Telbivudine: a review of its use in compensated chronic hepatitis B

Overview of the development of HBV small molecule inhibitors

Like tuberculosis and Acquired Immune Deficiency Syndrome (AIDS), hepatitis B is a globally recognized major public health threat. Although there are many small-molecule drugs for the treatment of hepatitis B, the approved drugs cannot eradicate the pathogenic culprit covalently closed circular DNA in patients, so the patients need long-term medication to control HBV amplification. Driven by a high unmet medical need, many pharmaceutical companies and research institutions have been engaged in the development of anti-HBV drugs to achieve a functional cure for chronic hepatitis B as soon as possible. This review summarizes the pathogenesis of hepatitis B virus and the research progress in the development of anti-HBV small molecule drugs, and introduces the cccDNA formation and transcription inhibitors and core inhibitors in detail, especially emphasizes the role of chinese herbal medicine in the treatment of chronic hepatitis B. Furthermore, this review proposes three potential strategies for cccDNA eradication in the future. We believe this review will provide meaningful guidance to achieve a functional cure for viral hepatitis B in the future.

Marine sponge-derived/inspired drugs and their applications in drug delivery systems

Oceans harbor a vast biodiversity that is not represented in terrestrial habitats. Marine sponges have been the richest source of marine natural products reported to date, and sponge-derived natural products have served as inspiration for the development of several drugs in clinical use. However, many promising sponge-derived drug candidates have been stalled in clinical trials due to lack of efficacy, off-target toxicity, metabolic instability or poor pharmacokinetics. One possible solution to this high clinical failure rate is to design drug delivery systems that deliver drugs in a controlled and specific manner. This review critically analyzes drugs/drug candidates inspired by sponge natural products and the potential use of drug delivery systems as a new strategy to enhance the success rate for translation into clinical use.

Development of nanoparticle-delivery systems for antiviral agents: A review

The COVID-19 pandemic has resulted in unprecedented increases in sickness, death, economic disruption, and social disturbances globally. However, the virus (SARS-CoV-2) that caused this pandemic is only one of many viruses threatening public health. Consequently, it is important to have effective means of preventing viral transmission and reducing its devastating effects on human and animal health. Although many antivirals are already available, their efficacy is often limited because of factors such as poor solubility, low permeability, poor bioavailability, un-targeted release, adverse side effects, and antiviral resistance. Many of these problems can be overcome using advanced antiviral delivery systems constructed using nanotechnology principles. These delivery systems consist of antivirals loaded into nanoparticles, which may be fabricated from either synthetic or natural materials. Nevertheless, there is increasing emphasis on the development of antiviral delivery systems from natural substances, such as lipids, phospholipids, surfactants, proteins, and polysaccharides, due to health and environmental issues. The composition, morphology, dimensions, and interfacial characteristics of nanoparticles can be manipulated to improve the handling, stability, and potency of antivirals. This article outlines the major classes of antivirals, summarizes the challenges currently limiting their efficacy, and highlights how nanoparticles can be used to overcome these challenges. Recent studies on the application of antiviral nanoparticle-based delivery systems are reviewed and future directions are described.

Virtual screening and repurposing of FDA approved drugs against COVID-19 main protease

Aims

In December 2019, the Coronavirus disease-2019 (COVID-19) virus has emerged in Wuhan, China. In this research, the first resolved COVID-19 crystal structure (main protease) was targeted in a virtual screening study by of FDA approved drugs dataset. In addition, a knowledge gap in relations of COVID-19 with the previously known fatal Coronaviruses (CoVs) epidemics, SARS and MERS CoVs, was covered by investigation of sequence statistics and phylogenetics.

Materials and methods

Molecular modeling, virtual screening, docking, sequence comparison statistics and phylogenetics of the COVID-19 main protease were investigated.

Key findings

COVID-19 Mpro formed a phylogenetic group with SARS CoV that was distant from MERS CoV. The identity% was 96.061 and 51.61 for COVID-19/SARS and COVID-19/MERS CoV sequence comparisons, respectively. The top 20 drugs in the virtual screening studies comprised a broad-spectrum antiviral (ribavirin), anti-hepatitis B virus (telbivudine), two vitamins (vitamin B12 and nicotinamide) and other miscellaneous systemically acting drugs. Of special interest, ribavirin had been used in treating cases of SARS CoV.

Significance

The present study provided a comprehensive targeting of the first resolved COVID+19 structure of Mpro and found a suitable save drugs for repurposing against the viral Mpro. Ribavirin, telbivudine, vitamin B12 and nicotinamide can be combined and used for COVID treatment. This initiative relocates already marketed and approved safe drugs for potential use in COVID-treatment.

In Vitro and In Vivo Renoprotective Effects of Telbivudine in Chronic Hepatitis B Patients Receiving Nucleotide Analogue

AIM

Renal toxicity of adefovir disoproxil (ADV) and tenofovir disoproxil fumarate (TDF) is a significant concern in chronic hepatitis B (CHB) patients. Early observational clinical data suggested that telbivudine (LdT) might have renoprotective effects.

METHODS

In this prospective study, consecutive CHB patients on combined lamivudine (LAM) + ADV/TDF were switched to LdT + ADV/TDF at recruitment and were followed up for 24 months. Estimated glomerular filtration rate (eGFR) was calculated with the modification of diet in renal disease equation. The effects of LdT on cell viability and expression of kidney injury or apoptotic biomarkers were investigated in cultured renal tubular epithelial cell line HK-2.

RESULTS

Thirty-one patients (median age 55 years, 90.3% male) were recruited (54.8% TDF: 45.2% ADV). Serum HBV DNA was undetectable at all time points. Median eGFR was 70.2 (IQR 62.6-77.9) and 81.5 (IQR 63.6-99.1) mL/min/1.73 m² at baseline and 24 months, respectively (p < 0.001). Downstaging of chronic kidney disease was observed in eight (25.8%) patients and was more common in ADV-treated compared to TDF-treated patients (7/8 vs. 1/17, p = 0.011; OR 16, 95% CI 1.643-155.766, p = 0.017). In vitro data showed that adding LdT to ADV or TDF was associated with improved cell viability and lower expression of injury and apoptotic biomarkers compared with ADV or TDF alone. Treatment was prematurely discontinued in four(12.9%) patients due to myalgia.

CONCLUSIONS

Clinical and in vitro data suggest that LdT has renoprotective effects in patients on long-term ADV/TDF treatment. LdT may be considered as an adjuvant therapy in this special group of patients with renal impairment (NCT03778567).

Telbivudine and adefovir dipivoxil combination therapy improves renal function in patients with chronic hepatitis B: A STROBE-compliant article

Few studies have addressed the impact of adefovir dipivoxil (ADV)-based combination therapy on the renal function of patients with chronic hepatitis B (CHB). This study evaluated the effects of ADV combined with other antiviral nucleotide analogs (NAs) on renal function of patients with CHB, and analyzed the risk factors for more than 20% reduction of baseline estimated glomerular filtration rate (eGFR).The data of 164 patients with CHB were retrospectively analyzed in this study. Of the 164 patients, 42 received entecavir (ETV) combined with ADV (ETV + ADV group), 68 lamivudine (LAM) combined with ADV (LAM + ADV group), and 54 telbivudine (LDT) combined with ADV (LDT + ADV group). Serum creatinine (SCr) level, eGFR, and proportion of patients with eGFR ≥ 90 mL/min/1.73 m were observed. Also, the independent risk factors for more than 20% reduction of baseline eGFR were analyzed.After 104-week combination therapy, compared with the baseline level, SCr levels were significantly increased in the ETV + ADV group (67 μmol/L vs 73 μmol/L, P = .012) and LAM + ADV group (68 μmol/L vs 79 μmol/L, P = .008), but it was significantly decreased in the LDT + ADV group (69 μmol/L vs 64 μmol/L, P = .023). Compared with the baseline level, eGFR was significantly decreased in the ETV + ADV group (107.8 mL/min/1.73 m vs 96.1 mL/min 1.73/m, P = .004), and LAM + ADV group (105.4 mL/min/1.73 m vs 87.3 mL/min/1.73 m, P = .000), but it was significantly increased in the LDT + ADV group (104.1 mL/min 1.73/m vs 116.2 mL/min/1.73 m,P = .005). The proportion of patients with normal renal function (≥90 mL/min/1.73 m) was significantly higher in the LDT + ADV group than in the ETV + ADV group (P = .002) and LAM + ADV group (P = .001). Multivariate analysis showed that age (P = .035), male (P = .005), baseline eGFR (P < .001), LAM combined with ADV (P < .008), and ETV combined with ADV (P = .03) were independent risk factors for 20% reduction of baseline eGFR.As compared with ETV and ADV combination therapy as well as LAM and ADV combination therapy, LDT and ADV combination therapy can improve eGFR level, so LDT and ADV combination therapy is suitable for the patients with potential renal impairment.

Telbivudine protects renal function in patients with chronic hepatitis B infection in conjunction with adefovir-based combination therapy

Previous studies have demonstrated that the treatment of chronic hepatitis B (CHB) infection with adefovir (ADV) can impair renal function. In contrast, treatment with telbivudine (LdT) improves renal function in CHB patients. The aim of this study was to evaluate the renoprotective effect of LdT in CHB patients receiving ADV-based combination therapy. The effects of treatment with ADV + LdT on renal function were compared to those resulting from treatment with ADV + entecavir (ETV), ADV + lamivudine (LAM), ADV alone and ETV alone. The consecutive cohort analysis included 831 CHB patients who received ADV + LdT, ADV + LAM, ADV + ETV, ADV alone or ETV alone for 96 weeks. Alterations in estimated glomerular filtration rate (eGFR) were compared between the five groups using a linear mixed-effects model. HBV DNA levels were also compared between the five groups during the 96-week period. Among the five treatment groups, significant improvements in eGFR were observed in the ADV + LdT and ADV + LAM groups over time (P < 0.001 for each group compared with baseline eGFR). In patients with a baseline eGFR between 50 and 90 mL/min, the change in eGFR was the most significant in the ADV + LdT group (+0.641 mL/min; P < 0.001). Age, gender, baseline eGFR and treatment option were significant predictive factors for eGFR changes. In conclusion, our results suggest that the combination therapy of LdT and ADV is significantly associated with renoprotective effects in CHB patients when compared with other ADV-based combination or single therapies.

Efficacy of switching to telbivudine plus adefovir in suboptimal responders to lamivudine plus adefovir

AIM: To examine the efficacy of telbivudine (LdT) + adefovir (ADV) vs continuation of lamivudine (LAM) + ADV in patients with LAM-resistant chronic hepatitis B (CHB) who show a suboptimal response to LAM + ADV.

METHODS: This was a randomized, active-control, open-label, single-center, parallel trial. All eligible patients were enrolled in this study in Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea, between March 2010 and March 2011. Hepatitis Be antigen (HBeAg)-positive CHB patients whose serum hepatitis B virus (HBV) DNA remained detectable despite at least 6 mo of LAM + ADV therapy were included. Enrolled patients were randomized to either switching to LdT (600 mg/d orally) plus ADV (10 mg/d orally) (LdT + ADV group) or to continuation with LAM (100 mg/d orally) plus ADV (10 mg/d orally) (LAM + ADV group), and were followed for 48 wk. One hundred and six patients completed the 48-wk treatment period. Serum HBV DNA, HBeAg status, liver biochemistry and safety were monitored at baseline and week 12, 24, 36 and 48.

RESULTS: The duration of prior LAM + ADV treatment was 18.3 (LdT + ADV) and 14.9 mo (LAM + ADV), respectively (P = 0.131). No difference was seen in baseline serum HBV DNA between the two groups [3.66 (LdT + ADV) vs 3.76 (LAM + ADV) log₁₀ IU/mL, P = 0.729]. At week 48, although there was no significant difference in the mean reduction of serum HBV DNA from baseline between LdT + ADV group and LAM + ADV group (-0.81 vs -0.47 log₁₀ IU/mL, P = 0.167), more patients in the LdT + ADV group had undetectable HBV DNA levels compared to those in the LAM + ADV group (30.2% vs 11.5%, P = 0.019). Three patients with LdT + ADV treatment and 2 patients with LAM + ADV treatment achieved HBeAg loss. The patients in both groups tolerated the treatment well without serious adverse events. The proportion of patients with estimated glomerular filtration rate ≥ 90 mL/min per 1.73 m² in the LdT + ADV group increased from 49.1% (26/53) at baseline to 58.5% (31/53) at week 48, while that in the LAM + ADV group decreased from 37.7% (20/53) at baseline to 30.2% (16/53) at week 48.

CONCLUSION: The switch to LdT + ADV in suboptimal responders to LAM + ADV showed a significantly higher rate of virologic response at week 48. These results suggest that LdT + ADV could be a therapeutic option for patients who are unable to use enofovir disoproxil fumarate for any reason.

Telbivudine plus adefovir therapy for chronic hepatitis B patients with virological breakthrough or genotypic resistance to telbivudine

BACKGROUND/AIM

There is very limited experience in the management of telbivudine (LdT)-associated virological breakthrough (VBT) and resistance in the treatment of chronic hepatitis B (CHB) patients, and the guideline recommendations are primitively based on the general principles of rescue therapy to nucleos(t)ide analog resistance. The aim of this study is to determine the effect of the addition of adefovir (ADV) in hepatitis B e antigen (HBeAg)-positive CHB patients with VBT or resistance to LdT.

METHODS

Thirty-seven CHB patients with confirmed VBT and 31 patients with genotypic resistance to LdT were enrolled and thereafter treated with a combination of LdT and ADV for 12 months.

RESULTS

Combination therapy was safe and the majority of patients tolerated the therapy. LdT+ADV led to rapid decreases in viral loads, and viral replications were persistently suppressed, with 2.17 (VBT) and 2.31 (resistance) log(10) copies/ml reductions 12 months after rescue therapy, respectively. The rates corresponding to virological and biochemical responses were similar between the two groups at the end of observations (70.3 vs. 74.2% for virological response, P=0.720; 64.0 vs. 65.5% for biochemical response, P=0.907). The cumulative rates of serological responses were higher in patients with VBT than in those with resistance (35.1 vs. 9.67% for HBeAg loss, P=0.014; 10.8 vs. 3.23% for HBeAg/anti-HBe seroconversion, P=0.233).

CONCLUSION

LdT and ADV combination therapy led to significant decreases in serum hepatitis B virus DNA levels and normalization of alanine aminotransferase levels in patients with VBT or genotypic resistance to LdT. This rescue strategy was also associated with a higher rate of HBeAg serological outcomes in patients with confirmed LdT-related VBT.

Efficacy and safety of telbivudine plus adefovir dipivoxil combination therapy and entecavir monotherapy for HBeAg-positive chronic hepatitis B patients with resistance to adefovir dipivoxil

The objective of this study was to compare the efficacy and safety of two rescue strategies for hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients with resistance to adefovir dipivoxil (ADV). This prospective study included 58 HBeAg-positive CHB patients with resistance to ADV; 30 patients underwent telbivudine (LdT) plus ADV combination therapy and 28 patients switched to entecavir (ETV) monotherapy. After 48 weeks of treatment, the rates of hepatitis B virus (HBV) DNA <3 log10 copies/mL in the LdT plus ADV group and the ETV group were not significantly different (73.3% vs 57.1%, P = 0.195). Six patients receiving LdT plus ADV had HBeAg seroconversion, while none of the patients receiving ETV alone had HBeAg seroconversion (20% vs 0%, P = 0.039). During the 48-week treatment period, two patients in the ETV monotherapy group had viral breakthrough and the strains were confirmed to be of a variant associated with ETV resistance (rtM204V+ rtL180M+ rtT184G), while one patient receiving LdT plus ADV had viral breakthrough and an LdT-associated resistance mutation (rtM204I) was detected. For the majority of the patients, both LdT plus ADV combination treatment or ETV monotherapy were generally well tolerated, and no serious side effects were observed. Both LdT plus ADV combination therapy and ETV monotherapy led to significant decreases in serum HBV DNA in HBeAg-positive CHB patients with resistance to ADV, and LdT plus ADV combination therapy exhibited a significantly higher rate of HBeAg seroconversion compared with ETV monotherapy.

Two cases of telbivudine-induced myopathy in siblings with chronic hepatitis B

Telbivudine is an L-nucleoside analogue with potent antiviral activity against hepatitis B virus (HBV). Clinical trials have shown that telbivudine has a more potent and sustained antiviral activity with a lower frequency of viral resistance than lamivudine. Although there are several reports concerning the safety profile of telbivudine, most adverse events are described as mild and transient in nature. Here we report two cases of telbivudine-induced myopathy in patients with chronic hepatitis B who were siblings.

Lamivudine plus adefovir or telbivudine plus adefovir for chronic hepatitis B patients with suboptimal response to adefovir

BACKGROUND

There is no standard management of chronic hepatitis B (CHB) patients with suboptimal response to nucleoside/nucleotide analogues (NAs). This study aimed to evaluate two different NA combination therapies in patients with suboptimal response to adefovir (ADV).

METHODS

In this study, 72 CHB patients with suboptimal response to ADV were assessed, with 37 patients receiving lamivudine plus ADV (group A) and 35 patients receiving telbivudine plus ADV (group B).

RESULTS

Baseline characteristics between two groups were similar. At month 12, rates of biochemical response (BR) and virological response (VR) were similar between groups A and B (17/19 versus 18/20 for BR, [P=0.269] and 30/37 versus 31/35 for VR [P=0.377]), and cumulative rates of serological response were greater in group B than in group A (10/26 versus 2/28 in hepatitis B e antigen [HBeAg] loss [P=0.006] and 7/26 versus 1/28 in HBeAg/hepatitis B e antibody seroconversion [P=0.022]). After 12-month treatment, 8.1% (3/37) of patients in group A and 5.7% (2/35) of patients in group B had VR; among patients in group A, two had rtM204V/I and rtL180M and one had rtN236T, whereas the two patients in group B had rtM204I+rtL180M.

CONCLUSIONS

Both combination therapies led to a significant decrease in HBV DNA. HBeAg serological outcomes were higher with telbivudine plus ADV combination therapy.

Effect and Predictive Elements for 52 Weeks' Telbivudine Treatment on Naïve HBeAg positive Chronic Hepatitis B

BACKGROUND

Antiviral treatment with nucleoside analogs has been used for chronic hepatitis B (CHB). Each kind of nucleoside analog has its own characteristics and suitability for patients. Telbivudine (LdT, brand name: Sebivo, Beijing Novartis Pharma Ltd) is the newest nucleoside analog, with strong and rapid viral suppression. However, its resistance rate is relatively high during long-term application, due to low genetic barriers to resistance. So, it is necessary to increase the effect and reduce resistance with effective management, according to baseline factors and early on-treatment responses.

OBJECTIVES

To reveal possible predictive factors of the effect of telbivudine (LdT) treatment on naïve HBeAg-positive chronic hepatitis B (CHB) patients to optimize treatment.

PATIENTS AND METHODS

A total 71 naïve chronic hepatitis B (CHB) patients who met the inclusion criteria were enrolled. All patients were treated with LdT 600 mg Qd for at least 52 weeks. Multiple logistic regression analyses were done to investigate the predictive values of baseline factors and responses at Week 24.

RESULTS

The reduction in hepatitis virus B (HBV) DNA level was 6.44 ± 2.38 lg copies/mL at Week 52 compared with baseline. The complete virus response (CVR), biochemical response (BR), serological response (SR), and drug resistance (DR) were 61.99%, 77.46%, 35.21%, and 8.45% respectively. By multiple regression analysis, baseline alanine aminotransferase (ALT) levels significantly affected CVR (P = 0.024, OR = 1.008), and baseline ALT and baseline HBV DNA levels were independent compact factors of SR (P = 0.012, OR = 1.007; P = 0.001, OR = 0.423). The differences in CVR, SR, and DR in patients with ALT > 120 Iu/mL compared with patients with ALT ≤ 120 Iu/mL were statistically significant. The differences in SR in patients with HBV DNA > 107 copies/mL compared with patients with HBV DNA ≤ 107 copies/mL were statistically significant. Additionally, CVR, BR, and SR were differed significantly between patients with HBV DNA lower than 300 copies/mL at Week 24 and patients with HBV DNA higher than 300 copies/mL (P = 0.000, P = 0.0016, and P = 0.000, respectively).

CONCLUSIONS

There were more responders among naïve HBeAg-positive chronic hepatitis B patients with lower HBV DNA levels (especially lower than 107 copies/mL) and higher ALT values (especially higher than 120 Iu/mL at baseline) to LdT treatment. Adjustments for treatment strategy should be considered if HBV DNA > 300 copies/mL at Week 24 is observed.