Options for the management of antiviral resistance during hepatitis B therapy: reflections on battles over a decade

How to Effectively Monitor Aging Patients with Chronic Hepatitis B: A Review

Hepatitis B virus (HBV) infection is a major global public health challenge associated with significant morbidity and mortality. Due to worldwide population aging, HBV infection in the elderly will become increasingly prevalent. Effective universal vaccination programs exist but these are largely targeted towards the younger population. Therefore, the elderly population remains at risk of higher disease burden. New diagnoses of HBV infection in the elderly are usually asymptomatic chronic infections which increases their risk of developing cirrhosis, hepatocellular carcinoma, and liver disease-related mortality, especially if left untreated. Physiological changes and the increasing prevalence of multimorbidity associated with aging also potentially worsen outcomes in elderly patients with chronic HBV infection. Therefore, this cohort of patients should be monitored closely and effectively. Current international clinical practice guidelines unfortunately do not provide hard treatment endpoints specific to elderly patients with chronic HBV infection. Management of these patients is complex and requires an individualized approach. Multiple factors such as physiological changes, comorbidities, compliance, treatment tolerability and efficacy, burden of treatment, and realistic treatment goals need to be considered. Shared decision-making between patient and clinician is essential to ensure that the final decision for or against treatment aligns with the patient's values and preferences. This review article aims to summarize the monitoring and management of chronic HBV infection in the aging population.

Extrahepatic carcinogenicity of oral nucleos(t)ide analogues in chronic hepatitis B carriers: A 35,000-Korean outcome study

Evidence on the carcinogenicity of oral nucleos(t)ide analogues (NAs) is inconclusive and lacks data on the effects by chemical structure of the NAs in patients with chronic hepatitis B (CHB). We aimed to provide definitive results on this issue using a large set of CHB patients and data on all major NA drugs. The study population consisted of 10,331 patients with CHB receiving primary NA treatment for more than 6 months, and 24,836 untreated controls followed for at least as long as the treated patients. Using the inverse-probability-of-treatment-weighted (IPTW) method, the cumulative incidence of extrahepatic cancers was compared in the treated and untreated patients and across the cyclopentane, L-nucleoside and acyclic phosphonate categories of NAs. Analyses of individual cancers as sub-endpoints were also performed. The cumulative incidence of overall extrahepatic malignancies did not differ between the two groups in the IPTW cohort (hazard ratio [HR] 1.002; 95% confidence interval [CI] [0.859-1.169]). Similar statistical trends were observed in analyses across the three NA chemical subsets and controls. Per-cancer analyses indicated that NA treatment was significantly associated with increased risks of colorectal/anal cancers (HRs [95% CI], 1.538 [1.175-2.013]) and lymphoma (1.784 [1.196-2.662]). Conversely, breast cancer (HRs [95% CI], 0.669 [0.462-0.967]) and prostate cancer (0.521 [0.329-0.825]) were less prevalent in the NA-treated group. In conclusion, prolonged NA treatment presents carcinogenic risks for colorectal/anal and lymphoid tissues in CHB patients, although it does not affect most extrahepatic organs. The protective effect of NAs on breast and prostate cancers should be confirmed.

Treatment Algorithm for Managing Chronic Hepatitis B Virus Infection in the United States: 2021 Update

BACKGROUND & AIMS

Chronic hepatitis B (CHB) infection remains the most frequent etiology of hepatocellular carcinoma globally as well as a major cause of cirrhosis. Despite vaccination, substantial numbers of persons have already been infected with hepatitis B virus and remain at risk of progressive liver disease.

METHODS

In 2004, a CHB management algorithm was developed by a panel of North American hepatologists, which was subsequently updated in 2006, 2008, and 2015. Since the most recent version, several developments have altered the management of CHB. Tenofovir alafenamide, with a more favorable safety profile than tenofovir disoproxil fumarate, has been introduced as an initial antiviral choice as well as an alternative for long-term therapy. Quantitation of hepatitis B surface antigen is becoming more widely available in clinical practice, with implications for monitoring response to treatment. Additionally, there has been a shift in how the natural history of CHB is perceived, as newer evidence has challenged the concept that during the immunotolerant phase of infection disease progression is not a concern. Finally, recent analyses indicate that in the United States, the average age of patients with CHB has increased, implying that the presence of comorbidities, including metabolic liver disease, increasing use of biologics associated with aging will increasingly affect disease management.

RESULTS

This updated algorithm is intended to serve as a guide to manage CHB while new antiviral strategies are developed.

CONCLUSIONS

Recommendations have been based on evidence from the scientific literature, when possible, as well as clinical experience and consensus expert opinion. Points of continued debate and areas of research need are also described.

Maintaining Antiviral Efficacy after Switching to Generic Entecavir 1 mg for Antiviral-resistant Chronic Hepatitis B

Background/Aims

Clinical equivalence of generic antiviral agents for chronic hepatitis B (CHB) has not been demonstrated, particularly in cases with previous antiviral resistance. Entecavir 1 mg is prescribed frequently as a mono- or combination therapy in antiviral-resistant CHB patients. This study evaluated the efficacy and safety of switching to generic entecavir 1 mg (Baracle^®) in CHB patients taking brand-name entecavir 1 mg (Baraclude^®) alone or in combination with other nucleotide analogs after the development of antiviral resistance.

Methods

This study was a single-arm prospective study. The primary endpoint was undetectable HBV DNA (<20 IU/mL) at 12 months after switching treatment. The biochemical and serologic responses, virologic breakthrough, and antiviral resistance rates were also evaluated.

Results

Forty CHB patients with undetectable HBV DNA through the brand-name entecavir 1 mg treatment as a mono- or combination therapy after developing antiviral resistance to nucleos(t)ide analogs were enrolled in this study. No significant difference in the HBV DNA non-detection rate was observed between the baseline and 12 months after switching therapy (p=0.324). Furthermore, non-inferiority of the generic entecavir 1 mg to the brand-name entecavir 1 mg with 10% margin in maintaining undetectable HBV DNA was demonstrated (95% CI -2.80 to 8.20%). Similarly, no difference in the biochemical response rate was observed after switching therapy. Serum hepatitis B e antigen loss was observed in 12.5%. No virologic breakthrough was reported.

Conclusions

Generic entecavir 1 mg is a reasonable alternative to the brand-name entecavir 1 mg in antiviral-resistant CHB patients with viral suppression.

Tenofovir-based combination therapy or monotherapy for multidrug-resistant chronic hepatitis B: Long-term data from a multicenter cohort study

The treatment of multidrug-resistant (MDR) chronic hepatitis B (CHB) is challenging. Herein, we report a multicenter prospective cohort study for the evaluation of tenofovir disoproxil fumarate (TDF)-based therapy for MDR CHB in a real-life setting. The inclusion criteria comprised patients with resistance to more than two nucleos(t)ide analogue (NA) classes and hepatitis B virus (HBV) DNA level of ≥200 IU/mL. The primary end-point was virologic response (VR), defined as undetectable HBV DNA (<20 IU/mL) after 60 months. A total of 236 patients met the inclusion criteria. The mean HBV DNA level was 4.16 ± 1.44 log IU/mL; 26.7% of patients had liver cirrhosis. Before the initiation of TDF, 33.5%, 44.9% and 21.6% of patients had mutations resistant to L-NA + adefovir, L-NA + entecavir (ETV) and L-NA + adefovir + ETV, respectively. A total of 184 patients received TDF-based combination therapy [TDF + ETV (n = 178) or TDF + L-NA (n = 6)], and 52 patients received TDF monotherapy. In the entire cohort, the VR rates were 77.2%, 89.9% and 92.2% at 12, 36 and 60 months, respectively. The VR rates were not significantly different between the combination therapy and the monotherapy group after 12 (76.2% vs 80.4%, P = .533), 36 (89.8% vs 90.3%, P = 1.000) or 60 (92.9% vs 87.5%, P = .499) months. Also, there was no significant difference in the cumulative VR rates for 5 years between the treatment groups (P = .910). Newly developed antiviral resistance was not observed. TDF-based therapy was effective for the treatment of MDR CHB. The efficacy of TDF monotherapy was not different from that of the TDF-based combination therapy.

Comparison of clinical practice guidelines for the management of chronic hepatitis B: When to start, when to change, and when to stop

Clinical practice guidelines are important for guiding the management of specific diseases by medical practitioners, trainees, and nurses. In some cases, the guidelines are utilized as a reference for health policymakers in controlling diseases with a large public impact. With this in mind, practice guidelines for the management of chronic hepatitis B (CHB) have been developed in the United States, Europe, and Asian-Pacific regions to suggest the best-fit recommendations for each social and medical circumstance. Recently, the Korean Association for the Study of the Liver published a revised version of its clinical practice guidelines for the management of CHB. The guidelines included updated information based on newly available antiviral agents, the most recent opinion on the initiation and cessation of treatment, and updates for the management of drug resistance, partial virological response, and side effects. Additionally, CHB management in specific situations was comprehensively revised. This review compares the similarities and differences among the various practice guidelines to identify unmet needs and improve future recommendations.

Companion and complementary diagnostics for infectious diseases

INTRODUCTION

Companion diagnostics (CDx) are important in oncology therapeutic decision-making, but specific regulatory-approved CDx for infectious disease treatment are officially lacking. While not approved as CDx, several ID diagnostics are used as CDx. The diagnostics community, manufacturers, and regulatory agencies have made major efforts to ensure that diagnostics for new antimicrobials are available at or near release of new agents.

AREAS COVERED

This review highlights the status of Complementary and companion diagnostic (c/CDx) in the infectious disease literature, with a focus on genotypic antimicrobial resistance testing against pathogens as a class of diagnostic tests.

EXPERT OPINION

CRISPR, sepsis markers, and narrow spectrum antimicrobials, in addition to current and emerging technologies, present opportunities for infectious disease c/CDx. Challenges include slow guideline revision, high costs for regulatory approval, lengthy buy in by agencies, discordant pharmaceutical/diagnostic partnerships, and higher treatment costs. The number of patients and available medications used to treat different infectious diseases is well suited to support competing diagnostic tests. However, newer approaches to treatment (for example, narrow spectrum antibiotics), may be well suited for a small number of patients, i.e. a niche market in support of a CDx. The current emphasis is rapid and point-of-care (POC) diagnostic platforms as well as changes in treatment.

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.

The management of hepatitis B and hepatitis C in children

In the present paper, we review the increased disease burden of hepatitis B (HBV) and hepatitis C (HCV) infection that is recognized worldwide; especially in children when the most common mode of transmission is vertically from infected mothers. In children with HBV and HCV infection, spontaneous clearance of the virus in the first years of life is not common, in contrast with adults, but these patients often stay asymptomatic until early adulthood, when disease has progressed to chronic hepatitis with increased risk of cirrhosis and its complication, and hepatocellular carcinoma. Due to limited treatment options of HBV infection in the pediatric population, clinicians focus on primary prevention, by vaccinating all infants during their first days of life. Infants born to infected mothers, receive intravenous immunoglobulin on top of the vaccine, and thus preventing transmission in 95% of the infants. While for HCV infection, since there is no vaccine to prevent HCV disease, providers focus primarily on treatment. The treatment landscape of HCV infection in children rapidly evolves, away from interferon regimens, and towards direct-acting antiviral agents that have a safer and more efficacious drug profile. Currently, there are ongoing clinical trials investigating the efficacy and tolerance of direct-acting agents in children below 12 years of age.

The development of hepatocarcinoma after long-term antivirus treatment of Chinese patients with chronic hepatitis B virus infection: Incidence, long-term outcomes and predictive factors

BACKGROUND

Patients with chronic hepatitis B virus (HBV) infection are at high risk for progressing to decompensated cirrhosis and hepatocellular carcinoma (HCC). Although long-term treatment with nucleos(t)ide analogues (NAs) benefits patients with chronic hepatitis B (CHB), many develop HCC. Therefore, the clinical outcomes of patients CHB who undergo long-term treatment with NAs remain to be identified. The aim of this study therefore was to evaluate the risk and predictors of patients with CHB who develop hepatitis B-induced HCC.

METHODS

We investigated 1200 patients with CHB who were treated with NAs for at least four years and evaluated the association of the variables ALT, HBsAg, HBV DNA, age and platelet count with the occurrence of HCC. We used multivariable analysis to identify independent risk factors for the development of HCC.

RESULTS

HCC developed in 153 NA-treated patients. Serum HBV DNA levels of 18.17% (218/1200) patients were>2000IU/mL. The median level of liver stiffness measurement (LSM) of all patients was 8.3±6.7kPa vs. 19.8±10.1kPa in patients with HCC. Advanced age, lower platelet counts, positive HBV DNA load, lower ALB concentration and relatively advanced liver disease were associated with an increased risk of developing HCC. Further, TGF-β and IFN-γ levels were higher and lower in patients with HCC or CHB, respectively.

CONCLUSIONS

Hepato-carcinogenesis occurred more frequently in patients with a positive HBV DNA load and relatively advanced liver disease. Therefore, it is important to administer antiviral therapy to patients with CHB before they develop HBV-related cirrhosis.

A Review of Antiviral Use for the Treatment of Chronic Hepatitis B Virus Infection in Pregnant Women

Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) remains high even with the proper use of active-passive immunoprophylaxis in newborns. Mothers with significant viremia are at a much higher risk of MTCT; therefore, treatments aimed at lowering HBV DNA levels during pregnancy may ultimately decrease global disease burden. The exact threshold for treatment remains controversial; however, most studies have accepted levels greater than 2 × 5 log₁₀ IU/mL as significant viremia. We reviewed the most recent literature on antiviral efficacy, maternal and fetal safety, and viral resistance patterns when used for short-duration therapy in pregnancy. The literature review shows that antiviral therapy during pregnancy significantly reduces maternal HBV DNA levels with subsequent reductions in infant HBV infections. Tenofovir disoproxil fumarate (TDF) is associated with mild gastrointestinal distress and may cause decreased fetal bone growth (although long-term studies are needed to evaluate the clinical significance of this finding), and the impact of this drug is likely limited when use is restricted to the third trimester. Lamivudine and telbivudine remain inferior to TDF in regard to resistance profiles. Overall, TDF, lamivudine, and telbivudine in conjunction with standard immunoprophylaxis are recommended for use in pregnant women with significant HBV viremia (>2 × 5 log₁₀ IU/mL) to prevent MTCT and appear reassuring in regard to their maternal and fetal safety profiles.

Management of Clevudine-Resistant Chronic Hepatitis B: A Multicenter Cohort Study

BACKGROUND/AIMS

Data are lacking regarding the management of chronic hepatitis B (CHB) with resistance to clevudine (CLV). This study evaluated the efficacy of different rescue therapies for CLV-resistant CHB.

METHODS

Patients with CLV-resistant CHB were enrolled in the cohort, and all patients developed virologic breakthrough during CLV therapy and had confirmed-genotypic resistance to CLV (rtM204I mutation) before enrollment.

RESULTS

Of the 107 patients, 12 received adefovir (ADV), 21 received a CLV plus ADV combination (CLV+ADV), 34 received a lamivudine plus ADV combination (LAM+ADV), and 40 received entecavir (ETV) therapy for 48 weeks. The CLV+ADV group had the lowest hepatitis B virus (HBV) DNA level (p<0.0001) and showed the greatest reduction of HBV DNA levels from baseline compared to all other groups (p=0.004) at week 48. HBV DNA was undetectable (<70 IU/mL) in 0%, 57.1%, 21.2%, and 27.5% (p=0.003) of the patients in each group, respectively, at week 48. At the end of the study, the mean alanine transaminase (ALT) level, rate of ALT normalization, and rate of hepatitis B envelope antigen loss or seroconversion did not differ between groups.

CONCLUSIONS

CLV+ADV combination therapy in patients with CLV-resistant CHB more effectively suppresses HBV replication than ETV, ADV, or LAM+ADV therapy.

Identification of UQCRB as an oxymatrine recognizing protein using a T7 phage display screen

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora flavescens Aiton (Radix Sophorae Flavescentis, Kushen) is used in traditional Chinese medicine to treat chronic hepatitis B (CHB), and has the ability to clear heat and dampness from the body. Oxymatrine is one of the major bioactive compounds extracted from Sophora flavescens Aiton and constitutes more than 90% of the oxymatrine injection commonly used for CHB treatment in clinics in China.

AIM OF THE STUDY

We aim to analyze the protein binding target of oxymatrine in treating CHB by screening a T7 phage display cDNA library of human CHB and examine the biochemistry of protein-ligand binding between oxymatrine and its ligands.

MATERIALS AND METHODS

A T7 phage cDNA library of human CHB was biopanned by affinity selection using oxymatrine as bait. The interaction of oxymatrine with its candidate binding protein was investigated by affinity assay, molecular docking, Isothermal Titration Calorimetry (ITC) and Surface Plasmon Resonance (SPR).

RESULTS

A library of potential oxymatrine binding peptides was generated. Ubiquinol-cytochrome c reductase binding protein (UQCRB) was one of the candidate binding proteins of oxymatrine. UQCRB-displaying T7 phage binding numbers in the oxymatrine group were significantly higher than that in the control group, biotin group, and matrine group (p<0.05 or p<0.01). Three-dimensional structure modeling of the UQCRB with oxymatrine showed that their binding interfaces matched and oxymatrine inserted into a deeper pocket of UQCRB, which mainly involved amino acid residues Tyr21, Arg33, Tyr83, Glu84, Asp86, Pro88, and Glu91. The binding affinity constant (Kb) from SPR was 4.2mM. The Kb from ITC experiment was 3.9mM and stoichiometry was fixed as 1, which fit very well with the result of SPR. The binding of oxymatrine to UQCRB was driven by strong enthalpy forces such as hydrogen bonds and polar interactions as the heat released was about 157kcal/mol and ΔG was less than zero.

CONCLUSIONS

In this study, using the T7 phage display system, we have identified UQCRB as a direct binding protein of oxymatrine. Furthermore, the specificity and molecular interaction of oxymatrine with UQCRB were also determined. The binding of UQCRB to oxymatrine suggests that UQCRB is a potential target of oxymatrine in treating CHB. These results provide new understanding into the mechanism of oxymatrine and insights into the strategy on the treatment of CHB.

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.

Tenofovir rescue therapy in chronic hepatitis B patients who failed previous nucleoside analogue treatment

Background

Tenofovir (TDF) is considered as the first line therapy for chronic hepatitis B. This study presents the results of TDF monotherapy in patients who failed previous nucleoside analogue treatment.

Methods

The study included 29 patients treated with TDF 245 mg once daily for 18 months after lamivudine monotherapy (LAM arm: n = 15) or sequential therapy with lamivudine and entecavir (LAM → ETV arm: n = 14). The previous antiviral therapy was discontinued due to lack of efficacy. All patients had HBV DNA between 2.1 and 8.23 log₁₀ IU/ml and 15 were HBeAg-positive, while 45 % of patients had increased ALT activity. Undetectable HBV DNA (<20 IU/ml) at months 3, 6, 12 and 18 was the primary endpoint in the study, while HBeAg/HBsAg loss/seroconversion and ALT normalisation were secondary endpoints.

Results

Primary nonresponse to TDF was not observed. HBV DNA was undetectable in 80, 80, 80 and 93 % in LAM arm and 50, 71, 86 and 86 % in LAM → ETV arm patients, at 3, 6, 12 and 18 months of TDF therapy, respectively. One patient achieved anti-HBeAg seroconversion. 86.5 % of patients had normal ALT activity at the end of the study. The baseline HBV DNA load, HBeAg status and the length of the duration of TDF therapy appeared significantly associated with the response to the therapy. HBV DNA clearance occurred faster in HBeAg-negative patients than in those positive for HBeAg.

Conclusions

TDF is an effective antiviral medication in patients with previous exposure to LAM or LAM and ETV. Final proportion of patients who achieved undetectable HBV DNA and had normal ALT activity in both arms, was similar.

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

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

Management of entecavir-resistant chronic hepatitis B with adefovir-based combination therapies

AIM

To evaluate the long-term efficacy adefovir (ADV)-based combination therapies in entecavir (ETV)-resistant chronic hepatitis B (CHB) patients.

METHODS

Fifty CHB patients with genotypic resistance to ETV at 13 medical centers in South Korea were included for the analysis. All the patients received rescue therapy with the combination of ADV plus ETV (ADV/ETV, n = 23) or ADV plus lamivudine (LMV) (ADV/LMV, n = 27) for more than 12 mo. Patients were monitored at least every 3-4 mo during ADV-based combination therapy by clinical examination as well as biochemical and virological assessments. Hepatitis B virus (HBV) DNA levels were measured by real-time PCR and logarithmically transformed for analysis. Cumulative rates of virologic response (VR; HBV DNA < 20 IU/mL) were calculated using the Kaplan-Meier method, and the difference was determined by a log-rank test. Multivariate logistic regression and Cox proportional hazards models were used to identify independent risk factors significantly associated with short-term and long-term VR, respectively.

RESULTS

Baseline median HBV DNA levels were 5.53 (2.81-7.63) log10 IU/mL. The most commonly observed ETV genotypic mutation sites were rt184 and rt202. Patients were treated for a median of 27 (12-45) mo. Overall, cumulative VR rates at 6, 12, 24, and 36 mo were 26%, 36%, 45%, and 68%, respectively. Patients treated with the ADV/ETV combination showed higher cumulative VR rates (35%, 43%, 65%, and 76%, respectively) than those with the ADV/LAM combination (18%, 30%, 30%, and 62%, respectively; P = 0.048). In the multivariate analysis, low baseline HBV DNA levels (< 5.2 log10 IU/mL) and initial virologic response at 3 mo (IVR-3; HBV DNA < 3.3 log10 IU/mL after 3 mo) were independent predictive factors for VR. Patients with favorable predictors achieved cumulative VR rates up to 90% at 36 mo. During the same period, the cumulative incidence of virologic breakthrough was as low as 6% in patients with the both favorable predictors.

CONCLUSION

If tenofovir is not available, ADV/ETV combination could be considered in ETV-resistant patients with low HBV DNA titers, and may be continued if IVR-3 is achieved.

Substitution at rt269 in Hepatitis B Virus Polymerase Is a Compensatory Mutation Associated with Multi-Drug Resistance

The emergence of compensatory mutations in the polymerase gene of drug resistant hepatitis B virus (HBV) is associated with treatment failure. We previously identified a multi-drug resistant HBV mutant, which displayed resistance towards lamivudine (LMV), clevudine (CLV), and entecavir (ETV), along with a strong replication capacity. The aim of this study was to identify the previously unknown compensatory mutations, and to determine the clinical relevance of this mutation during antiviral therapy. In vitro mutagenesis, drug susceptibility assay, and molecular modeling studies were performed. The rtL269I substitution conferred 2- to 7-fold higher replication capacity in the wild-type (WT) or YMDD mutation backbone, regardless of drug treatment. The rtL269I substitution alone did not confer resistance to LMV, ETV, adefovir (ADV), or tenofovir (TDF). However, upon combination with YMDD mutation, the replication capacity under LMV or ETV treatment was enhanced by several folds. Molecular modeling studies suggested that the rtL269I substitution affects template binding, which may eventually lead to the enhanced activity of rtI269-HBV polymerase in both WT virus and YMDD mutant. The clinical relevance of the rtL269I substitution was validated by its emergence in association with YMDD mutation in chronic hepatitis B (CHB) patients with sub-optimal response or treatment failure to LMV or CLV. Our study suggests that substitution at rt269 in HBV polymerase is associated with multi-drug resistance, which may serve as a novel compensatory mutation for replication-defective multi-drug resistant HBV.

Aligning to the sample-specific reference sequence to optimize the accuracy of next-generation sequencing analysis for hepatitis B virus

Background

Hepatitis B virus (HBV) quasispecies are crucial in the pathogenesis of chronic liver disease. Next-generation sequencing (NGS) is powerful for identifying viral quasispecies. To improve mapping quality and single nucleotide variant (SNV) calling accuracy in the NGS analysis of HBV, we compared different mapping references, including the sample-specific reference sequence, same genotype sequences and different genotype sequences, according to the sample.

Methods

Real Illumina HBV datasets from 86 patients, and simulated datasets from 158 HBV strains in the GenBank database, were used to assess mapping quality. SNV calling accuracy was evaluated using different mapping references to align Real Illumina datasets from a single HBV clone.

Results

Using the sample-specific reference sequence as a mapping reference produced the largest number of mappable reads and coverages. With a different genotype mapping reference, the consensus sequence derived from the Real Illumina datasets of the single HBV clone showed 21 false SNV callings in polymerase and surface genes, the regions most divergent between the mapping reference and this HBV clone. A ~6 % coverage of most of these false SNVs was yielded even with a same genotype mapping reference, but none with the sample-specific reference sequence.

Conclusions

Using sample-specific reference sequences as a mapping reference in NGS analysis optimized mapping quality and the SNV calling accuracy for HBV quasispecies.

Electronic supplementary material

The online version of this article (doi:10.1007/s12072-015-9645-x) contains supplementary material, which is available to authorized users.

Cost-effectiveness analysis of lamivudine, telbivudine, and entecavir in treatment of chronic hepatitis B with adefovir dipivoxil resistance

The purpose of this study was to analyze the cost-effectiveness of lamivudine (LMV), telbivudine (LdT), and entecavir (ETV) in treatment of chronic hepatitis B with adefovir dipivoxil (ADV) resistance. Two hundred and fifty-two patients were recruited and screened for resistance to ADV and randomly assigned into three groups: LMV + ADV, LdT + ADV, and ETV + ADV. The ratio of biochemical response, virological response, seroconversion of hepatitis Be antigen (HBeAg)/hepatitis Be antibody (HBeAb), viral breakthrough, and the cost and effectiveness of treatments were analyzed. A comparison of the results of the ratio of biochemical response, virological response and seroconversion of HBeAg/HBeAb, showed no statistical difference between the three groups, with the economic cost of LMV + ADV the lowest, LdT + ADV the middle, and ETV + ADV the highest. The side effects of the three plans are all rare and tolerable. LMV + ADV is the optimal rescue strategy, and LdT + ADV the alternative selection in the economically less developed regions, while ETV + ADV was used in the economically developed regions.

Efficacy of telbivudine compared with entecavir in hepatitis B virus-related cirrhosis: 2 year follow-up data

BACKGROUND & AIMS

Entecavir (ETV) is effective in the treatment of chronic hepatitis B virus (HBV) infections, even in patients with underlying cirrhosis. However, there is little information on the effect of telbivudine (TBV) in chronic hepatitis B patients with cirrhosis.This study compared the antiviral efficacy of TBV and ETV in HBV-related cirrhosis.

METHODS

We consecutively enrolled 151 treatment-naïve patients with HBV-related cirrhosis who started antiviral therapy with TBV (n = 61) or ETV (n = 90).

RESULTS

After 24 months of treatment, per-protocol analysis showed similar virological response rates (HBV DNA <20 IU/ml) in the TBV group (80.6%, 25/31) and in the ETV group (90.2%, 74/82) (P = 0.167). However, intention-to-treat analysis showed lower virological response rates in the TBV group (41.7%, 25/60) than in the ETV group (83.1%, 74/89) (P = 0.001). Mean reduction in HBV DNA levels was greater in the ETV group (-3.72 ± 1.94 vs. -4.87 ± 1.57 respectively, P = 0.001). Serologic and biochemical response rates at month 24 did not differ significantly between the groups. Child-Turcotte-Pugh score was significantly improved after 24 months compared to the pretreatment state without difference between the groups. During 24 months of therapy, 15 patients (27.3%) showed antiviral resistance to TBV while no resistance (0%) was reported in the ETV group (P = 0.001).

CONCLUSIONS

Compared to ETV, TBV therapy shows lower efficacy in viral suppression and higher risk of antiviral resistance despite comparable effect on improvement of hepatic function for the treatment of HBV-related cirrhosis.

Comparison of lamivudine plus adefovir therapy versus entecavir with or without adefovir therapy for adefovir-resistant chronic hepatitis B

BACKGROUND AND GOALS

Data regarding the management of adefovir (ADV) resistance are still limited. The aim of this study is to investigate treatment outcomes of rescue therapy in ADV-resistant chronic hepatitis B (CHB) patients.

STUDY

CHB patients who began rescue therapy due to documented genotypic resistance mutations to ADV between October 2006 and July 2012 were retrospectively reviewed.

RESULTS

Sixty-three patients were included in this study. Most patients had history of lamivudine (LAM) resistance. Treatment response was evaluated at 3-month intervals up to 12 months. The cumulative rate of complete virologic response (CVR) in hepatitis B virus (HBV)-infected patients (HBV DNA<60 IU/mL) was 15.9%, 27.2%, 28.9%, and 31.7% after 3, 6, 9, and 12 months of rescue therapy. Thirty-five patients were treated with a combination of LAM plus ADV (LAM+ADV group) and 28 patients were treated with entecavir (ETV)-based therapy (ETV with or without ADV therapy, ETV±ADV group). The cumulative CVR rate was significantly higher in the ETV±ADV group than in the LAM+ADV group at month 12 (46.4% vs. 20.6%, respectively, P=0.040). Multivariate analysis showed that pretreatment serum HBV DNA levels at <6 log10 IU/mL (hazard ratio: 34.109, P=0.001) and type of rescue therapy (hazard ratio: 4.944, P=0.036) were associated with CVR.

CONCLUSIONS

Lower baseline HBV DNA level and ETV±ADV therapy were the important predictive factors for CVR in ADV-resistant CHB patients. This study suggests the need of early switching to a rescue therapy such as ETV±ADV at the time of low-level viremia.