Hepatitis B Core-Related Antigen as Surrogate Biomarker of Intrahepatic Hepatitis B Virus Covalently-Closed-Circular DNA in Patients with Chronic Hepatitis B: A Meta-Analysis

Assessing the virological response to direct-acting antiviral therapies in the HBV cure programme

Hepatitis B virus (HBV) is a global health problem with over 250 million people affected worldwide. Nucleos(t)ide analogues remain the standard of care and suppress production of progeny virions; however, they have limited effect on the viral transcriptome and long-term treatment is associated with off-target toxicities. Promising results are emerging from clinical trials and several drug classes have been evaluated, including capsid assembly modulators and RNA interfering agents. Whilst peripheral biomarkers are used to monitor responses and define treatment endpoints, they fail to reflect the full reservoir of infected hepatocytes. Given these limitations, consideration should be given to the merits of sampling liver tissue, especially in the context of clinical trials. In this review article, we will discuss methods for profiling HBV in liver tissue and their value to the HBV cure programme.

Prediction of intrahepatic covalently closed circular DNA levels in patients with resolved hepatitis B virus infection: Impact of serum antibody to hepatitis B core antigen titers

AIM

The correlation between intrahepatic covalently closed circular DNA (cccDNA) levels and serum hepatitis B virus (HBV) markers in patients with resolved HBV infection (hepatitis B surface antigen [HBsAg]-negative and antibody to hepatitis B core antigen [anti-HBc]-positive) is unclear. We therefore examined the utility of anti-HBc titers as a surrogate marker of intrahepatic cccDNA levels in patients with resolved HBV infections.

METHODS

Among 1005 patients who underwent hepatectomy between 2010 and 2018, a retrospective review was performed in 114 patients (76 with resolved HBV infection and 38 HBsAg-positive) with frozen specimens of the background liver. Clinical, biochemical, and virological data, including intrahepatic cccDNA levels, were retrospectively evaluated. Intrahepatic cccDNA levels were measured using droplet digital polymerase chain reaction.

RESULTS

Intrahepatic cccDNA levels positively correlated with serum HBsAg levels (r = 0.609, p < 0.001) and anti-HBc titers (r = 0.542, p < 0.001). An intrahepatic cccDNA level of 22.2 copies/μg was the optimal cut-off for HBsAg positivity, with a sensitivity of 86.8% and specificity of 89.5%. Of the 76 cases with resolved HBV infection, 8 had high levels of intrahepatic cccDNA (≥22.2 copies/μg). Multivariate analyses showed that anti-HBc ≥ 11.0 sample/cut-off (S/CO) was an independent risk factor for high intrahepatic cccDNA levels (odds ratio, 12.6; 95% confidence interval, 2.4-66.156; P = 0.003).

CONCLUSIONS

Anti-HBc titers were positively correlated with intrahepatic cccDNA levels. Even in patients with resolved HBV infection, anti-HBc ≥ 11.0 S/CO was considered to indicate high intrahepatic cccDNA levels, comparable to those in HBsAg-positive cases. In this group, careful monitoring is required during immunosuppressive therapy to prevent HBV reactivation.

High end-of-treatment hepatitis B core-related antigen levels predict hepatitis flare after stopping nucleot(s)ide analogue therapy

BACKGROUND AND AIMS

Accurate biomarkers to predict outcomes following discontinuation of nucleos(t)ide analogue (NA) therapy are needed. We evaluated serum hepatitis B core-related antigen (HBcrAg) level as a biomarker for predicting outcomes after NA discontinuation.

METHODS

Patients with HBeAg-negative chronic hepatitis B (CHB) without cirrhosis were enrolled in a prospective trial evaluating clinical outcomes until 96 weeks after NA discontinuation. End of treatment (EOT) and off-treatment levels of serum HBcrAg, HBsAg, HBV RNA and HBV DNA were used to predict key clinical outcomes including hepatitis flare (ALT ≥5 × ULN and HBV DNA > 2000 IU/mL). The SCALE-B score was calculated for the purposes of model validation.

RESULTS

HBcrAg was tested amongst 65 participants. The median age was 54 years, 54% were male and 83% were Asian. HBcrAg was detectable in 86% patients. HBcrAg level ≥4 log U/mL at EOT was predictive of hepatitis flare [8/10 (80%) vs. 17/55 (31%), p = .001]. The presence of either HBcrAg ≥4 log U/mL or detectable HBV RNA at EOT predicted for both biochemical relapse and hepatitis flare. The SCALE-B model at EOT predicted for virological relapse, biochemical relapse, hepatitis flare and HBsAg loss in this cohort. An increase in the serum HBcrAg level off-treatment was also associated with hepatitis flare. No participant with EOT HBcrAg level ≥4 log U/mL achieved HBsAg loss.

CONCLUSIONS

High levels of serum HBcrAg predict for hepatitis flare after stopping NA therapy and low likelihood of HBsAg loss at week 96. People with high levels of serum HBcrAg are not suitable candidates for NA discontinuation.

The significance of detecting HBV pgRNA and HBcrAg in HBV patients treated with NAs

The value of detecting hepatitis B virus (HBV), pregenomic RNA (pgRNA), and hepatitis B core-related antigen (HBcrAg), both separately and jointly, in the management of HBV patients undergoing treatment with Nucleotide Analog was investigated. A total of 149 HBV patients who were being treated with Nucleotide Analog were enrolled in this study. The quantitative levels of HBV pgRNA and HBcrAg in the sera of these patients were determined, aiming to comprehend their replication levels and expression during the course of antiviral therapy. The patients were separated into 3 groups based on treatment duration: treatment time ≤ 12 months, treatment time ranging from 12 months to <60 months, and treatment time ≥ 60 months. Significantly different levels of HBcrAg and HBV pgRNA were observed among 3 groups (P < .05). In the group of patients with positive hepatitis B e antigen, both HBcrAg and pgRNA levels were higher compared to the group with negative hepatitis B e antigen, and this difference between the 2 groups was found to be statistically significant. Stratified analysis based on levels of hepatitis B surface antigen (HBsAg) revealed that the group with HBsAg levels < 100 IU/mL had lower levels of both HBcrAg and pgRNA compared to the group with HBsAg levels ≥ 100 IU/mL (P < .001). Following antiviral therapy, various degrees of transcription of covalently closed circular DNA continue to exist within the liver of HBV patients. The levels of serum HBcrAg and HBV pgRNA vary among patients with different treatment durations, indicating their efficacy in evaluating disease conditions during antiviral therapy.

Interpreting Serogical Markers in Hepatitis B Virus Infection

Hepatitis B virus (HBV) is considered a global health-related problem. The World Health Organization estimates an incidence of approximately 1.5 million new cases annually despite an available effective vaccine, and approximately 296 million people worldwide are living with chronic hepatitis B. This large number of patients require continuous monitoring of the treatment efficacy, disease progression, and screening for the HBV-related liver complications. Recently, it has become more evident that we need better predictive markers to allow treatment cessation when there is a reduced risk of viral reactivation, in addition to the present need to predict disease outcome and improve the management of people living with chronic hepatitis B. Novel HBV biomarkers are focused on in this minireview. These new markers include quantification of serum HBV RNA, hepatitis B core–related antigen, quantitative hepatitis B surface antigen, quantitative anti–hepatitis B core antigen, and detection of HBV nucleic acid–related antigen. The target of finding new markers for HBV replication is to provide crucial clinical data in a noninvasive way for detecting the replicative and transcriptional activity of the virus. This may support better management of patients compared with the criterion-standard invasive marker for detecting the intrahepatic replication and transcription of HBV, which is the quantification of covalently closed circular DNA.

Chronic hepatitis B virus infection and fibrosis: novel non-invasive approaches for diagnosis and risk stratification

Despite the availability of an effective vaccination, chronic hepatitis B virus (HBV) infection is still a major health concern worldwide. Chronic HBV infection can lead to fibrosis accumulation and overtime to cirrhosis, the principal risk factor for liver failure and hepatocellular carcinoma development. Liver biopsy is still considered the gold standard for fibrosis assessment, even though it is invasive and not exempt of complications. Overtime, several non-invasive methods for the detection of liver fibrosis have been developed and gradually introduced into clinical practice. However, their main limitation is the poor performance for the detection of intermediate stages of fibrosis. Finally, novel serological biomarkers, polygenic risk scores and imaging methods have been proposed in last years as novel promising tools to correctly identify the degree of liver fibrosis and to monitor liver disease progression. In this narrative review, we provide an overview on the novel non-invasive approaches for the evaluation of liver fibrosis and risk stratification of patients with chronic hepatitis B.

Review article: novel biomarkers in hepatitis B infection

BACKGROUND

Chronic hepatitis B remains a global health problem with an estimated 296 million people affected worldwide. Individuals are at risk of serious complications such as cirrhosis and hepatocellular carcinoma and accurately predicting these clinical endpoints has proven difficult. However, several viral biomarkers have recently been developed, including quantitative HBV surface antigen (qHBsAg), hepatitis B RNA (HBV RNA) and core-related antigen (HBcrAg), and shown promise in a range of clinical settings.

AIMS

To critically appraise these novel biomarkers, exploring their potential uses, availability of assays and areas for future development.

METHODS

We performed a literature search of PubMed, identifying articles published in the field of hepatitis B biomarkers between 2010 and 2022.

RESULTS

Novel biomarkers such as HBcrAg, HBV RNA and qHBsAg may be useful in predicting treatment outcomes, stratifying the risk of future complications and estimating off-treatment viral reactivation. Furthermore, HBV RNA and HBcrAg titres may accurately reflect cccDNA transcriptional activity, and this is particularly informative in the context of nucleoside analogue therapy. On a cautionary note, most studies have been performed in Caucasian or Asian populations, and methods for detecting HBV RNA lack standardisation.

CONCLUSION

Novel viral biomarkers have the potential to provide additional insights into the natural history of infection and allow a more bespoke, cost-effective framework of care. However, access remains limited, and further efforts are needed to validate their use in ethnically diverse populations, confirm predictive cut-off values, and establish their role in the era of novel antiviral therapies.

Hepatitis B Core-Related Antigen Is Useful for Predicting Phase and Prognosis of Hepatitis B e Antigen-Positive Patients

The role of hepatitis B core-related antigen (HBcrAg) level in defining clinical phase and predicting prognosis of chronic hepatitis B (CHB) has not been fully studied. CHB patients who had undergone liver biopsy in Korea University Medical Center were included. Patients with liver cirrhosis were excluded. The associations of HBcrAg level with CHB phase, and nucleos(t)ide analogue (NA)-induced hepatitis B e antigen (HBeAg) seroconversion were analyzed. In total, 387 patients (median follow-up of 82.4 months) were included. The CHB phases of patients were defined histologically as immune-tolerant (IT, n = 32, 8.3%), HBeAg-positive and immune-active (PIA, n = 211, 54.5%), HBeAg-negative and immune-active (n = 125, 32.3%), and inactive (n = 19, 4.9%), respectively. In HBeAg-positive patients, the mean HBV DNA levels were comparable between the two groups (p = 0.990). However, the mean HBsAg (7.4 log IU/mL and 6.9 log IU/mL, p = 0.002) and HBcrAg levels (8.2 log U/mL vs. 7.6 log U/mL, p < 0.001) of IT patients were significantly higher than that of PIA patients. In multivariate analysis, younger age (odds ratio [OR] 0.949, p = 0.025), lower alanine aminotransferase (OR 0.988, p = 0.002) and higher HBcrAg level (OR = 2.745 p = 0.022) were independent predictors of the IT phase. Of the patients in the PIA phase, 194 received NA after liver biopsy, and 61 (31.4%) had achieved HBeAg seroconversion after antiviral therapy. In Cox regression analysis, the higher HBcrAg level was the only independent predictor of the NA-induced HBeAg seroconversion (hazard ratio 1.285, p = 0.028). The HBcrAg level is useful for predicting clinical phase of CHB and NA-induced HBeAg seroconversion in HBeAg-positive patients.

The association between hepatocarcinogenesis and intracellular alterations due to hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a worldwide health problem leading to severe liver dysfunction, including liver cirrhosis and hepatocellular carcinoma. Although current antiviral therapies for chronic HBV infection have been improved and can lead to a strong suppression of viral replication, it is difficult to completely eliminate the virus with these therapies once chronic HBV infection is established in the host. Furthermore, chronic HBV infection alters intracellular metabolism and signalling pathways, resulting in the activation of carcinogenesis in the liver. HBV produces four viral proteins: hepatitis B surface-, hepatitis B core-, hepatitis B x protein, and polymerase; each plays an important role in HBV replication and the intracellular signalling pathways associated with hepatocarcinogenesis. In vitro and in vivo experimental models for analyzing HBV infection and replication have been established, and gene expression analyses using microarrays or next-generation sequencing have also been developed. Thus, it is possible to clarify the molecular mechanisms for intracellular alterations, such as endoplasmic reticulum stress, oxidative stress, and epigenetic modifications. In this review, the impact of HBV viral proteins and intracellular alterations in HBV-associated hepatocarcinogenesis are discussed.

Hepatitis B core related antigen in relation to intrahepatic and circulating viral markers, before and after combination therapy

INTRODUCTION AND OBJECTIVES

Covalently closed circular (ccc)DNA acts as a viral reservoir in the liver of patients with a chronic hepatitis B (CHB) infection and can only be quantified in liver biopsies. Hepatitis B core-related antigen (HBcrAg) levels in plasma/serum have been proposed to reflect intrahepatic cccDNA-levels and may therefore monitor treatment efficacy. This study aimed to validate the relationship between HBcrAg and other intrahepatic and circulating viral markers in CHB patients with high viral load, before and after combination treatment.

MATERIALS AND METHODS

Plasma/serum levels of HBcrAg, HBsAg, HBV-DNA, and HBV pregenomic RNA (HBV-pgRNA), and intrahepatic cccDNA and HBV-DNA levels and fibrosis scores were measured in 89 CHB patients with HBV-DNA levels of >100,000 copies/mL (17,182 IU/mL). Measurements were done before and after a 48-week treatment with pegylated interferon alfa-2a and adefovir in a prospective study (ISRCTN77073364).

RESULTS

Baseline HBcrAg-values correlated strongly with intrahepatic cccDNA (ρ 0.77, p < 0.001), intrahepatic HBV-DNA (ρ 0.73, p < 0.001) and plasma/serum HBV-DNA (ρ 0.80, p < 0.001), HBV-pgRNA (ρ 0.80, p < 0.001), and to lesser extend HBsAg (ρ 0.56, p < 0.001). Baseline HBcrAg-levels could not predict functional cure (FC) but HBcrAg-levels declined more strongly in patients who developed FC or HBeAg-loss. Furthermore, most correlations persisted at the end of treatment and follow-up.

CONCLUSIONS

HBcrAg reflects cccDNA transcription activity more accurately than HBsAg and may replace HBV-DNA as a marker during future treatment regimens, especially when cccDNA transcription is targeted or nucleot(s)ide analogues are included in the treatment regime.

Screening for Hepatocellular Carcinoma in Chronic Hepatitis B: An Update

(1) Background: Hepatocellular carcinoma (HCC) is an important cause of mortality in individuals with chronic hepatitis B infection, with screening of high-risk groups recommended in all major international guidelines. Our understanding of the risk factors involved has improved over time, encouraging researchers to develop models that predict future risk of HCC development. (2) Methods: A literature search of the PubMed database was carried out to identify studies that derive or validate models predicting HCC development in patients with chronic hepatitis B. Subsequently, a second literature search was carried out to explore the potential role of novel viral biomarkers in this field. (3) Results: To date, a total of 23 models have been developed predicting future HCC risk, of which 12 have been derived from cohorts of treatment-naïve individuals. Most models have been developed in Asian populations (n = 20), with a smaller number in Caucasian cohorts (n = 3). All of the models demonstrate satisfactory performance in their original derivation cohorts, but many lack external validation. In recent studies, novel viral biomarkers have demonstrated utility in predicting HCC risk in patients with chronic hepatitis B, amongst both treated and treatment-naïve patients. (4) Conclusion: Several models have been developed to predict the risk of HCC development in individuals with chronic hepatitis B infection, but many have not been externally validated outside of the Asian population. Further research is needed to refine these models and facilitate a more tailored HCC surveillance programme in the future.

Novel Biomarkers of Hepatitis B Virus and Their Use in Chronic Hepatitis B Patient Management

Even though an approved vaccine for hepatitis B virus (HBV) is available and widely used, over 257 million individuals worldwide are living with chronic hepatitis B (CHB) who require monitoring of treatment response, viral activity, and disease progression to reduce their risk of HBV-related liver disease. There is currently a lack of predictive markers to guide clinical management and to allow treatment cessation with reduced risk of viral reactivation. Novel HBV biomarkers are in development in an effort to improve the management of people living with CHB, to predict disease outcomes of CHB, and further understand the natural history of HBV. This review focuses on novel HBV biomarkers and their use in the clinical setting, including the description of and methodology for quantification of serum HBV RNA, hepatitis B core-related antigen (HBcrAg), quantitative hepatitis B surface antigen (qHBsAg), including ultrasensitive HBsAg detection, quantitative anti-hepatitis B core antigen (qAHBc), and detection of HBV nucleic acid-related antigen (HBV-NRAg). The utility of these biomarkers in treatment-naïve and treated CHB patients in several clinical situations is further discussed. Novel HBV biomarkers have been observed to provide critical clinical information and show promise for improving patient management and our understanding of the natural history of HBV.