Clear indicators for stopping antiviral therapy in chronic hepatitis B (CHB) patients are not yet available. Since the level of hepatitis B surface antigen (HBsAg) is correlated with covalently closed circular DNA, the HBsAg titer might be a good indicator of the off-treatment response. This study aimed to determine the relationship between the HBsAg titer and the entecavir (ETV) off-treatment response.
This study analyzed 44 consecutive CHB patients (age, 44.6±11.4 years, mean±SD; men, 63.6%; positive hepatitis B envelope antigen (HBeAg) at baseline, 56.8%; HBV DNA level, 6.8±1.3 log10 IU/mL) treated with ETV for a sufficient duration and in whom treatment was discontinued after HBsAg levels were measured. A virological relapse was defined as an increase in serum HBV DNA level of >2000 IU/mL, and a clinical relapse was defined as a virological relapse with a biochemical flare, defined as an increase in the serum alanine aminotransferase level of >2 × upper limit of normal.
After stopping ETV, virological relapse and clinical relapse were observed in 32 and 24 patients, respectively, during 20.8±19.9 months of follow-up. The cumulative incidence rates of virological relapse were 36.2% and 66.2%, respectively, at 6 and 12 months, and those of clinical relapse were 14.3% and 42.3%. The off-treatment HBsAg level was an independent factor associated with clinical relapse (hazard ratio, 2.251; 95% confidence interval, 1.076–4.706;
The off-treatment HBsAg level is closely related to clinical relapse after treatment cessation. A serum HBsAg level of <2 log10 IU/mL is an excellent predictor of a sustained off-treatment response in CHB patients who have received ETV for a sufficient duration.
Chronic hepatitis B (CHB) is the leading cause of liver cirrhosis and hepatocellular carcinoma (HCC) worldwide, especially in Asia [
With the development of effective oral nucleos(t)ide analogues (NAs), prognosis of patients with CHB has improved significantly. NAs with a high potency and high genetic barrier, such as entecavir (ETV) or tenofovir disoproxil fumarate, effectively suppress HBV replication and hepatic necroinflammation, and they prevent disease progression and the development of complications [
Recent studies have identified predictors of sustained off-treatment response following NA cessation, such as younger age [
The serum HBsAg level correlates with the level of intrahepatic covalently closed circular DNA [
Consecutive CHB patients who were treated with ETV for a sufficient duration and for whom treatment was thereafter discontinued after measuring serum HBsAg levels were included in this study. Patients with a previous history of treatment with NAs before ETV treatment or patients with HCC at the time of ETV initiation were excluded. CHB was defined as a positive serological test for serum HBsAg for at least 6 months. Virologic response was defined as a decrease in serum HBV DNA to undetectable levels by PCR assays [
Clinical data including age, sex, daily alcohol consumption amount, and history of diabetes and hypertension were collected for each patient. Results of the laboratory tests (i.e., platelet count, international normalized ratio [INR], serum ALT, bilirubin, albumin, creatinine, and HBV DNA levels, and serum HBeAg/Ab) were collected at the time of ETV initiation. The duration of ETV treatment, the duration of consolidation treatment, the time of virological relapse, and the time of clinical relapse were also collected. The serum HBsAg level was measured at the end-of-treatment using the Architect HBsAg QT chemiluminescent microparticle immunoassay (Abbott Laboratories, Abbott Park, IL, USA). Laboratory tests, including serum HBV DNA and ALT levels, were performed for all patients every 3-6 months after the end-of-treatment. Patients were evaluated more often when clinically indicated. Virological relapse was defined as an increase in the serum HBV DNA level >2000 IU/mL, while clinical relapse was defined as a serum ALT level elevation >2 × upper limit of normal in addition to HBV DNA level >2000 IU/mL [
Statistical analyses were performed using SPSS software version 20.0 (SPSS Inc., Chicago, IL, USA). Data were expressed as the mean±standard deviation or number (%). The Mann-Whitney U test and chi-square test were used to compare continuous and categorical variables, respectively. The cumulative virological relapse rate was determined by the Kaplan-Meier method, and the difference between groups was determined by the log lank test. The Cox proportion hazard model was utilized to analyze factors associated with relapse. Significant factors (
Baseline characteristics are presented in
Serum HBV DNA became undetectable in all enrolled patients and the mean time to undetectable HBV DNA was 5.4±0.4 months (median, 5.5 months). Serum HBV DNA became undetectable within 3 months, 3-6 months, and >6 months in 14 (31.8%), 24 (43.4%), and 6 (13.6%) patients, respectively. The time to undetectable HBV DNA did not differ between HBeAg-positive and HBeAg-negative CHB patients (
Serum HBeAg was cleared in all HBeAg-positive patients and the mean time to HBeAg clearance was 13.6±2.7 months (median, 9.8 months). HBeAg seroconversion was achieved in 7 of the 25 HBeAg-positive patients and the mean time to HBeAg seroconversion was 57.9±6.6 months.
ETV was discontinued after 34.7±19.0 months of treatment (37.0±20.2 months and 31.6±17.4 months in HBeAg-positive and HBeAg-negative patients, respectively;
Serum HBsAg level at the end-of-treatment was 3.0±1.0 log10 IU/mL. Serum HBsAg levelswere ≤2, >2 ≤3, and > 3 log10 IU/mL in 5 (11.4%), 11 (25.0%), and 28 (63.6%) patients, respectively. The proportion of patients with an end-of-treatment HBsAg level of >3 log10 IU/mL was significantly higher in patients with positive HBeAg at baseline (20 of 25 patients, 80.0%) compared with those with negative HBeAg at baseline (8 of 19 patients, 42.1%;
During a follow-up period of 20.8±19.9 months after the end-of-treatment, virological relapse was observed in 32 patients (20 and 12 patients whose baseline HBeAg was positive and negative, respectively). The cumulative virological relapse rates at 6, 12, and 24 months were 36.2%, 66.2%, and 77.3%, respectively (
Clinical relapse occurred more frequently in the HBeAg-positive patients compared to the HBeAg-negative patients (
Of 24 patients with clinical relapse, ETV therapy was resumed after clinical relapse in all patients except one patient who was lost to follow-up after development of clinical relapse.
A univariate analysis revealed a trend of increased clinical relapse risk with positive serum HBeAg (
Multivariate analysis indicated that the serum HBsAg level was the only independent predictor of clinical relapse (β, 0.811; hazard ratio (HR], 2.251; 95% CI, 1.076-4.706;
Although various studies have evaluated the predictive efficacy of the serum HBsAg level for a sustained off-treatment response, the efficacy is not clearly defined due to discrepant results. While some studies have reported that the serum HBsAg level is a good predictor for sustained response [
There were some discrepancies between previous results and our results regarding significant predictors for sustained off-treatment response. Although the principle reasons for these discrepancies could be the different types of NAs used, different treatment discontinuation criteria, and the definition of relapse among the various studies, additional factors may be involved. First, previous studies have suggested that a younger age is a significant predictor for a sustained response [
A previous study reported that the cut-off value of the serum HBV DNA level for predicting relapse as 2×105 IU/mL; however, we could not use this cut-off value as only five patients in our study group had a serum HBV DNA level <2×105 IU/mL. We instead used the median HBV DNA level (7 log10 IU/mL) as the cut-off value in our study. Even as the clinical relapse frequency was significantly higher in patients with baseline serum HBV DNA level of ≥7 log10 IU/mL, the baseline serum HBV DNA level was not significantly associated with the development of clinical relapse, as indicated by a multivariate analysis. This could be explained by the results of the end-of-treatment serum HBsAg level according to the baseline HBV DNA level.
Various previous studies have also suggested that a sufficient duration of consolidation treatment is required to achieve a sustained off-treatment response [
There are discrepancies in the stopping rule used in this study and that of current practice guidelines [
There are several limitations in this study. First, the serum HBsAg level was not measured at the time of NA initiation as the test was not available. Analyses of baseline HBsAg level and its kinetics during treatment would have provided additional information, as a previous study has found a correlation between HBsAg kinetics and sustained off-treatment response in HBeAg-positive patients [
In conclusion, the serum HBsAg level at the end-of-treatment was closely related with off-treatment clinical relapse. Furthermore, a serum HBsAg level ≤2 log10 IU/mL is an excellent predictor for sustained off-treatment response in CHB patients who had received ETV for a sufficient duration.
This study was supported by the Research Supporting Program of the Korean Association for the Study of the Liver and by a grant from the Korean Healthcare Technology R&D Project, Ministry of Health and Welfare, Korea (HI10C2020).
alanine aminotransferase
the Asian Pacific Association for the Study of the Liver
body mass index
chronic hepatitis B
entecavir
hepatitis B e antigen
hepatitis B surface antigen
hepatitis B virus
hepatocellular carcinoma
international normalized ratio
nucleos(t)ide analogues
Cumulative incidence of virological relapse (A) and clinical relapse (B).
Cumulative incidence of clinical relapse according to the baseline serum HBeAg level (A), baseline serum HBV DNA level (B), and end-of-treatment HBsAg level (C).
Baseline characteristics of all enrolled patients with CHB according to the serum HBeAg level at the time of ETV treatment initiation
All patients (n=44) | HBeAg-positive patients (n=25) | HBeAg-negative patients (n=19) | ||
---|---|---|---|---|
Age, years | 44.6±11.4 | 44.6±13.0 | 44.7±9.3 | 0.969 |
Male, n (%) | 28 (63.6) | 14 (56.0) | 14 (73.7) | 0.227 |
BMI, kg/m2 | 23.5±2.7 | 23.6±3.2 | 23.5±2.2 | 0.936 |
Diabetes, n (%) | 4 (9.1) | 1 (4.0) | 3 (15.8) | 0.178 |
Hypertension, n (%) | 5 (11.4) | 2 (8.0) | 3 (15.8) | 0.420 |
Cirrhosis, n (%) | 17 (38.6) | 10 (40.0) | 7 (36.8) | 0.831 |
ALT, IU/mL | 260.7±423.9 | 202.0±197.6 | 338.0±605.1 | 0.297 |
Bilirubin, mg/dL | 2.4±5.4 | 2.6±6.7 | 2.2±2.8 | 0.827 |
Albumin, g/dL | 4.0±0.6 | 4.0±0.6 | 4.1±0.6 | 0.562 |
Platelet count, ×109/L | 146.0±63.6 | 152.8±55.6 | 137.0±73.5 | 0.419 |
Prothrombin time, INR | 1.2±0.3 | 1.2±0.4 | 1.1±0.2 | 0.559 |
Creatinine, mg/dL | 0.9±0.2 | 0.8±0.2 | 0.9±0.2 | 0.227 |
HBV DNA, log10 IU/mL | 6.8±1.3 | 7.2±1.0 | 6.2±1.5 | 0.011 |
Values are expressed as mean ± standard deviation or number (percent).
BMI, body mass index; ALT, alanine aminotransferase; INR, international normalized ratio; HBeAg, hepatitis B envelope antigen; HBV, hepatitis B virus.
Factors associated with the development of clinical relapse
Variable | Univariate |
Multivariate |
||
---|---|---|---|---|
HR (95% CI) | HR (95% CI) | |||
Age (years) | 1.026 (0.988-1.066) | 0.177 | ||
Male (vs. female) | 0.576 (0.254-1.303) | 0.185 | ||
BMI (kg/m2) | 0.951 (0.808-1.120) | 0.549 | ||
Diabetes (yes vs. no) | 0.295 (0.040-2.190) | 0.233 | ||
Hypertension (yes vs. no) | 1.195 (0.407-3.510) | 0.746 | ||
Liver cirrhosis (yes vs. no) | 0.528 (0.208-1.341) | 0.179 | ||
Platelet count (×109/L) | 0.998 (0.992-1.004) | 0.607 | ||
Prothrombin time, INR | 0.212 (0.023-1.982) | 0.174 | ||
Albumin (g/dL) | 1.025 (0.540-1.944) | 0.941 | ||
Bilirubin (mg/dL) | 0.822 (0.630-1.071) | 0.147 | ||
ALT (IU/L) | 1.000 (0.998-1.001) | 0.560 | ||
Creatinine (mg/dL) | 0.427 (0.045-4.034) | 0.458 | ||
HBeAg (positive vs. negative) | 2.315 (0.980-5.470) | 0.056 | 1.791 (0.703-4.564) | 0.222 |
HBV DNA (log10 IU/mL) | 1.399 (0.982-1.992) | 0.063 | 1.022 (0.671-1.557) | 0.920 |
Duration of treatment (months) | 0.997 (0.975-1.021) | 0.828 | ||
Time to HBeAg loss (months) | 0.983 (0.945-1.022) | 0.381 | ||
HBeAg seroconversion (yes vs. no) | 0.981 (0.314-3.070) | 0.974 | ||
Duration of consolidation treatment (months) | 0.995 (0.968-1.022) | 0.721 | ||
End-of-treatment HBsAg level (log10 IU/mL) | 2.606 (1.278-5.311) | 0.008 | 2.251 (1.076-4.706) | 0.031 |
HR, hazard ratio; CI, confidence interval; BMI, body mass index; INR, international normalized ratio; ALT, alanine aminotransferase; HBeAg, hepatitis B e antigen; HBV, hepatitis B virus, HBsAg, hepatitis B surface antigen.