Antiviral therapy for chronic hepatitis B: challenges in Hong Kong

Reassessing the accuracy of PAGE-B-related scores to predict hepatocellular carcinoma development in patients with chronic hepatitis B

BACKGROUND & AIMS

PAGE-B and modified PAGE-B (mPAGE-B) scores were developed to predict the risk of hepatocellular carcinoma (HCC) in patients on nucleos(t)ide analogue therapy. However, how and when to use these risk scores in clinical practice is uncertain.

METHODS

Consecutive adult patients with chronic hepatitis B who had received entecavir or tenofovir for at least 6 months between January 2005 and June 2018 were identified from a territory-wide database in Hong Kong. The performance of PAGE-B and mPAGE-B scores for HCC prediction at 5 years was assessed by area under the time-dependent receiver operating characteristic curve (AUROC), and different cut-off values of these 2 scores were evaluated by survival analysis.

RESULTS

Of 32,150 identified patients with chronic hepatitis B, 20,868 (64.9%) were male. Their mean age was 53.0 ± 13.2 years. At a median (IQR) follow-up of 3.9 (1.8-5.0) years, 1,532 (4.8%) patients developed HCC. The AUROCs (95% CI) for the prediction of HCC at 5 years were 0.77 (0.76-0.78) and 0.80 (0.79-0.81), with PAGE-B and mPAGE-B scores, respectively (p <0.001). A total of 9,417 (29.3%) patients were classified as having a low HCC risk by either PAGE-B or mPAGE-B scores; their 5-year cumulative incidence of HCC was 0.6% (0.4%-0.8%). This classification achieved a negative predictive value of 99.5% (99.4%-99.7%) to exclude patients without HCC development at 5 years. The AUROCs for the prediction of HCC with PAGE-B and mPAGE-B scores were similar at baseline and after 2 years on treatment.

CONCLUSIONS

PAGE-B and mPAGE-B scores can be applied to identify patients on antiviral therapy who are at low risk of developing HCC. These patients could be exempted from HCC surveillance due to their very low HCC risk.

LAY SUMMARY

Risk scores have been developed to predict the likelihood of patients with chronic hepatitis B developing hepatocellular carcinoma (HCC). We investigated the role of 2 such scores, PAGE-B and modified PAGE-B, in predicting the risk of HCC in 32,150 nucleos(t)ide analogue-treated patients with chronic hepatitis B. These scores identified a group of patients at very low risk of developing HCC who could therefore be exempted from HCC surveillance.

Predictive Factors for Sustained Remission after Discontinuation of Antiviral Therapy in Patients with HBeAg-positive Chronic Hepatitis B

BACKGROUND/AIMS

The optimal timing for discontinuing oral antiviral therapy in patients with HBeAg-positive chronic hepatitis B (CHB) is unclear. The aim of our study was to investigate sustained remission after stopping antiviral therapy in patients with HBeAg-positive CHB.

METHODS

We analyzed the medical records of 58 patients who were HBeAg-positive and had discontinued antiviral therapy. Antiviral therapy was discontinued after HBeAg seroconversion and HBV DNA negativity for 6-12 months with consolidation therapy. Virologic relapse was defined as an increase in serum HBV DNA >2,000 IU/mL.

RESULTS

No difference was observed between the virologic non-relapse and virologic relapse groups in baseline HBV DNA level (p=0.441) or duration of seroconversion (p=0.070). Time-to-undetectable HBV DNA during treatment was shorter in the virologic non-relapse group (29 patients) compared to the relapse group (29 patients) (4.9±2.6 vs. 13.2±12.7 months; p<0.01). Cumulative relapse rates were 12.7 in month 3, 32.7 in month 6, 47.3 in month 12, and 52.7% in month 18. We determined by multivariate analysis that the consolidation period (≥18 months, p=0.020) and early virologic response (HBV DNA <20 IU/mL) at six months during antiviral therapy (p=0.017) were significant predictors for sustained remission.

CONCLUSIONS

A consolidation period of at least 18 months and early virological response at six months during antiviral therapy were associated with sustained remission in patients with HBeAg-positive CHB after treatment.

Current developments in nucleoside/nucleotide analogues for hepatitis B

There had been remarkable development in nucleos(t)ide analogues (NAs) and evolution in treatment strategies in last 15 years. Currently, there are five NAs available for chronic hepatitis B treatment, namely lamivudine, telbivudine and entecavir (nucleoside analogues), adefovir dipivoxil and tenofovir disoproxil fumarate (nucleotide analogues). The advantages of relatively infrequent side effects and easy administration per oral make NAs popular treatment options. The major drawback of earlier generation NAs is the risk of emergence of drug resistance. Current international guidelines recommend the use of more potent agents with high genetic barriers to resistance including entecavir and tenofovir as first line chronic hepatitis B treatment. However, there is no consensus regarding the subsequent treatment regimens in patients with suboptimal responses to NAs. De novo combination therapy of two NAs, response-guided therapy and roadmap concept in NAs with subsequent switch or add-on therapy can also potentially improve treatment efficacy and avoid resistance.

Efficacy of entecavir switch therapy in chronic hepatitis B patients with incomplete virological response to telbivudine

BACKGROUND

The roadmap concept suggests the use of on-treatment HBV DNA to guide treatment strategy of chronic hepatitis B patients treated by telbivudine. Our aim was to validate the roadmap approach of entecavir switch therapy in patients with incomplete response to telbivudine.

METHODS

Consecutive chronic hepatitis B patients on telbivudine monotherapy were studied. Incomplete virological response was defined as detectable HBV DNA after 6-12 months of treatment. Maintained virological response was defined as undetectable HBV DNA until the last follow-up.

RESULTS

Among the 79 patients on telbivudine, 39 (49%) had undetectable HBV DNA after 6-12 months of telbivudine treatment and 40 (51%) had incomplete virological response. In total, 33 incomplete responders switched to entecavir at 11 months (6-23), and 26 (79%) achieved maintained virological response after 25 months (4-46). Low HBV DNA level before switch therapy was the independent factor associated with maintained virological response to entecavir (P=0.01). A total of 24 of 25 (96%) patients with HBV DNA<2,000 IU/ml, versus 2 of 8 (25%) patients with HBV DNA≥2,000 IU/ml, had maintained virological response after switching to entecavir. Although rtM204I and/or rtL180M was detected in 3 of 7 patients with incomplete virological response to entecavir, none of the patients with HBV DNA<2,000 IU/ml during telbivudine treatment harboured these amino acid substitutions.

CONCLUSIONS

Roadmap approach using entecavir switch at month 6-12 among incomplete responders to telbivudine is recommended if the HBV DNA is <2,000 IU/ml at the time of switching.

Use of antiviral therapy in surveillance: impact on outcome of hepatitis B-related hepatocellular carcinoma

BACKGROUND

Antiviral therapy for hepatitis B virus (HBV) infection is frequently prescribed for patients with chronic HBV infection during surveillance for hepatocellular carcinoma (HCC). In patients who subsequently develop HCC, the impact of antiviral therapy on the outcome of HCC remains unclear.

AIMS

We aimed to study the impact of antiviral therapy on the survival of patients who developed HCC.

METHODS

From two prospective surveillance cohorts, the use of antiviral therapy for patients with HCC was retrospectively reviewed. We compared the overall survival, liver function and tumour characteristics between patients with and without antiviral therapy during surveillance. Multivariate analysis was conducted to determine the independent prognostication of antiviral therapy.

RESULTS

During a median follow-up of 10.1 years of 1429 patients, 148 cases of HCC were diagnosed and followed up for a median of 5.7 years. Twenty-nine patients were given antiviral therapy during surveillance and continued treatment after diagnosis of HCC. The median survival of this group of patients was better than the rest of cohorts (hazard ratio: 0.472; 95% CI: 0.25-0.89; P = 0.0191). Use of antiviral therapy remained an independent prognostic factor after adjustment for demographic factors and tumour staging on multivariate analysis. Exploratory analysis revealed that patients who commenced antiviral therapy during surveillance had lower HBV DNA, lower serum alanine transaminase, better hepatic reserves and higher rate of local treatment at diagnosis of HCC.

CONCLUSION

This study provides evidence that commencement of antiviral therapy during the surveillance period is associated with improvement in overall survival in HBV-related HCC.

Predictors of relapse in chronic hepatitis B after discontinuation of anti-viral therapy

BACKGROUND

Optimal duration of anti-viral therapy in chronic hepatitis B virus (HBV) infection remains unclear.

AIM

To investigate factors that could predict relapse after stopping anti-viral agents.

METHODS

Chronic hepatitis B patients who were treated with anti-viral agents (lamivudine, adefovir, entecavir) and have stopped the treatment were recruited. Anti-viral agents were stopped according to the recommendations of the Asian Pacific Association for the Study of the Liver. Virological relapse was defined as an increase in serum HBV DNA to >1000 copies/mL after discontinuation of treatment.

RESULTS

Eighty-four (69 treatment naïve and 15 lamivudine resistant) patients were eligible for this study. Thirty-seven patients developed virological relapse at 4.3 ± 2.9 (range 1-11) months after discontinuation of therapy. The 1-year cumulative probability of virological relapse was 42% and 47% in HBeAg (hepatitis B e antigen)-positive (n = 41) and HBeAg (hepatitis B e antigen)-negative (n = 43) patients, respectively. On multivariate analysis by Cox proportional hazard model, pre-existing lamivudine resistance, delayed suppression of HBV DNA to undetectable level during anti-viral therapy and to a higher HBsAg (hepatitis B surface antigen) level at the end of treatment were associated with virological relapse. Twelve of the 15 (80%) lamivudine resistant patients developed virological relapse. Among the 11 treatment naïve patients who had HBsAg ≤ 2 log IU/mL at the end of treatment, 1 (9%) of them had virological relapse.

CONCLUSIONS

Treatment cessation among lamivudine resistant patients is associated with high risk of virological relapse. Serum HBsAg level at the end of treatment and rate of HBV DNA suppression can provide supplementary information to guide the timing of stopping anti-viral drugs.

Entecavir treatment in patients with severe acute exacerbation of chronic hepatitis B

BACKGROUND & AIMS

Severe acute exacerbation of chronic hepatitis B is a unique clinical presentation with significant morbidity and mortality. Lamivudine was used in most previous studies, but the drug was limited by the development of resistance. Our objective is to study the safety and efficacy of entecavir in patients with severe acute exacerbation.

METHODS

Consecutive patients with severe acute exacerbation of chronic hepatitis B were recruited from 1998 to 2009. All patients had serum alanine aminotransferase and bilirubin increased beyond 10 and 3 times the upper limit of normal, respectively. The primary endpoint was overall mortality at week 48. Virological and biochemical responses were also studied.

RESULTS

Thirty-six patients and 117 patients were treated with entecavir and lamivudine, respectively. By week 48, 7 (19%) patients in the entecavir group and 5 (4%) patients in the lamivudine group died (adjusted hazard ratio 5.1, 95% confidence interval 1.5-17.2, p=0.010). Similarly, the entecavir group had higher liver-related mortality (adjusted hazard ratio 4.0, 95% confidence interval 1.0-15.7, p=0.044). Despite a lower prevalence of cirrhosis, more patients in the entecavir group developed prolonged jaundice, hepatic encephalopathy, and ascites. Entecavir resulted in more rapid and complete viral suppression, with 71% of patients achieving undetectable hepatitis B virus (HBV) DNA at week 48, compared to 40% in the lamivudine group (p=0.007). However, rapid HBV DNA reduction at week 4 was associated with prolonged jaundice.

CONCLUSIONS

Entecavir treatment is associated with increased short-term mortality in patients with severe acute exacerbation of chronic hepatitis B but achieves better virological response in the long run.

Chronic hepatitis B in Asia-new insights from the past decade

Chronic hepatitis B virus (HBV) infection is a major health problem in the Asia-Pacific region. In the past decade, much progress has been made in the understanding and management of this disease. The introduction of universal vaccination has significantly reduced the incidence of perinatal infection in most Asia-Pacific countries. As the majority of the adult population have not been immunized at birth, we are still facing a large population of young HBV-infected patients in the coming two decades. The study of long-term longitudinal databases has provided deeper insight into the clinical significance of HBV DNA suppression, hepatitis B e antigen (HBeAg) seroconversion and hepatitis B surface antigen (HBsAg) seroclearance in chronic hepatitis B. With a better understanding on the natural history of HBV infection, one can now stratify the risk of chronic hepatitis B patients for adverse clinical outcomes and use this to individualize management. The introduction of non-invasive assessment of liver fibrosis can potentially reduce the necessity of liver biopsy. There have also been great advances in the development of antiviral therapy in the past decade. However, the high cost of HBV antiviral drugs poses major challenges to health authorities in many Asia-Pacific countries. Properly performed cost-effective analysis and understanding on the best timing of stopping antiviral drugs will be important to facilitate the most appropriate allocation of resources.

A longitudinal study on the natural history of serum hepatitis B surface antigen changes in chronic hepatitis B

Serum hepatitis B surface antigen (HBsAg) quantification has been suggested to reflect the concentration of covalently closed circular DNA in the liver. We aimed to investigate the HBsAg levels at different stages of chronic hepatitis B and the changes in HBsAg level during the natural progression of disease. One hundred seventeen untreated patients with chronic hepatitis B were studied with longitudinal follow-up for 99 ± 16 months. HBsAg quantification was performed at the first visit, the last visit, and three visits at each quartile during the follow-up. At the first visit, HBsAg level was higher among patients who were hepatitis B e antigen (HBeAg)-positive (N = 49) than those who were HBeAg-negative (N = 68) (4.01 ± 0.91 log IU/mL versus 2.73 ± 1.25 log IU/mL, P < 0.001). HBsAg level was persistently high at approximately 5 log IU/mL among patients in the immune tolerance phase (N = 7). The HBsAg levels among patients with HBeAg-positive active disease (N = 25) or sustained HBeAg seroconversion (N = 17) were comparable at approximately 3-4 log IU/mL. The HBsAg levels among patients who were HBeAg-negative tended to be higher among patients with active (N = 46) than those with inactive disease (N = 22). The median HBsAg levels decreased in HBeAg-negative patients with active and inactive disease by 0.041 log IU/mL/year and 0.043 log IU/mL/year, respectively. Twenty-two (17%) patients had HBsAg reduction >1 log IU/mL at the last visit; most of them showed reduced hepatitis B virus DNA, and eight had HBsAg loss.

CONCLUSION

HBsAg remained stable in HBeAg-positive patients and tended to reduce slowly in HBeAg-negative patients. Reduction of HBsAg for >1 log IU/mL could reflect improved immune control.