Factors associated with serum hepatitis B surface antigen levels and its on-treatment changes in patients under lamivudine therapy

α-Fetoprotein level-dependent early hepatitis B surface antigen decline during entecavir therapy in chronic hepatitis B with hepatitis flare

OBJECTIVES

Hepatitis B surface antigen (HBsAg) reduction during nucleos(t)ide analogue therapy is related to ALT level. ALT reflects hepatocytolysis while α-fetoprotein (AFP) ≥100 ng/mL during hepatitis flare reflects more extensive hepatocytolysis (bridging hepatic necrosis). The impact of AFP levels on early HBsAg kinetics during entecavir therapy was investigated.

METHODS

HBsAg level was measured at baseline and months 6 and 12 of entecavir therapy in 149 chronic hepatitis B patients with hepatitis flare, defined as ALT ≥5× upper limit of normal (ULN), and 58 patients with ALT <5× ULN.

RESULTS

There was a significantly greater HBsAg reduction in an ALT (<5, 5-10, 10-20 and ≥20× ULN, P = 0.001) and AFP (<20, 20-99 and ≥100 ng/mL, P = 0.000) level-dependent manner. In hepatitis flares with a peak AFP level ≥20 ng/mL, the differences in HBsAg reduction across all ALT levels became non-significant. HBsAg reduction was greater in genotype B- than genotype C-infected patients with baseline ALT ≥20× ULN, but the difference became non-significant in those with peak AFP ≥100 ng/mL. Multivariate linear regression analysis showed that AFP level ≥100 ng/mL, baseline HBsAg level and genotype B were independent significant factors for greater HBsAg decline at month 6 of entecavir therapy.

CONCLUSIONS

During entecavir therapy, early HBsAg reduction increased in an AFP and ALT level-dependent manner, suggesting the impact of hepatocytolysis rather than nucleos(t)ide analogue per se. Notably, a higher AFP level during hepatitis flare, reflecting more extensive hepatic necrosis, was a more powerful factor than ALT and genotype for greater HBsAg decline.

HBsAg quantification: useful for monitoring natural history and treatment outcome

The template of hepatitis B virus transcription, the covalently closed circular DNA (cccDNA), plays a key role in the life cycle of the virus and permits the persistence of infection. It has been suggested that hepatitis B surface antigen (HBsAg) quantification reflects the concentration of cccDNA in the liver. In hepatitis B e antigen (HBeAg) positive chronic hepatitis B, HBsAg levels are higherduring the immune tolerance phase than during the immune clearance phase. During the natural history of chronic hepatitis B, serum HBsAg declines progressively from the immune-tolerant to the low replicative phase. In HBeAg negative patients, the combination of low hepatitis B virus (HBV) DNA (<2000 IU/ml) and low HBsAg levels (<1000 IU/ml) can predict inactive carrier status, low risk of hepatocellular carcinoma, and the probability of HBsAg loss. HBsAg in combination with HBV DNA predicts the outcome of Peg-Interferon therapy: An absence of decline at week 12 is a good predictor of non-response and to stop therapy. Any decline at week 24, suggests that therapy should be continued to 48 weeks. Although the decrease in HBsAg decline slow with nucleos(t)ide analogue therapy, a rapid decline can predict future HBsAg seroclearance. A level <100 IU/ml during six consecutive months could be a marker of a sustained response after treatment cessation.

Serum hepatitis B surface antigen quantification as a useful assessment for significant fibrosis in hepatitis B e antigen-positive hepatitis B virus carriers

BACKGROUND AND AIMS

The role of serum quantitative hepatitis B surface antigen (qHBsAg) in identifying hepatitis B virus (HBV) carriers with significant fibrosis is unknown. This study aims to evaluate the diagnostic value of qHBsAg for hepatic fibrosis in hepatitis B e antigen (HBeAg)-positive HBV carriers.

METHODS

Consecutive biopsy-proven HBeAg-positive HBV carriers were prospectively recruited in our center from 2009 to 2011 and were randomly divided into training and validation set. Area under receiver-operator curve (AUC) was used to determine the diagnostic accuracy of simple tests for significant fibrosis (Scheuer stage, F ≥ 2).

RESULTS

Overall, a total of 197 eligible patients (median age 31 years; 149 males) were enrolled. The median qHBsAg was 4.20 (log10 IU/mL). Significant fibrosis was confirmed in 112 (56.9%) patients. By logistical regression analysis, qHBsAg and γ-glutamyl transpeptidase were identified as predictors for significant fibrosis in training set (n = 124). Thus, qHBsAg index and γ-glutamyl transpeptidase to qHBsAg ratio (GqHBsR) were selected for the subsequent analysis. In the training set, an AUC of 0.762, 0.826, 0.749, and 0.771 was observed for qHBsAg index, GqHBsR, FIB-4, and aspartate aminotransferase to platelet ratio index, respectively (all P < 0.05). GqHBsR yielded a higher AUC than aspartate aminotransferase to platelet ratio index and FIB-4 (both P < 0.05). Using the optimal cut-off of 7.78, GqHBsR showed a sensitivity of 78.9% and a specificity of 73.6%. About 80% of liver biopsy could be avoided in the entire cohort.

CONCLUSIONS

Serum qHBsAg-based simple tests, especially GqHBsR, can accurately and specifically identify significant fibrosis in treatment-naïve HBeAg-positive HBV carriers.

Efficacy of adefovir-based combination therapy for patients with Lamivudine- and entecavir-resistant chronic hepatitis B virus infection

Treatment strategies for entecavir (ETV)-resistant chronic hepatitis B (CHB) patients are not yet well established. The aim of this study was to evaluate overall antiviral efficacy and to compare the efficacy of combination therapy with adefovir (ADV) plus nucleoside analogues (lamivudine [LAM], telbivudine [LdT], or ETV) in patients infected with LAM- and ETV-resistant hepatitis B virus (HBV) variants. Virologic, biochemical, and serologic responses during combination therapy with ADV plus nucleoside analogues were assessed. Propensity score analysis was used to select a matched group of patients for the comparison of rescue therapy regimens. A total of 67 consecutive patients were analyzed. Complete virologic suppression was achieved in 27 patients. The overall cumulative incidence of complete virologic suppression at month 24 was 47.4%: 44.3% in the LAM or LdT plus ADV group and 51.4% in the group given ETV and ADV. There was no significant difference between these two groups (P = 0.234). The cumulative incidences of complete virologic suppression were still comparable between the two groups selected and matched using the propensity score model (P = 0.419). Virologic breakthrough was observed in 9 patients, and rtA181V substitution was newly detected in one patient. Hepatitis B e antigen (HBeAg) negativity and lower baseline HBV DNA level were associated with complete virologic suppression in univariate analysis. In multivariate analysis, lower baseline HBV DNA level remained an independent predictor. In conclusion, combination therapy with ADV plus nucleoside analogues fails to show sufficient antiviral efficacy in CHB patients with resistance to both LAM and ETV. Further study is warranted to evaluate the efficacy of a more potent tenofovir-based regimen in such patients.

Efficacy of adefovir-based combination therapy for patients with Lamivudine- and entecavir-resistant chronic hepatitis B virus infection

Treatment strategies for entecavir (ETV)-resistant chronic hepatitis B (CHB) patients are not yet well established. The aim of this study was to evaluate overall antiviral efficacy and to compare the efficacy of combination therapy with adefovir (ADV) plus nucleoside analogues (lamivudine [LAM], telbivudine [LdT], or ETV) in patients infected with LAM- and ETV-resistant hepatitis B virus (HBV) variants. Virologic, biochemical, and serologic responses during combination therapy with ADV plus nucleoside analogues were assessed. Propensity score analysis was used to select a matched group of patients for the comparison of rescue therapy regimens. A total of 67 consecutive patients were analyzed. Complete virologic suppression was achieved in 27 patients. The overall cumulative incidence of complete virologic suppression at month 24 was 47.4%: 44.3% in the LAM or LdT plus ADV group and 51.4% in the group given ETV and ADV. There was no significant difference between these two groups (P = 0.234). The cumulative incidences of complete virologic suppression were still comparable between the two groups selected and matched using the propensity score model (P = 0.419). Virologic breakthrough was observed in 9 patients, and rtA181V substitution was newly detected in one patient. Hepatitis B e antigen (HBeAg) negativity and lower baseline HBV DNA level were associated with complete virologic suppression in univariate analysis. In multivariate analysis, lower baseline HBV DNA level remained an independent predictor. In conclusion, combination therapy with ADV plus nucleoside analogues fails to show sufficient antiviral efficacy in CHB patients with resistance to both LAM and ETV. Further study is warranted to evaluate the efficacy of a more potent tenofovir-based regimen in such patients.

Real-world application of the roadmap model in chronic hepatitis B patients with telbivudine therapy

BACKGROUND

The roadmap concept provides a strategy to maximize hepatitis B virus suppression and minimize drug resistance by add-on or switching therapy in patients with a suboptimal response at Week 24. The efficacy of this strategy in routine clinical practice remains to be validated.

OBJECTIVE

The aim of our study was to validate the roadmap concept in the treatment of chronic hepatitis B, and to investigate the virologic efficacy and kinetics of quantitative hepatitis B surface antigen (qHBsAg) during telbivudine therapy in a real-world setting.

METHODS

A prospective, cohort study enrolled 96 consecutive, treatment-naïve patients with chronic hepatitis B receiving telbivudine therapy. At Week 24, only 17 of 42 (40%) partial or inadequate responders (hepatitis B virus DNA 60-2000 and >2000 IU/mL, respectively) followed the roadmap model and consented to adefovir add-on therapy. The remaining patients continued to receive telbivudine monotherapy.

RESULTS

At Week 96, none of the patients receiving adefovir add-on therapy, and 28% of patients receiving telbivudine monotherapy, either partial or inadequate responders, developed genotypic resistance (P = 0.03). Poor early qHBsAg kinetics (an increase in qHBsAg >0.4 log IU/mL at Week 12) was the only significant predictor of genotypic resistance (adjusted hazard ratio = 13.83; 95% CI, 1.79-106.76; P = 0.01). Telbivudine monotherapy was efficacious in 94% of partial responders who did not have poor early qHBsAg kinetics, remaining free of drug resistance after 2 years.

CONCLUSIONS

The application of the roadmap model with add-on adefovir therapy prevented genotypic resistance. However, telbivudine monotherapy achieved a good response in the majority of partial responders who did not have poor early qHBsAg kinetics. Poor early qHBsAg kinetics was an early predictor of genotypic resistance at Week 96. Modification of the roadmap model to incorporate early qHBsAg kinetics may further optimize the efficacy of the treatment strategy of hepatitis B virus.

HBsAg quantification to predict natural history and treatment outcome in chronic hepatitis B patients

There is a growing interest in serum HBsAg quantification (qHbsAg). HBsAg titers are negatively correlated with liver fibrosis in HBeAg(+) patients. In HBeAg(-) HBsAg level <1000 IU/ml and HBV-DNA titer <2000 IU/ml accurately identify inactive carriers. During PEG-IFN treatment qHBsAg identifies patients with no benefit from therapy at week 12, allowing stopping or switched- "week 12 stopping rule". During nucleos(t)ide analogues the role of qHBsAg need to be clarified. In clinical practice qHBsAg is a simple and reproducible tool that may be used in association with HBV-DNA to classify patients during the natural history of HBV and to monitor therapy.

The role of HBsAg quantification for monitoring natural history and treatment outcome

Since its discovery by Blumberg in 1965, the hepatitis B virus antigen (HBsAg) is used as the fingerprint of hepatitis B infection. The HBsAg level is a reflection of the transcriptional activity of cccDNA. It is an important marker that not only indicates active hepatitis B infection but can also predict clinical and treatment outcomes. Assays for HBsAg quantification are fully automated and have high output. HBsAg titres are higher in HBe antigen (HBeAg)(+) than in HBeAg(-) patients and are negatively correlated with liver fibrosis in HBeAg(+) patients. In HBeAg(-) chronic hepatitis B, an HBsAg level <1000 IU/ml and an HBV DNA titre <2000 IU/ml accurately identify inactive carriers. During PEG-IFN treatment, HBsAg quantification is used to identify patients who will not benefit from therapy as early as week 12 on therapy, so that treatment may be stopped or switched- 'week 12 stopping rule'. With nucleos(t)ide analogues (NA), the role of HBsAg quantification must be clarified. Several studies show that baseline and on-treatment HBsAg levels might identify patients that can be treated with no subsequent risk of reactivation. In clinical practice, HBsAg quantification is a simple and reproducible tool that can be used in association with HBV DNA to classify patients during the natural history of HBV and to monitor therapy.