Performance of the cobas® HBV RNA Automated Investigational Assay for the Detection and Quantification of Circulating HBV RNA in Chronic HBV Patients

HBcrAg and cirB-RNA Do Not Predict Clinical and Virological Outcomes in Patients With HBeAg-Negative Chronic Infection

BACKGROUND & AIMS

Predicting clinical and virological outcomes in HBeAg-negative (HBeAg-neg) chronic infection often requires long-term monitoring. Our study explored whether a single measurement of quantitative HBsAg (qHBsAg), HBV core-related antigen (HBcrAg), and circulating HBV RNA (cirB-RNA) can define the natural course of untreated HBeAg-neg chronic infection patients.

METHODS

To this aim, we included 128 naïve HBeAg-neg chronic infection patients, stratified according to qHBsAg levels in: (1) 10-1000 IU/mL, (2) 1000-10 000 IU/mL, and (3) > 10 000 IU/mL.

RESULTS

HBcrAg and cirB-RNA were detected in 27% and 19% of patients with qHBsAg > 1000 IU/mL but rarely detected in patients with qHBsAg < 1000 IU/mL. After a median follow-up of 5.1 years, 9.4% of patients lost HBsAg, and 8.5% experienced an increase in HBV DNA > 2000 IU/mL. qHBsAg < 1000 IU/mL was the only factor independently associated with functional cure.

CONCLUSIONS

In untreated HBeAg-neg chronic infection patients, single-point cirB-RNA and HBcrAg do not offer additional predictive value over qHBsAg < 1000 IU/mL for spontaneous HBsAg loss.

HBV Recurrence Detected by HBV-Related Serum Markers and Immune Escape Mutations in Chronic Hepatitis B Patients Following Liver Transplantation

The posttransplantation recurrence rate of hepatitis B virus (HBV) infection in patients with chronic hepatitis B (CHB) is underestimated and linked with unfavorable outcomes. We investigated HBV recurrence by serum assays in patients with CHB following liver transplantation. We enrolled patients with CHB who underwent liver transplantation between March 2001 and July 2021 to participate in cross-sectional testing for HBV-related serum markers, including biochemical analysis for HBsAg and hepatitis B core-related antigen (HBcrAg) and real-time RT-PCR/PCR for HBV RNA and HBV DNA, in 2022. HBV recurrence in this study was defined as positive results of at least one posttransplantation HBV-related serum markers. Next-generation sequencing was performed for those with posttransplantation virological breakthroughs. Ninety-six patients with CHB who underwent liver transplantation were enrolled. Among 84 patients who received grafts negative for HBsAg, 41 (48.8%) exhibited HBV recurrence, and they tested positive for either HBsAg or HBcrAg, or both. High-risk patients, identified using a risk stratification model, had a higher likelihood of recurrence than low-risk patients (odds ratio: 2.59, 95% confidence interval: 1.06-6.35, p = 0.038). In 51 patients who tested negative for HBsAg after receiving HBsAg-negative grafts, 8 (15.7%) had positive HBcrAg, indicating occult HBV infection (OBI). We identified immune escape mutations and altered N-glycosylation patterns on the surface protein in patients experiencing virological breakthroughs following lamivudine resistance. HBsAg plus HBcrAg levels can be used to detect posttransplantation HBV recurrence. The OBI prevalence was higher in patients transplanted with HBsAg-negative liver grafts compared to blood donors, vaccinated young population, and community-based populations reported in literatures, possibly because of immune escape mutations or altered N-glycosylation patterns of surface proteins.

Hepatitis B virus DNA integration: Implications for diagnostics, therapy, and outcome

Hepatitis B virus (HBV) DNA integration - originally recognised as a non-functional byproduct of the HBV life cycle - has now been accepted as a significant contributor to HBV pathogenesis and hepatitis D virus (HDV) persistence. Integrated HBV DNA is derived from linear genomic DNA present in viral particles or produced from aberrantly processed relaxed circular genomic DNA following an infection, and can drive expression of hepatitis B surface antigen (HBsAg) and HBx. DNA integration events accumulate over the course of viral infection, ranging from a few percent during early phases to nearly 100 percent of infected cells after prolonged chronic infections. HBV DNA integration events have primarily been investigated in the context of hepatocellular carcinoma development as they can activate known oncogenes and other growth promoting genes, cause chromosomal instability and, presumably, induce epigenetic alterations, promoting tumour growth. More recent evidence suggests that HBsAg expression from integrated DNA might contribute to HBV pathogenesis by attenuating the immune response. Integrated DNA provides a source for envelope proteins required for HDV replication and hence represents a means for HDV persistence. Because integrated DNA is responsible for persistence of HBsAg in the absence of viral replication it impacts established criteria for the resolution of HBV infection, which rely on HBsAg as a diagnostic marker. Integrated HBV DNA has been useful in assessing the turnover of infected hepatocytes which occurs during all phases of chronic hepatitis B including the initial phase of infection historically termed immune tolerant. HBV DNA integration has also been shown to impact the development of novel therapies targeting viral RNAs.

Limited stability of Hepatitis B virus RNA in plasma and serum

Pregenomic hepatitis B virus RNA (HBV pgRNA) is a potential biomarker in the management of HBV infected patients. However, prior to the use in routine clinical practice potential confounders of test results need to be identified. This study investigates the stability of HBV pgRNA under various storage conditions. HBV-RNA level of 26 HBV patients were determined using the Roche cobas® 6800/8800 investigational HBV-RNA assay. Plasma and serum were stored for 6,48,169 h at 4,25 and 42 °C, respectively. Additionally, 10 serum and plasma samples underwent 4 or 11 cycles of freezing (-80 °C) and thawing (25 °C). A significant decline in mean pgRNA concentration compared to baseline was observed after storage for 48 h at 25 °C as well as after 6 h of storage at 42 °C. Accordingly, sub-analyses of predefined pgRNA baseline concentrations (≤ 10 cp/mL, > 10-100 cp/ml, > 100 cp/mL) revealed significant changes in pgRNA level after storage at 25 and 42 °C. No effect of freezing and thawing on pgRNA level was observed. A qualitative detection of HBV pgRNA is feasible in samples with > 100 cp/mL up to 48 h under storage temperatures of 4-42 °C. For most stable quantitative HBV pgRNA values storage at 4 °C should be preferred.

HBV Biomarkers and Their Role in Guiding Treatment Decisions

Over 300 million individuals worldwide are chronically infected with hepatitis B virus and at risk for progressive liver disease. Due to the lack of a therapy that reliably achieves viral elimination and the variability of liver disease progression, treatment decisions are guided by the degree of liver disease and viral biomarkers as the viral life-cycle is well characterized and largely conserved between individuals. In contrast, the immunological landscape is much more heterogeneous and diverse and the measurement of its components is less well standardized. Due to the lack of a universal and easily measurable set of biomarkers, clinical practice guidelines remain controversial, aiming for a balance between simplifying treatment decisions by reducing biomarker requirements and using all available biomarkers to avoid overtreatment of patients with low risk for disease progression. While approved therapies such as nucleos(t)ide analogs improve patient outcomes, the inability to achieve a complete cure highlights the need for novel therapies. Since no treatment candidate has demonstrated universal efficacy, biomarkers will remain important for treatment stratification. Here, we summarize the current knowledge on virological and immunological biomarkers with a specific focus on how they might be beneficial in guiding treatment decisions in chronic hepatitis B.

Circulating HBV RNA and Hepatitis B Core-Related Antigen Trajectories in Persons With HIV/HBV Coinfection and Hepatitis B Surface Antigen Loss During Tenofovir Therapy

BACKGROUND

We evaluated long-term trajectories of circulating hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) in persons with and without hepatitis B surface antigen (HBsAg) loss during tenofovir therapy in the Swiss HIV Cohort Study.

METHODS

We included 29 persons with HIV with HBsAg loss and 29 matched persons with HIV without HBsAg loss. We compared HBV RNA and HBcrAg decline and assessed the cumulative proportions with undetectable HBV RNA and HBcrAg levels during tenofovir therapy using Kaplan-Meier estimates.

RESULTS

HBsAg loss occurred after a median of 4 years (IQR, 1-8). All participants with HBsAg loss achieved suppressed HBV DNA and undetectable HBV RNA preceding undetectable quantitative HBsAg levels, whereas 79% achieved negative HBcrAg. In comparison, 79% of participants without HBsAg loss achieved undetectable HBV-RNA and 48% negative HBcrAg. After 2 years of tenofovir therapy, an HBV RNA decline ≥1 log10 copies/mL had 100% sensitivity and 36.4% specificity for HBsAg loss, whereas an HBcrAg decline ≥1 log10 U/mL had 91.0% sensitivity and 64.5% specificity.

CONCLUSIONS

HBV RNA suppression preceded undetectable quantitative HBsAg levels and had high sensitivity but low specificity for HBsAg loss during tenofovir therapy in persons with HIV. HBcrAg remained detectable in approximately 20% of persons with HBsAg loss and 50% of persons without HBsAg loss.

Newer Diagnostic Virological Markers for Hepatitis B Virus Infection

Chronic Hepatitis B (CHB) remains a major public health problem, leading to various complications such as liver fibrosis, cirrhosis, and hepatocellular carcinoma. The existing diagnostic markers for Hepatitis B virus (HBV) are limited in distinguishing different CHB phases and intra-hepatic viral replication activity. In the past few years, several non-invasive potential blood markers that reflect viral intra-hepatic replicative state more accurately have been in progress and are gaining importance. Despite substantial efforts, the clinical utility of these new markers in CHB management is limited and unexplored. Therefore, in this review, we will discuss some of the newer HBV markers, their potential role in the diagnosis and monitoring of CHB patients.

How to cite this article

Agarwal R, Gupta E, Samal J, et al. Newer Diagnostic Virological Markers for Hepatitis B Virus Infection. Euroasian J Hepato-Gastroenterol 2024;14(2):214-220.

Clinical performance of Circulating HBV RNA and iTACT-HBcrAg Assays in HBeAg-negative and HBsAg-cleared Chronic Hepatitis B Patients

Hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) have been reported to reflect the transcriptional activity of covalently closed circular HBV DNA. We retrospectively investigated the proportions of quantifiable serum HBV RNA and immunoassay for total antigen including complex via pretreatment-hepatitis B core-related antigen (iTACT-HBcrAg) in chronic hepatitis B patients negative for hepatitis B e antigen (HBeAg) and/or with hepatitis B surface antigen (HBsAg) seroclearance. This study included 246 HBeAg-negative HBV-infected patients, who comprised 13 with liver cirrhosis (LC, the LC group), 118 chronic hepatitis (CH, the CH group), and 115 inactive carriers (IC, the IC group), and 44 patients with HBsAg seroclearance. iTACT-HBcrAg and HBV RNA levels were determined using stored serum samples. Higher proportions of the patients had quantifiable iTACT-HBcrAg than HBV RNA in all groups of HBeAg-negative patients (iTACT-HBcrAg: 84.6%, 90.7%, 35.7%, HBV RNA: 23.1%, 26.3%, 14.8%, for the LC, CH, IC groups). With HBsAg seroclearance (HBsAg <0.05 IU/mL), the proportions of quantifiable samples for HBV RNA were also lower than iTACT-HBcrAg (0% for HBV RNA). Thus, iTACT-HBcrAg was more often detectable than circulating HBV RNA in this study population. Further long-term prospective evaluation of iTACT-HBcrAg is desirable for its utilization in clinical practice.

Performance Evaluation of the Roche Cobas 5800 HBV and HCV Tests: Comparison of the 200 and 500 μL Protocols

Background

Clinical management of patients infected with hepatitis B virus (HBV) or hepatitis C virus (HCV) relies on the viral load (VL). The Cobas 5800 system (Roche Diagnostics) can determine VLs in 200 and 500 μL samples, but the performance of each protocol has not been compared. We evaluated the performance of both protocols for the HBV and HCV tests.

Methods

Precision and linearity were verified using commercial panels. Probit analyses were used to determine limits of detection (LoDs). The results obtained with 336 samples were compared using the 200 and 500 μL protocols. Data from 6,737 retrospective HBV and 768 HCV samples were compared to estimate the effects of the different LoDs on the diagnostic results of the protocols. Correlations between protocols were tested with Spearman's rank correlation coefficients (rho).

Results

The precision and linearity of both protocols were verified. The LoDs for the 200 and 500 μL protocols were 6.5 and 2.7 IU/mL for HBV and 29.7 and 8.2 IU/mL for HCV, respectively. The agreement between the protocols ranged from 0.8 to 1.0. The results obtained with the HBV and HCV tests showed a strong correlation (rho=0.994). Only 0.4% of HBV and 0.4% of HCV test results were affected by the LoDs of the 200 μL protocol.

Conclusions

The Cobas 5800 200 and 500 μL protocols for the HBV DNA and HCV RNA tests demonstrated excellent performance. These findings establish the 200 μL protocol as a new option for low-volume samples, especially for pediatric and difficult-to-bleed patients.

Biogenesis of serum HBV RNA and clinical phenomena of serum HBV RNA in chronic hepatitis B patients before and after receiving nucleos(t)ide analogues therapy

There are estimated 300 million people afflicted with chronic hepatitis B (CHB) worldwide. The risk of liver cirrhosis and hepatocellular carcinoma (HCC) increases considerably with chronic hepatitis B infection. While current therapeutics are effective in controlling hepatitis B virus (HBV) infection and disease progression, a cure for HBV infection remains unattainable due to an intranuclear replicative intermediate known as covalently closed circular DNA (cccDNA). It has recently been shown that serum HBV RNA is a non-invasive biomarker that reflects cccDNA transcriptional activity. This review provides a comprehensive overview and the latest updates on the molecular characteristics and clinical significance of serum HBV RNA, such as species of serum HBV RNA, forms of serum HBV RNA carriers and predictive value for relapses in CHB patients after nucleos(t)ide analogues (NAs) discontinuation and development of liver fibrosis and HCC. Furthermore, we summarize standardized assays for testing serum HBV RNA, the dynamic changes of serum HBV RNA levels in treatment-naïve CHB patients and those under NAs therapy, as well as the host and viral influencing factors of serum HBV RNA levels. Finally, we discuss the future perspectives in studies of serum HBV RNA.

Efficacy, safety, and pharmacokinetics of capsid assembly modulator linvencorvir plus standard of care in chronic hepatitis B patients

BACKGROUND/AIMS

Four-week treatment of linvencorvir (RO7049389) was generally safe and well tolerated, and showed anti-viral activity in chronic hepatitis B (CHB) patients. This study evaluated the efficacy, safety, and pharmacokinetics of 48-week treatment with linvencorvir plus standard of care (SoC) in CHB patients.

METHODS

This was a multicentre, non-randomized, non-controlled, open-label phase 2 study enrolling three cohorts: nucleos(t)ide analogue (NUC)-suppressed patients received linvencorvir plus NUC (Cohort A, n=32); treatment-naïve patients received linvencorvir plus NUC without (Cohort B, n=10) or with (Cohort C, n=30) pegylated interferon-α (Peg-IFN-α). Treatment duration was 48 weeks, followed by NUC alone for 24 weeks.

RESULTS

68 patients completed the study. No patient achieved functional cure (sustained HBsAg loss and unquantifiable HBV DNA). By Week 48, 89% of treatment-naïve patients (10/10 Cohort B; 24/28 Cohort C) reached unquantifiable HBV DNA. Unquantifiable HBV RNA was achieved in 92% of patients with quantifiable baseline HBV RNA (14/15 Cohort A, 8/8 Cohort B, 22/25 Cohort C) at Week 48 along with partially sustained HBV RNA responses in treatment-naïve patients during follow-up period. Pronounced reductions in HBeAg and HBcrAg were observed in treatment-naïve patients, while HBsAg decline was only observed in Cohort C. Most adverse events were grade 1-2, and no linvencorvir-related serious adverse events were reported.

CONCLUSION

48-week linvencorvir plus SoC was generally safe and well tolerated, and resulted in potent HBV DNA and RNA suppression. However, 48-week linvencorvir plus NUC with or without Peg-IFN did not result in the achievement of functional cure in any patient.

Quantification of circulating HBV RNA expressed from intrahepatic cccDNA in untreated and NUC treated patients with chronic hepatitis B

OBJECTIVE

A convenient, reproducible biomarker of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) transcriptional activity is lacking. We measured circulating HBV RNA (cirB-RNA) in untreated and nucleos(t)ide analogues (NUC) treated chronic hepatitis B (CHB) patients to define its correlation with intrahepatic viral markers and HBV core-related antigen (HBcrAg).

DESIGN

Paired liver biopsy and serum samples were collected from 122 untreated and 30 NUC-treated CHB patients. We measured cirB-RNA, HBV DNA, hepatitis B surface antigen (HBsAg), HBcrAg and alanine aminotransferase levels. cirB-RNA was quantified using an investigational HBV RNA assay for use on the cobas 6800 system. The test detects a region spanning the HBV canonical polyadenylation site. cccDNA and 3.5 kb RNA in liver tissue were assessed by quantitative PCR and droplet digital PCR.

RESULTS

cirB-RNA was detectable in 100% of HBeAg(+) chronic hepatitis (CH), 57% and 14% of HBeAg(-) CH and chronic infection untreated patients and 47% of NUC-treated patients. cirB-RNA undetectability was associated with lower intrahepatic cccDNA transcriptional activity, as well as serum HBcrAg, but no significant differences in HBsAg, in both untreated and treated patients. In untreated HBeAg(-) patients, cirB-RNA correlated with intrahepatic 3.5 kb RNA and cccDNA transcriptional activity, serum HBV DNA and HBcrAg, but not with HBsAg or total cccDNA levels. Combined undetectability of both cirB-RNA and HBcrAg detection in untreated HBeAg(-) patients identified a subgroup with the lowest levels of intrahepatic transcriptionally active cccDNA.

CONCLUSION

Our results support the usefulness of quantification of circulating HBV RNA expressed from cccDNA as an indicator of intrahepatic active viral reservoir in both untreated and NUC-treated CHB patients.

TRIAL REGISTRATION NUMBER

NCT02602847.

Baseline serum HBV RNA is associated with the risk of hepatitis flare after stopping nucleoside analog therapy in HBeAg-negative participants

BACKGROUND AND AIMS

HBV RNA in peripheral blood reflects HBV cccDNA transcriptional activity and may predict clinical outcomes. The prospective Melbourne HBV-STOP trial studied nucleot(s)ide analog discontinuation in HBeAg-negative non-cirrhotic participants with long-term virological suppression. Ninety-six weeks after stopping treatment, the proportion of participants with virological relapse (HBV DNA > 2000 IU/mL), biochemical relapse (ALT > 2 × ULN and HBV DNA > 2000 IU/mL), or hepatitis flare (ALT > 5 × ULN and HBV DNA > 2000 IU/mL) was 89%, 58%, and 38%, respectively. We evaluated the ability of serum HBV RNA levels to predict these outcomes.

APPROACH RESULTS

HBV RNA levels were measured using the Roche cobas 6800/8800 HBV RNA Investigational Assay. Sixty-five participants had baseline and longitudinal off-treatment specimens available for RNA testing. HBV RNA was detectable at baseline in 25% of participants and was associated with a higher risk of biochemical relapse (81% vs. 51%, p value 0.04) and hepatitis flare (63% vs. 31%, p value 0.04). Participants who had undetectable serum HBV RNA as well as HBsAg ≤ 100 IU/mL at baseline were less likely to experience virological relapse (4 of 9, 44%) than participants with detectable HBV RNA and HBsAg level > 100 IU/mL (15/15, 100%; p value 0.0009). Off-treatment levels of HBV RNA were correlated with HBV DNA and were associated with the risk of hepatitis flare.

CONCLUSIONS

Serum HBV RNA may be a useful biomarker for guiding clinical decision-making before stopping nucleot(s)ide analog therapy. Baseline HBV RNA and HBsAg levels are associated with the risk of clinical relapse, hepatitis flare, and disease remission off-treatment.

Assessment of the cobas® HBV RNA investigational assay in the setting of nucleoside analog therapy cessation

HBV RNA is used as a marker of cccDNA transcription and is applicable in the setting of nucleos(t)ide analog (NA) treatment, which suppresses HBV DNA. Traditional assays for quantification of HBV RNA rely on labor-intensive 3'RACE assays targeting the polyA tail. In this study, the high-throughput Roche cobas®HBV RNA investigational assay was assessed on the Roche cobas® 6800 automated platform. Of 969 samples collected for a NA treatment cessation trial, and tested on the cobas assay, 249 were analyzed for sensitivity, reproducibility, sample type applicability, and results were compared to a RACE-based assay. Results of 97 paired serum and plasma samples demonstrated an excellent correlation of 0.98. However, 14.5% of plasma samples yielded detectable (below the limit of quantification) results, when the paired serum was undetectable, and plasma was shown to yield a statistically significant (p < 0.001) greater mean 0.119 log₁₀ copies/ml. Quantification of 152 samples showed good correlation (0.91) between the cobas and RACE assays. The cobas assay demonstrated superior lower limit of quantification, 10 copies/ml, which resulted in detection of 13.2% more samples than the RACE assay. Reproducibility and linear range of the automated assay were also confirmed. The Roche cobas assay for HBV RNA is sensitive and highly recommended.

Characterization of hepatitis B viral forms from patient plasma using velocity gradient: Evidence for an excess of capsids in fractions enriched in Dane particles

Hepatitis B virus (HBV) morphogenesis is characterized by a large over-production of subviral particles and recently described new forms in parallel of complete viral particles (VP). This study was designed to depict circulating viral forms in HBV infected patient plasmas, using velocity gradients and most sensitive viral markers. Plasmas from chronic hepatitis B (CHB) patients, HBeAg positive or negative, genotype D or E, were fractionated on velocity and equilibrium gradients with or without detergent treatment. Antigenic and molecular markers were measured in plasma and in each collected fraction. Fast Nycodenz velocity gradients revealed good reproducibility and provided additional information to standard equilibrium sucrose gradients. HBV-RNAs circulated as enveloped particles in all plasmas, except one, and at lesser concentrations than VP. Calculations based on standardized measurements and relative virion and subviral particle molecular stoichiometry allowed to refine the experimental approach. For the HBeAg-positive plasma, VP were accompanied by an overproduction of enveloped capsids, either containing HBs, likely corresponding to empty virions, or for the main part, devoid of this viral envelope protein. Similarly, in the HBeAg-negative sample, HBs enveloped capsids, likely corresponding to empty virions, were detected and the presence of enveloped capsids devoid of HBs protein was suspected but not clearly evidenced due to the presence of contaminating high-density subviral particles. While HBeAg largely influences HBcrAg measurement and accounts for two-thirds of HBcrAg reactivity in HBeAg-positive patients, it remains a 10 times more sensitive marker than HBsAg to characterize VP containing fractions. Using Nycodenz velocity gradients and standardized biomarkers, our study proposes a detailed characterization of circulating viral forms in chronically HBV infected patients. We provide evidence for an excess of capsids in fractions enriched in Dane particles, likely due to the presence of empty virions but also by capsids enveloped by an HBs free lipid layer. Identification of this new circulating viral particle sets the basis for studies around the potential role of these entities in hepatitis B pathogeny and their physiological regulation.

Viral Diagnosis of Hepatitis B and Delta: What We Know and What Is Still Required? Specific Focus on Low- and Middle-Income Countries

To achieve the World Health Organization's (WHO) goals of eradicating viral hepatitis globally by 2030, the regional prevalence and epidemiology of hepatitis B virus (HBV) and hepatitis delta virus (HDV) coinfection must be known in order to implement preventiveon and treatment strategies. HBV/HDV coinfection is considered the most severe form of vira l hepatitis due to it's rapid progression towards cirrhosis, hepatocellular carcinoma, and liver-related death. The role of simplified diagnosticsis tools for screening and monitoring HBV/HDV-coinfected patients is crucial. Many sophisticated tools for diagnoses have been developed for detection of HBV alone as well as HBV/HDV coinfection. However, these advanced techniques are not widely available in low-income countries and there is no standardization for HDV detection assays, which are used for monitoring the response to antiviral therapy. More accessible and affordable alternative methods, such as rapid diagnostic tests (RDTs), are being developed and validated for equipment-free and specific detection of HBV and HDV. This review will provide some insight into both existing and diagnosis tools under development, their applicability in developing countries and how they could increase screening, patient monitoring and treatment eligibility.