Lamivudine-resistant chronic hepatitis B: an observational study on adefovir in monotherapy or in combination with lamivudine

Tenofovir disoproxil fumarate monotherapy is superior to entecavir-adefovir combination therapy in patients with suboptimal response to lamivudine-adefovir therapy for nucleoside-resistant HBV: a 96-week prospective multicentre trial

BACKGROUND

A complete virological response is closely related to the long-term outcome of patients with chronic hepatitis B and prevention of emerging HBV mutations. We aimed to evaluate the efficacy of tenofovir disoproxil fumarate (TDF) monotherapy compared to entecavir-adefovir dipivoxil (ETV-ADV) combination therapy in patients with suboptimal responses to long-term lamivudine-adefovir dipivoxil (LAM-ADV) therapy for nucleoside analogue-resistant chronic hepatitis B.

METHODS

Patients (n=60) were randomized to TDF monotherapy or ETV-ADV combination therapy for 96 weeks. All patients had the rt204I/V mutation and serum HBV DNA was measured (>60 IU/ml) during LAM-ADV therapy. The primary end point was a complete virological response (HBV DNA <20 IU/ml) at week 96.

RESULTS

The median duration of prior LAM-ADV rescue therapy was 43 (7-108) months. A complete virological response was achieved in 86.6% and 53.3% of patients in the TDF and ETV-ADV groups, respectively, at week 96 (P=0.005). Reduction in serum HBV DNA was significantly greater in the TDF group than in ETV-ADV group (-3.2 ±1.2 versus -2.6 ±1.2; P=0.01). Hepatitis B e antigen loss (22.2% versus 16.6%; P=0.731) and biochemical responses (76.7% versus 73.3%; P=0.766) were not different between the TDF and ETV-ADV groups. No newly emerged mutations were detected. Both therapies demonstrated favourable safety profiles.

CONCLUSIONS

TDF therapy achieved a better complete virological response than ETV-ADV therapy in chronic hepatitis B patients with suboptimal response to long-term LAM-ADV rescue therapy. (KCT0000627).

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

Background/Aims

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

Methods

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

Results

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

Conclusion

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

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.

Outcome of adefovir add-on lamivudine rescue therapy of up to 5 years in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND AND AIM

We investigated the long-term efficacy of adefovir add-on lamivudine rescue therapy in lamivudine-resistant chronic hepatitis B and the optimal cutoff hepatitis B virus (HBV) DNA level that predicts complete virological response (CVR) among patients without CVR after 1 year of treatment.

METHODS

We reviewed 167 lamivudine-resistant chronic hepatitis B patients who received adefovir add-on rescue therapy for up to 5 years. Multivariate analysis, area under the receiver operating characteristic curves, and Youden index were used.

RESULTS

Median age was 47.0 years; 112 patients were male. Median baseline HBV DNA level was 6.6 log10 IU/mL; hepatitis B e antigen was positive in 130 (77.4%) patients. Five-year CVR, alanine aminotransferase normalization, hepatitis B e antigen seroconversion, and adefovir resistance rates were 86.9%, 92.5%, 16.7%, and 6.0%, respectively. One-year HBV DNA level independently associated with CVR. Optimal cutoff HBV DNA level to predict CVR among patients who failed to achieve CVR at 1 year was 800 IU/mL (area under receiver operating characteristic curve 0.752; sensitivity 49.3%, specificity 93.5%). During the 5-year treatment, 92.1% of patients with favorable response (HBV DNA < 800 IU/mL at 1 year) achieved CVR; 45.6% achieved CVR among suboptimal responders (HBV DNA ≥ 800 IU/mL at 1 year) (P < 0.001).

CONCLUSION

Complete virological response or HBV DNA level < 800 IU/mL after 1 year adefovir add-on lamivudine rescue therapy can favorably predict CVR.

Antiviral efficacy of entecavir versus entecavir plus adefovir for hepatitis B virus rtA181V/T mutants alone

BACKGROUND/AIMS

Hepatitis B virus (HBV) rtA181V/T mutants developed by long-term nucleos(t) ide analogue therapy are known to present cross-resistance for other nucleos (t) ide analogues, except entecavir (ETV). Some studies reported that HBV rtA181V/T mutants could induce cross-resistance to ETV and showed incomplete response as well as persistence of HBV DNA, despite rescue therapy by ETV. This study aimed to investigate the antiviral efficacy of ETV monotherapy and ETV plus adefovir (ADV) as rescue therapy for HBV rtA181V/T single mutation.

PATIENTS AND METHODS

A total of 30 patients who received ETV alone (1.0 mg/day, n = 16) or ETV plus ADV (10.0 mg/day, n = 14) over 48 weeks between April 2008 and October 2011 were enrolled. Virological, biochemical, and serological response at 48 weeks of rescue therapy were investigated retrospectively.

RESULTS

No significant difference in baseline characteristics was observed between the ETV group and the ETV plus ADV group. Virological response showed complete response (62.5 vs. 42.9%), partial response (6.3 vs. 28.6%), non-response (25.0 vs. 28.6%), and virological breakthrough (6.3 vs. 0%) in the two groups, respectively. Virological response did not statistically differ between both groups (P = 0.278). No significant difference in the mean reduction of serum HBV DNA and biochemical response was observed between both groups (4.3 ± 2.9 vs. 4.1 ± 1.8 log 10 IU/ml; P = 0.294 and 88.9 vs. 100%; P = 1.000, respectively). In addition, no significant difference in HBeAg loss or seroconversion was observed between the two groups (26.7 vs. 28.6%; P = 1.000).

CONCLUSIONS

ETV monotherapy and ETV plus ADV therapy were clinically effective and comparable as rescue therapy for HBV rtA181V/T mutants alone.

Long-term outcomes and dynamics of mutants associated with lamivudine-adefovir rescue therapy in patients with lamivudine-resistant chronic hepatitis B

Background/Aims

To investigate the association between the baseline profiles and dynamics of hepatitis B virus (HBV) DNA polymerase gene mutations and the long-term virological response of lamivudine (LAM)-adefovir (ADV) combination therapy in patients with LAM-resistant chronic hepatitis B.

Methods

Seventy-five patients who received LAM-ADV combination therapy for more than 12 months were analyzed. Restriction fragment mass polymorphism assays were used to detect and monitor the dynamics of LAM- and ADV-resistant mutations.

Results

The median duration of LAM-ADV combination therapy was 26 months (range, 12 to 58 months). The baseline mutation profiles, rtM204I (p=0.992), rtM204I/V (p=0.177), and rtL180M (p=0.051), were not correlated with the cumulative virological response, and the baseline HBV DNA level (p=0.032) was the only independent predictive factor for cumulative virological response. Tests for LAM- and ADV-resistant mutations were performed in 12 suboptimal responders in weeks 48 and 96. The population of rtM204 mutants persisted or increased in 8 of 12 patients, and rtA181T mutants newly emerged as a minor population in four patients until 96 weeks. Nevertheless, the viral loads progressively decreased during rescue therapy, and these dynamics did not correlate with virological response.

Conclusions

The baseline profile and dynamics of LAM-resistant mutations during LAM-ADV combination therapy are not associated with a virological response.

Molecular diagnosis and treatment of drug-resistant hepatitis B virus

Oral antiviral agents have been developed in the last two decades for the treatment of chronic hepatitis B (CHB). However, antiviral resistance remains an important challenge for long-term CHB therapy. All of the clinically available oral antiviral agents are nucleoside or nucleotide analogues that target the activity of viral reverse transcriptase (RT), and all are reported to have resistant mutations. Since the hepatitis B virus (HBV) RT, like other viral polymerases, lacks proofreading activity, the emergence of drug-resistance occurs readily under selective pressure from the administration of antiviral agents. The molecular diagnosis of drug-resistant HBV is based on sequence variations, and current diagnostic methods include sequencing, restriction fragment polymorphism analysis, and hybridization. Here, we will discuss the currently available molecular diagnosis tools, in vitro phenotypic assays for validation of drug-resistant HBV, and treatment options for drug-resistant HBV.

The impact of the hepatitis B virus polymerase rtA181T mutation on replication and drug resistance is potentially affected by overlapping changes in surface gene

The emergence of drug-resistant hepatitis B virus (HBV) is a major problem for antiviral treatment in chronic hepatitis B infection. In this study, we analyzed the evolution of drug-resistant mutations and characterized the effects of the rtA181T and rtI233V mutations on viral replication and drug resistance. We performed a clonal analysis of the HBV polymerase gene from serum samples during viral breakthrough treated with antiviral agents. A series of mutant clones containing rtA181T and/or rtI233V mutations were constructed and determined the effect of these mutations on the replication ability and drug resistance. An in vitro study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. Compared to the rtA181T surface missense mutation (rtA181T/sW172S), the introduction of rtA181T surface nonsense mutation (rtA181T/sW172*) resulted in decreased viral replication and increased drug resistance. Complementation assay revealed that the truncated PreS1 is responsible for reduced replication of rtA181T/sW172* mutant. Moreover, the rtA181T/sW172* mutant exhibited a defect in viral particle secretion. The rtI233V mutation that emerged during adefovir therapy reduced viral replication and conferred resistance to adefovir. Our data suggest that the impact of the rtA181T mutation on replication and drug resistance differs based on the mutation status of the corresponding surface gene. The rtI233V mutation also affects replication ability and drug resistance. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation.

IMPORTANCE

The emergence of drug-resistant HBV that are no longer susceptible to nucleos(t)ide analogues is a major problem for antiviral treatment in chronic hepatitis B infection. Among drug-resistant mutations, the single rtA181T mutation is known to confer cross-resistance to antiviral drugs. This mutation causes intermediate or reduced susceptibility to tenofovir. Moreover, the clinical occurrence of the rtA181T mutation during antiviral therapy is also high. Our study revealed that the effect of the rtA181T mutation on viral replication and drug resistance is dependent on the mutations in the overlapping surface gene. This observation suggests the need for genotypic analysis of overlapping surface genes to manage antiviral drug resistance if clinical isolates harbor the rtA181T mutation. We believe that our study will not only extend the understanding of the drug resistance mechanism, but it will also ultimately provide new treatment options for patients with multidrug resistant HBV.

Partial virological response to adefovir add-on lamivudine rescue therapy in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND/AIMS

In patients with lamivudine (LAM)-resistant chronic hepatitis B (CHB) receiving adefovir (ADV) add-on LAM therapy, insufficient viral suppression or the appearance of additional ADV resistance has remained unresolved. This study determined the partial virological response (PVR) criteria to predict a virological response (VR) at week 96 in these patients.

METHODS

96 patients with LAM-resistant CHB (ADV add-on LAM therapy >2 years) were analyzed. For predicting VR at week 96, the area under the receiver operating characteristic curve values at different time points were compared to establish the optimal time point, and the maximal Youden index was calculated to determine the optimal cut-off hepatitis B virus (HBV) DNA level.

RESULTS

50 (52.1%) patients achieved VR at 2 years after ADV add-on LAM therapy. The optimal PVR criteria were determined to be HBV DNA 500 IU/ml at week 48. 44 (45.8%) patients who met optimal PVR criteria showed a significantly higher risk for detectable HBV DNA levels at week 96 than those with a favorable VR (HBV DNA <500 IU/ml) at week 48.

CONCLUSIONS

This study suggested optimal PVR criteria in patients with LAM-resistant CHB receiving ADV add-on LAM therapy. Modification of the antiviral agent regimen should be considered if the serum HBV DNA level exceeds 500 IU/ml at week 48.

Two rescue therapies in lamivudine-resistant patients with chronic hepatitis B in the central China: adefovir monotherapy and adefovir plus lamivudine

The emergence of mutations that confer drug resistance in patients with chronic hepatitis B (CHB) is increasing in China. We aimed to compare the cumulative efficacy and resistance of adefovir (ADV) monotherapy and ADV add-on lamivudine (LAM) (ADV+LAM) therapy in LAM-resistant patients. One-hundred adult CHB patients with LAM-resistance mutations were identified. Of these 100, 52 patients were treated with ADV monotherapy and 48 were treated with ADV+LAM combination therapy for at least 24 months. After 2-year treatment, the cumulative rates of serum alanine aminotransferase normalization were, respectively, 73.1 and 83.3 % in the ADV monotherapy and ADV+LAM therapy groups (P = 0.216). Additionally, 36 patients receiving ADV plus LAM had hepatitis B e antigen loss/seroconversion, as compared with 30 in patients (P = 0.068). More patients who received LAM plus ADV than those who received ADV alone had HBV DNA levels below 1,000 international unit/milliliters (83.3 vs. 50 %, P < 0.001). Viral breakthrough and genotypic mutations were detected in 19 (36.5 %) and 9 (18.8 %) patients in the ADV monotherapy and ADV+LAM therapy groups, respectively (P = 0.048). ADV+LAM combination therapy demonstrated faster and significantly greater suppression of HBV DNA compared with ADV therapy alone for patients with LAM-resistance mutations. ADV+LAM was superior to ADV monotherapy in achieving the initial viral breakthrough and genotypic mutations. ADV+LAM combination therapy was rational for most of LAM-resistant Chinese patients with chronic hepatitis B.

Entecavir plus adefovir combination treatment for chronic hepatitis B patients after failure of nucleoside/nucleotide analogues

BACKGROUND

The combination of entecavir, a nucleoside analogue, and adefovir, a nucleotide analogue, would be a promising salvage treatment for chronic hepatitis B (CHB) patients who fail nucleoside/nucleotide analogue (NA) regimens.

METHODS

A total of 89 CHB patients who had failed NA regimens and were treated with entecavir plus adefovir combination for at least 12 months were included.

RESULTS

Mean baseline HBV DNA of patients was 6.16 ±1.44 log(10) IU/ml. Patients were classed by the number of previously failed NAs; 1 NA (lamivudine; n=15; Group 1), 2 NAs (lamivudine and either adefovir or entecavir; n=39; Group 2) and 3 NAs (lamivudine, adefovir and entecavir; n=35; Group 3). After 12 months of treatment, the mean reduction in HBV DNA was greater in Group 1 than in Group 2 or 3 (-5.81 ±1.71, -3.20 ±1.36 and -2.93 ±1.56 log(10) IU/ml, respectively; P<0.01). The rates of virological response (HBV DNA<2,000 IU/ml) were 100%, 79.5% and 34.3% (P<0.01), and the rates of complete virological response (HBV DNA<60 IU/ml) were 53.3%, 25.6% and 14.3% in Group 1, 2 and 3, respectively (P<0.01) at 12 months. Higher baseline HBV DNA (odds ratio =0.59; P=0.02) and increasing number of previously failed NAs (P<0.01) were independently associated with a lower rate of complete virological response at 12 months.

CONCLUSIONS

Entecavir plus adefovir combination treatment was effective in achieving virological response in CHB patients after failure of NAs. However, its effect progressively decreased as the number of previously failed NAs increased.

Virologic responses to add-on adefovir dipivoxil treatment versus entecavir monotherapy in children with lamivudine-resistant chronic hepatitis B

PURPOSE

The aim of the study was to compare the virologic response to adefovir (ADV) add-on therapy with switching to entecavir (ETV) monotherapy in children and adolescents with chronic hepatitis B (CHB) who have developed lamivudine (LAM) resistance during LAM treatment.

METHODS

Twenty-seven consecutive patients with CHB who had developed LAM resistance during LAM treatment were included. Of these 27 patients, 8 patients were treated with the addition of ADV to ongoing LAM and 8 patients were treated by switching to ETV monotherapy and each of these 16 patients were compared with the 11 patients who were treated by switching to ADV alone, as a historical control. Therapeutic responses to treatment were evaluated at 12, 24, 36, and 48 weeks from the initiation of therapy by measuring the decrement of hepatitis B virus (HBV)-DNA titers.

RESULTS

The therapeutic period for HBV-DNA titer decrement (>2  log(10) IU/mL) was significantly shorter in both the LAM+ADV group and the ETV group than in the ADV group (P = 0.008); however, there was no significant difference between the LAM+ADV group and the ETV group. The rate of virologic response, defined as decrement in HBV-DNA titer to undetectable levels at 24 weeks, was significantly higher in both the LAM+ADV group and the ETV group than in the ADV group (P = 0.029).

CONCLUSIONS

Both the LAM+ADV combination therapy and ETV monotherapy exhibited significantly more effective virologic responses compared to the ADV monotherapy in children and adolescents with LAM-resistant CHB, although there was no significant difference between the LAM+ADV group and the ETV group.

A pilot randomized controlled trial of dual-plasmid HBV DNA vaccine mediated by in vivo electroporation in chronic hepatitis B patients under lamivudine chemotherapy

A DNA vaccine against the hepatitis B virus (HBV), enhanced by IL-2/IFN-γ fusion protein expression from a plasmid construct and mediated by in vivo electroporation, was evaluated in a total of 39 HBeAg-positive patients with chronic hepatitis B (CHB). The six of 39 patients with a serum alanine aminotransferase (ALT) value of 1-2 times upper limit of normal (ULN) were assigned to the open-label arm (Group01) receiving vaccine monotherapy; the remaining 33 patients with an ALT of more than two times ULN were enroled to the randomized and controlled arm (Group02) receiving lamivudine (LAM) monotherapy (LAM+placebo) or combined therapy (LAM+DNA vaccine) in 1:2 ratio. In Group01, a significant elevation of HBV-specific IFN-γ-secreting T-cell counts in comparison with baseline was observed. In Group02, the proportion of patients with HBV DNA suppression was higher with LAM+DNA vaccine than with LAM monotherapy at each visit time point after the final injection of DNA vaccine at week 36, revealing a significant difference between the two groups (P = 0.03) at week 60. The incidence of dual-site mutations of rtM204/I/S+rtL180M was significantly lower (P = 0.03) with an identified lower virological breakthrough (VBT) rate (P = 0.03) in patients receiving LAM+DNA vaccine than LAM monotherapy, accompanied with a significant higher positive T-cell response rate in patients receiving LAM+DNA vaccine (P = 0.03). In conclusion, this study provides evidence that HBV DNA vaccination is safe and immunologically effective, and that the HBV-specific T-cell responses induced by DNA vaccination under LAM chemotherapy showed a correlation with the suppression of viral replication in patients with CHB.

KASL Clinical Practice Guidelines: Management of chronic hepatitis B

The guideline on the management of chronic hepatitis B (CHB) was first developed in 2004 and revised in 2007 by the Korean Association for the Study of the Liver (KASL). Since then there have been many developments, including the introduction of new antiviral agents and the publications of many novel research results from both Korea and other countries. In particular, a large amount of knowledge on antiviral resistance--which is a serious issue in Korea--has accumulated, which has led to new strategies being suggested. This prompted the new guideline discussed herein to be developed based on recent evidence and expert opinion.

TARGET POPULATION

The main targets of this guideline comprise patients who are newly diagnosed with CHB and those who are followed or treated for known CHB. This guideline is also intended to provide guidance for the management of patients under the following special circumstances: malignancy, transplantation, dialysis, coinfection with other viruses, pregnancy, and children.

Virologic response is not durable after adefovir discontinuation in lamivudine-resistant chronic hepatitis B patients

Background/Aims

We investigated the durability of the biochemical and virologic responses after adefovir (ADV) discontinuation in lamivudine-resistant (LMV-R) chronic hepatitis B (CHB) patients, and the outcomes of ADV discontinuation compared to that of ADV maintenance.

Methods

The indication for ADV treatment cessation was an undetectable level of hepatitis B virus (HBV) DNA documented on two occasions at least 6 months apart. All patients received additional ADV for at least 12 months after the confirmation of undetectable HBV DNA (Cobas TaqMan PCR assay, <70 copies/mL). Of 36 patients who had a sufficient ADV therapeutic effect, 19 discontinued ADV treatment, while the others maintained it. A virologic rebound was arbitrarily defined as the redetection of HBV DNA at a level higher than 10⁵ copies/mL.

Results

In the ADV discontinuation group, ADV treatment and additional therapy were administered for medians of 33 months (range, 12-47 months) and 18 months, respectively. The patients were followed for a median of 12 months (range, 3-30 months) after ADV cessation. During that period, 18 of 19 patients (95%) experienced viral relapse. Viral rebound was observed in six patients (32%). However, 12 of 18 patients (67%) exhibited serum HBV DNA levels of less than 10⁵ copies/mL. Biochemical relapses were observed in four of the six patients with viral rebound. In the ADV maintenance group, patients were treated for a median of 53 months (range, 31-85 months), and 9 patients (53%) experienced viral breakthrough.

Conclusions

During short-term follow-up after ADV discontinuation, most patients (95%) exhibited viral relapse, whereas and viral breakthrough occurred in about half of patients (53%) maintained on ADV therapy. Therefore, the durability of virologic response after ADV discontinuation in LMV-R patients was unsatisfactory. In addition, and viral breakthrough was not infrequent in the ADV continuation group.

High dose lamivudine in HBV-related cirrhotic patients with unsatisfactory response after adefovir add-on

BACKGROUND

Before tenofovir approval for chronic hepatitis B therapy, the clinical management of patients with suboptimal response or virological breakthrough during combination treatment with lamivudine and adefovir dipivoxil was a difficult clinical challenge.

AIMS

In order to improve virologic response and reduce the risk of decompensation, we evaluate the efficacy of a high dose of lamivudine on chronic HBV patients who have previously presented an unsatisfactory response during treatment with lamivudine 100mg/day and adefovir 10mg/day.

METHODS

Six patients with HBV-related liver cirrhosis were prospectively enrolled. All were HBeAg-negative and presented a suboptimal response or virological breakthrough after "adefovir add-on" because of development of clinical breakthrough during Lamivudine treatment. Lamivudine dose was increased to 200 or 300 mg, depending on viral load. After 12 months of follow-up, virological and biochemical response were evaluated.

RESULTS

After 12 months of high-dose lamivudine, all patients (6/6, 100%) achieved a significant decrease of serum HBV DNA (mean reduction 2,62 ± 1,15 Log10 UI/ml, P = 0.03) and normalized ALT. In three patients (3/6, 50%), HBV DNA became undetectable within 6 months. No patient developed liver decompensation and no significant changes occurred in serum creatinine, serum and urinary electrolytes. No adverse events were registered.

CONCLUSIONS

In our experience, rescue strategy with high-dose lamivudine inhibited viral replication leading to undetectability of serum HBVDNA. This rescue treatment presented a good safety profile, without adverse events during the study period. Customized increase of nucleos(t)ide analogues dose in difficult-to-treat patients may be a proficient approach in challenging clinical setting.

Comparative meta-analysis of adefovir dipivoxil monotherapy and combination therapy of adefovir dipivoxil and lamivudine for lamivudine-resistant chronic hepatitis B

OBJECTIVES

The aim of the current study was to compare the effectiveness of adefovir dipivoxil (ADV) monotherapy with that of combination ADV and lamivudine (LAM) therapy in the treatment of LAM-resistant chronic hepatitis B (CHB).

METHODS

Publications on the effectiveness of ADV monotherapy versus the combination of ADV and LAM therapy for the treatment of LAM-resistant CHB were identified by a search (up to year 2010) of the PubMed, HealthStar, ScienceDirect, and VIP databases. Biochemical response data (alanine aminotransferase normalization rate) and virological response data (serum hepatitis B virus DNA undetectable rate) were extracted and combined to obtain an integrated result.

RESULTS

The literature search yielded 11 articles, six of which reported randomized controlled trials; the remaining five reported prospective cohort studies. The summary odds ratio (OR) values of the biochemical response at 3, 6, 12, and >12 months were 1.60 (p=0.06), 1.30 (p=0.18), 1.77 (p=0.008), and 3.35 (p<0.00001), respectively. The summary OR values of the virological response at 3, 6, 12, and >12 months were 1.46 (p=0.21), 1.68 (p=0.04), 1.16 (p=0.54), and 1.87 (p=0.01), respectively.

CONCLUSIONS

The effectiveness of the combination therapy was not obviously predominant over the monotherapy in short duration therapies; however, the combination therapy had a great advantage over monotherapy in both biochemical and virological response when the therapy duration was prolonged to >12 months.

High rate of complete viral suppression with combination therapy in patients with chronic hepatitis B and prior treatment failure

BACKGROUND

Combination therapy for chronic hepatitis B virus (HBV) infection is recommended for patients with antiviral resistance (AVR) or partial response (PR) to earlier antiviral therapy; however, data on outcomes are limited.

GOALS

To determine the rate of complete viral suppression (CVS) with combination therapy and to compare CVS among different indications and treatment regimens.

METHODS

A cohort of 109 consecutive patients with chronic hepatitis B from 3 liver clinics in Northern California was retrospectively studied. All patients started combination therapy between April 2004 and August 2009 for the following indications: AVR (n = 29), PR (n = 60), or others (n = 20). Combination treatments included lamivudine (LAM), adefovir (ADV), telbivudine (LdT), entecavir (ETV), tenofovir (TDF), and emtricitabine (FTC). CVS was defined as undetectable serum HBV DNA <100 IU/mL.

RESULTS

Among the patients, who were nearly all Asian (99%), 73% had ≥ 2 prior treatments and 82% had treatment failure (AVR or PR). Median treatment duration of combination therapy was 21 months (range, 6 to 50 mo). The majority (77%) achieved CVS after 6 months of various combination regimens: 80% for ETV+TDF, 76% for TDF+LAM or FTC or LdT, 75% for ETV+ADV, and 69% for ADV+LAM or LdT (P = 0.86). After 6 months of therapy, CVS was observed in a similar proportion of patients treated for PR and AVR (72% and 74%, respectively).

CONCLUSIONS

Although the majority of 109 treatment-experienced patients had prior treatment failure, high rates of CVS were rapidly achieved and did not significantly differ between indications of AVR and PR or between ETV-based and TDF-based regimens.

Lamivudine plus adefovir combination therapy versus entecavir monotherapy for lamivudine-resistant chronic hepatitis B: a systematic review and meta-analysis

Background

Chronic hepatitis B virus (HBV) infection represents a serious global health problem and resistance to lamivudine (LAM) has become a serious clinical challenge. Previous rescue therapy for the treatment of chronic LAM-resistant hepatitis B infected patients included switching to entecavir (ETV) and adding adefovir (ADV) or tenofovir (TFV). At present, switching to ETV is not recommended for rescue therapy for LAM-resistant chronic hepatitis B (CHB). The aim of this report was to determine whether add-on ADV was a superior rescue strategy in the treatment of CHB patients with LAM resistance.

Methods

We searched Medline/PubMed, EMBASE, Web of Knowledge, and the Cochrane Library. Relative risks (RRs) of virologic response, virologic breakthrough, normalization of serum alanine aminotransferase (ALT) levels and HBeAg seroconversion rates were studied. Factors predicting virologic response, standardized mean differences (SMD) in HBV DNA levels and safety were reviewed.

Results

Six eligible trials (451 patients in total) were included in the analysis. The rate of virologic breakthrough in the ETV group was higher than that in the LAM plus ADV group. There were no statistical differences in virologic response, ALT normalization and HBeAg seroconversion in either group 48 weeks post treatment. LAM plus ADV combination therapy produced faster and greater HBV DNA reduction rates 24 weeks post therapy compared to ETV monotherapy. HBV DNA baseline levels and the initial virologic response (IVR) were predictive of the virologic response. Additionally, combination therapy or monotherapy were both well tolerated.

Conclusions

LAM plus ADV combination therapy was more effective and produced longer-lasting effects than switching to ETV monotherapy in treating CHB patients with LAM resistance. However, considering the practical benefits and limitations of ADV, individualized therapy will be needed in patients with prior history of LAM resistant infections.

Treatment of chronic hepatitis B: update of the recommendations from the 2007 Italian Workshop

The Italian recommendations for the therapy of hepatitis B virus (HBV)-related disease were issued in 2008. Subsequently in 2008 the nucleotide analogue (NA) Tenofovir was approved for antiviral treatment. The introduction of this important new drug has called for the current guidelines update, which includes some additional revisions: (a) the indication for therapy is extended to mild liver fibrosis and the indication for treatment is graded as "possible", "optional" or "mandatory" according to the fibrosis stage; (b) two different treatment strategies are described: first line definite duration treatment with interferon, long-term treatment of indefinite duration with NA; (c) the indication to follow either strategy is also based on the stage of liver fibrosis; (d) virological monitoring is modified to include the definitions of failure and of sustained virological response to interferon therapy; (e) the recommendation to use HBV DNA assays with high sensitivity and wide linear ranges is underlined (f) guidelines on post-treatment follow-up after finite treatment with NA, potential side effects of therapy and non-virological monitoring are defined; (g) definitions and treatment of patients without optimal response to NA are reported; (f) treatment and monitoring of compensated or decompensated cirrhosis and hepatocellular carcinoma are updated.

[Analogs combination therapy in chronic hepatitis B: when and how?]

Hepatitis B virus (HBV) genomic variability is responsible for the complexity of the viral quasi-species and its evolution during the course of infection. The persistence of infected cells promotes the selection of drug-resistant strains. The development of nucleoside analogs without cross-resistance has provided a rationale for combination therapy. De novo combination, with low genetic barrier drugs, prevents the emergence of resistance in the short-term for drugs with a low genetic barrier and improves the control of infection. Long-term studies are needed to determine whether de novo combination is beneficial for analogs with a high genetic barrier as well. The add-on strategy is a standard in case of emergence of resistant mutants. This strategy needs to be implemented as early as possible before the virological breakthrough, especially if the viral suppression is sub-optimal. Clinical trials are mandatory in order to assess whether a) de novo combination is better than an early add-on strategy; and b) whether in case of sub-optimal viral suppression, an early add-on strategy is better in the long-term than a switch to a more potent drug with a high genetic barrier.

Four-year study of lamivudine and adefovir combination therapy in lamivudine-resistant hepatitis B patients: influence of hepatitis B virus genotype and resistance mutation pattern

To investigate the efficacy of long-term lamivudine (3TC) and adefovir dipivoxil (ADV) combination therapy in 3TC-resistant chronic hepatitis B virus (HBV) infected patients, we analysed 28 3TC-resistant patients treated with the combination therapy during 47 months (range, 9-75). At 12, 24, 36, and 48 months, the rates of virological response with undetectable HBV DNA (≤ 2.6 log copies/mL) were 56, 80, 86, and 92%, respectively. Among 17 hepatitis B e antigen (HBeAg)-positive patients, HBeAg disappeared in 24% at 12 months, 25% at 24 months, 62% at 36 months, and 88% at 48 months. When HBV genotypes were compared, patients with genotype B achieved virological response significantly more rapidly than those with genotype C (P=0.0496). One patient developed virological breakthrough after 54 months, and sequence analysis of HBV obtained from the patient was performed. An rtA200V mutation was present in the majority of HBV clones, in addition to the 3TC-resistant mutations of rtL180M+M204V. The rtN236T ADV-resistant mutation was observed in only 25% clones. In vitro analysis showed that the rtA200V mutation recovered the impaired replication capacity of the clone with the rtL180M+M204V mutations and induced resistance to ADV. Moreover, rtT184S and rtS202C, which are known entecavir-resistant mutations, emerged in some rtL180M+M204V clones without rtA200V or rtN236T. In conclusion, 3TC+ADV combination therapy was effective for most 3TC-resistant patients, especially with genotype B HBV, but the risk of emergence of multiple drug-resistant strains with long-term therapy should be considered. The mutation rtA200V with rtL180M+M204V may be sufficient for failure of 3TC+ADV therapy.

Efficacy of adefovir add-on lamivudine rescue therapy compared with switching to entecavir monotherapy in patients with lamivudine-resistant chronic hepatitis B

No study has reported on the comparative effect of adefovir (ADV) add-on lamivudine (LAM) versus switching to entecavir (ETV) in LAM-resistant patients with chronic hepatitis B. From October 2007 to September 2008, 92 consecutive LAM-resistant patients were enrolled (47 LAM+ADV and 45 ETV 1 mg). All patients were followed for at least 12 months. The parameters assessed included normalization of ALT, HBeAg seroconversion, undetectable HBV DNA, reduction of HBV DNA, and predictors of virologic response. In the LAM+ADV and ETV groups, the baseline DNA levels were 7.61 (5.19-9.49) and 7.10 (5.43-9.74)log(10)copies/ml, respectively. At month 12, a virologic response occurred in 18/47 (38.3%) and 11/45 (24.4%; P=0.182) patients; ALT normalization, in 39/41 (95.1%) and 36/40 (90.0%; P=0.432); HBeAg seroconversion, in 5.1% and 2.4% (P=0.606); and virologic breakthrough, in 2.1% and 11.1% (P=0.107), respectively. The mean reduction from the baseline HBV DNA level was greater in the LAM+ADV group at month 12 (3.80 ± 1.12 vs. 2.7 ± 1.32 log(10)copies/ml; P<0.001). In the multivariate analysis, the independent parameters related to a virologic response at month 12 were baseline ALT (OR=1.003, 95% CI=1.000-1.006, P=0.026) and baseline HBV DNA (OR=0.495, 95% CI=0.298-0.823, P=0.007). Compared with switching to ETV monotherapy, ADV add-on LAM therapy was more effective at reducing the viral load in patients with LAM resistance, and the baseline HBV DNA and ALT levels were independent predictors of the virologic response. However, ADV add-on therapy had limitations in patients with a higher baseline HBV DNA in LAM rescue therapy.

Lamivudine plus adefovir or entecavir for patients with chronic hepatitis B resistant to lamivudine and adefovir

BACKGROUND & AIMS

Little is known about the optimal management of patients with chronic hepatitis B (CHB) who developed multiple-drug resistance.

METHODS

We assessed 91 patients with compensated CHB who developed adefovir-resistant mutations during adefovir monotherapy for lamivudine-resistant CHB. Of these, 41 were treated with a combination of lamivudine plus adefovir (LAM+ADV group) and 50 were treated with entecavir monotherapy (ETV group).

RESULTS

There were no significant differences between the two groups in baseline characteristics, including serum HBV DNA levels (p>0.05). The rate of virologic non-response (HBV DNA reduction <1 log(10) IU/ml at 6 months) was significantly greater in the LAM+ADV than in the ETV group (51.2% vs. 16.0%, p<0.01). At 12 months, HBV DNA declined less in the LAM+ADV than in the ETV group (-1.49+/-1.78 vs. -3.47+/-2.13 log(10) IU/ml, p<0.01). Only 12.2% and 22.0% of patients in the LAM+ADV and ETV groups, respectively, achieved complete virologic response (HBV DNA <60 IU/ml) at 12 months. Multivariable analysis showed that LAM+ADV group (OR=0.08, CI=0.02-0.28) and the presence of the rtA181V/T mutation (OR=0.21, CI=0.05-0.91) were independently associated with a decreased rate of virologic response (HBV DNA <2000 IU/ml) at 12 months.

CONCLUSIONS

In patients with CHB resistant to lamivudine and adefovir, combination therapy with these two drugs was not effective and was inferior to entecavir monotherapy in suppressing HBV DNA. However, the response to entecavir monotherapy was also not optimal. These results emphasize the importance of preventing the development of multidrug-resistant HBV and of exploration for adequate combination therapy in treatment of multidrug-resistant CHB.

Question of ALT flare during switch to adefovir from lamivudine: A single center open-label, randomized, safety study (June 17, 2005 to February 5, 2009)

Earlier clinical studies have reported an ALT flare greater than 10 times the upper limit of normal in some patients with chronic hepatitis B when their lamivudine (LAM) treatment was switched to adefovir (ADV) therapy. The current study compared the safety of switching directly to ADV versus overlapping LAM and ADV for 3 months followed by ADV monotherapy. Patients with chronic hepatitis B receiving LAM therapy for > or = 6 months were eligible for the study regardless of the presence of LAM resistance, HBeAg status or serum ALT levels. Eighteen patients (13 males) were randomized to direct switch to ADV and 17 patients (10 males) to overlap. HBV-DNA, ALT, albumin, and total bilirubin were assayed at baseline, 3, 6, 9, and 12 months. Study drugs were discontinued at the end of 12 months with the follow up at 3 and 6 months. The decision to continue antiviral therapy was made at the discretion of the investigator. Baseline ALT levels were similar between the direct switch and overlap group: median ALT (U/L) was 44.0 (16-266) and 33.0 (19-367) for direct switch for overlap group, respectively (P = 0.42). No ALT flare was noted at 3 months in either group: median ALT decreased from 44.0 to 34.5 U/L in the direct switch group, and from 33.0 to 23.0 in the overlap group. Furthermore, no patient in either group exhibited ALT flare throughout the 12 months. This study did not show an ALT flare during switch to ADV at 3 months or at any time later.

Long-term adefovir dipivoxil monotherapy for up to 5 years in lamivudine-resistant chronic hepatitis B

BACKGROUND

Large clinical studies assessing long-term adefovir dipivoxil salvage monotherapy in patients with lamivudine-resistant chronic hepatitis B (CHB) are lacking, particularly in patients positive for hepatitis B e antigen (HBeAg). We assessed the efficacy and resistance profile of adefovir dipivoxil monotherapy for up to 5 years in a large cohort of Korean patients with lamivudine-resistant CHB.

METHODS

A total of 320 patients (81.3% HBeAg-positive; 100% genotype C) with confirmed genotypic lamivudine-resistant CHB were switched to adefovir dipivoxil 10 mg once daily. Liver function tests and HBV DNA were monitored every 3 months. Genotypic resistance to adefovir dipivoxil was performed in patients with detectable HBV DNA.

RESULTS

The overall cumulative virological response rate at 5 years of adefovir dipivoxil therapy was 48.8%. The virological response rate was significantly higher in HBeAg-negative patients (62.0% versus 45.9%; P=0.010). Most cases of virological response (131/134, 97.8%) occurred within the first 36 months of therapy. The 5-year cumulative probability of genotypic resistance and virological breakthrough was 65.6% and 61.8%, respectively. Predictive factors for a virological response included baseline HBeAg seronegativity, HBV DNA< or =8 log(10) copies/ml and achievement of an on-treatment initial virological response.

CONCLUSIONS

Adefovir dipivoxil salvage monotherapy for lamivudine-resistant CHB resulted in a modest cumulative virological response rate at 5 years, which was associated with progressive antiviral resistance. Consequently, adefovir monotherapy is not preferable as a first-line strategy for lamivudine resistance where combination lamivudine plus adefovir dipivoxil therapy is available.

Avoiding and managing lamivudine resistance in chronic hepatitis B: current approaches and potential strategies including pegylated interferon

Since its approval for the treatment of chronic hepatitis B in 1998, lamivudine (LAM) has been used extensively throughout the world, because of its relatively low costs and favourable tolerability. However, clinical trials and cohort studies have demonstrated that a high rate of resistance to this drug develops and, as a result, it is no longer included as a first-line therapy in most current treatment guidelines. Nevertheless, because of its low cost, this drug continues to be used in many countries and the pool of patients who have developed resistance to LAM continues to increase. Thus, there is a clear need to develop coherent management strategies to treat such patients as well as limit the emergence of resistance in the first instance. The purpose of this review is to highlight the need to aim for long-term treatment success while limiting the emergence of drug resistance and its consequences for the future. In addition to add-on/switch strategies with other nucleos(t)ide analogs, currently available data suggest that interferon-based therapies, with their potential to induce a sustained response, are worthy of consideration not only for reducing de novo resistance but as an option for the management of those patients in whom drug resistance has already developed.

Monotherapy versus combination therapy for the treatment of chronic hepatitis B

BACKGROUND

Nucleos(t)ide analogues, active against hepatitis B polymerase, suppress viral replication and improve clinical outcome. However, the emergence of drug-resistant mutants can result in treatment failure.

OBJECTIVES

We describe how the choice of first-line therapy is critical to long-term treatment success.

METHODS

A review of current drug therapies is provided.

RESULTS/CONCLUSIONS

Monotherapy with early-generation drugs (lamivudine or adefovir) was associated with a high rate of viral drug resistance and combination therapy with these agents was shown to reduce the incidence of resistance. The latest-generation drugs (entecavir and tenofovir) are potent inhibitors of viral replication and, in treatment-naive subjects, viral resistance to entecavir is uncommon and is not yet reported to tenofovir. Therefore, monotherapy with either entecavir or tenofovir is the current preferred option in treatment-naive patients. Combination therapy is appropriate in those with drug-resistant HBV infection, where drug choice is guided by the viral drug-resistance genotype/phenotype. Although combination therapy has been advocated in other patient groups (e.g., those with decompensated cirrhosis and following liver transplantation), there are, as yet, no data to mandate the use of combination therapy in such patients and any perceived benefit must be weighed against increased cost and risk for toxicity.

Meta-analysis: adefovir dipivoxil in combination with lamivudine in patients with lamivudine-resistant hepatitis B virus

Background

Currently, there are no conclusive results on the efficacy of adefovir dipivoxil (ADV) plus lamivudine (LAM) in LAM-resistant patients with chronic hepatitis B (CHB). The aim of study was to evaluate the efficacy of rescue therapy with ADV plus LAM compared to ADV monotherapy in LAM-resistant CHB patients.

Results

We searched PUBMED, EMBASE, Web of Science, CNKI (National Knowledge Infrastructure), VIP database, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews. Six eligible trials (442 patients in total) were included and evaluated for methodologic quality and heterogeneity. Greater virological response and lower emergence rate of ADV-associated mutants was observed in ADV plus LAM compared to ADV monotherapy (both P < 0.05). On the contrary, the rate of ALT normalization, HBeAg clearance and seroconversion were all similar between ADV plus LAM and ADV (all P > 0.05). Additionally, adding-on or switch-to ADV was both well tolerated.

Conclusion

The combination of ADV with LAM was superior in inhibiting HBV replication and preventing drug resistance as compared to ADV alone for LAM-resistant CHB patients.

Lamivudine and adefovir resistance in children and young adults with chronic hepatitis B

OBJECTIVE

Long-term lamivudine (LAM) and adefovir (ADV) treatment has been found to induce the emergence of drug-resistant hepatitis B virus (HBV) in a significant number of patients with chronic hepatitis B (CHB) infection. The aim of our study was to evaluate the LAM and ADV mutations detected in our patient group.

MATERIALS AND METHODS

Twenty-four patients diagnosed with CHB were enrolled in this study. The patient group consisted of those who had received 6 months of treatment with interferon-alpha and who did not response to this therapy. Patients were evaluated based on virologic and serologic response to therapy, and were classified as responders or non-responders. The treatment of non-responders continued with LAM (3mg/kg/d, maximum 100mg/d). Due to a lack of response to treatment, ADV (10mg/g) was added to the treatment regimen of eight young adult patients. The mutations associated with HBV drug resistance were investigated using reverse hybridization methods and PCR.

RESULTS

The mutation studies indicated that 14 (58.4%) of the patients had resistance. Three patients developed ADV-associated mutations (A181T), one after 18 months of ADV; the other two had undergone 18 and 36 months of LAM therapy without ADV exposure. Although the average LAM treatment period of the patients with LAM resistance was longer than for those in whom no resistance was detected, no statistically significant difference was found.

CONCLUSIONS

HBV treatment with nucleoside analogues results in the development of mutant strains, leading to drug resistance. Therefore genotypic resistance testing is important in planning and monitoring HBV treatment.

Adefovir dipivoxil resistance patterns in patients with lamivudine-resistant chronic hepatitis B

Background

Lamivudine (3TC)-resistant chronic hepatitis B patients demonstrated a higher rate of adefovir dipivoxil (ADV) resistance compared with nucleoside-naive patients. This study describes ADV mutation patterns in 3TC-resistant patients treated with ADV+3TC or ADV monotherapy, investigating whether mutations selected during 3TC therapy predispose to ADV resistance. Risk factors for ADV resistance were also evaluated.

Methods

A total of 60 3TC-experienced patients were treated with (or switched to) ADV monotherapy (30 patients) or ADV+3TC combination therapy (30 patients), and followed for at least 12 months. In all patients the hepatitis B virus reverse transcriptase (RT) region was amplified and directly sequenced before initiating ADV. The RT sequence was reevaluated for virological breakthrough patients and phenotypic analysis was performed for several patients.

Results

In total, 14 (23%) patients showed virological breakthrough (10/30 on ADV monotherapy and 4/30 on ADV+3TC). ADV resistance mutations (rtA181V/T and rtN236T) were detected alone or in combination for 11/14 patients, whereas novel substitutions were present in 3 patients. Before ADV treatment, apart from 3TC resistance signature mutations, additional changes were found, including the rtA181T mutation, which was already present in 2/14 ADV-resistant patients.

Conclusions

Although most patients showed virological breakthrough because of the well known rtA181V/T and rtN236T substitutions, more complex patterns were also found. ADV monotherapy, dose reduction and suboptimal virological response after 48 weeks of therapy were significantly associated with ADV resistance.

[Virologic response to adefovir dipivoxil monotherapy is not durable in HBeAg-positive, lamivudine-resistant chronic hepatitis B patients]

BACKGROUNDS/AIMS

It has been shown that adefovir dipivoxil is an effective antiviral agent in the treatment of chronic hepatitis B (CHB), not only in wild-type hepatitis B virus (HBV) infection, but also in lamivudine-resistant (LAMV-R) cases. However, little is known about the durability of the virologic response to adefovir in LAMV-R CHB patients.

METHODS

Fifteen HBV e-antigen (HBeAg)-positive, LAMV-R CHB patients showed a virologic response to adefovir monotherapy. These patients received additional adefovir for at least a further 12 months. The virologic relapse rate after discontinuation of adefovir was evaluated. In addition, predictive factors associated with virologic relapse were investigated.

RESULTS

The median level of serum HBV DNA before adefovir administration was 7,457,840 IU/mL (range 107,920-99,524,960 IU/mL). The median duration of adefovir treatment was 30 months (range 14-46 months). During a median follow-up period of 14 months after discontinuation of adefovir, the 1-, 2-, 3-, 6-, and 12-month cumulative relapse rates were 26.7%, 53.3%, 73.3%, 80%, and 80%, respectively. High pretreatment HBV DNA levels were found to be the only factor that was predictive of off-therapy relapse.

CONCLUSIONS

Our data suggest that the adefovir-monotherapy-induced virologic response is not durable in most patients with LAMV-R HBeAg-positive CHB, especially in those with a high pretreatment HBV DNA level.

Tenofovir disoproxil fumarate versus adefovir dipivoxil for chronic hepatitis B

BACKGROUND

Tenofovir disoproxil fumarate (DF) is a nucleotide analogue and a potent inhibitor of human immunodeficiency virus type 1 reverse transcriptase and hepatitis B virus (HBV) polymerase.

METHODS

In two double-blind, phase 3 studies, we randomly assigned patients with hepatitis B e antigen (HBeAg)-negative or HBeAg-positive chronic HBV infection to receive tenofovir DF or adefovir dipivoxil (ratio, 2:1) once daily for 48 weeks. The primary efficacy end point was a plasma HBV DNA level of less than 400 copies per milliliter (69 IU per milliliter) and histologic improvement (i.e., a reduction in the Knodell necroinflammation score of 2 or more points without worsening fibrosis) at week 48. Secondary end points included viral suppression (i.e., an HBV DNA level of <400 copies per milliliter), histologic improvement, serologic response, normalization of alanine aminotransferase levels, and development of resistance mutations.

RESULTS

At week 48, in both studies, a significantly higher proportion of patients receiving tenofovir DF than of those receiving adefovir dipivoxil had reached the primary end point (P<0.001). Viral suppression occurred in more HBeAg-negative patients receiving tenofovir DF than patients receiving adefovir dipivoxil (93% vs. 63%, P<0.001) and in more HBeAg-positive patients receiving tenofovir DF than patients receiving adefovir dipivoxil (76% vs. 13%, P<0.001). Significantly more HBeAg-positive patients treated with tenofovir DF than those treated with adefovir dipivoxil had normalized alanine aminotransferase levels (68% vs. 54%, P=0.03) and loss of hepatitis B surface antigen (3% vs. 0%, P=0.02). At week 48, amino acid substitutions within HBV DNA polymerase associated with phenotypic resistance to tenofovir DF or other drugs to treat HBV infection had not developed in any of the patients. Tenofovir DF produced a similar HBV DNA response in patients who had previously received lamivudine and in those who had not. The safety profile was similar for the two treatments in both studies.

CONCLUSIONS

Among patients with chronic HBV infection, tenofovir DF at a daily dose of 300 mg had superior antiviral efficacy with a similar safety profile as compared with adefovir dipivoxil at a daily dose of 10 mg through week 48. (ClinicalTrials.gov numbers, NCT00116805 and NCT00117676.)