Serum HBsAg changes in HBeAg positive chronic hepatitis B patients with continuous viral load reductions during treatment with adefovir or peg-interferon-alpha-2a

Loss of HBsAg and antiviral treatment: from basics to clinical significance

Accurate prediction of the sustained virological response (SVR) to antiviral therapy against chronic hepatitis B (CHB) is still a crucial problem needing profound investigation. In recent years, quantification of hepatitis B surface antigen (HBsAg), a reliable predictor of SVR and an ideal endpoint of treatment, has attracted increasing attention. Serum HBsAg titer may reflect the level of intrahepatic hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in most patients, and vary with natural phases of chronic HBV infection, genotypes and variants, antiviral therapy, and other related factors. Serum HBsAg <200 IU/mL or yearly reduction ≥0.5 log10IU/mL may be the optimum cut-off values for prediction of the chance of spontaneous seroclearance of HBsAg. Serum HBsAg <1,000 IU/mL with HBV DNA <2,000 IU/mL may identify most of the inactive HBV carriers from active HBeAg(-) hepatitis. Interferon-based therapy can lead to more significant HBsAg decline than therapy based on nucleoside and/or nucleotide analogues. Different patterns or kinetics of HBsAg decline during therapy are related to different probabilities of SVR. A low HBsAg level, <3,000 IU/mL at baseline, or HBsAg level, <1,500 IU/mL at week 12, or a rapid on-treatment HBsAg decline of ≥0.5 log10IU/mL at week 12, may predict higher probability of SVR. However these cut-off values must be further validated for larger cohort of patients across genotypes worldwide. Incorporation of serum HBsAg level, HBeAg status, HBV DNA load, HBV genotypes, and other related factors might help establish new concept of more practical "response-guided treatment (RGT)" rules for antiviral therapy.

Quantitative hepatitis B surface antigen titres in Chinese chronic hepatitis B patients over 4 years of entecavir treatment

BACKGROUND

The clinical value of quantitative hepatitis B surface antigen (qHBsAg) titre in patients taking nucleotide/nucleoside analogues (NAs) is still controversial. This study aims to investigate the dynamic changes of qHBsAg titres and their significance for predicting virological response (VR) and serological response (SR) to long-term entecavir (ETV) treatment.

METHODS

A total of 48 ETV-naive patients were enrolled and followed prospectively for 4 years, 32 of whom were hepatitis B e antigen (HBeAg)-positive at baseline. Serum alanine aminotransferase (ALT), qualitative HBV serological markers and HBV DNA were detected; qHBsAg titres were measured using Elecsys(®) HBsAg II Quant Assay (Roche Diagnostics, Penzberg, Germany).

RESULTS

The mean baseline HBV DNA and qHBsAg were 7.51 log10 copies/ml and 3.78 log10 IU/ml, respectively. After 48 months of ETV treatment, the rates of VR (<291 copies/ml), ALT normalization and SR (HBeAg/antibody to HBeAg [anti-HBe]) were 89.6% (43/48), 89.6% (43/48) and 34.4% (11/32), respectively. There was a decrease in qHBsAg titres from baseline to month 48, ranging from 3.78 to 3.10 log10 IU/ml. The greatest decrease of qHBsAg was observed in the first 3 months of treatment (0.47 log10 IU/ml), which was significantly correlated with corresponding HBV DNA decreases (3.89 log10 copies/ml; P=0.032). By using receiver operating characteristic (ROC) curve analysis, qHBsAg titres at baseline (area under the curve [AUROC]=0.647) and 3 months after treatment (AUROC=0.586) had poor power in predicting 48-month VR; qHBsAg titres at baseline (AUROC=0.779) and 3 months after ETV treatment (AUROC=0.658) had poor power in predicting 48-month SR in patients who were HBeAg-positive at baseline. Additionally, the decrease of qHBsAg in the first 3 months of treatment also had poor power in predicting either 48 month VR or SR.

CONCLUSIONS

ETV is efficacious in NA-naive patients, and qHBsAg titres decreased significantly in the first 3 months of ETV treatment. However, qHBsAg titre was not a good predictor of 4-year VR and HBeAg/anti-HBe SR in this cohort.

Elecsys hepatitis B surface antigen quantitative assay: performance evaluation and correlation with hepatitis B virus DNA during 96 weeks of follow-up in chronic hepatitis B patients

Background

Treatment for chronic hepatitis B aims to suppress virus replication and virus sequestration in hepatocytes. Covalently closed circular (ccc) DNA is the template for transcription of viral genes and is responsible for viral persistence. However, limited data are available for quantification of hepatitis B surface antigen (HBsAg) in Korea.

Methods

We evaluated the Elecsys HBsAg II quant assay (Roche Diagnostics, USA) for within-run, between-run, and between-day precisions, linearity, carryover, and clinical specificity. In total, 156 serum samples were evaluated for correlation between HBsAg and hepatitis B virus (HBV) DNA. Serial samples were obtained from 10 patients at 0, 12, 24, 48, 72, and 96 weeks during follow-up.

Results

The assay detected HBsAg in a linear range of 0.5-48,696 IU/mL. Within-run, between-run, and between-day CVs were 2.9-4.1%, 0-1.5%, and 1.5-4.9%, respectively. Cross-reactivity between potentially interfering substances was absent, and the carryover rate was 0.00002%. The correlation of measurements between the Elecsys assay and HBV DNA PCR was weak (r=0.438, P=0.002). For predicting virologic response, cutoff values of 10,275 IU/mL and 3,846 IU/mL at 12 and 24 weeks after treatment initiation showed positive predictive values of 77.1% and 85% and negative predictive values of 84.6% and 50%, respectively.

Conclusions

The Elecsys HBsAg II quant assay showed good performance for precision, linearity, carryover rate, and specificity. HBsAg level at baseline, 12 weeks, and 24 weeks after treatment initiation can predict virologic response, and the assay can be used for HBsAg quantification in clinical practice.

[Quantification of hepatitis B virus HBsAg: clinical implications]

The surface antigen of hepatitis B virus (HBsAg) is the main serological marker of HBV infection since its discovery almost 50 years ago. Currently the quantification of HBsAg has acquired special relevance as there are commercial tests to measure its levels. Several studies have shown that in patients treated with pegylated interferon alfa the fall of HBsAg levels predicts the loss of HBsAg and persistent virologic response. The role of the quantification of HBsAg in the treatment with nucleoside analogues is still not well understood and requires further studies.

Pretreatment HBeAg level and an early decrease in HBeAg level predict virologic response to entecavir treatment for HBeAg-positive chronic hepatitis B

There are few reports on hepatitis B e antigen (HBeAg) titres during nucleos(t)ide analogues treatment. We investigated the changes in HBeAg levels in patients treated with entecavir and the usefulness of HBeAg quantification for predicting antiviral response. Ninety-five consecutive HBeAg-positive patients treated with entecavir for more than 48 weeks were enrolled. Serum levels of hepatitis B surface antigen (HBsAg), HBeAg and HBV DNA were assessed at 4-week intervals to week 24 and thereafter at 12-week intervals. Virologic response (Y1VR) was defined as an undetectable HBV DNA level at week 48 of therapy. During 48 weeks, HBeAg and HBV DNA level decreased significantly in a biphasic manner and HBsAg level tended to decease. Fifty-three patients (55.8%) attained Y1VR. Pretreatment HBeAg levels were significantly lower in the Y1VR group than in no Y1VR group. At week 4 and 12 of therapy, 25% and 41.4% of patients showed a decrease of HBeAg levels with >0.5 log(10) and >1.0 log(10) from baseline, respectively. These patients achieved more Y1VR than those with less decrease of HBeAg levels (97.7%vs 22.2% and 86.2%vs 29.3%, respectively). HBeAg level at week 12 had higher predictive values for Y1VR than HBV DNA level. Multivariate analysis revealed that a pretreatment HBeAg level of <360 PEIU/mL and the reduction in HBeAg level >1.0 log(10) at week 12 were associated with Y1VR. These results suggest that pretreatment HBeAg level and an early decrease in HBeAg level are useful measurements for predicting one-year virologic response during entecavir treatment.

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

BACKGROUND

We aimed to investigate factors associated with serum hepatitis B surface antigen (HBsAg) levels and its kinetics under lamivudine treatment in chronic hepatitis B patients.

METHODS

HBsAg levels were measured with the Architect HBsAg assay (Abbott laboratories, Abbott Park, IL, USA) in genotype B (HBV/B) or C (HBV/C) patients (n=218). Early HBsAg kinetics in 86 hepatitis B e antigen (HBeAg)-positive patients and long-term HBsAg changes in 45 patients with rapid and sustained viral suppression were further analysed.

RESULTS

Mean HBsAg levels were higher in male (n=181) than in female (n=37) patients (3.59 versus 3.23 log(10) IU/ml; P=0.036), and higher in 121 HBV/B than in 97 HBV/C patients (3.68 versus 3.34 log(10) IU/ml; P=0.006). In addition to HBV DNA loads (P<0.001), male gender (P=0.012) and HBV/B infection (P=0.035) were independently associated with higher HBsAg levels in antiviral-naive patients. HBsAg increases (0.00-0.87 log(10)) were found in 28/86 patients who obtained viral suppression under 12 weeks of lamivudine therapy. Higher baseline HBsAg levels (P=0.046), HBV/B infection (P=0.007) and faster HBV DNA declines (P=0.006) independently contributed to greater HBsAg decreases under 12 weeks treatment. An apparent dissociation between HBsAg and HBV DNA changes were found in 14/45 patients with rapid and sustained viral suppression, who had low baseline HBsAg levels and predominant HBV/C infection.

CONCLUSIONS

HBV/B and male gender were associated with higher HBsAg levels in antiviral-naive patients. Higher baseline HBsAg levels and HBV/B infection contributed to greater early HBsAg declines in HBeAg-positive patients, and might correlate with discordance between HBsAg and HBeAg or HBV DNA under long-term lamivudine treatment.

Quantitative hepatitis B surface antigen levels in patients with chronic hepatitis B after 2 years of entecavir treatment

OBJECTIVES

The role of quantitative hepatitis B surface antigen (HBsAg) levels in patients receiving oral antiviral therapy is controversial. We aimed to determine the HBsAg response in chronic hepatitis B patients treated with entecavir 0.5 mg daily for 2 years.

METHODS

A total of 166 patients were included. Liver biochemistry, hepatitis B virus (HBV) serological markers, HBV DNA, and quantitative HBsAg levels were performed at baseline, year 1, and year 2 after commencing entecavir. Additional HBsAg levels were measured at 12 and 24 weeks in patients with available sera.

RESULTS

In all, 68 patients were hepatitis B e-antigen (HBeAg) positive. Age, HBV DNA, and alanine aminotransferase (ALT) were significantly correlated with HBsAg levels at baseline (r=-0.429, 0.607, and 0.254, respectively, all P<0.05). The correlation with HBV DNA and ALT levels was reduced by entecavir treatment, and was lost after 2 years of treatment. There was an overall decline in HBsAg levels from baseline to year 1 to year 2 (3,377.4 vs. 2,316.5 vs. 1,903.0 IU/ml, respectively, P<0.001). However, at year 2, 102 patients (61%) had no significant changes (<0.5 log difference), 50 (30%) had significant decline (≥0.5 log decrease), whereas 14 (9%) had significant increase (≥0.5 log increase). Of the patients, 151 (91%) had undetectable HBV DNA; 25 (37%) underwent HBeAg seroconversion. Neither HBsAg at baseline nor early decline at weeks 12 or 24 was predictive of HBeAg seroconversion at 2 years.

CONCLUSIONS

Despite HBV DNA suppression, the majority did not show significant decline in HBsAg levels. Early decline of HBsAg levels at 12/24 weeks was not associated with HBV DNA suppression or HBeAg seroconversion.

Kinetics of hepatitis B surface antigen decline during 3 years of telbivudine treatment in hepatitis B e antigen-positive patients

The impact of prolonged direct antiviral therapy on hepatitis B surface antigen (HBsAg) levels in patients with chronic hepatitis B is poorly understood. We quantitatively assessed serum HBsAg levels during 3 years of telbivudine treatment, as well as their relationship with virologic and biochemical characteristics in 162 hepatitis B e antigen-positive patients who maintained undetectable serum hepatitis B virus (HBV) DNA long-term. Telbivudine treatment progressively reduced serum HBsAg levels (mean ± SD) from baseline (3.8 ± 0.6 log₁₀ IU/mL) to treatment week 24 (3.4 ± 0.7 log₁₀ IU/mL), treatment year 1 (3.3 ± 0.8 log₁₀ IU/mL), and treatment year 3 (3.0 ± 1.4 log₁₀ IU/mL) (P <0.0001). In this patient population, HBsAg loss was observed in nine (6%) of 162 patients through year 3. During the first year of treatment, three patterns of HBsAg decline were observed: rapid (≥ 1 log₁₀ IU/mL) in 32 patients, slow (0-1 log₁₀ IU/mL) in 74 patients, and steady levels in 56 patients. These findings were associated with different likelihoods of HBsAg loss during long-term telbivudine therapy. Eight of 32 patients with rapid HBsAg decline versus none of 56 patients with steady HBsAg levels achieved HBsAg loss at year 3 (P = 0.0024). HBV genotype was a significant determinant for HBsAg kinetics, with the fastest decline in genotype A patients. In patients with subsequent HBsAg loss, viral antigens were already undetectable in liver biopsy samples after 1 year of treatment. This was associated with markedly enhanced antiviral T cell reactivity.

CONCLUSION

In patients who have effective suppression of viral replication during telbivudine treatment, a rapid decline in serum HBsAg levels during the first year may identify those with a greater likelihood of achieving HBsAg clearance.

[Comparison of nine different qualitative HBsAg assay kits]

BACKGROUND

Qualitative hepatitis B surface antigen (HBsAg) assay kits are still commonly used in Korea where hepatitis B virus (HBV) infection is endemic. The accurate determination of HBsAg plays a crucial role in the diagnosis and prevention of HBV infection, especially in endemic areas. The aim of this study was to compare the detection sensitivities of 9 qualitative HBsAg assay kits.

METHODS

Seven pooled sera with HBsAg concentration ranging from 0.14 IU/mL to 29.96 IU/mL were prepared. The HBsAg concentration of each pooled serum was determined by a quantitative HBsAg assay, Architect HBsAg (Abbott Laboratories, Ireland). The fully automated immunoassay kits included Elecsys HBsAg (Roche Diagnostics, Germany) and Immulite 2000 HBsAg (DPC, USA) and the rapid tests included 5 immunochromatographic assay (ICA) kits and 2 reverse passive hemagglutination assay (RPHA) kits.

RESULTS

Elecsys HBsAg (Roche Diagnostics) showed positive result in pooled serum with HBsAg concentration of 0.14 IU/mL, but Immulite 2000 HBsAg (DPC) showed negative result in the same concentration. Although ICA kits showed variable results among different assay kits, all of them showed negative results in pooled sera with HBsAg concentration of < or = 1.89 IU/mL. Two RPHA kits showed negative results in pooled sera with HBsAg concentration of < or = 7.98 IU/mL.

CONCLUSIONS

Although ICAs were more sensitive than RPHAs, they had variable sensitivities for HBsAg and were less sensitive than the automated immunoassay kits. Therefore, ICAs and RPHAs should be used with caution in the screening tests for HBsAg and their sensitivities need to be improved.

Predictors of treatment response in chronic hepatitis B

The ultimate goal of treatment for chronic hepatitis B is to reduce liver-related complications and mortality. Sustained hepatitis B e antigen (HBeAg) seroconversion and hepatitis B surface antigen (HBsAg) clearance 6-12 months after stopping treatment are the short-term surrogate outcomes for interferon or peginterferon therapy. As most patients require long-term nucleos(t)ide analogue treatment, which also has the risk of drug resistance in the case of incomplete viral suppression, maintained hepatitis B virus (HBV) DNA suppression to an undetectable level is the appropriate surrogate outcome. Because no antiviral treatment is perfect, it is desirable for treatment response to be predicted and the treatment regimen modified accordingly. At baseline, high ALT and low HBV DNA levels can predict response to both (peg)interferon and nucleos(t)ide analogues. Genotype A HBV responds best to peginterferon but HBV genotype has no predictive value for nucleos(t)ide analogue treatment. HBV DNA is a good on-treatment predictor of response for nucleos(t)ide analogues but not for (peg)interferon. The data supporting the use of quantitative HBsAg and HBeAg to predict response to peginterferon is stronger than that for nucleos(t)ide analogues. In conclusion, predictors of response are useful to provide the most appropriate antiviral therapy to the most suitable patients, in order to achieve the best response and improve the clinical outcome of chronic hepatitis B patients.