Efficacy of entecavir-tenofovir combination therapy for chronic hepatitis B patients with multidrug-resistant strains. Antimicrob Agents Chemother. 2014;58:6710-6716. [PMID: 25155601 DOI: 10.1128/AAC.03845-14]

Efficacy of different nucleoside analog rescue therapies for entecavir-resistant chronic hepatitis B patients

BACKGROUND

Entecavir (ETV) is recommended as a first-line anti-HBV treatment. However, many chronic hepatitis B patients initiate anti-HBV treatment such as lamivudine and telbivudine with low genetic barriers in China, which leads to compensatory mutations and increases the rate of ETV resistance. The management of ETV resistance in China is an essential clinical issue.

METHODS

Patients from 2011 to 2017 with nucleos(t)ide analog resistance were screened and 72 patients with ETV resistance were included. These patients received different rescue therapies including an ETV and adefovir (ADV) combination therapy group (n = 25), a tenofovir (TDF) monotherapy group (n = 27), and an ETV and TDF combination therapy group (n = 20). Virologic, biochemical, and serologic responses were compared among the three groups.

RESULTS

The rate of ETV resistance among all HBV-resistant variants increased from 6.04% in 2011 to 15.02% in 2017. TDF monotherapy and TDF combination groups showed similar rates of negative HBV DNA at 48 weeks (74.07% vs 70.00%, P > 0.05), while the ETV and ADV group showed the worst virologic response (28.00%). Also, TDF monotherapy and TDF combination therapy showed similar decline of HBV DNA at weeks 12, 24, and 48. There was no significant difference in the rates of HBeAg clearance, ALT normalization, and abnormal renal function among the three groups.

CONCLUSIONS

TDF monotherapy showed a comparable virologic response to TDF and ETV combination therapy and a better virologic response than ETV and ADV combination therapy. Thus, TDF monotherapy is the preferred rescue therapy for ETV resistance.

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.

Characterization of Hepatitis B virus polymerase mutations A194T and CYEI and tenofovir disoproxil fumarate or tenofovir alafenamide resistance

Both the A194T and a quadruple mutation CYEI (S106C, H126Y, D134E and L269I) in hepatitis B virus (HBV) polymerase reverse transcriptase domain (pol/RT) are suggested to be associated with treatment failure with tenofovir disoproxil fumarate (TDF). To further evaluate this assertion, the prevalence of these mutations at baseline as well as their development and/or loss during TDF and tenofovir alafenamide (TAF) treatment was analysed in 3886 patients enrolled in Gilead HBV clinical studies. In total, six out of 3886 (0.2%) patients carried the rtA194T mutation, while only 1 patient carried a triple CYE and 2 patients carried a quadruple CYEI mutation at baseline. All the patients harbouring rtA194T or CYE/CYEI at baseline achieved viral suppression by week 96 after TDF or TAF treatment. No patients developed an rtA194T mutation or > 1 substitution of CYEI, and the number of patients losing any substitutions of CYEI (n = 17) was similar to the number who developed a single substitution of CYEI (n = 32) during treatment. Phenotypic evaluation of the site-directed mutant (SDM) panel containing these mutations with or without other resistance mutations did not demonstrate a significant shift in TFV and TAF potency in vitro. No evidence of rtA194T and CYEI conferring resistance to TDF or TAF was observed based on the treatment responses to TDF or TAF in patients with mutations at baseline, the lack of selection of mutations after starting TDF or TAF treatment and no change in susceptibility to TFV or TAF in vitro.

Investigating Core Signaling Pathways of Hepatitis B Virus Pathogenesis for Biomarkers Identification and Drug Discovery via Systems Biology and Deep Learning Method

Hepatitis B Virus (HBV) infection is a major cause of morbidity and mortality worldwide. However, poor understanding of its pathogenesis often gives rise to intractable immune escape and prognosis recurrence. Thus, a valid systematic approach based on big data mining and genome-wide RNA-seq data is imperative to further investigate the pathogenetic mechanism and identify biomarkers for drug design. In this study, systems biology method was applied to trim false positives from the host/pathogen genetic and epigenetic interaction network (HPI-GEN) under HBV infection by two-side RNA-seq data. Then, via the principal network projection (PNP) approach and the annotation of KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, significant biomarkers related to cellular dysfunctions were identified from the core cross-talk signaling pathways as drug targets. Further, based on the pre-trained deep learning-based drug-target interaction (DTI) model and the validated pharmacological properties from databases, i.e., drug regulation ability, toxicity, and sensitivity, a combination of promising multi-target drugs was designed as a multiple-molecule drug to create more possibility for the treatment of HBV infection. Therefore, with the proposed systems medicine discovery and repositioning procedure, we not only shed light on the etiologic mechanism during HBV infection but also efficiently provided a potential drug combination for therapeutic treatment of Hepatitis B.

Present and Future Therapies for Chronic Hepatitis B

Chronic hepatitis B (CHB) remains the leading cause of liver-related morbidity and mortality across the world. If left untreated, approximately one-third of these patients will progress to severe end-stage liver diseases including liver failure, cirrhosis, and hepatocellular carcinoma (HCC). High level of serum HBV DNA is strongly associated with the development of liver failure, cirrhosis, and HCC. Therefore, antiviral therapy is crucial for the clinical management of CHB. Current antiviral drugs including nucleoside/nucleotide analogues (NAs) and interferon-α (IFN-α) can suppress HBV replication and reduce the progression of liver disease, thus improving the long-term outcomes of CHB patients. This chapter will discuss the standard and optimization antiviral therapies in treatment-naïve and treatment-experienced patients, as well as in the special populations. The up-to-date advances in the development of new anti-HBV agents will be also discussed. With the combination of the current antiviral drugs and the newly developed antiviral agents targeting the different steps of the viral life cycle or the newly developed agents modulating the host immune responses, the ultimate eradication of HBV will be achieved in the future.

Unmet need in chronic hepatitis B management

Despite all these exciting developments, there remain some unmet needs in the management for patients with chronic hepatitis B (CHB). As majority of CHB patients are going to use oral nucleos(t)ide analogues (NAs) for decades, Safety profile of NAs is of no doubt an important issue. The newest nucleotide analogue tenofovir alafenamide is potent in terms of viral suppression, together with favourable renal and bone safety profile. Biochemical response as reflected by alanine aminotransferase (ALT) normalization is recently found to be prognostically important. Patients who achieved ALT normalization have reduced the risk of hepatic events by 49%. Functional cure as reflected by hepatitis B surface antigen seroclearance not only implies patients may stop NA treatment, it also confers to a reduced risk of hepatocellular carcinoma and other hepatic events. Hence functional cure should be the ultimate treatment goal in CHB patients. Preemptive antiviral treatment may reduce mother-to-child transmission of hepatitis B virus, especially if birth dose of vaccination cannot be given in the first two hours after delivery. Lastly, despite the currently first-line NAs have high-genetic barrier to drug resistance mutations, there are still are many patients who were previously treated with low barrier of resistance including lamivudine, telbivudine or adefovir dipivoxil which could lead to antiviral resistance and affecting the choice of NAs.

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

Aim

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

Methods

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

Results

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

Conclusions

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

Synthesis of an Anti-hepatitis B Agent, 2'-Fluoro-6'-methylene-carbocyclic Adenosine (FMCA) and Its Phosphoramidate (FMCAP)

2'-Fluoro-6'-methylene-carbocyclic adenosine (FMCA, 12) and its phosphoramidate prodrug (FMCAP, 14) have been proven as a potential anti-HBV agent against both adefovir-resistant as well as lamivudine-resistant double (rtL180M/rtM204V) mutants. Furthermore, in vitro, these agents have demonstrated significant activity against lamivudine/entecavir triple mutants (L180M + S202G + M204V). These preliminary results encourage us for further biological evaluation of FMCA and FMCAP to develop as a potential clinical candidate as an anti-HBV agent, which may overcome the problem of drug resistance in HBV therapy. To support the preclinical exploration, a scalable synthesis of this molecule was needed. In this communication, a practical and scalable synthesis of FMCA, and its prodrug, is reported via ketone 1. The selective opening of the isopropylidene group of 2 led to compound 3. Protection of the allylic hydroxyl group of 3, followed by fluorination and deprotection, afforded the key intermediate 10, which was condensed with a Boc-protected adenine, followed by deprotection, furnished the target nucleoside FMCA (12) in high yield. Further coupling of phosphorochloridate of L-alanine isopropyl ester (13) with FMCA gave its phosphoramidate prodrug FMCAP (14) in good yield.

Taiwan consensus statement on the management of chronic hepatitis B

The experts of Taiwan Association for the Study of Liver (TASL) have actively participated and led the guidelines on hepatitis B virus (HBV) management by Asian Pacific Association for the Study of Liver (APASL) which is the first international association for the study of liver to publish the statement on HBV management before. However, there are more and more new data on the natural history and treatment of HBV infection in the past decade. These include new application of an old biomarker (quantitative HBsAg), clinical significance of HBV genotype and naturally occurring mutations, the role of non-invasive examination in evaluating severity of hepatic fibrosis, clinical significance of outcome calculators, new drug or new combination strategies towards more effective therapy and organ transplantation including liver and non-liver transplantation. It is time to publish the guidelines on HBV management of Taiwan. Hence, TASL have conducted an expert meeting to review, to discuss and to debate the relevant literatures, followed by draft the manuscript of HBV management guidelines and recommendations. The guidelines include general management, indications for fibrosis assessment, time to start or stop drug therapy, choice of drug to initiate therapy, when and how to monitor the patients during and after stopping drug therapy. Recommendations on the therapy of patients in special circumstances, including women in childbearing age, patients with antiviral drug resistance, concurrent viral infection, hepatic decompensation, patient receiving immune suppression or chemotherapy and patients in the setting of liver transplantation and hepatocellular carcinoma, are also included.

Differential Effect of HCV Eradication and Fibrosis Grade on Hepatocellular Carcinoma and All-cause Mortality

Whether a sustained virological response (SVR) improves long-term outcomes in chronic hepatitis C patients with earlier-stage fibrosis has not been established. We investigated the differential effect of SVR on the risk of outcomes according to hepatic fibrosis grade. Fibrosis grade was categorised using FIB-4: <1.45, low-probability of significant fibrosis; 1.45-3.25, intermediate-probability; and ≥3.25, high-probability. Primary and secondary endpoints were hepatocellular carcinoma (HCC) occurrence and death, respectively. Among 1,373 included chronic hepatitis C patients, 744 patients were treated with interferon-based or -free regimens and 622 (83.6%) achieved SVR. SVR was independently associated with lower risk of HCC (vs. untreated: adjusted hazard ratio [aHR], 0.165; 95% confidence interval [CI], 0.077-0.350; P < 0.001) and overall death (vs. untreated; aHR, 0.146; 95% CI, 0.050-0.424; P < 0.001) during the median observation of 3.5 (interquartile range, 1.9-6.6) years. The SVR group had significantly lower risk of HCC than the untreated group among patients with intermediate-probability (n = 492: aHR, 0.171; 95% CI, 0.051-0.578; P = 0.004) and high-probability (n = 446: aHR, 0.243; 95% CI, 0.107-0.551; P < 0.001) of significant fibrosis. HRs were maintained after balancing with inverse probability weighting. SVR was associated with reduced risk of HCC development and all-cause mortality in patients with chronic hepatitis C.

Treatment Efficacy and Safety of Tenofovir-Based Therapy in Chronic Hepatitis B: A Real Life Cohort Study in Korea

Background & Aims

We evaluated the efficacy and safety of Tenofovir disoproxil fumarate (TDF)-based therapy in naïve and treatment-experienced chronic hepatitis B (CHB) patients for 96 weeks in Korean real life practice.

Methods

A total of 209 CHB patients with a prescription for TDF at the Seoul and Daejeon St. Mary’s hospitals were enrolled from December 2012 to October 2014. We compared the virological responses and evaluated the renal safety of treatment-naive and treatment-experienced patients.

Results

An overall complete virological response (CVR) was achieved in 80.4% and 84.6% of patients at weeks 48 and 96, respectively. In a subgroup analysis, CVR at week 96 was present in 88.4%, 75.0%, 75.5%, and 83.3% of participants in the lamivudine-resistant (LAM-R) group, adefovir-resistant (ADV-R) group, multidrug-resistant (MDR) group, and suboptimal response group, respectively. In a multivariate analysis, ADV-R, MDR, hepatitis B virus DNA, and hepatitis B e antigen were independent predictors for CVR. With regard to renal safety, diabetes mellitus, cirrhosis, and an initial low estimated glomerular filtration rate were independent factors affecting creatinine elevation (≥0.5 mg/dL). Moreover, two patients with DM and cirrhosis experienced TDF-related Fanconi syndrome.

Conclusions

TDF-based therapy demonstrated sustained viral suppression and favorable safety during a 2-year treatment period. The LAM-R and suboptimal response groups showed comparable efficacy to the naïve group, while the ADV-R and MDR groups were significantly associated with a low CVR. Close monitoring of renal safety should be mandatory when treating CHB patients receiving TDF, particularly those with DM and cirrhosis.

Tenofovir alafenamide demonstrates broad cross-genotype activity against wild-type HBV clinical isolates and maintains susceptibility to drug-resistant HBV isolates in vitro

Tenofovir alafenamide (TAF) is a novel prodrug of tenofovir (TFV). This study evaluated the antiviral activity of TAF against wild-type genotype A-H HBV clinical isolates as well as adefovir-resistant, lamivudine-resistant, and entecavir-resistant HBV isolates. Full length HBV genomes or the polymerase/reverse transcriptase (pol/RT) region from treatment-naïve patients infected with HBV genotypes A-H were amplified and cloned into an expression vector under the control of a CMV promoter. In addition, 11 drug resistant HBV constructs were created by site-directed mutagenesis of a full length genotype D construct. Activity of TAF was measured by transfection of each construct into HepG2 cells and assessment of HBV DNA levels following treatment across a range of TAF concentrations. TAF activity in vitro was similar against wild-type genotype A-H HBV clinical isolates. All lamivudine- and entecavir-resistant isolates and 4/5 adefovir-resistant isolates were found to be sensitive to inhibition by TAF in vitro as compared to the wild-type isolate. The adefovir-resistant isolate rtA181V + rtN236T exhibited low-level reduced susceptibility to TAF. TAF is similarly active in vitro against wild-type genotype A-H HBV clinical isolates. The TAF sensitivity results for all drug-resistant isolates are consistent with what has been observed with the parent drug TFV. The in vitro cell-based HBV phenotyping assay results support the use of TAF in treatment of HBV infected subjects with diverse HBV genotypes, in both treatment-naive and treatment-experienced HBV infected patients.

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.

Treatment of chronic hepatitis B with tenofovir

Tenofovir (TDF) is a potent hepatitis B virus (HBV) inhibitor with a high barrier to drug resistance, and it has been recommended as one of the first-line drugs to treat chronic hepatitis B (CHB). This paper reviews the recent advances in the treatment of CHB with TDF, especially in terms of its efficacy as first-line and second-line antiviral therapies as well as its role in the prevention of mother-to-child HBV transmission.

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.

Hepatitis B: treatment choice and monitoring for response and resistance

Despite effective preventive primary prevention with vaccination, many people remain infected with hepatitis B virus (HBV) and suffer from its complications. Effective treatments such as interferon-based regimens and oral nucleoside/nucleotides have been developed over the last 30 years, but they are not perfect. Each of the treatments has its own merits, but none can eradicate HBV from the host. As a result, regular monitoring of the response during treatment and after treatment is required. The choice and monitoring of selected treatments, new potential therapeutic agents, and treatment options for drug resistance are discussed in this review.

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.

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

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

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.

Efficacy of interferon for chronic hepatitis B in patients with nucleoside and nucleotide combination therapy failure

BACKGROUND AND AIM

In China, inappropriate therapies with nucleos(t)ide analogues (NA) have induced hepatitis B virus resistance, combination therapy with nucleoside and nucleotide (ComTNsNt) failure, or multi-drug resistant mutations. However, the efficacy of combination therapy with entecavir plus tenofovir for ComTNsNt failure is limited. In the current study, the regimens of interferon-α (IFN-α) therapy, switching from NAs to IFN-α, and subsequent re-treatment with IFN-α were applied to treat ComTNsNt failure. We further evaluated the efficacy of this therapy.

METHODS

Eleven patients with ComTNsNt failure were enrolled in this study. Nine subjects (9/11) received IFN-α switching therapy. Combination therapy with IFN-α and ComTNsNt was administered in the first 4 weeks. Then, ComTNsNt was discontinued at the end of Week 4, and IFN-α monotherapy was continued for 6 months. Two (2/11) patients discontinued ComTNsNt without receiving IFN-α treatment. All 11 patients received the first re-treatment of IFN-α when they experienced hepatitis relapses after the withdrawal of IFN-α or ComTNsNt. Six (6/11) patients received a second re-treatment of IFN-α. Follow up was conducted after IFN-α therapy in all 11 patients.

RESULTS

Two patients (2/9) receiving IFN-α switching therapy experienced alanine aminotransferase (ALT) flare. In contrast, the two patients without IFN-α switching therapy experienced ALT flare. Multiple re-treatments with IFN-α resulted in a sustained response.

CONCLUSIONS

Interferon-α switching therapy and IFN-α re-treatment might be applied for treatment of ComTNsNt failure. IFN-α switching therapy resulted in safe ComTNsNt cessation, and IFN-α re-treatment induced a sustained response of IFN-α in all patients. This IFN-α treatment is an optional treatment for ComTNsNt failure.

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.

Entecavir plus tenofovir versus entecavir plus adefovir in chronic hepatitis B patients with a suboptimal response to lamivudine and adefovir combination therapy

Background/Aims

We compared the efficacies of entecavir (ETV) plus tenofovir (TDF) and ETV plus adefovir (ADV) in chronic hepatitis B (CHB) patients with genotypic resistance to lamivudine (LAM) who showed a suboptimal response to LAM and ADV combination therapy.

Methods

We reviewed 63 CHB patients with genotypic resistance to LAM who showed a suboptimal response to LAM and ADV combination therapy. Among these patients, 30 were treated with ETV + ADV and 33 were treated with ETV + TDF for 12 months.

Results

The only baseline characteristic that differed significantly between the two groups was the ETV resistance profile. The rate of a virologic response [serum hepatitis B virus (HBV) DNA level of <20 IU/mL] was significant higher for ETV+TDF than for ETV+ADV over 12 months (57.6% vs. 23.3%, P=0.006, at 6 months; 84.8% vs. 26.7%, P<0.001, at 12 months). The probability of a virologic response was significantly increased in ETV+TDF (P<0.001, OR=54.78, 95% CI=7.15-419.54) and decreased in patients with higher baseline viral loads (P=0.001, OR=0.18, 95% CI=0.07-0.50) in multivariate analysis. No serious adverse event occurred during the study period.

Conclusions

In patients with CHB who showed a suboptimal response to LAM and ADV combination therapy, ETV+TDF was superior to ETV+ADV in achieving a virologic response regardless of the HBV resistance profile. Further large-scale and long-term follow-up prospective studies are needed to explain these results.

Comparable efficacy with entecavir monotherapy and tenofovir-entecavir combination in chronic hepatitis B patients

OBJECTIVES

The long-term goal for chronic hepatitis B patients is to maintain viral suppression in order to reduce disease progression risk. Because patients with previous treatment failure may have multiple viral resistance mutations, finding effective therapy is challenging. Because recent studies have shown that the combination of entecavir and tenofovir is effective in achieving virological response in many patients with prior treatment failure and multiple drug resistance mutations, we compared outcomes with this combination versus monotherapy.

METHODS

With a retrospective chart review we compared results in 35 patients with previous treatment failure treated with the entecavir-tenofovir combination to results in patients treated with entecavir monotherapy.

RESULTS

Although combination therapy resulted in significantly faster achievement of DNA negativity compared to entecavir monotherapy, the modest ten-week advantage is unlikely to be important for most patients since entecavir resistance develops extremely slowly. Significantly more patients on combination therapy experienced viral breakthroughs, most of which were attributed to non-adherence due to difficulties with the combination regimen.

CONCLUSIONS

Our findings of reasonably comparable efficacy over time in the combination and monotherapy arms combined with the increased costs and compliance issues related to combination therapy weigh in favor of entecavir monotherapy in patients with previous treatment failure. However, because our study was a retrospective analysis of a small patient population, it will be important to confirm these findings with a randomised, controlled trial that compares these treatment approaches in treatment-experienced patients.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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