Prior exposure to lamivudine increases entecavir resistance risk in chronic hepatitis B Patients without detectable lamivudine resistance. Antimicrob Agents Chemother. 2014;58:1730-1737. [PMID: 24395227 DOI: 10.1128/aac.02483-13]

Novel Therapies of Hepatitis B and D

Hepatitis B virus (HBV) infection is a global public health issue and is a major cause of cirrhosis and hepatocellular carcinoma (HCC). Hepatitis D virus (HDV) requires the hepatitis B surface antigen (HBsAg) to replicate. The eradication of HBV, therefore, can also cure HDV. The current therapies for chronic hepatitis B and D are suboptimal and cannot definitely cure the viruses. In order to achieve functional or complete cure of these infections, novel therapeutic agents that target the various sites of the viral replicative cycle are necessary. Furthermore, novel immunomodulatory agents are also essential to achieve viral clearance. Many of these new promising compounds such as entry inhibitors, covalently closed circular DNA (cccDNA) inhibitors, small interfering RNAs (siRNAs), capsid assembly modulators and nucleic acid polymers are in various stages of clinical developments. In this review article, we provided a comprehensive overview of the structure and lifecycle of HBV, the limitations of the current therapies and a summary of the novel therapeutic agents for both HDV and HBV infection.

Nucleos(t)ide Analogues for Reducing Hepatocellular Carcinoma in Chronic Hepatitis B Patients: A Systematic Review and Meta-Analysis

Background/Aims

Studies have shown that nucleos(t)ide analogue (NA) treatment can reduce the risk of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients, but it is unclear which NA is most effective. We performed a meta-analysis and systematic review comparing the efficacies of NAs in CHB patients.

Methods

We searched literature databases for randomized controlled trials (RCTs) and observational studies that analyzed the hepatic biochemical response, virological response, seroconversion rate, drug resistance rate, and HCC incidence rate in CHB patients treated with NAs. Meta-analyses were performed with RevMan and Stata/SE software.

Results

Twelve cohort studies and one RCT were selected, in which entecavir (ETV), lamivudine (LAM), telbivudine (LdT), and/or tenofovir disoproxil fumarate (TDF) were evaluated in CHB patients. The meta-analysis showed that ETV was superior to LAM with regard to the HCC incidence (p<0.001), biochemical response (p=0.001), virological response (p=0.02), and drug resistance (p<0.001), and ETV was superior to LdT with regard to the virological response (p<0.001) and drug resistance (p<0.001). We found no significant difference between ETV and TDF with regard to the HCC incidence (p=0.08), biochemical response (p=0.39), virological response (p=0.31), serological conversion (p=0.38), or drug resistance (p=0.95). NA-treated patients with pre-existing cirrhosis had a 5.49 times greater incidence of HCC than those without cirrhosis (p<0.001).

Conclusions

ETV or TDF should be used for long-term first-line monotherapy in CHB patients according to the current guidelines. Standardized protocols are needed for future studies of ETV and TDF to facilitate conclusive comparisons. Patients with cirrhosis are at significantly elevated risk for HCC, despite the benefits of NA treatment.

Nucleos(t)ide Analogues for Reducing Hepatocellular Carcinoma in Chronic Hepatitis B Patients: A Systematic Review and Meta-Analysis

Background/Aims

Studies have shown that nucleos(t)ide analogue (NA) treatment can reduce the risk of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients, but it is unclear which NA is most effective. We performed a meta-analysis and systematic review comparing the efficacies of NAs in CHB patients.

Methods

We searched literature databases for randomized controlled trials (RCTs) and observational studies that analyzed the hepatic biochemical response, virological response, seroconversion rate, drug resistance rate, and HCC incidence rate in CHB patients treated with NAs. Meta-analyses were performed with RevMan and Stata/SE software.

Results

Twelve cohort studies and one RCT were selected, in which entecavir (ETV), lamivudine (LAM), telbivudine (LdT), and/or tenofovir disoproxil fumarate (TDF) were evaluated in CHB patients. The meta-analysis showed that ETV was superior to LAM with regard to the HCC incidence (p<0.001), biochemical response (p=0.001), virological response (p=0.02), and drug resistance (p<0.001), and ETV was superior to LdT with regard to the virological response (p<0.001) and drug resistance (p<0.001). We found no significant difference between ETV and TDF with regard to the HCC incidence (p=0.08), biochemical response (p=0.39), virological response (p=0.31), serological conversion (p=0.38), or drug resistance (p=0.95). NA-treated patients with pre-existing cirrhosis had a 5.49 times greater incidence of HCC than those without cirrhosis (p<0.001).

Conclusions

ETV or TDF should be used for long-term first-line monotherapy in CHB patients according to the current guidelines. Standardized protocols are needed for future studies of ETV and TDF to facilitate conclusive comparisons. Patients with cirrhosis are at significantly elevated risk for HCC, despite the benefits of NA treatment.

An expert review on the use of tenofovir alafenamide for the treatment of chronic hepatitis B virus infection in Asia

Asia has intermediate-to-high prevalence and high morbidity of hepatitis B virus (HBV) infection. The use of guideline-recommended nucleos(t)ide analogs with high barrier to resistance, such as entecavir (ETV), tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF), is one of the key interventions for curbing HBV infection and associated morbidity in Asia. However, there are some challenges to the use of ETV and TDF; while ETV is associated with high resistance in lamivudine (LAM)-exposed (especially LAM-refractory) patients; bone and renal safety issues are a major concern with TDF. Hence, a panel of twenty-eight expert hepatologists from Asia convened, reviewed the literature, and developed the current expert opinion-based review article for the use of TAF in the resource-constrained settings in Asia. This article provides a comprehensive review of two large, phase 3, double-blind, randomized controlled trials of TAF versus TDF in HBeAg-negative (study 0108) and HBeAg-positive (study 0110) chronic HBV patients (> 70% Asians). These studies revealed as follows: (1) non-inferiority for the proportion of patients who had HBV DNA < 29 IU/mL; (2) significantly high rate of normalization of alanine aminotransferase levels; (3) no incidence of resistance; and (4) significantly better bone and renal safety, with TAF vs. TDF up to 144 weeks. Considering the benefits of TAF, the expert panel proposed recommendations for optimizing the use of TAF in Asia, along with guidance on specific patient groups at risk of renal or bone disease suitable for TAF therapy. The guidance provided in this article may help clinicians optimize the use of TAF in Asia.

Influence of antiretroviral therapy on bone metabolism of patients with chronic hepatitis B: a review

Hepatitis B is a major public health problem worldwide and associated with significant mortality. To prevent or delay the deleterious effects of chronic infection by the hepatitis B virus, patients should be carefully followed, and antiviral therapy indicated according to specific recommendations. Currently, available drugs inhibit viral replication and slow or stop the progression of inflammation and fibrosis of the liver. However, the drugs for oral use in the treatment of hepatitis B, jointly referred to as nucleoside/nucleotide analogs, are indicated for prolonged use and have potential side effects. The reduction in bone mineral density was associated with the use of tenofovir, already evaluated in patients infected with HIV because the drug is also part of the therapeutic arsenal for this viral infection. There are few studies on the effects of tenofovir in patients with mono hepatitis B. Therefore, this literature review proposes to examine how hepatitis B acts in the body and the mechanisms by which antiretroviral drugs (especially tenofovir) can affect bone metabolism.

Direct Detection of Drug-Resistant Hepatitis B Virus in Serum Using a Dendron-Modified Microarray

Background/Aims

Direct sequencing is the gold standard for the detection of drug-resistance mutations in hepatitis B virus (HBV); however, this procedure is time-consuming, labor-intensive, and difficult to adapt to high-throughput screening. In this study, we aimed to develop a dendron-modified DNA microarray for the detection of genotypic resistance mutations and evaluate its efficiency.

Methods

The specificity, sensitivity, and selectivity of dendron-modified slides for the detection of representative drug-resistance mutations were evaluated and compared to those of conventional slides. The diagnostic accuracy was validated using sera obtained from 13 patients who developed viral breakthrough during lamivudine, adefovir, or entecavir therapy and compared with the accuracy of restriction fragment mass polymorphism and direct sequencing data.

Results

The dendron-modified slides significantly outperformed the conventional microarray slides and were able to detect HBV DNA at a very low level (1 copy/μL). Notably, HBV mutants could be detected in the chronic hepatitis B patient sera without virus purification. The validation of our data revealed that this technique is fully compatible with sequencing data of drug-resistant HBV.

Conclusions

We developed a novel diagnostic technique for the simultaneous detection of several drug-resistance mutations using a dendron-modified DNA microarray. This technique can be directly applied to sera from chronic hepatitis B patients who show resistance to several nucleos(t)ide analogues.

Concomitant food intake does not affect the efficacy of entecavir in chronic hepatitis B patients with virological response: a randomized, multicenter, noninferiority trial

Background

Little clinical data are available about the effect of food on the antiviral efficacy of entecavir for chronic hepatitis B virus (HBV) infection. The present study evaluated whether entecavir administration in the fed state had comparable efficacy to the fasted condition for maintenance of viral suppression in HBV-infected patients with virological response on entecavir therapy.

Methods

In this multicenter, randomized, open-label, noninferiority study, patients who were currently receiving entecavir and showed a serum HBV DNA level of <20 IU/mL were randomized to take entecavir either under the fasted or fed condition for 48 weeks.

Results

We randomly assigned 50 patients to the fasted group and 46 patients to the fed group. The full analysis set consisted of 49 patients in the fasted group and 44 patients in the fed group. At week 48, the proportion of patients with HBV DNA <20 IU/mL was not significantly different between the fasted and fed groups (98% vs 100%, P=1.00). The mean log₁₀ HBV DNA changes from baseline were similar between the two groups (−0.004 vs −0.012 log₁₀ IU/mL, P=0.43). There were no significant differences in the proportions of patients with normal alanine aminotransferase (87.8% vs 95.5%, P=0.27) and hepatitis B e-antigen seroconversion (0% vs 6.7%, P=0.47) between the two groups. None of the patients showed viral breakthrough. In pharmacokinetic analysis, the maximum concentration and the area under the concentration– time curve to the last quantifiable concentration decreased by 26.4% and 9.3%, respectively, in the fed group compared with the fasted group. However, the differences between two groups were not statistically significant (P=0.28 and 0.83, respectively).

Conclusion

In patients with virological response under entecavir therapy, concomitant food intake did not affect the antiviral efficacy. For patients with adherence problem, taking entecavir with food may be considered to improve compliance.

Risk of HBV reactivation in patients with B-cell lymphomas receiving obinutuzumab or rituximab immunochemotherapy

Risk of hepatitis B virus (HBV) reactivation was assessed in B-cell non-Hodgkin lymphoma (NHL) patients with resolved HBV infection (hepatitis B surface antigen negative, hepatitis B core antibody positive) who received obinutuzumab- or rituximab-containing immunochemotherapy in the phase 3 GOYA and GALLIUM studies. HBV DNA monitoring was undertaken monthly to 1 year after the last dose of study drug. In case of HBV reactivation (confirmed, HBV DNA ≥29 IU/mL), immunochemotherapy was withheld and nucleos(t)ide analog treatment (preemptive NAT) started. Immunochemotherapy was restarted if HBV DNA became undetectable or reactivation was not confirmed, and discontinued if HBV DNA exceeded 100 IU/mL on NAT. Prophylactic NAT was allowed by investigator discretion. Among 326 patients with resolved HBV infection, 27 (8.2%) had HBV reactivation, occurring a median of 125 days (interquartile range, 85-331 days) after the first dose. In 232 patients without prophylactic NAT, 25 (10.8%) had HBV reactivation; all received preemptive NAT. Ninety-four patients received prophylactic NAT; 2 (2.1%) had HBV reactivation. No patients developed HBV-related hepatitis. On multivariate Cox analysis, detectable HBV DNA at baseline was strongly associated with an increased risk of reactivation (adjusted hazard ratio [HR], 18.22; 95% confidence interval [CI], 6.04-54.93; P < .0001). Prophylactic NAT was strongly associated with a reduced risk (adjusted HR, 0.09; 95% CI, 0.02-0.41; P = .0018). HBV DNA monitoring-guided preemptive NAT was effective in preventing HBV-related hepatitis during anti-CD20-containing immunochemotherapy in B-cell NHL patients with resolved HBV infection. Antiviral prophylaxis was also effective and may be appropriate for high-risk patients. These trials were registered at www.clinicaltrials.gov as NCT01287741 (GOYA) and NCT01332968 (GALLIUM).

Management of chronic viral hepatitis in the hematological patient

INTRODUCTION

Infection with HBV and HCV represents a growing challenge in the management of patients with hematological malignancies. Recently, hepatitis E (HEV) was recognized as an endemic infection in developed countries and as an emerging health problem in immunocompromised patients. Areas covered: We reviewed the current knowledge on the impact of chronic viral hepatitis in the hematological setting. Epidemiological features, screening strategies and indications for treatment and monitoring have been explored and commented. Expert commentary: Knowing patient's complete HBV serostatus is mandatory in order to choose between treatment, prophylaxis or a pre-emptive approach. Recent guidelines favor treatment with high barrier molecules in all patients with chronic HBV infection and long lasting prophylaxis with those with inactive or resolved one. With regard to HCV, the new direct-acting antiviral agents have been safely administered in the hematological setting. Their use as first-line single treatment in indolent lymphomas, and combined with chemotherapy in aggressive ones, should be considered. Due to the existing risk of chronic HEV infection in the immunocompromised, screening with serum HEV-RNA should be performed in case of signs and symptoms indicative of hepatitis. In the event of HEV infection, reduction of immunosuppression and, if not feasible or unsuccessful, ribavirin treatment should be prescribed.

Pharmacokinetic evaluation of besifovir for the treatment of HBV infection

INTRODUCTION

Besifovir (LB80380) is a relatively new oral acyclic nucleotide phosphonate. We reviewed the pharmacokinetic characteristics of LB80380 and discussed its role in the treatment of chronic hepatitis B infection. Areas covered: LB80380 is a prodrug of LB80331 and LB80317. It is rapidly absorbed when taken orally. Escalating doses of besifovir produce linear increase of the plasma concentration. Doses above 60mg are effective for inhibiting HBV in human. Using 60mg as an example, the maximal concentration of LB80331 in plasma is 397 ng/mL. The time required to reach maximal concentration in plasma and elimination half-life are 2.0 and 3.0 h, respectively. Besifovir and its metabolites are mainly excreted via the kidneys. Its antiviral efficacy is non-inferior to ETV 0.5mg daily. It is generally safe in terms of renal and bone toxicity. The most common adverse event is carnitine depletion which affects almost all patients on besifovir requiring carnitine supplementation. Expert opinion: Besifovir demonstrated predictable pharmacokinetic characteristics in human subjects. Few clinical studies on besifovir have been conducted. More data are expected particularly for special populations. The adverse events upon long term exposure should be monitored. Large scale head-to-head trials comparing besifovir with existing NA, especially tenofovir alafenamide, should be conducted.

Clinical characteristics of patients with chronic hepatitis B who developed genotypic resistance to entecavir: Real-life experience

BACKGROUND/AIMS

Clinical characteristics of patients with chronic hepatitis B (CHB) who developed genotypic resistance to entecavir (ETV) were compared to those without resistance.

METHODS

Two hundred fifty eight CHB patients who underwent ETV treatment in our institution from July 2007 to May 2013 were included.

RESULTS

Eight (3.1%) patients developed genotypic resistance to ETV during the follow-up period. The patterns of genotypic resistance to ETV were as follows: L180M + M204V + S202G (n=3); M204I + V173M (n=1); I169V + V173M (n=1); L180M + M204V + V173L (n=1); L180M + M204V + V173L + M250V (n=1); M204I + V214A + P237H (n=1). The cumulative occurrence rates of genotypic resistance to ETV were not significantly different between CHB patients with prior nucleos(t)tide analogues (NA) exposure (NA experienced, n=56) and NA naïve patients (n=202, P=0.823 by log rank comparison). Older age, higher baseline log10hepatitis B virus-deoxynucleic acid (log10HBV-DNA), higher log10HBV-DNA at 3, 6, 12 and 24 months after baseline, and complete virologic response (CVR, undetectable serum HBV-DNA by polymerase chain reaction 6 months after ETV treatment) were significant contributors to the development of genotypic resistance to ETV. Multivariate analyses showed higher log10HBV-DNA 6 months after baseline and absence of CVR were independent and significant contributors to the development of ETV resistance.

CONCLUSIONS

Clinical characteristics of patients who developed ETV resistance were higher log10HBV-DNA 6 months after baseline and absence of CVR during the ETV treatment.

Tenofovir has inferior efficacy in adefovir-experienced chronic hepatitis B patients compared to nucleos(t)ide-naïve patients

Background/Aims

A recent study reported that entecavir had inferior efficacy in nucleos(t)ide analogue (NA)-experienced chronic hepatitis B (CHB) patients compared to NA-naïve patients. We sought to compare the efficacy of tenofovir disoproxil fumarate (TDF) in NA-experienced and NA-naïve CHB patients.

Methods

We retrospectively enrolled 252 consecutive patients who had a serum hepatitis B virus (HBV) DNA level greater than 2,000 IU/mL at the initiation of TDF treatment and who received TDF for at least 6 months. Complete virologic suppression (CVS) was defined as undetectable serum HBV DNA. We generated a multivariate Cox proportional-hazard model to examine predictive factors that were independently associated with time to CVS.

Results

The mean age of patients was 48.2 years, and the cohort included 181 NA-naïve patients and 71 NA-experienced patients. The median duration of TDF treatment was 14.4 (interquartile range, 9.5-17.8) months. A total of 167 (92.3%) of 181 NA-naïve patients achieved CVS, and 60 (84.5%) of 71 NA-exposed patients achieved CVS. Forty-nine (89.1%) of 55 patients who previously took an NA aside from adefovir and 11 (68.8%) of 16 adefovir-experienced patients achieved CVS. In multivariable analysis, previous adefovir exposure significantly influenced time to CVS (hazard ratio, 0.37; 95% confidence interval, 0.19-0.72; P=0.003), after adjusting for HBeAg positivity, baseline HBV DNA level and cirrhosis.

Conclusions

Tenofovir had inferior efficacy in adefovir-experienced CHB patients compared to NA-naïve patients. The response of patients with previous adefovir exposure to TDF monotherapy should be monitored closely.

Tenofovir disoproxil fumarate (TDF) vs. emtricitabine (FTC)/TDF in lamivudine resistant hepatitis B: A 5-year randomised study

BACKGROUND & AIMS

Long-term treatment with tenofovir disoproxil fumarate (TDF) alone, or in combination with emtricitabine (FTC) is associated with sustained viral suppression in patients with lamivudine resistant (LAM-R) chronic hepatitis B (CHB).

METHODS

LAM-R CHB patients were randomised 1:1 to receive TDF 300mg or FTC 200mg and TDF 300mg once daily in a prospective, double blind, study. The proportion of patients with plasma hepatitis B virus (HBV) DNA<69IU/ml (<400copies/ml) at week 96 (primary efficacy endpoint) was reported previously. Here we present week 240 follow-up data.

RESULTS

Overall, 280 patients were randomised to receive TDF (n=141) or FTC/TDF (n=139), and 85.4% completed 240weeks of treatment. At week 240, 83.0% of patients in the TDF arm, and 82.7% of patients in the FTC/TDF treatment arm had HBV DNA<69IU/ml (p=0.96). Rates of normal alanine aminotransferase (ALT) and normalised ALT were similar between groups (p=0.41 and p=0.97 respectively). Hepatitis B e antigen loss and seroconversion at week 240 were similar between groups, (p=0.41 and p=0.67 respectively). Overall, six patients achieved hepatitis B surface antigen (HBsAg) loss and one patient (FTC/TDF arm) had HBsAg seroconversion by week 240. No TDF resistance was observed up to week 240. Treatment was generally well tolerated, and renal events were mild and infrequent (∼8.6%). The mean change in bone mineral density at week 240 was -0.98% and -2.54% at the spine and hip, respectively.

CONCLUSIONS

TDF monotherapy was effective and well tolerated in LAM-R CHB patients for up to 240weeks.

LAY SUMMARY

The goal of oral antiviral treatment for chronic hepatitis B (CHB) is to achieve and maintain undetectable HBV DNA levels. Treatment options with enhanced potency, and low risk of resistance development for patients infected with lamivudine resistant (LAM-R) HBV are required. Tenofovir disoproxil fumarate (TDF) monotherapy was effective and well tolerated without TDF resistance development in CHB patients with LAM-R, for up to 240weeks. Clinical trial number: NCT00737568.

Hepatitis B Reactivation During Immunosuppressive Therapy or Cancer Chemotherapy, Management, and Prevention: A Comprehensive Review-Screened

CONTEXT

Due to the close relationship between the immune system and the hepatitis B virus (HBV) replication, it is essential to monitor patients with current or past HBV infection under any type of immunosuppression. Cancer chemotherapy, immunosuppressive therapies in autoimmune diseases, and immunosuppression in solid organ and stem cell transplant recipients are the major reasons for hepatitis B virus reactivation (HBVr). In this review, the challenges associated with HBVr are discussed according to the latest studies and guidelines. We also discuss the role of treatments with different risks, including anti-CD20 agents, tumor necrosis factor-alpha (TNF-α) inhibitors, and other common immunosuppressive agents in various conditions.

EVIDENCE ACQUISITION

Through an electronic search of the PubMed, Google Scholar, and Scopus databases, we selected the studies associated with HBVr in different conditions. The most recent recommendations were collected in order to reach a consensus on how to manage patients at risk of HBVr.

RESULTS

It was found that the positive hepatitis B surface antigen (HBsAg), the high baseline HBV DNA level, the positive hepatitis B virus e antigen (HBeAg), and an absent or low hepatitis B surface antibody (HBsAb) titer prior to starting treatment are the most important viral risk factors. Furthermore, rituximab, anthracycline, and different types of TNF-α inhibitors were identified as the high-risk therapies. By analyzing the efficiency of prophylaxis on the prevention of HBVr, it was concluded that those with a high risk of antiviral resistance should not be used in long-term immunosuppressants. Receiving HBV antiviral agents at the commencement of immunosuppressant therapy or chemotherapy was demonstrated to be effective in decreasing the risk of HBVr. Prophylaxis could also be initiated before the start of therapy. For most immune suppressive regimes, antiviral therapy should be kept up for at least 6 months after the cessation of immunosuppressive drugs. However, the optimal time of prophylaxis keeping should be increased in cases associated with rituximab or hematopoietic stem cell transplants. According to the latest studies and guidelines from different bodies, recommendations regarding screening, monitoring, and management of HBVr are outlined.

CONCLUSIONS

Identification of patients at the risk of HBVr before immunosuppressive therapy is an undeniable part of treatment. Starting the antiviral therapy, based on the type of immunosuppressive drugs and the underlying disease, could lead to better management of disease.

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.

Combined Analysis of the Prevalence of Drug-Resistant Hepatitis B Virus in Antiviral Therapy-Experienced Patients in Europe (CAPRE)

BACKGROUND

European guidelines recommend treatment of chronic hepatitis B virus infection (CHB) with the nucleos(t)ide analogs (NAs) entecavir or tenofovir. However, many European CHB patients have been exposed to other NAs, which are associated with therapy failure and resistance. The CAPRE study was performed to gain insight in prevalence and characteristics of NA resistance in Europe.

METHODS

A survey was performed on genotypic resistance testing results acquired during routine monitoring of CHB patients with detectable serum hepatitis B virus DNA in European tertiary referral centers.

RESULTS

Data from 1568 patients were included. The majority (73.8%) were exposed to lamivudine monotherapy. Drug-resistant strains were detected in 52.7%. The most frequently encountered primary mutation was M204V/I (48.7%), followed by A181T/V (3.8%) and N236T (2.6%). In patients exposed to entecavir (n = 102), full resistance was present in 35.3%. Independent risk factors for resistance were age, viral load, and lamivudine exposure (P < .001).

CONCLUSIONS

These findings support resistance testing in cases of apparent NA therapy failure. This survey highlights the impact of exposure to lamivudine and adefovir on development of drug resistance and cross-resistance. Continued use of these NAs needs to be reconsidered at a pan-European level.

Comparison of the Efficacy of Entecavir and Tenofovir in Nucleos(T)ide Analogue-Experienced Chronic Hepatitis B Patients

The efficacy of entecavir (ETV) and tenofovir (TDF) for the treatment of nucleos(t)ide analogue (NA)-experienced chronic hepatitis B (CHB) patients has been little studied. Here, we compare the efficacy of both ETV and TDF in NA-experienced CHB patients without detectable genotypic resistance. This retrospective cohort study included consecutive NA-experienced patients who had neither current nor previous genotypic resistance and had received ETV or TDF for at least 6 months. Overall, 202 patients (146 patients in the ETV group and 56 in the TDF group) were analyzed. The cumulative probabilities of complete virologic suppression (CVS) at month 12 were 76.1% in the ETV group and 95.0% in the TDF group (P<0.001), respectively. The TDF-treated group achieved CVS more rapidly than the ETV group for both Hepatitis B e antigen (HBeAg)-negative and -positive patients (P = 0.006 and < 0.001, respectively), and for those with both low (< 2,000 IU/mL) and high (≥ 2,000 IU/mL) HBV DNA levels (P = 0.01 and 0.002, respectively). TDF group had an increased probability of achieving CVS (hazard ratio, 2.242; 95% confidence interval, 1.587-3.165; P = 0.001), after adjustment for HBV DNA level, the presence of HBeAg, and a history of CVS during prior treatment. During the treatment period, 23 patients (15.8%) in the ETV group developed virologic breakthrough, compared to none in the TDF group. The cumulative probabilities of developing virologic breakthrough and ETV-resistance at month 24 were 9.7% and 5.3%, respectively. In conclusion, TDF is preferable to ETV for achieving CVS in NA-experienced CHB patients without genotypic resistance.

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.

Clinical relevance of hepatitis B virus variants

The hepatitis B virus (HBV) is a global public health problem with more than 240 million people chronically infected worldwide, who are at risk for end-stage liver disease and hepatocellular carcinoma. There are an estimated 600000 deaths annually from complications of HBV-related liver disease. Antiviral therapy with nucleos/tide analogs (NA) targeting the HBV polymerase (P) can inhibit disease progression by long-term suppression of HBV replication. However, treatment may fail with first generation NA therapy due to the emergence of drug-resistant mutants, as well as incomplete medication adherence. The HBV replicates via an error-prone reverse transcriptase leading to quasispecies. Due to overlapping open reading frames mutations within the HBV P can cause concomitant changes in the HBV surface gene (S) and vice versa. HBV quasispecies diversity is associated with response to antiviral therapy, disease severity and long-term clinical outcomes. Specific mutants have been associated with antiviral drug resistance, immune escape, liver fibrosis development and tumorgenesis. An understanding of HBV variants and their clinical relevance may be important for monitoring chronic hepatitis B disease progression and treatment response. In this review, we will discuss HBV molecular virology, mechanism of variant development, and their potential clinical impact.

Practical approach in hepatitis B e antigen-negative individuals to identify treatment candidates

The natural history of chronic hepatitis B is characterized by different phases of infection, and patients may evolve from one phase to another or may revert to a previous phase. The hepatitis B e antigen (HBeAg)-negative form is the predominant infection worldwide, which consists of individuals with a range of viral replication and liver disease severity. Although alanine transaminase (ALT) remains the most accessible test available to clinicians for monitoring the liver disease status, further evaluations are required for some patients to assess if treatment is warranted. Guidance from practice guidelines together with thorough investigations and classifications of patients ensure recognition of who needs which level of care. This article aims to assist physicians in the assessment of HBeAg-negative individuals using liver biopsy or non-invasive tools such as hepatitis B s antigen quantification and transient elastography in addition to ALT and hepatitis B virus DNA, to identify who will remain stable, who will reactivate or at risk of disease progression hence will benefit from timely initiation of anti-viral therapy.