Serum HBV RNA quantification: useful for monitoring natural history of chronic hepatitis B infection

Latest insights into the epidemiology, characteristics, and therapeutic strategies of chronic hepatitis B patients in indeterminate phase

As a hepatotropic virus, hepatitis B virus (HBV) can establish a persistent chronic infection in the liver, termed, chronic hepatitis B (CHB), which causes a series of liver-related complications, including fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HCC with HBV infection has a significantly increased morbidity and mortality, whereas it could be preventable. The current goal of antiviral therapy for HBV infection is to decrease CHB-related morbidity and mortality, and achieve sustained suppression of virus replication, which is known as a functional or immunological cure. The natural history of chronic HBV infection includes four immune phases: the immune-tolerant phase, immune-active phase, inactive phase, and reactivation phase. However, many CHB patients do not fit into any of these defined phases and are regarded as indeterminate. A large proportion of indeterminate patients are only treated with dynamic monitoring rather than recommended antiviral therapy, mainly due to the lack of definite guidelines. However, many of these patients may gradually have significant liver histopathological changes during disease progression. Recent studies have focused on the prevalence, progression, and carcinogenicity of indeterminate CHB, and more attention has been given to the prevention, detection, and treatment for these patients. Herein, we discuss the latest understanding of the epidemiology, clinical characteristics, and therapeutic strategies of indeterminate CHB, to provide avenues for the management of these patients.

Elevated hepatitis B virus RNA levels in HBeAg-positive patients with low-level viraemia or previous low-level viraemia

The understanding of viral transcription and replication activity in HBeAg-positive chronic hepatitis B (CHB) patients with low-level viraemia (LLV) or previous low-level viraemia (pre-LLV) remains unclear. Our aim was to evaluate and compare circulating hepatitis B virus (HBV) RNA levels in these patient groups with those achieving maintained virological response (MVR). This cross-sectional study included 147 patients: 43 in the LLV group, 25 in the pre-LLV group and 79 in the MVR group. Serum HBV RNA levels were assessed using specific RNA target capture combined with simultaneous amplification and testing method. Propensity score matching (PSM) was used to balance baseline characteristics between groups. Median HBV RNA levels were 6.9 copies/mL in the LLV group, 6.1 copies/mL in the pre-LLV group and 3.8 copies/mL in the MVR group. After PSM, significantly higher HBV RNA levels were observed in the LLV group compared to the MVR group (p < .001), and the pre-LLV group also showed higher HBV RNA levels than the MVR group (p < .001). Both LLV and pre-LLV HBeAg-positive CHB patients exhibited elevated circulating HBV RNA levels compared to those achieving MVR.

Profiles of HBcrAg and pgRNA in Pregnant Women With Chronic HBV Under Different Disease Phases and Antiviral Prophylaxis

Background

Pregnant women with chronic hepatitis B (CHB) exhibit unique clinical features in terms of postpartum immune system reconstitution and recovery from pregnancy-related changes. However, current studies focus primarily on the outcomes of maternal-infant transmission and postpartum hepatitis flares. We aimed to evaluate the profiles of hepatitis B core-related antigen (HBcrAg) and pregenomic RNA (pgRNA) in pregnant women with CHB.

Methods

This retrospective analysis included treatment-naïve pregnant women with CHB who were followed up regularly in an outpatient clinic from 2014 to 2021. Baseline HBcrAg and pgRNA levels were compared in patients with different disease phases. Changes in these parameters were examined in a subset of patients receiving antiviral prophylaxis. HBcrAg and pgRNA levels were measured before treatment, at 32 weeks of gestation, and postpartum.

Results

The final analysis included a total of 121 patients, 100 of whom were hepatitis B e antigen (HBeAg)-positive (96 and 4 in the immune-tolerant and -indeterminate phases, respectively) and 21 of whom were HBeAg-negative (6 and 15 in the immune-active and -inactive carrier phases, respectively). The HBeAg-negative group vs the HBeAg-positive group had lower levels of baseline HBcrAg (median [interquartile range {IQR}], 3.7 [3.0-5.9] vs 8.6 [8.4-8.7] log10 U/mL; P < .01) and pgRNA (median [IQR], 0.0 [0.0-2.5] vs 7.8 [7.6-8.1] log10 copies/mL; P < .01). The serum levels of HBcrAg and pgRNA were highest in immune-tolerant carriers and lowest in immune-inactive carriers. In HBeAg-positive patients, the correlation coefficients of HBcrAg and pgRNA with hepatitis B virus (HBV) DNA were 0.40 and 0.43, respectively; in HBeAg-negative patients, they were 0.53 and 0.51, respectively (all P < .05). The correlation coefficients with hepatitis B surface antigen (HBsAg) were 0.55 and 0.52 (P < .05) in HBeAg-positive patients, respectively, while in HBeAg-negative patients they were 0.42 and 0.37, respectively (P > .05). Among 96 patients receiving antiviral prophylaxis, we detected a rapid decrease in HBV DNA to an undetectable level during treatment but relatively stable levels of pgRNA and HBcrAg.

Conclusions

HBcrAg and pgRNA levels are lower in HBeAg-negative patients than in HBeAg-positive patients. These 2 markers are significantly associated with HBV DNA irrespective of HBeAg status, while they are significantly associated with HBsAg only in HBeAg-positive 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.

Selective detection of HBV pre-genomic RNA in chronic hepatitis B patients using a novel RT-PCR assay

In chronic hepatitis B (CHB) patients, quantification of HBV pgRNA in plasma has the potential to provide information on disease prognosis and liver injury or histopathology. However, current methods for detecting HBV pgRNA present technical difficulties due to the co-existence of HBV DNA in plasma samples. We have successfully established a novel one-step RT-PCR assay that allows selective quantification of HBV pgRNA. Two cohorts of participants were recruited for assay validation, including treatment-naïve patients with CHB and HBeAg-positive CHB patients who were treated with Tenofovir and monitored for 6 months to assess the predictive value of baseline HBV RNA for HBeAg seroclearance. Statistical analysis was performed using MedCalc version 20.019 software. The novel selective one-step RT-PCR assay for detecting HBV pgRNA was validated with a limit of detection of 100 copies/mL. The assay was able to selectively measure HBV pgRNA even in the presence of excess HBV rcDNA. In treatment-naïve CHB patients, HBV pgRNA levels were significantly lower than HBV DNA concentration. Serum HBV DNA levels and HBeAg status were positively associated with HBV pgRNA. Baseline serum HBV pgRNA levels were found to be strong predictors of HBeAg seroclearance after 6 months of Tenofovir treatment. The study presents a novel RT-PCR assay that allows accurate measurement of plasma HBV pgRNA in chronic hepatitis B patients, even in the presence of excess HBV DNA. The assay is highly selective and represents a significant advancement with potential for further breakthroughs in understanding the clinical significance of HBV pgRNA.

Hepatitis B virus serum RNA transcript isoform composition and proportion in chronic hepatitis B patients by nanopore long-read sequencing

Introduction

Serum hepatitis B virus (HBV) RNA is a promising new biomarker to manage and predict clinical outcomes of chronic hepatitis B (CHB) infection. However, the HBV serum transcriptome within encapsidated particles, which is the biomarker analyte measured in serum, remains poorly characterized. This study aimed to evaluate serum HBV RNA transcript composition and proportionality by PCR-cDNA nanopore sequencing of samples from CHB patients having varied HBV genotype (gt, A to F) and HBeAg status.

Methods

Longitudinal specimens from 3 individuals during and following pregnancy (approximately 7 months between time points) were also investigated. HBV RNA extracted from 16 serum samples obtained from 13 patients (73.3% female, 84.6% Asian) was sequenced and serum HBV RNA isoform detection and quantification were performed using three bioinformatic workflows; FLAIR, RATTLE, and a GraphMap-based workflow within the Galaxy application. A spike-in RNA variant (SIRV) control mix was used to assess run quality and coverage. The proportionality of transcript isoforms was based on total HBV reads determined by each workflow.

Results

All chosen isoform detection workflows showed high agreement in transcript proportionality and composition for most samples. HBV pregenomic RNA (pgRNA) was the most frequently observed transcript isoform (93.8% of patient samples), while other detected transcripts included pgRNA spliced variants, 3' truncated variants and HBx mRNA, depending on the isoform detection method. Spliced variants of pgRNA were primarily observed in HBV gtB, C, E, or F-infected patients, with the Sp1 spliced variant detected most frequently. Twelve other pgRNA spliced variant transcripts were identified, including 3 previously unidentified transcripts, although spliced isoform identification was very dependent on the workflow used to analyze sequence data. Longitudinal sampling among pregnant and post-partum antiviral-treated individuals showed increasing proportions of 3' truncated pgRNA variants over time.

Conclusions

This study demonstrated long-read sequencing as a promising tool for the characterization of the serum HBV transcriptome. However, further studies are needed to better understand how serum HBV RNA isoform type and proportion are linked to CHB disease progression and antiviral treatment response.

Evaluation of reverse transcription-polymerase chain reaction and simultaneous amplification and testing for quantitative detection of serum hepatitis B virus RNA

BACKGROUND

Chronic hepatitis B virus (HBV) infection is one of the common infectious diseases in the world. HBV covalently closed circular DNA (cccDNA) is the initial template of HBV replication, which can exist in human hepatocytes for a long time and is difficult to be completely removed. It has been shown that HBV RNA can directly respond to the levels and transcriptional activity of cccDNA in hepatocytes and can be used as a surrogate marker of cccDNA transcriptional activity. At present, the detection techniques used for quantitative HBV RNA mainly include reverse transcription quantitative polymerase chain reaction (RT-qPCR) and simultaneous amplification and testing (SAT).

METHODS

In this study, we verified the performance of the SAT method for detecting HBV RNA and the clinical effectiveness of SAT and RT-qPCR, and compared the correlation and consistency of the two detection methods for HBV RNA detection.

RESULTS

The results showed that the limit of detection for HBV RNA by SAT method was 50 copies/mL, with a linear range of 1 × 102-1 × 108 copies/mL. There was no difference in HBV RNA levels detected by the two methods. The correlation and consistency of the results were good, with the coefficient of determination of 0.7787 in HBeAg positive group and 0.8235 in HBeAg negative group.

CONCLUSIONS

Therefore, this study confirmed that the SAT method and RT-qPCR for detecting HBV RNA have good agreement, which are both reliable methods to detect HBV RNA and can replace each other.

Current and novel modalities for management of chronic hepatitis B infection

Over 296 million people are estimated to have chronic hepatitis B viral infection (CHB), and it poses unique challenges for elimination. CHB is the result of hepatitis B virus (HBV)-specific immune tolerance and the presence of covalently closed circular DNA as mini chromosome inside the nucleus and the integrated HBV. Serum hepatitis B core-related antigen is the best surrogate marker for intrahepatic covalently closed circular DNA. Functional HBV “cure” is the durable loss of hepatitis B surface antigen (HBsAg), with or without HBsAg seroconversion and undetectable serum HBV DNA after completing a course of treatment. The currently approved therapies are nucleos(t)ide analogues, interferon-alpha, and pegylated-interferon. With these therapies, functional cure can be achieved in < 10% of CHB patients. Any variation to HBV or the host immune system that disrupts the interaction between them can lead to reactivation of HBV. Novel therapies may allow efficient control of CHB. They include direct acting antivirals and immunomodulators. Reduction of the viral antigen load is a crucial factor for success of immune-based therapies. Immunomodulatory therapy may lead to modulation of the host immune system. It may enhance/restore innate immunity against HBV (as toll-like-receptors and cytosolic retinoic acid inducible gene I agonist). Others may induce adaptive immunity as checkpoint inhibitors, therapeutic HBV vaccines including protein (HBsAg/preS and hepatitis B core antigen), monoclonal or bispecific antibodies and genetically engineered T cells to generate chimeric antigen receptor-T or T-cell receptor-T cells and HBV-specific T cells to restore T cell function to efficiently clear HBV. Combined therapy may successfully overcome immune tolerance and lead to HBV control and cure. Immunotherapeutic approaches carry the risk of overshooting immune responses causing uncontrolled liver damage. The safety of any new curative therapies should be measured in relation to the excellent safety of currently approved nucleos(t)ide analogues. Development of novel antiviral and immune modulatory therapies should be associated with new diagnostic assays used to evaluate the effectiveness or to predict response.

HIV-HBV Coinfection-Current Challenges for Virologic Monitoring

HIV-HBV coinfected patients have higher rates of liver-related morbidity, hospitalizations, and mortality compared to HBV or HIV mono-infected ones. Clinical studies have shown an accelerated progression of liver fibrosis and an increased incidence of HCC, resulting from the combined action of HBV replication, immune-mediated hepatocytolysis, and HIV-induced immunosuppression and immunosenescence. Antiviral therapy based on dually active antiretrovirals is highly efficient, but late initiation, global disparities in accessibility, suboptimal regimens, and adherence issues may limit its impact on the development of end-stage liver disease. In this paper, we review the mechanisms of liver injuries in HIV-HBV coinfected patients and the novel biomarkers that can be used for treatment monitoring in HIV-HBV coinfected persons: markers that assess viral suppression, markers for liver fibrosis evaluation, and predictors of oncogenesis.

Sera of Individuals Chronically Infected with Hepatitis B Virus (HBV) Contain Diverse RNA Types Produced by HBV Replication or Derived from Integrated HBV DNA

This study aimed to better characterize the repertoire of serum hepatitis B virus (HBV) RNAs during chronic HBV infection in humans, which remains understudied. Using reverse transcription-PCR (RT-PCR), real-time quantitative PCR (RT-qPCR), RNA-sequencing, and immunoprecipitation, we found that (i) >50% of serum samples bore different amounts of HBV replication-derived RNAs (rd-RNAs); (ii) a few samples contained RNAs transcribed from integrated HBV DNA, including 5'-HBV-human-3' RNAs (integrant-derived RNAs [id-RNAs]) and 5'-human-HBV-3' transcripts, as a minority of serum HBV RNAs; (iii) spliced HBV RNAs were abundant in <50% of analyzed samples; (iv) most serum rd-RNAs were polyadenylated via conventional HBV polyadenylation signal; (v) pregenomic RNA (pgRNA) was the major component of the pool of serum RNAs; (vi) the area of HBV positions 1531 to 1739 had very high RNA read coverage and thus should be used as a target for detecting serum HBV RNAs; (vii) the vast majority of rd-RNAs and pgRNA were associated with HBV virions but not with unenveloped capsids, exosomes, classic microvesicles, or apoptotic vesicles and bodies; (viii) considerable rd-RNAs presence in the circulating immune complexes was found in a few samples; and (ix) serum relaxed circular DNA (rcDNA) and rd-RNAs should be quantified simultaneously to evaluate HBV replication status and efficacy of anti-HBV therapy with nucleos(t)ide analogs. In summary, sera contain various HBV RNA types of different origin, which are likely secreted via different mechanisms. In addition, since we previously showed that id-RNAs were abundant or predominant HBV RNAs in many of liver and hepatocellular carcinoma tissues as compared to rd-RNAs, there is likely a mechanism favoring the egress of replication-derived RNAs. IMPORTANCE The presence of integrant-derived RNAs (id-RNAs) and 5'-human-HBV-3' transcripts derived from integrated hepatitis B virus (HBV) DNA in sera was demonstrated for the first time. Thus, sera of individuals chronically infected with HBV contained both replication-derived and integrant-transcribed HBV RNAs. The majority of serum HBV RNAs were the transcripts produced by HBV genome replication, which were associated with HBV virions and not with other types of extracellular vesicles. These and other above-mentioned findings advanced our understanding of the HBV life cycle. In addition, the study suggested a promising target area on the HBV genome to increase sensitivity of the detection of serum HBV RNAs and supported the idea that simultaneous detection of replication-derived RNAs (rd-RNAs) and relaxed circular DNA (rcDNA) in serum provides more adequate evaluation of (i) the HBV genome replication status and (ii) the durability and efficiency of the therapy with anti-HBV nucleos(t)ide analogs, which could be useful for improvement of the diagnostics and treatment of HBV-infected individuals.

Hepatitis B virus pre-genomic RNA and hepatitis B core-related antigen reductions at week 4 predict favourable hepatitis B surface antigen response upon long-term nucleos(t)ide analogue in chronic hepatitis B

BACKGROUND/AIMS

We investigated the dynamics of serum HBV pre-genomic RNA (pgRNA) and hepatitis B core-related antigen (HBcrAg) in patients receiving nucleos(t)ide analogues (NAs) and their predictability for favourable suppression of serum hepatitis B surface antigen (HBsAg).

METHODS

Serum viral biomarkers were measured at baseline, weeks 4, 12, 24, 36, and 48 of treatment. Patients were followed up thereafter and serum HBsAg level was measured at end of follow-up (EOFU). Favourable HBsAg response (FHR) was defined as ≤100 IU/mL or HBsAg seroclearance upon EOFU.

RESULTS

Twenty-eight hepatitis B e antigen (HBeAg)-positive and 36 HBeAg-negative patients (median, 38.2 years old; 71.9% male) were recruited with median follow-up duration of 17.1 years (interquartile range, 12.8-18.2). For the entire cohort, 22/64 (34.4%) achieved FHR. For HBeAg-positive patients, serum HBV pgRNA decline at week 4 was significantly greater for patients with FHR compared to non-FHR (5.49 vs. 4.32 log copies/mL, respectively; P=0.016). The area under the receiver-operating-characteristic curve (AUROC) for week 4 HBV pgRNA reduction to predict FHR in HBeAg-positive patients was 0.825 (95% confidence interval [CI], 0.661-0.989). For HBeAg-negative patients, instead of increase in serum HBcrAg in non-FHR patients, FHR patients had median reduction in HBcrAg at week 4 (increment of 1.75 vs. reduction of 2.98 log U/mL; P=0.023). The AUROC for week 4 change of HBcrAg to predict FHR in HBeAg-negative patients was 0.789 (95% CI, 0.596-0.982).

CONCLUSION

Early on-treatment changes of serum HBV pgRNA and HBcrAg at 4 weeks predict HBsAg seroclearance or ≤100 IU/mL in NA-treated CHB patients upon long-term FU.

Clinical study of ganshuang granule combined with tenofovir in the treatment of chronic hepatitis B complicated with nonalcoholic fatty liver disease

Objective: This study aims to investigate the clinical efficacy of Ganshuang granules combined with tenofovir, an antiviral drug, in the treatment of chronic hepatitis B complicated with nonalcoholic fatty liver disease. Methods: A total of 92 patients with chronic hepatitis B combined with non-alcoholic fatty liver who were treated in our Hospital from January 2020 to December 2021 were included as the research objects. According to the method of random number table, the patients were divided into the control group (n = 42) and the treatment group (n = 50). The control group was treated with silibinin meglumine tablets and tenofovir, while the treatment group was treated with Ganshuang granules combined with silybin meglumine tablets and tenofovir. Before and after treatment, liver function index, liver hardness measurement (LSM), controlled attenuation parameter (CAP), HBV-DNA serum load and body mass index (BMI) were observed. Results: Compared with the baseline, ALT, AST and GGT were significantly improved in both groups after treatment (p < 0.05), while TBIL indexes were not significantly different before and after treatment (p > 0.05). Patients in the treatment group had significantly lower ALT and AST index values than the control group at 12 and 24 weeks of treatment (p < 0.05). At 12 and 24 weeks of treatment, the fat attenuation parameters of the two groups were significantly decreased compared with those before treatment, and the difference was statistically significant (p < 0.05). The fat attenuation parameters in the treatment group were significantly lower than those in the control group at 12 and 24 weeks after treatment (p < 0.05). Conclusion: The effect of Ganshuang granule combined with antiviral drugs in the treatment of chronic hepatitis B complicated with non-alcoholic fatty liver is significantly better than that of antiviral drugs alone, which is worthy of clinical recommendation. Systematic Review Registration: https://register.clinicaltrials.gov, identifier NCT05523648.

Levels of HBV RNA in chronic HBV infected patients during first-line nucleos(t)ide analogues therapy

BACKGROUND

Serum HBV RNA has been considered a potential biomarker in monitoring the prognosis of chronic hepatitis B (CHB). However, Real-life cohort studies on the profile of HBV RNA in chronic HBV infected patients during first-line nucleos(t)ide analogues (NAs) are lacking. We aimed to investigate HBV RNA dynamic pattern and clinical value chronic HBV infected patients under NA therapy.

METHODS

HBV RNA and clinical assessments were measured in 82 treatment-naïve chronic HBV infected patients. These enrolled patients were categorized into HBeAg-positive chronic HBV infected (n = 53) and HBeAg-negative chronic HBV infected (n = 29). Of these, there were 59, 46, and 30 chronic HBV infected patients completed the follow-up clinical assessments at 12, 24, and 48 weeks of NAs therapy, respectively.

RESULTS

In treatment-naïve patients, there was a positive correlation between HBV RNA and HBV DNA, HBsAg (r = 0.602 and 0.502. P < 0.05). The median level of HBV DNA was higher than HBV RNA by 1.64 log₁₀ copies/mL_. The mean level of serum HBV RNA was 4.62 (IQR: 3.05-5.82) log₁₀ copies/mL at baseline, and the median level of HBV RNA was 2.88 (IQR: 0-4.67), 2.71 (IQR: 0-4.22), and 2.96 (IQR: 0-4.32) log₁₀ copies/mL at week 12, 24, and 48, respectively. HBV RNA showed a positive linear correlation with HBV DNA at 12, 24, and 48 weeks of NA treatment (r = 0.640, 0.715, and 0.656 respectively, P < 0.05). In patients who were treated 48 weeks NAs, 67% had quantifiable HBV RNA while only 37% had quantifiable HBV DNA.

CONCLUSION

HBV RNA has signature profiles in different stages of chronic HBV infected patients receiving first-line NAs. During antiviral treatment, HBV RNA can still monitor the virus activity in patients whose serum HBV DNA cannot be detected.

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.

Clinical significance of novel biomarkers to predict the natural course of hepatitis B infection

Background and aim

Chronic hepatitis B (CHB) can be divided into immune tolerance (IT), immune clearance (IC), hepatitis B e antigen (HBeAg)-negative inactive/quiescent carrier (ENQ), and HBeAg-negative hepatitis (ENH) phases. The conventional biomarkers used to distinguish these phases have limitations. We examined the clinical significance of hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) as novel biomarkers.

Methods

One hundred eighty-nine patients without treatment currently were categorized by CHB phase (IT = 46, IC = 45, ENQ = 49, ENH = 49). The associations of HBV RNA and HBcrAg with HBV DNA and alanine transaminase (ALT) were analyzed. The decision tree model was used to distinguish the four phases in the natural course of CHB.

Results

The concentrations of HBV RNA and HBcrAg were highest in the IT and IC phases (P < 0.01). Serum HBV RNA was similar to HBcrAg in treatment-naïve patients. HBV RNA and HBcrAg correlated with HBV DNA in the HBeAg⁺ and HBeAg^- status (HBV RNA: e⁺ r = 0.51, e^- r = 0.62; HBcrAg: e⁺ r = 0.51, e^- r = 0.71), but their association with HBV DNA differed among phases. The accuracy, sensitivity, and specificity of HBcrAg with ALT in distinguishing the CHB phases were 95.65%, 95.83%, and 95.55%, respectively.

Conclusion

Serum HBV RNA and HBcrAg may be useful to monitor CHB progression.

The Prognostic Value of Serum HBV-RNA during Hepatitis B Virus Infection is Related to Acute-on-Chronic Liver Failure

BACKGROUND

Serum HBV-RNA levels can predict antiviral response in chronic hepatitis B (CHB) patients; however, its role in HBV-related ACLF (HBV-ACLF) remains unclear. Here, we determined its implications for HBV-ACLF.

METHODS

Baseline serum HBV-RNA levels were retrospectively detected in HBV-ACLF and CHB patients. The association of serum HBV-RNA level with clinical outcomes was evaluated by performing multiple logistic regression. A nomogram was developed to formulate an algorithm incorporating serum HBV-RNA for predicting the survival of HBV-ACLF patients. After being discharged from the hospital, the HBV-ACLF patients were followed up for 36 weeks.

RESULTS

In this study, 82 HBV-ACLF patients and 33 CHB patients were included. Serum HBV-RNA levels were significantly higher in CHB patients than in HBV-ACLF patients (4.15 ± 2.63 log10 copies/mL VS 5.37 ± 2.02 log10 copies/mL) (P < 0.05). Among the HBV-ACLF cases, patients with poor outcomes had lower serum HBV-RNA levels, but the difference was not significant. The area under the receiver operating characteristic curve of the serum HBV-RNA inclusive model was 0.745, superior to 0.66 from MELD scores (P < 0.05). During the follow-up for four weeks, the serum HBV-RNA levels, especially in the survival group, were found to be lower than the baseline levels.

CONCLUSIONS

Serum HBV-RNA levels were associated with disease severity and might predict the long-term clinical outcome of HBV-ACLF patients.

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.

Diversity of the nucleic acid forms of circulating HBV in chronically infected patients and its impact on viral cycle

BACKGROUND

Besides the prototypical hepatitis B virus (HBV) infectious particle, which contains a full-length double-stranded DNA (flDNA), additional circulating virus-like particles, which carry pregenomic RNA (pgRNA), spliced1RNA (sp1RNA) or spliced-derived DNA (defDNA) forms have been described. We aimed to determine the level of these four circulating forms in patients and to evaluate their impact on viral lifecycle.

METHODS

Chronic HBV untreated patients (n = 162), included in the HEPATHER cohort, were investigated. Pangenomic qPCRs were set up to quantify the four circulating forms of HBV nucleic acids (HBV_naf). In vitro infection assays were performed to address the impact of HBV_naf.

RESULTS

Hierarchical clustering individualized two clusters of HBV_naf diversity among patients: (1) cluster 1 (C1) showing a predominance of flDNA; (2) cluster 2 (C2) showing various proportions of the different forms. HBeAg-positive chronic hepatitis phase and higher viral load (7.0 ± 6.4 vs 6.6 ± 6.2 Log₁₀ copies/ml; p < 0.001) characterized C2 compared to C1 patients. Among the different HBV_naf, pgRNA was more prevalent in C1 patients with high vs low HBV viral load (22.1% ± 2.5% vs 4.1% ± 1.8% of HBV_naf, p < 0.0001) but remained highly prevalent in C2 patients, whatever the level of replication. C2 patients samples used in infection assays showed that: (1) HBV_naf secretion was independent of the viral strain; (2) the viral cycle efficiency differed according to the proportion of HBV_naf in the inoculum, independently of cccDNA formation. Inoculum enrichment before infection suggests that pgRNA-containing particles drive this impact on viral replication.

CONCLUSION

Besides the critical role of HBV replication in circulating HBV_naf diversity, our data highlight an impact of this diversity on the dynamics of viral cycle.

CLINICAL TRIAL REGISTRATION

Patients were included from a prospective multicenter French national cohort (ANRS CO22 HEPATHER, NCT01953458).

HBV pgRNA profiles in Chinese HIV/HBV coinfected patients under pre- and posttreatment: a multicentre observational cohort study

Data on hepatitis B virus (HBV) pregenomic (pgRNA) levels in HIV/HBV coinfected patients pre- and post-combined antiretroviral therapy (cART) are limited. This study aimed to evaluate the distribution of HBV pgRNA levels in treatment-naive coinfected patients and explore the changes that occur after the initiation of cART by examining patients from multicentre cohort studies performed in China. We included HIV/HBV coinfected subjects from the China AIDS Clinical Trial cohorts established from 2008 to 2014. Clinical and serological markers of HIV and HBV infection and biochemical data were acquired at baseline and after 96 and 240-480 weeks of cART. The correlations between HBV pgRNA and HBV DNA levels as well as HBsAg levels were calculated using Spearman's bivariate correlation analysis, and multivariate regression analysis was performed to determine factors associated with undetectable HBV pgRNA levels before cART and HBeAg loss after cART. A total of 132 HIV/HBV coinfected patients were enrolled, and 100 individuals were HBeAg-negative. A total of 34.4% (32/93) of patients were positive for HBV pgRNA, and the median HBV pgRNA level was 4.92 (IQR: 4.21-6.12) log₁₀ copies/mL before cART. The median HBV pgRNA level was significantly lower in HBeAg-negative individuals than in HBeAg-positive individuals (4.22 (IQR: 2.70-4.84) log₁₀ copies/mL vs. 5.77 (IQR: 4.63-6.55) log₁₀ copies/mL, p = 0.002). HBV pgRNA was moderately correlated with HBsAg (r = 0.594, p = 0.001), and positively associated with HBV DNA (r = 0.445, p = 0.011). The factors independently associated with undetectable HBV pgRNA level before cART were HBV DNA (OR: 5.61, 95% CI: 1.50-20.96, p = 0.01) and HBeAg status (OR: 5.95, 95% CI: 1.52-23.25, p = 0.01). A total of 87.5% (28/32) of patients were followed for a median duration of 138 (IQR: 54-240) weeks, and the HBV pgRNA levels became undetectable in seven patients. The 132 patients were observed for 695.5 person-years, and no HBsAg loss occurred. Thirteen individuals achieved HBeAg loss, four patients had undetectable levels of HBV pgRNA pre-cART, and the level of six individuals became undetectable during the 48-week (IQR: 48-264) follow-up period. HBeAg status was significantly associated with HBV pgRNA level in HIV/HBV coinfected patients pre- and post-cART. Additionally, undetectable HBV pgRNA level may be associated with HBeAg loss after cART.

A Study on Pregenomic RNA and Factors Related to Hepatitis B Virus Infection Based on Real World

Objective

This article aims to study the influencing factors of pgRNA and its change magnitude based on the real world.

Methods

A total of 421 patients who were tested for pgRNA were selected. According to the baseline data, the subjects were divided into negative and positive groups. The Chi-square test and logistic regression were used to analyze the influencing factors of pgRNA status. Based on the follow-up data, the rank-sum test and linear regression were used to analyze the influencing factors of pgRNA change magnitude.

Results

A total of 153 (36.3%) of the 421 subjects were pgRNA-negative and 268 (63.7%) were pgRNA-positive. Logistic regression analysis showed that positive HBV DNA (OR: 40.51), positive HBeAg (OR: 66.24), tenofovir treatment (OR: 23.47), and entecavir treatment (OR: 14.90) were the independent risk factors for positive pgRNA. Univariate linear regression showed that the pgRNA change magnitude of patients treated with entecavir was higher than that of patients treated with tenofovir. Multivariate linear regression showed that age was an independent factor influencing pgRNA change magnitude.

Conclusions

The pgRNA of patients who were young, female, HBV DNA-positive, high-HBsAg, HBeAg-positive is higher than the detection line. HBV DNA and HBeAg are the independent risk factors of positive pgRNA. Different antiviral regimens and disease stages have significantly different effects on pgRNA status. There was a significant correlation between pgRNA and FIB-4, suggesting that pgRNA is related to liver fibrosis. The decrease in pgRNA was greater in young patients than in non-young patients. The decrease in pgRNA was greater in patients treated with tenofovir than in patients treated with entecavir.

Standardized Hepatitis B Virus RNA Quantification in Untreated and Treated Chronic Patients: a Promising Marker of Infection Follow-Up

The measurement and interpretation of HBV DNA and RNA levels in HBV infected patients treated with antiviral therapy supports the objective of HBV disease management. Here, we quantified circulating HBV RNA through a standardized and sensitive assay in follow-up samples from both naive and treated patients as a marker of infection evolution. HBV DNA (HBV DNA for use in Cobas 6800/8800 Automated Roche Molecular Systems), RNA (Roche HBV RNA Investigational Assay for use in the Cobas 6800/8800; Roche), HBeAg and HBsAg (Elycsys HBsAg chemiluminescence immunoassay by Cobas 8000; Roche), and core-related antigen (Lumipulse G chemiluminescence assay; Fujirebio) levels were measured in cohorts of untreated or nucleos(t)ide treated, HBV-infected subjects in an outpatient hospital setting. HBV DNA levels in untreated people were 3.6 log10 higher than corresponding RNA levels and were stable over 5 years of observation. While only five of 52 treated patients had DNA levels below the lower limit of quantification (10 IU/mL) at the end of follow-up, 13 had HBV RNA levels persistently above this limit, including eight with undetectable DNA. In samples with undetectable core-related antigen we observed a median HBsAg titer 2.7-fold higher than in samples with undetectable RNA (adjusted P = 0.012). Detectable HBV RNA with undetectable HBV DNA was a negative predictor of HBsAg decrease to a level ≤100 IU/mL (P = 0.03). In naive patients the difference between HBV DNA and RNA was higher than previously reported. HBV RNA rapidly decreased during treatment. However, in some cases, it was detectable even after years of effective therapy, being a negative predictor of HBsAg decrease. The investigational RNA assay for use on the Cobas 6800/8800 instruments is a sensitive and standardized method that could be applied in general management of HBV infection. IMPORTANCE This study focused on the quantification of circulating HBV RNA by using a standardized and sensitive assay. Thanks to this system we observed a higher difference between circulating HBV DNA and RNA than previously reported. In treated patients, HBV RNA decreased together with DNA, although some patients presented detectable levels even after years of successful antiviral treatment, suggesting a persistent viral transcription. Of note, the detection of viral RNA when HBV DNA is undetectable was a negative predictor of HBsAg decrease to a level ≤100 IU/mL. This assay could be extremely helpful in HBV patients management to study viral transcription and to identify those treated patients that may achieve sustained viral suppression.

Inhibition of Viral Replication Reduces Transcriptionally Active Distinct Hepatitis B Virus Integrations With Implications on Host Gene Dysregulation

BACKGROUND & AIMS

Hepatocellular carcinogenesis of hepatitis B virus (HBV) infection may arise from integration of viral DNA into the host genome. We aimed to gauge the effect of viral inhibition on transcriptionally active HBV-host integration events and explore the correlation of viral integrations with host gene dysregulation.

METHODS

We leveraged data and biospecimens from an interventional trial, in which patients with HBV viremia above 2000 IU/mL and minimally raised serum liver enzyme were randomized to receive tenofovir disoproxil fumarate (TDF) or placebo for 3 years. Total RNA-sequencing was performed on paired liver biopsies taken before and after the 3-year intervention in 119 patients. Virus-host chimeric reads were captured to quantify the number of distinct viral integrations. Dysregulation of a host gene disrupted by viral integration was defined by aberrant expression >2 standard deviations away from samples without viral integration.

RESULTS

The TDF (n = 64) and placebo groups (n = 55) were comparable at baseline. Expressed viral integrations were detected in all pre- and posttreatment samples. The number of distinct viral integrations significantly correlated with circulatory biomarkers indicative of viral activities including HBV DNA, RNA, and viral antigens (P < .0003 for all correlations). Moreover, TDF vs placebo achieved a significantly greater reduction in distinct viral integrations, with 3.28-fold and 1.81-fold decreases in the expressed integrations per million reads, respectively (analysis of covariance, P = .037). Besides, viral integrations significantly correlated with host gene dysregulation.

CONCLUSION

Inhibition of viral replication reduces the number of transcriptionally active distinct HBV-host DNA integrations in patients with substantial viremia. Given the mutagenic potentials of viral integrations, such treatment effects should be considered in patient management.

Dynamics of Serum Pregenome RNA in Chronic Hepatitis B Patients Receiving 96-Month Nucleos(t)ide Analog Therapy

Background

Tissue covalently closed circular DNA (cccDNA) can reflect the activity of HBV replication. However, it is impractical to assess intrahepatic cccDNA in every outpatient. Serum pregenome RNA (pgRNA) is transcribed from intrahepatic cccDNA and may reflect the activity of intrahepatic cccDNA. We explored the dynamics and the potential role of serum pgRNA in patients receiving long-term NAs treatment.

Methods

Serum pgRNA, HBV DNA, HBsAg, HBeAg, and ALT levels were quantified, and the relationships between serum pgRNA and these common clinical indicators before and after the treatment were investigated.

Results

Serum pgRNA showed dynamic change during the 96-month NAs therapy, and serum pgRNA levels were positive and detectable in 19 patients with undetectable serum HBV DNA. Serum pgRNA showed strong and positive correlation with serum HBV DNA (r = 0.693, p < 0.001) and serum HBsAg levels (r = 0.621, p < 0.001) at baseline. Patients with HBeAg seroconversion had lower baseline serum pgRNA levels (p = 0.002). The area under the curve (AUC) of baseline serum pgRNA for predicting HBeAg seroconversion was 0.742 (95% CI: 0.606–0.850) with 63.16% sensitivity and 80.56% specificity. The cumulative HBeAg seroconversion rate was higher in patients with low serum pgRNA (p = 0.001).

Conclusion

Serum pgRNA of low level at baseline or great decline at month 6 may independently predict the high incidence of undetectable serum pgRNA at year 4 following NAs therapy, and the baseline serum pgRNA may serve as a novel predictor for HBeAg seroconversion during NAs therapy.

Serum hepatitis B virus RNA detectability, composition and clinical significance in patients with ab initio hepatitis B e antigen negative chronic hepatitis B

Background

Serum hepatitis B virus (HBV) RNA is a surrogate biomarker for intrahepatic covalently closed circular DNA (cccDNA) transcriptional activity and persistence. In this retrospective study, we investigated its presence, levels and composition in ab initio Hepatitis B e antigen (HBeAg) negative chronically infected patients and examined possible associations with disease activity and the outcome of nucleos(t)ide analogue (NA) discontinuation.

Methods

We developed a sensitive real time polymerase chain reaction (RT-PCR) for the specific detection of HBV pregenomic RNA (pgRNA) and precore (preC) mRNA and analyzed 220 serum specimens, 160 under NA treatment, from 116 Greek patients initially negative for HBeAg.

Results

HBV pgRNA was detected in 31% and preC mRNA in 15% of samples, at lower levels representing a small fraction (3.4%) of total core promoter produced transcripts. In the absence of NAs, pgRNA was detected in 57% of samples with median value of 5.19 (2.61–8.35) log₁₀ cp/mL, at lower levels than HBV DNA and correlated significantly with ALT (r = 0.764) and serum HBV DNA (r = 0.906). A wide range of HBV DNA/pgRNA ratio was observed with significant inter- and intra-patient variation. During NA treatment, pgRNA displayed low detectability (22%) and variable levels, median 3.97 (2.30– 8.13) log₁₀ cp/mL, as well as, a significant inverse correlation with the duration of treatment (r = − 0.346, p < 0.01). In 74 events of NA discontinuation, end-of-treatment pgRNA-positive compared to pgRNA-negative cases, experienced more frequently virological (p = 0.016) and clinical (p = 0.011) relapse.

Conclusions

In genotype D ab initio HBeAg negative patients, serum HBV RNA is primarily composed of pgRNA plus a minor fraction of preC mRNA transcripts. Serum pgRNA is associated with disease activity, suggesting lysis of infected hepatocytes as a possible source of serum HBV RNA in untreated patients and in the early phase of NA treatment. During long term NA treatment, detectable serum pgRNA predicts viral rebound and clinical relapse following treatment discontinuation and may thus serve as a marker for the decision of cessation of therapy.

Research progress in hepatitis B virus covalently closed circular DNA

Hepatitis B virus (HBV) infections are a global public health issue. HBV covalently closed circular DNA (cccDNA), the template for the transcription of viral RNAs, is a key factor in the HBV replication cycle. Notably, many host factors involved in HBV cccDNA epigenetic modulation promote the development of hepatocellular carcinoma (HCC). The HBV cccDNA minichromosome is a clinical obstacle that cannot be efficiently eliminated. In this review, we provide an update on the advances in research on HBV cccDNA and further discuss factors affecting the modulation of HBV cccDNA. Hepatitis B virus X protein (HBx) contributes to HBV cccDNA transcription and the development of hepatocarcinogenesis through modulating host epigenetic regulatory factors, thus linking the cccDNA to hepatocarcinogenesis. The measurable serological biomarkers of continued transcription of cccDNA, the effects of anti-HBV drugs on cccDNA, and potential therapeutic strategies targeting cccDNA are discussed in detail. Thus, this review describes new insights into HBV cccDNA mechanisms and therapeutic strategies for cleaning cccDNA, which will benefit patients with liver diseases.

Cross-sectional evaluation of circulating hepatitis B virus RNA and DNA: Different quasispecies?

BACKGROUND

Different forms of pregenomic and other hepatitis B virus (HBV) RNA have been detected in patients’ sera. These circulating HBV-RNAs may be useful for monitoring covalently closed circular DNA activity, and predicting hepatitis B e-antigen seroconversion or viral rebound after nucleos(t)ide analog cessation. Data on serum HBV-RNA quasispecies, however, is scarce. It is therefore important to develop methodologies to thoroughly analyze this quasispecies, ensuring the elimination of any residual HBV-DNA. Studying circulating HBV-RNA quasispecies may facilitate achieving functional cure of HBV infection.

AIM

To establish a next-generation sequencing (NGS) methodology for analyzing serum HBV-RNA and comparing it with DNA quasispecies.

METHODS

Thirteen untreated chronic hepatitis B patients, showing different HBV-genotypes and degrees of severity of liver disease were enrolled in the study and a serum sample with HBV-DNA > 5 Log₁₀ IU/mL and HBV-RNA > 4 Log₁₀ copies/mL was taken from each patient. HBV-RNA was treated with DNAse I to remove any residual DNA, and the region between nucleotides (nt) 1255-1611 was amplified using a 3-nested polymerase chain reaction protocol, and analyzed with NGS. Variability/conservation and complexity was compared between HBV-DNA and RNA quasispecies.

RESULTS

No HBV-DNA contamination was detected in cDNA samples from HBV-RNA quasispecies. HBV quasispecies complexity showed heterogeneous behavior among patients. The Rare Haplotype Load at 1% was greater in DNA than in RNA quasispecies, with no statistically significant differences (P = 0.1641). Regarding conservation, information content was equal in RNA and DNA quasispecies in most nt positions [218/357 (61.06%)]. In 102 of the remaining 139 (73.38%), HBV-RNA showed slightly higher variability. Sliding window analysis identified 4 hyper-conserved sequence fragments in each quasispecies, 3 of them coincided between the 2 quasispecies: nts 1258-1286, 1545-1573 and 1575-1604. The 2 hyper-variable sequence fragments also coincided: nts 1311-1344 and 1461-1485. Sequences between nts 1519-1543 and 1559-1587 were only hyper-conserved in HBV-DNA and RNA, respectively.

CONCLUSION

Our methodology allowed analyzing HBV-RNA quasispecies complexity and conservation without interference from HBV-DNA. Thanks to this, we have been able to compare both quasispecies in the present study.

Comparison of HBV RNA and Hepatitis B Core Related Antigen With Conventional HBV Markers Among Untreated Adults With Chronic Hepatitis B in North America

BACKGROUND AND AIMS

The clinical utility of two biomarkers, hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg), as compared to conventional markers of HBV replication and disease activity, is unclear.

APPROACH AND RESULTS

Untreated participants in the North American Hepatitis B Research Network Adult Cohort Study were categorized by chronic hepatitis B (CHB) phases based on HBsAg and HBeAg status and HBV DNA and alanine aminotransferase (ALT) levels. HBV RNA and HBcrAg were measured (Abbott HBV pgRNA Research Assay and Fujirebio Lumipulse Immunoassay, respectively), and cross-sectional associations with conventional CHB markers were tested. Among 1,409 participants across all CHB phases, median HBV DNA was 3.8 log₁₀ IU/mL and ALT was 34 U/L. HBV RNA was quantifiable in 99% of HBeAg⁺ and 58% of HBeAg^- participants; HBcrAg was quantifiable in 20% of HBeAg⁺ (above linear range in the other 80%) and 51% of HBeAg^- participants. Both markers differed across CHB phases (P < 0.001), with higher levels in the HBeAg⁺ and HBeAg^- immune active phases. HBV RNA and HBcrAg correlated moderately strongly with HBV DNA in both HBeAg⁺ and HBeAg^- phases (HBV RNA: e⁺ ρ = 0.84; e^- ρ = 0.78; HBcrAg: e⁺ ρ = 0.66; e^- ρ = 0.56; P for all, <0.001), but with HBsAg levels among HBeAg⁺ phases only (HBV RNA: e⁺ ρ = 0.71; P < 0.001; e^- ρ = 0.18; P = 0.56; HBcrAg: e⁺ ρ = 0.51; P < 0.001; e^- ρ = 0.27; P < 0.001). Associations of higher HBV RNA and HBcrAg levels with higher ALT, APRI, and Fibrosis-4 levels were consistent in HBeAg^- , but not HBeAg⁺ , phases.

CONCLUSIONS

Despite clear relationships between HBV RNA and HBcrAg levels and CHB phases, these markers have limited additional value in differentiating CHB phases because of their strong association with HBV DNA and, to a lesser extent, with clinical disease indicators.

Approaches to quantifying Hepatitis B Virus covalently closed circular (ccc)DNA

Chronic hepatitis B is a major cause of liver disease worldwide and is currently incurable. Hepatitis B virus (HBV) covalently closed circular (ccc) DNA is a key form of the virus responsible for its persistence and is the transcriptional template for all viral transcripts. The field is focussed on methods to clear HBV cccDNA but this been limited by technical difficulties in its quantification due to: identical sequence to other forms of HBV DNA; low copy number per cell; and high resistance to denaturation by heat, leading to difficulty using polymerase chain reaction or hybridization methods for detection. A number of assays have been developed in order to overcome these hurdles either directly or detecting cccDNA levels indirectly via its transcriptional products. In this review, we summarize the approaches to cccDNA quantification that are currently used, and outline key open questions in the cccDNA biology field which remain to be answered due to the limitations of current methods.

Persistence of Hepatitis B Virus Infection: A Multi-Faceted Player for Hepatocarcinogenesis

Hepatitis B virus (HBV) infection has a multi-dimensional effect on the host, which not only alters the dynamics of immune response but also persists in the hepatocytes to predispose oncogenic factors. The virus exists in multiple forms of which the nuclear localized covalently closed circular DNA (cccDNA) is the most stable and the primary reason for viral persistence even after clearance of surface antigen and viral DNA. The second reason is the existence of pregenomic RNA (pgRNA) containing virion particles. On the other hand, the integration of the viral genome in the host chromosome also leads to persistent production of viral proteins along with the chromosomal instabilities. The interferon treatment or administration of nucleot(s)ide analogs leads to reduction in the viral DNA load, but the pgRNA and surface antigen clearance are a slow process and complete loss of serological HBsAg is rare. The prolonged exposure of immune cells to the viral antigens, particularly HBs antigen, in the blood circulation results in T-cell exhaustion, which disrupts immune clearance of the virus and virus-infected cells. In addition, it predisposes immune-tolerant microenvironment, which facilitates the tumor progression. Thus cccDNA, pgRNA, and HBsAg along with the viral DNA could be the therapeutic targets in the early disease stages that may improve the quality of life of chronic hepatitis B patients by impeding the progression of the disease toward hepatocellular carcinoma.

Quantitative serum HBV markers in predicting phases of natural history of chronic HBV infection

BACKGROUND

Clinical importance of commercially available quantitative HBV markers has not been fully investigated.

OBJECTIVE

To choice and to evaluate clinically valuable HBV markers for predicting phases of natural history with chronic HBV infection.

METHODS

472 naïve patients with chronic HBV infection were enrolled, in which 21 and 220 were confirmed as HBeAg-positive inactive and active hepatitis (EPIH and EPAH), respectively, and 106 and 125 were confirmed as HBeAg-negative inactive and active hepatitis (ENIH and ENAH), respectively. HBsAg, HBcrAg and anti- HBc were measured using chemiluminescent immunoassay, and HBV DNA was measured using PCR-fluorescence probing assay.

RESULTS

There were all statistical differences in medians of HBsAg, anti-HBc, HBcrAg and HBV DNA between EPIH and EPAH and between ENIH and ENAH (all P < 0.01). According to binary logistic stepwise regressions, HBsAg and anti-HBc were preferred variables for predicting EPAH, and HBcrAg and HBV DNA were preferred variables for predicting ENAH. Based on normalization for coefficients of preferred variables entering regression equations, a handy model of MEPAH for predicting EPAH and of MENAH for predicting ENAH was constructed, respectively. Area under receiver operating characteristic curves of MEPAH and MENAH for predicting EPAH and ENAH were 0.882 and 0.931, respectively. With standard of MEPAH ≤ 5.997 and MENAH > 10.535, sensitivity or specificity of which for predicting EPAH and ENAH were about 81.0 % and 87.0 %, respectively.

CONCLUSION

HBsAg and anti-HBc for predicting EPAH and HBcrAg and HBV DNA for predicting ENAH are dependable markers; MEPAH for predicting EPAH and MENAH for predicting ENAH have very good performance.

HBV RNA Profiles in Patients With Chronic Hepatitis B Under Different Disease Phases and Antiviral Therapy

BACKGROUND AND AIMS

Large-scale comprehensive studies on HBV RNA in chronic hepatitis B are lacking. We aimed to study the HBV RNA profile and its correlation with other viral markers in patients with chronic hepatitis B who are treatment-naïve and patients receiving nucleos(t)ide analogues (NA).

APPROACH AND RESULTS

Biomarkers, including HBV RNA and hepatitis B core-related antigen (HBcrAg), were measured in 388 patients. Of these, 246 were treatment-naïve and were categorized into HBeAg-positive chronic infection (n = 41), HBeAg-positive chronic hepatitis (n = 81), HBeAg-negative chronic infection (n = 39), HBeAg-negative chronic hepatitis (n = 66), and HBsAg seroclearance (n = 19). These biomarkers were also measured in 142 patients who were NA-treated receiving tenofovir or entecavir at baseline, week 48, and week 96. The pattern of serum HBV RNA levels mirrored HBV DNA (1-2 logs higher than HBV RNA) and HBcrAg in patients who were treatment-naïve. HBV RNA correlated best with HBcrAg (r = 0.84) and to a lesser extent with HBV DNA (r = 0.737) (both P < 0.001). In patients with HBsAg seroclearance, 15.8% and 15.8% had detectable serum HBV RNA and HBcrAg, respectively. NA treatment reduced serum HBV RNA by 1.46 logs and 1.77 logs at weeks 48 and 96, respectively. At week 96 of NA therapy, only 19.1% patients who were tenofovir-treated and 25.7% patients who were entecavir-treated had unquantifiable HBV RNA (P > 0.05). In patients who were treated and had undetectable HBV DNA, 77.5% and 30% had quantifiable HBV RNA and HBcrAg, respectively.

CONCLUSIONS

HBV RNA showed distinct and corresponding profiles in patients with HBV in different disease phases. HBV RNA and HBcrAg could be used to monitor residual transcriptional activities in patients with HBsAg seroclearance. NA led to reduction of serum HBV RNA. Monitoring of viral activities can still be achieved in patients with undetectable HBV DNA by serum HBV RNA.

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.

Hepatitis B virus RNA decline without concomitant viral antigen decrease is associated with a low probability of sustained response and hepatitis B surface antigen loss

BACKGROUND

Serum hepatitis B virus (HBV) RNA may reflect intrahepatic HBV replication. Novel anti-viral drugs have shown potent HBV RNA decline without concomitant hepatitis B surface antigen (HBsAg) decrease. How this relates to off-treatment response is yet unclear.

AIM

To study the degree of on-treatment viral antigen decline among patients with pronounced HBV RNA decrease in relation to off-treatment sustained response and HBsAg loss.

METHODS

HBV RNA, HBsAg and hepatitis B core-related antigen (HBcrAg) were quantified in patients with chronic hepatitis B who participated in two randomised controlled trials of peginterferon-based therapy. Sustained response (HBV DNA <2000 IU/mL) and/or HBsAg loss were assessed in patients with and without on-treatment HBV RNA response (either >2 log HBV RNA decline or >1 log decline resulting in an undetectable value at on-treatment week 24), stratified by concomitant HBsAg decline (<0.5/0.5-1/>1 log).

RESULTS

We enrolled 279 patients; 176 were hepatitis B e antigen (HBeAg)-positive, and 103 were HBeAg-negative. Sustained response was achieved in 20.4% of patients. At on-treatment week 24, HBV RNA response was associated with higher sustained response rates (27.4% vs 13.0% in non-responders, P =  0.004). However, among patients with an HBV RNA response (n = 135), 56.4% did not experience >0.5 log HBsAg decline. Among HBV RNA responders, sustained response was achieved in 47.6% of those with >1 log HBsAg decline (n = 20/42), vs 16.0% with <0.5 log decline (n = 12/75, P = 0.001). Similar results were obtained with HBcrAg and when response was defined as HBsAg loss.

CONCLUSIONS

In this cohort, many patients with HBV RNA response during peginterferon-based treatment did not experience HBsAg and/or HBcrAg decline. The absence of concomitant decline in these viral antigens was associated with low rates of treatment response and HBsAg loss. Future trials should therefore consider kinetics of combined biomarkers to assess anti-viral efficacy. Trial registration, ClinicalTrials.gov: NCT00114361, NCT00146705.

Clinical implications of serum hepatitis B virus RNA quantitation in untreated chronic hepatitis B virus-infected patients

Serum hepatitis B virus (HBV) RNA quantitation may be useful for managing untreated chronic HBV-infected patients, but its distribution characteristics and relationship to HBV DNA are unclear. A retrospective cohort including 149 untreated HBV-infected patients was divided into four clinical phenotypes: hepatitis B envelope antigen (HBeAg) positive with normal alanine transaminase (ALT; EPNA) or with elevated ALT (EPEA), HBeAg-negative with normal ALT (ENNA) or with elevated ALT (ENEA). Serum HBV RNA levels were quantified by a high-sensitivity real-time fluorescent quantitative PCR method and liver biopsy was performed in those with undetectable serum HBV DNA or RNA. The detectable serum HBV RNA levels (log₁₀ copies/mL) in EPNA, EPEA, ENNA, and ENEA were 6.02±1.48, 6.54±1.27, 2.51±0.78 and 3.54±1.25, respectively. The low level (< 2.0 log₁₀ copies/mL) comprised mainly of ENNA phenotype (76.9%), while the high level (> 6.0 log₁₀ copies/mL) was HBeAg-positive patients (98.1%). Serum HBV RNA level were significantly correlated with serum HBV DNA and HBsAg in HBeAg-positive phenotypes, but a correlation only with HBV DNA was observed in ENEA patients. Serum HBV DNA and RNA were both independent risk factors associated with elevated ALT in HBeAg-negative patients. Seven serum HBV DNA-undetectable but RNA-detectable patients underwent liver biopsy, showing moderate or severe liver inflammation. Varying serum HBV RNA levels can reflect natural disease phases in untreated HBV-infected patients, indicating that this biomarker could reflect liver inflammation in untreated HBeAg-negative patients as successfully as serum HBV DNA. Serum HBV RNA can complement clinical management strategies when serum HBV DNA is undetectable.

Reverse transcriptase droplet digital PCR vs reverse transcriptase quantitative real-time PCR for serum HBV RNA quantification

Serum hepatitis B virus (HBV) RNA is a novel marker reflecting the activity of covalently closed circular DNA. However, the methodology for detecting HBV RNA has been a technical challenge. In this study, the performance of reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for quantifying HBV RNA was compared with that of reverse transcription quantitative real-time PCR (RT-qPCR) in serum samples collected from treatment-naïve patients with different phases of chronic hepatitis B (CHB). A total of 417 serum samples, including 136 HBeAg-positive CHB and 281 HBeAg-negative CHB were examined. HBV RNA levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity and quantitative correlation. The limit of detections of RT-ddPCR and RT-qPCR assays were 102 and 103 copies/mL, respectively. Our results also demonstrated that RT-ddPCR was superior to RT-qPCR in terms of its consistency for quantifying HBV RNA across all concentrations. In the HBeAg-positive group, serum HBV RNA levels based on RT-ddPCR were moderately correlated with HBV DNA (r = 0.591, P < .001) and HBsAg (r = 0.502, P < .001). Among patients with HBeAg-negative CHB, serum HBV RNA levels were moderately correlated with HBV DNA (r = 0.603, P < .001) but had weak correlation with HBsAg (r = 0.203, P = .001). In summary, RT-ddPCR could enhance the sensitivity of serum HBV RNA detection, particularly among the HBeAg-negative group with low viral loads. Thus, RT-ddPCR could serve as an optimal method for HBV RNA quantification in clinical practice.

cccDNA Maintenance in Chronic Hepatitis B - Targeting the Matrix of Viral Replication

Chronic hepatitis B is a numerically important cause of cirrhosis and hepatocellular carcinoma, despite an effective prophylactic vaccine and well-tolerated and effective oral antivirals. Both the incapacity of the immune system to clear hepatitis B virus (HBV) infection and the unique replication strategies adopted by HBV are considered key determinants of HBV chronicity. In this regard, the formation of the HBV DNA minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, is essential not only for the production of all viral proteins but also for HBV persistence even after long-term antiviral therapy. Licensed polymerase inhibitors target the HBV reverse transcriptase activity, control the disease with long-term therapy but fail to eliminate the cccDNA. Consequently, the production of viral RNAs and proteins, including the hepatitis B surface antigen (HBsAg), is not abolished. Novel therapeutic efforts that are in the pipeline for early clinical trials explore novel targets and molecules. Such therapeutic efforts focus on achieving a functional cure, which is defined by the loss of HBsAg and undetectable HBV DNA levels in serum. Since a true cure of HBV infection requires the elimination of the cccDNA from infected cells, comprehension of the mechanisms implicated in cccDNA biogenesis, regulation and stability appears necessary to achieve HBV eradication. In this review, we will summarize the state of knowledge on cccDNA metabolism, focusing on insights suggesting potential weak points of the cccDNA that may be key for the development of therapeutic approaches and design of clinical trials aiming at lowering cccDNA loads and activity.

New Therapeutics for Hepatitis B: The Road to Cure

Chronic hepatitis B virus (HBV) infection impacts an estimated 257-291 million people globally. The current approach to treatment for chronic HBV infection is complex, reflecting a risk:benefit approach driven by the lack of an effective curative regimen. This complexity and the lack of a durable treatment response, necessitating indefinite treatment in the majority of cases, have resulted in low uptake of testing and treatment, particularly in regions where comprehensive primary care is lacking and access to affordable testing and treatment is limited. Multiple targeted therapies are now in early human study with the primary goal to achieve persistent HBV DNA and hepatitis B surface antigen suppression after a finite course of treatment, which is referred to as functional cure. This article summarizes the current therapies for HBV infection and discusses the limitations of these therapies, novel approaches to HBV cure, and therapeutic endpoints of clinical trials aimed to cure hepatitis B.

Editorial: serum HBV RNA biphasic decline in patients with HBeAg-positive chronic hepatitis B treated with nucleos(t)ide analogues

LINKED CONTENT This article is linked to Liu et al papers. To view these articles, visit https://doi.org/10.1111/apt.15890 and https://doi.org/10.1111/apt.15993

Serum HBV RNA Dynamic and Drug Withdrawal Predictor Value in Patients With Chronic HBV Infection on Long-term Nucleos(t)ide Analogue (NA) Therapy

AIMS

This study aimed to investigate the dynamic pattern of serum hepatitis B virus (HBV) RNA in chronic hepatitis B (CHB) patients on long-term nucleos(t)ide analogue (NA) therapy and evaluate predictor value of end-of-treatment (EOT) serum HBV RNA status on drug-withdrawal durability.

METHODS

We carried out a real-life cohort study of 326 CHB patients on NA treatment between February 12, 2016 and February 21, 2018. Thirty of these patients discontinued NA treatment after enrollment, and were included in 2-year off-therapy follow-up. Serum HBV RNA levels were determined using the RNA simultaneous amplification testing method.

RESULTS

Both serum HBV RNA and DNA levels declined significantly in long-term antiviral progress. When the treatment duration was longer than 3 years, the undetectable rates of HBV RNA and DNA were 55.10% and 97.0%, respectively. The serum HBV RNA-negative rate was 39.5%. The cumulative 2-year off-therapy viral and clinical relapse rate was 40.56%; 95% confidence interval (95% CI), 21.51-59.61 and 31.31%; 95% CI, 11.32-51.29 in all patients, respectively. Patients with EOT hepatitis B surface antigen (HBsAg)≤1000 IU/mL plus HBV RNA negativity had a relatively lower cumulative 2-year off-therapy viral relapse rate (23.01%; 95% CI, 0.17-45.99). EOT HBsAg≤1000 IU/mL plus HBV RNA negativity showed obvious superiority for the EOT HBsAg≤1000 IU/mL single in drug withdrawal durability prediction, with better specificity (18.18% vs. 72.73%, P=0.03), and the positive predictive value and negative predictive value were 76.92% and 47.06%, respectively.

CONCLUSIONS

In the long-term antiviral process, both serum HBV RNA and DNA levels declined significantly. EOT serum HBV RNA negativity was not an independent drug withdrawal marker, but can complement the HBsAg titer to monitor drug withdrawal in CHB patients on long-term NA therapy.

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.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference‡

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic HBV treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilising cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase III trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity for the prediction of sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive or negative chronic hepatitis, who are treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with an increase in bilirubin or international normalised ratio should prompt temporary or permanent cessation of an investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase III trials for HDV coinfection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalisation of alanine aminotransferase is considered an intermediate goal. In conclusion, regarding HBV 'functional cure', the primary goal is sustained HBsAg loss with undetectable HBV DNA after completion of treatment and the intermediate goal is sustained undetectable HBV DNA without HBsAg loss after stopping treatment.

Engineering Cellular Biosensors with Customizable Antiviral Responses Targeting Hepatitis B Virus

SynNotch receptor technology is a versatile tool that uses the regulatory notch core portion with an extracellular scFv and an intracellular transcription factor that enables to program customized input and output functions in mammalian cells. In this study, we designed a novel synNotch receptor comprising scFv against HBs antigen linked with an intracellular artificial transcription factor and exploited it for viral sensing and cellular immunotherapy. The synNotch receptor expressing cells sensed HBV particles and membrane-bound HBs antigens and responded by expressing reporter molecules, secNL or GFP. We also programmed these cells to dispense antiviral responses such as type I interferon and anti-HBV neutralizing mouse-human chimeric antibodies. Our data reveal that synNotch receptor signaling works for membrane-bound ligands such as enveloped viral particles and proteins borne on liposomal vesicles. This study establishes the concepts of "engineered immunity" where the synNotch platform is utilized for cellular immunotherapy against viral infections.

Diagnostic Value of Detection of Pregenomic RNA in Sera of Hepatitis B Virus-Infected Patients with Different Clinical Outcomes

Pregenomic RNA (pgRNA) is a direct transcription product of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), and it plays important roles in viral genome amplification and replication. This study was designed to investigate whether serum pgRNA is a strong alternative marker for reflecting HBV cccDNA levels and to analyze the correlation between serum pgRNA, serum HBV DNA, and hepatitis B surface antigen (HBsAg). A total of 400 HBV-infected patients who received nucleos(t)ide analog (NA) therapy with different clinical outcomes were involved in this research. Case groups included asymptomatic hepatitis B virus carrier (ASC), chronic hepatitis B (CHB), liver cirrhosis (LC), and hepatocellular carcinoma (HCC) patients, with 100 patients in each group. The results showed that the levels of HBV pgRNA had significant differences between these 4 groups. Serum pgRNA levels correlated well with serum HBV DNA and HBsAg levels (HBV pgRNA levels versus HBV DNA levels, r = 0.58, P < 0.001; HBV pgRNA levels versus HBsAg levels, r = 0.47, P < 0.001). In addition, we focused on the 108 HBV-infected patients with HBV DNA levels of <500 IU/ml; it was surprising to find that in 17.57% (13/74) of cases, HBV pgRNA could be detected even when the HBV DNA level was below 20 IU/ml. In conclusion, HBV pgRNA levels in serum can be a surrogate marker for intrahepatic HBV cccDNA compared with serum HBV DNA and HBsAg. The detection of serum HBV pgRNA levels may provide a reference for clinical monitoring of cccDNA levels and the selection of appropriate timing for discontinuing antiviral therapy, especially when HBV DNA levels are below the detection limit.

Emerging tools in the changing landscape of chronic hepatitis B management

Introduction: The availability of a preventative vaccine, interferon, and nucleos(t)ide analogs have provided progress in the control of chronic hepatitis B (CHB). Despite this, it remains a major contributor to global morbidity and mortality. Developments in our understanding of the pathogenesis of CHB and the emergence of new therapies are paving the way, as we move toward HBV cure.Areas covered: We performed bibliographical searches of online databases to review the literature regarding conventional disease phases of CHB. We provide the latest evidence challenging the perception of the natural history of CHB, noting that previously considered quiescent disease phases may not represent benign disease states devoid of progression. We explore the use of potential novel immunological and viral tools which should enhance disease stratification and management decisions in the coming years. Finally, we discuss the timing of treatment and how this could be initiated earlier to improve treatment outcomes, preventing sequelae of chronic infection.Expert opinion: The treatment paradigm in CHB is set to change with multiple novel agents in early phase clinical trials with the aim of a functional cure. An improved understanding of disease pathogenesis and the timing of treatment will be critical to the success of new therapies.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic hepatitis B virus (HBV) treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilizing cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase 3 trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss, 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity in predicting sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive and HBeAg-negative chronic hepatitis, treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with increase in bilirubin or INR should prompt temporary or permanent cessation of investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase 3 trials for hepatitis D virus (HDV) co-infection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalization of ALT is considered an intermediate goal. CONCLUSION: For HBV 'functional cure', sustained HBsAg loss with undetectable HBV DNA after completion of treatment is the primary goal and sustained undetectable HBV DNA without HBsAg loss after stopping treatment an intermediate goal.