Long-term monitoring shows hepatitis B virus resistance to entecavir in nucleoside-naïve patients is rare through 5 years of therapy

Association Between Level of Fibrosis, Rather Than Antiviral Regimen, and Outcomes of Patients With Chronic Hepatitis B

BACKGROUND & AIMS

We performed a propensity-score matched analysis to investigate whether entecavir, compared with lamivudine, can reduce risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B after adjusting for level of fibrosis.

METHODS

We performed a retrospective study of 1079 patients with chronic hepatitis B who received first-line therapy with lamivudine (n = 435) or entecavir (n = 644) from 2006 through 2013. Only patients with available liver stiffness value measured by transient elastography were recruited. Liver cirrhosis was diagnosed by ultrasonography. To adjust for the imbalance of patients treated with lamivudine versus entecavir, we performed propensity-score matching (PSM), at a ratio of 1:1, using 7 factors (age, sex, hepatitis B e antigen, alanine aminotransferase, serum albumin, platelet count, and liver stiffness; PSM1) or 8 factors (variables of PSM1 plus ultrasonography measurements of cirrhosis; PSM2). Patients with virologic breakthrough or resistance mutations received rescue therapy.

RESULTS

Over the 7-year period, 91 patients developed HCC and 104 had liver-related events in the entire cohort. In multivariate analyses, level of fibrosis, but not antiviral regimen, was independently associated with risk of HCC (P < .05). The PSM1 group included 342 pairs of patients and the PSM2 group included 338 pairs. Similar proportions of patients given lamivudine versus entecavir developed HCC in each model (10.5% given lamivudine vs 9.9% given entecavir in PSM1 and 11.9% vs 12.6% in PSM2; all P > .05). When PSM was applied to patients with liver stiffness value ≤13 kPa or >13 kPa, patients given lamivudine versus entecavir still had similar cumulative rates of HCC development (all P > .05).

CONCLUSIONS

In a PSM analysis, we associated level of fibrosis, rather than antiviral regimen, with risk of HCC, when patients received appropriate rescue therapy in case of virologic breakthrough or resistance mutations.

Flares during long-term entecavir therapy in chronic hepatitis B

BACKGROUND AND AIM

The incidence and consequences of flares during first-line nucleos(t)ide analogue therapy are largely unknown. We aimed to investigate the incidence and outcome of alanine aminotransferase (ALT) flares during long-term entecavir (ETV) in chronic hepatitis B (CHB).

METHODS

CHB patients treated with ETV monotherapy from 11 European centers were studied. Flare was defined as > 3× increase in ALT compared with baseline or lowest on-treatment level and an absolute ALT > 3× ULN. Flares were designated as host-induced (preceded by hepatitis B virus (HBV)-DNA decline), virus-induced (HBV-DNA increase), or indeterminate (stable HBV-DNA).

RESULTS

Seven hundred and twenty-nine patients were treated with ETV for median of 3.5 years. Thirty patients developed a flare with cumulative incidence of 6.3% at year 5. Baseline hepatitis B e antigen (HBeAg)-positivity (HR 2.84; P = 0.005) and high HBV-DNA (Hazard ratio (HR) 1.30; P = 0.003) predicted flares. There were 12 (40%) host-induced, 7 (23%) virus-induced, and 11 (37%) indeterminate flares. Host-induced flares occurred earlier than virus-induced (median: 15 vs 83 weeks; P = 0.027) or indeterminate flares (15 vs 109 weeks; P = 0.011). Host-induced flares were associated with biochemical remission, and HBeAg (n = 3) and hepatitis B surface antigen (n = 2) seroconversions were exclusively observed among patients with these flares. Virus-induced flares were associated with ETV resistance (n = 2) and non-compliance (n = 1).

CONCLUSION

The incidence of ALT flares during ETV was low in this real-life cohort. ETV can be safely continued in patients with host-induced flares. Treatment adherence and drug resistance must be assessed in patients with virus-induced flares.

Clinical implication of serum Wisteria floribunda agglutinin positive Mac-2-binding protein level on hepatitis B e-antigen loss or seroconversion in hepatitis B e-antigen positive patients

AIM

To examine the impact of pretreatment Wisteria floribunda agglutinin positive Mac-2-binding protein (WFA+ -M2BP) level on hepatitis B e-antigen (HBeAg) loss or HBeAg seroconversion (SC) for patients with nucleoside/nucleotide analog (NUC) therapy naive HBeAg positive chronic hepatitis B (CHB).

METHODS

A total of 57 patients were analyzed. All subjects were initially treated with NUC. We examined the impact of pretreatment WFA+ -M2BP level on HBeAg loss and HBeAg SC using univariate and multivariate analyses.

RESULTS

There were 36 men and 21 women (median age, 39 years). The WFA+ -M2BP cut-off index (COI) level ranged 0.43-12.9 (median, 1.55). WFA+ -M2BP level in patients with F3 or F4 was significantly higher than that with F0-F2. WFA+ -M2BP level in patients with A2 or 3 was significantly higher than that with A0 or 1. For all cases, the 1- and 3-year cumulative HBeAg loss rates were 10.5% and 34.4% and the corresponding cumulative HBeAg SC rates were 8.8% and 29.0%, respectively. In the multivariate analysis, in terms of HBeAg loss, pretreatment HBV DNA of 5 log copies/mL or more and pretreatment WFA+ -M2BP level of more than 1.55 COI tended to be significant factors linked to loss of HBeAg, while in terms of HBeAg SC, pretreatment HBV DNA of 5 log copies/mL or more was an independent predictor and pretreatment WFA+ -M2BP level of more than 1.55 COI tended to be a significant factor.

CONCLUSION

Pretreatment WFA+ -M2BP level may be a useful predictor for HBeAg loss or SC after NUC therapy for patients with HBeAg positive CHB.

Treatment for hepatitis B in patients with drug resistance

Persistent hepatitis B virus (HBV) infections affect about 240 million patients worldwide that are at risk of developing liver cirrhosis or hepatocellular carcinoma. HBV is a small, partially double stranded DNA virus with four overlapping genes and a unique life cycle, which involves the generation of an RNA template for replication via reverse transcription. Mutations occur frequently during chronic infection, and particular selection pressures select distinct mutants. Nucleoside and nucleotide analogues like lamivudine (LMV), entecavir (ETV), telbivudine (LdT), adefovir dipivoxil (ADV) and tenofovir (TDF) are used to achieve long-term suppression of viral replication. Importantly, these drugs have different barriers to resistance, explaining the higher incidence of treatment failure in the past due to drug resistant viral strains for the older compounds LMV, LdT and ADV. On a molecular level, drug resistant mutations usually affect the reverse transcriptase domain of the HBV polymerase protein. Secondary compensatory mutations restore the replication fitness of the mutant virus. From a clinical point of view, patients undergoing antiviral therapy require regular testing for HBV DNA (every 3-6 months). In case of insufficient viral suppression or viral breakthrough (>1 log increase in HBV DNA above nadir), strict adherence to therapy needs to be ensured. If drug resistance is suspected or even molecularly confirmed, rescue therapy strategies exist, usually switching to a noncross-resistant antiviral drug. LMV, LdT and ETV resistant HBV can be treated with TDF monotherapy, ADV resistance with ETV or TDF, and insufficient responses to TDF may require ETV either as mono- or combination therapy. Complex treatment histories with many antivirals may sometimes necessitate the combination of highly effective antivirals like ETV and TDF. Novel treatment targets such as core (capsid) inhibitors, siRNA targeting protein translation, entry inhibitors or immune modulators aim at improving the efficacy of antivirals in order to (functionally) cure hepatitis B.

Efficacy of tenofovir-based rescue therapy in patients with lamivudine-resistant hepatitis B virus: A systematic review and meta-analysis

BACKGROUND

Currently, there are no conclusive results on the efficacy of Tenofovir disoproxil fumarate (TDF) monotherapy in chronic hepatitis B (CHB) patients with lamivudine-resistant (LAM-R).

OBJECTIVE

The aim of this study was to compare the efficacy between TDF and TDF-based combination therapy against LAM-R HBV in CHB patients.

METHODS

Randomized and non-randomized control trials directly comparing TDF and TDF-based therapy for treatment of LAM-R CHB patients, were searched in Pubmed, Medline, EMBASE, database up to June 15, 2015. The data were analyzed with Review Manager (v.5.3).

RESULTS

Five articles (683 patients in total) met entry criteria. The overall efficacy of tenofovir-based combination therapy was not significantly better with regard to the rates of virological response (85.5% vs. 81.5%; RR=0.95, 95%CI=0.88-1.03, P=0.25), ALT normalization (61.9% vs.72.0%; RR=1.18, 95%CI=0.96-1.44, P=0.11) and HBeAg loss (17.0% vs. 18.1%; RR=1.40, 95%CI=0.78-2.49, P=0.26) compared with TDF monotherapy through 48-week treatment. Additionally, subgroup analysis showed that no significant difference was determined as TDF group compared to TDF-based group at 48weeks, in terms of rates of HBV DNA undetectability, ALT normalization and HBeAg loss in the treatment of LAM-R patients with prior failure of LAM monotherapy. Moreover, the rates of HBV DNA suppression between groups were similar through 24 or 48weeks of treatment in LAM-R patients with prior failure of LAM/ADV therapy.

CONCLUSIONS

TDF monotherapy is as effective as TDF-based combination therapy in maintaining viral suppression in LAM-R patients with prior failure of LAM or LAM/ADV therapy.

Entecavir plus tenofovir combination therapy for chronic hepatitis B in patients with previous nucleos(t)ide treatment failure

BACKGROUND AND AIMS

In patients with chronic hepatitis B (CHB) who have failed on other nucleos(t)ide analogs (NUCs), the combination of entecavir (ETV) plus tenofovir disoproxil fumarate (TDF), two potent agents with non-overlapping resistance profiles, may provide a single rescue regimen.

METHODS

In this single-arm, open-label study, 92 CHB patients with a primary non-response, partial response, or virologic breakthrough on their current NUC were switched to ETV (1 mg) plus TDF (300 mg) and treated for 96 weeks.

RESULTS

At baseline, 62 % of patients were HBeAg(+) and mean HBV DNA was 4.4 log10IU/mL. Patients had received ≥1 line of prior NUC therapy, with the latest regimen consisting of monotherapy with ETV (53 %), lamivudine (LVD 22 %), TDF (12 %), adefovir (ADV 4 %), or telbivudine (2 %), or combinations of these agents (7 %); 58 % had evidence of single- or multidrug resistance mutations (LVD 52 %, ETV 26 %; ADV 7 %). Response rates for HBV DNA <50 IU/mL were 76 % (70/92) at week 48 (primary endpoint), and 85 % (78/92) at week 96, including 80 % (16/20) in prior LVD failures, 100 % (4/4) in ADV failures, 82 % (9/11) in TDF failures, and 88 % (42/48) in ETV failures. No treatment-emergent resistance to ETV or ADV was observed. ETV/TDF was well tolerated, with no significant renal or additive toxicities observed.

CONCLUSIONS

In NUC-experienced patients who have failed prior NUC therapy, ETV/TDF was well tolerated and effective, achieving virologic suppression through 96 weeks in the majority (85 %), irrespective of prior NUC exposure, without occurrence of treatment-emergent resistance to either agent.

Comparison of the clinical outcomes between antiviral-naïve patients treated with entecavir and lamivudine-resistant patients receiving adefovir add-on lamivudine combination treatment

BACKGROUND/AIMS

To analyze the effects of preexisting lamivudine (LAM) resistance and applying antiviral treatment (adefovir [ADV] add-on LAM combination treatment) on long-term treatment outcomes, and comparing the clinical outcomes of antiviral-naïve chronic hepatitis B patients receiving entecavir (ETV) monotherapy.

METHODS

This study enrolled 73 antiviral-naïve patients who received 0.5-mg ETV as an initial therapy and 54 patients who received ADV add-on LAM combination treatment as a rescue therapy from July 2006 to July 2010.

RESULTS

During 24-month treatments, the decreases in serum log10HBV-DNA values (copies/mL) were significantly greater in the antiviral-naïve patients treated with ETV than the patients receiving ADV add-on LAM combination treatment. The biochemical response rates for alanine aminotransferase normalization at 6 months (ETV) and 12 months (ADV add-on LAM) were 90.4% (66/73) and 77.8% (42/54), respectively (P=0.048). A Kaplan-Meier analysis indicated that the rates of serologic response, viral breakthrough, and emergence of genotypic resistance did not differ significantly between the two patient groups. There were also no significant intergroup differences in the rates of disease progression (PD) and new development of hepatocellular carcinoma (HCC).

CONCLUSION

The long-term clinical outcomes of antiviral-naïve patients treated with ETV and LAM-resistant patients receiving ADV add-on LAM combination treatment were comparable in terms of the emergence of HCC and disease progression.

Detection of Anti-Hepatitis B Virus Drug Resistance Mutations Based on Multicolor Melting Curve Analysis

Detection of anti-hepatitis B virus (HBV) drug resistance mutations is critical for therapeutic decisions for chronic hepatitis B virus infection. We describe a real-time PCR-based assay using multicolor melting curve analysis (MMCA) that could accurately detect 24 HBV nucleotide mutations at 10 amino acid positions in the reverse transcriptase region of the HBV polymerase gene. The two-reaction assay had a limit of detection of 5 copies per reaction and could detect a minor mutant population (5% of the total population) with the reverse transcriptase M204V amino acid mutation in the presence of the major wild-type population when the overall concentration was 10⁴ copies/μl. The assay could be finished within 3 h, and the cost of materials for each sample was less than $10. Clinical validation studies using three groups of samples from both nucleos(t)ide analog-treated and -untreated patients showed that the results for 99.3% (840/846) of the samples and 99.9% (8,454/8,460) of the amino acids were concordant with those of Sanger sequencing of the PCR amplicon from the HBV reverse transcriptase region (PCR Sanger sequencing). HBV DNA in six samples with mixed infections consisting of minor mutant subpopulations was undetected by the PCR Sanger sequencing method but was detected by MMCA, and the results were confirmed by coamplification at a lower denaturation temperature-PCR Sanger sequencing. Among the treated patients, 48.6% (103/212) harbored viruses that displayed lamivudine monoresistance, adefovir monoresistance, entecavir resistance, or lamivudine and adefovir resistance. Among the untreated patients, the Chinese group had more mutation-containing samples than did the Pakistani group (3.3% versus 0.56%). Because of its accuracy, rapidness, wide-range coverage, and cost-effectiveness, the real-time PCR assay could be a robust tool for the detection if anti-HBV drug resistance mutations in resource-limited countries.

Review article: novel therapies for hepatitis B virus cure - advances and perspectives

BACKGROUND

Current anti-viral therapies, interferon and nucleos(t)ide analogues, have been proven to reduce the progression of chronic hepatitis B (CHB). However, covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) persists, resulting in viral relapse after the discontinuation of treatment.

AIM

To discuss and review novel therapies for chronic hepatitis B infection.

METHODS

Recent published studies which searched from PubMed were comprehensive reviewed. The key words include chronic hepatitis B, hepatitis B virus cure, covalently closed circular DNA, direct acting anti-virals and host targeting agents.

RESULTS

Several novel agents through viral and host targets approaches are under investigations towards functional cure of HBV. On the one hand, direct acting anti-virals targeting virus itself, such as HBV new polymerase inhibitor, entry inhibitor, engineered site-specific nucleases and RNA interference, could inhibit amplification of cccDNA as well as intrahepatic HBV infection and eliminate or silence cccDNA transcription. Inhibitors of HBV nucleocapsid assembly suppress capsid formation and prevent synthesis of HBV DNA. On the other hand, host targeting agents (HTA) include lymphotoxin-β receptor agonist, toll-like receptor agonist, immune checkpoint inhibitors and adenovirus-based therapeutic vaccine. Through enhancing innate and adaptive immune responses, these agents could induce noncytolytic destruction of cccDNA or attack HBV-infected hepatocytes.

CONCLUSION

With these promising approaches, we hope to reach global hepatitis B virus control in the middle of this century.

Entecavir plus tenofovir combination therapy in patients with multidrug-resistant chronic hepatitis B: results of a multicentre, prospective study

BACKGROUND & AIMS

Sequential therapy posed a high risk of emergence of multidrug resistance and presented a management issue in chronic hepatitis B (CHB) treatment. We evaluated the antiviral efficacy and safety of entecavir (ETV) plus tenofovir (TDF) combination therapy in multidrug-resistant (MDR) CHB patients.

METHODS

In this prospective, multicentre study, MDR CHB patients, defined as measurable serum HBV DNA (≥60 IU/ml) while on any rescue treatment regimen for at least 24 weeks and the presence of documented prior genotypic resistance to both nucleoside analogue(s) and nucleotide analogue, were treated with ETV 1.0 mg and TDF 300 mg combination therapy for 48 weeks.

RESULTS

A total of 64 eligible patients who had previously failed to a median three lines of antiviral therapy (range, 2-6) were included. At baseline, median age was 47.0 years, 89.1% were HBeAg(+), and median HBV DNA was 4.24 (range, 2.11-6.73) log10 IU/ml. By week 4, 12, 24 and 48, 15/64 (23.4%), 36/64 (56.3%), 43/64 (67.2%) and 55/64 (85.9%) patients achieved a HBV DNA <60 IU/ml respectively. The mean reduction of HBV DNA from baseline to 4 and 48 weeks was 1.23 log10 IU/ml and 2.38 log10 IU/ml respectively. Although five patients experienced virological breakthrough, all were transient and no resistant mutation to TDF or novel mutation was detected in any patients.

CONCLUSIONS

In difficult-to-treat MDR CHB patients with a high exposure to multiple antiviral drugs, ETV plus TDF combination therapy can provide a very high rate of viral suppression through 48 weeks of treatment.

Prevention and management of hepatitis B virus reactivation in patients with hematological malignancies treated with anticancer therapy

Hepatitis due to hepatitis B virus (HBV) reactivation can be severe and potentially fatal, but is preventable. HBV reactivation is most commonly reported in patients receiving cancer chemotherapy, especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation. All patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc). Patients found to be positive for HBsAg should be given prophylactic antiviral therapy to prevent HBV reactivation. For patients with resolved HBV infection, no standard strategy has yet been established to prevent HBV reactivation. There are usually two options. One is pre-emptive therapy guided by serial HBV DNA monitoring, whereby antiviral therapy is given as soon as HBV DNA becomes detectable. However, there is little evidence regarding the optimal interval and period of monitoring. An alternative approach is prophylactic antiviral therapy, especially for patients receiving high-risk therapy such as rituximab, newer generation of anti-CD20 monoclonal antibody, obinutuzumab or hematopoietic stem cell transplantation. This strategy may effectively prevent HBV reactivation and avoid the inconvenience of repeated HBV DNA monitoring. Entecavir or tenofovir are preferred over lamivudine as prophylactic therapy. Although there is no well-defined guideline on the optimal duration of prophylactic therapy, there is growing evidence to recommend continuing prophylactic antiviral therapy for at least 12 mo after cessation of chemotherapy, and even longer for those who receive rituximab or who had high serum HBV DNA levels before the start of immunosuppressive therapy. Many novel agents have recently become available for the treatment of hematological malignancies, and these agents may be associated with HBV reactivation. Although there is currently limited evidence to guide the optimal preventive measures, we recommend antiviral prophylaxis in HBsAg-positive patients receiving novel treatments, especially the Bruton tyrosine kinase inhibitors and the phosphatidylinositol 3-kinase inhibitors, which are B-cell receptor signaling modulators and reduce proliferation of malignant B-cells. Further studies are needed to clarify the risk of HBV reactivation with these agents and the best prophylactic strategy in the era of targeted therapy for hematological malignancies.

Comparison of entecavir and lamivudine in preventing HBV reactivation in lymphoma patients undergoing chemotherapy: a meta-analysis

Background Multiple studies have compared the efficacy of entecavir with lamivudine in preventing hepatitis B virus (HBV) reactivation among HBV-carrying lymphoma patients with chemotherapy treatment. However, the results were slightly varied. Aim of the review to combine the findings of independent studies assessing the clinical efficacy of the two drugs using a systematic review and meta-analysis. Methods PubMed, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), Chongqing VIP and WanFang Data were retrieved. Two independent reviewers evaluated the study eligibility and extracted eight studies, with 770 patients in total. The meta-analysis was conducted using RevMan 5.3 and STATA software. Results HBV-carrying lymphoma patients receiving lamivudine during chemotherapy had a statistically significantly higher odds of HBV reactivation compared to those receiving entecavir (OR 5.0, 95 % CI 2.85-8.78, P < 0.001). The odds of hepatitis, HBV-Reactivation caused hepatitis and chemotherapy disruption was statistically significantly elevated in the patient group receiving lamivudine compared to the entecavir group (OR 4.12, 95 % CI 1.70-9.98, P = 0.002; OR 11.44, 95 % CI 2.70-48.52, P < 0.001; OR 6.71, 95 % CI 2.34-19.26, P < 0.001, respectively). Furthermore, the HBV reactivation rate in Ann Arbor stages I - II patient group was statistically significantly lower than the one in Ann Arbor stages III-IV group, with an overall pooled value of 0.37 (95 % CI 0.17-0.82, P = 0.01). Conclusion The metaanalysis result suggested that among HBV-carrying lymphoma patients undergoing chemotherapy, entecavir is more effective than lamivudine in preventing HBV reactivation.

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.

Approved Antiviral Drugs over the Past 50 Years

Since the first antiviral drug, idoxuridine, was approved in 1963, 90 antiviral drugs categorized into 13 functional groups have been formally approved for the treatment of the following 9 human infectious diseases: (i) HIV infections (protease inhibitors, integrase inhibitors, entry inhibitors, nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and acyclic nucleoside phosphonate analogues), (ii) hepatitis B virus (HBV) infections (lamivudine, interferons, nucleoside analogues, and acyclic nucleoside phosphonate analogues), (iii) hepatitis C virus (HCV) infections (ribavirin, interferons, NS3/4A protease inhibitors, NS5A inhibitors, and NS5B polymerase inhibitors), (iv) herpesvirus infections (5-substituted 2'-deoxyuridine analogues, entry inhibitors, nucleoside analogues, pyrophosphate analogues, and acyclic guanosine analogues), (v) influenza virus infections (ribavirin, matrix 2 protein inhibitors, RNA polymerase inhibitors, and neuraminidase inhibitors), (vi) human cytomegalovirus infections (acyclic guanosine analogues, acyclic nucleoside phosphonate analogues, pyrophosphate analogues, and oligonucleotides), (vii) varicella-zoster virus infections (acyclic guanosine analogues, nucleoside analogues, 5-substituted 2'-deoxyuridine analogues, and antibodies), (viii) respiratory syncytial virus infections (ribavirin and antibodies), and (ix) external anogenital warts caused by human papillomavirus infections (imiquimod, sinecatechins, and podofilox). Here, we present for the first time a comprehensive overview of antiviral drugs approved over the past 50 years, shedding light on the development of effective antiviral treatments against current and emerging infectious diseases worldwide.

Prediction of virologic response to tenofovir mono-rescue therapy for multidrug resistant chronic hepatitis B

Most guidelines suggest combination therapy including nucleoside and nucleotide analogues for the treatment of chronic hepatitis B (CHB) with multidrug resistance (MD-R). However, long-term combination treatment can evoke high costs and safety problems. Therefore, we investigated the efficacy of tenofovir disoproxil fumarate (TDF) mono-rescue therapy for viral suppression in patients with CHB exhibiting MD-R. We reviewed patients with CHB exhibiting antiviral drug resistance treated by TDF mono-rescue therapy from December 2012 to June 2014. The patients were categorized into three groups: lamivudine-resistance (LAM-R) group (n = 290), and LAM-R + adefovir-resistance (ADV-R) group (n = 43), and LAM-R + entecavir-resistance (ETV-R) group (n = 113). We compared the virologic response rate according to the multiplicity of resistance and investigated the predictive factors of a virologic response. For a median of 15 months (range, 6-24 months) of TDF mono-rescue therapy, the cumulative virologic response rates were 82.8, 81.4, and 84.1% in the LAM-R, LAM-R + ADV-R, and LAM-R + ETV-R groups, respectively (P = 0.239). Multivariate analysis revealed that multiplicity of resistance did not influence the achievement of a virologic response (P = 0.218). However, the baseline HBV DNA level significantly influenced the achievement of a virologic response for the treatment of CHB with MD-R (P < 0.001). TDF mono-rescue therapy is an appropriate treatment for CHB with MD-R, and the baseline HBV DNA level is a significant predictive factor for a virologic response. These factors should be considered before treating CHB with MD-R.

Tenofovir monotherapy versus tenofovir and entecavir combination therapy in patients with entecavir-resistant chronic hepatitis B with multiple drug failure: results of a randomised trial

OBJECTIVE

Little clinical data are available regarding the optimal treatment of patients who harbour entecavir (ETV)-resistant HBV.

DESIGN

In this multicentre randomised trial, patients who had HBV with ETV resistance-associated mutations and serum HBV DNA concentrations >60 IU/mL were randomised to receive tenofovir disoproxil fumarate (TDF, 300 mg/day) monotherapy (n=45) or TDF and ETV (1 mg/day) combination therapy (n=45) for 48 weeks.

RESULTS

Baseline characteristics were comparable between groups, including HBV DNA levels (median, 4.02 log10 IU/mL) and hepatitis B e antigen-positivity (89%). All patients had at least one ETV-resistance mutation: rtT184A/C/F/G/I/L/S (n=49), rtS202G (n=43) and rtM250L/V (n=7), in addition to rtM204V/I (n=90). All except one patient in the TDF group completed 48 weeks of treatment. At week 48, the proportion of patients with HBV DNA <15 IU/mL, the primary efficacy endpoint, was not significantly different between the TDF and TDF+ETV groups (71% vs. 73%; p>0.99). The mean change in HBV DNA levels from baseline was not significantly different between groups (-3.66 vs. -3.74 log10 IU/mL; p=0.81). Virological breakthrough occurred in one patient on TDF, which was attributed to poor drug adherence. At week 48, six and three patients in the TDF and TDF+ETV groups, respectively, retained their baseline resistance mutations (p>0.99). None developed additional resistance mutations. Safety profiles were comparable in the two groups.

CONCLUSIONS

TDF monotherapy for 48 weeks provided a virological response comparable to that of TDF and ETV combination therapy in patients infected with ETV-resistant HBV.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID NCT01639092.

Efficacy of telbivudine with conditional tenofovir intensification in patients with chronic hepatitis B: results from the 2-year roadmap strategy

BACKGROUND

A 2-year roadmap study was conducted to evaluate the efficacy and safety of tenofovir intensification at Week 24 in patients with chronic hepatitis B (CHB) receiving telbivudine.

SCOPE

A prospective multicenter study was conducted in treatment-naive patients with hepatitis B e antigen (HBeAg)-positive CHB. All patients received telbivudine (600 mg/day) until Week 24. Thereafter, patients with detectable hepatitis B virus (HBV) DNA (≥300 copies/mL) were administered tenofovir (300 mg/day) plus telbivudine, and patients with undetectable HBV DNA continued telbivudine monotherapy until Week 104. The primary endpoint was the proportion of patients with undetectable HBV DNA (<300 copies/mL) at Weeks 52 and 104.

FINDINGS

A total of 105 patients were enrolled in the trial, of which 100 were eligible for efficacy analysis. Undetectable HBV DNA levels were observed at Week 24 in 55 patients who continued on with telbivudine monotherapy. The remaining 45 patients with detectable HBV DNA received tenofovir add-on therapy. With monotherapy, 100% (55/55) and 94.5% (52/55) of patients achieved HBV DNA <300 copies/mL at Weeks 52 and 104, respectively; the corresponding values for patients with add-on therapy were 84.4% (38/45) and 93.3% (42/45). Overall, undetectable HBV DNA (<300 copies/mL) was found in 93% (93/100) and 94% (94/100) of patients at Weeks 52 and 104, respectively. HBeAg seroconversion rate was 44.4% (44/99) at Week 104 for the overall patient population. One patient in the monotherapy group and six in the intensification group demonstrated HBsAg clearance at Week 104. HBsAg seroconversion was observed in four patients at Week 104, all belonged to the tenofovir intensification group. Eight patients sustained HBsAg loss during a posttreatment follow-up period of 16 weeks. Alanine aminotransferase (ALT) normalization was constant in the telbivudine monotherapy group, whereas a progressive improvement was observed in the tenofovir intensification group. Two patients in the monotherapy and none in the intensification group experienced viral breakthrough by Week 104. There were no reports of myopathy in either group. The mean changes in estimated glomerular filtration rate (eGFR), estimated using the Modification of Diet in Renal Disease (MDRD) formula, from baseline to Week 104 were +6.145 mL/min/1.73 m(2) (p=0.0230) and +7.954 mL/min/1.73 m(2) (p=0.0154) in the telbivudine monotherapy and tenofovir intensification groups, respectively. The incidence of serious AEs was four in the telbivudine monotherapy and two in the tenofovir intensification group. The main limitation of this study was limited sample size, which made the power of the observation low, and the absence of a comparative subgroup to assess the progression of patients with detectable HBV DNA without treatment intensification.

CONCLUSIONS

Data from this 2-year roadmap study confirmed that telbivudine with add-on tenofovir was effective and well tolerated in patients with CHB. Telbivudine was associated with an improvement in eGFR from baseline in both the groups.

Hepatitis B: Working Towards a Cure

First-line oral therapies for hepatitis B are effective at viral suppression, and treatment can lead to biochemical improvement and histologic regression. Unfortunately, recommended endpoints of treatment such as HBeAg loss and seroconversion may not be durable, with high rates of seroreversion, requiring monitoring, and unfortunately, low rates of  HBsAg loss/seroconversion. Additionally, meeting these endpoints requires years or even indefinite administration, leading to concerns regarding cost, side effects, and high rates of nonadherence. This article will review defined endpoints of therapy and their durability, the risks of long-term therapy, and the evolving new therapies aimed at a viral cure.

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.

Alternative Therapies for Chronic Hepatitis B Patients With Partial Virological Response to Standard Entecavir Monotherapy

BACKGROUND

Entecavir (ETV) is a first-line, oral antinucleoside agent for the treatment of chronic hepatitis B patients. Despite its high potency, some patients may still be viremic after prolonged therapy with ETV monotherapy. Long-term outcome data comparing maintained ETV monotherapy to alternative therapies in persistently viremic patients are limited. Our goal was to compare complete viral suppression (CVS) rates [hepatitis B DNA (HBV DNA)<40 to 60 IU/mL] with alternative therapies to continued ETV monotherapy in ETV partial responders.

METHODS

This is a retrospective cohort study consisting of 86 consecutive treatment-naive, ETV=0.5 mg partial responders (detectable HBV DNA after ≥12 mo on ETV) who maintained ETV=0.5 mg daily (n=29) or switched to either ETV=1.0 mg daily (n=32) or ETV/tenofovir (TDF)=0.5 mg/300 mg (n=25) in 3 US GI/liver clinics from January 2005 to January 2012. Patients were identified by International Classification of Diseases, Ninth Revision query and data were collected by individual chart review. For those who remained on ETV=0.5 mg, comparison at regimen "switch time" was done using values at 12 months from initial ETV therapy. Rates of CVS were evaluated using Kaplan-Meier methods. Multivariate Cox proportional hazard models were used to estimate hazard ratio (HR) relating to potential predictors to the desirable outcomes of CVS.

RESULTS

In all therapy groups, the majority of patients were Asian (93.1% to 100.0%), male (64.0% to 68.8%), and hepatitis B e antigen-positive (95.8% to 100.0%) and had similar baseline alanine aminotransferase (ALT) levels. However, baseline HBV DNA (7.0 vs. 7.9 vs. 7.8 log10 IU/mL, P=0.05) and HBV DNA at regimen switch point (2.9 vs. 3.7 vs. 3.6 log10 IU/mL, P=0.0014) were lower in the ETV=0.5 mg cohort compared with those switched to ETV=1.0 mg or ETV/TDF, respectively. The ETV=0.5 mg cohort also had the shortest duration of ETV=0.5 mg therapy before switch (11.8 vs. 13.5 vs. 19.2 mo, P<0.0001). After the switch point, more patients on ETV/TDF achieved CVS compared with those on ETV=0.5 mg or ETV=1.0 mg at month 6 (77.3% vs. 13.8% vs. 9.4%), month 12 (86.4% vs. 40.5% vs. 25.0%), and month 18 (100% vs. 70.2% vs. 33.3%). Compared with the ETV=0.5 mg and ETV=1.0 mg groups, the ETV/TDF group also had higher rates of ALT normalization at month 6 (73.0% vs, 46.4% vs. 63.0%), month 12 (79.7% vs. 69.5% vs. 77.9%), and month 18 (100.0% vs. 69.5% vs. 86.8%), respectively. The multivariate analyses, inclusive of baseline age and treatment duration on initial therapy with ETV=0.5 mg, indicated that the ETV/TDF combination (HR=12.19, P<0.0001) was independently and positively associated with CVS, whereas high HBV DNA levels at baseline (HR=0.77, P=0.02) and at switch point (HR=0.46, P=0.002) were negatively associated with CVS. ETV=1.0 mg dose was not a predictor for CVS compared with ETV=0.5 mg.

CONCLUSIONS

Following adjustments for HBV DNA levels and prior treatment duration, ETV/TDF combination therapy independently predicted superior viral suppression and ALT normalization in partial responders to ETV=0.5 mg daily compared with ETV=0.5 mg or ETV=1.0 mg monotherapy. In patients who continued to be viremic after 12 months of ETV=0.5 mg, one third were still viremic after another 18 months on the same therapy. Alternative therapies should be considered for these patients.

The suppressive effect of nucleos(t)ide analogue treatment on the incidence of hepatocellular carcinoma in chronic hepatitis B patients

The development of nucleos(t)ide analogues (NA) has influenced hepatitis B virus management. However, the annual incidence rate during NA treatment has been reported to be 0.3-1.2% in non-cirrhosis cases and 1.8-6.0% in cirrhosis cases, indicating that the suppressive effect of NA treatment on hepatocellular carcinoma (HCC) would be insufficient. Past studies, including one randomized control trial that compared lamivudine treatment with placebo, have revealed that NA treatment could suppress the incidence of HCC in patients with advanced fibrosis. However, it remains unknown whether NA treatment can suppress the incidence of HCC in chronic hepatitis patients without advanced fibrosis. The HCC incidence in patients treated with entecavir was similar to that of those treated with lamivudine, although entecavir exhibits a stronger viral suppression than lamivudine. The following risk factors related to the incidence of HCC during NA treatment have been identified: older age, male gender, pre-existing cirrhosis, a family clustering of hepatitis B virus, lower platelet counts, and higher hepatitis B core-related antigens as baseline factors and higher alpha fetoprotein levels as an on-treatment factor. Conversely, the loss of the hepatitis B surface antigen (HBsAg) by interferon or NA was correlated with a lower HCC incidence rate. Because interferon treatment has much more effects on reducing HBsAg levels compared with NA treatment, a combination treatment with NA and pegylated interferon can bring additional reduction of HBsAg levels compared with NA monotherapy. Further study is needed to clarify this.

A comparison of telbivudine and entecavir in the treatment of hepatitis B e antigen-positive patients: a prospective cohort study in China

There are few studies directly comparing the efficacy and safety of telbivudine and entecavir. The present prospective cohort study aimed to evaluate the long-term efficacy and safety of these compounds in 196 hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B for a median follow-up period of 172 weeks; 97 were treated with telbivudine and 99 were treated with entecavir. Patients showing suboptimal responses could also take adefovir at 24-48 weeks and all patients with viral breakthrough were started on adefovir. The 240-week cumulative proportions of patients showing undetectable hepatitis B DNA levels and serum alanine transaminase (ALT) normalization were similar in the two study groups. Viral breakthrough developed in 14% of the telbivudine group and in 2% of the entecavir group (p 0.002). Interestingly, the cumulative proportions of patients treated with entecavir and telbivudine showing HBeAg seroconversion were 12% versus 21% at 48 weeks (p 0.041), 15% versus 38% at 96 weeks (p 0.001), 24% versus 50% at 144 weeks (p 0.001), 33% versus 53% at 192 weeks (p 0.004) and 36% versus 53% at 240 weeks (p 0.005), respectively. Patients treated with telbivudine were therefore significantly more likely to show HBeAg seroconversion than those receiving entecavir and similar results were observed in study sub-groups matched for age, serum ALT, and HBV DNA levels. A safety analysis identified no differences between grade 3/4 creatine kinase elevations in the study groups and only telbivudine was associated with improved kidney function.

A review of supportive care and recommended preventive approaches for patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most prevalent type of adult leukemia encountered in the western world. Patients with CLL are typically older, with a median age in the 70s, and are at risk for certain complications due to the disease itself and due to the therapies imparted for this. Patients with CLL are at a higher risk of infections, partly due to disease and partly due to the immune dysfunction induced by treatment, such as purine analogous-based chemoimmunotherapy, which leads to lymphocyte depletion. Infections are a leading cause of complications and death in CLL patients. Also, CLL patients have been shown to have a higher incidence of other malignancies. Despite this knowledge, there are no definite guidelines as to what is the best approach to manage or prevent these associated complications of CLL. In this review, the authors discuss the data available and outline recommendations as to the best way to approach this issue in daily practice.

Treatment Outcomes With First-line Therapies With Entecavir and Tenofovir in Treatment-Naive Chronic Hepatitis B Patients in a Routine Clinical Practice

BACKGROUND

Given their high efficacy, entecavir (ETV) and tenofovir (TDF), are the recommended first-line therapies for chronic hepatitis B, but it is not clear whether the efficacy reported from pivotal trials is similar to the outcomes seen in routine practice.

GOALS

Our goal was to examine the treatment outcomes of antiviral therapy in such setting.

PATIENTS AND METHODS

We conducted a retrospective study of 557 consecutive treatment-naive patients who started either ETV (n=443) or TDF (n=114) at 3 US liver clinics between January 2005 and 2012. Primary study endpoint was complete viral suppression (CVS) rate (hepatitis B virus DNA<40 IU/mL).

RESULTS

The majority of patients in both ETV and TDF groups were Asians, hepatitis B e antigen (HBeAg) negative, male, and with similar pretreatment alanine aminotransferase and hepatitis B virus DNA levels. Similar proportions of patients in the ETV and TDF groups achieved CVS at 24 months: 87.7% versus 87.0%, respectively. Cumulative rates of virological breakthrough in the ETV and TDF groups were 1.0% versus 4.8% (P=0.26) and 3.7% versus 9.8% (P=0.04) at month 12 and 24, respectively; and all were associated with medication nonadherence. Cumulative rate of medication nonadherence was lower in the ETV than TDF group: 4.6% versus 7.8% at month 12 and 8.9% versus 16.9% at month 24, respectively.

CONCLUSIONS

Patients treated with either ETV or TDF achieve a similar rate of CVS at 24 months. The primary contributor to suboptimal response was medication nonadherence. Attention to medication adherence is needed in a routine clinical setting.

Randomized, controlled trial of entecavir versus placebo in children with hepatitis B envelope antigen-positive chronic hepatitis B

This ongoing, randomized phase III study assesses the safety and efficacy of entecavir versus placebo in nucleos(t)ide-naïve children (2 to <18 years) with hepatitis B envelope antigen (HBeAg)-positive chronic hepatitis B (CHB). Blinded treatment was administered for a minimum of 48 weeks. After week 48, patients with HBeAg seroconversion continued blinded treatment; those without switched to open-label entecavir. The primary endpoint was HBeAg seroconversion and HBV DNA <50 IU/mL at week 48. A total of 180 patients were randomized (2:1) and treated. Baseline median age was 12 years, with approximately 50% of children ages >12 to <18, and 25% each ages ≥2 to ≤6 and >6 to ≤12. Rates for the primary endpoint at week 48 were significantly higher with entecavir than placebo (24.2% [29 of 120] vs. 3.3% [2 of 60]; P = 0.0008). Furthermore, higher response rates were observed with entecavir compared with placebo for the key week 48 secondary endpoints: HBV DNA <50 IU/mL (49.2% [59 of 120] vs. 3.3% [2 of 60]; P < 0.0001); alanine aminotransferase normalization (67.5% [81 of 120] vs. 23.3% [14 of 60]; P < 0.0001); and HBeAg seroconversion (24.2% [29 of 120] vs. 10.0% [6 of 60]; P = 0.0210). Among entecavir-randomized patients, there was an increase in all efficacy endpoints between weeks 48 and 96, including an increase from 49% to 64% in virological suppression. The cumulative probability of emergent entecavir resistance through years 1 and 2 of entecavir was 0.6% and 2.6%, respectively. Entecavir was well tolerated with no observed differences in adverse events or changes in growth compared with placebo.

CONCLUSION

In childhood CHB, entecavir demonstrated superior antiviral efficacy to placebo with a favorable safety profile. These results support the use of entecavir as a therapeutic option in children and adolescents with CHB.

Genetic Evidence for Genotoxic Effect of Entecavir, an Anti-Hepatitis B Virus Nucleotide Analog

Nucleoside analogues (NAs) have been the most frequently used treatment option for chronic hepatitis B patients. However, they may have genotoxic potentials due to their interference with nucleic acid metabolism. Entecavir, a deoxyguanosine analog, is one of the most widely used oral antiviral NAs against hepatitis B virus. It has reported that entecavir gave positive responses in both genotoxicity and carcinogenicity assays. However the genotoxic mechanism of entecavir remains elusive. To evaluate the genotoxic mechanisms, we analyzed the effect of entecavir on a panel of chicken DT40 B-lymphocyte isogenic mutant cell line deficient in DNA repair and damage tolerance pathways. Our results showed that Parp1-/- mutant cells defective in single-strand break (SSB) repair were the most sensitive to entecavir. Brca1-/-, Ubc13-/- and translesion-DNA-synthesis deficient cells including Rad18-/- and Rev3-/- were hypersensitive to entecavir. XPA-/- mutant deficient in nucleotide excision repair was also slightly sensitive to entecavir. γ-H2AX foci forming assay confirmed the existence of DNA damage by entecavir in Parp1-/-, Rad18-/- and Brca1-/- mutants. Karyotype assay further showed entecavir-induced chromosomal aberrations, especially the chromosome gaps in Parp1-/-, Brca1-/-, Rad18-/- and Rev3-/- cells when compared with wild-type cells. These genetic comprehensive studies clearly identified the genotoxic potentials of entecavir and suggested that SSB and postreplication repair pathways may suppress entecavir-induced genotoxicity.

New therapeutic agents for chronic hepatitis B

The treatment goal for chronic hepatitis B is true eradication of the hepatitis B virus, but this is rarely achieved with first-line treatment regimens because of an inability to disrupt covalently closed circular DNA and an inadequate host immune response. Therefore, new antiviral agents are needed to target various stages of the hepatitis B virus lifecycle and modulation of the immune system. This Review provides a summary of available regimens with their strengths and limitations, and highlights future therapeutic strategies to target the virus and host immune response. These new agents can hopefully lead to a finite duration of treatment, and provide a functional and durable cure for chronic hepatitis B infection.

Efficacy of Tenofovir-Based Combination Therapy versus Tenofovir Monotherapy in Chronic Hepatitis B Patients Presenting with Suboptimal Responses to Pretreatment: A Meta-Analysis

Background/Aims. It remains unclear whether tenofovir disoproxil fumarate- (TDF-) based combination therapy produces better outcomes than TDF monotherapy in chronic hepatitis B (CHB) patients. The aim of this study was to compare the efficacy of the two regimens by performing a meta-analysis. Methods. A comprehensive literature search was performed on the comparison of TDF-based combination therapy and monotherapy for CHB patients in the PubMed, Embase, Web of Science, and the Cochrane Libraries. Both dichotomous and continuous variables were extracted and pooled outcomes were expressed as risk ratio (RR) or standard mean difference (SMD). Results. Nine eligible studies (1089 subjects in total) were included in our analysis. The proportion of patients with undetectable HBV DNA at 24, 48, and 96 weeks were similar between the two comparable groups (62.5% versus 70.9%, P = 0.086; 78.1% versus 83.7%, P = 0.118; 86.4% versus 87.9%, P = 0.626, resp.). HBV DNA reduction, rates of ALT normalization, hepatitis B e antigen (HBeAg) loss, and HBeAg seroconversion were also similar between the two groups. Conclusions. On the current data, TDF-based combination therapy seemed to be no better than those achieved by monotherapy. Further studies are needed to verify this comparison.

Metabonomic window into hepatitis B virus-related hepatic diseases

Metabonomics has recently been widely used to discover the pathogenesis and find potential metabolic markers with high sensitivity and specificity. Furthermore, it develops new diagnosis and treatment methods, increases early phase diagnosis rates of certain diseases and provides a new basis for targeted therapy. This review mainly analyzes the research progress of the metabonomics of hepatitis B virus (HBV)-related hepatic diseases, hoping to discover some potential metabolic markers for identification of HBV-related hepatic diseases from other etiologies and for HBV-related hepatitis, liver cirrhosis and hepatocellular carcinoma. This can contribute to early discovery, diagnosis and treatment, eventually increasing the survival rate of HBV-related hepatic diseases.

Overview of hepatitis B virus mutations and their implications in the management of infection

Hepatitis B virus (HBV) affects approximately two billion people worldwide and more than 240 million people in the world are currently chronic carrier that could develop serious complications in the future, like liver cirrhosis and hepatocellular carcinoma. Although an extended HBV immunization program is being carried out since the early ‘80s, representing effective preventive measure, leading to a dramatic reduction of HBV hepatitis incidence, globally HBV infection still represents a major public health problem. The HBV virus is a DNA virus belongs to the Hepadnaviridae family. The HBV-DNA is a circular, partial double strand genome. All coding information is on the minus DNA strand and it is organized into four open reading frames. Despite hepatitis B virus is a DNA virus, it has a high mutation rate due to its replicative strategy, that leads to the production of many non-identical variants at each cycle of replication. In fact, it contains a polymerase without the proofreading activity, and uses an RNA intermediate (pgRNA) during its replication, so error frequencies are comparable to those seen in retroviruses and other RNA viruses rather than in more stable DNA viruses. Due to the low fidelity of the polymerase, the high replication rate and the overlapping reading frames, mutations occur throughout the genome and they have been identified both in the structural and not structural gene. The arise of mutations being to develop of a whole of viral variants called “quasi-species” and the prevalent population, which favors virus replication, was selected by viral fitness, host’s immune pressure and external pressure, i.e., vaccination or antiviral therapy. Naturally occurring mutations were found both in acute and chronic subjects. In the present review we examine and discuss the most recent available data about HBV genetic variability and its significance.

Prophylactic managements of hepatitis B viral infection in liver transplantation

Liver transplantation (LT) is a considerably effective treatment for patients with end-stage hepatitis B virus (HBV)-related liver disease. However, HBV infection often recurs after LT without prophylaxis. Since the 1990s, the treatment for preventing HBV reinfection after LT has greatly progressed with the introduction of hepatitis B immunoglobulin (HBIG) and nucleos(t)ide analogues (NAs), resulting in improved patient survival. The combination therapy consisting of high-dose HBIG and lamivudine is highly efficacious for preventing the recurrence of HBV infection after LT and became the standard prophylaxis for HBV recurrence. However, mainly due to the high cost of HBIG treatment, an alternative protocol for reducing the dose and duration of HBIG has been evaluated. Currently, combination therapy using low-dose HBIG and NAs is considered as the most efficacious and cost-effective prophylaxis for post-LT HBV reinfection. Recently, NA monotherapy and withdrawal of HBIG from combination therapy, along with the development of new, potent high genetic barrier NAs, have provided promising efficacy, especially for low-risk recipients. This review summarizes the prophylactic protocol and their efficacy including prophylaxis of de novo HBV infection from anti-HBc antibody-positive donors. In addition, challenging approaches such as discontinuation of all prophylaxis and active immunity through hepatitis B vaccination are discussed.

Prevention and management of hepatitis B virus reactivation in cancer patients

Hepatitis B virus (HBV) reactivation during immunosuppressive therapy is common in patients with solid tumor or hematological malignancies. It is associated with significant morbidity and mortality due to hepatitis flare and/or hepatic decompensation. These consequences arising from HBV reactivation are, however, largely preventable. Routine screening for HBV serologic status is recommended for all cancer patients undergoing chemotherapy or biologics. By recognizing different serological patterns (which represent either overt or occult HBV infection) and the types of immunosuppressive therapies prescribed, a risk-adapted approach can be established. Prophylactic therapy with nucleos(t)ide analogues (prior to or concomitantly with the commencement of immunosuppressive therapies) is more effective than pre-emptive therapy (starting antiviral when HBV DNA level is rising) in high-risk individuals. Entecavir has been proven to be more effective than lamivudine according to recent studies. Close monitoring of serum HBV level is the preferred strategy in low-risk patients. However, the optimal interval of DNA monitoring and the duration of therapy remain unknown.

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.

Off-treatment efficacy of 3-year nucleos(t)ide analogues in chronic hepatitis B patients

Lamivudine, telbivudine, and entecavir are the first-line drugs covered by the Taiwan National Health Insurance as 3-year treatments for patients with chronic hepatitis B virus (HBV), but the optimal treatment duration of each remains unclear. We aimed to detect HBV treatment-cessation durability, and compare the predictors in patients with and without clinical relapse. In this retrospective cohort study, 210 patients with chronic HBV who tested hepatitis B e-antigen positive or hepatitis B e-antigen negative were treated for 3 years with a nucleos(t)ide analogue. Of these, 102 patients continued therapy after 3 years, while 88 patients stopped treatment and were followed for 1 year due to financial difficulties. Efficacy was assessed in terms of alanine aminotransferase (ALT) level normalization, HBV DNA clearance, virus breakthrough, clinical relapse, and liver decompensation. The durability predictors were evaluated by host factors, HBV DNA, and drug differences. Eighty patients (14 on lamivudine, 19 on telbivudine, and 47 on entecavir) were recruited. There was no difference in clinical-relapse rate among lamivudine, telbivudine, and entecavir (35.7% vs. 36.8% vs. 31.9%, respectively; p = 0.916), and liver decompensated hepatitis was absent. In baseline clinical characteristics, there were no differences between the clinical-relapse and nonrelapse groups in age, sex, cirrhosis, prior treatment, HBV DNA, pretreatment ALT, or hepatitis B e-antigen (HBeAg). The mean 3(rd) year serum ALT level differed significantly between clinical-relapse and nonrelapse patients (37.5 U/L vs. 27.7 U/L, respectively; p = 0.044). The 3-year nucleos(t)ide analogue off-treatment in patients with chronic HBV delivered according to the Taiwan National Health Insurance guidelines had an overall 33.8% 1-year clinical-relapse rate without any decompensated hepatitis flare-ups.

Design and synthesis of pyridine-pyrazole-sulfonate derivatives as potential anti-HBV agents

Hepatitis B virus (HBV) is an infectious disease, which can cause acute and chronic infections.

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.

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.

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.

Antiviral therapy in chronic hepatitis B viral infection during pregnancy: A systematic review and meta-analysis

Perinatal or mother-to-child transmission (MTCT) of hepatitis B virus (HBV) remains the major risk factor for chronic HBV infection worldwide. In addition to hepatitis B immune globulin and vaccination, oral antiviral therapies in highly viremic mothers can further decrease MTCT of HBV. We conducted a systematic review and meta-analysis to synthesize the evidence on the efficacy and maternal and fetal safety of antiviral therapy during pregnancy. A protocol was developed by the American Association for the Study of Liver Diseases guideline writing committee. We searched multiple databases for controlled studies that enrolled pregnant women with chronic HBV infection treated with antiviral therapy. Outcomes of interest were reduction of MTCT and adverse outcomes to mothers and newborns. Study selection and data extraction were done by pairs of independent reviewers. We included 26 studies that enrolled 3622 pregnant women. Antiviral therapy reduced MTCT, as defined by infant hepatitis B surface antigen seropositivity (risk ratio = 0.3, 95% confidence interval 0.2-0.4) or infant HBV DNA seropositivity (risk ratio = 0.3, 95% confidence interval 0.2-0.5) at 6-12 months. No significant differences were found in the congenital malformation rate, prematurity rate, and Apgar scores. Compared to control, lamivudine or telbivudine improved maternal HBV DNA suppression at delivery and during 4-8 weeks' postpartum follow-up. Tenofovir showed improvement in HBV DNA suppression at delivery. No significant differences were found in postpartum hemorrhage, cesarean section, and elevated creatinine kinase rates.

CONCLUSIONS

Antiviral therapy improves HBV suppression and reduces MTCT in women with chronic HBV infection with high viral load compared to the use of hepatitis B immunoglobulin and vaccination alone; the use of telbivudine, lamivudine, and tenofovir appears to be safe in pregnancy with no increased adverse maternal or fetal outcome.

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.

Hepatitis B: 50 years after the discovery of Australia antigen

It is an honour to be invited to recount the progress in our understanding and management of hepatitis B 50 years after the discovery of Australia antigen (Au Ag). During this half century, we have gone from identifying the causative agent--hepatitis B virus (HBV), understanding its biology and the disease it causes, to having vaccines that can prevent HBV infection and antiviral therapy that can suppress HBV replication and prevent progression of HBV-related liver disease. As a result of the progress, prevalence of HBV infection and morbidity and mortality from chronic HBV infection has declined.

Cost-effectiveness analysis of oral anti-viral drugs used for treatment of chronic hepatitis B in Turkey

BACKGROUND

All international guidelines suggested that Tenofovir and Entecavir are the primary drugs at the first line therapy for the treatment of chronic hepatitis B (CHB). However, in Turkey these medications reimbursed at the second line therapy according to the Healthcare Implementation Notification. The aim of this study is to compare the cost effectiveness of oral antiviral treatment strategies in CHB for Turkey using lamuvidine, telbuvidine, entecavir, and tenofovir as medications.

METHODS

The analysis was conducted using Markov models. The analysis scenarios based on first line treatment options with Lamuvidine, Telbuvidine, Entecavir, and Tenofovir as the medications. In the analysis, inadequate response or resistance after receiving 12 months of the treatment with Entecavir and Telbivudine were compared to the results found from switching from Entecavir to Tenofovir or from switching from Telbuvidine to Tenofovir. In additional, inadequate response or resistance after receiving 6 months of the treatment for Lamivudine was compared to the results found from switching from Lamivudine to Tenofovir. The study population included men and women, who were 40 years of age. The patients` compliance was estimated 100 % for all of the therapy options. The model duration was constructed to evaluate, treatment strategy duration of 40 years. The cost of medications, examinations/follow-ups and complications were included in the model. Years of Potential Life Lost was used as the health outcome. An incremental cost-effectiveness ratio analysis has been conducted.

RESULTS AND DISCUSSION

While the minimum years of life lost was found as 0.22 with tenofovir treatment in 5 years, treatment cost was calculated as 12,169 TL. These values were detected as 0.56 years and 7727 TL, 0.37 years and 12,770 TL, respectively for lamuvidine and telbuvidine treatments. The maximum years of life lost and treatment cost was with lamuvidine treatment were detected as 1.60 years and 18,813 TL and, secondly 0.89 years and 24,007 TL for lamuvidine-tenofovir treatment during 10 years. The minimum years of life lost and cost are 0.54 year and 35,821 TL for tenofovir treatment during 10 years. The minimum years of life lost and cost were determined as 1.21 years and 52,839 TL for tenofovir treatment strategy during 20 years. During 30 years period, tenofovir treatment was found to have the minimum years of life lost (1.73 years) and minimum cost (84,149 TL). When the results of 40 years period were analyzed, years of life lost and costs are 2.06 years and 119,604 TL, 2.13 years and 162,115 TL, 2.13 years and 161,642 TL, 6.52 years and 147,245 TL, 3.20 years and 132,157 TL, 4.10 years and 151,059 TL and 3.05 years and 138,182 TL for tenofovir, entecavir, entecavir-tenofovir, lamuvidine, lamuvidine-tenofovir, telbivudine and telbivudine-tenofovir.

CONCLUSIONS

In the model presented in this study, in cost effectiveness analysis about CHB treatments, Tenofovir was found to be one of the cost effective methods in comparison with other treatment strategies different time intervals. Beyond this achievement Tenofovir has shown to reduce cumulative treatment cost in first line CHB treatment when compared with regard to 40 year cumulative treatment cost.