Factors associated with hepatitis B virus DNA breakthrough in patients receiving prolonged lamivudine therapy

Tenofovir versus lamivudine followed by tenofovir in severe exacerbation of hepatitis B: a randomized controlled study

Spontaneous severe acute exacerbation (SAE) is not uncommon in the natural history of chronic hepatitis B (CHB). Lamivudine (LAM) had the advantages of low price, quick onset, good efficacy and no drug resistance within 24 weeks. This study aimed to compare the short-term efficacy of tenofovir disoproxil fumarate (TDF) and LAM for 24 weeks followed by TDF in the treatment of CHB with severe acute exacerbation. Consecutive patients of CHB with SAE were randomized to receive either TDF (19 patients) or LAM for 24 weeks followed by TDF (18 patients). The primary endpoint was overall mortality or receipt of liver transplantation by week 24. This study was approved by the Institutional Review Board (IRB) of the Kaohsiung Veterans General Hospital (VGHKS12-CT5-10). The baseline characteristics were comparable between the two groups. By week 24, seven (37%) and five (28%) patients in the TDF and LAM/TDF groups died or received liver transplantation (P=0.487). Multivariate analysis showed that albumin level, prothrombin time (PT), and hepatic encephalopathy were independent factors associated with mortality or liver transplantation by week 24. Early reductions in HBV DNA of more than or equal to 2 log at 1 and 2 weeks were similar between the two groups. The biochemical and virological responses at 12, 24 and 48 weeks were also similar between the two groups. TDF and LAM for 24 weeks followed by TDF achieved a similar clinical outcome in CHB patients with SAE.

Sustained antiviral effects and clearance of hepatitis surface antigen after combination therapy with entecavir and pegylated interferon in chronic hepatitis B

BACKGROUND

Although the efficacy of combination therapy with lamivudine or tenofovir and pegylated interferon (PEG-IFN) has been reported in patients with chronic hepatitis B (CHB), the long-term effect of the combination based on the observation of clinical course remains to be clarified. We previously reported the efficacy of combination therapy with entecavir (ETV) and PEG-IFN. Here, we investigated the long-term effect of this combination in patients with CHB.

METHODS

We administered both ETV and PEG-IFN-α2a or -2b simultaneously to 26 patients with HBV genotype C infection. Treatment was continued for 48 weeks followed by 24 weeks of observation period; we examined the virological and biochemical responses. We also analysed characteristics related to the post-treatment relapse. Finally, we investigated the long-term therapeutic effects.

RESULTS

Average reduction of intra-hepatic cccDNA level was 1.2 log copies/μg at the completion of administration. Pretreatment hepatitis B surface antigen (HBsAg) level with more than 3.5 log U/ml was identified as a predictive factor for relapse. Furthermore, the cumulative rates of HBsAg-negative patients at 1, 3 and 5 years after the completion of administration were 3.8, 8.4 and 15%, respectively (mean follow-up period: 4.8 years).

CONCLUSIONS

Baseline HBsAg level with more than 3.5 log U/ml is a useful predictor for relapse 24 weeks after the completion of administration in patients treated with combination therapy. Combination with ETV and PEG-IFN could be an option for treatment of CHB patients especially in those with baseline HBsAg levels of less than 3.5 log U/ml.

Association of virological breakthrough and clinical outcomes in entecavir-treated HBeAg-positive chronic hepatitis B

Background & aims

To evaluate virological breakthrough (VBT) and the risk of hepatocellular carcinoma (HCC) in HBeAg-positive chronic hepatitis B (CHB) patients receiving entecavir (ETV) treatment.

Methods

A retrospective cohort study was conducted in a tertiary referral hospital and a total of 228 HBeAg-positive CHB patients treated with ETV for more than 48 weeks were enrolled. Clinical outcome measures included HBeAg seroclearance, maintained virological response and the development of HCC.

Results

During a median follow-up period of 197 weeks, VBT developed in 26 (11.4%) patients (VBT group), and the other 202 patients without VBT (non-VBT group). The overall cumulative rate of HBeAg seroclearance in the VBT group and non-VBT group were 23.1% and 23.8%, 27.1% and 37.9%, 27.1% and 55.1%, 27.1% and 74.1%, 27.1% and 76.7% from week 48 to 240, respectively(p = 0.013). The cumulative probability of maintained virological responses from week 48 to 240 were 7.69% and 21.78%, 7.69% in the VBT groups and 36.85%, 7.69% and 51.68%, 7.69% and 64.97%, 7.69% and 72.1% in the non-VBT groups, respectively (p<0.001). In the multivariate analysis, age (p<0.001) and virological response at week 24 (p = 0.005) were independently associated with VBT. Cox regression analysis showed that cirrhosis had carried the highest risk for HCC (HR = 4.99, CI = 1.14–21.81, p = 0.033). Subgroup survival analysis by Kaplan–Meier method showed that patients with VBT had higher incidence of developing HCC than without VBT in cirrhotic patients (50% (95%CI = 1–99%) vs 9% (95% CI = 1–9%); p = 0.048).

Conclusions

VBT was associated with adverse clinical outcomes, including a low probability of HBeAg seroclearance, failure to achieve maintained virological responses, and a risk of developing HCC. Patients, particularly with cirrhosis, who had experienced VBT during ETV treatment, more likely developed HCC.

Efficacy of long-term tenofovir disoproxil fumarate therapy in chronic hepatitis B patients with partial virologic response in real practice

BACKGROUND/AIMS

The optimal management of chronic hepatitis B (CHB) patients with partial virologic response (PVR) to tenofovir disoproxil fumarate (TDF) remains unclear. We aimed to evaluate the long-term efficacy of prolonged TDF therapy in treatment-naïve CHB patients with PVR to TDF therapy in real practice.

METHODS

We retrospectively investigated the efficacy of prolonged TDF therapy in treatment-naïve CHB patients with PVR to TDF. PVR was defined as a decrease in serum hepatitis B virus (HBV) DNA over 2 log10 IU/mL from baseline, with detectable HBV DNA by real-time polymerase chain reaction at week 48.

RESULTS

We included 232 patients who underwent TDF therapy for over 48 weeks. Forty-two patients (18.1%) showed PVR. In multivariate analysis, hepatitis B e antigen (HBeAg) positivity, and high levels of serum HBV DNA at baseline and week 12 were independent predictive factors for PVR during TDF therapy. Out of 42 patients with PVR, 39 (92.9%) achieved virologic response (VR) during continuous TDF treatment; the cumulative VR rates at 24, 36, and 48 months were 79.8%, 88.2%, and 95.6%, respectively. With an additional 12 months of therapy, VR was achieved in 28/31 (90.3%) patients with HBV DNA < 100 IU/mL, compared to 5/11 (45.5%) patients with HBV DNA ≥ 100 IU/mL, at week 48.

CONCLUSION

The vast majority of patients achieved VR through prolonged TDF therapy, thus TDF treatment can be maintained in nucleos(t)ide-naïve patients with PVR at week 48, especially in those with low viremia.

Risk factors for resistance development against lamivudine during long-term treatment of chronic hepatitis B virus infections

BACKGROUND/AIM

The use of lamivudine for the treatment of chronic hepatitis B (CHB) is limited by high rates of lamivudine resistance. However, it is still in use in many regions. Factors associated with lamivudine resistance development have been studied in only a few European cohorts. The aim of our study was to assess the rate and risk factors for lamivudine resistance in a large real-life European cohort.

PATIENTS AND METHODS

We retrospectively analyzed patients with CHB treated in three German University centers over up to 12 years. Lamivudine resistance was defined as virologic breakthrough and presence of genotypic lamivudine resistance. The probability of resistance was estimated by Kaplan-Meier analysis and resistance predictors by Cox regression.

RESULTS

A total of 227 patients were included into the analysis (hepatitis B envelope antigen positive or negative). Rates of lamivudine resistance by years 1-7 were 7, 26, 35, 41, 46, 53, and 55%, respectively. Interestingly, two hepatitis B envelope antigen-negative patients developed resistance during the year 12 of treatment. Independent risk factors for resistance development were hepatitis B virus DNA levels of at least 10 copies/ml before and detectable hepatitis B virus DNA by month 6 of treatment.

CONCLUSION

Even after long-term response to lamivudine more than 10 years, resistance may still develop. Our findings further discourage the use of lamivudine for the treatment of CHB.

Is Combination Antiviral Therapy Mandatory for Maintenance Therapy in Fully Suppressed Multidrug-Resistant Hepatitis B Patients?

Aim

The efficacy of tenofovir disoproxil fumarate (TDF) monotherapy as maintenance therapy in multidrug-resistant (MDR) hepatitis B virus (HBV) patients after complete virologic suppression (CVS) has not been well evaluated. We evaluated the efficacy of maintenance TDF monotherapy compared with conventional TDF plus entecavir combination therapy after CVS of MDR HBV.

Methods

In this single-center retrospective study, patients with MDR HBV who were previously treated with entecavir plus TDF combination therapy and achieved CVS were included. Patients were either maintained on entecavir plus TDF combination therapy or switched to TDF monotherapy after CVS. The primary endpoint was the virologic breakthrough, and secondary outcomes were liver cirrhosis (LC) or hepatocellular carcinoma (HCC) development. To overcome immortal time bias, time-varying Cox proportional hazard regression analysis was performed.

Results

A total of 201 patients were included, and 153 patients were maintained on entecavir plus TDF combination therapy (combination group); 48 patients were converted from combination therapy to TDF monotherapy (single group) after CVS. Five patients experienced a virologic breakthrough, one patient in the single group owing to poor transient compliance and four patients in the combination group (P = 0.51). One new case of LC developed in the single group; five cases of LC developed in the combination group (P = 0.35). No new HCC development occurred in the single group, while seven cases of HCC developments were noted in the combination group. However, these results were not statistically significant (P = 0.54).

Conclusions

For patients with suppressed HBV DNA, the efficacy of TDF monotherapy as maintenance therapy is comparable to that of entecavir plus TDF combination therapy.

Step-down strategy in antiviral resistant chronic hepatitis B patients who achieved viral suppression with rescue combination therapy

In the treatment of chronic hepatitis B (CHB) patients with drug resistance, rescue combination therapy leads to viral suppression in almost all patients. However, once it is achieved, lifelong maintenance especially, by using combination therapy is not always possible in a significant proportion of patients. At present, there is no consensus on whether it is possible to switch to monotherapy from combination therapy. However, there is robust evidence to support step-down therapy, which involves switching from combination therapy to monotherapy in antiviral resistant CHB patients who achieve complete viral response from combination therapy. We review the evidence in favor of switching to monotherapy in antiviral resistant CHB patients who achieve complete viral response by combination therapy.

Efficacy of Real-world Entecavir Therapy in Treatment-naïve Chronic Hepatitis B Patients

Background:

Entecavir (ETV) has been shown to be effective in randomized controlled trials in highly selected patients with hepatitis B virus (HBV) infection. This study aimed to evaluate the efficacy of ETV in chronic hepatitis B (CHB) patients in the real-world setting.

Methods:

A total of 233 treatment-naïve, CHB patients who received at least 12 months of ETV treatment were included in this retrospective study. Rates of virological response (VR), hepatitis B s antigen (HBsAg) loss, hepatitis B e antigen (HBeAg) clearance/seroconversion, virological breakthrough, cirrhosis, and hepatocellular carcinoma were evaluated.

Results:

Of 233 patients, 175 patients were male, with mean age of 43 years old, and 135 patients were HBeAg positive. The mean baseline levels of serum alanine aminotransferase and HBV DNA in all patients were 230 U/L and 6.6 log 10 IU/ml, respectively. The mean follow-up period was 28 months. The cumulative rates of achieving VR increased from 3.4% at 3 months to 94.4% at 60 months. Primary nonresponse occurred in 3 (1.3%) patients. Partial VR (PVR) occurred in 61 (26.2%) patients at 12 months. The baseline serum HBV DNA level (hazard ratio [HR], 2.054; P < 0.001) was an independent risk factor for PVR. HBsAg loss did not occur. The cumulative rates of HBeAg clearance increased from 2.2% at 3 months to 28.2% at 60 months. PVR was the significant determinant of HBeAg clearance (HR, 0.341; P = 0.026). Age (HR, 1.072; P = 0.013) and PVR (HR, 5.131; P = 0.017) were the significant determinants of cirrhosis.

Conclusions:

ETV treatment was effective for HBV DNA suppression in this study, but HBsAg loss and HBeAg clearance/seroconversion rates were lower compared with previous clinical trials. PVR was associated with HBeAg clearance and cirrhosis.

Switching from tenofovir and nucleoside analogue therapy to tenofovir monotherapy in virologically suppressed chronic hepatitis B patients with antiviral resistance

It is unclear whether chronic hepatitis B (CHB) patients with antiviral resistance, who achieve a complete virologic response (CVR) with tenofovir disoproxil fumarate (TDF) and nucleoside analogue (NUC) combination therapy, maintain CVR if switched to TDF monotherapy. We investigated the persistence of CVR after cessation of NUC in virologically suppressed antiviral resistant CHB patients using TDF+NUC combination therapy. This study recruited 76 antiviral-resistant CHB patients showing CVR on TDF+entecavir (ETV) (n = 52), TDF+lamivudine (LAM; n = 14), and TDF+telbivudine (LdT; n = 10) combination therapy, who were switched to TDF monotherapy as step-down therapy. At baseline, 47 patients were male and the median age was 53.0 years (range: 30-78 years); 72.3% cases were hepatitis B e antigen-positive (HBeAg+) and 23.7% were of liver cirrhosis. The median duration of TDF+NUC combination therapy was 20.8 months (range: 3-46 months). At a median follow-up of 24.7 months (range: 12-48 months) after switching to TDF monotherapy, all 76 patients maintained CVR, regardless of the duration of combination therapy and the type of prior NUC and antiviral resistance. Renal dysfunction was not observed during the treatment period. The step-down strategy of switching from TDF+NUC combination therapy to TDF monotherapy in virologically suppressed CHB patients with antiviral resistance should be considered.

Clinical Course of Partial Virologic Response with Prolonged Tenofovir Therapy in Nuclos(t)ides-Naïve Patients with Chronic Hepatitis B

BACKGROUND/AIMS

The clinical course of chronic hepatitis B (CHB) patients with partial virologic response (PVR) during tenofovir disoproxil fumarate (TDF) therapy remains unclear.

METHODS

We retrospectively investigated the long-term clinical outcomes of TDF treatment in nucleos(t)ides-naïve CHB patients, particularly in those with PVR.

RESULTS

A total of 391 patients treated with TDF therapy for more than 12 months were included. Virologic response (VR) was achieved in 341 patients (87.2%). PVR was evident in 127 (45.3%) of the 391 patients. Multivariate logistic regression analysis using selected baseline factors identified absolute HBV DNA levels at baseline (OR 0.496; 95% CI 1.369-1.969) and HBeAg positivity (OR 0.622; 95% CI 1.096-3.167) as factors significantly associated with PVR. During continuous prolonged TDF therapy, 127 (71.8%) of 177 patients with PVR achieved VR. The cumulative rates of VR in patients with PVR at 12, 24, and 36 months were 42.4, 79.7, and 90.2%, respectively. Serum HBV DNA level at week 24 was significantly associated with VR in patients with PVR.

CONCLUSIONS

The vast majority of CHB patients with PVR achieved VR through prolonged TDF therapy, although the time to achieve VR was delayed in those with PVR. This suggests that adjustment of TDF therapy in patients with PVR is unnecessary.

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.

Entecavir to Telbivudine Switch Therapy in Entecavir-Treated Patients with Undetectable Hepatitis B Viral DNA

PURPOSE

This study examined 2-year outcome of consecutive therapy using entecavir (ETV) followed by telbivudine (LdT) in subjects with undetectable hepatitis B virus (HBV) DNA level and normal alanine aminotransferase level after the initial 6 months of ETV treatment.

MATERIALS AND METHODS

Sixty subjects were randomized to continue with ETV or switch to LdT. Significant difference in baseline characteristics was not found between the two groups. Persistent HBV DNA level of 20-60 IU/mL in three consecutive samples collected three months apart or singly measured HBV DNA level of >60 IU/mL was defined as virological rebound.

RESULTS

During 96 weeks of follow-up, all subjects of the ETV-only group (n=30) resulted in undetectable HBV DNA level. On the other hand, 83.3% (n=25) of the LdT-switched group showed treatment success. Virological rebound time varied from week 24 to 84 after switching to LdT. HBV DNA level was 180 to 2940 IU/mL at rebound time. All subjects with virological rebound (n=5) showed drug-resistant mutation: three had mutation rtM204I, and two had mutation rtM204V. Consecutive treatment using ETV followed by LdT showed virological rebound in 16.7% of subjects during 96 weeks of follow-up. HBV DNA negativity during initial ETV therapy could not be achieved in patients who switched to LdT.

CONCLUSION

Consecutive treatment using ETV followed by lamivudine was ineffective for treating chronic hepatitis B. LdT was found as a more potent antiviral agent than lamivudine. However, this conclusion requires larger-scale, long-term prospective reviews of the treatment effects of ETV-LdT switch therapy.

On-treatment HBV DNA dynamics predict virological breakthrough in entecavir-treated HBeAg-positive chronic hepatitis B

BACKGROUND & AIMS

Virological breakthrough (VBT) could be a manifestation of chronic hepatitis B (CHB) in patients treated with long-term nucleot(s)ide analogues. We aimed to determine the association of on-treatment serum hepatitis B virus (HBV) DNA with VBT in HBeAg-positive CHB patients receiving entecavir (ETV) treatment.

METHODS

A retrospective cohort study, including 162 consecutive patients (95 men and 67 women; mean age, 43.1±13.4 years) with HBeAg-positive CHB treated with ETV for at least 48 weeks between August 2008 and May 2015, was conducted. Univariate and multivariate cox regression analysis were used to identify associations with VBT and clinical factors, including HBV DNA and HBeAg serum status.

RESULTS

Among the 162 ETV-treated HBeAg-positive CHB patients, eighteen patients (11.1%) experienced VBT (VBT group), whereas the other 144 patients were without VBT (non-VBT group). The cumulative rate of HBV DNA < 100 IU/mL in the VBT group and the non-VBT group at week 48 were 44.44% and 70.14%, and at week 96 were 58.33% and 92.56%, respectively (p = 0.015). The cumulative rate of HBeAg seroclearance in the VBT group and non-VBT group at week 48 and week 96 were statistically significant (p = 0.014). Multivariate analysis disclosed that failure to achieve HBeAg seroclearance were the factors significantly associated with VBT.

CONCLUSIONS

Our results demonstrated that on-treatment HBV DNA could probably predict VBT in ETV-treated HBeAg-positive chronic hepatitis B patients. Failure to achieve HBeAg seroclearance was associated with VBT in ETV-treated HBeAg-positive CHB patients. HBV DNA >100IU/mL at 48 weeks is potentially a predictor for VBT.

Prevalence and risk factors for viral blipping in chronic hepatitis B patients treated with nucleos (t) ide analogues

The clinical relevance of viral blipping during nucleos (t) ide analogue (NA) treatment is unclear in chronic hepatitis B (CHB). We investigated the prevalence, risk factors and clinical outcomes for those with viral blipping during NA treatment. A retrospective cohort study investigated consecutively treated CHB patients from May 2008 to February 2015 on the NAs such as entecavir (ETV), tenofovir (TDF) and lamivudine (LAM). Included patients were previously treatment naive. Viral blipping was defined as serum HBV DNA >20 IU/mL on one occasion, and not >200 IU/mL, with subsequent measurement returning to undetectable levels, that is <20 IU/mL. A total of 242 treatment-compliant CHB patients were included with 44 (18.2%) experiencing viral blipping. In multivariable Cox regression, Asian race (HR=7.40, 95% CI 1.01-54.29, P<.049), LAM therapy (vs ETV/TDF, HR=2.53, 95% CI 1.29-4.95, P<.007), higher creatinine (per SD, HR=1.47, 95% CI 1.21-1.79, P<.001), HBeAg positivity (HR=2.68, 95% CI 1.39-5.03, P<.003) and longer time to achieve undetectable HBV DNA (per month, HR=1.05, 95% CI 1.02-1.08, P=.001) were associated with an increased risk of viral blipping. Viral blipping did not show any significant association with viral breakthrough, HBsAg loss, ALT flares or disease progression. Viral blipping is a frequent event during NA therapy; however, it did not lead to any clinically significant outcomes. Thus, it may not require more frequent blood work and patient visits in clinical practice.

Lamivudine-resistant rtL180M and rtM204I/V are persistently dominant during combination rescue therapy with entecavir and adefovir for hepatitis B

Adefovir (ADV) sequential monotherapy was included in the 2005 Asia-Pacific guidelines for the management of patients with lamivudine (LAM) resistance. However, following the development of ADV resistance, the proportion of resistant variants during combined rescue therapy with ADV and entecavir (ETV) were unknown. The present study characterized the dynamics of resistant variants in patients with chronic hepatitis B (CHB) and LAM-resistant variants during antiviral therapy consisting of ADV monotherapy followed by ADV-ETV combination therapy. A total of 3 patients were selected from a cohort of 55 patients with CHB due to developing ADV resistance. The patients had been previously treated with LAM (100 mg daily) for 21–24 months. At the initiation of sequential monotherapy with ADV, LAM-resistant variants (rtM204V/I and rtL180M) were detected in the three patients. These patients developed ADV resistance during 19–30 months of ADV sequential monotherapy, and then switched their antiviral regimen to ADV-ETV combination therapy. During ADV monotherapy and ADV-ETV combination therapy, the patients were monitored every 3 months for the first year of therapy, and then every 6 months thereafter. A total of 30 serum samples were collected from the patients throughout the monitoring period. In total, 10 mutants that were associated with commonly-used antiviral drugs were detected by pyrosequencing. During ADV sequential monotherapy, LAM-resistant variants were gradually decreased, whereas ADV-resistant rtA181V/T and rtN236T variants gradually increased in the viral population. During 30–41 months of ADV-ETV combination therapy, viral load reduction was 2.59–3.28 log₁₀ copies/ml; ADV-resistant variants rtA181T/V and rtN236T were undetectable following 11–24 months of combination therapy; and rtL180M and rtM204I/V remained dominant in the viral population. In conclusion, the results of the present study suggested that, in patients with LAM and ADV-resistant variants that developed during LAM-ADV sequential monotherapy, ETV-ADV combination therapy may partially inhibit the replication of HBV DNA; however, LAM-resistant rtL180M and rtM204I/V variants remained predominant following 30–41 months combination therapy.

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.

Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update

Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.

Dynamics of Genotypic Mutations of the Hepatitis B Virus Associated With Long-Term Entecavir Treatment Determined With Ultradeep Pyrosequencing: A Retrospective Observational Study

The aim of the study is to explore the evolution of genotypic mutations within the reverse transcriptase region in partial virological responders (PVRs) receiving long-term entecavir (ETV) treatment. A total of 32 patients were classified as completely virological responders (CVRs) (n = 12) or PVRs (n = 20). Five partial responders were hepatitis B virus (HBV)-DNA positive after long-term therapy, which lasted for >3 years. A total of 71 serum samples from these 32 patients were assayed by ultra-deep pyrosequencing (UDPS): 32 samples were from all patients at baseline, and 39 were from PVRs with sequential inter-treatment. Approximately 84,708 sequences were generated per sample. At baseline, the quasispecies heterogeneity did not significantly differ between the 2 groups. The frequencies of substitutions indicating pre-existence of nucleos(t)ide analog resistant (NAr) mutants ranged from 0.10% to 6.70%, which did not statistically differ between groups either. However, the substitutions associated with the NAr mutants were significantly different from those associated with the non-NAr mutants in 13 patients; 6 of these patients were PVRs and the others were CVRs. Five patients were HBV DNA positive after regular ETV monotherapy for >3 years, and 4 of these patients underwent mild NAr substitution fluctuations (<20%). One patient developed virological breakthrough while bearing single, double, and triple (rtL180 M, rtM204 V, rtS202G) substitutions. In addition to the common substitutions, unknown amino acid substitutions, such as rtL145 M/S, rtF151Y/L, rtR153Q, rtI224 V, rtN248H, rtS223A, rtS256C, need to be further verified. NAr substitutions are observed at frequencies of 0.10% to 6.7% before therapy. Long-term ETV therapy generally results in virological responses, as long as the proportion of resistance mutations remains at a relatively low level. Genotypic resistance to ETV is detected in all PVRs receiving long-term ETV therapy.

Antiviral therapy for chronic hepatitis B: Combination of nucleoside analogs and interferon

The ideal goal of chronic hepatitis B (CHB) treatment should be suppression of emergence of hepatocellular carcinoma through the disappearance of hepatitis B s antigen (HBsAg) rather than the control of serum hepatitis B virus-DNA level. For this purpose, various types of combination therapies using nucleoside analogs (NAs) and interferon (IFN) have been conducted. The therapeutic effects of combination of two different kinds of agents are better than those of the monotherapy using NAs or IFN alone, probably because different pharmaceutical properties might act in a coordinated manner. Recently, combination therapies with NAs and IFN and sequential therapies with NAs administration followed by IFN therapy have been routinely employed. We previously reported that combination therapy using entecavir (ETV) and pegylated (PEG)-IFN showed antiviral effects in 71% of CHB patients; the effect of this combination was better than that using lamivudine (LAM) and PEG-IFN. This is partially explained by the better antiviral effects of ETV than those of LAM. In our analysis, the cohort of CHB consisted of the patients who showed a flare-up of hepatitis before antiviral therapy, and their baseline HBsAg levels were relatively low. Therefore, in addition to the combination of the agents, the appropriate selection of patients is critical to achieve a good viral response.

Partial virological response to entecavir treatment in nucleos(t)ide-naïve patients with HBeAg-positive chronic hepatitis B is not caused by reduced sensitivity

Some patients with chronic hepatitis B (CHB) receiving entecavir (ETV) exhibit partial virological response (PVR) to ETV and the mechanism is not clear. In this study, we aim to investigate the in vitro susceptibility of residual clinical strains isolated from the sera of nucleos(t)ide-naïve hepatitis B virus e antigen (HBeAg)-positive patients with CHB and PVR to ETV, and to evaluate the clinical and virological responses to prolonged ETV monotherapy in these patients. We followed 69 nucleos(t)ide-naïve HBeAg-positive CHB patients receiving ETV treatment, with 13 partial responders to ETV. And we found that no genotypic resistance mutants were detected among the 13 PVR patients. Phenotypic analysis revealed that the residual HBV strains had normal replication capacity, and were as susceptible to ETV as wild-type HBV. All PVR patients continued to receive ETV monotherapy, and serum HBV DNA of the majority became undetectable after prolonged treatment. However, none of these patients achieved HBeAg loss. In contrast, 25.6% and 23.2% of the patients with virological response achieved HBeAg loss (P < 0.001) and HBeAg seroconversion (P < 0.001) at week 144, respectively. Thus, we conclude suboptimal response to ETV might not be due to reduced HBV susceptibility to ETV, and prolonging ETV monotherapy in patients with PVR is recommended.

Clinical course of partial virological responders under prolonged entecavir monotherapy in patients with chronic hepatitis B

Studies about long-term entecavir (ETV) therapy for partial virological response (PVR) are lacking. This study aimed to assess the clinical course of PVR patients receiving ETV therapy and analyze the efficacy of tenofovir (TDF). We retrospectively evaluated 130 patients who showed a PVR to ETV. Among these patients, 102 were nucleot(s)ide analogue (NUC)-naïve and 28 were lamivudine (LAM)-experienced. The cumulative rates of VR were 54.1%, 70.8%, and 83.7% for the NUC-naïve group and 37.0%, 42.8%, and 42.8% for the LAM-experienced group after 24, 36, and 48 months of ETV therapy, respectively (P  = 0.008). Low HBV DNA level at 12 months (P < 0.001) and absence of a LAM treatment history (P  = 0.031) were significant associated factors for VR. In VR prediction at 36 months of ETV therapy in NUC-naïve patients, HBV DNA level <95 IU/ml at 12 months showed a 92.9% sensitivity and a 78.3% specificity (AUROC, 0.909; P < 0.001). ETV resistance did not develop in NUC-naïve patients with HBV DNA levels <95 IU/ml at 12 months. The cumulative probability of VR in patients who switched to or additionally received TDF was 91.3% at 15 months. Prolonged ETV therapy induced a VR without the risk of ETV resistance in NUC-naïve patients with HBV DNA levels <95 IU/ml at 12 months. All patients with LAM-experienced or NUC-naïve with HBV DNA levels ≥95 IU/ml at 12 months should be switched to TDF rescue therapy.

Performance of LigAmp assay for sensitive detection of drug-resistant hepatitis B virus minor variants in comparison with standard nucleotide sequencing

BACKGROUND AND OBJECTIVES

A virus population often exists as a complex mixture of genetic populations. Antiviral-resistant mutants could be circulating as minority variants in the mixed virus population that are not detected by standard sequencing methods. The role of minor drug-resistant variants and clinical outcome is slowly evolving and there is a need to employ sensitive methods for detection of minority variants that emerge as dominant species and subsequently affect the antiviral efficacy. This study was intended to develop a technique called the ligation amplification assay (LigAmp) to identify minor drug-resistant variants of hepatitis B virus (HBV).

METHODS

A LigAmp HBV assay was developed and clinical samples were tested from chronic hepatitis B subjects on antiviral treatment. Nucleotide sequencing of HBV reverse transcriptase (rt) region was performed and the results were compared with LigAmp assay. The performance of LigAmp assay was validated by clonal sequencing. Virological response was measured using HBV DNA levels and the results were correlated with antiviral-resistant mutations detected by sequencing and LigAmp assays.

RESULTS

A total of 80 reactions of LigAmp assay were performed for rtM204V and rtM204I (ATT) mutant detection. Samples were obtained from 40 chronic hepatitis B subjects. Among these subjects, rtM204V and rtM204I (ATT) mutations were identified by standard sequencing in 10 (25%) and 12 (30%) subjects, respectively. LigAmp detected both rtM204V and rtM204I (ATT) mutations in 13 (32.5%) subjects, rtM204I mutation in 12 (30%) subjects and rtM204V mutation in 1 (2.5%) subject, respectively. LigAmp detected primary resistant mutants in 69.4% of lamivudine non-responders while sequencing detected resistant mutations in only 55.6% subjects (p < 0.001).

CONCLUSIONS

This data shows significantly higher sensitivity of LigAmp for detection of minority rtM204V and rtM204I (ATT) mutations over standard sequencing. Therefore, LigAmp has potential clinical utility for appropriate monitoring and tailoring of HBV therapy.

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.

Rethinking the pathogenesis of hepatitis B virus (HBV) infection

Chronic hepatitis B virus (HBV) infection affects approximately 375 million people worldwide. Current antiviral treatment effectively controls, but rarely clears chronic HBV infection. In addition, a significant portion of chronic HBV infected patients are not suitable for currently available antiviral therapy, and still face higher risk for cirrhosis and hepatocellular carcinoma. The poorly understood pathogenesis of HBV infection is the main barrier for developing more effective treatment strategies. HBV has long been viewed as non-cytopathic and the central hypothesis for HBV pathogenesis lies in the belief that hepatitis B is a host specific immunity-mediated liver disease. However, this view has been challenged by the accumulating experimental and clinical data that support a model of cytopathic HBV replication. In this article we systematically review the pathogenic role of HBV replication in hepatitis B and suggest possible HBV replication related mechanisms for HBV-mediated liver injury. We propose that a full understanding of HBV pathogenesis should consider the following elements. I. Liver injury can be caused by high levels of HBV replication and accumulation of viral products in the infected hepatocytes. II. HBV infection can be either directly cytopathic, non-cytopathic, or a mix of both in an individual patient depending upon accumulation levels of viral products that are usually associated with HBV replication activity in individual infected hepatocytes.

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.

High treatment modification rates with lamivudine therapy in HBV-infected patients with low baseline viremia and early virological response: A multicenter study

OBJECTIVE

Low baseline viremia and an early treatment response predict the best outcomes in hepatitis B virus (HBV)-infected patients treated with nucleoside analogues with low barriers to resistance. The aim of this study was to assess the long-term results and effectiveness of lamivudine in patients with low baseline viremia and early virological treatment response.

METHODS

In this multicenter, real-life setting study, 111 antiviral-naive patients with low baseline viremia (HBV DNA <10(7) copies/mL) plus an early virological response (HBV DNA <300 copies/mL at week 24) treated with lamivudine were enrolled. The primary end-point was treatment failure, defined as the re-emergence of detectable viremia or at least a 1 log increase in HBV DNA, resulting in a titer of ≥ 300 copies/mL with lamivudine treatment after week 24, which required treatment modification.

RESULTS

Altogether 111 patients, including 78 non-cirrhotic and 33 cirrhotic patients, were included in the study. Treatment failure occurred in 30.8% of the non-cirrhotic patients over a median follow-up period of 32.5 months, and the 1-, 2-, 3-, 4- and 5-year treatment failure rates were 6.5%, 14.0%, 31.4%, 39.6% and 43.1%, respectively. Treatment failure occurred in 28.8% of the whole group. There were no differences between the cirrhotic and non-cirrhotic patients.

CONCLUSIONS

Lamivudine treatment had a high treatment modification rate in patients with low baseline viremia and early virological response over a long-term follow-up in a real-life setting. The pretreatment and on-treatment favorable characteristics found in the studies with telbivudine appeared to be inapplicable to lamivudine.

Lamivudine resistance in children with chronic hepatitis B

Currently, although lamivudine (LAM) has a low genetic barrier, only interferon-alpha and LAM are available as a first-line treatment in children with chronic hepatitis B (CHB). LAM is a potent inhibitor of hepatitis B virus-deoxyribonucleic acid (HBV-DNA) polymerase replication by termination of the proviral HBV-DNA chain. LAM has a good safety and tolerability profile in CHB patients with hepatic decompensation. However, the main disadvantages of this HBV reverse transcriptase inhibitor are: (1) pre-existing covalently closed circular DNA cannot be eradicated by LAM, thus relapse after therapy withdrawal is frequent; and (2) although the longer LAM treatment induced the higher seroconversion rate, the risk of viral resistance increased through the selection of YMDD (tyrosine, methionine, aspartate, aspartate) motif. Insufficient suppression of viral replication leads to the emergence of resistant strains that could result in virological breakthrough which is usually followed by biochemical breakthrough. Mutant strains affects additional resistance and cross resistance, leading to drug resistance in a significant number of CHB patients. In this case, efficacy of more powerful anti-viral agents with higher genetic barrier against development of resistance is diminished. Furthermore, strains that are resistant to LAM could bring about vaccine escape mutants, decreasing the efficacy of HBV vaccine. A more potent drug with a high genetic barrier to resistance needs to be approved as the first-line treatment option for CHB in children.

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.

Delayed Reduction of Hepatitis B Viral Load and Dynamics of Adefovir-Resistant Variants during Adefovir plus Entecavir Combination Rescue Therapy

OBJECTIVE

Entecavir (ETV) added to adefovir (ADV) is recommended in the consensus for management of patients with ADV resistance. However, little attention has been focused on the delayed reduction of HBV DNA and dynamics of ADV-resistant variants during ADV-ETV combination rescue therapy in the clinical setting. We characterized the dynamics of viral load and resistant variants in nucleos(t)ide analogues (NAs)-naïve chronic hepatitis B (CHB) patients during antiviral treatment with ADV monotherapy followed by ADV-ETV combination therapy.

METHODS

A cohort of 55 CHB patients was enrolled in this study. Three NAs-naïve patients developed ADV-resistant variants during 24-33 months of ADV monotherapy, and then switched to ADV-ETV combination therapy. Thirty-five serial serum samples from these three patients were regularly collected during treatment. Ten mutants associated with commonly used antiviral drugs were detected by pyrosequencing.

RESULTS

HBV DNA decreased to the lowest level during ADV monotherapy at 6-18 months, with a decrease of 0.95-5.51 log10 copies/mL, whereas rtA181V or rtN236T gradually increased with extended therapy. HBV DNA decreased to below the detectable level during ADV-ETV combination therapy at 21-24 months, with a decrease of 4.19-4.65 log10 copies/mL. Resistant rtA181V and rtN236T were undetectable after 21-24 months of combination therapy. Moreover, no LAM-resistant rtM204I/V or ETV-resistant variants were detected during the 27-36 months of combination therapy.

CONCLUSION

Although ADV-resistant variants were suppressed, viral load reduction was delayed during ADV-ETV combination rescue therapy in patients with ADV-resistant HBV. The quantification of resistant variants by pyrosequencing may facilitate monitoring of antiviral therapy.

Partial virological response to three different nucleotide analogues in naive patients with chronic hepatitis B

BACKGROUND

The definition of partial virological response (PVR) was proposed because of its clinical relevance. PVR relates to subsequent therapeutic failure which results in the modification of the regimen. Whether this rationale can be applied to all nucleotide analogues (NA) is not clear. This study was undertaken to analyze PVR influence on therapeutic outcomes during lamivudine, entecavir or tenofovir monotherapy in NA-naive patients with chronic hepatitis B in routine clinical practice.

METHODS

We retrospectively analyzed 150 NA-naive patients with chronic hepatitis B. These subjects received lamivudine, entecavir or tenofovir monotherapy between February 2001 and July 2013.

RESULTS

Sixty-nine patients were treated with lamivudine, 35 with entecavir, and 46 with tenofovir. The median therapeutic duration was 19.5 (6-147) months. PVR rates at 24 weeks were similar among three NAs (lamivudine 33.3%, entecavir 35.0%, tenofovir 32.4%, P=0.981). For all three NAs, patients with a higher baseline viral load or HBeAg-positive status had a higher serum viral positive rate tested by polymerase chain reaction at week 24 and 48. Cumulative probability of virological breakthrough (VBR) for patients treated with lamivudine was 67% at 5 years, and PVR at 24 weeks was the independent risk factor for VBR (HR: 3.09; 95% CI: 1.09-8.74; P=0.034); also lamivudine treated patients older than 50 years seemed to have a tendency for VBR (HR: 2.80; 95% CI: 0.99-8.18; P=0.052). A majority of entecavir and tenofovir partial responders achieved and maintained virological response with prolonged monotherapy, except one entecavir treated patient who experienced VBR due to resistance mutations.

CONCLUSIONS

Management strategy for lamivudine treatment should include adaptation of regimen according to PVR as an on-treatment response parameter due to its relation with unacceptably high VBR probability. Similar conclusion should not be directly related to entecavir or tenofovir treatment.

Prediction of prognosis to lamivudine in patients with spontaneous reactivation of hepatitis B virus-related acute-on-chronic liver failure: using virologic response at week 4

BACKGROUND/AIMS

Current results had demonstrated lamivudine (LAM) contributed to improve liver function and short-term prognosis in patients with hepatitis B virus-related acute-on-chronic liver failure (ACLF), but data concerning the outcome of long-term prognosis are limited. Our objective was to explore the prediction value of early viral response for prognosis and LAM resistance in ACLF patients with lamivudine treatment within 96weeks.

METHODS

One hundred and forty consecutive subjects were recruited, 76 patients were treated with LAM and supportive treatment (LAM group) and 64 patients only received supportive treatment (non-NAs group). All the patients were followed up until death or 96weeks. The primary end point was overall survival rate at 96weeks, as well as the relationship between the virologic response at weeks 4 or 12 and prognosis and resistance at 96weeks.

RESULTS

At 96weeks, the cumulative survival was higher in the LAM group than that in the non-NA group (43/76 (56.58%) vs 9/64 (14.06%), respectively, p=0.000). The survival rate of patients achieved complete viral response (CVR) at week 4 was higher than that of those with partial virologic response (PVR) during the 96-week follow-up (27/29 [93.10%] vs 16/45 [35.56%], p=0.000). In CVR patients, there was a significant improvement in model for end-stage liver failure (MELD) scores compared to PVR. Logistic recurrence indicated that both 4-week CVR and MELD scores were an independent predictor of the 96-week survival. Twelve patients developed LAM resistance (22.22%); all of them came from the PVR at 4weeks.

CONCLUSION

LAM can significantly improve the long-term survival rate, and 4weeks CVR can predict the long-term clinical outcome and LAM-resistant in patients with HBV-related ACLF.

Lamivudine treatment failure risks in chronic hepatitis B patients with low viral load

AIM

To analyze the risk factors of lamivudine treatment failure (LTF) for the long-term use in patients with low viral load (LVL).

MATERIAL AND METHODS

In this multicenter study, 548 antiviral naïve noncirrhotic adult patients with LVL (for HBeAg+ patients HBV DNA <10 9 copies/ml and for HBeAg–patients HBV DNA <10 7 copies/ml) were enrolled. As a control group, 46 lamivudine-initiated patients with high viral load (HVL) were included. Primary outcome was switching to or adding on another antiviral drug as a consequence of primary nonresponse, partial response, viral breakthrough or adverse events. Secondary outcomes included LTF rates at 1, 2, 3, 4 and 5 years and LTF-related viral and host factors.

RESULTS

Among 594 patients, 294 had to change lamivudine at the follow-up. Primary nonresponse, partial response, viral breakthrough or adverse events frequencies were 6.8, 1.6, 64.5 and 0.1%, respectively. Five-year LTF rates were 61.3 and 84.2% in patients with LVL and HVL, respectively. Among patients with LVL, patients with <100,000 copies/ml and ≥ 100,000 copies/ ml had 54.8 and 67.3% LTF rates at the end of the 5th year, respectively. Logistic regression analysis of risk factors showed HBeAg+, hepatic activity index, HBV DNA, virological response at 6 months and duration of follow-up were independent predictors for LTF (p values were 0.001, 0.008, 0.003, 0.020 and 0.003, respectively).

CONCLUSION

Similar to patients with HVL, first-line lamivudine therapy is not efficient for long-term use in patients with LVL. LTF risk is so high even in the absence of worse predictive factors.

Management of antiviral drug resistance in chronic hepatitis B

Rescue antiviral treatment for patients with resistance to preexisting nucleos(t)ide analogues remains a clinical challenge. The correct choice of a first-line treatment of high potency and with a high genetic barrier to achieve sustained long-term suppression of viral replication provides the best chance of preventing treatment failure and the emergence of drug resistance. The management of treatment failure and drug resistance requires a precise and accurate clinical and virologic monitoring. Combination treatment with antiviral drugs that belong to different groups is associated with a lower chance of developing resistance to rescue drugs. To guarantee better control of viral replication in patients with drug resistance, the addition of another drug without a cross resistance profile should be given as early as possible, preferably at the time when genotypic resistance emerges. Long-term surveillance for treatment efficacy and possible emergence of drug resistance should be continued to prevent the emergence of multidrug-resistant strains.

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.

Efficacy of entecavir-tenofovir combination therapy for chronic hepatitis B patients with multidrug-resistant strains

The emergence of multidrug-resistant (MDR) strains of hepatitis B virus (HBV) is a major concern. This study aimed to investigate the efficacy and safety of combination therapy with entecavir (ETV) plus tenofovir disoproxil fumarate (TDF) against MDR HBV. To adjust for differences in baseline characteristics, inverse probability weighting (IPW) using propensity scores for the entire cohort and weighted Cox proportional hazards models were applied. Ninety-three consecutive patients who were treated with ETV-TDF combination therapy for >6 months were included; at baseline, 45 were infected with HBV strains with genotypic resistance to lamivudine (LAM) and ETV (the LAM/ETV-R group), 28 with strains resistant to LAM and adefovir (ADV) (the LAM/ADV-R group), and 20 with strains resistant to LAM, ETV, and ADV (the LAM/ETV/ADV-R group). The median duration of rescue therapy was 13.0 (range, 6.7 to 31.7) months. Seventy-four of 93 patients (79.6%) achieved complete virologic suppression, after a median of 4.5 (95% confidence interval, 3.0 to 6.0) months. The cumulative probability of complete virologic suppression at month 6 was 63.6% (55.7%, 75.0%, and 65.0% in the LAM/ETV-R, LAM/ADV-R, and LAM/ETV/ADV-R groups, respectively). During the treatment period, these probabilities were not significantly different across the resistance profiles before and after IPW (P = 0.072 and P = 0.510, respectively). In multivariate analysis, a lower baseline HBV DNA level, but not resistance profiles, was an independent predictor of complete virologic suppression. Renal dysfunction was not observed during the treatment period. In conclusion, rescue therapy with ETV-TDF combination is efficient and safe in patients infected with MDR HBV strains regardless of the antiviral drug resistance profiles.

Efficacy of entecavir-tenofovir combination therapy for chronic hepatitis B patients with multidrug-resistant strains

The emergence of multidrug-resistant (MDR) strains of hepatitis B virus (HBV) is a major concern. This study aimed to investigate the efficacy and safety of combination therapy with entecavir (ETV) plus tenofovir disoproxil fumarate (TDF) against MDR HBV. To adjust for differences in baseline characteristics, inverse probability weighting (IPW) using propensity scores for the entire cohort and weighted Cox proportional hazards models were applied. Ninety-three consecutive patients who were treated with ETV-TDF combination therapy for >6 months were included; at baseline, 45 were infected with HBV strains with genotypic resistance to lamivudine (LAM) and ETV (the LAM/ETV-R group), 28 with strains resistant to LAM and adefovir (ADV) (the LAM/ADV-R group), and 20 with strains resistant to LAM, ETV, and ADV (the LAM/ETV/ADV-R group). The median duration of rescue therapy was 13.0 (range, 6.7 to 31.7) months. Seventy-four of 93 patients (79.6%) achieved complete virologic suppression, after a median of 4.5 (95% confidence interval, 3.0 to 6.0) months. The cumulative probability of complete virologic suppression at month 6 was 63.6% (55.7%, 75.0%, and 65.0% in the LAM/ETV-R, LAM/ADV-R, and LAM/ETV/ADV-R groups, respectively). During the treatment period, these probabilities were not significantly different across the resistance profiles before and after IPW (P = 0.072 and P = 0.510, respectively). In multivariate analysis, a lower baseline HBV DNA level, but not resistance profiles, was an independent predictor of complete virologic suppression. Renal dysfunction was not observed during the treatment period. In conclusion, rescue therapy with ETV-TDF combination is efficient and safe in patients infected with MDR HBV strains regardless of the antiviral drug resistance profiles.

Application of coamplification at lower denaturation temperature-PCR sequencing for early detection of antiviral drug resistance mutations of hepatitis B virus

Nucleoside/nucleotide analogue for the treatment of chronic hepatitis B virus (HBV) infection is hampered by the emergence of drug resistance mutations. Conventional PCR sequencing cannot detect minor variants of <20%. We developed a modified co-amplification at lower denaturation temperature-PCR (COLD-PCR) method for the detection of HBV minority drug resistance mutations. The critical denaturation temperature for COLD-PCR was determined to be 78°C. Sensitivity of COLD-PCR sequencing was determined using serially diluted plasmids containing mixed proportions of HBV reverse transcriptase (rt) wild-type and mutant sequences. Conventional PCR sequencing detected mutations only if they existed in ≥25%, whereas COLD-PCR sequencing detected mutations when they existed in 5 to 10% of the viral population. The performance of COLD-PCR was compared to conventional PCR sequencing and a line probe assay (LiPA) using 215 samples obtained from 136 lamivudine- or telbivudine-treated patients with virological breakthrough. Among these 215 samples, drug resistance mutations were detected in 155 (72%), 148 (69%), and 113 samples (53%) by LiPA, COLD-PCR, and conventional PCR sequencing, respectively. Nineteen (9%) samples had mutations detectable by COLD-PCR but not LiPA, while 26 (12%) samples had mutations detectable by LiPA but not COLD-PCR, indicating both methods were comparable (P = 0.371). COLD-PCR was more sensitive than conventional PCR sequencing. Thirty-five (16%) samples had mutations detectable by COLD-PCR but not conventional PCR sequencing, while none had mutations detected by conventional PCR sequencing but not COLD-PCR (P < 0.0001). COLD-PCR sequencing is a simple method which is comparable to LiPA and superior to conventional PCR sequencing in detecting minor lamivudine/telbivudine resistance mutations.

Optimization therapy for the treatment of chronic hepatitis B

Chronic hepatitis B (CHB) is currently medically managed with either interferon-alpha or one of the five nucleos(t)ide analogs. However, there are still a large number of CHB patients whose response to the above therapies remains less than satisfactory, and their incomplete or non-response to antiviral therapies has plagued clinicians worldwide. In recent years, a newly proposed optimization therapy has provided us with a new approach to solve this problem. The key points in this optimization therapy are to initiate antiviral therapy with an appropriate agent at the correct time point, and to adjust treatments in patients with poor early responses by adding a second agent or switching to another more potent agent. In this review, we summarize recent developments in optimization therapy for the treatment of CHB, and provide an outlook for future research in this field.

Chronic hepatitis B virus infection: epidemiology, prevention, and treatment in China

Chronic hepatitis B is a major health problem in China. The universal vaccination program since 1992 has changed the epidemiology of hepatitis B virus infection in China from highly to moderately endemic. The most prevalent hepatitis B virus strains in China are genotypes B and C, whereas those in western provinces are genotypes D and C/D hybrid. Chronic hepatitis B poses a heavy burden to the society in China. Different treatment strategies have been explored to improve patient outcomes in a cost-effective manner. However, antiviral drugs with a low genetic barrier to resistance are still extensively used because of the generally low income and limited resources in China. Individualized antiviral therapy is closely associated with translational medicine, which utilizes information from studies on genomics, immune biomarkers, and fibrosis. The results of these studies are crucial in further improving treatment outcomes.

Changes of HBsAg and HBV DNA levels in Chinese chronic hepatitis B patients after 5 years of entecavir treatment

BACKGROUND AND AIM

Hepatitis B surface antigen (HBsAg) kinetics during long-term entecavir therapy has not been well investigated.

METHODS

We described the cumulative serologic, virologic, and biochemical outcomes and the occurrence of signature entecavir mutations among 222 Chinese treatment-naïve chronic hepatitis B (CHB) patients receiving entecavir for up to 5 years.

RESULTS

The median rate of HBsAg reduction over 5 years was 0.125 log IU/mL/year. Patients with high baseline HBV DNA levels (≥ 8 log copies/mL or ≥ 7.3 log IU/mL), when compared with those with baseline hepatitis B virus (HBV) DNA < 7.3 log IU/mL, had a significantly greater median rate of HBsAg reduction (0.178 and 0.102 log IU/mL/year, respectively, P < 0.001). The difference in HBsAg decline was most prominent in the first year (0.324 and 0.062 log IU/mL/year, respectively, P < 0.001). Greater median rates of HBsAg reduction were also found in hepatitis B e antigen (HBeAg)-positive patients when compared with HBeAg-negative patients (0.144 and 0.098 log IU/mL/year, P = 0.015), and in patients with high baseline HBsAg levels (≥ 3 log IU/mL), when compared with patients with low baseline HBsAg < 3 log IU/mL (0.131 and 0.045 log IU/mL/year, respectively, P = 0.001). The 5-year cumulative rate of HBV DNA undetectability (< 20 IU/mL) was 97.1%. There were two cases of entecavir resistance, resulting in a 5-year cumulative resistance rate of 1.2%.

CONCLUSION

In contrast to the profound HBV DNA suppression, long-term entecavir treatment achieved only a slow decline in serum HBsAg. Although certain patient subgroups exhibit a more rapid HBsAg reduction, additional therapeutic agents are needed to increase the chance of HBsAg seroclearance in CHB.

Assessment of current criteria for primary nonresponse in chronic hepatitis B patients receiving entecavir therapy

A primary nonresponse to oral drugs against hepatitis B virus (HBV) is a generally accepted criterion for interrupting treatment. We investigated whether the concept of primary nonresponse suggested by current American (AASLD) and European (EASL) guidelines is appropriate for treatment with entecavir (ETV). The study included 1,254 treatment-naïve patients who had pretreatment HBV DNA levels of >2,000 IU/mL and received ETV 0.5 mg/day for over 6 months. "Primary nonresponse" was defined as a <2 log drop in HBV DNA after 6 months of therapy by AASLD and as a <1 log drop after 3 months by EASL. The cumulative probability of virological response (VR; HBV DNA of <15 IU/mL) was compared in patients with and without primary nonresponse. Median time to achieve VR was significantly shorter in primary responders by AASLD than nonresponders (12 versus 24 months; P = 0.004), but the cumulative probability of achieving a VR at 54 months was similar in the two groups (95.8% versus 100%). Time to achieve a VR and cumulative probability of VR over time did not differ between primary responders and nonresponders by EASL. On-treatment virological breakthrough occurred in 18 patients with a cumulative rate of 5.6% at 72 months. ETV resistance was detected in 13 of these 18 patients (72.2%), who were all classified as primary responder according to both guidelines.

CONCLUSION

Long-term ETV therapy generally leads to a VR in treatment-naïve patients, although the time to achieve it is delayed in primary nonresponders. The current recommendation to change therapy in primary nonresponders needs to be modified to reflect drug differences in antiviral potency and resistance risk.

Efficacy and resistance in de novo combination lamivudine and adefovir dipivoxil therapy versus entecavir monotherapy for the treatment-naive patients with chronic hepatitis B: a meta-analysis

Background

Currently, there is no consensus on the efficacy and resistance of de novo combination therapy versus monotherapy for treatment naive patients of chronic hepatitis B (CHB).

Objectives

The aim of this study was to evaluate the effectiveness and resistance of de novo combination of lamivudine (LAM) and adefovir dipivoxil (ADV) compared with entecavir (ETV) monotherapy for nucleos(t)ide–naive patients with CHB.

Study design

Publications on the effectiveness and resistance of LAM plus ADV versus ETV monotherapy for nucleos(t)ide-naive patients with CHB were identified by a search of PubMed, Embase, the Cochrane Library, Web of science, OVID, and CBM (Chinese Biological Medical Literature) until May 1, 2013. Biochemical response, hepatitis B e antigen seroconversion, and viroligic response were extracted and combined to obtain an integrated result. Viral resistance and safety were reviewed.

Results

Five eligible studies (328 patients in total) were included in the analysis. LAM plus ADV combination therapy produced more rapid HBV DNA reduction rate at 12 weeks than that of ETV monotherapy. At 48 weeks, the combination group had superior viroligic response rates compared with ETV group (90.0% vs. 78.9%, P=0.01). The difference in the ALT normalization and HBeAg seroconversion rates was not found. At week 96, LAM + ADV was more effective than ETV in ALT normalization [RR = 1. 11, 95% CI (1.02, 1.21), P =0.01] and HBeAg seroconversion [RR = 2.00, 95% CI (1.26, 3.18, P=0.003)], and no significant difference was found in the virologic response (P =0.23). No viral resistance occurred in combination therapy and six patients in ETV group were experienced with viral breakthrough. Both groups were well tolerated.

Conclusion

The de novo LAM plus ADV combination therapy for treatment-naïve patients with CHB was greater than ETV monotherapy in both biochemical response and HBeAg seroconversion rate up to 96 weeks. The rate of emergence of viral resistance in the combination group was less than that in the ETV monotherapy.

Then and now: The progress in hepatitis B treatment over the past 20 years

The ultimate goals of treating chronic hepatitis B (CHB) is prevention of hepatocellular carcinoma (HCC) and hepatic decompensation. Since the advent of effective antiviral drugs that appeared during the past two decades, considerable advances have been made not only in controlling hepatitis B virus (HBV) infection, but also in preventing and reducing the incidence of liver cirrhosis and HCC. Furthermore, several recent studies have suggested the possibility of reducing the incidence of recurrent or new HCC in patients even after they have developed HCC. Currently, six medications are available for HBV treatment including, interferon and five nucleoside/nucleotide analogues. In this review, we will examine the antiviral drugs and the progresses that have been made with antiviral treatments in the field of CHB.

Early entecavir treatment for chronic hepatitis B with severe acute exacerbation

A previous study found that lamivudine, if started early enough, may improve the chance of survival in chronic hepatitis B virus (HBV) with severe acute exacerbation (SAE). The aim of this study was to investigate the effect of early entecavir treatment before the bilirubin level exceeds 20 mg/dl for chronic HBV with SAE. Consecutive patients with chronic HBV with SAE and a serum bilirubin level of <20 mg/dl who received lamivudine or entecavir were enrolled. Short-term (4 months) survival was evaluated. One hundred fourteen patients received lamivudine, and 53 patients received entecavir. The baseline characteristics were similar for the two groups except that the entecavir group was older and had a lower alanine aminotransferase (ALT) level. Three patients (8.0%) in the entecavir group and 9 patients (7.9%) in the lamivudine group died (P=1.000). If only patients who started antiviral treatment before serum bilirubin level rose to more than 15 mg/dl were included, 3 patients (8.3%) in the entecavir group and 3 patients (3.0%) in the lamivudine group died (P=0.189). If only patients with an HBV DNA level higher than 10(5) copies/ml and a bilirubin level lower than 15 mg/dl were included, 5 out of 40 patients (12.5%) in the entecavir group died and 1 out of 59 patients (1.7%) in the lamivudine group died. Multivariate analysis found that entecavir treatment was associated with more mortality than lamivudine (P=0.035). Early entecavir treatment in patients with high viral load is associated with more short-term mortality than lamivudine for chronic HBV with severe acute exacerbation.

Telbivudine: an upcoming agent for chronic hepatitis B

Telbivudine, the prototype member of beta-L-2 -deoxynucleosides, has proven to be safe in in vitro animal and human studies. Telbivudine given for 4 weeks resulted in an 8-log reduction of woodchuck hepatitis virus DNA, and a 3.8-log reduction of hepatitis B virus DNA in human. After 52 weeks of telbivudine treatment there was an approximate 6-log reduction of hepatitis B virus DNA levels, hepatitis B virus DNA became undetectable by PCR assay in 61% of patients. Its antiviral efficacy is significantly better than lamivudine. The probability of tyrosine-methionine-aspartate-aspartate mutations at 52 weeks of telbivudine therapy is low, although still occurring in 4.5% of patients. After 96 weeks of therapy, the proportion of patients with undetectable hepatitis B virus DNA by PCR assay increased to 71%, but genotypic resistance also increased to 18.2%, with only 4.5% showing alanine aminotransferase flares. Telbivudine is probably one of the most potent antiviral agents for hepatitis B virus that will become available in the near future.

Comparison of the antiviral effects of different nucleos(t)ide analogues in chinese patients with chronic hepatitis B: a head-to-head study

BACKGROUND/AIMS

To assess the antiviral efficacy of lamivudine (LAM), entecavir (ETV), telbivudine (LDT), and lamivudine and adefovir dipivoxil (CLA) combination in previously untreated hepatitis B patients at different time points during a 52-week treatment period.

PATIENTS AND METHODS

A total of 164 patients were included in this prospective, open-label, head-to-head study. Serum levels of alanine transaminase (ALT), hepatitis B virus (HBV) DNA, and hepatitis B e antigen (HBeAg) were measured at baseline, and at 12, 24, and 52 weeks of treatment.

RESULTS

Median reductions in serum HBV DNA levels at 52 weeks (log 10 copies/mL) were as follows: LAM, 3.98; ETV, 3.89; LDT, 4.11; and CLA, 3.36. The corresponding HBV DNA undetectability rates were 83%, 96%, 91%, and 89%, respectively. These two measures showed no significant intergroup differences. Clinical efficacy appeared related to HBV DNA level reduction after 24 weeks of therapy. Patients were divided into three groups based on HBV DNA levels at week 24: Undetectable (<10(3) copies/mL), detectable but <10(4) copies/mL, and >10(4) copies/mL. Patients with levels below quantitation limit (QL) were analyzed at 52 weeks for HBV DNA undetectability rate (94%), ALT normalization rate (83%), and viral breakthrough rate (0%). The corresponding values in the QL-10(4) copies/mL group were 50%, 75%, and 13%, whereas those in the above 10(4) copies/mL group were 53%, 65%, and 18%. There were significant differences at week 52 for HBV DNA levels and viral breakthrough rate between the three groups.

CONCLUSIONS

Different nucleos(t)ide (NUC) analogues tested exhibited no significant differences in effectiveness for Chinese NUC-naive HBV patients during 1-year treatment period.

Baseline prognostic factors and statistic model to predict early virological response in telbivudine-treated patients with chronic hepatitis B

BACKGROUND

Hepatitis B virus (HBV) infection is still a worldwide disease, which may cause liver cirrhosis or even hepatocellular carcinoma. Telbivudine is a potent nucleoside analogue used in the treatment of chronic hepatitis B (CHB); however, drug resistance has remained a challenge. As early virological response can predict long-term efficacy of nucleotide analogue treatment, numerous studies have been conducted in this area.

OBJECTIVES

The aim of this study was to establish baseline prognostic factors and a statistical model to predict early virological response in telbivudine-treated CHB patients.

PATIENTS AND METHODS

One hundred and eight CHB patients without any experience of nucleotide analogue therapy were assigned to receive telbivudine (600 mg, once daily) for at least 24 weeks, and then were followed up every two weeks. Cox proportional hazard regression model analyses were employed to evaluate baseline variables, and further developing a statistical model to predict early virological response.

RESULTS

Negative family history of HBV infection (P = 0.000235), baseline higher serum TBIL (P = 0.038714) and AST (P = 0.020684) concentrations, and lower level of HBV-DNA (P = 0.0034784) were identified to be associated with higher possibility of early virological response. A model was established based on these variables to calculate the risk scores (R) for CHB patients. R > -0.38 suggested early virological response to telbivudine. The model was validated among an independent set of 20 patients.

CONCLUSIONS

Family history as well as baseline bilirubin, AST and HBV DNA levels can predict early virological response. The model provides a better tool for response prediction based on the four prognostic factors.