe and effective as pegylated interferon alfa-2a for chronic hepatitis B.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s12072-020-10098-y) contains supplementary material, which is available to authorized users.

Comparison of clinical practice guidelines for the management of chronic hepatitis B: When to start, when to change, and when to stop

Clinical practice guidelines are important for guiding the management of specific diseases by medical practitioners, trainees, and nurses. In some cases, the guidelines are utilized as a reference for health policymakers in controlling diseases with a large public impact. With this in mind, practice guidelines for the management of chronic hepatitis B (CHB) have been developed in the United States, Europe, and Asian-Pacific regions to suggest the best-fit recommendations for each social and medical circumstance. Recently, the Korean Association for the Study of the Liver published a revised version of its clinical practice guidelines for the management of CHB. The guidelines included updated information based on newly available antiviral agents, the most recent opinion on the initiation and cessation of treatment, and updates for the management of drug resistance, partial virological response, and side effects. Additionally, CHB management in specific situations was comprehensively revised. This review compares the similarities and differences among the various practice guidelines to identify unmet needs and improve future recommendations.

Targeting Host Innate and Adaptive Immunity to Achieve the Functional Cure of Chronic Hepatitis B

Despite the availability of an effective preventive vaccine for hepatitis B virus (HBV) for over 38 years, chronic HBV (CHB) infection remains a global health burden with around 257 million patients. The ideal treatment goal for CHB infection would be to achieve complete cure; however, current therapies such as peg-interferon and nucleos(t)ide analogs are unable to achieve the functional cure, the newly set target for HBV chronic infection. Considering the fact functional cure has been accepted as an endpoint in the treatment of chronic hepatitis B by scientific committee, the development of alternative therapeutic strategies is urgently needed to functionally cure CHB infection. A promising target for future therapeutic strategies is immune modulation to restore dysfunctional HBV-specific immunity. In this review, we provide an overview of the progress in alternative therapeutic strategies, including immune-based therapeutic approaches that enhance host innate and adaptive immunity to achieve and increase the functional cure from CHB infection.

Hepatitis B-related glomerulonephritis and optimization of treatment

Introduction: Multiple studies have revealed a strong relationship between the development of nephropathy and hepatitis B virus (HBV) infection. The underlying pathogenesis of hepatitis B-related glomerulonephritis (HBV-GN) involves immune complexes, which can be isolated from kidney tissues. Clearance of HBV antigenemia improves renal impairment and proteinuria in HBV-GN patients.Areas covered: In this review, we present our current understanding of the epidemiology, pathogenesis, pathology, diagnosis, and treatment of HBV-GN. We discuss the advantages and disadvantages of oral nucleoside/nucleotide analogs (NAs), and the main pharmaceutical treatment for hepatis B.Expert opinion: Currently, antiviral agents are the main HBV-GN therapeutic agents. Although no randomized controlled clinical trials have compared the efficacy of interferon (IFN) and NA, we suggest IFN treatment for pediatric patients (IFN-α in patients ≥1 year; pegIFN-α in patients ≥3 years) considering treatment duration and absence of resistance. Novel NAs have brought about promising treatment options involving high efficacy viral suppression and low resistance rates. NAs with a high barrier to resistance (e.g. entecavir) are recommended as first-line therapy of HBV-GN. Immunosuppression monotherapy, such as corticosteroids, is of little benefit and potentially harmful to HBV-GN patients due to the possibility of viral reactivation.

GC-MS-based metabolomics approach to diagnose depression in hepatitis B virus-infected patients with middle or old age

Depression is concomitantly presented in hepatitis B virus (HBV)-infected patients (HB). However, there is still no objective method to diagnose HBV-infected patients with depression (dHB). Therefore, in this study, a gas chromatography-mass spectrometry (GC-MS)-based metabolomic approach was employed to profile urine samples from 59 dHB and 52 HB (the training set) in order to identify urinary metabolite biomarkers for dHB. Then, 41 dHB and 35 HB (the testing set) were used to independently validate the diagnostic generalizability of these biomarkers. In total, 13 differential metabolites responsible for the discrimination between dHB and HB were identified. These differential urinary metabolites belonged mainly to Lipid metabolism and Amino acid metabolism. A panel consisting of six urinary metabolite biomarkers (ethanolamine, azelaic acid, histidine, threitol, 2,4-dihydroxypyrimidine and levulinic acid) was identified. This panel was capable of distinguishing dHB from HB with an area under the receiver operating characteristic curve (AUC) of 0.986 in the training set. Moreover, this panel could classify blinded samples from the testing set with an AUC of 0.933. These findings indicated that the GC-MS-based metabolomics approach could be a useful tool in the clinical diagnosis of dHB, and the identified biomarkers were helpful for future developing an objective diagnostic method for dHB.

Pharmacokinetics and pharmacodynamics of pegylated interferon for the treatment of hepatitis B

Introduction: Interferon (IFN) had both antiviral and immunomodulatory effects, and was one of the approved treatments for hepatitis B virus (HBV). Herein, we reviewed the pharmacokinetics and pharmacodynamics of pegylated IFN-α (PegIFN-α) for the treatment of HBV. Areas covered: The steady-state serum levels of PegIFN-α were reached within 5 to 8 weeks, and the week 48 mean trough concentrations were approximately 2-fold higher than week 1. There was also no difference of the pharmacokinetics in male or female, healthy volunteers or patients with hepatitis B or C infection. PegIFN-α did not affect the metabolism of the cytochrome P450 (CYP) isozymes, except inhibition of CYP1A2. There was also no pharmacokinetic interaction between PegIFN-α and HBV nucleot(s)ide analogues (NUCs). Forty-eight weeks of PegIFN-α achieved 32% of HBeAg seroconversion, 32-43% of HBV DNA suppression, 41-59% of ALT normalization, and 3% of HBsAg seroconversion rate with a post-treatment durable response up to 80% in the initial responders. Expert opinion: On-treatment HBsAg titer guided the treatment of HBV with PegIFN-α. The recommendation of PegIFN-α and NUC combination or switch remained controversial. New immunotherapeutic agents are now in development. Although, PegIFN-α should continue to play a role in the treatment of HBV.

Shared and Distinct Functions of Type I and Type III Interferons

Type I interferons (IFNs) (IFN-α, IFN-β) and type III IFNs (IFN-λ) share many properties, including induction by viral infection, activation of shared signaling pathways, and transcriptional programs. However, recent discoveries have revealed context-specific functional differences. Here, we provide a comprehensive review of type I and type III IFN activities, highlighting shared and distinct features from molecular mechanisms through physiological responses. Beyond discussing canonical antiviral functions, we consider the adaptive immune priming, anti-tumor, and autoimmune functions of IFNs. We discuss a model wherein type III IFNs serve as a front-line defense that controls infection at epithelial barriers while minimizing damaging inflammatory responses, reserving the more potent type I IFN response for when local responses are insufficient. In this context, we discuss current therapeutic applications targeting these cytokine pathways and highlight gaps in understanding of the biology of type I and type III IFNs in health and disease.

Interferon alpha treatment leads to a high rate of hepatitis B surface antigen seroconversion in Chinese children with chronic hepatitis B

Chronic hepatitis B virus (HBV) infection (CHB) in children remains a public health challenge despite significant success in programme is established to prevent mother-to-child transmission. In particular, CHB in Chinese children are mostly acquired through vertical transmission, which differs from the common infection route reported in other countries and regions. This situation has resulted in a high endemic prevalence of CHB in Chinese adults. Thus, successful treatment of children with CHB will prevent the development of advanced liver diseases in late adulthood. However, there is still no consensus on the clinical guideline to treat paediatric CHB. In this study, we evaluated the potential of interferon alpha (IFNa) treatment for Chinese children with CHB. A total of 41 patients with CHB aged 3-17 years were enrolled in this retrospective study: 21 patients were treated with pegylated (PEG)-IFNa and 20 patients without treatment served as the control group. The rates of HBV DNA suppression, hepatitis B e antigen (HBeAg) clearance and hepatitis B surface antigen (HBsAg) clearance were significantly higher in the PEG-IFNa treatment group than in the control group (P < 0.05 at 48 weeks). Unexpectedly, PEG-IFNa treatment achieved a high rate of HBsAb production, far exceeding the clinical outcome in documented PEG-IFNa-treated CHB adults. Further analysis revealed that younger children (3-6 years old) were more responsive to PEG-IFNa treatment with respect to achieving a protective level of HBsAb in a short treatment cycle than adolescents (10-17 years old). Overall, these results indicate that the immune system of children might have a preserved PEG-IFNa-mediated mechanism to completely control HBV, which can help to design new strategies to treat CHB patients.

Current state-of-the-art pharmacotherapy for the management of hepatitis B infection

INTRODUCTION

Hepatitis B virus (HBV) infection remains a global challenge with several hundred million infected individuals. Disease activity can be controlled, and adverse outcomes prevented when treatment can be provided. Frequently life-long therapy is required instead of defined treatment periods such as with the case of Hepatitis C Virus (HCV) infection.

AREAS COVERED

In this review, the authors provide an overview of current start of the art therapy for HBV and indicate where variation from the current guidelines could be considered. Certain patients may be eligible for treatment with suboptimal therapies when their baseline viral load is low. Identifying ideal candidates for interferon therapy will result in good sustained responses for some patients.

EXPERT OPINION

The biggest challenge remains linking patients to care and therapy. Patients can nowadays be sufficiently treated before the disease advances to a more progressed phase. However, future therapies must be extremely safe and ideally limit the required treatment period. Given Hepatitis D Virus's dependence on HBV and being a disease with an unmet clinical need, HDV may be the best target group for the development of a functional cure for hepatitis B.

Management of Hepatitis B Virus Infection: 2018 Guidelines from the Canadian Association for the Study of Liver Disease and Association of Medical Microbiology and Infectious Disease Canada

Hepatitis B virus (HBV) infection is an important public health problem in Canada. In keeping with evolving evidence and understanding of HBV pathogenesis, the Canadian Association for the Study of Liver Disease periodically publishes HBV management guidelines. The goals of the 2018 guidelines are to (1) highlight the public health impact of HBV infection in Canada and the need to improve diagnosis and linkage to care, (2) recommend current best-practice guidelines for treatment of HBV, (3) summarize the key HBV laboratory diagnostic tests, and (4) review evidence on HBV management in special patient populations and include more detail on management of HBV in pediatric populations. An overview of novel HBV tests and therapies for HBV in development is provided to highlight the recent advances in HBV clinical research. The aim and scope of these guidelines are to serve as an up-to-date, comprehensive resource for Canadian health care providers in the management of HBV infection.

Taiwan consensus statement on the management of chronic hepatitis B

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

Genotype Matters in Patients with Acute-on-chronic Liver Failure Due to Reactivation of Chronic Hepatitis B

Background

Acute-on-chronic liver failure (ACLF) can be caused by reactivation of chronic hepatitis B virus (HBV) infection (HBV-ACLF). It’s unclear whether HBV genotypes affect the clinical and therapeutical outcomes of patients with HBV-ACLF. This study was to investigate the short-term antiviral response and overall survival in HBV-ACLF patients treated by tenofovir or entecavir.

Methods

Seventy-three consecutive patients with HBV-ACLF were stratified into genotype B group (n = 33) and C group (n = 40). They were prospectively followed-up.

Results

At 2 weeks, the genotype B group had significantly lower HBV-DNA load (P = 0.005), greater HBV-DNA decline (P = 0.026), higher proportion of patients with HBV-DNA < 500 IU/ml (P = 0.007), improved Child-Turcotte-Pugh (CTP; P = 0.032) and model for end-stage liver disease (MELD; P = 0.039) scores compared to the genotype C group. At three months, survivors in both groups had undetectable HBV-DNA loads, comparable CTP (P = 0.850) and MELD (P = 0.861) scores; the genotype C group had markedly lower overall survival rate than the B group (P = 0.013). The genotype (hazard ratio [HR]: 2.138; 95% confidence interval [CI]: 1.034–4.143; P = 0.041), MELD score (HR:1.664, 95%CI: 1.077–2.571; P = 0.022) and HBV-DNA decline (HR: 0.225, 95% CI: 0.067–0.758; P = 0.016) at 2 weeks were significantly associated with mortality at 3 months. No severe adverse event was noted.

Conclusions

Genotype B was associated with better short-term antiviral response and clinical outcome compared to genotype C in patients with HBV-ACLF.

When Hepatitis B Virus Meets Interferons

Chronic hepatitis B virus (HBV) infection imposes a severe burden on global public health. Currently, there are no curative therapies for millions of chronic HBV-infected patients (Lok et al., 2017). Interferon (IFN; including pegylated IFN) is an approved anti-HBV drug that not only exerts direct antiviral activity, but also augments immunity against HBV infection. Through a systematic review of the literature, here we summarize and present recent progress in research regarding the interactions between IFN and HBV as well as dissect the antiviral mechanisms of IFN. We focus on inhibition of HBV replication by IFN-stimulated genes (ISGs) as well as inhibition of IFN signaling by HBV and viral proteins. Finally, we briefly discuss current IFN-based HBV treatment strategies. This review may help to better understand the mechanisms involved in the therapeutic action of IFN as well as the crosstalk between IFN and HBV, and facilitate the development of both direct-acting and immunology-based new HBV drugs.

Pegylated interferon-based sequential therapy for treatment of HBeAg reactive pediatric chronic hepatitis B-First study in children

BACKGROUND

Our aim was to evaluate the efficacy and safety of sequential therapy using pegylated interferon (Peg-IFN) and nucleos(t)ide analogue (NA) for treatment of children in immunoactive (IA) and immunotolerant (IT) phases of chronic hepatitis B.

METHODS

It was a prospective observational study where those willing for sequential therapy were allocated to group 1 (sequential therapy) and others to group 2 (standard therapy). Sequential therapy included 8 weeks of NA followed by 44 weeks of combination of NA and Peg-IFN. In group 2, IA children received NA monotherapy, and IT children received no therapy. HBe seroconversion, HBs seroconversion, and loss of HBV DNA were the major outcome measures.

RESULTS

A total of 61 children (36 IA and 25 IT) were included in the analysis. Among the IA children, 17 received sequential therapy and 19 received standard therapy; whereas, among the IT children, 12 received sequential therapy and 13 did not receive any therapy. In IA phase, sequential therapy led to higher HBe seroconversion (64.7% vs. 21.05%, p = 0.017) and higher virological clearance (94.12% vs. 52.63%, p = 0.008). In IT children, there was no benefit of treatment with sequential therapy over observation alone. Baseline ALT > 100 IU/L predicted response to therapy with 100% sensitivity, 89.5% specificity, and LR⁺ of 9.52.

CONCLUSION

Sequential therapy leads to higher HBe seroconversion and virological response in children in IA phase. Children with baseline ALT > 100 IU/mL are more likely to respond to sequential therapy. There appears to be no role of sequential therapy in children in IT phase.

Strategies for the treatment of HBV/HDV

An estimated 240 million people worldwide are chronically infected with the hepatitis B virus (HBV). Despite readily available vaccination, HBV infections remain highly prevalent. As established HBV infections constitute a strong risk factor for developing hepatocellular carcinoma their treatment is a major task for the health system. Unfortunately, HBV is not curable with today's medicine. Approximately 15 million HBV patients have developed a hepatitis delta (HDV) infection on top of their HBV infection. The patients superinfected with this satellite virus suffer from a more severe disease development. The knowledge of the viruses, their classifications, clinical implications, treatment options and efforts to increase the drug variety are compiled in this review. The current standard therapies include nucleosidic reverse transcriptase inhibitors and interferon. As the known treatments fail to cure HBV and HDV, targeted treatment is highly warranted. The focus of this review is set on the drugs currently under clinical investigation. Furthermore, strategies for the development of targeted treatment, and compounds with novel mode of action are described.

Renal Impairment in Chronic Hepatitis B: A Review

The liver plays a key role in the metabolism of proteins. Liver dysfunction affects many organs because it communicates with the spleen and all digestive organs through the portal vein. Additionally, the kidney is an organ that is closely related to the liver and is involved in liver diseases. Glomerulonephritis is an important extrahepatic manifestation of chronic hepatitis B virus (HBV) infection. Nucleos(t)ide analog (NA) therapy effectively suppresses HBV replication by inhibiting HBV polymerase, thus decreasing the levels of serum HBV-DNA and delaying the progression of cirrhosis. Although NA therapy is recommended for all patients with chronic HBV infection, regardless of the level of renal dysfunction, there is limited information on NA use in patients with chronic kidney disease. In addition, in patients with end-stage liver cirrhosis, hepatorenal syndrome can be fatal. Hence, we should take into account the stage of impaired renal function in patients with cirrhosis. The aims of this article are to review the epidemiology, clinical presentation, treatment, and prevention of HBV-associated nephropathy.

Sequential therapy involving an early switch from entecavir to pegylated interferon-α in Japanese patients with chronic hepatitis B

AIM

The optimal combination of two currently available agents with different mechanisms of action, a nucleos(t)ide analog and pegylated interferon-α (PegIFNα), must be determined to improve treatment of chronic hepatitis B (CHB).

METHODS

In this study, 24 patients with CHB (14 hepatitis B envelope antigen [HBeAg]-positive patients and 10 HBeAg-negative patients) received entecavir for 36-52 weeks, followed by entecavir plus Peg-IFNα2a for 4 weeks, and finally by PegIFNα-2a alone for 44 weeks.

RESULTS

A sustained biochemical, virologic, and serologic response was obtained in 7/24 (29%) patients at 48 weeks post-treatment (2/14 [14%] in HBeAg-positive vs 5/10 [50%] in HBeAg-negative patients, P = 0.085). At baseline, patients with a sustained response had a significantly lower γ-glutamyl transferase level (P = 0.0023), a lower aspartate aminotransferase-to-platelet ratio index (P = 0.049), and a lower α-fetoprotein level (P = 0.042) than those without a sustained response. The decline in hepatitis B surface antigen (HBsAg) levels during the first 24 weeks of PegIFNα-2a treatment in patients with a sustained response was greater than that in patients without (P = 0.017). Additionally, HBsAg seroclearance was achieved in two patients (8.3%): one HBeAg-positive and one HBeAg-negative patient.

CONCLUSION

The outcomes of sequential therapy involving an early switch from entecavir to PegIFNα-2a were unsatisfactory in Japanese patients with CHB. In addition to viral factors, host metabolic characteristics and liver fibrosis/tumor markers can be used for prediction of a sustained response to therapy, but accurate prediction of the therapeutic response is difficult.

Effects of antiviral therapy in patients with chronic hepatitis B and cirrhosis

Hepatitis B virus (HBV) infection is the major cause of cirrhosis worldwide. The ultimate goal of current antiviral treatments for chronic hepatitis B (nucleos(t)ide analogs and interferon-α) is to prevent the development of end-stage liver diseases. Areas covered: We present a review of the current literature on antiviral therapy in patients with chronic hepatitis B and cirrhosis. Medline search was performed to identify relevant literature from 1993 through January of 2017. Expert commentary: One randomized controlled trial and a number of observational studies have shown that nucleos(t)ide analogs can decrease the incidence of hepatocellular carcinoma (HCC) in chronic hepatitis B patients with advanced fibrosis. Data from clinical trials of entecavir and tenofovir have shown that histological improvement and regression of fibrosis can be achieved in the majority of patients with chronic hepatitis B by successful viral suppression. Entecavir and tenofovir are the preferred antiviral agents for treatment of chronic hepatitis B in patients with cirrhosis due to their high antiviral potency and high genetic barrier to resistance. Pegylated interferon-α is another therapeutic option for chronic hepatitis B patients with well-compensated cirrhosis. However, interferon therapy is contraindicated in patients with decompensated cirrhosis, and evidence for reduced HCC is currently insufficient.

Clinical Analysis of Polyethylene Glycol Interferon-α Treatment in 155 Hepatitis B e Antigen (HBeAg)-Positive Chronic Hepatitis B (CHB) Patients

PURPOSE

This study aims to investigate the antiviral effect of polyethylene glycol (PEG)-interferon α-2a and PEG-interferon α-2b treatment on hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) at the 48th week of treatment and the 24th and 48th week after withdrawal, in order to provide guidance on the antiviral treatment of HBeAg-positive CHB patients.

MATERIAL AND METHODS

Antiviral treatment was performed on 155 HBeAg-positive CHB patients. Among these patients, 66 patients received PEG-interferon α-2a treatment and 89 patients received PEG-interferon α-2b treatment; and these treatments were administered by subcutaneous injection, once per week, which lasted for 48 weeks. Other antiviral and hepatoprotective drugs were not used during the treatment.

RESULTS

At the 48th week of treatment, ALT recovery rate, HBsAg seroconversion rate, HBeAg seroconversion rate and HBV DNA titers dropped below 200 IU/mL rate were 69.7%, 6.1%, 27.3% and 50.0%, respectively, in the PEG-interferon α-2a group; and were 70.8%, 6.7%, 33.7% and 62.9%, respectively, in the PEG-interferon α-2b group. At the 24th and 48th week of follow-up after withdrawal, HBsAg seroconversion rate in these two groups did not change; and HBeAg seroconversion rate further increased. Furthermore, HBV DNA revealed a low recurrence rate. The difference between these two groups was not significantly significant.

CONCLUSIONS

PEG-interferon α-2a and PEG-interferon α-2b are effective antiviral drugs for the treatment of HbeAgpositive CHB, which has a HBsAg seroconversion rate of more than 5%. Furthermore, this sustained response effect was maintained at the 24th and 48th week of follow-up after withdrawal.

Addition of nucleoside analogues to peg-IFNα-2a enhances virological response in chronic hepatitis B patients without early response to peg-IFNα-2a: a randomized controlled trial

BACKGROUND

Current treatments for chronic hepatitis B (CHB) include pegylated interferon alpha (PEG-IFN-α) which is an immune modulator, and nucleos(t)ide analogs (NAs) which directly inhibit HBV DNA polymerase. With the limited efficacy of PEG-IFN-α and prolonged treatment periods associated with NAs, there is an urgent need for novel therapeutic strategies, especially for patients with a poor early response to anti-viral therapy.

METHODS

In this study, 178 patients with chronic hepatitis B (n = 131) and compensated (n = 47) HBV-induced cirrhosis were enrolled, 120 patients with HBeAg (+). All the patients were treated for 12 weeks with PEG-IFN-α. Among them, a total of 138 patients with a poor virological response after 12 weeks were treated for an additional 48 weeks with Peg-IFNα-2a (control) (n = 43), with Peg-IFNα-2a + entecavir (ETV) (n = 49), or Peg-IFNα-2a + adefovir dipivoxil (ADV) (n = 46), and were followed for 48 weeks after therapy. Early virological response was defined as undetectable HBV DNA after anti-viral therapy for 12 weeks. Sustained virological response (SVR) was defined as no change in therapeutic effectiveness after 6 months follow-up, and no recurrence.Therapeutic efficacy was determined by evaluating HBV DNA levels, serum and liver HBsAg levels, liver function tests and liver histology.

RESULTS

Patients in the Peg-IFNα-2a + ETV and Peg-IFNα-2a + ADV groups showed a significantly greater decrease in HBV DNA levels over time, and a significantly higher SVR compared to patients receiving Peg-INFα-2a monotherapy (both P values <0.05). Although patients receiving combination therapy had a significantly higher change in serum HBsAg levels compared to the monotherapy group, there was no significant difference in liver HBsAg levels between the three treatment groups.

CONCLUSION

This study demonstrated that in patients with a poor virological response after 12 weeks of treatment with Peg-IFNα-2a alone, addition of ADV or ETV significantly reduced HBV DNA levels, serum HBsAg levels, and increased SVR. Individualization of anti-viral therapy would ensure that only patients who do not respond to Peg-IFNα-2a would receive combination therapy. Our data have important implications for the treatment of CHB patients who fail to show an early response to Peg-IFNα-2a monotherapy.

TRIAL REGISTRATION

This trial was retrospectively registered on 2012 May 24 at the China Clinical Trials Registry (ChiCTR-OCC-12002196).

Immune balance in Hepatitis B Infection: Present and Future Therapies

Chronic hepatitis B virus (HBV) infection affects millions of people worldwide and about half a million people die every year. India represents the second largest pool of chronic HBV infections with an estimated 40 million chronically infected patients. Persistence or clearance of HBV infection mainly depends upon host immune responses. Chronically infected individuals remain in immune tolerant phase unless HBV flares and leads to the development of chronic active hepatitis or acute-on-chronic liver failure. Strategies based on inhibition of viral replication (nucleoside analogues) or immune modulation (interferons) as monotherapy, or in combination in sequential therapies, are currently being used globally for reducing HBV viral load and mediating HBsAg clearance. However, the immune status and current therapies for promoting sustained virological responses in HBV-infected patients remain suboptimal. Elimination of cccDNA is major challenge for future therapies, and new molecules such as NTCP, Toll-like receptor (TLR)7 agonist (GS9620) and cyclophilin have emerged as potential targets for preventing HBV entry and replication. Other than these, HBV cccDNA elimination is the major target for future therapies.

Hepatitis B Virus Immunopathology, Model Systems, and Current Therapies

Most people develop acute hepatitis B virus (HBV)-related hepatitis that is controlled by both humoral and cellular immune responses following acute infection. However, a number of individuals in HBV-endemic areas fail to resolve the infection and consequently become chronic carriers. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Standard treatment in HBV infection includes IFN-α, nucleoside, or nucleotide analogs, which has direct antiviral activity and immune modulatory capacities. However, immunological control of the virus is often not durable. A robust T-cell response is associated with control of HBV infection and liver damage; however, HBV-specific T cells are deleted, dysfunctional, or become exhausted in chronic hepatitis patients. As a result, efforts to restore virus-specific T-cell immunity in chronic HBV patients using antiviral therapy, immunomodulatory cytokines, or therapeutic vaccination have had little success. Adoptive cell transfer of T cells with specificity for HBV antigen⁺ cells represents an approach aiming to ultimately eliminate residual hepatocytes carrying HBV covalently closed circular DNA (cccDNA). Here, we discuss recent findings describing HBV immunopathology, model systems, and current therapies.

Alpha-interferon treatment in hepatitis B

Pegylated interferon-α (PEG-IFN-α) is a first line option in the treatment of chronic hepatitis B. Compared with nucleos(t)ide analogues (NAs), therapy with PEG-IFN-α has the advantages of finite treatment duration and higher rates of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) seroconversion, but the disadvantage of greater adverse effects. Choosing PEG-IFN-α requires careful evaluation of the likelihood of achieving a sustained off-treatment response. Sustained off-treatment response with PEG-IFN-α can be predicted by baseline factors in HBeAg positive disease. These include genotype A or B, low viral load, high alanine aminotransferase (ALT), older age and female gender. On the other hand, no pre-treatment factors have been identified that can reliably predict response in HBeAg negative disease. Using on-treatment quantitative HBsAg levels, failure of a long term response can be identified with high negative predictive value (NPV). However, no combination of on treatment parameters have been identified so far that can precisely forecast successful treatment. Up until recently, there was little evidence supporting the use of combining PEG-IFN with NAs. The addition of PEG-IFN in patients who already have viral suppression with NAs therapy appears superior to continuing NAs alone in achieving a sustained response. Also, tenofovir disoproxil fumarate (TDF) in combination with PEG-IFN has been reported to enable significantly higher HBsAg loss than with either monotherapy alone. This occurred in both HBeAg positive and negative patients across all genotypes. In spite of recent developments, rates of HBsAg loss are still only in the order of 10% and so cure remains elusive. Further research is required to identify the optimal combination or sequential therapy regimen, and the subgroups with the highest rates of response so that they can be targeted.

Pediatric hepatitis B treatment

Although the introduction of hepatitis B vaccine has been contributing to the reduction in the prevalence of hepatitis B virus (HBV) carriers worldwide, the treatment of children with chronic HBV infection is a challenge to be addressed. HBeAg seroconversion, which induces low replication of HBV, is widely accepted as the first goal of antiviral treatment in children with chronic hepatitis B. However, spontaneous HBeAg seroconversion is highly expected in children with chronic HBV infection. Therefore, the identification of children who need antiviral treatment to induce HBeAg seroconversion is essential in the management of chronic HBV infection. Guidelines and experts' opinion show how to identify children who should be treated and how to treat them. If decompensated cirrhosis is absent, interferon-alpha is the first-line antiviral treatment. Nucleos(t)ide analogues (NAs), such as lamivudine, adefovir, entecavir and tenofovir, are also available for the treatment of children, although the approval age differs among them. If decompensated cirrhosis is present, NAs are the first-line antivirals. When the emergence of drug-resistant HBV variants is taken into consideration, entecavir (approved for age 2 years or older) and tenofovir (age 12 years or older), which have high genetic barriers, will play a central role in the treatment of HBV infection. However, the optimal duration of NA treatment and adverse events of long-term NA treatment remain unclear in children. In resource-constrained countries and regions, the financial burden of visiting hospitals, receiving routine blood examination and purchasing antiviral drugs is heavy. Moreover, there is no clear evidence that the induction of HBeAg seroconversion by antiviral treatment prevents the progression of liver disease to cirrhosis and hepatocellular carcinoma in children with chronic HBV infection. It is thus imperative to clarify the clinical impact of antiviral treatment in children with HBV infection.

Inhibition of CRISPR/Cas9-Mediated Genome Engineering by a Type I Interferon-Induced Reduction in Guide RNA Expression

Clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-mediated genome engineering technology is a powerful tool for generation of cells and animals with engineered mutations in their genomes. In order to introduce the CRISPR/Cas9 system into target cells, nonviral and viral vectors are often used; however, such vectors trigger innate immune responses associated with production of type I interferons (IFNs). We have recently demonstrated that type I IFNs inhibit short-hairpin RNA-mediated gene silencing, which led us to hypothesize that type I IFNs may also inhibit CRISPR/Cas9-mediated genome mutagenesis. Here we investigated this hypothesis. A single-strand annealing assay using a reporter plasmid demonstrated that CRISPR/Cas9-mediated cleavage efficiencies of the target double-stranded DNA were significantly reduced by IFNα. A mismatch recognition nuclease-dependent genotyping assay also demonstrated that IFNα reduced insertion or deletion (indel) mutation levels by approximately half. Treatment with IFNα did not alter Cas9 protein expression levels, whereas the copy numbers of guide RNA (gRNA) were significantly reduced by IFNα stimulation. These results indicate that type I IFNs significantly reduce gRNA expression levels following introduction of the CRISPR/Cas9 system in the cells, leading to a reduction in the efficiencies of CRISPR/Cas9-mediated genome mutagenesis. Our findings provide important clues for the achievement of efficient genome engineering using the CRISPR/Cas9 system.

Type I Interferons Impede Short Hairpin RNA-Mediated RNAi via Inhibition of Dicer-Mediated Processing to Small Interfering RNA

RNAi by short hairpin RNA (shRNA) is a powerful tool not only for studying gene functions in various organisms, including mammals, but also for the treatment of severe disorders. However, shRNA-expressing vectors can induce type I interferon (IFN) expression by activation of innate immune responses, leading to off-target effects and unexpected side effects. Several strategies have been developed to prevent type I IFN induction. On the other hand, it has remained unclear whether type I IFNs have effects on shRNA-mediated RNAi. Here, we show that the type I IFNs significantly inhibit shRNA-mediated RNAi. Treatment with recombinant human IFN-α significantly inhibited shRNA-mediated knockdown of target genes, while it did not inhibit small interfering RNA (siRNA)-mediated knockdown. Following treatment with IFN-α, increased and decreased copy numbers of shRNA and its processed form, respectively, were found in the cells transfected with shRNA-expressing plasmids. Dicer protein levels were not altered by IFN-α. These results indicate that type I IFNs inhibit shRNA-mediated RNAi via inhibition of dicer-mediated processing of shRNA to siRNA. Our findings should provide important clues for efficient RNAi-mediated knockdown of target genes in both basic researches and clinical gene therapy.

Prediction model for sustained hepatitis B e antigen seroconversion to peginterferon alfa-2a in chronic hepatitis B

BACKGROUND AND AIM

Clinically applicable models to predict hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) response to peginterferon (PEG-IFN) are scarce. This study aimed to develop simple scoring systems, based on multiple parameters, for predicting sustained HBeAg seroconversion to PEG-IFN.

METHODS

Eighty-five treatment-naïve patients with HBeAg-positive CHB underwent 52-week PEG-IFN treatment and 24-week follow-up. Logistic regression analysis assessed parameters at baseline and weeks 12, 24, and 52 to predict HBeAg seroconversion at week 24 off-treatment. The best three predictors at each time point were included in prediction models of PEG-IFN therapy efficacy.

RESULTS

The three most meaningful predictors were alanine aminotransferase (ALT) > 5 × ULN, HBeAg ≤ 500 S/CO, and antibody to hepatitis B core antigen (anti-HBc) > 10.7 S/CO at baseline; HBeAg ≤ 20 S/CO, anti-HBc > 11.7 S/CO, and HBeAg decline > 1 log₁₀ S/CO at week 12; ALT > 2 × ULN, HBeAg ≤ 15 S/CO, and anti-HBc > 10.4 S/CO at week 24; HBeAg ≤ 5 S/CO, anti-HBc > 11.1 S/CO, and hepatitis B virus DNA decline > 2 log₁₀ copies/mL at week 52. Parameters meeting optimal cutoff thresholds were scored 1 or otherwise scored 0. For total scores of 0 versus 3 at baseline and weeks 12, 24, and 52, response rates were 6.3%, 12.5%, 0%, and 0% versus 90.0%, 83.3%, 76.9%, and 86.4%, respectively.

CONCLUSIONS

We successfully established prediction models for PEG-IFN response in HBeAg-positive CHB.

Interferon Treatment for Hepatitis B

Chronic hepatitis B virus (HBV) infection has a significant public health impact. There are currently 7 approved therapies for chronic HBV, including standard and pegylated interferon (IFN)-α, and 5 nucleos(t)ide analogs (NUCs). IFN offers benefits over NUCs, including a finite duration of therapy and a higher rate of clearance of hepatitis Be antigen and surface antigen. These benefits need to be weighed against the potential adverse effects of IFN therapy. Some patients should not receive IFN because of advanced liver disease or comorbidities. This article reviews the mechanisms of action, efficacy, and clinical use of IFN therapy for HBV infection.

HBsAg and HBeAg in the prediction of a clinical response to peginterferon α-2b therapy in Chinese HBeAg-positive patients

BACKGROUND

This study aimed to evaluate the predictive values of hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) levels in 171 Chinese patients with chronic hepatitis B who received a 48-week course of pegylated interferon alfa-2b therapy at 1.5 mcg/kg.

METHODS

HBsAg, HBeAg, and hepatitis B virus (HBV) DNA levels were measured at baseline and weeks 12, 24, 48, and 72. Clinical responses were defined as a combined response (CR, HBeAg seroconversion [sustained response, SR] combined with HBV DNA level <2,000 IU/mL at week 72). The positive predictive value and negative predictive value were calculated for HBsAg alone and/or combined with HBeAg and HBV DNA at weeks 12 and 24.

RESULTS

Of 171 patients included, 58 (33.9 %) achieved a SR. Of patients who achieved a SR, 33 (56.9 %) achieved a CR. Totally 19.3 % (33/171) patients achieved CR and 80.7 % (138/171) patients did not. Patients with HBsAg <1500 IU/mL at week 12 had a 47.4 % chance of achieving an off-treatment SR and patients with a HBsAg decrease >1.5 logIU/mL at week 12 had a 54.5 % chance. Patients with HBsAg >20,000 IU/mL at weeks 12 and 24 had a 93.8 and 100.0 % chance, respectively, of not achieving a CR. An HBsAg level or changes at weeks 12 and 24, combined with HBeAg or HBV DNA, increased the chance for a SR and CR.

CONCLUSIONS

On-treatment HBsAg quantification, alone or in combination with HBeAg or HBV DNA, predicted off-treatment SR and CR after 48 weeks of PEG-IFNα-2b therapy, and thus, may guide clinicians in making a therapeutic decision to continue or terminate the therapy.

Predictors of response to pegylated interferon in chronic hepatitis B: a real-world hospital-based analysis

Information on the efficacy of pegylated interferon (PEG-IFN) treatment of chronic hepatitis B (CHB) patients and predictors of the response based on real-world data is limited. Consecutive 201 patients who underwent PEG-IFN treatment for CHB were reviewed. A virological response (VR) was defined as a serum HBV DNA of <2000 IU/mL, and a combined response (CR) was defined a VR accompanied by serological response for hepatitis B e antigen (HBeAg)-positive CHB. For HBeAg-positive CHB patients, the HBeAg seroconversion rate and CR rate were 30.5% and 21.2% at 48 weeks after end of treatment (EOT), respectively. Baseline alanine aminotransferase (ALT) level was associated with HBeAg seroconversion, while baseline hepatitis B s antigen (HBsAg) levels of <250 IU/mL and HBV DNA <2.5 × 10⁷ IU/mL were strongly associated with sustained off-treatment CR. For HBeAg-negative CHB, the VR rates were 85.5%, and 27.7% at EOT, and 48 weeks after EOT, respectively; a baseline HBsAg <1,250 IU/mL was associated with sustained off-treatment VR. PEG-IFN treatment has durable HBeAg seroconversion in HBeAg-positive CHB, but results in a high risk of relapse among HBeAg-negative CHB patients. Pre-treatment HBsAg level is an important predictor of VR in CHB patients undergoing PEG-IFN treatment.