Combining hepatitis B core-related and surface antigens at end of nucleos(t)ide analogue treatment to predict off-therapy relapse risk

Combining end-of-treatment HBsAg and baseline hepatitis B core-related antigen reduce HBV relapse rate after tenofovir cessation

BACKGROUND/PURPOSE

The study investigated the role of hepatitis B core-related antigen (HBcrAg) in hepatitis B virus (HBV) relapse after stopping tenofovir disoproxil fumarate (TDF) in HBeAg-negative patients.

METHODS

A total of 185 HBeAg-negative patients without cirrhosis who had stopped TDF treatment for at least 6 months were recruited. All patients fulfilled the stopping criteria proposed by the Asian Pacific Association for the Study of the Liver 2012.

RESULTS

The 3-year cumulative incidences of virological relapse, clinical relapse, and hepatitis B surface antigen (HBsAg) loss were 72, 60.1 and 14.5%, respectively. End-of-treatment (EOT) HBsAg level was an independent predictor of virological relapse (hazard ratio (HR): 2.263; 95% confidence interval (CI): 1.779-2.887), clinical relapse (HR 1.773; 95% CI 1.367-2.298), and HBsAg loss (HR 0.179; 95% CI 0.096-0.335). Among patients who had HBsAg < 100 and ≥ 100 IU/mL, the 3-year virological relapse rates were 37.4% and 85.3% (p < 0.001), clinical relapse rates were 30.3 and 71.7% (p < 0.001), and HBsAg loss rates were 40.6 and 2.6% (p < 0.001), respectively. Among the 53 patients with EOT HBsAg level < 100 IU/mL, the 3-year virological relapse rates in patients with baseline HBcrAg levels < 4.7 and ≥ 4.7 log₁₀ U/mL were 20.3 and 60.4% (p = 0.003), and the clinical relapse rates were 10.3 and 59.5% (p < 0.001) respectively. Additionally, the 3-year HBsAg loss rates in patients with baseline HBcrAg ≤ 3 and > 3 log₁₀ U/mL were 42.9 and 7.9% (p < 0.001).

CONCLUSIONS

The combination of EOT HBsAg and baseline HBcrAg levels could further reduce the risk of HBV relapse after stopping TDF therapy in HBeAg-negative patients.

HBeAg-positive patients with HBsAg < 100 IU/mL and negative HBV RNA have lower risk of virological relapse after nucleos(t)ide analogues cessation

BACKGROUND

Nucleos(t)ide analogues (NAs) cessation is not widely practiced and remains a controversial, but highly relevant subject in patients infected with hepatitis B virus (HBV). We aimed to explore the related factors for safe NAs cessation.

METHODS

This is a multicenter prospective cohort study. Overall, 139 initially HBV e antigen (HBeAg)-positive patients meeting the stopping criteria were included in 12 hospitals in China. Enrolled patients ceased NAs and were followed up every 3 months for 24 months or until clinical relapse (CR).

RESULTS

The 24 month cumulative rates of virological relapse (VR), CR, HBeAg reversion and HBV surface antigen (HBsAg) loss were 50.4, 24.5, 11.5 and 9.4%, respectively. Patients with end of treatment (EOT) HBsAg  < 100 IU/mL plus negative HBV RNA had the lowest 24 month cumulative VR rate (5 vs 58%, p < 0.001). EOT HBsAg  ≥ 2 log₁₀ IU/mL [odds ratio (OR) = 6.686, p = 0.006], EOT positive HBV RNA (OR = 3.453, p = 0.008) and EOT hepatitis B core-related antigen (HBcrAg)  ≥ 4log U/mL (OR = 3.702, p = 0.002) were found to independently predict the risk of VR. To predict VR, the area under the receiver-operating characteristic (AUROC) value of the EOT HBsAg  < 100 IU/mL plus EOT HBV RNA negative was 0.698 (p < 0.001), which was higher than other parameters alone or combinations.

CONCLUSIONS

NAs cessation is suitable only for a small and selected patients. An EOT HBsAg  < 100 IU/mL and EOT negative HBV RNA identified a patient with low risk of off-treatment VR.

Pilot Study Using Machine Learning to Identify Immune Profiles for the Prediction of Early Virological Relapse After Stopping Nucleos(t)ide Analogues in HBeAg-Negative CHB

Treatment with nucleos(t)ide analogues (NAs) may be stopped after 1-3 years of hepatitis B virus DNA suppression in hepatitis B e antigen (HBeAg)-negative patients according to Asian Pacific Association for the Study of Liver and European Association for the Study of Liver guidelines. However, virological relapse (VR) occurs in most patients. We aimed to analyze soluble immune markers (SIMs) and use machine learning to identify SIM combinations as predictor for early VR after NA discontinuation. A validation cohort was used to verify the predictive power of the SIM combination. In a post hoc analysis of a prospective, multicenter therapeutic vaccination trial (ABX-203, NCT02249988), hepatitis B surface antigen, hepatitis B core antigen, and 47 SIMs were repeatedly determined before NA was stopped. Forty-three HBeAg-negative patients were included. To detect the highest predictive constellation of host and viral markers, a supervised machine learning approach was used. Data were validated in a different cohort of 49 patients treated with entecavir. VR (hepatitis B virus DNA ≥ 2,000 IU/mL) occurred in 27 patients. The predictive value for VR of single SIMs at the time of NA stop was best for interleukin (IL)-2, IL-17, and regulated on activation, normal T cell expressed and secreted (RANTES/CCL5) with a maximum area under the curve of 0.65. Hepatitis B core antigen had a higher predictive power than hepatitis B surface antigen but lower than the SIMs. A supervised machine-learning algorithm allowed a remarkable improvement of early relapse prediction in patients treated with entecavir. The combination of IL-2, monokine induced by interferon γ (MIG)/chemokine (C-C motif) ligand 9 (CCL9), RANTES/CCL5, stem cell factor (SCF), and TNF-related apoptosis-inducing ligand (TRAIL) was reliable in predicting VR (0.89; 95% confidence interval: 0.5-1.0) and showed viable results in the validation cohort (0.63; 0.1-0.99). Host immune markers such as SIMs appear to be underestimated in guiding treatment cessation in HBeAg-negative patients. Machine learning can help find predictive SIM patterns that allow a precise identification of patients particularly suitable for NA cessation.

Perspectives on stopping nucleos(t)ide analogues therapy in patients with chronic hepatitis B

Long-term treatment with nucleos(t)ide analogs (NAs) is the current first line therapy for patients with chronic hepatitis B (CHB), recommended by most of the current guidelines. NAs prevent disease progression, liver failure, decrease the risk of hepatocellular carcinoma (HCC), and have favorable safety profiles. However, low rates of on-therapy functional cure (hepatitis B surface antigen [HBsAg] loss), which is regarded as the optimal end point, prevent many patients from stopping NA therapy with the need for a lifelong treatment. The higher likelihood of HBsAg loss associated with stopping as compared to continuing NAs has got a lot of attention recently. Recommendations regarding endpoints allowing for safely stopping NA therapy differ between international guidelines. Whereas in HBeAg-positive patients, HBeAg seroconversion with at least one year of consolidation therapy is an acceptable endpoint of treatment, the recommendations for HBeAg-negative ones differ. Some guidelines propose ≥3 years of HBV DNA undetectability to stop NA while others regard HBsAg loss as the only acceptable endpoint. Stopping NA can lead to substantial rates of virologic relapses and consequent ALT flares in some cases. Moreover, no reliable predictor(s) of post-NA relapses have been identified so far. Quantitative HBsAg is becoming an increasingly promising marker to predict safe NA cessation. On the other hand, investigating the role of the immune system in mediating sustained virologic responses after NA withdrawal is needed to suggest immunological biomarkers to safely stop NA. In this article, we will review relevant literature regarding NA stopping strategy and discuss promising viral and immunological biomarkers to predict antiviral responses and thus to help identify patients who are more likely to achieve HBsAg seroclearance.

Hepatitis B surface antigen, core-related antigen and HBV RNA: Predicting clinical relapse after NA therapy discontinuation

BACKGROUND & AIMS

The safe discontinuation of nucleos(t)ide analogue therapy remains challenging in chronic hepatitis B. We investigated the potential role of quantitative hepatitis B surface antigen, hepatitis B core-related antigen and hepatitis B virus RNA at the end of treatment in predicting off-therapy relapse.

METHODS

Patients who fulfilled the stopping criteria of the Asian Pacific Association for the Study of the Liver guideline were enrolled. Virological relapse was defined as hepatitis B virus DNA level greater than 2000 IU/mL, and clinical relapse was defined as virological relapse plus alanine aminotransferase level of more than twice the upper limit of normal.

RESULTS

Ninety-two patients participated. The combination of end-of-treatment hepatitis B core-related antigen and hepatitis B virus RNA levels was most predictive of clinical relapse. Multivariate analysis revealed that end-of-treatment hepatitis B core-related antigen and hepatitis B virus RNA were independently associated with clinical relapse. During follow-up, no patients with undetectable hepatitis B core-related antigen (<3.0 log₁₀ U/mL) and hepatitis B virusRNA (<2.0 log₁₀ copies/mL) at end of treatment developed clinical relapse, in comparison with 22.9% and 62.5% patients with detectable levels of one or both biomarkers respectively. End-of-treatment quantitative hepatitis B surface antigen was linked to a likelihood of hepatitis B surface antigen clearance.

CONCLUSIONS

The combined hepatitis B core-related antigen and hepatitis B virus RNA assays at end of treatment were highly predictive of subsequent clinical relapse. These novel biomarkers could potentially be used to identify patients who could safely discontinue nucleos(t)ide analogue therapy.

Incidence and Factors Associated With HBV Relapse After Cessation of Entecavir or Tenofovir in Patients With HBsAg Below 100 IU/mL

BACKGROUND & AIMS

We investigated the incidence and factors associated with relapse of hepatitis B virus (HBV) infection in patients with levels of HB surface antigen (HBsAg) less than 100 IU/mL after cessation of entecavir or tenofovir disoproxil fumarate (TDF) treatment.

METHODS

We collected data from patients with chronic HBV infection without cirrhosis treated with entecavir from 2007 through 2015 or TDF from 2011 through 2016 in Taiwan. We identified 135 patients with levels of HBsAg less than 100 IU/mL at the end of treatment (79 entecavir and 56 TDF) and collected data from them for a median of 87 weeks (interquartile range, 48-161 wk) for use as the development set. We collected data from 108 patients from separate medical centers in Taiwan, followed up for a median of 126 weeks (interquartile range, 61-214 wk), and used these as the validation group. Post-treatment virologic relapse was defined as a serum HBV DNA level greater than 2000 IU/mL, and clinical relapse was defined as an alanine aminotransferase level greater than 80 U/L and a HBV DNA level greater than 2000 IU/mL.

RESULTS

In the development group, the 5-year incidences of virologic relapse, clinical relapse, and HBsAg loss were 40.9%, 32.5%, and 47%, respectively. The baseline HBV DNA and end-of-treatment levels of HBsAg were associated independently with relapse. In the development group, 17.3% of patients with end-of-treatment HBsAg levels less than 40 IU/mL had a virologic relapse within 5 years, whereas 67.6% of patients with a HBsAg level of 40 IU/mL or more had a virologic relapse within 5 years (P < .001); proportions of patients with clinical relapses were 10.2% (HBsAg <40 IU/mL) and 57.6% (HBsAg ≥40 IU/mL; P < .001). In the validation groups, for patients with end-of-treatment HBsAg levels less than 40 IU/mL or 40 IU/mL or more, the rates of virologic relapse at 5 years were 31.1% and 80.5% (P < .001), and rates of clinical relapse were 14.2% and 50.3% (P < .001), respectively. Rates of virologic and clinical relapse within 5 years were low (<10%) in patients with a combination of end-of-treatment HBsAg level less than 40 IU/mL and baseline HBV DNA level less than 5 × 10⁴ IU/mL, or baseline hepatitis B core-related antigen level less than 4 log U/mL in the development group.

CONCLUSIONS

An end-of-treatment HBsAg level of 40 IU/mL or less is optimal for stopping nucleos(t)ide analog therapy. Waiting to stop therapy until patients have a combination of baseline HBV DNA level of 5 × 10⁴ IU/mL or hepatitis B core-related antigen of 4 log U/mL and end-of-treatment HBsAg level of 40 IU/mL might reduce the risk of HBV relapse.

The Yin and the Yang of Treatment for Chronic Hepatitis B-When to Start, When to Stop Nucleos(t)ide Analogue Therapy

Over 257 million individuals worldwide are chronically infected with the Hepatitis B Virus (HBV). Nucleos(t)ide analogues (NAs) are the first-line treatment option for most patients. Entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are both potent, safe antiviral agents, have a high barrier to resistance, and are now off patent. They effectively suppress HBV replication to reduce the risk of cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Treatment is continued long-term in most patients, as NA therapy rarely induces HBsAg loss or functional cure. Two diverging paradigms in the treatment of chronic hepatitis B have recently emerged. First, the public health focussed "treat-all" strategy, advocating for early and lifelong antiviral therapy to minimise the risk of HCC as well as the risk of HBV transmission. In LMICs, this strategy may be cost saving compared to monitoring off treatment. Second, the concept of "stopping" NA therapy in patients with HBeAg-negative disease after long-term viral suppression, a personalised treatment strategy aiming for long-term immune control and even HBsAg loss off treatment. In this manuscript, we will briefly review the current standard of care approach to the management of hepatitis B, before discussing emerging evidence to support both the "treat-all" strategy, as well as the "stop" strategy, and how they may both have a role in the management of patients with chronic hepatitis B.

Consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B virus infection (2020)

Hepatitis B virus (HBV) infection remains a global public health problem. HBV vaccination is the most effective tool to reduce the incidence of HBV disease. Despite there has not been new clinical developments for the treatment of chronic hepatitis B in the last few years, changing epidemiology and current insights on natural history, diagnostic tools and therapy indications make necessary an update of the former version of the consensus document of the Spanish Association for Study of the Liver on the treatment of hepatitis B infection published in 2012. The current document updates the management of chronic hepatitis B. The treatment of choice is the long-term administration of a nucleos(t)ide analogue with high barrier to resistance (entecavir, tenofovir or tenofovir alafenamide). Pegylated interferon may be an option in patients with non-advanced liver disease, but its applicability is limited due to the low efficacy and poor tolerability. All patients must be monitored for the risk of progression to advanced liver disease and development of hepatocellular carcinoma.

Novel biomarkers for the management of chronic hepatitis B

Hepatitis B virus (HBV) cannot be eliminated completely from infected hepatocytes because of the presence of intrahepatic covalently closed circular DNA (cccDNA). As chronic hepatitis B (CHB) can progress to cirrhosis and hepatocellular carcinoma (HCC), it is important to manage CHB to prevent HCC development in high-risk patients with high viral replicative activity or advanced fibrosis. Serum biomarkers are noninvasive and valuable for the management of CHB. Hepatitis B core-related antigen (HBcrAg) correlates with serum HBV DNA and intrahepatic cccDNA. In CHB patients with undetectable serum HBV DNA or loss of HBsAg, HBcrAg still can be detected and the decrease in HBcrAg levels is significantly associated with hopeful outcomes. Therefore, HBcrAg can predict HCC occurrence or recurrence. Measurement of the Mac-2 binding protein glycosylation isomer (M2BPGi) has been introduced for the evaluation of liver fibrosis. Because elevated M2BPGi in CHB is related to liver fibrosis and the prediction of HCC development, monitoring its progression is essential. Because alpha fetoprotein (AFP) has insufficient sensitivity and specificity for early-stage HCC, a combination of AFP plus protein induced by vitamin K absence factor II, or AFP plus Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein might improve the diagnosis of HCC development. Additionally, Dickkopf-1 and circulating immunoglobulin G antibodies are the novel markers to diagnose HCC or assess HCC prognosis. This review provides an overview of novel HBV biomarkers used for the management of intrahepatic viral replicative activity, liver fibrosis, and HCC development.

Emerging Diagnostic Tools to Decide When to Discontinue Nucleos(t)ide Analogues in Chronic Hepatitis B

The aim of this review is to outline emerging biomarkers that can serve as diagnostic tools to identify non-cirrhotic chronic hepatitis B (CHB) patients who could safely discontinue nucleos(t)ide analogues (NAs) before HBsAg loss. Regarding possible predictors of post-NAs outcomes, a number of studies have evaluated numerous factors, which can be categorised in markers of hepatitis B virus (HBV) activity, markers of host immune response and markers of other patient characteristics. In clinical practice, the most important question for patients who discontinue NAs is to differentiate those who will benefit by achieving HBsAg loss or at least by remaining in remission and those who will relapse requiring retreatment. Most of the discontinuation studies so far came from Asian and only few from European populations and examined the rates and predictors of post-NA virological and/or combined relapses or HBsAg loss. To date, there is still controversy about predictors of post-NA relapses, while only HBsAg serum levels at NA discontinuation seem to be the most robust predictive marker of the probability of subsequent off-treatment HBsAg seroclearance. Newer viral markers such as HBV RNA and hepatitis B core-related antigen seem promising, but further research is required.

Predictors of hepatitis B surface antigen loss, relapse and retreatment after discontinuation of effective oral antiviral therapy in noncirrhotic HBeAg-negative chronic hepatitis B

Reliable predictors of outcomes after treatment discontinuation in HBeAg-negative chronic hepatitis B (CHB) patients have not been established. We investigated the role of hepatitis B surface antigen (HBsAg), interferon-inducible protein-10 (IP10) and hepatitis B core-related antigen (HBcrAg) serum levels as predictors of HBsAg loss, relapse and retreatment in noncirrhotic HBeAg-negative CHB patients who discontinued long-term antiviral therapy. All HBsAg-positive (n = 57) patients of the prospective DARING-B study were included and followed monthly for 3 months, every 2/3 months until month-12 and every 3/6 months thereafter. HBsAg, IP10 and HBcrAg levels were measured by enzyme immunoassays, and SCALE-B score was calculated. Twelve patients achieved HBsAg loss before retreatment with 18-month cumulative incidence of 25%. Independent predictors of HBsAg loss were baseline HBsAg and month-1 IP10 levels. Of 10 patients with baseline HBsAg ≤100 IU/mL, 70% cleared HBsAg and 10% required retreatment. Of 23 patients with baseline HBsAg >1000 IU/mL, 4% cleared HBsAg and 43% required retreatment. Of 24 patients with intermediate baseline HBsAg (100-1000 IU/mL), 17% cleared HBsAg and 21% required retreatment; in this subgroup, month-1 IP10 was significantly associated with HBsAg loss, which occurred in 30% and 7% of cases with IP10 >150 and ≤150 pg/mL, respectively. Baseline HBcrAg was undetectable in all patients who cleared HBsAg and was associated with retreatment. SCALE-B was associated with HBsAg loss but not with relapse or retreatment. In conclusion, HBsAg, IP10 and HBcrAg serum levels can be useful for the decisions and management of treatment discontinuation in noncirrhotic Caucasian patients with HBeAg-negative CHB.

The role of hepatitis B core-related antigen in predicting hepatitis B virus recurrence after liver transplantation

BACKGROUND

Hepatitis B core-related antigen (HBcrAg) is a viral marker for the development of cirrhosis and hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). However, the relationship between HBcrAg and HBV recurrence after liver transplantation (LT) is unclear.

AIM

To investigate the correlation of serum HBcrAg level with HBV recurrence post-LT to evaluate the prognostic role of the pre-LT HBcrAg level.

METHODS

This retrospective cohort study enrolled 357 CHB patients who received LT for a median of 36.6 months. Univariate and multivariate analyses and time-dependent receiver operating characteristic (ROC) curves for markers associated with HBV recurrence were analysed.

RESULTS

48 patients (13.4%) had HBV recurrence after LT. HBcrAg, detectable HBV DNA, HCC and HCC recurrence were associated with HBV recurrence. In a multivariate analysis, HBcrAg level was independently associated with HBV recurrence, and the relationship between HBcrAg level and incident HBV recurrence was significant and graded (HR: 3.17 per unit; 95% CI: 1.97-5.11; P for trend < .001). Additionally, HBcrAg level was superior to HBV DNA level in predicting HBV recurrence by time-dependent ROC analysis. Patients with an HBcrAg ≥ 5.0 log U/mL had a significantly higher 5-year cumulative recurrence rate than those with an HBcrAg < 5.0 log U/mL (37.6% vs 6%, P < .001); the adjusted hazard ratio was 5.27 (95% CI 2.47-11.25, P < .001).

CONCLUSION

An elevated serum HBcrAg level was independently associated with the risk of HBV recurrence in patients with CHB after LT.

Clinical utility of HBV surface antigen quantification in HBV e antigen-negative chronic HBV infection

Chronic hepatitis B virus (HBV) infection is a serious problem owing to its worldwide distribution and potential adverse sequelae that include cirrhosis and/or hepatocellular carcinoma. Current antiviral therapies have much improved outcomes, but few patients achieve the ultimate goal of hepatitis B surface antigen (HBsAg) loss (functional cure). As hepatitis B e antigen (HBeAg)-negative chronic HBV infection is the final phase prior to HBsAg loss, the management of patients in this phase together with quantification of HBsAg has attracted increasing clinical and research interest. This Review integrates the findings from research in HBsAg kinetics and discusses how they might inform our understanding and management of HBeAg-negative chronic HBV infection. Studies have shown that HBsAg levels are highly predictive of the presence of inactive HBV infection and that serial changes in HBsAg levels might predict HBsAg loss within 1-3 years. Data also suggest that quantitative HBsAg monitoring is important during hepatitis flare and antiviral therapy, especially in the timing of the decision to stop therapy and to start off-therapy retreatment. These findings have shed new light on the natural course of HBV infection and might lead to optimization of the management of HBeAg-negative chronic HBV infection and contribute to the paradigm shift from indefinite to finite therapy for patients with HBV infection.

On-treatment monitoring of liver fibrosis with serum hepatitis B core-related antigen in chronic hepatitis B

BACKGROUND

Non-invasive evaluation for liver fibrosis is clinically important, especially in patients with undetectable hepatitis B virus (HBV) DNA treated with nucleoside analogs.

AIM

To clarify the monitoring power of hepatitis B core-related antigen (HBcrAg) for hepatic histologic changes in patients with chronic hepatitis B (CHB) treated with entecavir.

METHODS

This prospective multicenter study used multiple ordinal and multivariate logistics regression analysis to assess variables associated with Ishak fibrosis score and regression for fibrosis regression, respectively, in 403 CHB patients, including 374 with entecavir for 72 weeks (291 underwent paired liver biopsy) and 29 as controls.

RESULTS

Level of HBcrAg correlated negatively with liver fibrosis staging (γ = -0.357, P < 0.001) in hepatitis B e antigen (HBeAg)-positive patients, and positively with liver fibrosis staging in HBeAg-negative patients. Higher HBcrAg concentration was associated with younger age, HBeAg positive status, high HBV DNA loads, high level of hepatitis B surface antigen (HBsAg) and higher necroinflammation, but not with HBV genotype. Serum concentration of HBcrAg, basal core promoter/precore (BCP/PC) mutant, quantitation of HBsAg (qHBsAg) and platelet counts were independently associated with Ishak fibrosis score on multiple ordinal regression. HBV DNA was undetectable in 88.37% of patients treated with entecavir at week 72, while their level of HBcrAg was still detectable. A greater reduction in post-treatment HBcrAg concentration was associated with the regression of hepatic fibrosis and histological improvement. HBcrAg concentration > 6.33 log IU/mL at baseline and logarithmic reduction > 1.03 log IU/mL at week 72 were associated with a higher chance of regression of liver fibrosis and histological improvement, respectively.

CONCLUSION

HBcrAg level is associated with liver fibrosis progression. HBcrAg is an excellent monitor of hepatic histological changes, especially in CHB patients treated with nucleoside analogs.

The Role of Hepatitis B Core-Related Antigen

Hepatitis B virus (HBV) cannot be completely eliminated from infected hepatocytes due to the existence of intrahepatic covalently closed circular DNA (cccDNA). Serological biomarkers reflect intrahepatic viral replicative activity as non-invasive alternatives to liver biopsy. Hepatitis B core-related antigen (HBcrAg) is a novel biomarker that has an important role in chronic hepatitis B (CHB), because it correlates with serum HBV DNA and intrahepatic cccDNA. In clinical cases with undetectable serum HBV DNA or loss of HBsAg, HBcrAg still can be detected and the decrease in HBcrAg levels is significantly associated with promising outcomes for CHB patients. HBcrAg can predict spontaneous or treatment-induced hepatitis B envelope antigen (HBeAg) seroconversion, persistent responses before and after cessation of nucleos(t)ide analogues, potential HBV reactivation, HBV reinfection after liver transplantation, and risk of hepatocellular carcinoma progression or recurrence. In this review, the clinical applications of HBcrAg in CHB patients based on its virological features are described. Furthermore, new potential therapeutic anti-HBV agents that affect intrahepatic cccDNA are under development, and the monitoring of HBcrAg might be useful to judge therapeutic effects. In conclusion, HBcrAg might be a suitable surrogate marker beyond other HBV markers to predict the disease progression and treatment responses of CHB patients.