Adefovir dipivoxil for the treatment of hepatitis B e antigen-negative chronic hepatitis B

LP340, a novel histone deacetylase inhibitor, decreases liver injury and fibrosis in mice: role of oxidative stress and microRNA-23a

Effective therapy for liver fibrosis is lacking. Here, we examined whether LP340, the lead candidate of a new-generation of hydrazide-based HDAC1,2,3 inhibitors (HDACi), decreases liver fibrosis. Liver fibrosis was induced by CCl4 treatment and bile duct ligation (BDL) in mice. At 6 weeks after CCl4, serum alanine aminotransferase increased, and necrotic cell death and leukocyte infiltration occurred in the liver. Tumor necrosis factor-α and myeloperoxidase markedly increased, indicating inflammation. After 6 weeks, α-smooth muscle actin (αSMA) and collagen-1 expression increased by 80% and 575%, respectively, indicating hepatic stellate cell (HSC) activation and fibrogenesis. Fibrosis detected by trichrome and Sirius-red staining occurred primarily in pericentral regions with some bridging fibrosis in liver sections. 4-Hydroxynonenal adducts (indicator of oxidative stress), profibrotic cytokine transforming growth factor-β (TGFβ), and TGFβ downstream signaling molecules phospho-Smad2/3 also markedly increased. LP340 attenuated indices of liver injury, inflammation, and fibrosis markedly. Moreover, Ski-related novel protein-N (SnoN), an endogenous inhibitor of TGFβ signaling, decreased, whereas SnoN expression suppressor microRNA-23a (miR23a) increased markedly. LP340 (0.05 mg/kg, ig., daily during the last 2 weeks of CCl4 treatment) decreased 4-hydroxynonenal adducts and miR23a production, blunted SnoN decreases, and inhibited the TGFβ/Smad signaling. By contrast, LP340 had no effect on matrix metalloproteinase-9 expression. LP340 increased histone-3 acetylation but not tubulin acetylation, indicating that LP340 inhibited Class-I but not Class-II HDAC in vivo. After BDL, focal necrosis, inflammation, ductular reactions, and portal and bridging fibrosis occurred at 2 weeks, and αSMA and collagen-1 expression increased by 256% and 560%, respectively. LP340 attenuated liver injury, ductular reactions, inflammation, and liver fibrosis. LP340 also decreased 4-hydroxynonenal adducts and miR23a production, prevented SnoN decreases, and inhibited the TGFβ/Smad signaling after BDL. In vitro, LP340 inhibited immortal human hepatic stellate cells (hTERT-HSC) activation in culture (αSMA and collagen-1 expression) as well as miR23a production, demonstrating its direct inhibitory effects on HSC. In conclusions, LP340 is a promising therapy for both portal and pericentral liver fibrosis, and it works by inhibiting oxidative stress and decreasing miR23a.

Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target

Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.

Treatment endpoints for chronic hepatitis D

Management of chronic hepatitis D (CHD) has entered a new era. In this new era, the virus entry inhibitor bulevirtide has received conditional approval as a treatment for compensated CHD. Three phase 3 studies with two new compounds are ongoing for the treatment of CHD. In this context, surrogate markers of treatment efficacy have been well defined for chronic hepatitis B (CHB) (7) and chronic hepatitis C (8) but not for CHD. The aim of this review is to give a perspective on treatment endpoints in CHD. For this, we took guidance from CHB studies and tried to make suggestions which differed according to finite versus prolonged treatment durations and also took into account the different characteristics of the new compounds.

Blockade of CCR4 breaks immune tolerance in chronic hepatitis B patients by modulating regulatory pathways

BACKGROUND

Immunotargets including checkpoint inhibitors and toll-like receptor 8 agonists have recently gained attention for the recovery of hepatitis B virus (HBV)-specific T cell exhaustion in chronic hepatitis B(CHB). Chemokine receptors have a similar significant role during viral infections; however, their role in CHB remains poorly understood. Therefore, in this study we evaluated the role of chemokine receptor 4 (CCR4) in deriving immunosuppression during CHB.

METHODS

We characterized CCR4+CD8+ T cells in CHB and identified their involvement in immunosuppression. Further, we examined if CCR4 blockade with mogamulizumab antibody can recover the functional exhaustion in HBsAg-specific T cells.

RESULTS

CHB patients exhibit higher frequency of CCR4+CD8+ T cells that increase with higher HBsAg levels and fibrosis scores. In vitro, HBs antigen triggers CCR4 expression. These cells express multiple inhibitory receptors and exhibit immunosuppressive functions by producing excessive immunoregulatory cytokines IL-4, IL-5, IL-10 and TGF-β1. CCR4 Blockade significantly boosted HBsAg-specific antiviral-cytokine production(IFN-γ, TNF-α and IL-21) in T cells through enhancing their proliferation capacity and polarizing these cells towards T helper 1(Th1) and T follicular helper cells(T_FH) in case of CD4 cells, and cytotoxic T cell 1(TC1) and cytotoxic T follicular(T_CF) cells in case of CD8. Cytotoxic potential was improved, while no induction of immunosuppressive-cytokines was seen after anti-CCR4 treatment thereby eliminating the risk of treatment-induced immunosuppression. CCR4 blockade inhibited the development and effector function of Tregs by controlling their expansion and TGF-β1 production preventing Tregs-induced immunotolearance.

CONCLUSIONS

CCR4 blockade reconstitutes antiviral immune response in T cells and limits the immunosuppressive functions of Tregs, representing them as a promising immunotherapeutic target for functional cure of CHB.

Global dynamics of multiple delays within-host model for a hepatitis B virus infection of hepatocytes with immune response and drug therapy

In this paper, a mathematical model describing the hepatitis B virus (HBV) infection of hepatocytes with the intracellular HBV-DNA containing capsids, cytotoxic T-lymphocyte (CTL), antibodies including drug therapy (blocking new infection and inhibiting viral production) with two-time delays is studied. It incorporates the delay in the productively infected hepatocytes and the delay in an antigenic stimulation generating CTL. We verify the positivity and boundedness of solutions and determine the basic reproduction number. The local and global stability of three equilibrium points (infection-free, immune-free, and immune-activated) are investigated. Finally, the numerical simulations are established to show the role of these therapies in reducing viral replication and HBV infection. Our results show that the treatment by blocking new infection gives more significant results than the treatment by inhibiting viral production for infected hepatocytes. Further, both delays affect the number of infections and duration i.e. the longer the delay, the more severe the HBV infection.

Health inequalities in the management of chronic hepatitis B virus infection in patients from sub-Saharan Africa in high-income countries

Chronic hepatitis B virus disproportionately affects migrant communities in high-income countries, reflecting increased migration from sub-Saharan Africa. Chronic hepatitis B virus is endemic in sub-Saharan Africa, yet the natural history of chronic infection experienced by patients remains incompletely understood, with evidence of variability across genotypes and regions within sub-Saharan Africa. Clinical guidelines recommending treatment thresholds are not specific to sub-Saharan African patients and are based on natural history studies from Western Pacific Asian countries. Access to standard of care treatment is available for sub-Saharan African people with chronic hepatitis B virus infection in high-income countries; however, the evidence base for these treatments was not established in this cohort and areas of uncertainty remain, particularly regarding HCC surveillance and treatment discontinuation. Participation in phase III clinical trials for chronic hepatitis B therapies is almost non-existent amongst sub-Saharan African patients, even when residing in high-income countries that participate in multicentre trials. Engagement with sub-Saharan African patients with chronic hepatitis B in high-income countries is challenging because of the stigma associated with the diagnosis, absence of routine screening systems and the complexities involved in navigating the healthcare system. Nonetheless, improved engagement is critical if we are to achieve global hepatitis B virus elimination.

The RNA-Binding Protein ELAVL1 Regulates Hepatitis B Virus Replication and Growth of Hepatocellular Carcinoma Cells

Previous RNA immunoprecipitation followed by proteomic approaches successfully demonstrated that Embryonic Lethal, Abnormal Vision, Drosophila-Like 1 (ELAVL1) interacts with hepatitis B virus (HBV)-derived RNAs. Although ELAVL family proteins stabilize AU-rich element (ARE)-containing mRNAs, their role in HBV transcription remains unclear. This study conducted loss-of-function assays of ELAVL1 for inducible HBV-replicating HepAD38 cells and HBx-overexpressed HepG2 cells. In addition, clinicopathological analyses in primary hepatocellular carcinoma (HCC) surgical samples were also conducted. Lentivirus-mediated short hairpin RNA knockdown of ELAVL1 resulted in a decrease in both viral RNA transcription and production of viral proteins, including HBs and HBx, probably due to RNA stabilization by ELAVL1. Cell growth of HepAD38 cells was more significantly impaired in ELAVL1-knockdown than those in the control group, with or without HBV replication, indicating that ELAVL1 is involved in proliferation by factors other than HBV-derived RNAs. Immunohistochemical analyses of 77 paired HCC surgical specimens demonstrated that diffuse ELAVL1 expression was detected more frequently in HCC tissues (61.0%) than in non-tumor tissues (27.3%). In addition, the abundant expression of ELAVL1 tended to affect postoperative recurrence in HBV-related HCC patients. In conclusion, ELAVL1 contributes not only to HBV replication but also to HCC cell growth. It may be a potent therapeutic target for HBV-related HCC treatment.

Pradefovir Treatment in Patients With Chronic Hepatitis B: Week 24 Results From a Multicenter, Double-Blind, Randomized, Noninferiority, Phase 2 Trial

BACKGROUND

Pradefovir is a liver-targeted prodrug of adefovir, a nucleoside/nucleotide analogue with antiviral activity against hepatitis B virus (HBV) DNA polymerase. This phase 2 study compared the efficacy and safety of oral pradefovir (30, 45, 60, or 75 mg) versus tenofovir disoproxil fumarate (TDF; 300 mg) and aimed to identify the most appropriate dose of pradefovir for the forthcoming phase 3 study.

METHODS

Treatment-naive and experienced (not on treatment >6 months) patients with chronic hepatitis B were eligible.

RESULTS

A total of 240 participants were randomized and treated in the study (48 per group). Approximately 80% were hepatitis B e antigen (HBeAg) positive, and 10% had liver cirrhosis. The reductions from baseline in HBV DNA levels achieved at week 24 were 5.40, 5.34, 5.33, and 5.40 log10 IU/mL, with pradefovir doses of 30-, 45-, 60-, and 75-mg, respectively, compared with 5.12 log10 IU/mL with TDF. However, HBeAg loss was attained by more participants who received 45-, 60-, or 75-mg pradefovir than by those receiving TDF (12%, 6%, and 9% vs 3%). The TDF group exhibited a more significant increase in serum creatinine than the pradefovir 30- and 45-mg groups, and serum phosphate levels were comparable among all groups. Most adverse events (AEs) were mild (grade 1). No treatment-related severe AEs were reported. Overall, AEs and laboratory abnormalities were comparable to those in the TDF group.

CONCLUSIONS

Pradefovir and TDF exhibited comparable reductions in HBV DNA levels. All treatments were safe and well tolerated.

CLINICAL TRIALS REGISTRATION

NCT00230503 and China Drug Trials CTR2018042.

Adefovir for lamivudine-resistant hepatitis B

Adefovir, a nucleotide analog developed by John Martin, was a major breakthrough in the treatment of chronic Hepatitis B. Prior to adefovir, Hepatitis B treatment was limited to two therapeutic modalities, either interferon, which carried significant side effects and was efficacious in a minority of patients, or lamivudine which showed no durable effects with short-term use and a high rate of resistance with long-term use. Adefovir was found to be effective in suppressing viral replication and in resolving the hepatic inflammation associated with hepatitis B with only rare instances of resistance. In this article, we appreciate John Martin’s contribution to science and medicine as we review the landmark trials of adefovir that brought forth a new era of treatment of Hepatitis B.

Insights Into the Coinfections of Human Immunodeficiency Virus-Hepatitis B Virus, Human Immunodeficiency Virus-Hepatitis C Virus, and Hepatitis B Virus-Hepatitis C Virus: Prevalence, Risk Factors, Pathogenesis, Diagnosis, and Treatment

Human immunodeficiency virus, hepatitis B virus, and hepatitis C virus are three blood-borne viruses that can cause major global health issues by increasing severe morbidity. There is a high risk of coinfection with these viruses in individuals because of their same transmission routes through blood using shared needles, syringes, other injection equipment, sexual transmission, or even vertical transmission. Coinfection can cause various liver-related illnesses, non-hepatic organ dysfunction, followed by death compared to any of these single infections. The treatment of coinfected patients is complicated due to the side effects of antiviral medication, resulting in drug resistance, hepatotoxicity, and a lack of required responses. On the other hand, coinfected individuals must be treated with multiple drugs simultaneously, such as for HIV either along with HBV or HCV and HBV and HCV. Therefore, diagnosing, treating, and controlling dual infections with HIV, HBV, or HCV is complicated and needs further investigation. This review focuses on the current prevalence, risk factors, and pathogenesis of dual infections with HIV, HBV, and HCV. We also briefly overviewed the diagnosis and treatment of coinfections of these three blood-borne viruses.

Chronic hepatitis B: New potential therapeutic drugs target

Chronic hepatitis B (CHB) infection remains the most causative agent of liver-related morbidity and mortality worldwide. It impacts nearly 300 million people. The current treatment for chronic infection with the hepatitis B virus (HBV) is complex and lacks a durable treatment response, especially hepatitis B surface antigen (HBsAg) loss, necessitating indefinite treatment in most CHB patients due to the persistence of HBV covalently closed circular DNA (cccDNA). New drugs that target distinct steps of the HBV life cycle have been investigated, which comprise inhibiting the entry of HBV into hepatocytes, disrupting or silencing HBV cccDNA, modulating nucleocapsid assembly, interfering HBV transcription, and inhibiting HBsAg release. The achievement of a functional cure or sustained HBsAg loss in CHB patients represents the following approach towards HBV eradication. This review will explore the up-to-date advances in the development of new direct-acting anti-HBV drugs. Hopefully, with the combination of the current antiviral drugs and the newly developed direct-acting antiviral drugs targeting the different steps of the HBV life cycle, the ultimate eradication of CHB infection will soon be achieved.

Tribute to John C. Martin at the Twentieth Anniversary of the Breakthrough of Tenofovir in the Treatment of HIV Infections

At Bristol-Myers (BM) (1985–1990), John C. Martin started his HIV career with directing the clinical development of didanosine (ddI) and stavudine (d4T). During this period, he became aware of the acyclic nucleoside phosphonates (ANPs), such as (S)-HPMPA and PMEA, as potential antiviral drugs. Under his impulse, BM got involved in the evaluation of these ANPs, but the merger of BM with Squibb (to become BMS) incited John to leave BM and join Gilead Sciences, and the portfolio of the ANPs followed the transition. At Gilead, John succeeded in obtaining the approval from the US FDA for the use of cidofovir in the treatment of cytomegalovirus (CMV) retinitis in AIDS patients, which was reminiscent of John’s first experience with ganciclovir (at Syntex) as an anti-CMV agent. At Gilead, John would then engineer the development of tenofovir, first as TDF (tenofovir disoproxil fumarate) and then as TAF (tenofovir alafenamide) and various combinations thereof, for the treatment of HIV infections (i), TDF and TAF for the treatment of hepatitis B (HBV) infections (ii), and TDF and TAF in combination with emtricitabine for the prophylaxis of HIV infections (iii).

Entecavir combined with interferon-α is superior to entecavir monotherapy in reducing hepatic and extrahepatic cancer in patients with chronic hepatitis B

BACKGROUND

The objective of this study was to assess whether entecavir (ETV) in combination with interferon-α (IFN-α) could reduce hepatocellular cancer (HCC) and extrahepatic cancers (EHCs) in patients with chronic hepatitis B (CHB).

METHODS

The cohort consisted of 4194 patients with CHB treated with ETV combined with IFN-α or ETV monotherapy at a tertiary hospital in Beijing, China, from January 2009 to December 2017. The risks, hazard ratios (HRs), and 95% confidence intervals (CIs) of HCC and EHCs were compared in the 2 groups.

RESULTS

In a multivariate Cox regression analysis, a significantly lower risk of HCC (HR, 0.6; 95% CI, 0.3-0.9; P = .0310) and a marginally significantly lower risk of EHCs (HR, 0.2; 95% CI, 0.02-1.3; P = .0854) were observed in the group receiving ETV combined with IFN-α in comparison with the ETV monotherapy group. The annual virological response rates were significantly higher in the combination therapy group versus the monotherapy group (33.8% vs 21.2%; P < .0001), but the hepatitis B surface antigen (HBsAg) seroclearance rates were not (1.2% vs 0.9%; P = .8537). The HRs were consistent with propensity score-based matching, inverse probability weighting adjustments, and adjustments for virological response and HBsAg seroclearance.

CONCLUSIONS

ETV combined with IFN-α therapy is superior to ETV monotherapy in reducing the risk of HCC and EHCs for patients with CHB. People who can tolerate and benefit from IFN-α therapy could consider combination therapy.

Amino Acid Polymorphism in Hepatitis B Virus Associated With Functional Cure

BACKGROUND & AIMS

To provide an adequate treatment strategy for chronic hepatitis B, it is essential to know which patients are expected to have a good prognosis and which patients do not require therapeutic intervention. Previously, we identified the substitution of isoleucine to leucine at amino acid 97 (I97L) in the hepatitis B core region as a key predictor among patients with stable hepatitis. In this study, we attempted to identify the point at which I97L affects the hepatitis B virus (HBV) life cycle and to elucidate the underlying mechanisms governing the stabilization of hepatitis.

METHODS

To confirm the clinical features of I97L, we used a cohort of hepatitis B e antigen-negative patients with chronic hepatitis B infected with HBV-I97 wild-type (wt) or HBV-I97L. The effects of I97L on viral characteristics were evaluated by in vitro HBV production and infection systems with the HBV reporter virus and cell culture-generated HBV.

RESULTS

The ratios of reduction in hepatitis B surface antigen and HBV DNA were higher in patients with HBV-I97L than in those with HBV-I97wt. HBV-I97L exhibited lower infectivity than HBV-I97wt in both infection systems with reporter HBV and cell culture-generated HBV. HBV-I97L virions exhibiting low infectivity primarily contained a single-stranded HBV genome. The lower efficiency of cccDNA synthesis was demonstrated after infection of HBV-I97L or transfection of the molecular clone of HBV-I97L.

CONCLUSIONS

The I97L substitution reduces the level of cccDNA through the generation of immature virions with single-stranded genomes. This I97L-associated low efficiency of cccDNA synthesis may be involved in the stabilization of hepatitis.

Fanconi syndrome induced by adefovir dipivoxil: a case report and clinical review

More than 150 cases of Fanconi syndrome (FS) or hypophosphatemia osteomalacia induced by low-dose adefovir dipivoxil (ADV) have been reported since 2002, when ADV was introduced for the long-term treatment of hepatitis B virus (HBV) infection. Because the life expectancy of HBV-infected individuals has increased, the adverse effects of long-term treatment with antiviral therapies are increasingly observed, and nephrotoxicity is one of the most severe adverse effects of ADV. Therefore, the number of cases may be far higher than reported. Moreover, ADV-induced FS is often misdiagnosed or diagnosed long after it first develops. ADV-induced FS may seriously decrease patient quality of life and lead to bone fractures and even disability. Although progress has been made in the identification of biomarkers and treatments, few systematic clinical guidelines or clinical reviews for FS induced by ADV have been reported. In this study, we highlighted the recent progress toward understanding of FS induced by ADV, described a clinical case, and summarized the primary characteristics and laboratory findings of this disease.

Follow-Up of Adefovir Dipivoxil Induced Osteomalacia: Clinical Characteristics and Genetic Predictors

Adefovir dipivoxil (ADV) is widely used for chronic hepatitis B therapy in China. To explore the clinical features and prognosis of ADV-induced osteomalacia and to analyze the association between osteomalacia and genetic variants in 51 drug transporters genes. Clinical and follow-up data of the ADV-treated patients were collected. Target capture sequencing was used to identify genetic variations of 51 drug transporter genes. A total of 193 hepatitis B patients treated with ADV were enrolled, of whom 140 had osteomalacia. The other 53 without osteomalacia were included in the control group. The median duration of ADV treatment before the onset of osteomalacia was 6.5 years (range:1.5–7 years). We found that most patients with osteomalacia had hypophosphatemia, high serum alkaline phosphatase levels, hypouricemia, nondiabetic glycosuria, proteinuria. Stopping ADV administration, supplementing calcitriol and calcium were effective treatments. During 3–6 months of follow-up, the clinical symptoms and biochemical indicators of patients with osteomalacia have been significantly improved. There was no significant difference in duration of adefovir treatment in patients with or without osteomalacia (p = 0.791). Through regression analysis, we found that age was a risk factor for osteomalacia [per 1 year, odds ratio (OR), 1.053; 95% confidence interval (95% CI), 1.020–1.087; p = 0.015]. 1992 single nucleotide variants were found using target capture sequencing. However, the associations of genetic variants of 51 drug transporter genes and the risk of osteomalacia were negligible. Osteomalacia is prone to occur in patients with chronic hepatitis B treated with long-term ADV at a therapeutic dose. After standard treatment, the prognosis is mostly good. We failed to find genetic variants that can predict the risk of ADV-induced osteomalacia.

Drug Discovery of Nucleos(t)ide Antiviral Agents: Dedicated to Prof. Dr. Erik De Clercq on Occasion of His 80th Birthday

Nucleoside and nucleotide analogues are essential antivirals in the treatment of infectious diseases such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus (HSV), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV). To celebrate the 80th birthday of Prof. Dr. Erik De Clercq on 28 March 2021, this review provides an overview of his contributions to eight approved nucleos(t)ide drugs: (i) three adenosine nucleotide analogues, namely tenofovir disoproxil fumarate (Viread^®) and tenofovir alafenamide (Vemlidy^®) against HIV and HBV infections and adefovir dipivoxil (Hepsera^®) against HBV infections; (ii) two thymidine nucleoside analogues, namely brivudine (Zostex^®) against HSV-1 and VZV infections and stavudine (Zerit^®) against HIV infections; (iii) two guanosine analogues, namely valacyclovir (Valtrex^®, Zelitrex^®) against HSV and VZV and rabacfosadine (Tanovea^®-CA1) for the treatment of lymphoma in dogs; and (iv) one cytidine nucleotide analogue, namely cidofovir (Vistide^®) for the treatment of HCMV retinitis in AIDS patients. Although adefovir dipivoxil, stavudine, and cidofovir are virtually discontinued for clinical use, tenofovir disoproxil fumarate and tenofovir alafenamide remain the most important antivirals against HIV and HBV infections worldwide. Overall, the broad-spectrum antiviral potential of nucleos(t)ide analogues supports their development to treat or prevent current and emerging infectious diseases worldwide.

What drives the dynamics of HBV RNA during treatment?

Hepatitis B virus RNA (HBV RNA)-containing particles are encapsidated pre-genomic RNA (pgRNA) detectable in chronically infected patients in addition to virions (HBV DNA) that have been suggested as a marker of the treatment efficacy. This makes promising the use of core protein allosteric modulators, such as RG7907, which disrupt the nucleocapsid assembly and profoundly reduce HBV RNA. Here, we developed a multiscale model of HBV extending the standard viral dynamic models to analyse the kinetics of HBV DNA and HBV RNA in 35 patients treated with RG7907 for 28 days. We compare the predictions with those obtained in patients treated with the nucleotide analog tenofovir. RG7907 blocked 99.3% of pgRNA encapsidation (range: 92.1%-99.9%) which led to a decline of both HBV DNA and HBV RNA. As a consequence of its mode of action, the first phase of decline of HBV RNA was rapid, uncovering the clearance of viral particles with half-life of 45 min. In contrast, HBV DNA decline was predicted to be less rapid, due to the continuous secretion of already formed viral capsids (t_1/2  = 17 ± 6 h). After few days, both markers declined at the same rate, which was attributed to the loss of infected cells (t_1/2  ≅ 6 ± 0.8 days). By blocking efficiently RNA reverse transcription but not its encapsidation, nucleotide analog in contrast was predicted to lead to a transient accumulation of HBV RNA both intracellularly and extracellularly. The model brings a conceptual framework for understanding the differences between HBV DNA and HBV RNA dynamics. Integration of HBV RNA in viral dynamic models may be helpful to better quantify the treatment effect, especially in viral-suppressed patients where HBV DNA is no longer detectable.

Overview of Biologically Active Nucleoside Phosphonates

The use of the phosphonate motif featuring a carbon-phosphorous bond as bioisosteric replacement of the labile P–O bond is widely recognized as an attractive structural concept in different areas of medicinal chemistry, since it addresses the very fundamental principles of enzymatic stability and minimized metabolic activation. This review discusses the most influential successes in drug design with special emphasis on nucleoside phosphonates and their prodrugs as antiviral and cancer treatment agents. A description of structurally related analogs able to interfere with the transmission of other infectious diseases caused by pathogens like bacteria and parasites will then follow. Finally, molecules acting as agonists/antagonists of P2X and P2Y receptors along with nucleotidase inhibitors will also be covered. This review aims to guide readers through the fundamentals of nucleoside phosphonate therapeutics in order to inspire the future design of molecules to target infections that are refractory to currently available therapeutic options.

Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Importance

A 2014 review for the US Preventive Services Task Force (USPSTF) found antiviral therapy for hepatitis B virus (HBV) infection associated with improved intermediate outcomes, although evidence on clinical outcomes was limited.

Objective

To update the 2014 HBV screening review in nonpregnant adolescents and adults to inform the USPSTF.

Data Sources

Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Ovid MEDLINE (2014 to August 2019); with surveillance through July 24, 2020.

Study Selection

Randomized clinical trials (RCTs) on screening and antiviral therapy; cohort studies on screening, antiviral therapy clinical outcomes, and the association between achieving intermediate outcomes after antiviral therapy and clinical outcomes.

Data Extraction and Synthesis

One investigator abstracted data; a second investigator checked accuracy. Two investigators independently assessed study quality. Random-effects profile likelihood meta-analysis was performed.

Results

Thirty trials and 20 cohort studies, with a total of 94 168 participants, were included. No study directly evaluated the effects of screening for HBV infection vs no screening on clinical outcomes such as mortality, hepatocellular carcinoma, or cirrhosis. Screening strategies that focused on risk factors such as ever having immigrated from high-prevalence countries and demographic and behavioral risk factors would identify nearly all HBV infection cases. In 1 study (n = 21 008), only screening immigrants from high-prevalence countries would miss approximately two-thirds of infected persons. Based on 18 trials (n = 2972), antiviral therapy compared with placebo or no treatment was associated with greater likelihood of achieving intermediate outcomes, such as virologic suppression and hepatitis B e-antigen (HBeAg) or hepatitis B surface antigen loss or seroconversion; the numbers needed to treat ranged from 2.6 for virologic suppression to 17 for HBeAg seroconversion. Based on 12 trials (n = 4127), first-line antiviral therapies were at least as likely as nonpreferred therapies to achieve intermediate outcomes. Based on 16 trials (n = 4809), antiviral therapy might be associated with improved clinical outcomes, but data were sparse and imprecise. Nine cohort studies (n = 3893) indicated an association between achieving an intermediate outcome following antiviral therapy and improved clinical outcomes but were heterogeneous (hazard ratios ranged from 0.07 to 0.87). Antiviral therapy was associated with higher risk of withdrawal due to adverse events vs placebo or no antiviral therapy.

Conclusions and Relevance

There was no direct evidence for the clinical benefits and harms of HBV screening vs no screening. Antiviral therapy for HBV infection was associated with improved intermediate outcomes and may improve clinical outcomes.

Investigation of the Structure and Dynamics of Antiviral Drug Adefovir Dipivoxil by Site-Specific Spin-Lattice Relaxation Time Measurements and Chemical Shift Anisotropy Tensor Measurements

Adefovir is regarded as a potential antiviral agent. However, it cannot be considered as a valuable drug candidate due to its high polarity that limits its permeability across the human intestinal mucosa. When the ribose phosphate group of adefovir is replaced by the isopolar phosphonomethyl ether functionality, it neutralizes the negative charge of the drug. This makes the drug lipid-soluble and potent to diffuse across the cell membrane. The prodrug adefovir dipivoxil is regarded as a potent antiviral drug against hepatitis B virus (HBV), human immunodeficiency virus (HIV), Rauscher murine leukemia virus (R-MuLV), murine cytomegalovirus (MCMV), herpes simplex virus (HSV), simian immunodeficiency virus (SIV), and feline immunodeficiency virus (FIV). The correlation between the structure and the dynamics of adefovir dipivoxil is determined by measuring the principal components of chemical shift anisotropy (CSA) tensor, site-specific spin-lattice relaxation time, and molecular correlation time at crystallographically different carbon nuclei sites. The CSA parameters, spin-lattice relaxation time, and molecular correlation time of phosphorous nucleus of the organophosphate group of adefovir dipivoxil molecule are also determined. The spin-lattice relaxation time of carbon nuclei varies from 1 to 107 s. The range of molecular correlation time also varies from 10-4 to 10-8 s. These remarkable diversities of motional dynamics of the molecules imply that there exist various motional degrees of freedom within this valuable drug and these motional degrees of freedom are independent of each other, which may be the reason for the biological activities exhibited by the drug. The correlation between structure and dynamics of such an important antiviral drug adefovir dipivoxil can be visualized by these types of extensive spectroscopic measurements, which will enlighten the path of inventing advanced medicine in the pharmaceutical industry, and it will also illuminate the understanding of the structure-activity relationships of antiviral drug.

Long-term virological and adherence outcomes to antiviral treatment in a 4-year cohort chronic HBV study

BACKGROUND

Chronic hepatitis B (CHB) treatment adherence has been poorly studied worldwide. We evaluated long-term virological and adherence outcomes to antiviral treatment in CHB patients.

METHODS

A prospective 183 Brazilian CHB patient cohort treated with monotherapy or combination adefovir dipivoxil, entecavir, lamivudine and/or tenofovir disoproxil fumarate was studied in a reference tertiary centre. Treatment adherence was evaluated by a validated questionnaire named 'Assessment of Adherence to Antiviral Therapy Questionnaire' (CEAT-HBV) within three yearly periods (2010/2011, 2013/2014 and 2014/2015).

RESULTS

CEAT-HBV identified 43% (79/183) patients with non-adherence to antiviral treatment and among them, 67% (53/79) were viral load positive. The main causes associated with non-response to antiviral treatment were drug resistance variants followed by non-adherence, insufficient treatment duration and other causes. Single-dose pharmacokinetics demonstrated 35% (23/65) antiviral non-adherence. 2 years after the first assessment, the CEAT-HBV indicated that 71% (101/143) of subjects adhered to treatment (per-protocol population). However, 21% (40/183) of the patients could not be evaluated and were excluded. The main reasons for exclusion were death (20/183), 11 out 20 deaths due to hepatocellular carcinoma. HBV booklet was used for medical education. The third CEAT-HBV assessment (2014/2015) showed that 83% (112/135) patients were compliant with treatment adherence (per-protocol population). Long-term evaluation showed that adherence rate based on CEAT-HBV continue to increase after 4-years (P<0.001).

CONCLUSIONS

The results highlight the importance of CHB therapy adherence assessment monitoring. Long-term adherence outcomes were dynamic and it is possible to increase the migration rate to adherence/HBV-DNA-negative group.

A comparative network meta-analysis of standard of care treatments in treatment-naïve chronic hepatitis B patients

Objective: Published network meta-analyses of chronic hepatitis B (CHB) treatments are either out-of-date or excluded key treatments. Therefore, we aimed to comprehensively update the efficacy evidence for the following end points: Hepatitis B surface antigen (HBsAg) loss, hepatitis B early antigen (HBeAg) seroconversion and hepatitis B virus DNA (HBV DNA) suppression. Materials & methods: Approved treatments in CHB and their combinations were evaluated. A systematic literature review was conducted to identify all randomized controlled trials in treatment-naïve CHB patients. Included studies reported at least one of the end points of interest. A frequentist probability network meta-analysis was performed for each end point. The choice of fixed effect or random-effect model was based on the I-square statistic, a measure of variation in study outcomes between studies. The analyses were performed separately for HBeAg-positive and HBeAg-negative patients. For the primary analyses, end points measured 48 ± 4 weeks after treatment initiation were considered. Results: A total of 47 randomized controlled trials (13,826 patients), covering 23 unique treatment regimens, were included: a total of 29 reported HBsAg loss, 36 reported HBeAg seroconversion and 37 reported HBV DNA suppression. For both HBsAg loss and HBeAg seroconversion, pegylated interferon-based regimens were the most effective strategy in both HBeAg-positive and HBeAg-negative patients. On the other hand, for HBV DNA suppression, nucleosides-based regimens were the most effective strategy in both HBeAg-positive and HBeAg-negative patients. Conclusion: Our findings confirm available evidence around the comparative efficacy of available CHB treatments. Therefore, they can be used to update relevant cost-effectiveness analyses and clinical guidelines.

HBx increases EGFR expression by inhibiting miR129-5p function

Despite the efficient suppression of hepatitis B virus (HBV) replication by nucelos(t)ide analogs, HBV RNA expression usually continues even during nucleots(t)ide analog therapy because episomal covalently closed circular DNA (ccDNA), which is the template for HBV RNA transcription, cannot be eliminated. Here, we found that the common sequences of all HBV RNAs and that encoding the X protein (HBx) have similarities with the sequences of a host cellular microRNA (miRNA), miR129-5p. HBx inhibits miR129-5p function, resulting in increased expression of ZBTB20, a target gene of miR129-5p. ZBTB20 activates transcription and increases cell-surface epidermal growth factor receptor (EGFR) levels, promoting the cell growth rate, and this effect was reversed through ZBTB20 knockdown. mir129-5p levels in Ago2-containing complexes were reduced by expression of HBx, suggesting that the viral RNA sequestered miR129-5p from Ago2-containing complexes. These results indicate the possibility that HBV RNA may maintain pathogenicity even through nucleos(t)ide analog therapy.

Stabilized oral nanostructured lipid carriers of Adefovir Dipivoxil as a potential liver targeting: Estimation of liver function panel and uptake following intravenous injection of radioiodinated indicator

PURPOSE

Adefovir dipivoxil (AD), a nucleoside reverse transcriptase inhibitor is effective against Hepatitis B virus. Its poor oral bioavailability leads to frequent administration causing severe adverse effects. Thereby the entrapment of AD within lipid nanoparticulate systems is a way of increasing AD oral bioavailability as a result of improving intestinal permeability with efficient liver-targeted delivery together with higher drug stability during storage.

METHODS

AD-loaded nanostructured lipid carriers (AD-NLCs) were prepared via solvent emulsification diffusion technique adopting 2⁴ full factorial design to study the effect of lipid percentage, presence of egg yolk lecithin, surfactant type and percentage on entrapment efficiency (E.E.%), particle size and percent in-vitro drug released after 8 h (Q8hrs).

RESULTS

Formula (F12) showed E.E.% of 90.5 ± 0.2%, vesicle size of 240.2 ± 2.5 nm and Q8hrs of 58.55 ± 9.4% was selected as the optimum formula with desirability value of 0.757 based on highest EE%, lowest P.S. and Q8hrs. Further evaluation of the optimized formula using radioiodinated rose bengal (RIRB) in thioacetamide induced liver damage in Swiss Albino mice revealed a higher liver uptake of 22 ± 0.01% ID/g (percent injected dose/g organ) and liver uptake/Blood (T/B) ratio of 2.22 ± 0.067 post 2 h of I.V injection of RIRB compared to 9 ± 0.01% ID/g and 0.64 ± 0.017 in untreated group, respectively.

CONCLUSION

NLCs could be successfully used as oral drug delivery carriers of the antiviral drug Adefovir Dipivoxil to the liver with higher stability and oral bioavailability. Graphical abstract.

Hepatitis B virus recurrence after liver transplantation: An old tale or a clear and present danger?

Hepatitis B virus (HBV) recurrence after liver transplantation (LT) has been described more than 50 years ago. Similarly, to other clinical conditions, in which impairment of host immune defense favors viral replication, early reports described in details recurrence and reactivation of HBV in liver transplant recipients. The evidence of a possible, severe, clinical evolution of HBV reappearance in a significant percentage of these patients, allowed to consider, for some years, HBV positivity a contraindication for LT. Moving from the old to the new millennium this picture has changed dramatically. Several studies contributed to establish efficient prophylactic protocols for HBV recurrence and with the advent of more potent anti-viral drugs an increased control of infection was achieved in transplanted patients as well as in the general immune-competent HBV population. Success obtained in the last decade led some authors to the conclusion that HBV is now to consider just as a “mere nuisance”. However, with regard to HBV and LT, outstanding issues are still on the table: (1) A standard HBV prophylaxis protocol after transplant has not yet been clearly defined; (2) The evidence of HBV resistant strains to the most potent antiviral agents is claiming for a new generation of drugs; and (3) The possibility of prophylaxis withdrawal in some patients has been demonstrated, but reliable methods for their selection are still lacking. The evolution of LT for HBV is examined in detail in this review together with the description of the strategies adopted to prevent HBV recurrence and their pros and cons.

Persistence and adherence to nucleos(t)ide analogues in chronic hepatitis B: a multicenter cohort study

BACKGROUND

Adherence and persistence to long-term therapy with nucleos(t)ides analogues are crucial to the outcome of treatment in chronic hepatitis B. Our aim was to determine the persistence and adherence rates to nucleos(t)ides analogues in chronic hepatitis B patients under maintenance therapy and to identify relative to prediction of adherence factors.

METHODS

We retrospectively analyzed electronic prescription data of patients (2011-2016; n = 400) with chronic hepatitis B treated with nucleos(t)ides analogues at 4 tertiary liver centers in Greece.

RESULTS

Two hundred ninety-six of 400 patients were under or initiated treatment in 2011-2012 (existing patients), while the remainder initiated or switched medication from January 2013 and onward (new patients). The median adherence rate was 99%, with 89.7% achieving adherence >80% during a mean follow-up of 28 ± 14 months. The overall 12-month persistence rate was 57%, with no difference between patients receiving tenofovir, entecavir or double therapy (57.8%, 52.8% and 68.4%, respectively, P = 0.399). The decline in persistence was more pronounced during the first 3 months of follow-up and in existing patients (P = 0.057). Overall, 80% and 55.1% of nonpersistent patients succeeded adherence to nucleos(t)ides analogues >80% and >90%, respectively. Multivariate analyses showed that existing (vs. new) patients were less likely to have >80% adherence (odds ratio: 0.324, P = 0.44) and persistence (odds ratio: 0.562, P = 0.057) to nucleos(t)ides analogues therapy.

CONCLUSION

In this real-world cohort of chronic hepatitis B patients, high adherence to nucleos(t)ides analogues was coupled with suboptimal persistence with prescribing the medication. Our data indicate that persistence and adherence are distinct measures that should be approached separately in educational programs targeting to improve medication-taking behavior in chronic hepatitis B.

Trends in chronic hepatitis B treatment-related research from 1973 to 2018: a bibliometric and visual analysis

OBJECTIVE

Chronic hepatitis B (CHB) is a worldwide disease and the most common cause of liver cancer. This study aimed to identify specific areas of research activity concerning CHB treatment between 1973 and 2018 and to aid in identifying new areas for future development.

METHODS

The literature was searched from the GoPubMed and Web of Science databases using terms related to CHB treatment, analyzed with bibliometric methods and visualized using VOSviewer.

RESULTS

A total of 9486 and 5883 papers were collected from PubMed and Web of science, respectively. The studies focused on two clusters of topics: antiviral therapy for CHB and progressive diseases, and drug resistance. Studies related to antiviral drugs concentrated on lamivudine (n = 788), entecavir (n = 390), and adefovir dipivoxil (n = 376). Studies addressing conditions developing from CHB highlighted hepatocellular carcinoma (n = 403) and cirrhosis (n = 223). China (n = 1978) contributed the most publications. The 10 most quantitatively prolific organizations were in France. All 20 of the most cited papers investigated antiviral treatments for CHB or CHB-associated cirrhosis.

CONCLUSIONS

Research on CHB treatment over the past 45 years has concentrated on antiviral therapy, CHB-associated progressive conditions, drug resistance and immunization. Although work on CHB treatment has made considerable progress, new approaches must be explored.

Hepatitis B-related glomerulonephritis and optimization of treatment

Introduction: Multiple studies have revealed a strong relationship between the development of nephropathy and hepatitis B virus (HBV) infection. The underlying pathogenesis of hepatitis B-related glomerulonephritis (HBV-GN) involves immune complexes, which can be isolated from kidney tissues. Clearance of HBV antigenemia improves renal impairment and proteinuria in HBV-GN patients.Areas covered: In this review, we present our current understanding of the epidemiology, pathogenesis, pathology, diagnosis, and treatment of HBV-GN. We discuss the advantages and disadvantages of oral nucleoside/nucleotide analogs (NAs), and the main pharmaceutical treatment for hepatis B.Expert opinion: Currently, antiviral agents are the main HBV-GN therapeutic agents. Although no randomized controlled clinical trials have compared the efficacy of interferon (IFN) and NA, we suggest IFN treatment for pediatric patients (IFN-α in patients ≥1 year; pegIFN-α in patients ≥3 years) considering treatment duration and absence of resistance. Novel NAs have brought about promising treatment options involving high efficacy viral suppression and low resistance rates. NAs with a high barrier to resistance (e.g. entecavir) are recommended as first-line therapy of HBV-GN. Immunosuppression monotherapy, such as corticosteroids, is of little benefit and potentially harmful to HBV-GN patients due to the possibility of viral reactivation.

Bayesian Network Meta-Analysis for Assessing Adverse Effects of Anti-hepatitis B Drugs

BACKGROUND AND OBJECTIVE

Oral nucleoside/nucleotide analogues (NAs) have been advocated for chronic hepatitis B (CHB) treatment with good efficacy. However, less attention has been put on their adverse events. Therefore, a Bayesian network meta-analysis (NMA) was performed to evaluate the relative safety of five NAs (lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate) in CHB treatment among adults.

METHODS

Eligible randomized clinical trials (RCTs) and prospective cohort studies were systematically and thoroughly searched until May 1, 2019. Poisson-prior-based Bayesian NMA was performed to synthesize both direct and indirect evidence with reporting hazard ratios (HRs) and 95% credible intervals (CrIs) for serious adverse events (SAEs) and hepatic/renal impairments.

RESULTS

Thirty-three RCTs and 11 prospective cohort studies were identified. As to SAEs, no statistically significant difference was found of any comparison among five NAs. In terms of hepatotoxicity, lamivudine was safer than telbivudine (HR 0.45; 95% CrI 0.21, 0.85), and entecavir increased the risk by 102% (entecavir vs lamivudine: HR 2.02; 95% CrI 1.19, 3.27).

CONCLUSIONS

The findings from this large NMA could influence clinical practice, and the methodological framework of this study could provide evidence-based support to analyze sparse safety data in the field.

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.

Sustained antiviral effects and clearance of hepatitis surface antigen after combination therapy with entecavir and pegylated interferon in chronic hepatitis B

BACKGROUND

Although the efficacy of combination therapy with lamivudine or tenofovir and pegylated interferon (PEG-IFN) has been reported in patients with chronic hepatitis B (CHB), the long-term effect of the combination based on the observation of clinical course remains to be clarified. We previously reported the efficacy of combination therapy with entecavir (ETV) and PEG-IFN. Here, we investigated the long-term effect of this combination in patients with CHB.

METHODS

We administered both ETV and PEG-IFN-α2a or -2b simultaneously to 26 patients with HBV genotype C infection. Treatment was continued for 48 weeks followed by 24 weeks of observation period; we examined the virological and biochemical responses. We also analysed characteristics related to the post-treatment relapse. Finally, we investigated the long-term therapeutic effects.

RESULTS

Average reduction of intra-hepatic cccDNA level was 1.2 log copies/μg at the completion of administration. Pretreatment hepatitis B surface antigen (HBsAg) level with more than 3.5 log U/ml was identified as a predictive factor for relapse. Furthermore, the cumulative rates of HBsAg-negative patients at 1, 3 and 5 years after the completion of administration were 3.8, 8.4 and 15%, respectively (mean follow-up period: 4.8 years).

CONCLUSIONS

Baseline HBsAg level with more than 3.5 log U/ml is a useful predictor for relapse 24 weeks after the completion of administration in patients treated with combination therapy. Combination with ETV and PEG-IFN could be an option for treatment of CHB patients especially in those with baseline HBsAg levels of less than 3.5 log U/ml.

Antiviral treatment for treatment-naïve chronic hepatitis B: systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Chronic hepatitis B (CHB) infection poses a significant burden to public health worldwide. Most cases are clinically silent until late in the disease course. The main goal of current therapy is to improve survival and quality of life by preventing disease progression to cirrhosis and liver failure, and consequently hepatocellular carcinoma development. The objective of this review is to provide a contemporary and comprehensive evaluation of the effectiveness of treatment options.

METHODS

We performed a systematic review of peer-reviewed literature for randomized controlled trials involving treatment-naïve CHB adult population who received antiviral therapy. The endpoints were virologic response (VR), normalization of alanine aminotransferase (ALT norm), HBeAg loss, HBeAg seroconversion, and HBsAg loss for the HBeAg-positive population; and VR and ALT norm for the HBeAg-negative population. Network meta-analysis (NMA) was performed to synthesize evidence on the efficacy of treatment.

RESULTS

Forty-two publications were selected. Twenty-three evaluated HBeAg-positive population, 13 evaluated HBeAg-negative population, and six evaluated both. We applied NMA to the efficacy outcomes of the two populations separately. Treatment strategies were ranked by the probability of achieving outcomes, and pairwise comparisons calculated from NMA were reported in odds ratios (OR). For HBeAg-positive population, tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) were the best for VR; OR vs adefovir = 14.29, 95% CI 7.69-25 and 12.5, 95% CI 4.35-33.33 respectively. TAF was the best for achieving ALT norm (OR vs placebo = 12.5, 95% CI 4.55-33.33), HBeAg loss, and seroconversion (OR vs entecavir/TDF combination = 3.03, 95% CI 1.04-8.84 and 3.33, 95% CI 1.16-10 respectively). In the HBeAg-negative population, TDF and TAF were the best for VR (OR vs adefovir = 9.79, 95% CI 2.38-42.7 and 11.71, 95% CI 1.03-150.48 respectively). Telbivudine and TAF were the best for ALT norm. Certain nucleos(t)ide combinations also had high probability of achieving positive outcomes.

CONCLUSIONS

Our results are consonant with current clinical guidelines and other evidence reviews. For both HBeAg-positive and HBeAg-negative populations, TDF and TAF are the most effective agents for virologic suppression, and TAF is effective across all outcomes.

Changes in APRI and FIB-4 in HBeAg-negative treatment-naive chronic hepatitis B patients with significant liver histological lesions receiving 5-year entecavir therapy

According to guidelines, antiviral therapy for adults with immune-active chronic hepatitis B (CHB) should be adopted to decrease the risk of liver-related complications. Fibrosis assessment during antiviral treatment is a key step in antiviral therapy evaluation. Liver biopsy is the gold standard for assessing the degree of liver necroinflammation and fibrosis. However, because of its cost and the risk of life-threatening complications, performing a liver biopsy more than once after long-term effective treatment is difficult. In this study, we aimed to evaluate changes in liver fibrosis during 5 years of entecavir (ETV) treatment using noninvasive fibrosis markers in hepatitis B e-antigen (HBeAg)-negative treatment-naive CHB patients who require antiviral therapy. A total of 303 HBeAg-negative treatment-naive patients were enrolled in this study. Liver biopsy was performed before initiation of antiviral therapy. The diagnosis of CHB was made according to Chinese guidelines for the management of CHB. Patients requiring antiviral therapy (liver fibrosis stage ≥ F2, METAVIR scoring system) were treated with ETV for at least 5 years. These patients were followed up at 6-month intervals. A clinical and virological evaluation was performed at baseline and again at 12, 24, 36, 48, and 60 months during ETV treatment. Aspartate Aminotransferase to Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4) index were used to assess dynamic changes in liver fibrosis in HBeAg-negative CHB patients after 1, 2, 3, 4, and 5 years of ETV treatment. All enrolled patients underwent liver biopsy at baseline. Using the METAVIR fibrosis stages, there were 107, 125, 54, and 17 patients in F1, F2, F3, and F4 stages, respectively. The APRI and FIB-4 indexes enabled the correct identification of patients with severe fibrosis (METAVIR F3-F4), with an area under the receiver operating characteristic curve of 0.77 (95% confidence interval [CI] 0.72-0.83) and 0.76 (95% CI 0.70-0.82), respectively. The APRI values decreased significantly in F2 and F3 patients after 1 year of ETV therapy (P < 0.01). However, for F4 patients, APRI values decreased significantly at year 3 (P < 0.05). The FIB-4 values of F2, F3, and F4 patients who received ETV treatment were significantly decreased after 1, 3, and 5 years of ETV therapy, respectively (P < 0.05). APRI and FIB-4 values decreased significantly during 5-year ETV treatment in HBeAg-negative CHB patients, indicating that these noninvasive fibrosis tests might be useful for monitoring improvement in liver fibrosis and assessing treatment efficacy during long-term ETV treatment.

Control of replication of hepatitis B and C virus improves patient and graft survival in kidney transplantation

BACKGROUND & AIMS

Before antiviral therapy, kidney transplant recipients infected with hepatitis B virus (HBV) or hepatitis C virus (HCV) had poor outcomes. Since the 90s, nucleos(t)ide analogues have been widely used in HBV-infected patients, while interferon-based therapy was rarely used in HCV-infected patients. The aim of this study was to assess the impact of HBV and HCV on patient and graft survival, according to viral replication status.

METHODS

Data from January 1993 to December 2010 were extracted from the French national database CRISTAL. A total of 31,433 kidney transplant recipients were included, of whom 575, 1,060 and 29,798 had chronic hepatitis B, C, or were not infected, respectively.

RESULTS

Ten-year survival was lower in HCV-infected (71.3%) than in HBV-infected (81.2%, p = 0.0004) or non-infected kidney transplant recipients (82.7%, p <0.0001). Ten-year kidney graft survival was lower in HCV-infected (50.6%) than in HBV-infected (62.3%, p <0.0001) or non-infected kidney transplant recipients (64.7%, p <0.0001). A random analysis of the medical records of 184 patients with HBV and 504 patients with HCV showed a control of viral replication in 94% and 35% of cases, respectively. Ten-year patient and graft survival in patients with detectable HCV RNA was lower than in their matching controls. Conversely, patients with HCV and undetectable HCV RNA had higher 10-year survival than their matched controls without significant differences in graft survival.

CONCLUSIONS

Chronic HBV infection does not impact 10-year patient and kidney graft survival thanks to control of viral replication with nucleos(t)ide analogues. In kidney transplant recipients infected with HCV, patients with detectable RNA had worse outcomes, whereas the outcomes of those with undetectable RNA were at least as good as non-infected patients. Thus, direct-acting antivirals should be systematically offered to HCV-infected patients.

LAY SUMMARY

Previously, infections with hepatitis B or hepatitis C virus led to poor outcomes in kidney transplant recipients. However, the outcomes of kidney transplants in patients with viral suppression are as good as those for kidney transplants in non-infected patients. Antiviral therapy should be systematically proposed to hepatitis B and/or hepatitis C-infected kidney transplant recipients or candidates to prevent the deleterious hepatic and extrahepatic impact of chronic viral replication. Recent access to direct-acting antivirals in patients with hepatitis C virus and renal dysfunction provides exciting new opportunities.

Plasmodium Purine Metabolism and Its Inhibition by Nucleoside and Nucleotide Analogues

Malaria still affects around 200 million people and is responsible for more than 400,000 deaths per year, mostly children in subequatorial areas. This disease is caused by parasites of the Plasmodium genus. Only a few WHO-recommended treatments are available to prevent or cure plasmodial infections, but genetic mutations in the causal parasites have led to onset of resistance against all commercial antimalarial drugs. New drugs and targets are being investigated to cope with this emerging problem, including enzymes belonging to the main metabolic pathways, while nucleoside and nucleotide analogues are also a promising class of potential drugs. This review highlights the main metabolic pathways targeted for the development of potential antiplasmodial therapies based on nucleos(t)ide analogues, as well as the different series of purine-containing nucleoside and nucleotide derivatives designed to inhibit Plasmodium falciparum purine metabolism.

Hypophosphatemic Osteomalacia Associated with Adefovir-induced Fanconi Syndrome Initially Diagnosed as Diabetic Kidney Disease and Vitamin D Deficiency

A 68-year-old man with type 2 diabetes mellitus and chronic hepatitis B infection was referred to the nephrology department before planned surgery for hepatocellular carcinoma. He had been receiving low-dose adefovir dipivoxil (ADV) for 11 years. Laboratory findings revealed impaired re-absorption in the proximal renal tubules. He had been diagnosed with diabetic kidney disease and osteomalacia due to vitamin D deficiency; thus, ADV was not discontinued until he was referred to us. In this case, concomitant diabetes mellitus and vitamin D deficiency might have prevented the early diagnosis of ADV-induced Fanconi syndrome.

Alpha-carboxynucleoside phosphonates: direct-acting inhibitors of viral DNA polymerases

Acyclic nucleoside phosphonates represent a well-defined class of clinically used nucleoside analogs. All acyclic nucleoside phosphonates need intracellular phosphorylation before they can bind viral DNA polymerases. Recently, a novel class of alpha-carboxynucleoside phosphonates have been designed to mimic the natural 2'-deoxynucleotide 5'-triphosphate substrates of DNA polymerases. They contain a carboxyl group in the phosphonate moiety linked to the nucleobase through a cyclic or acyclic bridge. Alpha-carboxynucleoside phosphonates act as viral DNA polymerase inhibitors without any prior requirement of metabolic conversion. Selective inhibitory activity against retroviral reverse transcriptase and herpesvirus DNA polymerases have been demonstrated. These compounds have a unique mechanism of inhibition of viral DNA polymerases, and provide possibilities for further modifications to optimize and fine tune their antiviral DNA polymerase spectrum.

Tumor DNA-dependent protein kinase catalytic subunit expression is associated with hepatitis B surface antigen status and tumor progression in patients with hepatocellular carcinoma

The DNA-dependent protein kinase catalytic subunit (DNA-PKcs), which plays an important role in the DNA damage response, has been reported to be associated with tumor progression in various carcinomas. However, the clinical significance of DNA-PKcs in hepatocellular carcinoma (HCC) patients remains unclear. In the present study, we determined the tumor expression of DNA-PKcs in 104 resected HCC specimens by immunohistochemistry. The DNA-PKcs expression was scored as follows; 0, negative staining; 1, staining of nuclei at the tumor edge; 2, staining of the nuclei deep within the tumor and/or the tumor cytoplasm. The relationships between tumor expression of DNA-PKcs and the clinical characteristics and patient outcomes were investigated. Among the 104 HCCs, the distribution of staining for DNA-PKcs was as follows: 32 tumors were assigned a score of 0, 27 tumors were assigned a score of 1, and 45 tumors were assigned a score of 2. Statistical analyses revealed that tumor DNA-PKcs expression was significantly associated with the HBs antigen (HBsAg) status, presence/absence of portal vein invasion, size of the largest tumor nodule (<3.0 cm/>3.0, cm), and the serum alpha-fetoprotein level. Significant differences in the overall survival and recurrence-free survival were observed between patients showing (staining score 1 or 2) and not showing (staining score 0) tumor DNA-PKcs expression (P = 0.049 and P = 0.045, respectively). Our results suggest that tumor expression of DNA-PKcs is associated with tumor progression, HBsAg status and the postoperative outcomes in patients with HCC.

Adefovir-induced Fanconi syndrome associated with osteomalacia

Fanconi syndrome is a dysfunction of the proximal renal tubules that results in impaired reabsorption and increased urinary loss of phosphate and other solutes. The pathophysiology of drug-induced Fanconi syndrome is unclear. Here we report the case of a 36-year-old woman who presented with pain in multiple bones and proteinuria. She had a 7-year history of taking adefovir at 10 mg/day for chronic hepatitis B. Three years previously she had received surgery for a nontraumatic right femur neck fracture, after which she continued to complain of pain in multiple bones, and proteinuria, glycosuria, and phosphaturia were noted. The findings of a light-microscope examination of a renal biopsy sample were normal, but mitochondrial damage of the proximal tubules was evident in electron microscopy. Western blot analysis revealed that the level of serum fibroblast growth factor 23 (FGF23) was lower than in normal controls. After 2 months of treatment, hypophosphatemia and proximal tubular dysfunction were reversed, and serum FGF23 had normalized. This case suggests that direct mitochondrial damage in proximal tubules can cause drug-induced Fanconi syndrome associated with osteomalacia.

The evolution of nucleoside analogue antivirals: A review for chemists and non-chemists. Part 1: Early structural modifications to the nucleoside scaffold

This is the first of two invited articles reviewing the development of nucleoside-analogue antiviral drugs, written for a target audience of virologists and other non-chemists, as well as chemists who may not be familiar with the field. Rather than providing a simple chronological account, we have examined and attempted to explain the thought processes, advances in synthetic chemistry and lessons learned from antiviral testing that led to a few molecules being moved forward to eventual approval for human therapies, while others were discarded. The present paper focuses on early, relatively simplistic changes made to the nucleoside scaffold, beginning with modifications of the nucleoside sugars of Ara-C and other arabinose-derived nucleoside analogues in the 1960's. A future paper will review more recent developments, focusing especially on more complex modifications, particularly those involving multiple changes to the nucleoside scaffold. We hope that these articles will help virologists and others outside the field of medicinal chemistry to understand why certain drugs were successfully developed, while the majority of candidate compounds encountered barriers due to low-yielding synthetic routes, toxicity or other problems that led to their abandonment.

Chronic Hepatitis B Infection: A Review

IMPORTANCE

More than 240 million individuals worldwide are infected with chronic hepatitis B virus (HBV). Among individuals with chronic HBV infection who are untreated, 15% to 40% progress to cirrhosis, which may lead to liver failure and liver cancer.

OBSERVATIONS

Pegylated interferon and nucleos(t)ide analogues (lamivudine, adefovir, entecavir, tenofovir disoproxil, and tenofovir alafenamide) suppress HBV DNA replication and improve liver inflammation and fibrosis. Long-term viral suppression is associated with regression of liver fibrosis and reduced risk of hepatocellular carcinoma in cohort studies. The cure (defined as hepatitis B surface antigen loss with undetectable HBV DNA) rates after treatment remain low (3%-7% with pegylated interferon and 1%-12% with nucleos[t]ide analogue therapy). Pegylated interferon therapy can be completed in 48 weeks and is not associated with the development of resistance; however, its use is limited by poor tolerability and adverse effects such as bone marrow suppression and exacerbation of existing neuropsychiatric symptoms such as depression. Newer agents (entecavir, tenofovir disoproxil, and tenofovir alafenamide) may be associated with a significantly reduced risk of drug resistance compared with older agents (lamivudine and adefovir) and should be considered as the first-line treatment.

CONCLUSIONS AND RELEVANCE

Antiviral treatment with either pegylated interferon or a nucleos(t)ide analogue (lamivudine, adefovir, entecavir, tenofovir disoproxil, or tenofovir alafenamide) should be offered to patients with chronic HBV infection and liver inflammation in an effort to reduce progression of liver disease. Nucleos(t)ide analogues should be considered as first-line therapy. Because cure rates are low, most patients will require therapy indefinitely.

DHX9 regulates production of hepatitis B virus-derived circular RNA and viral protein levels

Hepatitis B virus (HBV) infection, which is a major health concern worldwide, can lead to liver cirrhosis and hepatocellular carcinoma. Although current nucleos(t)ide analogs efficiently inhibit viral reverse transcription and viral DNA load clinically, episomal viral covalently closed circular DNA (cccDNA) minichromosomes and transcripts from cccDNA continue to be expressed over the long term. We hypothesized that, under these conditions, viral transcripts may have biological functions involved in pathogenesis. Here, we show that the host protein DExH-box helicase 9 (DXH9) is associated with viral RNAs. We also show that viral-derived circular RNA is produced during HBV replication, and the amount is increased by knockdown of the DHX9 protein, which, in turn, results in decreased viral protein levels but does not affect the levels of HBV DNA. These phenomena were observed in the HBV-producing cell culture model and HBV mini-circle model mimicking HBV cccDNA, as well as in human primary hepatocytes infected with HBV. Based on these results, we conclude that, in HBV infection, the RNA binding factor DHX9 is a novel regulator of viral circular RNA and viral protein levels.

Toward a Cure for Hepatitis B Virus Infection: Combination Therapy Involving Viral Suppression and Immune Modulation and Long-term Outcome

Chronic hepatitis B virus (HBV) infection remains a major global health burden. Currently, the approved therapeutic regimens include nucleos(t)ide analogues (NAs) and either interferon or pegylated interferon. NA therapy is generally safe and well tolerated, but the rate of posttreatment virologic relapse is high, making NA treatment a lifetime commitment. The benefits of pegylated interferon treatment include a finite duration, more-durable response and absence of viral resistance. However, sustained response to interferon alone is achieved only in a minority of patients, and side effects are common, which limit its clinical use. Given that HBV covalently closed circular DNA and the integrated HBV genome persist stably in the nuclei of infected hepatocytes, elimination (complete cure) of HBV is rarely achieved. After completion of treatment, sustained HBV surface antigen loss, with or without seroconversion to HBV surface antibody positivity (ie, functional cure), is therefore recommended as the ideal end point for anti-HBV treatment, despite the lack of complete eradication of HBV. Theoretically, combination of antiviral agents with differential mechanisms of actions on HBV, including viral suppression combined with immune modulation (as occurs during treatment with NA plus pegylated interferon), is an encouraging strategy to treat chronic hepatitis B. Recent studies have confirmed certain virological and serological advantages of simultaneous administration of NA and pegylated interferon (de novo combination therapy) or addition of pegylated interferon to ongoing NA therapy (sequential combination therapy) over monotherapy. Few data exist, however, on the long-term outcomes of patients receiving combination therapy. This review summarizes current combination therapy developed to cure chronic HBV infection.

Baracle® vs Baraclude® for 48 weeks in patients with treatment-naïve chronic hepatitis B: a comparison of efficacy and safety

Background and objective

Entecavir (ETV) is a standard of care for chronic hepatitis B (CHB). In a bioequivalence study, ETV from Dong-A ST (Baracle^®) was found to have a pharmacokinetic profile equivalent to ETV from Bristol-Myers Squibb (BMS) (Baraclude^®). The present study was conducted to evaluate the antiviral activity and safety of ETV from Dong-A ST in comparison to ETV from BMS in patients with CHB.

Methods

In this multicenter, double-blind, active-controlled, stratified-randomized, parallel group, comparative trial, 118 treatment-naïve patients with CHB were randomly assigned to receive either 0.5 mg of ETV from Dong-A ST or ETV from BMS once daily for 48 weeks. The primary efficacy endpoint was virologic improvement (a mean reduction from baseline in serum HBV DNA levels) at 24 weeks. Secondary efficacy endpoints included a mean reduction in serum HBV DNA levels at 48 weeks, proportion of patients with undetectable levels of serum HBV DNA, rates of hepatitis B e antigen (HBeAg) loss and seroconversion, rates of HBsAg loss and seroconversion, and rates of normalization of alanine aminotransferase (ALT) levels.

Results

From baseline to week 24, HBV DNA levels (log₁₀) decreased by 4.81 and 4.63 with ETV from Dong-A ST and with ETV from BMS, respectively. The upper limit of two-sided 95% confidence intervals (CI) (equivalent to one-sided 97.5% CIs) for the difference between the treatment groups was 0.208, which was below the noninferiority margin of 1, thus supporting the noninferiority of ETV from Dong-A ST in comparison to ETV from BMS. No statistically significant differences were noted between the treatment groups in all secondary and tertiary efficacy endpoints. Safety profiles were also similar between the two groups.

Conclusion

In patients with previously untreated HBeAg-positive or negative HBV infection, the efficacy of ETV from Dong-A ST was noninferior to that of ETV from BMS, and there were no significant differences in efficacy or safety between two groups.

Adefovir dipivoxil loaded proliposomal powders with improved hepatoprotective activity: formulation, optimization, pharmacokinetic, and biodistribution studies

The present study aimed to prepare proliposomal formulae for improving the oral bioavailability of adefovir dipivoxil (AD), a nucleoside reverse transcriptase inhibitor effective against hepatitis B virus (HBV). The prepared proliposomal formulae were characterized for entrapment efficiency (E.E.%), vesicle size and in vitro drug release after reconstitution to conventional liposomes. The optimized formula (F9) with a maximum desirability value of 0.858 was selected having E.E.% of 71 ± 3.3% with an average vesicle size of 164.6 ± 5 nm. Moreover, the crystallization of AD within the optimized formula investigated via powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed the presence of the drug in an amorphous state within the lipid vesicles with enhanced stability over a storage period of 12 months. Thioacetamide-induced liver damage in rats evidenced by elevated liver enzymes was significantly improved after treatment with the optimum formula. Pharmacokinetic and biodistribution studies of formula F9 showed a higher accumulation of AD in the liver with enhanced bioavailability compared to AD suspension which highlights its potential advantage for an effective treatment of chronic HBV. Hence, proliposomal drug delivery is considered as a better choice for the oral delivery of AD.