Changes in serum hepatitis B surface and e antigen, interferon-inducible protein 10, and aminotransferase levels during combination therapy of immune-tolerant chronic hepatitis B

Neutralizing antibodies to interferon alfa arising during peginterferon therapy of chronic hepatitis B in children and adults: Results from the HBRN Trials

BACKGROUND AIMS

Pegylated interferon-α (PegIFNα) is of limited utility during immunotolerant or immune active phases of chronic hepatitis B infection but is being explored as part of new cure regimens. Low/absent levels of IFNα found in some patients receiving treatment are associated with limited/no virological responses. The study aimed to determine if sera from participants inhibit IFNα activity and/or contain therapy-induced anti-IFNα antibodies.

APPROACH RESULTS

Pre-treatment, on-treatment, and post-treatment sera from 61 immunotolerant trial participants on PegIFNα/entecavir therapy and 88 immune active trial participants on PegIFNα/tenofovir therapy were screened for anti-IFNα antibodies by indirect ELISA. The neutralization capacity of antibodies was measured by preincubation of sera±recombinant human IFNα added to Huh7 cells with the measurement of interferon-stimulated gene (ISG)-induction by qPCR. Correlations between serum-induced ISG inhibition, presence, and titer of anti-IFNα antibodies and virological responses were evaluated. Preincubation of on-treatment serum from 26 immunotolerant (43%) and 13 immune active (15%) participants with recombinant-human IFNα markedly blunted ISG-induction in Huh7 cells. The degree of ISG inhibition correlated with IFNα antibody titer ( p < 0.0001; r = 0.87). On-treatment development of anti-IFNα neutralizing antibodies (nAbs) was associated with reduced quantitative HBsAg and qHBeAg declines ( p < 0.05) and inhibited IFNα bioactivity to 240 weeks after PegIFNα cessation. Children developed anti-IFNα nAbs more frequently than adults ( p = 0.004) but nAbs in children had less impact on virological responses.

CONCLUSIONS

The development of anti-IFNα nAbs during PegIFNα treatment diminishes responses to antiviral therapy. Understanding how and why anti-IFNα antibodies develop may allow for the optimization of IFN-based therapy, which is critical given its renewed use in HBV-cure strategies.

Achieving chronic hepatitis B functional cure: Factors and potential mechanisms

Chronic hepatitis B (CHB) is a significant global health issue affecting approximately 254 million individuals worldwide. Achieving the loss of hepatitis B surface antigen (HBsAg), either with or without seroconversion to hepatitis B surface antibody (HBsAb), is regarded as a functional cure and the optimal goal for addressing CHB, and can be achieved through various approaches, including induction with nucleos(t)ide analogues (NAs), induction with pegylated interferon alpha (PegIFNα), and spontaneous clearance of HBsAg. Spontaneous clearance of HBsAg is rare, while NAs can directly inhibit HBV DNA, they are unable to act on covalently closed circular DNA (cccDNA), hence inhibiting HBsAg production or clearing HBsAg is extremely challenging. On the other hand, functional cure based on PegIFNα shows good long-term durability, but over 10 % of patients still experience relapse, mostly within 48 weeks after functional cure. Factors related to CHB functional cure with antiviral therapy are complex, including host factors, viral factors, environmental factors, etc. The integration of HBV DNA into liver cells, persistence of HBV cccDNA, insufficient B cell responses and compromised T cell function pose significant barriers to HBV clearance. Therefore, this study systematically reviewed the relevant factors and potential mechanisms influencing functional cure CHB, which can provide a basis for personalized treatment, help predict treatment outcomes and assess prognosis, and provide theoretical support for the advancement of novel treatment strategies and medications.

Hepatitis B cure: Current situation and prospects

Achievement of a 'clinical cure' in chronic hepatitis B (CHB) implies sustained virological suppression and immunological control over the infection, which is the ideal treatment goal according to domestic and international CHB management guidelines. Clinical practice has shown encouraging results for specific patient cohorts using tailored treatment regimens. These regimens incorporate either nucleos(t)ide analogs, immunomodulatory agents such as pegylated interferon α, or a strategic combination of both, sequentially or concurrently administered. Despite these advancements in the clinical handling of hepatitis B, achieving a clinical cure remains elusive for a considerable subset of patients due to the number of challenges that preclude the realization of optimal treatment outcomes. These include, but are not limited to, the emergence of antiviral resistance, incomplete immune recovery, and the persistence of covalently closed circular DNA. Moreover, the variance in response to interferon therapy and the lack of definitive biomarkers for treatment cessation also contribute to the complexity of achieving a clinical cure. This article briefly overviews the current research progress and existing issues in pursuing a clinical cure for hepatitis B.

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.

CXCL10 and its receptor in patients with chronic hepatitis B and their ability to predict HBeAg seroconversion during antiviral treatment with TDF

The serum chemokine C-X-C motif ligand-10 (CXCL10) and its unique receptor (CXCR3) may predict the prognosis of patients with chronic hepatitis B (CHB) treated with tenofovir disoproxil fumarate (TDF). Nevertheless, there are few reports on the profile of CXCL10 and CXCR3 and their clinical application in HBeAg (+) CHB patients during TDF antiviral therapy. CXCL10 and CXCR3 were determined in 118 CHB patients naively treated with TDF for at least 96 weeks at baseline and at treatment weeks 12 and 24. In addition, gene set enrichment analysis was used to examine the associated dataset from Gene Expression Omnibus and explore the gene sets associated with HBeAg seroconversion (SC). The change of CXCL10 (ΔCXCL10, baseline to 48-week TDF treatment) and CXCR3 (ΔCXCR3) is closely related to the possibility of HBeAg SC of CHB patients under TDF treatment. Immunohistochemical analysis of CXCL10/CXCR3 protein in liver tissue shows that there is a significant difference between paired liver biopsy samples taken before and after 96 weeks of successful TDF treatment of CHB patients (11 pairs) but no significance for unsuccessful TDF treatment (14 pairs). Multivariate Cox analysis suggests that the ΔCXCL10 is an independent predictive indicator of HBeAg SC, and the area under the receiver operating characteristic curve of the ΔCXCL10 in CHB patients is 0.8867 (p < 0.0001). Our results suggest that a lower descending CXCL10 level is associated with an increased probability of HBeAg SC of CHB patients during TDF therapy. Moreover, liver tissue CXCL10 might be involved in the immunological process of HBeAg SC.

Efficacy and Safety of Antiviral Therapy for Immune-tolerant Hepatitis B Viral Infection in Children: A Systematic Review and Meta-analysis

BACKGROUND

Chronic hepatitis B virus (HBV) infection burden in children remains a pressing public health concern. Whether antiviral therapy should be administered to children with HBV in the immune-tolerant phase remains controversial. We performed a meta-analysis to evaluate antiviral therapy efficacy and safety in children with immune-tolerant hepatitis B (ITHB).

METHODS

A search was conducted in multiple databases (PubMed, Embase, Cochrane, Web of Science, CBM, CNKI and Wanfang Data) to identify clinical trials examining antiviral therapy efficacy and safety in children (1-18 years) with ITHB viral infection from inception to February 2023. Outcomes were calculated separately for controlled and single-arm studies.

RESULTS

Nine trials (442 patients), including 2 randomized controlled trials (RCTs), 3 non-RCTs and 4 single-arm studies, were included in this meta-analysis. In the RCTs, antiviral therapy group exhibited greater rates of HBsAg loss [risk ratio (RR) = 6.11, 95% confidence interval (CI): 1.67-22.31, P Z-test = 0.006], HBsAg serologic response (RR = 5.29, 95% CI: 1.47-19.07, P Z-test = 0.011) and HBeAg loss (RR = 3.00, 95% CI: 1.35-6.66, P Z-test = 0.007) compared with the control group at the end of follow-up. In single-arm studies, the pooled incidences of HBsAg loss, HBeAg loss and HBsAg seroconversion were 24% (95% CI: -0.1% to 48%), 24% (95% CI: -0.1% to 48%) and 24% (95% CI: -5% to 52%), respectively.

CONCLUSION

Current evidence suggests the effectiveness of antiviral therapy in children with HBV infection in the immune-tolerant stage, with few serious adverse events. Due to the limited quality and number of included studies, more high-quality studies are required to validate our findings.

Functional Cure of Chronic Hepatitis B with Antiviral Treatment in Children having High-level Viremia and Normal or Mildly Elevated Serum Aminotransferase

Background and Aims

There is a lack of data supporting the notion that antiviral treatments can benefit children with chronic hepatitis B (CHB) having high viremia and normal or mildly elevated serum alanine aminotransferase (ALT) levels. We aimed to analyze the efficacy of antiviral treatments in children with CHB and explore the factors associated with functional cure.

Methods

Forty-eight children with CHB having high viremia and normal or mildly elevated serum ALT levels were screened in this real-world study. Thirty-two children received either interferon-alpha (IFN-α) monotherapy, IFN-α therapy with a nucleoside analog (NA) add-on, or IFN-α and NA combination therapy. The 16 children in the control group did not receive antiviral treatment. All 48 children were available for follow-up assessments for the entire 36-month study period. We identified a functional cure with respect to hepatitis B virus (HBV) DNA loss, loss /seroconversion of circulating hepatitis B e antigen (HBeAg), and loss of hepatitis B surface antigen (HBsAg) with or without seroconversion. Cox regression analysis was employed to evaluate the factors that may have influenced the functional cure.

Results

After 36 months, the cumulative functional cure rate was 56.25% (18/32) in the treated group and 0% (0/16) in the control group (p<0.001). In the treated group, the serum HBV DNA levels declined rapidly at the end of a 6-month visit and the cured children achieved a loss rate of 100% (18/18) within 16 months of beginning treatment, compared with 64.29% (9/14) of the uncured children (p<0.001). The rates of HBeAg seroconversion were significantly higher among the cured children than among the uncured children (p<0.001). All 16 children in the control group maintained high levels of serum HBV DNA and were positive for both serum HBeAg and HBsAg during the entire 36 months of the study period. Functional cure was associated with younger ages (1-6 vs. 7-14 years, p=0.013), CD8+ T lymphocyte counts (p=0.013), and B lymphocyte counts (p=0.003). No serious adverse events were observed.

Conclusions

Antiviral treatment achieved a functional cure of CHB in a high proportion of children having high-level viremia and normal or mildly elevated ALT levels. Younger age and high peripheral lymphocyte counts were associated with this functional cure.

Advances in Immunotherapy for Hepatitis B

Hepatitis B virus (HBV) is a hepatotropic virus with the potential to cause chronic infection, and it is one of the common causes of liver disease worldwide. Chronic HBV infection leads to liver cirrhosis and, ultimately, hepatocellular carcinoma (HCC). The persistence of covalently closed circular DNA (cccDNA) and the impaired immune response in patients with chronic hepatitis B (CHB) has been studied over the past few decades. Despite advances in the etiology of HBV and the development of potent virus-suppressing regimens, a cure for HBV has not been found. Both the innate and adaptive branches of immunity contribute to viral eradication. However, immune exhaustion and evasion have been demonstrated during CHB infection, although our understanding of the mechanism is still evolving. Recently, the successful use of an antiviral drug for hepatitis C has greatly encouraged the search for a cure for hepatitis B, which likely requires an approach focused on improving the antiviral immune response. In this review, we discuss our current knowledge of the immunopathogenic mechanisms and immunobiology of HBV infection. In addition, we touch upon why the existing therapeutic approaches may not achieve the goal of a functional cure. We also propose how combinations of new drugs, and especially novel immunotherapies, contribute to HBV clearance.