Efficacy of adefovir-based combination therapy for patients with Lamivudine- and entecavir-resistant chronic hepatitis B virus infection

Efficacy and cost-effectiveness of antiviral regimens for entecavir-resistant hepatitis B: A systematic review and network meta-analysis

BACKGROUND

Chronic hepatitis B (CHB) patients who had exposed to lamivudine (LAM) and telbivudine (LdT) had high risk of developing entecavir (ETV)-resistance after long-term treatment. We aimed to conduct a systematic review and a network meta-analysis on the efficacy and cost-effectiveness on antiviral regimens in CHB patients with ETV-resistance.

DATA SOURCES

We searched PubMed, EMBASE and Web of Science for studies on nucleos(t)ide analogues (NAs) treatment [including tenofovir disoproxil fumarate (TDF)-based rescue therapies, adefovir (ADV)-based rescue therapies and double-dose ETV therapy] in CHB patients with ETV-resistance. The network meta-analysis was conducted for 1-year complete virological response (CVR) and biological response (BR) rates using GeMTC and ADDIS. A cost-effective analysis was conducted to select an economic and effective treatment regimen based on the 1-year CVR rate.

RESULTS

A total of 6 studies were finally included in this analysis. The antiviral efficacy was estimated. On network meta-analysis, the 1-year CVR rate in ETV-TDF [odds ratio (OR)  = 22.30; 95 % confidence interval (CI): 2.78-241.93], LAM-TDF (OR  = 70.67; 95 % CI: 5.16-1307.45) and TDF (OR  = 16.90; 95 % CI: 2.28-186.30) groups were significantly higher than that in the ETV double-dose group; the 1-year CVR rate in the LAM-TDF group (OR  = 14.82; 95 % CI: 1.03-220.31) was significantly higher than that in the LAM/LdT-ADV group. The 1-year BR rate of ETV-TDF (OR = 28.68; 95 % CI: 1.70-1505.08) and TDF (OR = 21.79; 95 % CI: 1.43-1070.09) therapies were significantly higher than that of ETV double-dose therapy. TDF-based therapies had the highest possibility to achieve the CVR and BR at 1 year, in which LAM-TDF combined therapy was the most effective regimen. The ratio of cost/effectiveness for 1-year treatment was 8 526, 17 649, 20 651 Yuan in the TDF group, TDF-ETV group, and ETV-ADV group, respectively.

CONCLUSIONS

TDF-based combined therapies such as ETV-TDF and LAM-TDF therapies were the first-line treatment if financial condition is allowed.

Switching Lamivudine with Adefovir Dipivoxil Combination Therapy to Entecavir Monotherapy Provides Better Viral Suppression and Kidney Safety

Introduction: Most chronic hepatitis B (CHB) patients in China are primitively treated with a combination of lamivudine (LAM) and adefovir dipivoxil (ADV). Although antiviral resistance can be avoided with this combination therapy, using it can have harmful side effects related to ADV, specifically kidney and bone injury. This study was designed to compare viral suppression and kidney safety when switching LAM and ADV combination therapy de novo to entecavir (ETV) monotherapy in patients with CHB and compensated hepatic cirrhosis. Materials and methods: In total, 360 CHB and compensated liver cirrhosis patients who received treatment of LAM and ADV combination therapy for more than 1 year were included in this study. One hundred and eighty patients continued combination therapy to serve as a control group and the other 180 patients were switched to ETV monotherapy to serve as the experimental group. The total course of therapy was 3 years. Laboratory studies were done every 3 months to measure liver and kidney function. Studies included glomerular filtration rate (eGFR), HBV-DNA, urine β2-microglobulin (β2-M) and retinol binding protein (RBP). Results: In the experimental group, an HBV-DNA level below 20 IU/ml was found in 77.65%, 85.88%, and 94.77% in years 1, 2, and 3, respectively. In the control group, HBV-DNA levels were below 20 IU/ml in 69.66%, 75.42%, and 85.80% in years 1, 2, and 3, respectively. Low HBV-DNA levels in the experimental group were significantly less common than in the control group on the second and third year; P values were 0.009 and 0.006 for years 2 and 3, respectively. The cumulative genetic mutation rate was 3.49% in the experimental group and 8.88% in the control group (P=0.044). Decreases in eGFR more than 30% from baseline were found in 0%, 0.56%, and 1.74% of patients in the experimental group and 4.49%, 9.14% and 14.79% in patients in the control group in the first, second, and third year, respectively. Serum creatinine more than 50 μmol/L above baseline was found in 0%, 0% and 1.74% of patients in the experimental group and 1.12%, 4.00% and 5.32% of patients in the control group in years 1, 2, and 3, respectively. The urine β2-M and RBP levels were abnormal more often in the experimental group than in the control group. Conclusion: Switching to ETV monotherapy can decrease HBV-DNA levels, reduce the genetic mutation rate, and prevent renal damage caused by LAM and ADV combination therapy in patients with CHB and compensated liver cirrhosis. Patients receiving LAM and ADV combination therapy de novo should be switched to ETV monotherapy immediately.

Lactate serum concentrations during treatment with nucleos(t)ide analogues in hepatitis B with or without cirrhosis

OBJECTIVE

The aim of this study is to evaluate the clinical implications of lactate concentrations in patients with hepatitis B with or without cirrhosis during treatment with nucleos(t)ide analogues.

PATIENTS AND METHODS

One hundred and seven consecutive patients with chronic hepatitis B and median age 57 (24-85) years were prospectively included. Lactate concentrations were measured at baseline and at 12, 24, 36, 48, and 60 months following the baseline measurements. Eight (n=8, 7.5%) patients received lamivudine, 38 (n=38, 35.5%) patients received tenofovir, 34 (n=34, 31.8%) patients received entecavir, and 27 (n=27, 25.2%) patients received combined therapy.

RESULTS

None of the patients developed lactic acidosis during follow-up [median: 58 (6-155) months]. Overall, no trends of the lactic acid evolution were observed over time; however, there was a nonsignificant increasing trend in patients with cirrhosis up to 24 months of treatment. This increasing trend was significant in female patients with cirrhosis (P=0.016). The age of the patients, the presence of cirrhosis, and hepatocellular carcinoma were strongly associated with the survival of all patients. In the group of cirrhotic patients, the only independent prognostic factor that was associated with patients' survival was the Child-Pugh class.

CONCLUSION

None of the patients developed lactic acidosis. There is an indication of an increasing trend of lactic acid levels up to 24 months of therapy in female cirrhotic patients.

Cost-Effectiveness Comparison Between the Response-Guided Therapies and Monotherapies of Nucleos(t)ide Analogues for Chronic Hepatitis B Patients in China

BACKGROUND AND OBJECTIVE

Nucleos(t)ide analogue (NA) monotherapies are typically used as the primary treatment for chronic hepatitis B (CHB) patients, including lamivudine (LAM), telbivudine (TBV), adefovir (ADV), entecavir (ETV) and tenofovir (TDF). For high-resistance NAs (LAM, TBV, ADV), they can generate excellent clinical outcomes by using response-guided therapy; however, their pharmacoeconomic profiles remain unclear in China. We aimed to evaluate the cost effectiveness between response-guided therapies and monotherapies of NAs for Chinese hepatitis B e-antigen (HBeAg)-positive and -negative CHB patients.

METHODS

We constructed a Markov model to simulate CHB progression associated with 12 treatment strategies using effectiveness and cost data from the published literature. We measured the lifetime costs, quality adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). One-way sensitivity (especially to extend the range of the TDF price) and probabilistic sensitivity analyses were used to explore the uncertainties of the model.

RESULTS

For both HBeAg-positive and -negative patients, no treatment strategy generated the lowest lifetime costs (US$31,185-US$31,338) and QALYs (7.54-7.58). ETV and TDF monotherapies were not dominated by other treatments, whereas, the ICER of ETV monotherapy was the lowest (US$6112/QALY-US$8533/QALY). For each high-resistance NA, compared with its monotherapy, the ICERs of its response-guided therapies were below the willingness-to-pay threshold of US$22,833/QALY. Additionally, TDF monotherapy was the preferred treatment when its price dropped to US$1820/year or lower.

CONCLUSION

Among 12 treatment strategies evaluated, ETV monotherapy is the most cost-effective treatment for treatment-naive CHB patients in China. The response-guided therapies of high-resistance NAs are more cost-effective than their monotherapies.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LAY SUMMARY

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

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov ID NCT01639092.

Cost-effectiveness comparison of lamivudine plus adefovir combination treatment and nucleos(t)ide analog monotherapies in Chinese chronic hepatitis B patients

BACKGROUND/AIM

Lamivudine (LAM) plus adefovir (ADV) combination therapy is clinically efficacious for treating chronic hepatitis B (CHB) patients in China, but no pharmacoeconomic evaluations of this strategy are available. The aim of this study was to examine the cost-effectiveness of LAM plus ADV combination treatment compared with five other nucleos(t)ide analog monotherapies (LAM, ADV, telbivudine [TBV], entecavir [ETV], and tenofovir [TDF]).

METHODS

To simulate the lifetime (40-year time span) costs and quality-adjusted life-years (QALYs) for different therapy options, a Markov model that included five initial monotherapies and LAM plus ADV combination as an initial treatment was developed. Two kinds of rescue combination strategies (base-case: LAM + ADV then ETV + ADV; alternative: direct use of ETV + ADV) were considered separately for treating patients refractory to initial therapy. One-way and probabilistic sensitivity analyses were used to explore model uncertainties.

RESULTS

In base-case analysis, ETV had the lowest lifetime cost and served as the reference therapy. Compared to the reference, LAM, ADV, and TBV had higher costs and lower efficacy, and were completely dominated by ETV. LAM plus ADV combination therapy or TDF was more efficacious than ETV, but also more expensive. Although the incremental cost-effectiveness ratios of combination therapy or TDF were both higher than the willingness-to-pay threshold of $20,466/QALY gained for the reference treatment, in an alternative scenario analysis LAM plus ADV combination therapy would be the preferable treatment option.

CONCLUSION

ETV and LAM plus ADV combination therapy are both cost-effective strategies for treating Chinese CHB patients.

Chronic hepatitis B: A wave of new therapies on the horizon

This year marks the 50th anniversary of the discovery of the Australia antigen (Blumberg et al., 1965), which in 1967 was identified to be the hepatitis B virus (HBV) surface antigen. Even though several antiviral medications have been in use for the management of chronic HBV infection for more than 20years, sustained clearance of HBsAg, similar to the sustained viral response (SVR) or cure in chronic hepatitis C, occurs in only a minority of treated patients. Moreover, even after 10years of effective suppression of HBV viremia with current therapy, there is only a 40-70% reduction in deaths from liver cancer. Recent success in developing antivirals for hepatitis C that are effective across all genotypes has renewed interest in a similar cure for chronic HBV infection. In this article, we review a wave of newly identified drug targets, investigational compounds and experimental strategies that are now under clinical evaluation or in preclinical development. The paper forms part of a symposium in Antiviral Research on "An unfinished story: From the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."

A novel baseline hepatitis B virus sequencing-based strategy for predicting adefovir antiviral response

Adefovir dipivoxil (ADV) is used as first-line monotherapy or rescue therapy in chronic hepatitis B (CHB) patients. In this study, we sought to identify nucleotide changes in the reverse transcriptase (RT) of hepatitis B virus (HBV) at baseline and explore their predictive value for ADV antiviral response. Ultra-deep pyrosequencing (UDPS) was utilized to determine HBV genetic variability within the RT region at baseline and during a 48-week ADV therapy. According to the viral load at the end of ADV treatment, all patients were classified into responders (HBV DNA level reduction of ⩾ 3 log 10 IU/mL) and suboptimal responders (HBV DNA level reduction of <3 log 10 IU/mL). Based on UDPS data at baseline, we identified 11 nucleotide substitutions whose combination frequency was significantly associated with the antiviral response among 36 CHB patients in the study group. However, the baseline distribution and frequency of rt181 and rt236 substitutions known to confer ADV resistance was a poor predictor for the antiviral response. Compared with baseline serum HBeAg, HBV-DNA and ALT levels, the baseline HBV sequence-based model showed higher predictive accuracy for ADV response. In an independent cohort of 31 validation patients with CHB, the sequence-based model provided greater predictive potency than the HBeAg/HBV-DNA/ALT and the HBeAg/HBV-DNA/ALT/sequence combinations. Taken together, we confirm the presence of ADV resistance variants in treatment-naïve patients and firstly unravel the predictive value of the baseline mutations in the HBV RT region for ADV antiviral response.

Efficacy of entecavir-tenofovir combination therapy for chronic hepatitis B patients with multidrug-resistant strains

The emergence of multidrug-resistant (MDR) strains of hepatitis B virus (HBV) is a major concern. This study aimed to investigate the efficacy and safety of combination therapy with entecavir (ETV) plus tenofovir disoproxil fumarate (TDF) against MDR HBV. To adjust for differences in baseline characteristics, inverse probability weighting (IPW) using propensity scores for the entire cohort and weighted Cox proportional hazards models were applied. Ninety-three consecutive patients who were treated with ETV-TDF combination therapy for >6 months were included; at baseline, 45 were infected with HBV strains with genotypic resistance to lamivudine (LAM) and ETV (the LAM/ETV-R group), 28 with strains resistant to LAM and adefovir (ADV) (the LAM/ADV-R group), and 20 with strains resistant to LAM, ETV, and ADV (the LAM/ETV/ADV-R group). The median duration of rescue therapy was 13.0 (range, 6.7 to 31.7) months. Seventy-four of 93 patients (79.6%) achieved complete virologic suppression, after a median of 4.5 (95% confidence interval, 3.0 to 6.0) months. The cumulative probability of complete virologic suppression at month 6 was 63.6% (55.7%, 75.0%, and 65.0% in the LAM/ETV-R, LAM/ADV-R, and LAM/ETV/ADV-R groups, respectively). During the treatment period, these probabilities were not significantly different across the resistance profiles before and after IPW (P = 0.072 and P = 0.510, respectively). In multivariate analysis, a lower baseline HBV DNA level, but not resistance profiles, was an independent predictor of complete virologic suppression. Renal dysfunction was not observed during the treatment period. In conclusion, rescue therapy with ETV-TDF combination is efficient and safe in patients infected with MDR HBV strains regardless of the antiviral drug resistance profiles.

Efficacy of entecavir-tenofovir combination therapy for chronic hepatitis B patients with multidrug-resistant strains

The emergence of multidrug-resistant (MDR) strains of hepatitis B virus (HBV) is a major concern. This study aimed to investigate the efficacy and safety of combination therapy with entecavir (ETV) plus tenofovir disoproxil fumarate (TDF) against MDR HBV. To adjust for differences in baseline characteristics, inverse probability weighting (IPW) using propensity scores for the entire cohort and weighted Cox proportional hazards models were applied. Ninety-three consecutive patients who were treated with ETV-TDF combination therapy for >6 months were included; at baseline, 45 were infected with HBV strains with genotypic resistance to lamivudine (LAM) and ETV (the LAM/ETV-R group), 28 with strains resistant to LAM and adefovir (ADV) (the LAM/ADV-R group), and 20 with strains resistant to LAM, ETV, and ADV (the LAM/ETV/ADV-R group). The median duration of rescue therapy was 13.0 (range, 6.7 to 31.7) months. Seventy-four of 93 patients (79.6%) achieved complete virologic suppression, after a median of 4.5 (95% confidence interval, 3.0 to 6.0) months. The cumulative probability of complete virologic suppression at month 6 was 63.6% (55.7%, 75.0%, and 65.0% in the LAM/ETV-R, LAM/ADV-R, and LAM/ETV/ADV-R groups, respectively). During the treatment period, these probabilities were not significantly different across the resistance profiles before and after IPW (P = 0.072 and P = 0.510, respectively). In multivariate analysis, a lower baseline HBV DNA level, but not resistance profiles, was an independent predictor of complete virologic suppression. Renal dysfunction was not observed during the treatment period. In conclusion, rescue therapy with ETV-TDF combination is efficient and safe in patients infected with MDR HBV strains regardless of the antiviral drug resistance profiles.