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

BACKGROUND/AIMS

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

In silico analysis and experimental validation of azelastine hydrochloride (N4) targeting sodium taurocholate co-transporting polypeptide (NTCP) in HBV therapy

OBJECTIVES

The aim of this study was to explore sodium taurocholate co-transporting polypeptide (NTCP) exerting its function with hepatitis B virus (HBV) and its targeted candidate compounds, in HBV therapy.

MATERIALS AND METHODS

Identification of NTCP as a novel HBV target for screening candidate small molecules, was used by phylogenetic analysis, network construction, molecular modelling, molecular docking and molecular dynamics (MD) simulation. In vitro virological examination, q-PCR, western blotting and cytotoxicity studies were used for validating efficacy of the candidate compound.

RESULTS

We used the phylogenetic analysis of NTCP and constructed its protein-protein network. Also, we screened compounds from Drugbank and ZINC, among which five were validated for their authentication in HepG 2.2.15 cells. Then, we selected compound N4 (azelastine hydrochloride) as the most potent of them. This showed good inhibitory activity against HBsAg (IC50 = 7.5 μm) and HBeAg (IC50 = 3.7 μm), as well as high SI value (SI = 4.68). Further MD simulation results supported good interaction between compound N4 and NTCP.

CONCLUSIONS

In silico analysis and experimental validation together demonstrated that compound N4 can target NTCP in HepG2.2.15 cells, which may shed light on exploring it as a potential anti-HBV drug.

Impact of lamivudine-resistance mutations on entecavir treatment outcome in hepatitis B

BACKGROUND AND OBJECTIVE

Entecavir (ETV) is a potent inhibitor of viral replication in nucleos(t)ide analog (NA)-naive chronic hepatitis B patients with a very low rate of resistance (≤1.2%) over 5 years. The aim of this study was to assess the efficacy of ETV treatment in routine clinical practice and to investigate whether persistence of residual viral replication was the result of the emergence and selection of drug-resistant mutants.

PATIENTS AND METHODS

Chronic hepatitis B patients treated with ETV were consecutively recruited from the Department of Hepatology, Hospices Civils de Lyon, France, and were monitored regularly within their routine clinical follow-up. Virological, biochemical, clinical, and tolerance findings were assessed prospectively.

RESULTS

A total of 79 patients were studied, of whom 58% received ETV as a first-line therapy. During ETV therapy (median follow-up 42 months), hepatitis B virus (HBV) DNA became undetectable in 95% of patients. Time to HBV DNA undetectability was significantly shorter in patients with an HBV DNA level less than 4 log10 IU/ml at baseline and in HBeAg-negative patients. Moreover, time to undetectability was significantly shorter in patients with no or only one lamivudine-resistance (LAMr) mutation than in patients with two or more LAMr mutations (P=0.050). No patient had renal-function impairment during ETV therapy.

CONCLUSION

In routine clinical practice, ETV is effective in both NA-naive and NA-experienced patients, except in patients with HBV strains harboring at least two LAMr mutations. The analysis of viral genome sequence at the time of treatment adaptation could prove useful to personalize antiviral therapy in patients failing a previous line of treatment.

Novel single-step multiplex real-time polymerase chain reaction assay for simultaneous quantification of hepatitis virus A, B, C, and E in serum

BACKGROUND AND AIM

Viral hepatitis needs an earliest diagnosis for its proper and timely treatment. Although serodiagnosis of viral hepatitis is in regular practice, however, it has certain limitations and points to alternate procedures of diagnosis. Present study was designed to develop a single-step multiplex real-time polymerase chain reaction (PCR) assay for detection of hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis E virus (HEV) related nucleic acids in sera from infected patients.

METHODS

The PCR was standardized to detect HAV, HBV, HCV and HEV in serum using variables including annealing temperature, extension temperature, MgCl2 , and primer concentrations. The conserved regions of all viral genomes were used as targets for amplification.

RESULTS

This novel assay was found to be a fast, sensitive, specific, and reproducible system for detection of HAV, HBV, HCV, and HEV in serum. The detection limit for different viral genomes at 100% level was found to be 280 copies/mL for HAV, 290 copies/mL for HBV, 30 copies/mL for HCV, and 300 copies/mL for HEV in a single-tube assay system.

CONCLUSION

Present multiplex real-time PCR is the first report on single-step nucleic acid detection of HAV, HBV, HCV, and HEV in sera samples. It is an alternate diagnostic assay for common use in laboratories analyzing viral hepatitis cases.

Efficacy and tolerance of a combination of tenofovir disoproxil fumarate plus emtricitabine in patients with chronic hepatitis B: a European multicenter study

BACKGROUND AND AIMS

The combination of tenofovir disoproxil fumarate (TDF) plus emtricitabine (FTC) is used extensively to treat HIV infection and also has potent activity against hepatitis B virus (HBV) infection. The aim of this study was to assess the efficacy and tolerance of TDF + FTC in patients with chronic hepatitis B (CHB).

METHODS

Seventy eight consecutive CHB patients from five European centers were included. All started a TDF + FTC combination between October 2005 and March 2010. Virological, biochemical, and clinical data were recorded during follow-up. Tolerance was also monitored. Patients were classified into either treatment simplification (TS), where efficacy of the previous treatment was obtained at TDF + FTC initiation, and treatment intensification (TI), where the previous line of therapy had failed.

RESULTS

TDF + FTC was given as a TI to 54 patients (69%) and as a TS to 24 (31%). Among patients with TI, 83% were males. The median baseline HBV-DNA was 4.4 log10 IU/mL, and median alanine-transaminase (ALT) was 1.10 × ULN. Sixty percent were HBeAg positive, 47% had significant fibrosis (≥ F3 Metavir equivalent), and 29% had confirmed cirrhosis. Median treatment duration was 76 weeks (interquartile range 60-116). Kaplan-Meier analysis showed that, 48 weeks after TI, the probability of being HBV-DNA becoming undetectable was 76%, and reached 94% at week 96. No viral breakthrough occurred. Patients with TS (87% males, median baseline HBV-DNA 1.1 log10 IU/mL, median ALT 0.79 × ULN, 33% HBeAg positive, 61% with significant fibrosis) were treated for a median duration of 76 weeks. In this subgroup, all patients but one remained HBV-DNA undetectable and no ALT flare-up occurred during follow-up. Creatinine levels did not show kidney-function deterioration in either group of patients.

CONCLUSIONS

After a median follow-up of > 76 weeks, the TDF + FTC combination showed encouraging antiviral efficacy and a good safety profile in all patients with CHB. TDF + FTC may represent an interesting clinical option to simplify therapy and increase the barrier to resistance, which should be assessed in the long term.

Prospects for personalizing antiviral therapy for hepatitis C virus with pharmacogenetics

Chronic hepatitis C virus (HCV) infection is a major cause of liver disease worldwide. HCV infection is currently treated with IFNα plus ribavirin for 24 to 48 weeks. This demanding therapy fails in up to 50% of patients, so the use of pharmacogenetic biomarkers to predict the outcome of treatment would reduce futile treatment of non-responders and help identify patients in whom therapy would be justified. Both IFNα and ribavirin primarily act by modulating the immune system of the patient, and HCV uses multiple mechanisms to counteract the antiviral effects stimulated by therapy. Therefore, response to therapy is influenced by variations in human genes governing the immune system and by differences in HCV genes that blunt antiviral immune responses. This article summarizes recent advances in understanding how host and viral genetic variation affect outcome of therapy. The most notable human associations are polymorphisms within the IL28B gene, but variations in human leukocyte antigen and cytokine genes have also been associated with treatment outcome. The most prominent viral genetic association with outcome of therapy is that HCV genotype 1 is much less sensitive to treatment than genotypes 2 and 3, but genetic differences below the genotype level also influence outcome of therapy, presumably by modulating the ability of viral genes to blunt antiviral immune responses. Pharmacogenetic prediction of the outcome of IFN-based therapy for HCV will require integrating the efficacies of the immunosuppressive mechanisms of a viral isolate, and then interpreting the viral resistance potential in context of the genetic profile of the patient at loci associated with outcome of therapy. Direct-acting inhibitors of HCV that will be used in combination with IFNα are nearing approval, so genetic prediction for anti-HCV therapy will soon need to incorporate viral genetic markers of viral resistance to the new drugs.

Hepatitis B virus: from diagnosis to treatment

During the next few decades, vaccination against hepatitis B virus (HBV) will dramatically change the epidemiological profile of this worldwide infection especially when Heath Policies encourage including HBV vaccination program for the newborns. However, it is still estimated that more than 2000millions living people have met HBV. Symptomatic hepatitis with jaundice is less frequent than asymptomatic infection; however, as much as 350millions of individuals remain chronically infected by HBV. In these cases, the need for efficient antiviral therapy remains clear when a viral replication is observed to control the risk of progression and the need for liver transplantation, which represents the only end-stage treatment. Indeed, patients having chronic hepatitis B (CHB) can now be successfully treated using nucleos(t)ide analogs (NA) or pegylated interferon (PEG-IFN). Therefore, beside vaccination, prevention of the progression of the disease to cirrhosis and liver decompensation, leading to end-stage liver disease and/or to hepatocellular carcinoma, by inhibiting viral replication seems to represent the best approach to improve survival. At last but not least, co-morbidities and other viral infections, leading also to chronic liver cirrhosis or liver inflammation such as the specific satellite delta virus (HDV), human immunodeficency virus (HIV) and/or hepatitis C (HCV) virus, are able to accelerate the progression and have to be taken in account. Interestingly, in treated infection, the dogma of the irreversibility of the liver fibrosis, when the cirrhosis is constituted, is tumbling down. In this review, we will focus on the clinical, virological and therapeutic aspects of hepatitis B infection in order to expose the proposals to follow-up and treat HBV-infected patients and the prevention of drug-resistant HBV mutants that frequently arise, leading to treatment failure and progression to liver disease.

End points of therapy in chronic hepatitis B

This review assesses the relevance of the clinical, histological, biochemical and virological end points in the course and outcome of chronic hepatitis B. The pathway and the impact of the variation in these end points are presented, as well as their definitions. The treatment goals are discussed in terms of quality of life and survival. Prevention of the progression of the disease to cirrhosis, decompensated cirrhosis, end-stage liver disease and hepatocellular carcinoma seems to be the best approach to improve survival. As these criteria are long-term end points, easier to use end points assessed in clinical trials as efficacy objectives were also analyzed to determine whether they can be used as accurate surrogate criteria. Results of therapy were then analyzed according to the approved end points and in terms of management of chronic hepatitis B. Finally, an attempt to define new clinical end points is discussed in view of the development of more potent antiviral strategies.