Nested case-control study: hepatocellular carcinoma risk after hepatitis B surface antigen seroclearance

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.

Clinical Consequences of Hepatitis B Surface Antigen Loss in Chronic Hepatitis B Infection: A Systematic Literature Review and Meta-Analysis

Background and Aims

Functional cure, which requires sustained hepatitis B surface antigen (HBsAg) loss after treatment cessation, is currently the optimal treatment endpoint for chronic hepatitis B virus infection. We performed a systematic literature review (SLR) and meta-analyses to assess the association between HBsAg loss and long-term clinical outcomes.

Methods

We performed a SLR of scientific literature published in Medline and Embase reporting the incidence of cirrhosis, hepatic decompensation (HD), hepatocellular carcinoma (HCC), liver-related mortality (LRM), and all-cause mortality (ACM) in relation to HBsAg status. Bayesian hierarchical commensurate prior meta-analyses synthesized evidence on the association between HBsAg loss and each outcome.

Results

Thirty-eight studies, comprising 50,354 patients with 350,734 patient-years of follow-up, were included in the meta-analyses, reporting on cirrhosis (n = 12), HD (n = 12), HCC (n = 36), LRM (n = 12), and ACM (n = 16). Pooled incidence rate ratios (IRRs; vs HBsAg persistence) and respective credible intervals (Crls) were 0.28 (0.060-1.070) for cirrhosis, 0.13 (0.013-0.38) for HD, 0.27 (0.11-0.53) for HCC, 0.17 (0.028-0.61) for LRM, and 0.64 (0.24-1.17) for ACM. Single-predictor-adjusted IRRs remained consistent with those from the primary analyses for all outcomes except cirrhosis and LRM. Outcome incidence rates were modified by selected study, patient and infection characteristics, but trended in the same direction of reduced risk after loss.

Conclusion

Overall, HBsAg loss was associated with a reduced risk of most clinically relevant outcomes. While the magnitude of the effect differed across subgroups, the direction of the association remained similar. Our results validate the need to develop new strategies to achieve HBsAg loss.

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.

Advances in Nanoparticle Drug Delivery Systems for Anti-Hepatitis B Virus Therapy: A Narrative Review

Chronic hepatitis B (CHB) is an infectious viral disease that is prevalent worldwide. Traditional nucleoside analogues, as well as the novel drug targets against hepatitis B virus (HBV), are associated with certain critical factors that influence the curative effect, such as biological stability and safety, effective drug delivery, and controlled release. Nanoparticle drug delivery systems have significant advantages and have provided a basis for the development of anti-HBV strategies. In this review, we aim to review the advances in nanoparticle drug delivery systems for anti-hepatitis B virus therapy by summarizing the relevant literature. First, we focus on the characteristics of nanoparticle drug delivery systems for anti-HBV therapy. Second, we discuss the nanoparticle delivery systems for anti-HBV nucleoside drugs, gene-based drugs, and vaccines. Lastly, we provide an overview of the prospects for nanoparticle-based anti-HBV agents.

Estimated prevalence and number of persons with isolated antibody to hepatitis B core antigen and associated occult hepatitis B, United States, 2001-2018

Persons with isolated antibody to HBV core antigen (IAHBc) may have occult HBV infection (OBI), which is associated with reactivation and potential risk for hepatocellular carcinoma and HBV transmission. We used National Health and Nutrition Examination Survey (NHANES) data to estimate US IAHBc prevalence and published studies of IAHBc-associated OBI prevalence to estimate OBI burden. During 2001-2018, IAHBc prevalence was 0.8% (approximately 2.1 million persons); OBI burden range was 35,500-83,600 persons. These data support the need for more robust estimates of IAHBc-associated OBI prevalence in the general US population.

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.

Systematic review of risk factors of hepatocellular carcinoma after hepatitis B surface antigen seroclearance

There is no consensus about factors that increase risk of hepatocellular carcinoma (HCC) among patients with chronic hepatitis B who have achieved seroclearance of hepatitis B surface antigen (HBsAg). To assess the available evidence about risk factors for HCC after HBsAg seroclearance, Scopus, EMBASE, PubMed and Cochrane Library databases were systematically searched for relevant studies published through 15 September 2017. A total of 28 studies involving more than 105 411 patients with chronic hepatitis B were included. HBsAg seroclearance occurred spontaneously in 7656, while it occurred after interferon or nucleos(t)ide analogue therapy in 1248. The rate of HBsAg seroclearance was 6.77%. Incidence of HCC was significantly lower among patients who experienced HBsAg seroclearance than among those who remained HBsAg-positive (1.86% vs 6.56%, P < .001). Risk factors of HCC occurrence included cirrhosis (incidence with vs without: 9.51% vs 1.66%), male gender (2.34% vs 0.64%) and age ≥ 50 year at HBsAg seroclearance (2.34% vs 0.63%) (all P < .001). The available evidence suggests that HCC can develop at a low rate after HBsAg seroclearance, so periodic surveillance is recommended, especially for male patients, patients with cirrhosis and patients who experience HBsAg seroclearance when at least 50 years old.

Late development of hepatocellular carcinoma after viral clearance in patients with chronic hepatitis C: A need for continual surveillance

OBJECTIVE

Eradication of chronic hepatitis C (CHC) infection decreases the incidence of hepatocellular carcinoma (HCC), but a risk remains. We aimed to investigate HCC development-associated factors in CHC patients with sustained virological response (SVR) after antiviral therapies.

METHODS

We compared CHC patients achieving SVR from 1996-2016 who did and did not develop HCC. Their median follow-up period was 8.01 years.

RESULTS

Compared with 164 non-HCC SVR patients, 22 who developed HCC were older at SVR (P = 0.032), had a higher incidence of diabetes (P = 0.013) and higher pre-antiviral treatment alpha-fetoprotein (AFP) levels (P = 0.016), more had fibrosis stage 3 and cirrhosis (P = 0.0009) and hepatitis B core antibody (anti-HBc) positivity (P = 0.006). Eight and seven of 22 patients, respectively, developed HCC at 4-10 years and 10 years after SVR. The longest duration from SVR to HCC was 18.7 years. Independent factors associated with HCC development were anti-HBc positivity (hazard ratio [HR] 5.57, P = 0.012), age at SVR (HR 1.08, P = 0.014), higher pre-antiviral treatment AFP levels (HR 1.01, P = 0.01) and Hispanic ethnicity (HR 12.9, P = 0.002). HCC risk was significantly less in genotype 2 patients (HR 0.2, P = 0.02) or in those with higher pre-antiviral treatment albumin levels (HR 0.33, P = 0.04).

CONCLUSIONS

The risk for HCC exists in a subset of CHC patients after SVR and may occur up to 18 years after viral clearance. Indefinite HCC surveillance is necessary in SVR patients with other risk factors.

Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles

Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml^-1, the linear range from 5 pg ml^-1 to 1 ng ml^-1 and the detection limit of 1.34 pg ml^-1, at a signal-to-noise ratio of 3.

Hepatitis B cure: From discovery to regulatory approval

The majority of persons currently treated for chronic hepatitis B require long-term or lifelong therapy. New inhibitors of hepatitis B virus entry, replication, assembly, or secretion and immune modulatory therapies are in development. The introduction of these novel compounds for chronic hepatitis B necessitates a standardised appraisal of the efficacy and safety of these treatments and definitions of new or additional endpoints to inform clinical trials. To move the field forward and to expedite the pathway from discovery to regulatory approval, a workshop with key stakeholders was held in September 2016 to develop a consensus on treatment endpoints to guide the design of clinical trials aimed at hepatitis B cure. The consensus reached was that a complete sterilising cure, i.e., viral eradication from the host, is unlikely to be feasible. Instead, a functional cure characterised by sustained loss of hepatitis B surface antigen with or without hepatitis B surface antibody seroconversion, which is associated with improved clinical outcomes, in a higher proportion of patients than is currently achieved with existing treatments is a feasible goal. Development of standardised assays for novel biomarkers toward better defining hepatitis B virus cure should occur in parallel with development of novel antiviral and immune modulatory therapies such that approval of new treatments can be linked to the approval of new diagnostic assays used to measure efficacy or to predict response. Combination of antiviral and immune modulatory therapies will likely be needed to achieve functional hepatitis B virus cure. Limited proof-of-concept monotherapy studies to evaluate safety and antiviral activity should be conducted prior to proceeding to combination therapies. The safety of any new curative therapies will be paramount given the excellent safety of currently approved nucleos(t)ide analogues.

Hepatitis B cure: From discovery to regulatory approval

The majority of persons currently treated for chronic hepatitis B require long-term or lifelong therapy. New inhibitors of hepatitis B virus entry, replication, assembly, or secretion and immune modulatory therapies are in development. The introduction of these novel compounds for chronic hepatitis B necessitates a standardized appraisal of the efficacy and safety of these treatments and definitions of new or additional endpoints to inform clinical trials. To move the field forward and to expedite the pathway from discovery to regulatory approval, a workshop with key stakeholders was held in September 2016 to develop a consensus on treatment endpoints to guide the design of clinical trials aimed at hepatitis B cure. The consensus reached was that a complete sterilizing cure, i.e., viral eradication from the host, is unlikely to be feasible. Instead, a functional cure characterized by sustained loss of hepatitis B surface antigen with or without hepatitis B surface antibody seroconversion, which is associated with improved clinical outcomes, in a higher proportion of patients than is currently achieved with existing treatments is a feasible goal. Development of standardized assays for novel biomarkers toward better defining hepatitis B virus cure should occur in parallel with development of novel antiviral and immune modulatory therapies such that approval of new treatments can be linked to the approval of new diagnostic assays used to measure efficacy or to predict response. Combination of antiviral and immune modulatory therapies will likely be needed to achieve functional hepatitis B virus cure. Limited proof-of-concept monotherapy studies to evaluate safety and antiviral activity should be conducted prior to proceeding to combination therapies. The safety of any new curative therapies will be paramount given the excellent safety of currently approved nucleos(t)ide analogues. (Hepatology 2017).

Current treatment guidelines of chronic hepatitis B: The role of nucleos(t)ide analogues and peginterferon

Chronic hepatitis B is prevalent worldwide and is a major contributor to death from cirrhosis and hepatocellular carcinoma. Thus, the goals of therapy are to prevent the development of cirrhosis, hepatocellular carcinoma and liver-related death. Safe and effective therapy is available but complete cure is not yet possible. The decision to treat is complex and must be individualized. Each of the three major liver societies, the American Association for the Study of Liver Diseases (AASLD), the European Association for the Study of the Liver (EASL) and the Asian Pacific Association for the Study of the Liver (APASL) have developed treatment guidelines to provide healthcare professionals guidance on management of chronic HBV infection. This review will cover the specific, evidence-based or expert opinion guideline recommendations on who should be treated, what to treat with, how to monitor, when to stop therapy and management of treatment failure.

Removal of Integrated Hepatitis B Virus DNA Using CRISPR-Cas9

The presence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) and the permanent integration of HBV DNA into the host genome confers the risk of viral reactivation and hepatocellular carcinoma. Nucleoside/nucleotide analogs alone have little or no capacity to eliminate replicative HBV templates consisting of cccDNA or integrated HBV DNA. Recently, CRISPR/Cas9 technology has been widely applied as a promising genome-editing tool, and HBV-specific CRISPR-Cas9 systems were shown to effectively mediate HBV cccDNA disruption. However, the integrated HBV DNA fragments are considered as important pro-oncogenic properties and it serves as an important template for viral replication and expression in stable HBV cell line. In this study, we completely excised a full-length 3,175-bp integrated HBV DNA fragment and disrupted HBV cccDNA in a stable HBV cell line. In HBV-excised cell line, the HBV cccDNA inside cells, supernatant HBV DNA, HBsAg, and HBeAg remained below the negative critical values for more than 10 months. Besides, by whole genome sequencing, we analyzed off-target effects and excluded cell contamination. It is the first time that the HBV infection has been fully eradicated in a stable HBV cell line. These findings demonstrate that the CRISPR-Cas9 system is a potentially powerful tool capable of promoting a radical or “sterile” HBV cure.

Review article: novel therapies for hepatitis B virus cure - advances and perspectives

BACKGROUND

Current anti-viral therapies, interferon and nucleos(t)ide analogues, have been proven to reduce the progression of chronic hepatitis B (CHB). However, covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) persists, resulting in viral relapse after the discontinuation of treatment.

AIM

To discuss and review novel therapies for chronic hepatitis B infection.

METHODS

Recent published studies which searched from PubMed were comprehensive reviewed. The key words include chronic hepatitis B, hepatitis B virus cure, covalently closed circular DNA, direct acting anti-virals and host targeting agents.

RESULTS

Several novel agents through viral and host targets approaches are under investigations towards functional cure of HBV. On the one hand, direct acting anti-virals targeting virus itself, such as HBV new polymerase inhibitor, entry inhibitor, engineered site-specific nucleases and RNA interference, could inhibit amplification of cccDNA as well as intrahepatic HBV infection and eliminate or silence cccDNA transcription. Inhibitors of HBV nucleocapsid assembly suppress capsid formation and prevent synthesis of HBV DNA. On the other hand, host targeting agents (HTA) include lymphotoxin-β receptor agonist, toll-like receptor agonist, immune checkpoint inhibitors and adenovirus-based therapeutic vaccine. Through enhancing innate and adaptive immune responses, these agents could induce noncytolytic destruction of cccDNA or attack HBV-infected hepatocytes.

CONCLUSION

With these promising approaches, we hope to reach global hepatitis B virus control in the middle of this century.