Long-term continuous entecavir therapy in nucleos(t)ide-naïve chronic hepatitis B patients

EASL 2017 Clinical Practice Guidelines on the management of hepatitis B virus infection

Hepatitis B virus (HBV) infection remains a global public health problem with changing epidemiology due to several factors including vaccination policies and migration. This Clinical Practice Guideline presents updated recommendations for the optimal management of HBV infection. Chronic HBV infection can be classified into five phases: (I) HBeAg-positive chronic infection, (II) HBeAg-positive chronic hepatitis, (III) HBeAg-negative chronic infection, (IV) HBeAg-negative chronic hepatitis and (V) HBsAg-negative phase. All patients with chronic HBV infection are at increased risk of progression to cirrhosis and hepatocellular carcinoma (HCC), depending on host and viral factors. The main goal of therapy is to improve survival and quality of life by preventing disease progression, and consequently HCC development. The induction of long-term suppression of HBV replication represents the main endpoint of current treatment strategies, while HBsAg loss is an optimal endpoint. The typical indication for treatment requires HBV DNA >2,000IU/ml, elevated ALT and/or at least moderate histological lesions, while all cirrhotic patients with detectable HBV DNA should be treated. Additional indications include the prevention of mother to child transmission in pregnant women with high viremia and prevention of HBV reactivation in patients requiring immunosuppression or chemotherapy. The long-term administration of a potent nucleos(t)ide analogue with high barrier to resistance, i.e., entecavir, tenofovir disoproxil or tenofovir alafenamide, represents the treatment of choice. Pegylated interferon-alfa treatment can also be considered in mild to moderate chronic hepatitis B patients. Combination therapies are not generally recommended. All patients should be monitored for risk of disease progression and HCC. Treated patients should be monitored for therapy response and adherence. HCC remains the major concern for treated chronic hepatitis B patients. Several subgroups of patients with HBV infection require specific focus. Future treatment strategies to achieve 'cure' of disease and new biomarkers are discussed.

Long-term real-world entecavir therapy in treatment-naïve hepatitis B patients: base-line hepatitis B virus DNA and hepatitis B surface antigen levels predict virologic response

BACKGROUND/AIMS

Entecavir is a potent nucleoside analogue with high efficacy and barrier for resistance. We aimed to investigate the long-term efficacy and viral resistance rate of entecavir and explore the factors associated with virologic response, including quantitative hepatitis B surface antigen (qHBsAg) levels.

METHODS

One thousand and nine treatment-naïve chronic hepatitis B (CHB) patients were evaluated for cumulative rates of virologic response, biochemical response, and entecavir mutations. The role of baseline qHBsAg for virologic response was assessed in 271 patients with qHBsAg prior to entecavir treatment.

RESULTS

The median duration of entecavir treatment was 26.5 months. The cumulative rate of virologic response at years 1, 3, and 5 were 79.0%, 95.6%, and 99.4%, respectively. The cumulative rate of entecavir resistance was 1.0% and 2.1% in years 3 and 5. Multivariate analysis identified baseline hepatitis B e antigen (HBeAg) negative status (p < 0.001) and lower hepatitis B virus (HBV) DNA (p < 0.001) as predictors of virologic response. Lower qHBsAg was an independent predictor of virologic response in patients with baseline qHBsAg. There were no serious adverse events during treatment.

CONCLUSIONS

Long-term entecavir treatment of nucleos(t)ide-naïve CHB patients was associated with an excellent virologic response and a low rate of entecavir-resistant mutations at 5 years. Baseline HBV DNA load, qHBsAg levels, and HBeAg status were predictors of virologic response during entecavir treatment.

Efficacy of tenofovir-based rescue therapy for chronic hepatitis B patients with resistance to lamivudine and entecavir

BACKGROUND/AIMS

Tenofovir disoproxil fumarate (TDF) monotherapy for 48 weeks provided a virological response comparable to that of TDF and entecavir (ETV) combination therapy in patients infected with ETV-resistant hepatitis B virus (HBV). Little long-term data in routine clinical practice are available regarding the optimal treatment of patients with ETV-resistant HBV.

METHODS

We investigated the long-term antiviral efficacy of combination therapy of TDF+lamivudine (LAM) or TDF+ETV compared to that of TDF monotherapy in 73 patients with resistance to both LAM and ETV.

RESULTS

Patients were treated with TDF monotherapy (n=12), TDF+LAM (n=19), or TDF+ETV (n=42) for more than 6 months. The median duration of TDF-based rescue therapy was 37 months. Virologic response (VR) was found in 63 patients (86.3%). The rates of VR among the three groups (TDF monotherapy, TDF+LAM, and TDF+ETV) were not statistically different (log-rank P=0.200) at 12 months (59.3%, 78.9%, and 51.8%, respectively) or at 24 months (88.4%, 94.7%, and 84.2%). In addition, treatment efficacy of TDF-based combination or TDF monotherapy was not statistically different with ETV-resistant strains or exposure to other antiviral agents. In multivariate analysis, only lower baseline HBV DNA level was an independent predictor for VR (hazard ratio, 0.723; 95% confidence interval, 0.627-0.834; P<0.001).

CONCLUSIONS

TDF monotherapy was as effective as combination therapy of TDF+LAM or TDF+ETV in maintaining long-term viral suppression in chronic hepatitis B patients with resistance to both LAM and ETV. HBV DNA level at the start of TDF rescue therapy was the only independent predictor of subsequent VR.

Efficacy of long-term tenofovir-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs

BACKGROUND

Few studies have investigated the efficacy of long-term tenofovir disoproxil fumarate (TDF)-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs.

METHODS

We retrospectively analyzed 40 Japanese patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs who received TDF-based rescue therapy [TDF monotherapy, TDF plus lamivudine (LAM) combination therapy, or TDF plus entecavir (ETV) combination therapy] followed up for a median of 45 months (range 14-99 months). Viral response, changes in hepatitis B surface antigen levels from the baseline, and viral breakthrough during therapy were analyzed.

RESULTS

The proportion of patients with undetectable serum hepatitis B virus (HBV) DNA levels (less than 2.1 log copies per milliliter) (viral response) during TDF-based rescue therapy was 68, 78, 85, 88, 83, 81, 88, and 100 % at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4 years respectively. There were no differences in the viral response rate between the TDF plus LAM group and the TDF plus ETV group. The mean reduction from the baseline in hepatitis B surface antigen levels in patients with LAM-resistant HBV was greater than the reductions in patients with adefovir dipivoxil (ADV)-resistant or ETV-resistant HBV at 2 and 3 years (P = 0.024, and P = 0.025 respectively). However, two patients with ADV- or ETV-resistant HBV at the baseline developed viral breakthrough during TDF-based rescue therapy.

CONCLUSIONS

Long-term therapy with a TDF-based rescue regimen demonstrated high viral suppression in patients in whom LAM plus ADV combination therapy, ETV plus ADV combination therapy, or ETV monotherapy had failed. However, patients with ADV- or ETV-resistant HBV at the baseline may develop viral breakthrough and resistance, and careful follow-up is advised.

Alpha-interferon treatment in hepatitis B

Pegylated interferon-α (PEG-IFN-α) is a first line option in the treatment of chronic hepatitis B. Compared with nucleos(t)ide analogues (NAs), therapy with PEG-IFN-α has the advantages of finite treatment duration and higher rates of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) seroconversion, but the disadvantage of greater adverse effects. Choosing PEG-IFN-α requires careful evaluation of the likelihood of achieving a sustained off-treatment response. Sustained off-treatment response with PEG-IFN-α can be predicted by baseline factors in HBeAg positive disease. These include genotype A or B, low viral load, high alanine aminotransferase (ALT), older age and female gender. On the other hand, no pre-treatment factors have been identified that can reliably predict response in HBeAg negative disease. Using on-treatment quantitative HBsAg levels, failure of a long term response can be identified with high negative predictive value (NPV). However, no combination of on treatment parameters have been identified so far that can precisely forecast successful treatment. Up until recently, there was little evidence supporting the use of combining PEG-IFN with NAs. The addition of PEG-IFN in patients who already have viral suppression with NAs therapy appears superior to continuing NAs alone in achieving a sustained response. Also, tenofovir disoproxil fumarate (TDF) in combination with PEG-IFN has been reported to enable significantly higher HBsAg loss than with either monotherapy alone. This occurred in both HBeAg positive and negative patients across all genotypes. In spite of recent developments, rates of HBsAg loss are still only in the order of 10% and so cure remains elusive. Further research is required to identify the optimal combination or sequential therapy regimen, and the subgroups with the highest rates of response so that they can be targeted.

Effectiveness and Safety of Entecavir or Tenofovir in a Spanish Cohort of Chronic Hepatitis B Patients: Validation of the Page-B Score to Predict Hepatocellular Carcinoma

BACKGROUND

Long-term antiviral therapy has resulted in viral suppression and biochemical response in chronic hepatitis B, although the risk of hepatocellular carcinoma has not been abolished. The Page-B score could be useful to estimate the probability of HCC.

AIMS

To analyze the effectiveness and safety of entecavir or tenofovir for more than 4 years and the usefulness of Page-B score in the real-world setting.

METHODS

Analysis of Caucasian chronic hepatitis B subjects treated with entecavir or tenofovir from the prospective, multicenter database CIBERHEP.

RESULTS

A total of 611 patients were enrolled: 187 received entecavir and 424 tenofovir. Most were men, mean age 50 years, 32% cirrhotic and 16.5% HBeAg-positive. Mean follow-up was 55 (entecavir) and 49 (tenofovir) months. >90% achieved HBV DNA <69 IU/mL and biochemical normalization by months 12 and 36, respectively. Cumulative HBeAg loss and anti-HBe seroconversion were achieved by 33.7 and 23.8%. Four patients lost HBsAg; three HBeAg-positive. Renal function remained stable on long-term follow-up. Fourteen (2.29%) developed HCC during follow-up all of them with baseline Page-B ≥10. Nine were diagnosed within the first 5 years of therapy. This contrasts with the 27 estimated by Page-B, a difference that highlights the importance of regular HCC surveillance even in patients with virological suppression.

CONCLUSIONS

Entecavir and tenofovir achieved high biochemical and virological response. Renal function remained stable with both drugs. A Page-B cut-off ≥10 selected all patients at risk of HCC development.

Comparison of FIB-4 index and aspartate aminotransferase to platelet ratio index on carcinogenesis in chronic hepatitis B treated with entecavir

AIMS

We sought to compare the effects of FIB-4 index and aspartate aminotransferase to platelet ratio index (APRI) on hepatocellular carcinoma (HCC) incidence in chronic hepatitis B (CHB) patients undergoing entecavir (ETV) therapy.

PATIENT AND METHODS

A total of 338 nucleosides analogue therapy naïve CHB patients initially treated with ETV were analyzed. The optimal cutoff points in each continuous variable were determined by receiver operating curve (ROC) analysis. The effects of FIB-4 index and APRI on HCC incidence were compared using time-dependent ROC analysis and factors linked to HCC incidence were also examined using univariate and multivariate analyses.

RESULTS

There were 215 males and 123 females with the median age of 52 years and the median baseline HBV-DNA level of 6.6 log copies/ml. The median follow-up interval after the initiation of ETV therapy was 4.99 years. During the follow-up period, 33 patients (9.8%) developed HCC. The 3-, 5- 7-year cumulative HCC incidence rates in all cases were 4.4%, 9.2% and 13.5%, respectively. In the multivariate analysis, FIB-4 index revealed to be an independent predictor associated with HCC incidence, while APRI was not. In the time-dependent ROC analyses for all cases and for all subgroups analyses stratified by viral status or cirrhosis status, all area under the ROCs in each time point (2-, 3-, 4-, 5-, 6-, and 7-year) of FIB-4 index were higher than those of APRI.

CONCLUSION

FIB-4 index rather than APRI can be a useful predictor associated with HCC development for CHB patients undergoing ETV therapy.

Hepatitis B virus long-term impact of antiviral therapy nucleot(s)ide analogues (NUCs)

The goal of antiviral therapy is to improve the quality of life and survival of patients with chronic hepatitis B (CHB) by halting the progression to cirrhosis, end-stage liver disease or hepatocellular carcinoma (HCC), thus preventing anticipated liver-related death. Oral administration of potent and less resistance-prone nucleot(s)ide analogues (NUCs), such as entecavir (ETV) and tenofovir disoproxil fumarate (TDF) has become the most popular treatment strategy worldwide because of their excellent efficacy and safety profile as well as easy management confirmed in both registration trials and in clinical practice studies. Long-term administration of ETV or TDF suppresses HBV replication in >95% of patients, resulting in biochemical remission, histological improvement including the regression of cirrhosis and prevention or reversal of clinical decompensation but not the development of HCC, particularly in patients with cirrhosis. Moreover, NUCs can be administered to all patients including those with severe liver disease, the elderly and in those who do not respond, are unwilling to take or have contraindications to interferon. The need for long-term, perhaps indefinite, treatment is the main limitation of NUCs therapy with the associated costs, unknown long-term safety and the low rates of hepatitis B surface antigen (HBsAg) seroclearance, which is still the best stopping rule for NUCs-treated patients with cirrhosis.

An evaluation of entecavir for the treatment of chronic hepatitis B infection in adults

Entecavir is a nucleoside analogue of 2'-deoxyguanosine whose intracellular triphosphate form inhibits replication of the hepatitis B virus. Entecavir is recommended as a first-line monotherapy option for nucleos(t)ide-naïve patients with HBeAg-positive or -negative chronic hepatitis B infection. Entecavir has a three-step mechanism of action: It maintains viral suppression with a greater than 90% chance of undetectable hepatitis B virus DNA during continuous therapy, improves liver histology, and reduces the risk of liver failure or hepatocellular carcinoma development. The safety profile of long-term entecavir therapy is favorable; however, its optimal treatment duration is unknown. Entecavir monotherapy is not a rescue option for patients with lamivudine/adefovir resistance or baseline lamivudine-resistant mutants; rather, combination treatment is recommended for patients with lamivudine/adefovir resistance.

Lamivudine switch therapy in chronic hepatitis B patients achieving undetectable hepatitis B virus DNA after 3 years of entecavir therapy: A prospective, open-label, multicenter study

The subsequent maintenance therapy in chronic hepatitis B (CHB) patients after long-term viral replication suppression is still uncertain. We aim to evaluate the efficacy of lamivudine (LAM) maintenance therapy in CHB patients achieving undetectable hepatitis B virus (HBV) DNA after 3 years of entecavir (ETV) therapy. Consecutive CHB patients who received at least 3 years of ETV and achieved HBV DNA negativity were allocated either LAM switch therapy or stopped ETV therapy in a prospective, open-label study. Another group of sex- and age-matched patients with continuous ETV therapy for at least 4 years served as historical control group. The primary outcome measurement of the study was relapse of HBV DNA (defined as serum HBV DNA level ≥ 2000 IU/mL). A total of 74 patients, including 42 of LAM switch and 32 of the nonswitch group, were enrolled. There were no significant differences in demographics, except a higher proportion of patients with positive hepatitis B envelope antigen in the nonswitch group at the initiation of ETV therapy. The LAM switch group had significantly lower 1-year relapse rate of HBV within 1 year compared to the nonswitch group (14.3% vs. 75%, p<0.001). However, none of the 48 historical control patients developed relapse of HBV, which was significantly lower than the rate in LAM switch group (p < 0.001). LAM switch was the only factor associated with HBV DNA relapse. In conclusion, continuous long-term potent nucleot(s)ide analogue therapy is mandatory for prevention of viral relapse in CHB patients.

On-treatment and off-treatment efficacy of entecavir in a real-life cohort of chronic hepatitis B patients

BACKGROUND AND AIMS

Entecavir (ETV) is a potent nucleoside analogue with high genetic barrier to resistance. In this study, real-life clinical experiences in the long-term use of ETV and the durability of its off-treatment effectiveness were analyzed.

MATERIALS AND METHODS

This study was based on a large real-life cohort of 2240 chronic hepatitis B patients treated with ETV between January 2006 and December 2012 using a centralized electronic data repository.

RESULTS

Among 2240 patients, 804 patients were treatment naive and underwent ETV monotherapy. Their mean treatment duration was 712±493 days, with a cumulative proportion of patients achieving HBV DNA less than 300 copies/ml in 85.8, 95.7, and 97.6% at years 1, 2, and 3, respectively. Predictors for earlier virologic response were female sex, lower HBV DNA, higher alanine transaminase, lower platelet count, and HBeAg negativity at baseline. In patients who achieved virologic response and HBeAg loss, the cumulative relapse rate was 91.3% in 2 years after the cessation of treatment. During the treatment, 34 patients developed hepatocellular carcinoma, among whom 30 patients had cirrhosis before treatment initiation. ETV treatment showed efficient virologic response as the treatment duration was extended, but off-treatment efficacy was not durable, and the antiviral treatment showed some limitation in preventing hepatocellular carcinoma among liver cirrhosis patients, implying that treatment cessation should be taken into consideration more carefully.

CONCLUSION

This study from a real-life cohort may provide data on treating chronic hepatitis B patients more close to everyday clinical practice.

Continuous up to 4 Years Entecavir Treatment of HBV-Infected Adolescents - A Longitudinal Study in Real Life

This study evaluated the long-term (up to 4 years) efficacy and safety of entecavir ETV treatment and analysed the significance of baseline and on-treatment factors in long-term ETV outcomes in adolescents with chronic hepatitis B (CHB). We determined the cumulative virological and serological outcomes of 44 adolescents with CHB receiving ETV for up to 4 years. To investigate the dynamics of HBV DNA, ALT activity and hepatitis B e antigen (HBeAg) seroconversion over time and their associations with the considered factors, generalized estimating equation (GEE) models were used. The cumulative rates of undetectable HBV DNA (<20 IU/ml) and HBeAg seroconversion after 4 years were 89.7% and 55.4%, respectively. In the study group, we showed that having undetectable HBV DNA at the 6th or 12th month of therapy predicted the achievement of a sustained response rate (SRR, defined as the loss of HBV DNA, loss of HBeAg and ALT normalization) at year 3 of ETV therapy (P = 0.048, OR = 5.83; P = 0.012; OR = 14.57, respectively). The GEE analysis indicated that of the different factors, the duration of ETV therapy had a strong impact on the achievement of virological suppression, HBeAg seroconversion and SRR in adolescents. Each month after the initiation of therapy, the odds of loss of HBV DNA increased by approximately 5% (OR = 1.05, P<0.0001), on average. Additionally, the GEE analysis revealed that adolescents with an age at infection of ≥10 years had 3 times higher odds of achieving undetectable HBV DNA than patients with a younger infection age (OR = 3.67, P = 0.028). None of the ETV-treated patients reported significant adverse effects. ETV is an effective and safe treatment option for adolescents with CHB. Undetectable HBV DNA in the 6th and/or 12th month of ETV treatment and older age at infection could predict maintained virological suppression.

A predictive model for carcinogenesis in patients with chronic hepatitis B undergoing entecavir therapy and its validation

We created a model to predict the development of liver carcinogenesis in patients with chronic hepatitis B (CHB) undergoing entecavir (ETV) therapy and to validate the accuracy using an independent dataset.A total of 328 CHB subjects were analyzed. Subjects were randomly assigned into 2 groups: the training group (n = 164) and the validation group (n = 164). Using data from the training group, we built a predictive model for liver carcinogenesis by performing univariate and multivariate analyses using variables associated with liver carcinogenesis. We subsequently assessed the applicability of the constructed model in the validation group.The median (range) follow-up periods in the training and the validation groups were 5.03 years (1.03-9.98) and 4.84 years (1.10-9.97), respectively. The proportion of hepatitis B virus-DNA at 24 weeks <1.9 log IU/mL in the training group was 70.7% (116/164), while that in the validation group was 71.3% (117/164). For the entire cohort (n = 328), the median alpha-fetoprotein (AFP) value at 24 weeks (3.45 ng/mL; range, 0.9-102.7 ng/mL) significantly decreased compared to the baseline values (5.55 ng/mL; range, 0.9-1039.5 ng/mL), while the median alanine aminotransferase (ALT) value at 24 weeks (24 IU/mL; range, 6-251 IU/mL) also significantly decreased compared to baseline values (57 IU/mL; range, 7-1450 IU/mL). During the observation period, hepatocellular carcinoma (HCC) developed in 15 (9.1%) patients in the training group and in 17 (10.4%) patients in the validation group. The 3- and 5-year cumulative HCC incidence rates in the entire cohort were 4.48% and 9.52%, respectively. In the multivariate analysis of the training group, age ≥54 years (P = 0.0273), ALT level at 24 weeks (P = 0.0456), and AFP at 24 weeks (P = 0.0485) were found to be significant predictors linked to HCC. Using these independent predictors, the risk for HCC development was well stratified in the validation group (overall significance, P < 0.0001). Similar results were observed in subgroup analyses of patients with or without cirrhosis and HBe antigen positivity.In conclusion, our predictive model was well verified; hence, it may be a promising model for the prediction of the development of liver carcinogenesis in CHB patients undergoing ETV therapy.

A five years study of antiviral effect of entecavir in Chinese chronic hepatitis B patients

Entecavir (ETV) is a potent viral replication inhibitor for chronic hepatitis B (CHB) patients. To investigate the efficacy of ETV in Chinese nucleos(t)ide(NA)-experienced CHB patients. Among 89 CHB patients with ETV monotherapy for ≥6 months, 33/89 (37%) or 56/89 (73%) were NA-naïve or NA-experienced. During a median follow-up of 5.75 years, all NA-naïve CHB patients achieved VR without genotypic ETV-resistance. However, VR was observed in 50/56 (~90%) of NA-experienced CHB patients during a median follow-up of 4.75 years. Antiviral efficacy was not reduced in patients with previous lamivudine (LAM) with/without LAM-resistance (HR 0.465; 95% CI 0.196–1.100; p > 0.05) (HR 0.472; 95% CI 0.205–1.091; p > 0.05). Patients with a primary treatment failure to adefovir (ADV) had a reduced probability of achieving VR compared to NA-naïve (HR 0.496; 95% CI 0.287–0.857; p < 0.01). Previous ADV-experienced patients with a partial VR (HR 1.253; 95% CI 0.429–3.665; p > 0.05) did not influence antiviral response to ETV. The antiviral efficacy of ETV is not influenced by previous treatment LAM with/without LAM-resistance. ETV may still be an option in ADV-experienced patients with a partial VR, but not advised in patients with a primary treatment failure to ADV.

An evaluation of entecavir treatment among nucleos(t)ide-naïve Moroccan patients with chronic hepatitis B

OBJECTIVE

To analyse the efficacy and safety of entecavir (ETV) treatment in nucleos(t)ide (NUC)-naïve Moroccan patients with chronic hepatitis B.

METHODS

We retrospectively analysed 41 NUT-naïve Moroccan patients with chronic hepatitis B who received ETV 0,5 mg/day monotherapy for at least 3 months, of whom 3 were HBV envelope antigen (HbeAg) positive and 38 were HBeAg negative. The primary end point was the proportion of patients achieving virological response. Secondary end points included biochemical response (alanine transaminase (ALT) normalisation), serological response (HbeAg and HBV surface antigen (HBsAg) loss or seroconversion) and safety.

RESULTS

The median follow-up duration was 74 weeks (48-144 weeks) and mean age was 43.8 years. Of 41 patients, 6 were primary non-responders and 2 achieved partial virological response at week 48, whereas 35 achieved undetectable hepatitis B virus (HBV) DNA at month 12. Viral suppression was maintained in 97.6% of patients after 3 years of ETV treatment. One patient experienced a virological breakthrough at month 12 of treatment. ALT normalisation occurred in 100% of the patients after 1 year of treatment. Only three patients in our study were HbeAg positive, of whom one has experienced seroconversion at month 12 of treatment. However, HBsAg loss or seroconversion was not achieved during the period of the study. No serious adverse event was reported.

CONCLUSIONS

These preliminary results showed that ETV is a safe and potent inhibitor of HBV in NUC-naïve Moroccan patients, but we need to observe more patients for a longer period of time, in order to assess the long-term effectiveness, safety, resistance profile and predictive factors for virological and serological response of ETV.

Efficacy of entecavir and tenofovir in chronic hepatitis B under treatment in the public health system in southern Brazil

There are about 350 million hepatitis B virus (HBV) carriers worldwide and chronic HBV is considered a major public health problem. The objective of the present study was to assess the effectiveness of the nucleos(t)ide analogues tenofovir (TDF) and entecavir (ETV) in the treatment of chronic HBV. A cross-sectional study was carried out from March-December 2013, including all patients with chronic HBV, over 18 years of age, undergoing therapy through the public health system in southern Brazil. Only the data relating to the first treatments performed with TDF or ETV were considered. Retreatment, co-infection, transplanted or immunosuppressed patients were excluded. Six hundred and forty patients were evaluated, of which 336 (52.5%) received TDF and 165 (25.8%) ETV. The other 139 (21.7%) used various combinations of nucleos(t)ide analogues and were excluded. The negativation of viral load was observed in 87.3% and 78.8% and the negativation of hepatitis B e antigen was achieved in 79% and 72% of those treated with ETV or TDF, respectively. Negativation of hepatitis B surface antigen was not observed. There was no occurrence of adverse effects. This is a real-life study demonstrating that long-term treatment with ETV and TDF is both safe and effective.

An Observational, Multicenter, Cohort Study Evaluating the Antiviral Efficacy and Safety in Korean Patients With Chronic Hepatitis B Receiving Pegylated Interferon-alpha 2a (Pegasys): TRACES Study

Currently, limited data are available regarding the efficacy and safety of pegylated interferon alpha-2a (PEG-IFN α-2a) in Korean patients with chronic hepatitis B (CHB), in whom hepatitis B virus (HBV) genotype C is the most common type.We collected data from 439 patients (HBeAg positive, n = 349; HBeAg negative, n = 90) with CHB who were treated with PEG-IFN α-2a as a first-line therapy from 18 institutions. Treatment responses at the end of treatment (ET) and at 6 months posttreatment (PT6) were compared between the patients who were treated for 24 weeks versus 48 weeks, and adverse events (AEs) were evaluated.In HBeAg-positive patients, those who received PEG-IFN α-2a for 48 weeks showed significantly higher HBV DNA suppression (HBV DNA < 2000 IU/mL) than those who were treated for 24 weeks (48 weeks vs 24 weeks; at ET, 44.4% vs 36.7%, P = 0.035; at PT6, 35.9% vs 13.3%, P = 0.035). The HBeAg seroconversion rate at ET was 18.1% in 48-week treatment group, which is significantly higher than the 2.2% (P < 0.001) that was seen in 24-week treatment group. This finding also continued at PT6 (29.0% vs 10.0%, P < 0.001). Following 48 weeks of treatment in HBeAg-negative patients, HBV DNA suppression at ET was higher than in HBeAg-positive patients (87.8% vs 44.4%). AEs were typical of those associated with PEG-IFN α-2a.In naïve Korean HBeAg-positive CHB patients treated with PEG-IFN α-2a, higher rates of HBV DNA suppression and HBeAg seroconversion were achieved in the 48-week treatment group than in the 24-week treatment group without additional risk of AEs.

Comparison of tenofovir plus lamivudine versus tenofovir monotherapy in patients with lamivudine-resistant chronic hepatitis B

Background/Aims:

Tenofovir disoproxil fumarate (TDF) exhibits similar antiviral efficacy against treatment-naïve and lamivudine (LAM)-resistant chronic hepatitis B (CHB). However, there are few clinical reports on the antiviral effects of TDF–LAM combination therapy compared to TDF monotherapy in patients with LAM-resistant CHB.

Methods:

We investigated the antiviral efficacy of TDF monotherapy vs. TDF–LAM combination therapy in 103 patients with LAM-resistant CHB.

Results:

The study subjects were treated with TDF alone (n=40) or TDF–LAM combination therapy (n=63) for ≥6 months. The patients had previously been treated with TDF-based rescue therapy for a median of 30.0 months (range, 8–36 months). A virologic response (VR) was achieved in 99 patients (96.1%): 95.0% (38/40) of patients in the TDF monotherapy group and 96.8% (61/63) of patients in the TDF–LAM combination therapy group. The VR rates were not significantly different between the TDF monotherapy and TDF–LAM combination therapy groups (88.9 vs. 87.3% at month 12, and 94.4 vs. 93.7% at month 24, log-rank p=0.652). Univariate and multivariate analyses revealed that none of the pretreatment factors were significantly associated with VR.

Conclusions:

TDF monotherapy was as effective as TDF–LAM combination therapy for maintaining viral suppression in the vast majority of patients with LAM-resistant CHB, which suggests that TDF add-on therapy with LAM is unnecessary.

Off-treatment durability of antiviral response to nucleoside analogues in patients with chronic hepatitis B

BACKGROUND

Off-treatment durability of nucleoside analogue (NA) therapy in patients with chronic hepatitis B has not been well investigated. In this study we monitored antiviral effect of NA therapy and evaluated off-treatment durability after NA cessation in patients with chronic hepatitis B.

PATIENTS AND METHODS

A total of 94 consecutive patients (39 HBeAg-negative and 55 HBeAg-positive patients) who received NA therapy were followed up for approximately 9 years. We discontinued NA according to the following criteria; undetectable serum HBV-DNA by polymerase chain reaction (PCR) on three separate occasions at least 6 months apart in HBeAg-negative patients (APASL stopping recommendation), and seroconversion from HBeAg-positive to HBeAb-positive and undetectable serum HBV-DNA by PCR for at least 12 months in HBeAg-positive patients.

RESULTS

The cumulative rate of relapse after NA cessation was 48 % and 40 % in HBeAg-negative and -positive patients, respectively. Higher baseline serum alanine aminotransferase level was the only significant predictor for maintaining remission. No patients experienced decompensation after relapse. HBsAg loss occurred at an annual rate of 1.4 % and 0.4 % in HBeAg-negative and -positive patients, respectively. Hepatocellular carcinoma developed at an annual rate of 0.6 % in both HBeAg-negative and -positive patients.

CONCLUSIONS

Almost half of the patients did not relapse after cessation of NA therapy in both HBeAg-negative and -positive patients. Therefore, NA therapy could be discontinued with close monitoring if the APASL stopping recommendation is satisfied even in HBeAg-negative patients.

Prevalence of mutations in HBV DNA polymerase gene associated with nucleos(t)ide resistance in treatment-naive patients with Chronic Hepatitis B in Central China

Objective

There are a lot of disagreements in the studies on hepatitis B virus (HBV) DNA polymerase mutation rate associated with nucleos(t)ide analogues (NAs) in treatment-naive chronic hepatitis B (CHB) patients. This is the first study aimed to investigate the prevalence of spontaneous HBV resistance mutations in Central China.

Methods

This study included treatment-naive patients with CHB from June 2012 to May 2015 receiving care at the Institute of Liver Disease in Central China. All patients completed a questionnaire covering different aspects, such as family medical history, course of liver disease, medication history, alcohol use, among others. Mutations in HBV DNA polymerase associated with NAs resistance were detected using INNO-LiPA assay.

Results

269 patients were infected with HBV genotype B (81.4%), C (17.9%), and both B and C (0.7%). Mutations in HBV DNA polymerase were detected in 24 patients (8.9%) including rtM204I/V (n = 6), rtN236T (n = 5), rtM250V (n = 2), rtL180M (n = 2), rtT184G (n = 1), rtM207I (n = 1), rtS202I (n = 1), rtM204V/I & rtL180M (n = 5), and rtM204I & rtM250V (n = 1).

Conclusion

Spontaneous HBV resistance mutations in HBV DNA polymerase were found in treatment-naive patients with CHB in Central China. These findings suggest that we should analyze HBV DNA polymerase resistance mutation associated with NAs before giving antiviral therapy such as lamivudine (LAM), adefovir (ADV), and telbivudine (LdT).

Hepatitis B virus: new therapeutic perspectives

Current antiviral therapies have dramatically improved the long-term outcomes of patients with chronic hepatitis B virus (HBV) infection. Both interferon (IFN) and nucleos(t)ide analogue (NA) treatments have been shown to reduce the progression of liver disease in chronic hepatitis B (CHB) patients. However, persistent covalently closed circular DNA (cccDNA) can result in a viral relapse after discontinuation of antiviral treatment. On the basis of extensive research on the HBV lifecycle and virus-host interactions, several new agents focusing on viral and host targets are under development to cure HBV. New polymerase inhibitors, tenofovir alafenamide and besifovir provide effective and safer treatment for CHB patients. Agents targeting cccDNA, such as engineered site-specific nucleases and RNA interference therapeutics could eliminate cccDNA or silence cccDNA transcription. Inhibitors of HBV nucleocapsid assembly suppress capsid formation and prevent synthesis of HBV DNA. The HBV entry inhibitor, Myrcludex-B, has been shown to effectively inhibit amplification of cccDNA as well as the spread of intrahepatic infection. Agents targeting host factors that enhance innate and adaptive immune responses, including the lymphotoxin-β receptor agonist, toll-like receptor agonist, immune checkpoint inhibitors and adenovirus-based therapeutic vaccine, could play a critical role in the elimination of HBV-infected cells. With all of these promising approaches, we hope to reach the ultimate goal of a cure to HBV in the near future.

Entecavir safety and effectiveness in a national cohort of treatment-naïve chronic hepatitis B patients in the US - the ENUMERATE study

BACKGROUND

Entecavir (ETV) has been shown to be safe and efficacious in randomised controlled trials in highly selected patients with hepatitis B virus (HBV) infection.

AIM

To determine the safety and effectiveness of ETV in 'real-world' HBV patients in the United States (US).

METHODS

Treatment-naïve HBV patients ≥18 years old who received ETV for ≥12 months between 2005 and 2013 were included in a retrospective, cohort study. Rates of ALT normalisation, undetectable HBV DNA, HBeAg and HBsAg loss/seroconversion, adverse events (AE) and clinical outcomes were evaluated.

RESULTS

Of 841 patients, 658 [65% male, 83% Asian; median age 47 years] met the inclusion criteria. 36% were HBeAg+ and 9.3% cirrhotic. 89% had abnormal ALT. Baseline median HBV DNA was 5.8 log 10 IU/mL. Median duration of ETV treatment was 4 years. Rates of ALT normalisation at 1, 3 and 5 years were 37.2%, 48.7% and 56.2% in HBeAg+ and 39.6%, 46.8% and 55.6% in HBeAg- patients. HBV DNA was undetectable at 1, 3 and 5 years in 34.6%, 64.7% and 84.6% in HBeAg+ patients, and 81.9%, 90.3% and 96.2% in HBeAg patients. Five-year cumulative probability of HBeAg loss and seroconversion was 46% and 33.7% and HBsAg loss was 4.6%. ETV was discontinued due to adverse events in 1.2% of patients. Hepatic decompensation occurred in 0.8%, liver cancer in 2.7% and death in 0.6%.

CONCLUSION

Entecavir treatment was safe in a large cohort of US patients, but ALT normalisation and hepatitis B virus DNA suppression rates were lower than previously reported in clinical trials.

Evolution of entecavir-resistant hepatitis B virus during entecavir and adefovir dipivoxil combination therapy

The emergence of entecavir (ETV) resistance is rare, particularly in a longitudinal study. The aim of the present study was to characterize the evolution of ETV-resistant variants during antiviral therapy using entecavir monotherapy followed by ETV-adefovir dipivoxil (ADV) combination therapy. The study included a prospective cohort of 53 consecutive chronic hepatitis B (CHB) patients. During the 60-month period of ETV therapy, 2 patients exhibited ETV resistance and their medical records were comprehensively reviewed. A total of 25 consecutive serum samples were regularly collected from the 2 patients. All the samples were used to characterize the evolution of the polymerase gene mutations using pyrosequencing. The linkage of the variants was analyzed from 87 reverse transcriptase sequences of 3 selective samples using clone sequencing. The 2 patients presented with viral breakthrough during ETV monotherapy. In patient A, the rtL180M, rtS202G and rtM204V mutant variants were detected using pyrosequencing prior to virological breakthrough. Although the viral load declined following the administration of ADV, the ETV-resistant variants were persistently dominant in the viral populations. In patient B, the rtL180M, rtM204I and rtM204V mutants were present in ~70, 30 and 10% of the viral populations, respectively, at the time of study entry. In addition, rtT184F was present in ~20% of the viral population during virological breakthrough, at month 24. The rtL180M, rtT184F and rtM204V were predominant during the combination treatment. Clonal analysis further revealed that the rtS202G or rtT184F was in all cases co-localized with rtL180M and rtM204V in any single virus isolate clone. The results of the present study indicate that the addition of ADV therapy with ETV for treating ETV-resistant mutation may not inhibit the replication of ETV-resistant variants that developed previously in lamivudine-treated CHB patients.

Long-term effects of peginterferon alfa-2a therapy in Japanese patients with chronic hepatitis B virus infection

Background

There is no information on the long-term effects of peginterferon (PEG-IFN) alfa-2a therapy for chronic hepatitis B (CHB) in Japan. This double-blind, randomized trial investigated the efficacy of PEG-IFN therapy.

Methods

We analyzed 22 Japanese patients with CHB (hepatitis B e antigen [HBeAg]-positive: 17, HBeAg-negative: 5) treated with PEG-IFN alfa-2a and followed-up posttreatment for 5 years. Responders represented patients who showed persistent normalization of alanine transferase (ALT) levels, HBeAg clearance, and low hepatitis B virus (HBV) DNA levels (HBeAg-positive patient; <5 log copies/mL, HBeAg-negative patient; <4.3 log copies/mL) at end of treatment, and at 1, 2, 3, 4 and 5 years posttreatment. In addition, baseline HBeAg-positive patients who showed sustained normalization of ALT level, HBeAg clearance, and low HBV DNA level for more than 6 months until at 1, 2, 3, 4, and 5 years after completion of PEG-IFN were also classified as “triple responders” and the proportion of triple responders relative to all patients was termed the “triple response rate”.

Results

The response rates among HBeAg-positive patients were 13 %, 25 %, 14 %, 21 % and 21 % at end of treatment, and at 1, 2, 3, 4, and 5 years, respectively. The response rate tended to be higher in patients treated for 48 than 24 weeks. The respective response rates among HBeAg-negative patients were 0 %, 20 %, 20 %, 20 % and 25 %. During the treatment period, hepatitis B surface antigen (HBsAg) clearance at 3.5 years was noted in one patient, who was 37-year-old, male, had genotype C and received PEG-IFN alfa-2a at 90 μg for 48 weeks.

Conclusion

At 5 years after completion of PEG-IFN, the triple response rate in HBeAg-positive patients and combined response rate in HBeAg-negative patients were 21 % (3/14) and 25 % (1/4), respectively. The triple response was seen in three patients who had all been treated with PEG-IFN for 48 weeks.

Recent Advances in the Management of Chronic Hepatitis B Including Suppression of Hepatocellular Carcinoma by Entecavir and Interferon

At present, for adults with chronic hepatitis B virus (HBV) infection, two new analogues, entecavir (ETV) and tenofovir, are recommended as the first-line therapy by the EASL (European Association for the Study of the Liver), AASLD (American Association for the Study of Liver Diseases), and APASL (Asian Pacific Association for the Study of the Liver) guidelines. The use of pegylated interferon-α (PEG IFN-α) is recommended as the first-line therapy instead of standard IFN-α according to the above 3 guidelines. In this paper, the aim was to assess: (1) the long-term efficacy and safety as well as the resistance to ETV and tenofovir disoproxil fumarate (TDF); (2) the efficacy of PEG IFN-α; (3) the role of combination therapy with IFN plus two analogues, such as lamivudine and ETV; (4) the efficacy and safety of two analogues with cirrhosis, and (5) suppression of hepatocellular carcinoma (HCC) by ETV and IFN treatment. The results are as follows: (1) both ETV and TDF showed long-term efficacy and safety; (2) PEG IFN-α resulted in a greater decline in HBV DNA levels and a higher rate of HBeAg seroconversion; (3) combination therapy with IFN plus two analogues did not elevate the rate of sustained responses; (4) both ETV and TDF showed efficacy and safety with cirrhosis (ETV especially displayed efficacy and safety with decompensated cirrhosis), and (5) suppression of HCC was observed by ETV and IFN.

Logistic regression analysis of factors influencing virological response to nucleos(t)ide analog therapy in previously untreated chronic hepatitis B patients

AIM: To investigate the factors influencing virological response to nucleoside analog therapy in previously untreated chronic hepatitis B patients.

METHODS: Two hundred and twelve previously untreated patients with chronic hepatitis B who received nucleos(t)ide analogue monotherapy were enrolled in this study. According to HBV DNA load after 24 wk of treatment, the patients were divided into three groups: patients with complete virological response, those with partial virologic response, and those with primary treatment failure. Logistic regression method was used to analyze the relationship between baseline indicators and virological response.

RESULTS: The choice of nucleos(t)ide analogue (P = 0.008) and sex (P = 0.023) were factors affecting primary treatment failure; ADV was associated a higher rate of primary treatment failure than other three antiviral drugs, and male gender was also associated a higher rate of primary treatment failure. HBeAg status (P = 0.028) and AST/ALT ratio (P = 0.018) were factors affecting partial virological response. HBeAg positivity and higher AST/ALT ratio were associated with a higher rate of partial virological response.

CONCLUSION: The choice of ADV and male gender are associated with a higher rate of primary treatment failure. HBeAg positivity and higher AST/ALT ratio are associated with a higher rate of partial virological response.

A model with combined viral and metabolic factors effectively predicts HBeAg status under long term entecavir therapy: a prospective cohort study

Background & Aim

The aim was to extract factors from virologic and biochemical profiles at baseline and 24 weeks of treatment to predict HBeAg seroconversion in patients treated with ETV.

Methods

HBeAg positive chronic hepatitis B patients receiving ETV naïve-treatment were enrolled. HBV DNA, ALT, and serological markers were prospectively monitored every 6 months for 240 weeks. The cumulative rates of virologic response (VR), biochemical response (BR), and HBeAg seroconversion were determined, and potential predictors for HBeAg seroconversion were identified through uni/multivariate analysis.

Result

Two hundred twenty nine patients were eligible for this study. The cumulative rates of VR, BR, and HBeAg seroconversion at 240 weeks were 88.4 %, 100 %, and 36.7 %, respectively. Multivariate analysis showed that HBV DNA (OR, 2.8, p = 0.003), ALT (OR, 2.6, p = 0.005) at baseline, undetectable HBV DNA within 24 weeks (OR = 3.2, p < 0.001), and body mass index (BMI) ≥24kg/m² (OR = 0.038, p = 0.013) were associated with HBeAg seroconversion. A prediction model for probability of HBeAg seroconversion was constructed. Patients can be classified into high (>40 %), intermediate (20–40 %), or low (≤20 %) groups based on the calculated probability of HBeAg seroconversion. The cumulative rates of HBeAg seroconversion were different among the three groups (p < 0.001). About 58 % patients in the high probability group achieved HBeAg seroconversion while almost 90 % patients within the low group remained HBeAg positive.

Conclusion

A combination of HBV DNA, ALT and BMI values at baseline, and undetectable HBV DNA level within 24 weeks can predict HBeAg seroconversion. Both viral and metabolic factors likely determine HBeAg status with ETV treatment.

Trial registration

CTR20132358

A Treatment Algorithm for the Management of Chronic Hepatitis B Virus Infection in the United States: 2015 Update

Chronic hepatitis B (CHB) continues to be an important public health problem worldwide, including in the United States. An algorithm for managing CHB was developed by a panel of United States hepatologists in 2004 and subsequently updated in 2006 and 2008. Since 2008, additional data on long-term safety and efficacy of licensed therapies have become available and have better defined therapeutic options for CHB. The evidence indicates that potent antiviral therapy can lead to regression of extensive fibrosis or even cirrhosis, thus potentially altering the natural history of CHB. In addition, appropriate choice of antiviral agent can minimize the risk of resistance. This updated algorithm for managing CHB is based primarily on evidence from the scientific literature. Where data were lacking, the panel relied on clinical experience and consensus expert opinion. The primary aim of antiviral therapy for CHB is durable suppression of serum hepatitis B virus (HBV) DNA to low or undetectable levels. CHB patients who have HBV DNA >2000 IU/mL, elevated alanine aminotransferase level, and any degree of fibrosis should receive antiviral therapy regardless of their hepatitis B e antigen status. CHB patients with HBV DNA >2000 IU/mL and elevated alanine aminotransferase level but no evidence of fibrosis may also be considered for antiviral therapy. Approved antiviral therapies for CHB are interferon alfa-2b, peginterferon alfa-2a, lamivudine, adefovir, entecavir, telbivudine, and tenofovir, although the preferred first-line treatment choices are peginterferon alfa-2a, entecavir, and tenofovir. In determining choice of therapy, considerations include efficacy, safety, rate of resistance, method of administration, duration, and cost.

Effect of tenofovir disoproxil fumarate on drug-resistant HBV clones

BACKGROUND & AIMS

Tenofovir disoproxil fumarate (TDF) has been approved for chronic hepatitis B treatment, and favorable susceptibility of hepatitis B virus (HBV) has been indicated. However, differences in TDF susceptibility among HBV genotypes and drug-resistant strains are unclear. In this study, TDF susceptibilities between genotypes A and C were evaluated in vitro and in vivo using several drug-resistant HBV clones.

METHODS

HBV expression plasmids were constructed from sera of HBV carriers, and drug-resistant substitutions were introduced by site-directed mutagenesis. TDF susceptibility was evaluated by changes of core-associated HBV replication intermediates in vitro or by change of serum HBV DNA in human hepatocyte chimeric mice carrying each HBV clone in vivo.

RESULTS

TDF susceptibilities of lamivudine-resistant clones (rtL180M/M204V) and lamivudine plus entecavir-resistant clones (rtL180M/S202G/M204V) were similar to wild type clones in vitro. However, lamivudine plus adefovir-resistant clones (rtA181T/N236T) acquired tolerance to TDF, and the rtN236T mutation was considered to be a causal substitution for TDF resistance. Furthermore, genotypic differences in TDF susceptibility were also observed between genotypes A and C in vitro, and the differences could be confirmed in vivo (p = 0.023).

CONCLUSIONS

The present study indicates that TDF susceptibility varies among HBV genotypes and drug-resistant HBV clones.

Tenofovir-based rescue therapy for chronic hepatitis B patients who had failed treatment with lamivudine, adefovir, and entecavir

BACKGROUND AND AIM

In the past decade, many chronic hepatitis B (CHB) patients have undergone sequential treatment with lamivudine (LAM), adefovir (ADV), and entecavir (ETV) to manage antiviral resistance or insufficient suppression of HBV-DNA. Very limited data are available on the efficacy of tenofovir (TDF) rescue regimens in patients with multidrug resistance (MDR).

METHODS

We investigated the antiviral efficacy of TDF/LAM combination therapy versus TDF/ETV combination therapy in 52 patients who failed three previous antiviral therapies.

RESULTS

The study subjects were treated with TDF/LAM combination therapy (n = 25) or TDF/ETV combination therapy (n = 27) for more than six months. Virologic response (VR) occurred in 39 (75%) patients (19 patients belonged to the TDF/LAM group and 20 patients belonged to the TDF/ETV group). The VR rates were not different between the TDF/LAM and TDF/ETV groups (56.0% vs 51.9% at month 12, and 72.0% vs 78.8% at month 18; log rank P = 0.515). In addition, treatment efficacy of TDF/LAM combination or TDF/ETV combination was not statistically different according to types of MDR. In multivariate analysis, absolute HBV-DNA level at the start of TDF rescue treatment (P < 0.001; OR, 0.452; 95% CI, 0.306-0.666) was only significantly associated with VR.

CONCLUSIONS

TDF/ETV combination therapy was not associated with higher rate of VR compared with TDF/LAM combination therapy in MDR CHB patients. These results raise the suspicion about the superiority of the combination therapy over TDF monotherapy. The lower HBV-DNA levels at the start of TDF-based rescue therapy were associated with higher VR.

Efficacy and safety of tenofovir in nucleos(t)ide-naïve patients with genotype C chronic hepatitis B in real-life practice

BACKGROUND

Tenofovir disoproxil fumarate (TDF) has demonstrated potent antiviral activity against hepatitis B virus (HBV) in clinical trials. Although its efficacy has been demonstrated in Caucasian populations, TDF has not previously been studied in Korean patients who present the predominance of HBV genotype C and of vertical or perinatal transmission.

OBJECTIVE

The aim of this study was to evaluate the efficacy of TDF in Korean chronic hepatitis B (CHB) patients in real-life practice, and to determine the clinical variables that contribute to virologic response.

SETTING

Large academic medical center in Korea.

METHOD

We retrospectively investigated the efficacy of TDF treatment for more than 6 months in 151 nucleos(t)ide-naïve CHB patients.

MAIN OUTCOME MEASURE

The primary endpoint was a virologic response (VR), defined as an HBV DNA level of <12 IU/mL. Secondary endpoints were rates of alanine aminotransaminase (ALT) normalization, hepatitis B e antigen (HBeAg) seroconversion, virologic breakthrough, and safety.

RESULTS

All patients were the genotype C2. The median duration of TDF treatment was 13 months (range 7-18 months). Ninety-two (61.0 %) patients were HBeAg positive. The mean pre-treatment HBV DNA level was 6.34 ± 1.42 log10 IU/mL. Among the 131 patients with elevated ALT levels at baseline, 128 (97.7 %) patients achieved ALT normalization during TDF treatment. VR was achieved in 97 (64.2 %) patients. The cumulative rates of VR at 6, 9, 12, and 18 months were 47.0, 59.4, 67.9, and 69.3 %, respectively. Among the 92 HBeAg-positive patients, 14 (15.2 %) patients achieved HBeAg seroconversion. In multivariate analysis, absolute HBV DNA levels at baseline (P < 0.001; OR 0.529; 95 % CI 0.560-0.744) and HBeAg positivity (P = 0.015; OR 0.731; 95 % CI 0.615-0.869) were significantly associated with VR. Virologic breakthrough was observed in four patients. These four patients had poor adherence to TDF. Most of the adverse events were mild in severity. No significant changes were observed in serum creatinine and phosphorus levels.

CONCLUSIONS

TDF was effective and well tolerated in Korean genotype C CHB patients in real life practice, consistent with larger registration trials. The absolute HBV DNA levels at baseline and HBeAg positivity were significantly associated with VR.

Effects of long-term entecavir treatment on the incidence of hepatocellular carcinoma in chronic hepatitis B patients

BACKGROUND AND AIM

Entecavir is one of the most-used nucleoside analogues for the treatment of patients with chronic hepatitis B virus (HBV) infection. The aim of this study was to clarify the effects of long-term entecavir treatment on the incidence of hepatocellular carcinoma (HCC).

METHODS

The participants were 249 patients with chronic HBV infection who had been treated by entecavir for more than 2 years. Hepatic functional reserve and incidence of HCC were evaluated, and the factors that might contribute to the development of HCC were analyzed.

RESULTS

Prothrombin activity was significantly elevated at 60 months after starting entecavir (from 85.9 ± 17.4 to 97.0 ± 16.9%, p < 0.001). The albumin level was also significantly elevated at 60 months after starting entecavir (from 4.0 ± 0.5 to 4.3 ± 0.3 mg/dL, p < 0.001). The annual incidence of HCC decreased over time, and the incidence of HCC was only 1.8% at 5 years after starting entecavir. On multivariate analysis for HCC incidence, older age and low platelet count were significant, independent contributing factors.

CONCLUSIONS

Long-term treatment with entecavir improved hepatic functional reserve and decreased the incidence of HCC over time after 3 years. To decrease the incidence of HCC, careful induction of long-term entecavir treatment in younger patients with chronic HBV infection and better hepatic functional reserve would be important.

Impact of alpha-fetoprotein on hepatocellular carcinoma development during entecavir treatment of chronic hepatitis B virus infection

BACKGROUND

Entecavir (ETV) is one of the first-line nucleoside analogs for treating patients with chronic hepatitis B virus (HBV) infection. However, the hepatocellular carcinoma (HCC) risk for ETV-treated patients remains unclear.

METHODS

A total of 496 Japanese patients with chronic HBV infection undergoing ETV treatment were enrolled in this study. The baseline characteristics were as follows: age 52.6 ± 12.0 years, males 58%, positive for hepatitis B e antigen 45 %, cirrhosis 19%, and median HBV DNA level 6.9 log copies (LC) per milliliter. The mean treatment duration was 49.9 ± 17.5 months.

RESULTS

The proportions of HBV DNA negativity (below 2.6 LC/mL) were 68% at 24 weeks and 86% at 1 year, and the rates of alanine aminotransferase (ALT) level normalization were 62 and 72%, respectively. The mean serum alpha-fetoprotein (AFP) levels decreased significantly at 24 weeks after ETV treatment initiation (from 29.0 ± 137.1 to 5.7 ± 27.9 ng/mL, p < 0.001). The cumulative incidence of HCC at 3, 5, and 7 years was 6.0, 9.6, and 17.2%, respectively, among all enrolled patients. In a multivariate analysis, advanced age [55 years or older, hazard ratio (HR) 2.84; p = 0.018], cirrhosis (HR 5.59, p < 0.001), and a higher AFP level (10 ng/mL or greater) at 24 weeks (HR 2.38, p = 0.034) were independent risk factors for HCC incidence. HCC incidence was not affected by HBV DNA negativity or by ALT level normalization at 24 weeks.

CONCLUSIONS

The AFP level at 24 weeks after ETV treatment initiation can be the on-treatment predictive factor for HCC incidence among patients with chronic HBV infection.

Impact of prior lamivudine use on the antiviral efficacy and development of resistance to entecavir in chronic hepatitis B patients

Background/Aims

To determine the efficacies of entecavir (ETV) in nucleos(t)ide analogue (NA)-naïve chronic hepatitis B (CHB) patients and in those with prior lamivudine (LAM) use who did not develop resistance.

Methods

We retrospectively enrolled 337 patients with CHB who were treated with ETV (0.5 mg daily) for at least 30 months. The study included 270 (80.1%) NA-naïve patients and 67 (19.9%) LAM-use patients. Ten of the LAM-use patients were refractory to LAM therapy without developing resistance.

Results

Genotypic resistance to ETV developed more frequently in the LAM-use group (13.1%) than in the NA-naïve group (2.6%) at 60 months (P=0.009). In subgroup analysis, after excluding the 10 patients who were refractory to LAM therapy, the cumulative probability of ETV resistance did not differ significantly between the two groups (P=0.149). Prior LAM refractoriness and a higher hepatitis B virus DNA level at month 12 were independent predictive factors for the development of ETV resistance.

Conclusions

ETV resistance developed more frequently in LAM-use patients with CHB. However, prior LAM use without refractoriness did not affect the development of ETV resistance. The serum hepatitis B virus DNA level at month 12 was a major predictor for the development of ETV resistance.

Deep sequencing analysis of HBV genotype shift and correlation with antiviral efficiency during adefovir dipivoxil therapy

BACKGROUND

Viral genotype shift in chronic hepatitis B (CHB) patients during antiviral therapy has been reported, but the underlying mechanism remains elusive.

METHODS

38 CHB patients treated with ADV for one year were selected for studying genotype shift by both deep sequencing and Sanger sequencing method.

RESULTS

Sanger sequencing method found that 7.9% patients showed mixed genotype before ADV therapy. In contrast, all 38 patients showed mixed genotype before ADV treatment by deep sequencing. 95.5% mixed genotype rate was also obtained from additional 200 treatment-naïve CHB patients. Of the 13 patients with genotype shift, the fraction of the minor genotype in 5 patients (38%) increased gradually during the course of ADV treatment. Furthermore, responses to ADV and HBeAg seroconversion were associated with the high rate of genotype shift, suggesting drug and immune pressure may be key factors to induce genotype shift. Interestingly, patients with genotype C had a significantly higher rate of genotype shift than genotype B. In genotype shift group, ADV treatment induced a marked enhancement of genotype B ratio accompanied by a reduction of genotype C ratio, suggesting genotype C may be more sensitive to ADV than genotype B. Moreover, patients with dominant genotype C may have a better therapeutic effect. Finally, genotype shifts was correlated with clinical improvement in terms of ALT.

CONCLUSIONS

Our findings provided a rational explanation for genotype shift among ADV-treated CHB patients. The genotype and genotype shift might be associated with antiviral efficiency.

Prolonged entecavir therapy is not effective for HBeAg seroconversion in treatment-naive chronic hepatitis B patients with a partial virological response

The aims of this study were to investigate the efficacy of prolonged entecavir (ETV) therapy in treatment-naive chronic hepatitis B (CHB) patients and to determine whether continuous ETV therapy is feasible to achieve HBeAg seroconversion, particularly in patients with partial virological response (PVR). A total of 142 treatment-naive patients with CHB were enrolled. The mean duration of treatment was 65 (range, 26 to 90) months, and 86 patients (60.6%) were HBeAg positive. PVR was defined as detectable hepatitis B virus (HBV) DNA (>116 copies/ml) at year 1. The cumulative incidence of virological response (VR) increased from 54.9% at year 1 to 98.2% at year 7. HBeAg positivity (odds ratio [OR], 4.146; P = 0.001) and initial alanine aminotransferase (ALT) (OR, 0.997; P = 0.004) were independent risk factors for PVR. Among the 64 patients with PVR, 47 patients (73.4%) achieved VR within 4 years after prolonged ETV therapy without treatment adaptation. Three patients (2.1%) experienced virological breakthrough and HBV variants with genotypic resistance. The cumulative rate of HBeAg seroconversion was significantly higher in the patients with VR than in the patients with PVR (P = 0.018). None of the PVR patients with HBV DNA at ≥5,000 copies/ml at year 1 ever experienced HBeAg seroconversion. Multivariate analysis identified VR at year 1 as the only determinant of HBeAg seroconversion (hazard ratio [HR], 3.009; P = 0.010). In conclusion, although there were patients with PVR, prolonged ETV therapy showed excellent VR, with only 2.1% emergence of viral resistance during a 7-year follow-up. However, to achieve HBeAg seroconversion, drug modification is needed for HBeAg-positive patients with PVR (especially those with HBV DNA at ≥5,000 copies/ml at year 1).

Current and future directions for treating hepatitis B virus infection

Hepatitis B virus (HBV) persistently infects approximately 350 million people, and approximately 600000 liver-related deaths are observed per year worldwide. HBV infection is also one of the major risk factors for hepatocellular carcinoma (HCC). The persistence of serum hepatitis B e antigen (HBeAg) and high level of serum HBV DNA are thought to reflect a high HBV replication status in hepatocytes, causing cirrhosis, HCC and liver-related deaths. It has been reported that antiviral therapy, such as peginterferon and nucleos(t)ide analogues (NUCs), could suppress liver-related death by inhibiting the HBV DNA levels and inducing seroconversion from HBeAg to antibody to HBe antigen. Currently, peginterferon is widely used, but there are also several disadvantages in the use of peginterferon, such as various adverse events, the administration route and duration. It is difficult to predict the effects of treatment and interferon is contraindicated for the patients with advanced fibrosis of the liver and cirrhosis. With respect to NUCs, entecavir and tenofovir disoproxil fumarate are current the first-choice drugs. NUCs can be administered orally, and their anti-viral effects are stronger than that of peginterferon. However, because cessation of NUC administration leads to high levels of viral replication and causes severe hepatitis, they must be administered for a long time. On the other hand, the use of both interferon and NUCs cannot eliminate covalently closed circular DNA of HBV. In this review, we evaluate the natural course of chronic HBV infection and then provide an outline of these representative drugs, such as peginterferon, entecavir and tenofovir disoproxil fumarate.

Control of oxidative stress in hepatocellular carcinoma: Helpful or harmful?

Oxidative stress is becoming recognized as a key factor in the progression of chronic liver disease (CLD) and hepatocarcinogenesis. The metabolically important liver is a major reservoir of mitochondria that serve as sources of reactive oxygen species, which are apparently responsible for the initiation of necroinflammation. As a result, CLD could be a major inducer of oxidative stress. Chronic hepatitis C is a powerful generator of oxidative stress, causing a high rate of hepatocarcinogenesis among patients with cirrhosis. Non-alcoholic steatohepatitis is also associated with oxidative stress although its hepatocarcinogenic potential is lower than that of chronic hepatitis C. Analyses of serum markers and histological findings have shown that hepatocellular carcinoma correlates with oxidative stress and experimental data indicate that oxidative stress increases the likelihood of developing hepatocarcinogenesis. However, the results of antioxidant therapy have not been favorable. Physiological oxidative stress is a necessary biological response, and thus adequate control of oxidative stress and a balance between oxidative and anti-oxidative responses is important. Several agents including metformin and L-carnitine can reportedly control mechanistic oxidative stress. This study reviews the importance of oxidative stress in hepatocarcinogenesis and of control strategies for the optimal survival of patients with CLD and hepatocellular carcinoma.

Efficacy of Tenofovir-based Rescue Therapy in Lamivudine-resistant Chronic Hepatitis B Patients With Failure of Lamivudine and Adefovir Combination

PURPOSE

In chronic hepatitis B patients, lamivudine (LAM) and adefovir (ADV) combination therapy is commonly used as a rescue therapy for LAM resistance, but it often results in incomplete viral suppression. We investigated the antiviral efficacy of tenofovir (TDF)/LAM combination therapy versus TDF monotherapy in LAM-resistant chronic hepatitis B (CHB) patients who failed to respond to LAM plus ADV rescue therapy.

METHODS

Among 108 patients with LAM-resistant CHB who had a partial virologic response (VR) to LAM and ADV combination therapy, Eighty one patients were finally included in this study.

FINDINGS

Resistance to ADV (ADV-R) was present in 32 patients (39.5%), and the remaining 49 patients (60.5%) had a partial virologic response to LAM/ADV combination (ADV-P). The study subjects were treated with TDF alone (n=15) or TDF/LAM combination (n=66). VR was achieved in 61 patients (75.3%). The rates of VR at 6 and 12 months were not significantly different between TDF monotherapy and TDF/LAM combination therapy groups (46.7 vs. 68.2% at 6 months, and 66.7 vs. 75.9% at 12 months, log-rank P=0.357). Treatment efficacy of TDF alone or TDF/LAM combination was not statistically different according to pre-existing ADV or LAM resistant strains. In multivariate analysis, absolute HBV DNA levels at the start of TDF rescue treatment (P<0.001; OR, 0.556; 95% CI, 0.422-0.731) were the only significantly associated with VR.

IMPLICATIONS

TDF monotherapy was as effective as TDF/LAM combination therapy in maintaining viral suppression in patients with LAM-resistant patients who failed to respond to LAM/ADV combination therapy.

Antiviral therapies and prospects for a cure of chronic hepatitis B

Current therapies of chronic hepatitis B (CHB) remain limited to either pegylated interferon-α (Peg-IFN-α), or one of the five approved nucleoside analog (NA) treatments. Although viral suppression can be achieved in the majority of patients with high-barrier-to-resistance new-generation NAs (i.e., entecavir and tenofovir), HBsAg loss is achieved in only 10% of patients with both classes of drugs after a follow-up of 5 years. Attempts to improve the response by administering two different NAs or a combination of NA and Peg-IFN-α have been unsuccessful. Therefore, there is a renewed interest to investigate a number of steps in the hepatitis B virus (HBV) replication cycle and specific virus-host cell interactions as potential targets for new antivirals. Novel targets and compounds could readily be evaluated using both relevant in vitro and newly developed in vivo models of HBV infection. The addition of one or several new drugs to current regimens should offer the prospect of markedly improving the response to therapy, thus reducing the burden of drug resistance, as well as the incidence of cirrhosis and hepatocellular carcinoma (HCC).

Efficacy of prolonged entecavir monotherapy in treatment-naïve chronic hepatitis B patients exhibiting a partial virologic response to entecavir

Background/Aims

The optimal management of patients exhibiting a partial virologic response (PVR) to entecavir (ETV) has not been determined. The aim of this study was to determine the long-term efficacy of prolonged ETV monotherapy in treatment-naïve chronic hepatitis B (CHB) patients exhibiting a PVR to ETV therapy.

Methods

This study included 364 treatment-naïve CHB patients treated with ETV for ≥48 weeks and who received continuous ETV monotherapy for ≥96 weeks. PVR was defined as a decrease in serum hepatitis B virus (HBV) DNA of more than 2 log₁₀ IU/mL from baseline but with detectable HBV DNA by real-time PCR assay at week 48.

Results

Fifty-two of the 364 patients (14.3%) showed a PVR. Among them, 41 patients received continuous ETV monotherapy for ≥96 weeks (median duration 144 weeks, range 96-312 weeks), and 40 of these patients (95%) achieved a virologic response (VR, HBV DNA <20 IU/mL) during prolonged ETV monotherapy (median duration 78 weeks, range 60-288 weeks). The cumulative probabilities of a VR at weeks 96, 144, and 192 from treatment initiation were 78.0%, 92.7%, and 95.1%, respectively. The VR rate was 97.2% (35/36) in HBeAg-positive patients and 100% (5/5) in HBeAg-negative patients. In multivariate analysis, HBeAg positivity (odds ratio [OR], 9.231; 95% confidence interval [CI], 1.03-82.91; P=0.047) and a high baseline HBV DNA level (OR, 0.170; 95% CI, 0.08-0.37; P=0.000) were independently associated with a delayed virologic response. No patient developed genotypic resistance to ETV during follow-up.

Conclusions

Long-term ETV monotherapy is effective for achieving a VR in treatment-naïve CHB patients exhibiting a PVR to ETV. HBeAg positivity and high baseline HBV DNA level were independently associated with a delayed virologic response.

Improving clinical outcomes of chronic hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a global health problem, leading to cirrhosis, hepatocellular carcinoma (HCC) and liver-related deaths. Universal hepatitis B vaccination is the most cost-effective way to eradicate HBV infection with the remarkable reduction of chronic carriage, neonatal fulminant hepatitis and childhood HCC. The introduction of highly effective antiviral agents, including lamivudine, adefovir dipivoxil, entecavir, telbivudine, tenofovir disoproxil fumarate and pegylated interferons further improve short-, medium- and long-term outcomes of chronic HBV infection, such as ALT normalization, HBV DNA suppression, HBeAg seroconversion, HBsAg seroclearance, fibrosis regression, reduction of cirrhosis, HCC, liver-related deaths and the need for liver transplantation. Above all, sustained and profound viral suppression is the key to improve the clinical outcomes of chronic hepatitis B.

Optimal therapy of chronic hepatitis B: how do I treat my HBeAg-negative patients?

HBeAg negative chronic hepatitis B (CHB) is a frequent, progressive and difficult-to-cure phase of CHB. The end-point of therapy is to persistently suppress viral replication to halt progression of liver disease. Two different treatment strategies are currently available: a short-term course of pegylated interferon alpha (PEG-IFN) or long-term therapy with nucleot(s)ide analogues (NA), i.e. entecavir or tenofovir. Young patients with mild-to-moderate stages of liver disease can benefit from a 48-week course of PEG-IFN, while NA may be preferred in patients with more severe liver disease, in older patients, and in those who do not respond, are unwilling or have contraindications to PEG-IFN. Nucleot(s)ide analogues provide persistent viral suppression and biochemical normalization in almost all patients, together with the regression of fibrosis and the prevention of decompensation, but the effect on hepatocellular carcinoma rates is limited. Thus, NAs have become the most popular treatment strategy worldwide but lifelong administration is associated with high cost, unknown safety and adherence issues and an unknown risk of drug-resistance over time as well as limited rates of HBsAg seroclearance. On the other hand, PEG-IFN treatment may achieve a SVR in nearly a quarter of patients ultimately leading to HBsAg loss in almost 30-50%. Interestingly, response rates to PEG-IFN may further increase with more careful patient selection based on age, ALT and HBV DNA levels at baseline and by applying early on-treatment stopping rules based on HBV DNA and HBsAg kinetics. The combination of NA and PEG-IFN is not currently recommended but numerous studies are ongoing.

Long-term entecavir therapy results in falls in serum hepatitis B surface antigen levels and seroclearance in nucleos(t)ide-naïve chronic hepatitis B patients

Entecavir (ETV) is reported to result in suppression of hepatitis B virus DNA (HBV DNA) replication with minimal drug resistance. However, information on the long-term effect of such therapy on serum hepatitis B surface antigen (HBsAg) level and elimination of HBsAg is not available. ETV therapy was started in 553 nucleos(t)ide-naïve patients with chronic hepatitis B infection (HBeAg positive: 45%) in our hospital. Serum HBsAg levels were measured serially by the Architect assay. The median baseline HBsAg was 2180 IU/mL (0.12-243 000 IU/mL), and median follow-up period was 3.0 years, with 529, 475, 355, 247 and 163 patients followed-up for 1, 2, 3, 4 and 5 years, respectively. At year 5, the mean log HBsAg decline from baseline was -0.48 log IU/mL, and the cumulative HBsAg clearance rate was 3.5%. Multivariate analysis identified HBV DNA level at baseline (<3.0 log copies IU/mL, odd ratio = 10.2; 95% confidence interval = 1.87-55.5, P = 0.007) and HBsAg level (<500 IU/mL, odd ratio = 29.4; 95% confidence interval = 2.80-333, P = 0.005) as independent predictors of HBsAg seroclearance. These results indicate that although serum HBsAg level declines gradually during ETV therapy, HBsAg seroclearance remains a rare event.

Real-life practice of antiviral therapy and disease patterns of patients with chronic hepatitis B: a single-center retrospective observation study

PURPOSE

To analyze the spectrum of diseases in patients with chronic hepatitis B virus (HBV) infection and their association with patient clinicopathologic characteristics and the effect of antiviral therapy on the spectrum of diseases in the study cohort.

METHODS

We retrospectively reviewed the clinicopathologic and virologic records of patients with chronic HBV infection hospitalized at our institution during 2011. Demographic data, hepatitis B e antigen (HBeAg) status and HBV DNA (log10 IU/ml) were obtained.

RESULTS

A total of 1,619 patients were included; 272 (17.2 %) patients received antiviral therapy for a mean duration of 24.5 ± 18.3 months, and 71.0 % (198/279) patients were compliant with their antiviral therapy. HBeAg-positive patients had a markedly higher rate of moderate and severe CHB than HBeAg-negative patients (p < 0.001) but a significantly lower rate of liver cirrhosis (p < 0.001). The rate of severe and fulminant CHB was significantly lower in patients receiving antiviral therapy than in those not receiving antiviral therapy.

CONCLUSIONS

Patients receiving antiviral therapy exhibit a different spectrum of diseases from patients not receiving such therapy.

Entecavir combined with furin inhibitor simultaneously reduces hepatitis B virus replication and e antigen secretion

BACKGROUND

The antiviral therapy of chronic hepatitis B virus (HBV) infection pursues the dual goals, virological response (undetectable serum HBV DNA) and hepatitis B e antigen (HBeAg) serological response (serum HBeAg loss/seroconversion). It is relatively difficult, however, to realize the serological response, especially for nucleotide/nucleoside analogs. Furin, a proprotein convertase, is involved in HBeAg maturation. The suppression of furin using inhibitors accordingly reduces HBeAg secretion, but possibly enhances HBV replication. For these reasons, the strategy based on the combination of nucleoside analog entecavir (ETV) and furin inhibitors to inhibit HBV replication and HBeAg secretion simultaneously were studied here.

METHODS

The suppression of furin was performed using inhibitors decanoyl-RVKR-chloromethylketone (CMK) and hexa-D-arginine (D6R) or the expression of furin inhibitory prosegment. The influence of furin suppression on HBV replication and the effect of CMK combined with nucleoside analog entecavir (ETV) on HBV replication and HBeAg secretion was investigated in HepG2.2.15 cells. HBeAg level in media was detected using enzyme-linked immunosorbent assay. Intracellular viral antigens and HBV DNA were detected using Western and Southern blotting analyses, respectively.

RESULTS

CMK, D6R and the expression of inhibitory prosegment all significantly reduced HBeAg secretion, but only CMK enhance HBV replication. Concordantly, only CMK post-transcriptionally accumulated cytosolic HBV replication-essential hepatitis B core antigen (HBcAg). The HBcAg-accumulating effect of CMK was further found to be resulted from its redundant inhibitory effect on the trypsin-like activity of cellular proteasomes that are responsible for HBcAg degradation. Moreover, the viral replication-enhancing effect of CMK was abrogated by ETV and ETV combined with CMK reduced HBV replication and HBeAg secretion simultaneously.

CONCLUSION

The suppression of furin itself does not enhance HBV replication. Nucleotide/nucleoside analogs combined with furin inhibitors may be a potential easy way to realize the dual goals of the antiviral therapy for chronic hepatitis B in the future.

Effect of hepatitis B virus reverse transcriptase variations on entecavir treatment response

BACKGROUND

Entecavir therapy often reduces hepatitis B virus (HBV) DNA to an undetectable level, but HBV DNA remain detectable in some patients. We investigated whether baseline HBV reverse transcriptase (rt) polymorphism and quasispecies complexity and diversity were associated with treatment response.

METHODS

Pretreatment HBV DNA levels, HBV rt sequence, serology, and quasispecies complexity and diversity from 305 entecavir-treated patients were determined. These data were tested for their association with year 1 virological outcome, defined by optimal response (undetectable HBV DNA; lower limit of detection, ≤12 IU/mL) or partial response (detectable HBV DNA).

RESULTS

Four rt variants were more frequently detected in the 64 partial responders than in the 241 optimal responders (all P < .05). Multivariate analysis revealed that high baseline HBV DNA level (P < .0001; odds ratio [OR], 2.32), HBV e antigen (HBeAg) positivity (P < .001; OR, 3.70), and rt124N (P = .002; OR, 3.06) were associated with a partial entecavir response. Compared with the optimal responders, the partial responders had a lower quasispecies complexity and diversity.

CONCLUSIONS

Apart from the known factors (high baseline HBV DNA level and HBeAg positivity), a novel single nucleotide polymorphism (rt124N) and lower quasispecies complexity and diversity were associated with partial entecavir response at year 1.