Kinetics of hepatitis B surface antigen loss in patients with HBeAg-positive chronic hepatitis B treated with tenofovir disoproxil fumarate

Long-Term Treatment With Tenofovir Alafenamide for Chronic Hepatitis B Results in High Rates of Viral Suppression and Favorable Renal and Bone Safety

INTRODUCTION

The results from 2 phase 3 studies, through 2 years, in chronic hepatitis B infection showed tenofovir alafenamide (TAF) had similar efficacy to tenofovir disoproxil fumarate (TDF) with superior renal and bone safety. We report updated results through 5 years.

METHODS

Patients with HBeAg-negative or HBeAg-positive chronic hepatitis B infection with or without compensated cirrhosis were randomized (2:1) to TAF 25 mg or TDF 300 mg once daily in double-blind (DB) fashion for up to 3 years, followed by open-label (OL) TAF up to 8 years. Efficacy (antiviral, biochemical, and serologic), resistance (deep sequencing of polymerase/reverse transcriptase and phenotyping), and safety, including renal and bone parameters, were evaluated by pooled analyses.

RESULTS

Of 1,298 randomized and treated patients, 866 receiving TAF (DB and OL) and 432 receiving TDF with rollover to OL TAF at year 2 (n = 180; TDF→TAF3y) or year 3 (n = 202; TDF→TAF2y) were included. Fifty (4%) TDF patients who discontinued during DB were excluded. At year 5, 85%, 83%, and 90% achieved HBV DNA <29 IU/mL (missing = failure) in the TAF, TDF→TAF3y, and TDF→TAF2y groups, respectively; no patient developed TAF or TDF resistance. Median estimated glomerular filtration rate (by using Cockcroft-Gault) declined <2.5 mL/min, and mean declines of <1% in hip and spine bone mineral density were seen at year 5 in the TAF group; patients in the TDF→TAF groups had improvements in these parameters at year 5 after switching to OL TAF.

DISCUSSION

Long-term TAF treatment resulted in high rates of viral suppression, no resistance, and favorable renal and bone safety.

Long-Term HBsAg Titer Kinetics with Entecavir/Tenofovir: Implications for Predicting Functional Cure and Low Levels

The long-term kinetics of quantitative HBsAg levels in HBV-infected patients treated with entecavir or tenofovir, as well as the role of quantitative HBsAg in predicting functional cure (HBsAg loss) and low HBsAg levels (<2 log IU/mL) remain unclear. Of some 1661 consecutively enrolled patients newly treated with entecavir or tenofovir, we analyzed 852 patients who underwent serial HBsAg level checks every 6-12 months. The primary outcomes included long-term kinetics in HBsAg levels and the rate of functional cure and achieving low HBsAg levels. Over a mean 6.3-year follow-up, the functional cure rate was 2.28% (n = 19), and 12.9% (n = 108) achieved low HBsAg levels. A significant HBsAg level reduction was seen in the first treatment year (p < 0.05), with another stepwise decrease between year 6-7. These trends were pronounced in patients with chronic hepatitis and HBeAg-positivity compared to those with cirrhosis and HBeAg-negativity, respectively. Baseline HBsAg of ≤3 log IU/mL and the first-year HBsAg reduction were key predictors for both functional cure and low HBsAg levels (p < 0.05). In conclusion, our findings elucidate the stepwise reduction in quantitative HBsAg dynamics during high-potency NA therapy (entecavir or tenofovir) along with variations based on different conditions. We also underscore the significance of quantitative HBsAg titer in predicting functional cure and low-HBsAg levels.

Rapid monophasic HBsAg decline during nucleic-acid polymer-based therapy predicts functional cure

BACKGROUND AND AIMS

Analyzing the interplay among serum HBV DNA, HBsAg, anti-HBs, and alanine aminotransferase (ALT) during nucleic-acid polymer (NAP)-based therapy for chronic hepatitis B provides a unique opportunity to identify kinetic patterns associated with functional cure.

METHODS

All participants with HBeAg-negative chronic HBV infection in the REP 401 study (NCT02565719) first received 24 weeks of tenofovir-disoproxil-fumarate (TDF) monotherapy. The early triple therapy group (n = 20) next received 48 weeks of TDF+pegylated interferon-α2a (pegIFN)+NAPs. In contrast, the delayed triple therapy group (n = 20) next received 24 weeks of TDF+pegIFN before 48 weeks of triple therapy. Three participants discontinued treatment and were excluded. Functional cure (HBsAg and HBV DNA not detectable with normal ALT) was assessed at 48 weeks post-treatment. Different kinetic phases were defined by at least a 2-fold change in slope. A single-phase decline was categorized as monophasic, and 2-phase declines were categorized as biphasic.

RESULTS

Fourteen (35%) participants achieved a functional cure. HBV DNA remained below or near undetectable for all participants by the end of TDF monotherapy and during subsequent combination therapies. Three HBsAg kinetic patterns were found in both the early and delayed groups, nonresponders (n = 4 and n = 4), monophasic (n = 11 and n = 11), and biphasic (n = 4 and n = 3), respectively. All participants who achieved a functional cure had a monophasic HBsAg kinetic pattern during triple therapy. Among participants with a monophasic HBsAg decline, those who had a functional cure had a shorter median time to HBsAg loss of 21 (interquartile range=11) weeks compared with those who did not achieve functional cure [median: 27 (7) weeks] (p = 0.012).

CONCLUSIONS

Functional cure was associated with a rapid monophasic HBsAg decline during NAP-based therapy. A nonmonophasic HBsAg kinetic pattern had a 100% negative predictive value (NPV) for a functional cure.

Predicting the loss of hepatitis B surface antigen following haematopoietic stem cell transplantation in patients with chronic HBV infection

Clearance of hepatitis B surface antigen (HBsAg) is an ideal therapeutic goal for patients with chronic hepatitis B virus (HBV) infection. Haematopoietic stem cell transplantation (HSCT) is the most effective therapy for a variety of haematological diseases. For patients with chronic HBV infection who received allo-HSCT, recipient hepatitis B serological status might change after allo-HSCT; however, data on the loss of HBsAg following allo-HSCT are relatively rare. We first reviewed patients with chronic HBV infection who received allo-HSCT in our centre from 2010 to 2020, and 125 patients were included in our study. A total of 62 patients (49.6%) with chronic HBV infection achieved HBsAg loss after allo-HSCT. Positivity for HBeAb and HBsAb in donors as well as no cytomegalovirus (CMV) infection were identified as independent risk factors for HBsAg loss after allo-HSCT. A predictive model including positivity for HBeAb and HBsAb in donors and no CMV infection was subsequently developed and performed well with effective discrimination and calibration. In addition, patients could benefit when this model is used in the clinic, as revealed via decision-curve analysis (DCA). However, multicentre prospective studies are required for validation.

Retreatment Efficacy and Renal Safety of Tenofovir Alafenamide, Entecavir, and Tenofovir Disoproxil Fumarate After Entecavir or Tenofovir Cessation

BACKGROUND

We aimed to compare the one-year retreatment efficacy and renal safety of entecavir, tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF) after HBV relapse in patients who discontinued entecavir or TDF.

METHODS

This retrospective study included 289 chronic hepatitis B (CHB) patients without cirrhosis who received entecavir (n = 93), TDF (n = 103), or TAF (n = 86) retreatment for at least 12 months after entecavir or TDF cessation.

RESULTS

The rate of virological response (HBV DNA < 20 IU/mL) at 12 months of retreatment was 79/93 (84.9%) in the entecavir group, 92/103 (89.3%) in the TDF group, and 72/86 (83.7%) in the TAF group. The rate of ALT normalization (ALT ≤ 40 U/L) after 12 months of retreatment was 76/93 (81.7%) in the entecavir group, 77/103 (74.7%) in the TDF group , and 73/86 (84.9%) in the TAF group. There was no significant difference in the rates of virological response (p = 0.495) and ALT normalization (p = 0.198) among the three groups. Multivariate analysis showed that lower HBV DNA and HBsAg levels at baseline were independently associated with virological response at 12 months of retreatment. The TDF group (37.8 ± 34.8 U/L) had higher ALT levels at 12 months of retreatment than the TAF (27. ± 17.9 U/L, p = 0.015) and entecavir (28.3 ± 19.3 U/L, p = 0.022) groups. In patients with eGFR 60-90 mL/min/1.73 m², eGFR change between baseline and 12 months of retreatment increased in the entecavir and TAF groups and decreased in the TDF group.

CONCLUSIONS

TAF could be one of the retreatment options for retreatment of HBV relapse after entecavir or TDF cessation.

Trend patterns of HBsAg kinetics in chronic hepatitis B patients during nucleos(t)ide analogue therapy based on ARMA models

BACKGROUND

Trend pattern analysis are lacking for hepatitis B surface antigen (HBsAg) kinetics in chronic hepatitis B (CHB) patients during nucleos(t)ide analogue (Nuc) therapy. We evaluated the trend patterns of HBsAg kinetics by time series analysis and forecasting times to HBsAg seroclearance accordingly.

METHODS

A total of 116 CHB patients with documented three-month HBsAg levels during the previous more than five years of Nuc therapy were included. The piecewise linear trends of the autoregressive-moving average (ARMA) model were used for time series analysis of HBsAg kinetics trends. Best fitted models were created for each patient using HBsAg datasets with backtracking capability. Predicted time to HBsAg seroclearance was calculated accordingly.

RESULTS

Four trend patterns of HBsAg kinetics were found: no trend (n = 22, 19.0%), single trend (n = 16, 13.8%), biphasic trend with rapid-slow decline (n = 56, 48.2%) and biphasic trend with rise-decline (n = 22, 19.0%). Except for no-trend patients, the trend became slow reduction as HBsAg declined. Only 6.1% of patients continued rapid decline when the initial HBsAg of the last trend reached <100 IU/mL. Last trend slopes < -10 and rise-decline patterns indicate greater chances of achieving HBsAg seroclearance within two years.

CONCLUSIONS

Best fitted ARMA models of HBsAg kinetics can be created individually for patients during Nuc therapy. About 67.2% patients have biphasic trend patterns, suggesting the dynamic nature of HBsAg kinetics over time. Trend patterns and last trend slopes predict individual times to HBsAg seroclearance.

Preclinical characterization of ABI-H2158, an HBV core inhibitor with dual mechanisms of action

The HBV core protein plays an integral role in multiple steps of the HBV lifecycle. Consequently, HBV core inhibitors interrupt multiple steps of the replication cycle, including blocking pgRNA encapsidation and prematurely disassembling existing nucleocapsids, thereby preventing them from transporting relaxed circular (rcDNA) to the nucleus for conversion to covalently closed circular DNA (cccDNA). ABI-H2158 is an HBV core inhibitor that advanced into Phase 2 clinical trials for the treatment of chronic hepatitis B virus infection (cHBV) but was discontinued due to hepatotoxicity. Here, the potency, selectivity, and mechanisms of action of ABI-H2158 were evaluated using a variety of cell-based assays. Antiviral activity was measured by quantifying intracellular or secreted HBV DNA, RNA, and antigens. ABI-H2158 inhibited HBV replication by blocking pgRNA encapsidation in induced HepAD38 cells (EC₅₀ = 22 nM) and had similar potency in HBV-infected HepG2-NTCP cells (EC₅₀ = 27 nM) and primary human hepatocytes (PHH) (EC₅₀ = 41 nM). ABI-H2158 is a pan-genotypic HBV inhibitor, with EC₅₀s ranging from 7.1 to 22 nM across HBV genotypes A-E. ABI-H2158 also potently blocked the formation of cccDNA in de novo HBV infections with EC₅₀s of ∼200 nM in HepG2-NTCP and PHH assays. These results indicate ABI-H2158 has dual mechanisms of action, inhibiting both early and late steps of the HBV replication cycle.

Molecular clones of genetically distinct hepatitis B virus genotypes reveal distinct host and drug treatment responses

Background & Aims

HBV exhibits wide genetic diversity with at least 9 genotypes (GTs), which differ in terms of prevalence, geographic distribution, natural history, disease progression, and treatment outcome. However, differences in HBV replicative capacity, gene expression, and infective capability across different GTs remain incompletely understood. Herein, we aimed to study these crucial aspects using newly constructed infectious clones covering the major HBV GTs.

Methods

The replicative capacity of infectious clones covering HBV GTs A-E was analyzed in cell lines, primary hepatocytes and humanized mice. Host responses and histopathology induced by the different HBV GTs were characterized in hydrodynamically injected mice. Differences in treatment responses to entecavir and various HBV capsid inhibitors were also quantified across the different genetically defined GTs.

Results

Patient-derived HBV infectious clones replicated robustly both in vitro and in vivo. GTs A and D induce more pronounced intrahepatic and proinflammatory cytokine responses which correlated with faster viral clearance. Notably, all 5 HBV clones robustly produced viral particles following transfection into HepG2 cells, and these particles were infectious in HepG2-NTCP cells, primary human hepatocytes and human chimeric mice. Notably, GT D virus exhibited higher infectivity than GTs A, B, C and E in vitro, although it was comparable to GT A and B in the human liver chimeric mice in vivo. HBV capsid inhibitors were more readily capable of suppressing HBV GTs A, B, D and E than C.

Conclusions

The infectious clones described here have broad utility as genetic tools that can mechanistically dissect intergenotypic differences in antiviral immunity and pathogenesis and aid in HBV drug development and screening.

Lay summary

The hepatitis B virus (HBV) is a major contributor to human morbidity and mortality. HBV can be categorized into a number of genotypes, based on their specific genetic make-up, of which 9 are well known. We isolated and cloned the genomes of 5 of these genotypes and used them to create valuable tools for future research on this clinically important virus.

Secreted hepatitis B virus splice variants differ by HBV genotype and across phases of chronic hepatitis B infection

Chronic hepatitis B (CHB) is characterized by progression through different phases of hepatitis B virus (HBV) infection and disease. Although not necessary for HBV replication, there is increasing evidence that HBV splice variants are associated with liver disease progression and pathogenesis. However, there have been no studies till date on the frequency or diversity of splice variants for different HBV genotypes across the phases of CHB. Next generation sequencing data from 404 patient samples of HBV genotype A, B, C or D in Phase I, Phase II or Phase IV of CHB was analysed for HBV splice variants using an in house bioinformatics pipeline. HBV splice variants differed in frequency and type by genotype and phase of natural history. Splice variant Sp1 was the most frequently detected (206/404, 51% of patients), followed by Sp13 (151/404 37% of patients). The frequency of variants was generally highest in Phase II (123/165, 75% of patients), a phase typically associated with enhanced immune activation, followed by Phase I (69/99, 70% of patients). Splice variants were associated with reduced hepatitis B e antigen (HBeAg) levels and statistically reduced likelihood of achieving HBsAg loss (functional cure) in Phase II patients for Sp1 and Sp13 (p = .0014 and .0156, respectively). The frequency of HBV splice variants in patient serum differed markedly by HBV genotype and phase of CHB natural history. The increased levels of HBV splice variants detected in CHB phase II patients compared with the higher replicative Phase I in particular warrants further investigation.

Virological Treatment Monitoring for Chronic Hepatitis B

More than 250 million people worldwide are currently infected with hepatitis B, despite the effectiveness of vaccination and other preventive measures. In terms of treatment, new therapeutic approaches are rapidly developing, promising to achieve the elimination of infected cells and the complete cure of infection. The on-treatment monitoring of these innovative antiviral treatments will require the implementation of new virological tools. Therefore, new biomarkers are being evaluated besides the traditional virological and serological assays in order to obtain information on different steps of the viral replication cycle and to monitor response to therapy more accurately. The purpose of this work is to describe both standard and innovative tools for chronic hepatitis B treatment monitoring, and to analyse their potential and feasibility.

HBsAg Loss as a Treatment Endpoint for Chronic HBV Infection: HBV Cure

Despite the availability of effective vaccines and antiviral therapy over the past two to three decades, chronic hepatitis B virus (HBV) infection remains a major global health threat as a leading cause of cirrhosis and liver cancer. Functional HBV cure defined as hepatitis B surface antigen (HBsAg) loss and undetectable serum HBV DNA is associated with improved clinical outcomes in patients with chronic HBV infection. However, spontaneous loss of HBsAg is rare and occurs in only 1% of all HBsAg-positive individuals annually. Furthermore, the rate of functional cure with currently available antiviral therapy is even lower, <1% patients on treatment per year. Nonetheless, HBsAg loss has become the new target or therapeutic endpoint for antiviral treatment. Recently, there has been much excitement surrounding the development of novel antiviral agents such as small interfering RNA (siRNA), core assembly modulators (CAMs), nucleic acid polymers (NAPs) among others, which may be used in combination with nucleos(t)ide analogs and possibly immunomodulatory therapies to achieve functional cure in a significant proportion of patients with chronic hepatitis B. Novel assays with improved sensitivity for detection of very low levels of HBsAg and to determine the source of HBsAg production will also be required to measure efficacy of newer antiviral treatments for HBV cure. In this narrative review, we will define HBV cure, discuss various sources of HBsAg production, evaluate rates of HBsAg loss with current and future antiviral agents, review clinical factors associated with spontaneous HBsAg loss, and explore clinical implications of functional cure.

Evaluation of Tenofovir Disoproxil Fumarate Treatment in Patients with Chronic Hepatitis B

Objective

The main purpose of chronic hepatitis B (CHB) treatment is to improve the patients' life quality and prevent the disease from progressing to cirrhosis or hepatocellular carcinoma. Continuous suppression of hepatitis B virus (HBV) DNA with nucleoside or nucleotide analogues is the most critical way to achieve this goal. This study aimed to evaluate the CHB patients retrospectively followed up with tenofovir disoproxil fumarate (TDF) treatment.

Materials and Methods

The study was planned as retrospective research by Afyonkarahisar Health Sciences University, Faculty of Medicine, Department of Infectious Diseases and Clinical Microbiology between January 2001 and December 2020. We evaluated all treatment-naive and treatment-experienced patients who received TDF (245 mg/day) treatment with the diagnosis of CHB. The data were obtained by reviewing the file information registered in the hospital automation system. HBsAg, Anti-HBs, HBeAg, Anti-HBe, HBV DNA, aspartate aminotransferase (AST), alanine aminotransferase (ALT) values of the patients were evaluated at 1st, 3rd, 6th, 12th months, and 6-month follow-ups throughout the treatment. Virological (HBV-DNA of < 50 IU/ml), biochemical (decrease below 40 IU/Ml in patients with pre-treatment value of ALT >40 IU/ml) and serological (Anti-HBe seroconversion in HBeAg positives and HBsAg negative and anti-HBs seroconversion in all patients) responses were examined. Adverse effects were also assessed during the treatment.

Results

Data from 131 patients who received TDF treatment were evaluated. Virological responses were determined as 78.6%, 81.3%, 94.2%, and 100% in the patients at 24th week, 48th week, 4th year, and 8th year, respectively. While there was no Anti-HBs seroconversion in any patients in four years of the treatment, it was observed at a rate of 10.5% in the eighth year. We did not determine any significant adverse effects requiring discontinuation of the treatment in the long-term follow-up of 131 patients under TDF treatment.

Conclusion

As a result of our study, TDF was an effective and well-tolerated choice for CHB treatment.

Kinetics of hepatitis B surface antigen in pregnant women with and without tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent mother-to-infant transmission in highly viremic HBV-infected women. Data on hepatitis B surface antigen (HBsAg) levels in pregnant women are lacking. We aimed to investigate prepartum and postpartum HBsAg kinetics and its correlation with HBV DNA in pregnant women. HBV-infected mothers with HBV DNA ≥7.5 log₁₀  IU/ml were tested for HBsAg and HBV DNA from baseline to 6 months postpartum. Of the 186 pregnant women with comparable baseline HBsAg and HBV DNA, 101 received TDF from the third trimester until 1 month postpartum. At delivery, TDF group had mildly lower HBsAg (4.32 ± 0.47 vs. 4.54 ± 0.35 log₁₀  IU/ml, p = .0004) and markedly lower HBV DNA (4.26 ± 0.97 vs. 8.11 ± 0.70 log₁₀  IU/ml, p < .0001) than the control group. In the TDF group, mean reduction of HBsAg and HBV DNA from baseline to delivery were 0.22 ± 0.38 and 3.96 ± 0.93 log₁₀  IU/ml. HBsAg reduction had a positive correlation (r = .309; p = .0017) with HBV DNA reduction, and was predictive of HBV DNA reduction ≥3 log₁₀  IU/ml (area under the receiver operating characteristic curve, 0.67; 95% confidence interval, 0.50-0.82). At 6 months postpartum, TDF and control group had comparable HBsAg and HBV DNA. In conclusion, HBsAg decreased slightly at delivery in pregnant women receiving TDF. For monitoring the effect of antiviral therapy during pregnancy, HBV DNA is a better marker than HBsAg. Our data provided valuable information regarding monitoring HBV-infected pregnant women using antiviral therapy.

Hepatitis B virus genotype is an independent prognostic factor of telbivudine and tenofovir treatment in hepatitis B surface antigen-positive pregnant women

To investigate whether HBV genotype influences the effect of tenofovir and telbivudine on HBV DNA and RNA levels in HBsAg-positive pregnant women. This was a retrospective study of 74 HBsAg-positive pregnant women in Guizhou of China. All patients were treated with telbivudine or tenofovir from 12 weeks of pregnancy and HBV infection to the date of delivery. Blood samples were collected at 12-24, 28-32, and 36-40 weeks of pregnancy for the measurement of genotype, HBsAg, hepatitis B e antigen (HBeAg), HBV DNA, HBV RNA, and liver function, including alanine transaminase, aspartate transaminase, total bilirubin, total bile acids, cholinesterase, alkaline phosphatase (ALP), and gamma-glutamyl transferase. All women with HBsAg were followed up. The HBV genotype was B in 64.9% and C in 35.1%. There were 37 patients of telbivudine and tenofovir group respectively. The telbivudine and tenofovir groups showed no differences in demographic and clinical characteristics, including liver function tests, HBsAg, HBeAg, log10(HBV DNA), and log10(HBV RNA). Compared with baseline (12-24 weeks), telbivudine group showed a significant increase in ALP and significant reductions in HBsAg, HBeAg, log10(HBV DNA), and log10(HBV RNA) at 36-40 weeks (p < .05). Tenofovir group exhibited a significant increase in ALP and significant reductions in HBeAg, log10(HBV DNA), and log10(HBV RNA) at 36-40 weeks, compared with baseline (p < .05). HBV genotype (B vs. C) was independently associated with HBV DNA change after therapy (p = .005). In telbivudine group, log10 (HBV DNA) increased from 3.38 (2.00-7.30) to 7.43 (4.68-8.70). In tenofovir group, log10 (HBV DNA) decreased from 7.52 (3.32-8.70) to 2.98 (2.00-5.01). HBV genotype was independently associated with HBV DNA change response to telbivudine or tenofovir in pregnant women with hepatitis B. These findings might be helpful for risk assessment regarding vertical transmission of HBV in HBeAg-positive mothers treated with nucleos(t)ide analogues.

How to interpret viral markers in the management of chronic hepatitis B infection

BACKGROUND

Hepatitis B virus (HBV) infection is a global public health issue with several unsolved clinical challenges. As multiple new drugs are under development, HBV markers are gaining importance for both diagnostic and prognostic purposes.

OBJECTIVES

This review summarizes the most important data on the usefulness of HBV markers in the natural history of this infection, and in predicting clinical and treatment outcomes.

SOURCES

Selected peer-reviewed publications on HBV markers published between January 2009 and July 2021.

CONTENT

In addition to the classical markers (e.g. HBV-DNA), newer ones, such as quantitative HBsAg, HBcrAg, HBV-RNA and quantitative anti-HBc, have proven useful for predicting events within the natural history of HBV infection, the development of complications (e.g. hepatocellular carcinoma) and the response to antiviral therapy. Most data regarding the response to treatment have been related to nucleos(t)ide analogues, whereas evidence on new therapeutic agents, such as capsid assembly modulators or small interference RNAs, is promising, but still scarce.

IMPLICATIONS

Knowledge on the use of viral markers is a key factor for optimizing the clinical appraisal of HBV infection. The new markers have an enhanced ability to predict clinical outcomes. Further studies should expand the current evidence on the use of markers in relation to antiviral agents currently under evaluation. Wide availability of these markers in regions with a high incidence of HBV infection is of paramount importance.

Treatment of Chronic Hepatitis B Virus with Oral Anti-Viral Therapy

Nucleoside analogues are the drugs most commonly used in the treatment of chronic hepatitis B. They act by inhibiting viral replication and have minimal impact on HBsAg loss. Nucleoside analogues are indicated in patients with chronic hepatitis, cirrhosis, decompensated cirrhosis, hepatocellular carcinoma, and in those with extrahepatic manifestations. Real-world experience has been ongoing for more than 10 years, and the efficacy and safety results obtained are similar to those reported in clinical trials. Prolonged use is needed to maintain suppression of viral replication, prevent the development of liver cirrhosis and decompensated cirrhosis, and to decrease the risk of hepatocellular carcinoma.

Controversies in Treating Chronic Hepatitis B virus: The Role of Hepatitis B Virus DNA and Surface Antigen Titer

Controversial areas in chronic hepatitis B (CHB) are those where there is uncertainty, or differences of opinion in management, or where evidence may be insufficient. Areas of controversy include whether patients with high viral load but normal liver function tests should be treated to prevent hepatocellular carcinoma (HCC) or liver disease progression to cirrhosis. Another area is whether quantitative hepatitis B surface antigen (qHBsAg) can be used to better characterize phases of CHB and prognosticate. Finally, the utility of qHBsAg in the management of patients on antiviral therapy such as interferon and nucleoside analogues could improve management practices.

Mean HBsAg decline at week 24 of PEG-IFN-based treatment predicts subsequent rate of HBsAg clearance - suggesting a valuable endpoint for early development HBV trials

Earlier identification of potentially efficacious treatments in early development trials requires on-treatment response markers. We hypothesized that mean week 12 or 24 HBsAg decline could be a useful marker for subsequent off-treatment sustained HBsAg clearance at the treatment arm level in HBV trials. We used individual patient data from the studies HBV 9901 (peginterferon [PEG-IFN] versus PEG-IFN+lamivudine for HBeAg-positive CHB), PARC (PEG-IFN±ribavirin for HBeAg-negative CHB) and published data from 0149 (PEG-IFN±tenofovir for HBeAg-positive and HBeAg-negative CHB) and LIRA-B (PEG-IFN for HBeAg-positive CHB) to define the relationship between mean week HBsAg decline and HBsAg loss at 6 months post-treatment. A within-study comparison of HBsAg decline at weeks 12 and 24 between patients with or without HBsAg clearance was used to make projections beyond the observed HBsAg data. Across trials, a more pronounced mean HBsAg decline at week 24 was associated with higher rates of subsequent HBsAg loss. Mean HBsAg decline data at week 24 for patients with or without HBsAg clearance from HBV 9901 (4.3 vs 0.5), PARC (4.8 vs 0.3) and 0149 (PEG-IFN+TDF arm; 4.6 vs 0.6) were used to extrapolate this relationship beyond observed rates of HBsAg. An additional mean 1 log₁₀ decline at week 24 versus a comparator arm is expected to translate into a 20%-30% increase in subsequent HBsAg loss during off-treatment follow-up. Observations were similar for week 12 data, but the relationship was less strong. Mean week 24 HBsAg decline predicts subsequent HBsAg loss and could be a valuable and useful early endpoint in HBV-treatment trials.

Efficacy and safety of tenofovir alafenamide fumarate in nucleoside analogue treatment-naïve patients with chronic hepatitis B

Tenofovir alafenamide fumarate (TAF) is a first-line drug for the antiviral treatment of patients with chronic hepatitis B (CHB) in China. In the present study, the efficacy and renal safety of TAF were evaluated in treatment-naive patients with CHB. Patients with CHB who had not been previously treated with nucleoside analogues (NAs) were recruited before TAF treatment was initiated. Changes in the levels of hepatitis B virus (HBV) DNA, hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) were analyzed at 24 and 48 weeks using immunoassays. In addition, liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) were analyzed using transient elastography, while alanine aminotransferase (ALT), triglyceride (TG), total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels, calcium (Ca) and inorganic phosphorus (IP) levels were measured using biochemistry assay. In addition, the estimated glomerular filtration rate (eGFR) was calculated. After 48 weeks, the ALT normalization rate was 95.24% (40/42), the complete virological response (HBV DNA <20 IU/ml) rate was 69.05% (29/42) and the HBeAg seroconversion rate was 8.57% (3/35). The levels of HBV DNA and HBsAg were significantly decreased from the baseline at 5.49±1.95 to 1.26±0.66 log₁₀ IU/ml and from 3.59±0.81 to 3.32±0.55 log₁₀ IU/ml after 48 weeks of treatment, respectively. Compared with that in the baseline measurements, LSM at 48 weeks was significantly decreased from 13.00±8.15 to 8.66±4.45 kPa. No significant differences were observed in the TG, TC, LDL-C, CAP, eGFR, Ca and IP measurements. According to the baseline ALT levels, patients were divided into group A [ALT ≤1 x upper limit of normal (ULN); ULN=50 U/l; n=21], group B (1 x ULN < ALT <2 x ULN; n=22) and group C (ALT ≥2 x ULN; n=18). A significant decrease in HBsAg levels was observed in group B (3.63±0.68 vs. 3.53±0.63 log₁₀ IU/ml) and group C (4.15±0.57 vs. 3.66±0.48 log₁₀ IU/ml) at 24 weeks compared with the baseline. In conclusion, TAF was found to be effective and safe in NA treatment-naive patients with CHB. Moreover, the higher the ALT levels, the more prominent the curative effect from TAF treatment. Therefore, NA treatment-naive CHB patients could benefit from TAF treatment in real world.

Challenges and opportunities for hepatitis B cure in the setting of HIV--hepatitis B virus co-infection

PURPOSE OF REVIEW

To examine issues specific to HIV--HBV co-infection that are relevant to the search for and achieving hepatitis B cure in this the setting RECENT FINDINGS: In HIV--HBV co-infection, high rates of hepatitis B surface antigen (HBsAg) loss early after initiation of HBV-active antiretroviral therapy (ART) have previously been reported. Between 2012 and 2016, HBsAg loss from 2.8 to 23% was reported in numerous studies, including those already on suppressive HBV-active ART. Data published in 2018-2019 show that these rates have remained fairly stable (3.0-13.9%). However, it appears that higher HBsAg loss on starting HBV-active ART in co-infection falls within a few years to levels similar to that observed in long-term treated HBV mono-infection. Immune reconstitution and CD4+ T-cell recovery are likely to play a role in high HBsAg loss rates seen in early treated co-infection, although the mechanisms driving this are yet to be fully elucidated.

SUMMARY

High rates of HBsAg loss early after HBV-active ART initiation is unique to HIV--HBV co-infection, making it the ideal setting to investigate underlying mechanisms of HBV loss and develop new HBV cure strategies. This phenomenon could be used to enhance HBsAg loss with new therapeutic approaches currently being investigated; however, this is obstructed by excluding co-infection from such studies.

Usefulness of a Hepatitis B Surface Antigen-Based Model for the Prediction of Functional Cure in Patients with Chronic Hepatitis B Virus Infection Treated with Nucleos(t)ide Analogues: A Real-World Study

In patients with chronic hepatitis B (CHB) under long-term treatment with nucleso(t)ide analogues (NAs), the loss of hepatitis B surface antigen (HBsAg) is a rare event. A growing body of evidence supports the use of quantitative HBsAg for the prediction of functional cure, although these results are mainly derived from studies performed on Asian patients with hepatitis B e antigen (HBeAg)-positive CHB. Here, we investigated the clinical role of quantitative HBsAg in a real-life cohort of CHB patients under treatment with NAs in a tertiary care center from North-West Italy. A total of 101 CHB patients (HBeAg-negative, n = 86) undergoing NAs treatment were retrospectively enrolled. HBsAg was measured at baseline (T0), 6 months (T1), 12 months (T2) and at the last follow-up (FU). Median FU was 5.5 (3.2–8.3) years; at the end of FU, 11 patients lost the HBsAg (annual incidence rate = 1.8%). Baseline HBsAg levels were significantly different between patients with no HBsAg loss and those achieving a functional cure (3.46, 2.91–3.97 vs. 1.11, 0.45–1.98 Log IU/mL, p < 0.001). Similarly, the HBsAg decline (Δ) from T0 to T2 was significantly different between the two groups of patients (0.05, −0.04–0.13, vs. 0.38, 0.11–0.80 Log IU/mL, p = 0.002). By stratified cross-validation analysis, the combination of baseline HBsAg and ΔHBsAg T0–T2 showed an excellent accuracy for the prediction of HBsAg loss (C statistic = 0.966). These results corroborate the usefulness of quantitative HBsAg in Caucasian CHB patients treated with antivirals for the prediction of HBsAg seroclearance.

3-year Treatment of Tenofovir Alafenamide vs. Tenofovir Disoproxil Fumarate for Chronic HBV Infection in China

BACKGROUND AND AIMS

Tenofovir alafenamide (TAF) has similar efficacy to tenofovir disoproxil fumarate (TDF) but with improved renal and bone safety in chronic hepatitis B patients studied outside of China. We report 3-year results from two phase 3 studies with TAF in China (Clinicaltrials.gov: NCT02836249 and NCT02836236).

METHODS

Chinese hepatitis B e antigen (HBeAg)-positive and -negative chronic hepatitis B patients with viremia and elevated alanine aminotransferase were randomized 2:1 to TAF or TDF treatment groups and treated in a double-blind fashion for 144 weeks (3 years). Efficacy responses were assessed by individual study while safety was assessed by a pooled analysis.

RESULTS

Of the 334 patients (180 HBeAg-positive and 154 HBeAg-negative) randomized and treated, baseline characteristics were similar between groups. The overall mean age was 38 years and 73% were male. The mean HBV DNA was 6.4 log₁₀ IU/mL. The median alanine aminotransferase was 88 U/L, and 37% had a history of antiviral use. At week 144, the proportion with HBV DNA <29 IU/mL was similar among the two groups, with TAF at 83% vs. TDF at 79%, and TAF at 93% vs. TDF at 92% for the HBeAg-positive and -negative patients, respectively. In each study, higher proportions of TAF than TDF patients showed normalized alanine aminotransferase (via the American Association for the Study of Liver Diseases and the China criteria) and showed loss of HBsAg; meanwhile, the HBeAg seroconversion rates were similar. Treatment was well-tolerated among the TAF patients, who showed a smaller median decline in creatinine clearance (-0.4 vs. -3.2 mL/min; p=0.014) and less percentage change in bone mineral density vs. TDF at hip (-0.95% vs. -1.93%) and spine (+0.35% vs. -1.40%).

CONCLUSIONS

In chronic hepatitis B patients from China, TAF treatment provided efficacy similar to TDF but with better renal and bone safety at 3 years.

Long-Term TDF-Inclusive ART and Progressive Rates of HBsAg Loss in HIV-HBV Coinfection-Lessons for Functional HBV Cure?

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is effective in suppressing HIV and hepatitis B virus (HBV) replication in HIV-HBV coinfection although HBV DNA can persist in some individuals on TDF-containing antiretroviral therapy (ART). We initiated a prospective longitudinal study to determine durability of HBV virological control and clinical outcomes after prolonged TDF-based ART in HIV-HBV coinfection.

METHODS

Ninety-two HIV-HBV coinfected participants on, or about to commence, TDF-containing ART from Australia (n = 41) and Thailand (n = 52) were enrolled. Participants were followed 6-monthly for 2 years, then annually to 5 years. Laboratory and clinical assessments and a serum sample were collected at each study visit. These analyses compare follow-up at 2 and 5 years.

RESULTS

12.0% (95% confidence interval 6.8 to 20.2) of total study entry cohort (n = 92) or 15.3% (95% confidence interval: 8.8 to 25.3) of those with data to year 5 (n = 72) lost hepatitis B surface antigen (HBsAg). The only statistically significant association with HBsAg loss was lower study entry quantitative HBsAg. CD4 T-cell count increased by a median 245 cells/mm3 between the preTDF sample and 5 years of follow-up. By year 5, 98.5% of the cohort had undetectable HBV DNA (<15 IU/mL) and 91.4% had undetectable HIV RNA (<20 copies/mL).

CONCLUSIONS

HBsAg loss was high and ongoing over 5 years of follow-up in HIV-HBV coinfected individuals on TDF-containing ART and undetectable HBV was almost universal. Although the pattern of HBsAg loss temporarily parallels immune reconstitution, we could not identify predictive immune markers. The high rate of HBsAg loss in HIV-HBV coinfection may offer valuable insights into the search for a functional HBV cure.

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

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

Comparative biomarkers for HBsAg loss with antiviral therapy shows dominant influence of quantitative HBsAg (qHBsAg)

BACKGROUND

Biomarkers such as quantitative HBsAg (qHBsAg), quantitative hepatitis B virus (HBV) core-related antigen (qHBcrAg) and HBV RNA may be useful in predicting HBsAg loss in patients with chronic hepatitis B (CHB) undergoing antiviral therapy.

AIM(S)

Our study evaluated qHBsAg, HBV RNA and qHBcrAg as a posthoc analysis of a randomized clinical trial of peginterferon±NA to determine their utility in predicting HBsAg loss.

METHODS

CHB patients who completed therapy with 48weeks peginterferon alpha2b ± nucleoside analogue therapy (clinicaltrial.gov NCT01928511) were evaluated at week 72 for HBsAg loss. The predictive ability of qHBsAg, qHBcrAg, HBV RNA and other variables were investigated by univariate and multivariate logistic models for HBeAg-negative patients by odds ratios, area under the curve (AUC), sensitivity, specificity, and positive and negative likelihood ratios (LR).

RESULTS

HBsAg loss occurred in 15/114(13%) HBeAg-negative CHB patients who completed 48 weeks of peginterferon. At baseline, qHBsAg was superior to HBcrAg and HBV RNA with AUC 0.916, 0.649 and 0.542, respectively. Using multivariate analysis, the model comprising treatmentarm, age, gender, baseline qHBsAg, HBcrAg and HBV RNA, weeks 4 & 8 qHBsAg had the highest AUC(0.98), but the univariate model with week 8 qHBsAg <70 IU/mL had AUC 0.96. Hence, the contributions of variables other than qHBsAg were marginal. HBV RNA and qHBcrAg were weak predictors of HBsAg loss. Kinetics of the novel markers showed only qHBsAg had a good relationship with HBsAg loss while HBV RNA had a marginal relationship and HBcrAg did not change at all, and none had a good relationship with viral rebound.

CONCLUSIONS

On-treatment biomarker predictors were better than baseline ones, and the best predictor of HBsAg loss at 72 weeks was week 8 qHBsAg <70 IU/mL.

Hepatitis B surface antigen and hepatitis B core-related antigen kinetics after adding pegylated-interferon to nucleos(t)ids analogues in hepatitis B e antigen-negative patients

BACKGROUND

Hepatitis B e antigen-negative chronic hepatitis B patients under nucleos(t)ids analogues (NAs) rarely achieve hepatitis B surface antigen (HBsAg) loss.

AIM

To evaluate if the addition of pegylated interferon (Peg-IFN) could decrease HBsAg and hepatitis B core-related antigen (HBcrAg) levels and increase HBsAg loss rate in patients under NAs therapy.

METHODS

Prospective, non-randomized, open-label trial evaluating the combination of Peg-IFN 180 µg/week plus NAs during forty-eight weeks vs NAs in monotherapy. Hepatitis B e antigen-negative non-cirrhotic chronic hepatitis B patients of a tertiary hospital, under NAs therapy for at least 2 years and with undetectable viral load, were eligible. Patients with hepatitis C virus, hepatitis D virus or human immunodeficiency virus co-infection and liver transplanted patients were excluded. HBsAg and HBcrAg levels (log10 U/mL) were measured at baseline and during ninety-six weeks. HBsAg loss rate was evaluated in both groups. Adverse events were recorded in both groups. The kinetic of HBsAg for each treatment group was evaluated from baseline to weeks 24 and 48 by the slope of the HBsAg decline (log10 IU/mL/week) using a linear regression model.

RESULTS

Sixty-five patients were enrolled, 61% receiving tenofovir and 33% entecavir. Thirty-six (55%) were included in Peg-IFN-NA group and 29 (44%) in NA group. After matching by age and treatment duration, baseline HBsAg levels were comparable between groups (3.1 vs 3.2) (P = 0.25). HBsAg levels at weeks 24, 48 and 96 declined in Peg-IFN-NA group (-0.26, -0.40 and -0.44) and remained stable in NA group (-0.10, -0.10 and -0.10) (P < 0.05). The slope of HBsAg decline in Peg-IFN-NA group (-0.02) was higher than in NA group (-0.00) (P = 0.015). HBcrAg levels did not change. Eight (22%) patients discontinued Peg-IFN due to adverse events. The HBsAg loss was achieved in 3 (8.3%) patients of the Peg-IFN-NA group and 0 (0%) of the NA group.

CONCLUSION

The addition of Peg-IFN to NAs caused a greater and faster decrease of HBsAg levels compared to NA therapy. Side effects of Peg-IFN can limit its use in clinical practice.

The evolution and clinical impact of hepatitis B virus genome diversity

The global burden of hepatitis B virus (HBV) is enormous, with 257 million persons chronically infected, resulting in more than 880,000 deaths per year worldwide. HBV exists as nine different genotypes, which differ in disease progression, natural history and response to therapy. HBV is an ancient virus, with the latest reports greatly expanding the host range of the Hepadnaviridae (to include fish and reptiles) and casting new light on the origins and evolution of this viral family. Although there is an effective preventive vaccine, there is no cure for chronic hepatitis B, largely owing to the persistence of a viral minichromosome that is not targeted by current therapies. HBV persistence is also facilitated through aberrant host immune responses, possibly due to the diverse intra-host viral populations that can respond to host-mounted and therapeutic selection pressures. This Review summarizes current knowledge on the influence of HBV diversity on disease progression and treatment response and the potential effect on new HBV therapies in the pipeline. The mechanisms by which HBV diversity can occur both within the individual host and at a population level are also discussed.

Kinetics of hepatitis B surface antigen and estimated glomerular filtration rate in telbivudine-treated hepatitis B patients with different rescue strategies

This study investigated the kinetics of estimated glomerular filtration rate (eGFR) and quantitative hepatitis B surface antigen (qHBsAg) in telbivudine (LdT)-treated chronic hepatitis B (CHB) patients whose treatment was subsequently adjusted with the adding on adefovir or by switching to tenofovir disoproxil fumarate (TDF) as rescue. Of 295 CHB patients initially treated with LdT, 102 of them who subsequently receiving either adding-on adefovir (group A, n = 58) or switching to TDF (group B, n = 44) for more than 24 months were enrolled. Serial eGFR and qHBsAg levels (3 to 6 monthly) in both LdT monotherapy and rescue therapy periods were analyzed retrospectively. Subsequent decline of qHBsAg especially in rescue therapy period were noted (p<0.001 and p = 0.068 in group A and B). However, patients in group B achieved a significant increase of eGFR (p = 0.010) in LdT monotherapy period but had a significant decline of eGFR (p<0.001) in rescue therapy period. In contrast, patients in group A maintained eGFR levels in both periods. Meanwhile, switch to TDF (hazard ratio: 3.036; 95% confidence interval: 1.040-8.861; p = 0.042) was the sole factor related to the decrease of eGFR>20% from baseline. Both rescue therapies achieved subsequent declines of qHBsAg over time but caused different changes in eGFR. LdT-based rescue therapy maintained eGFR but TDF switching therapy descended eGFR. Therefore, it is essential to monitor patient's renal function intensively when switching from LdT to TDF as a rescue strategy.

Hepatitis B surface antigen seroclearance: Immune mechanisms, clinical impact, importance for drug development

HBsAg seroclearance occurs rarely in the natural history of chronic hepatitis B (CHB) infection and is associated with improved clinical outcomes. Many factors are associated with HBsAg seroconversion, including immune and viral factors. However, the immune mechanisms associated with HBsAg seroclearance are still difficult to elucidate. HBsAg seroclearance is the ideal aim of HBV treatment. Unfortunately, this goal is rarely achieved with current treatments. Understanding the mechanisms of HBsAg loss appears to be important for the development of curative HBV treatments. While studies from animal models give insights into the potential immune mechanisms and interactions occurring between the immune system and HBsAg, they do not recapitulate all features of CHB in humans and are subject to variability due to their complexity. In this article, we review recent studies on these immune factors, focusing on their influence on CHB progression and HBsAg seroconversion. These data provide new insights for the development of therapeutic approaches to partially restore the anti-HBV immune response. Targeting HBsAg will ideally relieve the immunosuppressive effects on the immune system and help to restore anti-HBV immune responses.

Quantative HBsAg level correlates dendritic cells maturation in chronic hepatitis B patients

BACKGROUND

In order to better understand the role of Dendritic cells (DCs) in Chronic Hepatitis B (CHB), we investigated the frequencies and maturation markers on DCs in CHB patients and its change during entecavir treatment.

METHODS

Twenty-six CHB patients on anti-virus treatment for 48 weeks were included in this study. Patients' blood samples were collected on every 3 months since starting treatment. Samples on baseline and after 48 weeks treatment were examined using flow-cytometry to investigate frequencies and maturation markers of DCs.

RESULTS

The frequencies of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) were lower in CHB patients than healthy controls on baseline. pDCs frequencies and mDCs maturation markers expression were increased after entecavir (ETV) treatment. Patients with higher baseline HBsAg levels showed a poorer maturation status than those with low baseline HBsAg levels, regardless of changes in HBsAg levels after treatment.

CONCLUSIONS

Entecavir treatment could restore the decreased DCs frequencies in CHB patients and improve DCs maturation levels. Baseline HBsAg level is an important factor that affecting DCs.

Incidence of hepatitis B virus infection among human immunodeficiency virus-infected treatment naïve adults in Botswana

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection is highest in sub-Saharan Africa and results in accelerated clinical outcomes compared with HBV or HIV mono-infection. HBV clearance rates are higher in healthy adults; however, in sub-Saharan Africa, there are limited data on clearance of incident HBV in HIV-infected adults. Therefore, we sought to estimate HBV incidence and HBV surface antigen (HBsAg) clearance in HIV-infected adults in Botswana.This was a retrospective longitudinal study of 442 HIV-1C infected treatment naïve patients enrolled in a previous Botswana Harvard AIDS Institute Partnership study. Archived plasma samples from 435 HIV-infected treatment naïve participants were screened for HBsAg and HBV core antibody (anti-HBc). HBsAg was evaluated annually over a 4-year period, and HBV deoxyribonucleic acid (DNA) levels of HBsAg-positive chronic and incident patients were quantified.Baseline median CD4+ T-cell count was 458 cells/μL [Q1, Q3: 373, 593], and median HIV viral load was 4.15 copies/mL [Q1, Q3: 3.46, 4.64]. Twenty two HBV incident cases occurred, representing an incidence of 3.6/100 person-years [95% CI: 2.2-5.6]. All incident HBV cases with a follow-up sample available for screening (13/22) cleared HBsAg. Detectable HBV viral loads among chronic and incident cases ranged between 5.15 × 10 to 1.4 × 10 IU/L and 1.80 × 10 to 1.7 × 10 IU/mL, respectively.We report high HBV incidence associated with elevated HBV DNA levels despite high CD4+ T-cell counts in HIV-infected patients in Botswana. These incidence cases represent a potential source of HBV transmission in the population. Scaling-up of HIV treatment strategies utilizing antiretroviral therapy regimens with anti-HBV activity coupled with screening for HBV infections in households of the HBsAg-positive cases is recommended.

Optimal management of chronic hepatitis B patients receiving nucleos(t)ide analogues

Management of chronic hepatitis B (CHB) is still considered a challenge in clinical practice. Patients must be carefully evaluated before starting therapy. This includes virology and laboratory assessments, an estimation of fibrosis by invasive and/or noninvasive methods, and an estimation of the risk of hepatocellular carcinoma (HCC). Nucleos(t)ide analogues (NAs) with a high barrier to resistance (tenofovir disoproxil fumarate [TDF], entecavir [ETV] and tenofovir alafenamide [TAF]) are the most frequently used treatments because of their good long-term efficacy and tolerability. None of these options has been shown to be more effective than the other, but certain factors should be considered when selecting the best therapy for specific populations. Most patients achieve a virological and biochemical response to these agents, with a low rate of emerging resistance during long-term treatment. However, the rate of hepatitis B surface antigen (HBsAg) loss is low and in most cases NAs therapy is lifelong. Safety concerns for long-term NA use have become a priority in the management of CHB, in particular, the risk of impaired kidney function and bone marrow density loss described with TDF regimens. The risk of HCC is not completely eliminated by NAs. Thus, patients at higher risk should be identified and provided with appropriate surveillance.

Dynamics of HBV surface antigen related end points in chronic hepatitis B infection: a systematic review and meta-analysis

BACKGROUND

In chronic hepatitis B (CHB) treatment, hepatitis B surface antigen (HBsAg) is regarded as a promising clinical end point associated with long-term clinical outcomes. We performed a meta-analysis to characterize the dynamics and influencing factors of HBsAg.

METHODS

Literature search was conducted through PubMed from January 1995 to May 2015 for papers reporting HBsAg in patients receiving various antiviral treatments. We conducted weighted linear regression to select for potential influencing factors on maximum HBsAg loss percentage, and subgroup analysis to calculate the pooled estimates of maximum HBsAg loss and seroconversion percentage following treatment of interferon (IFN), nucleoside analogue (NUC) or combination therapies (NUC+IFN), respectively. Study heterogeneity was assessed through sensitivity test and I-square statistics.

RESULTS

We collected data from 24 papers involving 6,674 adult CHB patients. In most studies, average HBsAg level decreased during treatment but relapsed after treatment cessation, while HBsAg loss or seroconversion percentage continued to increase or remained stable after treatment cessation. No strong relationship was observed between maximum HBsAg change and its baseline level. The pooled estimates of maximum HBsAg loss percentage for IFN (5.3%, 2.7-7.9%) and NUC+IFN (5.2%, 3.1-7.4%) were significantly higher than that of NUC (0.93%, 0.29-1.6%). Higher maximum HBsAg loss percentage is associated with longer peak time. Pooled maximum HBsAg seroconversion percentage estimates were 1.6%, 0.56% and 6.2% for IFN, NUC and NUC+IFN.

CONCLUSIONS

With respect to HBsAg lowering, this meta-analysis confirmed the importance of longer treatment duration and addition of IFN, which revealed the potential value of immune-based therapies.

Predicting HBsAg clearance in genotype A chronic hepatitis B using HBsAg epitope profiling: A biomarker for functional cure

BACKGROUND AND AIM

Functional cure is the major goal of chronic hepatitis B (CHB) therapy though few biomarkers predict this outcome. HBsAg epitope occupancy can be influenced by therapeutic and immune pressure. The aim of this study was to map the HBsAg epitope profiles during long-term nucleos(t)ide analogue therapy in patients with genotype A CHB, in the context of HBsAg loss (SL)/seroconversion.

METHODS

We evaluated 25 genotype A CHB patients in the GS-US-174-0103 trial of HBeAg-positive CHB patients treated with tenofovir or adefovir for 4 years, 14 who achieved SL whilst 11 had no change. We epitope mapped the major domains of HBsAg to identify those patients with HBsAg clearance profile (CP) (loss of binding at both loops 1 and 2 epitopes of the 'a' determinant) vs non-clearance profile (no change in epitope recognition, or loss of epitope binding at one loop only), correlating this to on-treatment HBsAg responses. Complexed anti-HBs was also measured.

RESULTS

Analysis of the HBsAg epitope profiles of the 25 patients at baseline identified no predictive correlation with SL. In contrast, analysis at week 48 and end of study (week 192) or prior to SL identified significant predictive associations between development of HBsAg CPs and outcome of functional cure. The detection of a CP also correlated with the development of an alanine aminotransferase flare and detection of anti-HBs complexed with HBsAg.

CONCLUSION

The detection of HBsAg CPs by epitope mapping represents a novel viral biomarker, reflecting an emerging anti-HBs selection pressure prior to functional cure.

Drugs in the Pipeline for HBV

Chronic hepatitis B remains a significant cause of morbidity and mortality worldwide. Most hepatitis B virus (HBV)-infected individuals are neither diagnosed nor treated. In those treated, nucleos(t)ide polymerase inhibitors persistently suppress viremia to the limits of quantitation; however, few achieve a "functional cure," defined as sustained off-treatment loss of detectable serum HBV DNA with or without loss of hepatitis B surface antigen. The low cure rate has been attributed to an inability to eliminate the viral reservoir of covalently closed circular DNA from hepatocytes. This review focuses on the diverse therapeutic approaches currently under development that may contribute to the goal of HBV cure.

Baseline HBsAg levels associated with HBsAg loss in HBeAg-negative chronic hepatitis B infection with persistently normal alanine aminotransferase

BACKGROUND

We aimed to assess the long-term outcomes of e antigen-negative chronic hepatitis B (CHB) infection with low hepatitis B virus (HBV) DNA level (< 200 IU/mL) and persistently normal alanine aminotransferase (PNALT) and to explore the factors associated with the results.

METHODS

This retrospective cohort study enrolled consecutive baseline CHB patients with PNALT from January 2005 to June 2008. In total, 252 e antigen-negative CHB patients with PNALT and low HBV DNA level (< 200 IU/mL) were enrolled, of whom 188 were eligible for this analysis. Among the 188 patients, 131 were followed up more than twice per year and 57 were followed up at least once per year, with a median follow-up period of 102 (73-123) months.

RESULTS

Of 188 patients, 16 had HBV DNA level of > 200 IU/mL and PNALT, 164 had HBV DNA level of < 200 IU/mL and PNALT and 8 had HBV DNA level of > 200 IU/mL and elevated ALT level, of which 3 used an antiviral drug during follow-up. Twelve of 164 experienced HBsAg loss. Cox regression analysis suggested that baseline HBsAg levels were associated with HBsAg loss in patients after follow-up, especially the baseline HBsAg levels of < 200 IU⁄mL, which is a risk factor for HBsAg loss. The AUC of baseline HbsAg level in the e antigen-negative CHB group was 0.772 (cutoff value 426, P < 0.001). The cumulative probability of HBsAg loss in the HBsAg < 400 IU/L group was 20% (7/35), which ws higher than that in the HBsAg ≥ 400 IU/L group (3.88%; 5/129; X2 = 11.75, P = 0.0006).

CONCLUSION

The e antigen-negative CHB infection with low HBV DNA level (< 200 IU/mL) and PNALT will progress to chronic hepatitis, although the probability of its occurrence is low. Spontaneous HBsAg loss may not occur frequently because the manifested cumulative probability of HBsAg loss was higher in the HBsAg < 400 IU/L group than in the HBsAg ≥ 400 IU/L group.

Long-term efficacy and safety of tenofovir disoproxil fumarate in Chinese patients with chronic hepatitis B: 5-year results

Background and aim

Long-term treatment with tenofovir disoproxil fumarate (TDF) has demonstrated suppression of viral replication outside of China. This study aims to assess efficacy, resistance and safety of TDF for up to 240 weeks in Chinese patients with chronic hepatitis B virus (HBV) infection.

Methods

Patients (HBeAg-positive or HBeAg-negative) who were randomised to receive TDF 300 mg or adefovir dipivoxil (ADV) 10 mg once daily in the 48-week double-blind phase (N = 498) were eligible to enter the open-label TDF phase (TDF–TDF and ADV–TDF groups) for additional 192 weeks.

Results

Overall, 457/512 (89.3%) randomised patients completed 240 weeks of treatment. Virological suppression was achieved in 84.5% and 87.9% in HBeAg-positive patients and 89.6% and 89.5% in HBeAg-negative patients in TDF–TDF and ADV–TDF groups, respectively, at week 240. The majority of patients from both groups had normalized alanine transaminase levels. More patients had HBeAg loss (41.7% vs. 36.4%) and HBeAg seroconversion (32.0% vs. 28.3%) in TDF–TDF than in ADV–TDF group, respectively. Only one HBeAg-positive patient in TDF–TDF group had HBsAg loss at week 240. No evidence of resistance to TDF was observed. The incidence of adverse events was similar in both groups (TDF–TDF, 56.4% vs. ADV–TDF, 51.6%). One patient had serum creatinine elevation ≥ 0.5 mg/dL above baseline, and three patients had confirmed grade 3/4 phosphorus abnormalities (< 2 mg/dL).

Conclusion

In Chinese patients with chronic HBV, long-term treatment with TDF showed sustained viral suppression without development of resistance up to 240 weeks. No new safety concerns were found with TDF in this patient population.

Clinical Trial Registration ClinicalTrial.gov Identifier NCT01300234; GSK Clinical Study Register 114648.

Electronic supplementary material

The online version of this article (10.1007/s12072-019-09943-6) contains supplementary material, which is available to authorized users.

New and Old Biomarkers for Diagnosis and Management of Chronic Hepatitis B Virus Infection

Tests to detect the presence and activity of hepatitis B virus (HBV) are the cornerstones of diagnosis and management. Assays that detect or measure serum levels of HB surface antigen, HB surface antibody, and HB core antibody are used to identify patients with exposure to HBV, whereas other tests provide information on the level of virus replication, presence of specific variants, and presence of virus reservoirs. Newer diagnostic tests, used only in research settings so far, aim to quantify levels of intrahepatic HBV replication. Other tests have been developed to detect HBV infection in resource-limited settings. We review point-of-care tests (essential in global screening efforts), standard diagnostic tests used in routine clinical management, and newer tests that might be used in clinical trials of agents designed to cure HBV infection.

Progression and status of antiviral monitoring in patients with chronic hepatitis B: From HBsAg to HBV RNA

As alternative indexes of hepatitis B virus (HBV), covalently closed circular DNA (cccDNA) transcriptional activity, hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg), and peripheral blood RNA known as pgRNA, have been advocated as novel serum markers for prediction of prognosis and treatment response in chronic hepatitis B (CHB). Since the availability of commercial quantitative assays of HBsAg in 2011, HBsAg has been widely used for predicting treatment response of patients with CHB. Patients who received interferon therapy have shown a sharper reduction of HBsAg level than those who received nucleoside drug (NAs) therapy. Upon peginterferon treatment, sustained responders have presented a larger reduction of HBsAg level than the non-responders. An absence of HBsAg decline, together with < 2log reduction in HBV DNA at week 12, can serve as a stopping rule in HBsAg-negative patients infected with genotype D HBV. A sharp reduction of HBsAg titer in the NAs therapy is a predictor of HBsAg clearance in long-term treatment. HBcrAg, which consists of three species of related proteins sharing an identical 149 amino acid sequence, including HbcAg, hepatitis B e antigen (HBeAg), and a truncated 22-kDa precore protein, is still detectable in situations where serum HBV DNA levels become undetectable or HBsAg loss is achieved. Therefore, HBcrAg remains a measurable serum marker to correlate with cccDNA in this situation. The decline in HBcrAg has been observed with NAs therapy and the pattern of decline might provide prognostic information on the risk of HBV post-treatment reactivation. Peripheral blood RNA, which is known as pgRNA, directly derives from cccDNA and reflects intrahepatic cccDNA level. Quantitative pgRNA has been suggested to be helpful in CHB management. However, commercial quantitative assays are lacking. Additionally, the use of simultaneous and continuous clearance of HBV RNA and HBV DNA in serum has been suggested to be a safe stopping rule of NAs therapy for patients with CHB. However, clinical studies of large sample sizes are needed to prove the feasibility and significance of using serum HBV RNA as the assessment standard of antiviral therapy in CHB and the safety of the stopping rule in clinics.

Varying 10-year off-treatment responses to nucleos(t)ide analogues in patients with chronic hepatitis B according to their pretreatment hepatitis B e antigen status

OBJECTIVE

To evaluate the long-term durability and efficacy of nucleos(t)ide analogues (NAs) and to determine the related factors for virological relapse in chronic hepatitis B (CHB) patients.

METHODS

CHB patients who fulfilled the criteria for discontinuing NAs therapy in accordance with the published guidelines were included in the study from December 2001. Virological relapse was defined as serum hepatitis virus B (HBV) DNA >10⁴ copies/mL twice at least 2 weeks apart.

RESULTS

A total of 223 CHB patients were enrolled at the time their NAs therapy was discontinued. The 10-year cumulative relapse rate (CRR) in hepatitis B e antigen (HBeAg)-positive patients was statistically lower than that in HBeAg-negative patients (30.9% vs 62.3%, P < 0.001). In the HBeAg-positive group, Cox regression analysis showed that age at cessation (hazard ratio [HR] 1.067, P < 0.001), consolidation therapy (HR 0.958, P = 0.021), and time to HBeAg seroconversion (HR 0.943, P = 0.019) were predictors for relapse. In the HBeAg-negative group, age at cessation (HR 1.040, P = 0.004) and time to HBV DNA negativity (HR 1.246, P = 0.010) were potential predictors for virological relapse.

CONCLUSIONS

The off-treatment responses to NAs differ in CHB patients with different pretreatment HBeAg status. NA withdrawal is generally safe and feasible in young patients with CHB. Long consolidation periods should be preferred in HBeAg-positive patients to achieve better durability. Benefits of cessation of NAs do not last long in HBeAg-negative CHB patients.

Serum hepatitis B surface antigen correlates with fibrosis and necroinflammation: A multicentre perspective in China

The kinetics of serum hepatitis B surface antigen (HBsAg) during the natural history of hepatitis B virus (HBV) infection has been studied, but the factors affecting them remain unclear. We aimed to investigate the factors affecting HBsAg titres, using data from multicentre, large-sized clinical trials in China. The baseline data of 1795 patients in 3 multicentre trials were studied, and the patients were classified into 3 groups: hepatitis B early antigen (HBeAg)-positive chronic HBV infection (n = 588), HBeAg-positive chronic hepatitis B (n = 596), and HBeAg-negative chronic hepatitis B (n = 611). HBsAg titres in the different phases were compared, and multiple linear progression analyses were performed to investigate the implicated factors. HBsAg titres varied significantly in different phases (P = .000), with the highest (4.60 log10 IU/mL [10%-90% confidence interval: 3.52 log10 IU/mL-4.99 log10 IU/mL]) in patients with HBeAg-positive chronic HBV infection. In all phases, age and HBV DNA were correlated with serum HBsAg level. In HBeAg-positive chronic hepatitis B patients, a negative correlation between HBsAg titres and fibrosis stage was observed. Alanine amonitransferase or necroinflammatory activity was also correlated with HBsAg titres in HBeAg-negative chronic hepatitis B patients. In conclusion, decreased HBsAg titres may be associated with advancing fibrosis in HBeAg-positive chronic hepatitis B patients or increased necroinflammation in those with HBeAg-negative chronic hepatitis B. Our findings may help clinicians better understand the kinetics of HBsAg and provide useful insights into the management of this disease.

Higher baseline viral diversity correlates with lower HBsAg decline following PEGylated interferon-alpha therapy in patients with HBeAg-positive chronic hepatitis B

Background

Viral diversity seems to predict treatment outcomes in certain viral infections. The aim of this study was to evaluate the association between baseline intra-patient viral diversity and hepatitis B surface antigen (HBsAg) decline following PEGylated interferon-alpha (Peg-IFN-α) therapy.

Patients and methods

Twenty-six HBeAg-positive patients who were treated with Peg-IFN-α were enrolled. Nested polymerase chain reaction (PCR), cloning, and sequencing of the hepatitis B virus S gene were performed on baseline samples, and normalized Shannon entropy (Sn) was calculated as a measure of small hepatitis B surface protein (SHBs) diversity. Multiple regression analysis was used to estimate the association between baseline Sn and HBsAg decline.

Results

Of the 26 patients enrolled in the study, 65.4% were male and 61.5% were infected with hepatitis B virus genotype B. The median HBsAg level at baseline was 4.5 log₁₀ IU/mL (interquartile range: 4.1–4.9) and declined to 3.0 log₁₀ IU/mL (interquartile range: 1.7–3.9) after 48 weeks of Peg-IFN-α treatment. In models adjusted for baseline alanine aminotransferase (ALT) and HBsAg, the adjusted coefficients (95% CI) for ΔHBsAg and relative percentage HBsAg decrease were −1.3 (−2.5, −0.2) log₁₀ IU/mL for higher SHBs diversity (Sn≥0.58) patients and −26.4% (−50.2%, −2.5%) for lower diversity (Sn<0.58) patients. Further analysis showed that the “a” determinant upstream flanking region and the first loop of the “a” determinant (nucleotides 341–359, 371–389, and 381–399) were the main sources of higher SHBs diversity.

Conclusion

Baseline intra-patient SHBs diversity was inverse to HBsAg decline in HBeAg-positive chronic hepatitis B (CHB) patients receiving Peg-IFN-α monotherapy. Also, more sequence variations within the “a” determinant upstream flanking region and the first loop of the “a” determinant were the main sources of the higher SHBs diversity.

Case report: lactic acidosis and rhabdomyolysis during telbivudine and tenofovir treatment for chronic hepatitis B

Background

Current treatment options for chronic hepatitis B (CHB) are pegylated interferon alpha and nucleoside analogues (NAs). NAs have relatively fewer side effects than interferon alpha, and generally well tolerated. Previously 12.9% of patients on telbivudine treatment were reported to develop severe elevation of serum creatine phosphokinase (CPK) levels, but related clinical disease, like lactic acidosis (LA) and rhabdomyolysis (RM) were rare. The pathophysiology may be mitochondrial toxicity, for the NAs inhibit not only hepatitis B virus (HBV) polymerase, but also the host mitochondrial DNA polymerase γ. As mitochondria are the main sites of oxidative phosphorylation, there will be an increase of pyruvate reduction to lactic acid and insufficient adenosine triphosphate. The accumulation of lactic acid causes LA, while lack of energy leads to cell dysfunction and mitochondria-associated disease, including RM. All five NAs, except tenofovir, have been reported causing LA and RM. Here we report the first case of CHB patients developing fatal LA and RM during telbivudine and tenofovir treatment.

Case presentation

The patient is a 51-year-old man who was hospitalized in November 2015. He had taken telbivudine regularly because of CHB. Later, tenofovir was added to antiviral treatment because of HBV resistance. Then he had myalgia, chest tightness and anorexia. The blood lactate was 12.7 mmol/L. The arterial blood gas analysis showed pH 7.25, base excess 21.1 mmol/L. CPK was 991 U/L, myoglobin was 1745 ng/ml and creatine was 83 μmol/L. Abdomen magnetic resonance revealed cirrhosis. Muscle biopsy revealed myogenic lesion with abnormality of mitochondria and fat metabolism. The patient was diagnosed with Hepatitis B envelope Antigen positive CHB, cirrhosis, LA and RM characterized by myalgia and elevated myoglobin. He was given tenofovir alone as antiviral treatment instead. After hemodialysis and 4 weeks` treatment of corticosteroids, his symptoms recovered, and blood lactate gradually returned to a normal range.

Conclusions

This case shows that tenofovir may trigger muscle damage and fatal RM in combination with telbivudine treatment in CHB patients. Thus, patients receiving tenofovir and telbivudine should be closely monitored for muscular abnormalities, blood lactate level and other mitochondrial toxicity associated side effects.

Trajectories of serum hepatitis B surface antigen kinetics in patients with chronic hepatitis B receiving long-term nucleos(t)ide analogue therapy

BACKGROUND & AIMS

The kinetics of serum hepatitis B surface antigen (HBsAg) levels during long-term nucleos(t)ide analogue (NA) therapy in chronic hepatitis B (CHB) patients remains unclear. We investigated the patterns of serum HBsAg kinetics and their association with therapeutic outcomes in genotype B- or C-infected CHB patients receiving long-term NA therapy.

METHODS

We enrolled 329 treatment-naive CHB patients receiving NA therapy for >5 years to analyse the kinetic patterns by using group-based trajectory models (GBTMs).

RESULTS

Most patients (82.4%) received entecavir therapy. The median treatment duration was 83.6 (68.5-89.7) months. The GBTMs revealed three groups for both the hepatitis B e antigen (HBeAg)-positive and -negative patients. The median annual decline in serum HBsAg levels during the first 5 years was significantly higher in Group 1 than in Groups 2 and 3 in HBeAg-positive (0.78 vs 0.10 vs 0.10 log₁₀ IU/mL) and HBeAg-negative (0.71 vs 0.08 vs 0.09 log₁₀ IU/mL) patients. HBsAg levels at the baseline and 12 months combined with an HBsAg decline from the baseline to 12 months of treatment predicted trajectory pattern 1 in HBeAg-positive (sensitivity, 77.8%; specificity, 99.1%; positive predictive value [PPV], 87.5%; and negative predictive value [NPV], 98.2%) and HBeAg-negative (sensitivity, 100%; specificity, 99.5%; PPV, 88.9%; and NPV, 100%) patients. The trajectory patterns were significantly associated with HBeAg loss in the HBeAg-positive patients and the achievement of HBsAg <100 IU/mL or HBsAg loss in HBeAg-positive and HBeAg-negative patients.

CONCLUSIONS

The trajectory of serum HBsAg levels predicts HBsAg loss in CHB patients receiving long-term NA therapy.

Great and rapid HBsAg decline in patients with on-treatment hepatitis flare in early phase of potent antiviral therapy

HBsAg decline during nucleos(t)ide analogue therapy in chronic hepatitis B with lower pretherapy ALT is usually small and slow. This study aimed to investigate why ~10% of such patients showed "rapid HBsAg decline" ≥0.5 log₁₀ IU/mL by month 6 of therapy. Patients with persistent pretherapy ALT <5X ULN who had qHBsAg at baseline, months 6 and 12 of entecavir or tenofovir therapy were studied. "On-treatment ALT elevation" was defined as >10% increase above baseline to >2X ULN during first 6 months of therapy. Of the 256 patients treated, 51 experienced transient "on-treatment ALT elevation" [group A], including 30 (11.7%) with ALT elevation to 2-5X ULN [group A-1] and 21 (8.2%) flared to >5X ULN [group A-2]. The magnitude of qHBsAg decline and rate of "rapid HBsAg decline" by month 6 was significantly greater and more frequent in group A (-0.446 vs -0.042 log₁₀ IU/mL; 45.1 vs 8.8%, respectively, P = 0.000) than in the remaining 205 patients without on-treatment ALT elevation (group B), being greatest in patients with hepatitis flare (group A-2: -0.559 log₁₀ IU/mL and 57.1%, respectively). In patients with therapy ≥2 years, patients with "on-treatment ALT elevation" also showed significantly greater annual HBsAg decline, more frequent to <100 IU/mL and 4 times higher HBsAg seroclearance rate. "On-treatment ALT elevation," especially flare >5X ULN, during entecavir therapy or tenofovir therapy may enhance/accelerate HBsAg decline, suggesting the effect of immune restoration upon potent viral suppression.

HBsAg Loss with Peg-interferon Alfa-2a in Hepatitis B Patients with Partial Response to Nucleos(t)ide Analog: New Switch Study

Background and Aims: Hepatitis B surface antigen (HBsAg) loss is seldom achieved with nucleos(t)ide analog (NA) therapy in chronic hepatitis B patients but may be enhanced by switching to finite pegylated-interferon (Peg-IFN) alfa-2a. We assessed HBsAg loss with 48- and 96-week Peg-IFN alfa-2a in chronic hepatitis B patients with partial response to a previous NA. Methods: Hepatitis B e antigen (HBeAg)-positive patients who achieved HBeAg loss and hepatitis B virus DNA <200 IU/mL with previous adefovir, lamivudine or entecavir treatment were randomized 1:1 to receive Peg-IFN alfa-2a for 48 (n = 153) or 96 weeks (n = 150). The primary endpoint of this study was HBsAg loss at end of treatment. The ClinicalTrials.gov identifier is NCT01464281. Results: At the end of 48 and 96 weeks' treatment, 14.4% (22/153) and 20.7% (31/150) of patients, respectively, who switched from NA to Peg-IFN alfa-2a cleared HBsAg. Rates were similar irrespective of prior NA or baseline HBeAg seroconversion. Among those who cleared HBsAg by the end of 48 and 96 weeks' treatment, 77.8% (14/18) and 71.4% (20/28), respectively, sustained HBsAg loss for a further 48 weeks. Baseline HBsAg <1500 IU/mL and week 24 HBsAg <200 IU/mL were associated with the highest rates of HBsAg loss at the end of both 48- and 96-week treatment (51.4% and 58.7%, respectively). Importantly, extending treatment from 48 to 96 weeks enabled 48.3% (14/29) more patients to achieve HBsAg loss. Conclusions: Patients on long-term NA who are unlikely to meet therapeutic goals can achieve high rates of HBsAg loss by switching to Peg-IFN alfa-2a. HBsAg loss rates may be improved for some patients by extending treatment from 48 to 96 weeks, although the differences in our study cohort were not statistically significant. Baseline and on-treatment HBsAg may predict HBsAg loss with Peg-IFN alfa-2a.

Long-Term Follow-up and Quantitative Hepatitis B Surface Antigen Monitoring in North American Chronic HBV Carriers

INTRODUCTION

Quantitative hepatitis B surface antigen (qHBsAg) combined with HBV DNA may be useful for predicting chronic hepatitis B (CHB) activity and nucleoside analogue (NA) response.

MATERIAL AND METHODS

In this retrospective cohort study we evaluated qHBsAg levels according to CHB disease phase and among patients on treatment. Random effect logistic regression analysis was used to analyze qHBsAg change with time in the NA-treated cohort.

RESULTS

545 CHB carriers [56% M, median age 48 y (IQR 38-59), 73% Asian] had qHBsAg testing. In the untreated group (44%), 8% were classified as immune tolerant, 10% immune clearance, 40% inactive, and 43% had HBeAg- CHB and the median HBsAg levels were 4.6 (IQR 3.4-4.9), 4.0 (IQR 3.4-4.5), 2.9 (IQR 1.4-3.8), and 3.2 log IU/mL (IQR 2.6-4.0), respectively; p < 0.001. In the NA-treated group (28% entecavir, 68% tenofovir, 4% lamivudine), no significant change in qHBsAg levels occured with time. However, 19% of patients on long-term NA had sustained qHBsAg < 2 log10 IU/mL.

CONCLUSION

qHBsAg titers were associated with CHB phase and remained stable in those on long-term NA. A significant number of treated patients had low-level qHBsAg, of which some may be eligible for treatment discontinuation without risk of flare.