Spontaneous Seroclearance of Hepatitis B Surface Antigen and Risk of Hepatocellular Carcinoma

Quantitative hepatitis B core antibody and quantitative hepatitis B surface antigen: Novel viral biomarkers for chronic hepatitis B management

The management of hepatitis B virus (HBV) infection now involves regular and appropriate monitoring of viral activity, disease progression, and treatment response. Traditional HBV infection biomarkers are limited in their ability to predict clinical outcomes or therapeutic effectiveness. Quantitation of HBV core antibodies (qAnti-HBc) is a novel non-invasive biomarker that may help with a variety of diagnostic issues. It was shown to correlate strongly with infection stages, hepatic inflammation and fibrosis, chronic infection exacerbations, and the presence of occult infection. Furthermore, qAnti-HBc levels were shown to be predictive of spontaneous or treatment-induced HBeAg and HBsAg seroclearance, relapse after medication termination, re-infection following liver transplantation, and viral reactivation in the presence of immunosuppression. qAnti-HBc, on the other hand, cannot be relied on as a single diagnostic test to address all problems, and its diagnostic and prognostic potential may be greatly increased when paired with qHBsAg. Commercial qAnti-HBc diagnostic kits are currently not widely available. Because many methodologies are only semi-quantitative, comparing data from various studies and defining universal cut-off values remains difficult. This review focuses on the clinical utility of qAnti-HBc and qHBsAg in chronic hepatitis B management.

A Dual-domain Engineered Antibody for Efficient HBV Suppression and Immune Responses Restoration

Chronic hepatitis B (CHB) remains a major public health concern because of the inefficiency of currently approved therapies in clearing the hepatitis B surface antigen (HBsAg). Antibody-based regimens have demonstrated potency regarding virus neutralization and HBsAg clearance. However, high dosages or frequent dosing are required for virologic control. In this study, a dual-domain-engineered anti-hepatitis B virus (HBV) therapeutic antibody 73-DY is developed that exhibits significantly improved efficacy regarding both serum and intrahepatic viral clearance. In HBV-tolerant mice, administration of a single dose of 73-DY at 2 mg kg-1 is sufficient to reduce serum HBsAg by over 3 log10 IU mL-1 and suppress HBsAg to < 100 IU mL-1 for two weeks, demonstrating a dose-lowering advantage of at least tenfold. Furthermore, 10 mg kg-1 of 73-DY sustainably suppressed serum viral levels to undetectable levels for ≈ 2 weeks. Molecular analyses indicate that the improved efficacy exhibited by 73-DY is attributable to the synergy between fragment antigen binding (Fab) and fragment crystallizable (Fc) engineering, which conferred sustained viral suppression and robust viral eradication, respectively. Long-term immunotherapy with reverse chimeric 73-DY facilitated the restoration of anti-HBV immune responses. This study provides a foundation for the development of next-generation antibody-based CHB therapies.

Review of Related Factors for Persistent Risk of Hepatitis B Virus-Associated Hepatocellular Carcinoma

Chronic hepatitis B virus (HBV) infection is the largest global cause of hepatocellular carcinoma (HCC). Current HBV treatment options include pegylated interferon-alpha and nucleos(t)ide analogues (NAs), which have been shown to be effective in reducing HBV DNA levels to become undetectable. However, the literature has shown that some patients have persistent risk of developing HCC. The mechanism in which this occurs has not been fully elucidated. However, it has been discovered that HBV's covalently closed circular DNA (cccDNA) integrates into the critical HCC driver genes in hepatocytes upon initial infection; additionally, these are not targets of current NA therapies. Some studies suggest that HBV undergoes compartmentalization in peripheral blood mononuclear cells that serve as a sanctuary for replication during antiviral therapy. The aim of this review is to expand on how patients with HBV may develop HCC despite years of HBV viral suppression and carry worse prognosis than treatment-naive HBV patients who develop HCC. Furthermore, HCC recurrence after initial surgical or locoregional treatment in this setting may cause carcinogenic cells to behave more aggressively during treatment. Curative novel therapies which target the life cycle of HBV, modulate host immune response, and inhibit HBV RNA translation are being investigated.

An Ideal Hallmark Closest to Complete Cure of Chronic Hepatitis B Patients: High-sensitivity Quantitative HBsAg Loss

In the era of antiviral therapy, the main goal of treatment has shifted from the persistent inhibition of hepatitis B virus (HBV) replication to the pursuit of serological clearance of HBs surface antigen (HBsAg). Based on the life cycle of HBV, HBsAg originates from covalently closed circular DNA (cccDNA) and integrated HBV DNA, thus reflecting their transcriptional activity. Complete HBsAg loss may mean elimination or persistent inactivity of the HBV genome including cccDNA and integrated HBV DNA. HBsAg loss improves the recovery of abnormal immune function, which in turn, may further promote the clearance of residual viruses. Combined with functional cure and the great improvement of clinical outcomes, the continuous seroclearance of high-sensitivity quantitative HBsAg may represent the complete cure of chronic hepatitis B (CHB). For many other risk factors besides HBV itself, patients with HBsAg loss still need regular monitoring. In this review, we summarized the evolution of CHB treatment, the origin of serum HBsAg, the pattern of HBsAg seroclearance, and the effect of HBsAg loss on immune function and disease outcomes. In addition, we discuss the significance of high-sensitivity HBsAg detection and its possibility as a surrogate of complete cure.

A Dual Coverage Monitoring of the Bile Acids Profile in the Liver-Gut Axis throughout the Whole Inflammation-Cancer Transformation Progressive: Reveal Hepatocellular Carcinoma Pathogenesis

Hepatocellular carcinoma (HCC) is the terminal phase of multiple chronic liver diseases, and evidence supports chronic uncontrollable inflammation being one of the potential mechanisms leading to HCC formation. The dysregulation of bile acid homeostasis in the enterohepatic circulation has become a hot research issue concerning revealing the pathogenesis of the inflammatory-cancerous transformation process. We reproduced the development of HCC through an N-nitrosodiethylamine (DEN)-induced rat model in 20 weeks. We achieved the monitoring of the bile acid profile in the plasma, liver, and intestine during the evolution of "hepatitis-cirrhosis-HCC" by using an ultra-performance liquid chromatography-tandem mass spectrometer for absolute quantification of bile acids. We observed differences in the level of primary and secondary bile acids both in plasma, liver, and intestine when compared to controls, particularly a sustained reduction of intestine taurine-conjugated bile acid level. Moreover, we identified chenodeoxycholic acid, lithocholic acid, ursodeoxycholic acid, and glycolithocholic acid in plasma as biomarkers for early diagnosis of HCC. We also identified bile acid-CoA:amino acid N-acyltransferase (BAAT) by gene set enrichment analysis, which dominates the final step in the synthesis of conjugated bile acids associated with the inflammatory-cancer transformation process. In conclusion, our study provided comprehensive bile acid metabolic fingerprinting in the liver-gut axis during the inflammation-cancer transformation process, laying the foundation for providing a new perspective for the diagnosis, prevention, and treatment of HCC.

Spontaneous Seroclearance Is Associated with Lower Liver Fibrosis in Treatment-Naïve Chronic Hepatitis B Patients

BACKGROUND

Chronic hepatitis B virus (HBV) is a major public health concern. Transient elastrography (TE) is a reliable method in assessing hepatic fibrosis in patients with liver disease. We assess the potential clinical associations between HBsAg seroclearance and the severity of liver fibrosis.

METHODS

We retrospectively performed a matched analysis of 23 consecutive HBsAg seroclearance patients who underwent TE between March 2008 and August 2021 from a community practice at a 1:3 ratio based on clinic visit date. Baseline laboratory and clinical data were collected. Fisher's exact test and Chi-square test for proportions, and Wilcoxon rank-sum test for median were performed.

RESULTS

Twenty-three cases and 69 controls were identified. Median follow up (interquartile range) for the cases and controls was 24,314 (1402) and 2332 (1587) days (p  =  0.15), respectively. All patients were Asian. Median age of cases was higher than controls (64 vs 52, p < 0.01, respectively). While most comorbidities were similar, diabetes and hyperlipidemia were more prevalent in cases. Baseline HBV DNA was detectable in 78% of cases and 97% of controls (p < 0.01). More cases had baseline HBsAg titers below 1000 IU/mL than controls (81% vs 8.7%, p < 0.01). Other baseline laboratory values were similar. Few cases had a fibrosis score greater than 1, while control had over a quarter of patients with a fibrosis score of 2 or 3.

CONCLUSION

Spontaneous HBsAg seroclearance remains rare in patients with chronic HBV infection. It is associated with low baseline HBsAg, and lower level of liver fibrosis as detected by TE.

Toll-Like Receptor 7 Agonist RG7854 Mediates Therapeutic Efficacy and Seroconversion in Woodchucks With Chronic Hepatitis B

Conventional treatment of chronic hepatitis B (CHB) is rarely curative due to the immunotolerant status of patients. RG7854 is an oral double prodrug of a toll-like receptor 7 (TLR7) agonist that is developed for the treatment of CHB. The therapeutic efficacy, host immune response, and safety of RG7854 were evaluated in the woodchuck model of CHB. Monotreatment with the two highest RG7854 doses and combination treatment with the highest RG7854 dose and entecavir (ETV) suppressed viral replication, led to loss of viral antigens, and induced seroconversion in responder woodchucks. Since viral suppression and high-titer antibodies persisted after treatment ended, this suggested that a sustained antiviral response (SVR) was induced by RG7854 in a subset of animals. The SVR rate, however, was comparable between both treatment regimens, suggesting that the addition of ETV did not enhance the therapeutic efficacy of RG7854 although it augmented the proliferation of blood cells in response to viral antigens and magnitude of antibody titers. The induction of interferon-stimulated genes in blood by RG7854/ETV combination treatment demonstrated on-target activation of TLR7. Together with the virus-specific blood cell proliferation and the transient elevations in liver enzymes and inflammation, this suggested that cytokine-mediated non-cytolytic and T-cell mediated cytolytic mechanisms contributed to the SVR, in addition to the virus-neutralizing effects by antibody-producing plasma cells. Both RG7854 regimens were not associated with treatment-limiting adverse effects but accompanied by dose-dependent, transient neutropenia and thrombocytopenia. The study concluded that finite, oral RG7854 treatment can induce a SVR in woodchucks that is based on the retrieval of antiviral innate and adaptive immune responses. This supports future investigation of the TLR7 agonist as an immunotherapeutic approach for achieving functional cure in patients with CHB.

Hepatocellular Carcinoma in Hepatitis B Virus-Infected Patients and the Role of Hepatitis B Surface Antigen (HBsAg)

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer-related death worldwide. Hepatitis B virus (HBV) infection is among the main risk factors for HCC. The risk of HCC is not eliminated completely after viral suppression, due to HBV DNA integrated into human chromosomes. Cirrhosis, HBV viral DNA levels, age, male gender, the immune response of the host against HBV, and a combination of obesity and diabetes are among the main risk factors for HCC. Active viral replication and long-standing active disease with inflammation are associated with a higher risk of HCC. Treatment of HBV with nucleos(t)ide analogues (NAs) decreased HCC risk by effectively decreasing viral load and inflammation. Similar risk factors have been reported in hepatitis B patients after seroclearance. Studies have reported decreased risk of HCC after seroclearance, but there were also conflicting results from a few studies indicating no difference in risk of developing HCC. The difference in HCC rates could be because of other factors such as coinfection, occult HBV infection, family history, HBV genotype, and other comorbidities. Due to the persistent risk of HCC after seroclearance, HCC surveillance is critical for early detection, especially in high-risk patients. However, long-term studies might be needed to further validate the results.

Systematic review with meta-analysis: the impact of functional cure on clinical outcomes in patients with chronic hepatitis B

BACKGROUND

Although hepatitis B surface antigen (HBsAg) loss is considered the ideal therapeutic endpoint for the treatment of chronic hepatitis B virus (HBV) infection, its impact on clinical outcomes remains uncertain.

AIM

To assess the impact of HBsAg loss on clinical outcomes following spontaneous and treatment-related HBsAg loss.

METHODS

We searched PUBMED, Embase, the Cochrane library, and published abstracts through to May 2021 for studies that reported HBsAg loss, had >1 year of follow-up and reported at least one clinical outcome in adults with chronic HBV infection.

RESULTS

We identified 57 studies (258 744 HBsAg-positive patients, 63 270 with HBsAg loss). Based on 24 studies including 160 598 patients with and without HBsAg loss, HBsAg loss was associated with a non-significant 23% relative risk reduction of developing hepatocellular carcinoma (HCC) compared to those who remained HBsAg-positive (RR = 0.77; 95% CI: 0.38-1.57). In subgroup meta-analysis of 10 studies, treatment-related HBsAg loss was associated with a non-significant higher pooled proportion of HCC (0.94%) compared to spontaneous HBsAg loss (0.45%). HCC development after HBsAg loss was significantly higher in males, those with underlying cirrhosis, and those with a family history of HCC. HBsAg loss was associated with lower pooled proportions of incident cirrhosis, hepatic decompensation, overall and liver-related mortality compared to no HBsAg loss. Substantial heterogeneity was noted across studies for all outcomes.

CONCLUSION

HBsAg loss is associated with a reduced risk of clinical outcomes. However, several shortcomings in the published studies prevent a more definitive conclusion on the potential benefits of HBsAg loss.

Efficacy and safety of peginterferon alpha monotherapy in Chinese inactive chronic hepatitis B virus carriers

BACKGROUND & AIMS

The effectiveness and safety of peginterferon alpha (peg-IFN-α) monotherapy in inactive hepatitis B virus (HBV) carriers (IHCs) have not been fully evaluated.

METHODS

This observational study prospectively enrolled 298 IHCs in China from 2015 to 2019. Participants were given the right to choose to either receive peg-IFN-α monotherapy (treatment group, n = 142) or be monitored without treatment (control group, n = 156) according to their wishes. The scheduled treatment duration was 48 weeks. All participants were followed up to 72 weeks. The main efficacy endpoint was hepatitis B surface antigen (HBsAg) clearance at 72 weeks.

RESULTS

Baseline characteristics were similar between both groups. At 72 weeks, intention-to-treat analysis showed that the rates of HBsAg clearance and seroconversion of the treatment group were 47.9% (68/142) and 36.6% (52/142), respectively, which were significantly higher than the HBsAg clearance rate of 1.9% (3/156) and the seroconversion rate of 0.6% (1/156) in the control group (both P < .001). Baseline HBV DNA < 20 IU/mL, lower HBsAg levels at baseline, 12 and 24 weeks, alanine aminotransferase elevation at 12 weeks, and greater HBsAg reduction from baseline to 12 and 24 weeks were independent predictors of HBsAg clearance. Generally, the therapy was well tolerated. Only five participants discontinued therapy as a result of peg-IFNα-related adverse events.

CONCLUSIONS

Peg-IFN-α monotherapy results in high rates of HBsAg clearance and seroconversion and the treatment is safe for IHCs.

Durability of hepatitis B surface antigen seroclearance and subsequent risk for hepatocellular carcinoma: A meta-analysis

Hepatitis B surface antigen (HBsAg) seroclearance is regarded as the ideal endpoint for antiviral treatment. However, reports on the durability of and outcomes after HBsAg seroclearance are few, which has become a focus in clinical practice. This meta-analysis was performed to evaluate the durability and hepatocellular carcinoma (HCC) incidence after HBsAg seroclearance after treatment cessation. We searched PubMed, Embase, Medline and Web of Science for studies that reported the durability and HCC incidence after HBsAg seroclearance published between 1 January 2000 and 31 January 2020. Data were analysed by a random-effects model. Thirty-eight studies and 43,924 patients were finally included. The results showed that HBsAg seroclearance was durable, with a pooled recurrence rate of 6.19% (95% CI: 4.10%-8.68%). There was no significant difference in recurrence rates after different seroclearance methods or among recurrence types and different regions. Anti-HBs seroconversion resulted in a significantly reduced recurrence rate (RR = 0.25, p < .001). Patients who experienced HBsAg seroclearance had significantly lower HCC incidence than HBsAg-positive (RR = 0.41, p < .001). The pooled HCC incidence after HBsAg seroclearance was 1.88%; this rate was reduced to 0.76% among patients without baseline cirrhosis. In conclusion, the analysis during an average follow-up of 4.74 years suggested that in patients who experienced sustained HBsAg seroclearance and anti-HBs seroconversion, this was associated with low HCC incidence. Patients without baseline cirrhosis benefited even more. We emphasize the importance of gaining HBsAg seroclearance while highlighting the benefits of achieving this as early as possible.

Hepatitis B Virus Cure: Targets and Future Therapies

Chronic hepatitis B virus (HBV) infection is a major global health problem. It can cause progressive liver fibrosis leading to cirrhosis with end-stage liver disease, and a markedly increased risk of hepatocellular carcinoma. In the last two decades, substantial progress has been made in the treatment of chronic hepatitis, B. However, HBV is often reactivated after stopping nucloes(t)ide analogues because antivirals alone do not directly target covalently closed circular DNA, which is the template for all viral RNAs. Therefore, although currently available antiviral therapies achieve suppression of HBV replication in the majority of patients, hepatitis B surface antigen (HBsAg) loss and seroconversion is rarely achieved despite long-term antiviral treatment (HBsAg loss of less than 10% in 5 years). Various clinical trials of agents that interrupt the HBV life cycle in hepatocytes have been conducted. Potential treatment strategies and new agents are emerging as HBV cure. A combination of current and new anti-HBV agents may increase the rate of HBsAg seroclearance; thus, optimized regimens must be validated. Here, we review the newly investigated therapeutic compounds and the results of preclinical and/or clinical trials.

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.