Entecavir plus tenofovir combination therapy in patients with multidrug-resistant chronic hepatitis B: results of a multicentre, prospective study

Tenofovir-induced osteopenia and hyperparathyroidism: A case report and literature review

Tenofovir disoproxil fumarate is the first-line antiviral therapy for chronic viral hepatitis B, but long-term use is associated with renal failure and hypophosphatemic osteomalacia. Tenofovir disoproxil fumarate-induced osteoporosis and secondary hyperparathyroidism are less commonly reported. Herein, we describe the case of a patient with bone and multijoint pain who was initially misdiagnosed as having normocalcemic primary hyperparathyroidism associated with prolonged exposure to tenofovir disoproxil fumarate. The patient's 24-h urinary calcium and phosphorus excretion levels and serum calcium levels were at the lower end of the normal range. After reviewing these findings, the diagnosis was amended to osteoporosis and secondary hyperparathyroidism caused by tenofovir disoproxil fumarate. In this report, we describe the differences in clinical and laboratory manifestations of hyperparathyroidism induced by tenofovir disoproxil fumarate and normocalcemic primary hyperparathyroidism. We also discuss relevant pathophysiological mechanisms and propose a feasible treatment strategy.

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

Background/Aims

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

Methods

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

Results

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

Conclusions

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

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

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

HBV replication inhibitors

Chronic Hepatitis B Virus infections afflict >250 million people and kill nearly 1 million annually. Current non-curative therapies are dominated by nucleos(t)ide analogs (NAs) that profoundly but incompletely suppress DNA synthesis by the viral reverse transcriptase. Residual HBV replication during NA therapy contributes to maintenance of the critical nuclear reservoir of the HBV genome, the covalently-closed circular DNA, and to ongoing infection of naive cells. Identification of next-generation NAs with improved efficacy and safety profiles, often through novel prodrug approaches, is the primary thrust of ongoing efforts to improve HBV replication inhibitors. Inhibitors of the HBV ribonuclease H, the other viral enzymatic activity essential for viral genomic replication, are in preclinical development. The complexity of HBV's reverse transcription pathway offers many other potential targets. HBV's protein-priming of reverse transcription has been briefly explored as a potential target, as have the host chaperones necessary for function of the HBV reverse transcriptase. Improved inhibitors of HBV reverse transcription would reduce HBV's replication-dependent persistence mechanisms and are therefore expected to become a backbone of future curative combination anti-HBV therapies.

An observational study on long-term renal outcome in patients with chronic hepatitis B treated with tenofovir disoproxil fumarate

In patients with chronic hepatitis B (CHB), long-term effects of tenofovir disoproxil fumarate (TDF) on renal function have been controversial. This study aimed to analyse the real-world long-term effects of TDF on renal function in Korean patients with CHB. We analysed a cohort of 640 treatment-naïve patients with CHB who were treated with TDF between May 2012 and December 2015 at Severance Hospital, Seoul, Republic of Korea. The mean age was 48.3 years old, and 59.5% were male. The proportions of hypertension and diabetes mellitus (DM) were 11.6% and 14.2%, respectively, and that of liver cirrhosis was 20.8%. During the 5-year follow-up, using a linear mixed model, serum creatinine increased from 0.77 ± 0.01 mg/dL to 0.85 ± 0.02 mg/dL (P < .001), and eGFR decreased from 102.6 ± 0.6 mL/min/1.73 m² to 93.4 ± 1.4 mL/min/1.73 m² (P < .001). In subgroup analysis, eGFR was statistically more decreased in patients with age > 60 than ≦60 years old (P = .027), and in patients with diuretic use than without diuretic use (P = .008). In multivariate analysis, the independent risk factors for eGFR decrease > 20% were baseline eGFR < 60mL/min/1.73 m² (P = .034) and the use of diuretics (P < .001). CHB patients on TDF experienced greater reduction in renal function with age > 60 and with diuretic use compared to those without these characteristics. Baseline eGFR < 60 mL/min/1.73 m² and use of diuretics were independent risk factors of eGFR decline of more than 20% on TDF therapy.

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.

Step-down strategy in antiviral resistant chronic hepatitis B patients who achieved viral suppression with rescue combination therapy

In the treatment of chronic hepatitis B (CHB) patients with drug resistance, rescue combination therapy leads to viral suppression in almost all patients. However, once it is achieved, lifelong maintenance especially, by using combination therapy is not always possible in a significant proportion of patients. At present, there is no consensus on whether it is possible to switch to monotherapy from combination therapy. However, there is robust evidence to support step-down therapy, which involves switching from combination therapy to monotherapy in antiviral resistant CHB patients who achieve complete viral response from combination therapy. We review the evidence in favor of switching to monotherapy in antiviral resistant CHB patients who achieve complete viral response by combination therapy.

Switching from tenofovir and nucleoside analogue therapy to tenofovir monotherapy in virologically suppressed chronic hepatitis B patients with antiviral resistance

It is unclear whether chronic hepatitis B (CHB) patients with antiviral resistance, who achieve a complete virologic response (CVR) with tenofovir disoproxil fumarate (TDF) and nucleoside analogue (NUC) combination therapy, maintain CVR if switched to TDF monotherapy. We investigated the persistence of CVR after cessation of NUC in virologically suppressed antiviral resistant CHB patients using TDF+NUC combination therapy. This study recruited 76 antiviral-resistant CHB patients showing CVR on TDF+entecavir (ETV) (n = 52), TDF+lamivudine (LAM; n = 14), and TDF+telbivudine (LdT; n = 10) combination therapy, who were switched to TDF monotherapy as step-down therapy. At baseline, 47 patients were male and the median age was 53.0 years (range: 30-78 years); 72.3% cases were hepatitis B e antigen-positive (HBeAg+) and 23.7% were of liver cirrhosis. The median duration of TDF+NUC combination therapy was 20.8 months (range: 3-46 months). At a median follow-up of 24.7 months (range: 12-48 months) after switching to TDF monotherapy, all 76 patients maintained CVR, regardless of the duration of combination therapy and the type of prior NUC and antiviral resistance. Renal dysfunction was not observed during the treatment period. The step-down strategy of switching from TDF+NUC combination therapy to TDF monotherapy in virologically suppressed CHB patients with antiviral resistance should be considered.

Renal safety of tenofovir and/or entecavir in patients with chronic HBV monoinfection

Background

Tenofovir disoproxil fumarate (TDF) and entecavir (ETV) are recommended as the first-line therapy for chronic hepatitis B (CHB) due to their genetic barrier to resistance and effectiveness of virological suppression. TDF and ETV may cause renal toxicity through various mechanisms such as renal tubular injury, apoptosis, and mitochondrial toxicity. The aims of the current review were to assess the potential renal toxicity associated with the use of TDF and ETV in patients infected with chronic hepatitis B virus (HBV) and to provide clinical perspectives on these two agents in the treatment of CHB.

Methods

A literature search of clinical studies published in PubMed and posted on ClinicalTrials.gov website was implemented to find studies evaluating the potential renal toxicity of TDF and ETV.

Results

Twenty-one studies were examined in this review. The TDF dose used in the studies was 245 or 300 mg/day and that of ETV was 0.5 or 1 mg/day. Based on the markers of renal function, patients treated with TDF were not more likely to show changes in renal function than those treated with ETV; however, the estimated glomerular filtration rates (eGFRs) of patients receiving TDF tended to be more clearly reduced than those of patients receiving ETV. The eGFRs of patients treated with TDF decreased in a time-dependent manner, whereas those of patients treated with ETV increased or decreased across various time points.

Conclusion

The data shown in this study suggest that use of TDF and ETV could be at least associated with reductions in renal function in patients with chronic HBV infection. However, various risk factors, such as pre-existing renal failure and comorbidities, are also associated with decreased renal function during the treatment of TDF and ETV. Thus, studies of management strategies for HBV-infected patients with these risk factors are necessary in the near future.

Comparison of the Efficacy of Tenofovir Versus Tenofovir plus Entecavir in the Treatment of Chronic Hepatitis B in Patients With Poor Efficacy of Entecavir: A Systematic Review and Meta-analysis

PURPOSE

This study aimed to compare the efficacy between tenofovir disoproxil fumarate (TDF) and TDF plus entecavir (ETV) combination therapy in patients with chronic hepatitis B (CHB) with a poor response to ETV.

METHODS

We searched the China National Knowledge Infrastructure (CNKI), PubMed, EMBASE, and SCOPE libraries for articles using the keywords chronic hepatitis B virus or CHB or HBV, entecavir or ETV, and tenofovir or TDF.

FINDINGS

Five studies (from CNKI and PubMed) with a total of 408 patients met the inclusion criteria: 212 patients in the TDF group and 196 patients in the TDF plus ETV group. The rates of viral suppression between the 2 groups were comparable at weeks 24 and 48 of treatment (P = 0.546 vs P = 0.818). In addition, the subanalysis revealed that no significant differences were observed in the rates of viral suppression between the 2 groups at week 24 (subgroup 1 [partial response to ETV]: P = 0.822; subgroup 2 [resistance to ETV]: P = 0.294) and week 48 (subgroup 1: P = 0.797; subgroup 2: P = 0.545). No significant differences were found in alanine aminotransferase normalization, hepatitis B e antigen loss, hepatitis B e antigen seroconversion, virologic breakthrough, and tolerability between the 2 groups at weeks 24 and 48. Therefore, the results suggest that TDF monotherapy should be chosen for patients with CHB with a poor response to ETV for reasons of economy and convenience.

IMPLICATIONS

We conclude that TDF monotherapy is comparable to TDF-ETV combination therapy for patients with a poor response to ETV; thus, TDF monotherapy may be a better choice for these patients. However, because of the limited citations in this meta-analysis, complete and systematic evidence is needed to evaluate the differences in efficacy and tolerability between TDF and TDF-ETV. Larger and longer randomized clinical trials and further studies should be conducted to verify the results.

EASL 2017 Clinical Practice Guidelines on the management of hepatitis B virus infection

Hepatitis B virus (HBV) infection remains a global public health problem with changing epidemiology due to several factors including vaccination policies and migration. This Clinical Practice Guideline presents updated recommendations for the optimal management of HBV infection. Chronic HBV infection can be classified into five phases: (I) HBeAg-positive chronic infection, (II) HBeAg-positive chronic hepatitis, (III) HBeAg-negative chronic infection, (IV) HBeAg-negative chronic hepatitis and (V) HBsAg-negative phase. All patients with chronic HBV infection are at increased risk of progression to cirrhosis and hepatocellular carcinoma (HCC), depending on host and viral factors. The main goal of therapy is to improve survival and quality of life by preventing disease progression, and consequently HCC development. The induction of long-term suppression of HBV replication represents the main endpoint of current treatment strategies, while HBsAg loss is an optimal endpoint. The typical indication for treatment requires HBV DNA >2,000IU/ml, elevated ALT and/or at least moderate histological lesions, while all cirrhotic patients with detectable HBV DNA should be treated. Additional indications include the prevention of mother to child transmission in pregnant women with high viremia and prevention of HBV reactivation in patients requiring immunosuppression or chemotherapy. The long-term administration of a potent nucleos(t)ide analogue with high barrier to resistance, i.e., entecavir, tenofovir disoproxil or tenofovir alafenamide, represents the treatment of choice. Pegylated interferon-alfa treatment can also be considered in mild to moderate chronic hepatitis B patients. Combination therapies are not generally recommended. All patients should be monitored for risk of disease progression and HCC. Treated patients should be monitored for therapy response and adherence. HCC remains the major concern for treated chronic hepatitis B patients. Several subgroups of patients with HBV infection require specific focus. Future treatment strategies to achieve 'cure' of disease and new biomarkers are discussed.

Efficacy of long-term tenofovir-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs

BACKGROUND

Few studies have investigated the efficacy of long-term tenofovir disoproxil fumarate (TDF)-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs.

METHODS

We retrospectively analyzed 40 Japanese patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs who received TDF-based rescue therapy [TDF monotherapy, TDF plus lamivudine (LAM) combination therapy, or TDF plus entecavir (ETV) combination therapy] followed up for a median of 45 months (range 14-99 months). Viral response, changes in hepatitis B surface antigen levels from the baseline, and viral breakthrough during therapy were analyzed.

RESULTS

The proportion of patients with undetectable serum hepatitis B virus (HBV) DNA levels (less than 2.1 log copies per milliliter) (viral response) during TDF-based rescue therapy was 68, 78, 85, 88, 83, 81, 88, and 100 % at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4 years respectively. There were no differences in the viral response rate between the TDF plus LAM group and the TDF plus ETV group. The mean reduction from the baseline in hepatitis B surface antigen levels in patients with LAM-resistant HBV was greater than the reductions in patients with adefovir dipivoxil (ADV)-resistant or ETV-resistant HBV at 2 and 3 years (P = 0.024, and P = 0.025 respectively). However, two patients with ADV- or ETV-resistant HBV at the baseline developed viral breakthrough during TDF-based rescue therapy.

CONCLUSIONS

Long-term therapy with a TDF-based rescue regimen demonstrated high viral suppression in patients in whom LAM plus ADV combination therapy, ETV plus ADV combination therapy, or ETV monotherapy had failed. However, patients with ADV- or ETV-resistant HBV at the baseline may develop viral breakthrough and resistance, and careful follow-up is advised.

Tenofovir versus tenofovir plus entecavir for chronic hepatitis B with lamivudine resistance and entecavir resistance

We compared the viral suppressive efficacy of tenofovir disoproxil fumarate (TDF) mono-rescue therapy (TDF group) and TDF plus entecavir (ETV) combination-rescue therapy (TDF + ETV group) in chronic hepatitis B (CHB) patients with lamivudine resistance and entecavir resistance. One hundred and thirty-three CHB patients with lamivudine and entecavir resistance were investigated. Ninety-six patients were treated with TDF and 37 with TDF + ETV for at least 6 months. We compared the virologic response rate (HBV DNA level <20 IU/mL) between the two groups and identified the predictive factors of treatment outcome. There were no significant differences between the two groups in demographic characteristics. Up to 24 months [median: 18 (range 6-24) months], 85.4% and 89.2% of the TDF group and TDF + ETV group, respectively, achieved a virologic response (P=.068). Only the HBV DNA level at baseline was significantly associated with a virologic response in the multivariate analysis. In a subanalysis of patients with HBV DNA levels ≥4 log (IU/mL) at baseline, a higher proportion of patients in the TDF + ETV group than the TDF group achieved a virologic response (92.9% vs 68.3%; P<.001), while 90% of patients with HBV DNA (IU/mL) levels <4 log in all both TDF and TDF + ETV groups achieved a virologic response. TDF mono-rescue therapy is a reasonable option in patients with lamivudine resistance and entecavir resistance. However, the combination strategy should be considered in patients with high baseline HBV DNA levels.

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.

Recent advances in treatment of chronic hepatitis B with entecavir

Entecavir (ETV) is a potent hepatitis B virus inhibitor with a high barrier to resistance, and it has been recommended as one of the first-line drugs for treating chronic hepatitis B (CHB) by guidelines from several international and national societies. This paper reviews the recent advances in the treatment of CHB with ETV, in terms of treatment adherence, efficacy in the treatment of various kinds of patients with CHB, management of patients with partial virological response, viral resistance or treatment failure to ETV, treatment cessation, sequential or combination therapy with ETV and pegylated interferon, as well as the surveillance of hepatocellular carcinoma.

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.

Durability of the virological response after lamivudine discontinuation in lamivudine-resistant patients with a complete virological response after lamivudine and adefovir combination therapy

We investigated the durability of virological response after lamivudine (LAM) discontinuation in LAM-resistant chronic hepatitis B (CHB) patients with complete virological response after LAM-adefovir (ADV) combination therapy. We enrolled 58 patients switched to ADV monotherapy with undetectable viral loads (<12 IU/ml) and normal alanine aminotransferase levels after ADV add-on combination treatment for at least 6 months in LAM-resistant CHB patients. Virologic relapse was defined as HBV DNA detection at more than 20 IU/ml by quantitative polymerase chain reaction determined on two consecutive measurements. During median 40.9 months of follow-up (range 11.5-79.0 months), seven (12.1%) patients experienced virological relapse. The cumulative rate of virological relapse at 3 and 5 years was 5.5% and 22.4%, respectively. Two patients had elevated alanine aminotransferase during virological relapse. These seven patients with virological relapse had undetectable HBV DNA after switching to tenofovir therapy. In our study, switching to ADV monotherapy resulted in sustained HBV DNA suppression in 87.9% of the patients during median 40.9 months follow-up. This adapting step-down strategy, switching from combination therapy to monotherapy in virologically suppressed CHB patients with stable liver disease, may reduce the cost burden and the risk of potentially harmful effects of combination therapy. J. Med. Virol. 89:85-90, 2017. © 2016 Wiley Periodicals, Inc.