Emergence and takeover of YMDD motif mutant hepatitis B virus during long-term lamivudine therapy and re-takeover by wild type after cessation of therapy

Tenofovir disoproxil fumarate therapy to prevent hepatitis B virus vertical transmission-A review of maternal and infant outcomes

Hepatitis B virus (HBV) is a global health problem. Vertical transmission of HBV from HBV surface antigen (HBsAg)-positive mothers to their infants is the most common cause of HBV infection worldwide. The use of passive-active immunoprophylaxis is >90% effective in reducing the risk of vertical transmission, but immunoprophylaxis failure can occur in infants born to mothers with high viraemia. Thus, it is recommended that pregnant women with HBV-DNA level >200 000 IU/ml receive nucleos(t)ide analogue (NA) treatment [i.e. tenofovir disoproxil fumarate (TDF), lamivudine or telbivudine] during third trimester to prevent infant immunoprophylaxis failure. TDF is recommended as the first-line therapy based on available data on efficacy, safety and resistance profile. However, maternal immunological reconstitution following parturition can increase immune-mediated flares to viral antigens that is potentially exacerbated following TDF withdrawal. In this article, we review available data on the efficacy and safety of TDF administration to prevent HBV mother-to-child transmission. We also discuss changes in maternal viral markers [i.e. HBV-DNA, HBV e antigen and HBsAg] and alanine aminotransferase during follow-up post-partum in mothers received NA to prevent HBV vertical transmission.

The association between serum cytokine and chemokine levels and antiviral response by entecavir treatment in chronic hepatitis B patients

BACKGROUND

Although nucleoside/nucleotide analogue therapy is thought to suppress chronic hepatitis B (CHB) via regulation of inflammatory cytokines/chemokines, the mechanism is still unclear. In this study, serum cytokine/chemokine levels were measured in CHB patients treated with entecavir, and the association with antiviral response was analysed.

METHODS

A total of 78 Japanese patients with CHB were enrolled, and serum cytokine/chemokine levels were measured at baseline and at 12, 24 and 48 weeks of entecavir treatment using the MULTIPLEX kit.

RESULTS

Antiviral response to entecavir treatment was significantly associated with hepatitis B surface antigen (HBsAg) titre and serum interferon-gamma-inducible protein 10 (IP-10) level (12w; P=0.0002; OR=0.020 [95% CI 0.002, 0.156], P=0.003; OR=0.042 [95% CI 0.005, 0.336], respectively). HBe-positive patients whose serum macrophage-derived chemokine (MDC) level was lower (<582.83 pg/ml) and IP-10 level was higher (≥1,323.13 pg/ml) achieved hepatitis B e antigen (HBeAg) loss earlier than those who remained HBeAg-positive (P=0.044). HBsAg reduction by entecavir treatment was significantly associated with higher initial tumour necrosis factor-alpha (TNF-α) level (≥15.20 pg/ml) and higher alanine aminotransferase level (≥73 IU/l; P=0.009; OR=18.460 [95% CI 2.044, 166.709], P=0.022; OR=7.709 [95% CI 1.341, 44.327], respectively).

CONCLUSIONS

Results of the present study indicate that changes in cytokine/chemokine levels following entecavir therapy are associated with response to antiviral therapy in CHB patients. Monitoring of serum cytokine/chemokine levels could be useful for predicting reduction of HBV DNA and HBsAg and HBe seroconversion.

Intertwined: SAMHD1 cellular functions, restriction, and viral evasion strategies

SAMHD1 was initially described for its ability to efficiently restrict HIV-1 replication in myeloid cells and resting CD4⁺ T cells. However, a growing body of evidence suggests that SAMHD1-mediated restriction is by far not limited to lentiviruses, but seems to be a general concept that applies to most retroviruses and at least a number of DNA viruses. SAMHD1 anti-viral activity was long believed to be solely due to its ability to deplete cellular dNTPs by enzymatic degradation. However, since its discovery, several new functions have been attributed to SAMHD1. It has been demonstrated to bind nucleic acids, to modulate innate immunity, as well as to participate in the DNA damage response and resolution of stalled replication forks. Consequently, it is likely that SAMHD1-mediated anti-viral activity is not or not exclusively mediated through its dNTPase activity. Therefore, in this review, we summarize current knowledge on SAMHD1 cellular functions and systematically discuss how these functions could contribute to the restriction of a broad range of viruses besides retroviruses: herpesviruses, poxviruses and hepatitis B virus. Furthermore, we aim to highlight different ways how viruses counteract SAMHD1-mediated restriction to bypass the SAMHD1-mediated block to viral infection.

Endoplasmic reticulum-mediated induction of interleukin-8 occurs by hepatitis B virus infection and contributes to suppression of interferon responsiveness in human hepatocytes

The events in the immune response to hepatitis B virus (HBV) remain unclear. We analyzed the direct influence of HBV on gene expression in human hepatocytes under immunodeficient conditions using a human hepatocyte chimeric mouse model. HBV-infected or non-infected chimeric mouse livers were collected, and gene expression profiles were compared. Since IL-8 was the most significantly up-regulated gene at 8 weeks after HBV infection, we focused on IL-8 and found that HBx and the large HBs (L-HBs) protein induce transcription of IL-8 via endoplasmic reticulum stress. This stress induces IL-8 transcription via NFAT activation and contributes to suppression of interferon responsiveness in HBV-infected human hepatocytes. In the present study, we identified a novel regulatory mechanism in which the L-HBs protein activates IL-8 via endoplasmic reticulum stress, suggesting a key role for IL-8 in the immune response to HBV and a potential new target for antiviral treatments of HBV infection.

Efficacy and safety of tenofovir in preventing mother-to-infant transmission of hepatitis B virus: a meta-analysis based on 6 studies from China and 3 studies from other countries

BACKGROUND

The vertical transmission of HBV from mothers to their infants at birth or in early infancy has a significant role in the endemicity of HBV infection. Tenofovir is one of the most potent anti-HBV agents with a high genetic barrier to resistance. The study is to evaluate the efficacy of tenofovir in preventing perinatal HBV transmission, as well as monitoring safety for mothers and infants.

METHODS

PubMed, Embase, Web of Science, and CNKI (National Knowledge Infrastructure, China) database were systematically reviewed for studies that compared the efficacy and safety of tenofovir with other treatments. Pooled estimates were expressed with weight mean difference (WMD) with 95% confidence intervals (95% CIs) and risk ratio (RR) with 95% CIs.

RESULTS

Nine studies involving 1046 pregnant patients met the inclusion criteria and were included in this meta-analysis. Compared with other treatments, tenofovir significantly reduced maternal HBV DNA levels (WMD = 2.33 log10 IU/mL, 95% CI: 1.01, 3.64; P < 0.001), infant HBsAg positivity rate (RR = 0.25, 95% CI: 0.16, 0.38; P < 0.001), infant HBeAg positivity rate (RR = 0.26, 95% CI: 0.14, 0.48; P < 0.001), infant HBV DNA positivity rate (RR = 0.15, 95% CI: 0.07, 0.31; P < 0.001), and immunoprophylaxis failure rate (RR = 0.31, 95% CI: 0.13, 0.73; P = 0.008). Moreover, maternal and infant safety profiles, including ALT, CK, and Cr were comparable between tenofovir and other treatment groups.

CONCLUSION

Based on the current evidence, our study suggested that tenofovir significantly reduced the rate of vertical transmission of HBV, as well as the HBV DNA levels in HBV-infected mothers. Moreover, tenofovir was safe and tolerable for both mothers and their infants.

Antiviral therapy for hepatitis B virus during second pregnancies

Mother-to-child transmission of the hepatitis B virus (HBV) is a major concern for infected mothers, especially after their first child has become an HBV carrier despite immunoprophylaxis. Eight mothers whose first child had become an HBV carrier despite immunoprophylaxis were referred for antiviral therapy during the subsequent pregnancy. All pregnant women were seropositive for both the hepatitis B surface antigen and hepatitis B e antigen. In the treatment group (three receiving lamivudine and two receiving tenofovir), mother-to-child transmission of the HBV was successfully prevented in all infants (5/5). On the other hand, two of three infants became HBV carriers in the untreated group. There were no significant adverse effects in either mothers or infants. Antiviral therapy using lamivudine and tenofovir during the second pregnancy successfully prevented mother-to-child transmission of the HBV for high-risk mothers.

Comparative evaluation of long-term monotherapies & combination therapies in patients with chronic hepatitis B: A pilot study

Background & objectives:

Reduction of viraemia in patients with chronic hepatitis B virus (HBV) infection using nucleoside/nucleotide analogues reduces fatal liver disease-related events, but development of resistance in virus presents serious clinical challenge. Therefore, comparative evaluation of prolonged antiviral monotherapy and combination therapies was prospectively studied to assess their influence on viral suppression, rapidity of response, development of drug resistance and surfacing mutants in chronic liver disease (CLD) patients.

Methods:

A total of 158 (62eAg-ve) chronic hepatitis B patients were prospectively studied for 24 months. Final analysis was performed on patients treated with lamivudine (LAM, n = 28), adefovirdipivoxil (ADV, n = 24), tenofovir disoproxil fumarate (TDF, n = 26), entecavir (ETV, n = 25), LAM + ADV (n = 28) and LAM + TDF (n = 27). Quantitative hepatitis B virus DNA was detected using real-time polymerase chain reaction. Multiple comparisons among drugs and genotypic mutations were analyzed.

Results:

Progressive biochemical and virological response were noted with all the regimens at 24 months except LAM and ADV which were associated with viral breakthrough (VBT) in 46.4 and 25 per cent, respectively. Mutations: rtM204V (39.3%), M204V+L180M (10.7%) while rtA181V (8.1%) and rtN236T (8.3%) were observed with LAM and ADV regimen, respectively. LAM + ADV combination therapy revealed VBT in seven per cent of the cases without mutations whereas TDF, ETV and LAM + TDF therapies neither showed VBT nor mutations.

Interpretation & conclusions:

LAM was the least potent drug among all therapeutic options followed by ADV. TDF and ETV were genetically stable antivirals with a strong efficacy. Among newer combination therapies, LAM + TDF revealed more efficacy in virological remission and acted as a profound genetic barrier on long term. Hence, newer generation molecules (TDF, ETV) and effective combination therapy should be a certain choice.

Hepatitis B Virus (HBV) Load Response to 2 Antiviral Regimens, Tenofovir/Lamivudine and Lamivudine, in HIV/ HBV-Coinfected Pregnant Women in Guangxi, China: The Tenofovir in Pregnancy (TiP) Study

BACKGROUND

 There is limited information on antiviral therapy for hepatitis B virus (HBV) infection among pregnant women coinfected with human immunodeficiency virus (HIV) and HBV.

METHODS

 A phase 2 randomized, controlled trial of a regimen containing tenofovir (TDF)/lamivudine (3TC) and a regimen containing 3TC in HIV/HBV-coinfected pregnant women in China. The HBV virological response was compared in study arms.

RESULTS

 The median decline in the HBV DNA level was 2.60 log10 copies/mL in the TDF/3TC arm and 2.24 log10 copies/mL in the 3TC arm (P = .41). All women achieved HBV DNA levels of <6 log10 copies/mL at delivery.

CONCLUSIONS

 Initiation of either regimen led to achievement of HBV DNA levels below the threshold associated with perinatal HBV transmission.

CLINICAL TRIALS REGISTRATION

 NCT01125696.

Current molecular methods for the detection of hepatitis B virus quasispecies

Chronic HBV infection affects more than 240 million people worldwide and is associated with a broad range of clinical manifestations including liver cirrhosis, liver failure and hepatocellular carcinoma. Because of the lack of an efficient cure for chronic hepatitis B, the main goal of antiviral therapy is the prevention of liver disease progression coupled with prolonged survival of patients. Because HBV viral load has been shown to be a crucial determinant of the progression of liver damage, these goals can be achieved as long as HBV replication can be suppressed. Unfortunately, long-term therapy with the low-to-moderate genetic barrier drugs, which are still recommended in a majority of developing countries, are strongly associated with HBV resistance development and treatment failure. In such cases, the precise and accurate determination of drug-resistant variants in an individual patient before treatment is important for a proper choice of first-line potent therapy. Nowadays, a number of techniques are available to study HBV quasispecies evolution. This review describes the advantages and limitations of various assays detecting drug-resistant HBV variants. Copyright © 2016 John Wiley & Sons, Ltd.

Dynamic Characteristics of Serum Hepatitis B Surface Antigen in Chinese Chronic Hepatitis B Patients Receiving 7 Years of Entecavir Therapy

BACKGROUND

The ultimate goal of hepatitis B treatment is hepatitis B surface antigen (HBsAg) seroclearance. Several factors have been suggested to be associated with the rate of HBsAg reduction in antiviral-naive or lamivudine therapy cohorts. However, there are few studies evaluating the factors during long-term entecavir (ETV) therapy. In the present study, we aimed to evaluate the factors to predict the outcome of ETV therapy for 7 years.

METHODS

A total of 47 chronic hepatitis B (CHB) patients treated with ETV monotherapy were included in this study. Liver biochemistry, hepatitis B virus (HBV) serological markers, serum HBV DNA, and HBsAg titers were tested at baseline, 3 months, 6 months, and yearly from 1 to 7. The associations between factors and HBsAg reduction were assessed using multivariate tests with repeated measure analysis of variance.

RESULTS

At baseline, serum HBsAg levels showed a positive correlation with baseline HBV DNA levels (r = 0.625, P < 0.001). The mean HBsAg titers after ETV treatment were significantly lower than the baseline titers (P ranges from 0.025 to 0.000,000,6). The HBsAg reduction rate during the 1st year was greater compared to after 1 year of treatment (P < 0.05). Multivariate test showed that hepatitis B e antigen (HBeAg) seroclearance and/or HBsAg reduction ≥0.5 log10 IU/ml at 6 months had a high negative predictive value (96.77%) for HBsAg seroclearance (P = 0.002, P = 0.012, respectively).

CONCLUSIONS

The HBsAg reduction rate during the 1st year was greater than that after 1 year of treatment. Further, HBeAg status and HBsAg levels at month 6 are the optimal factors for the early prediction of HBsAg seroclearance after long-term ETV therapy in CHB patients.

Evolution of entecavir-resistant hepatitis B virus during entecavir and adefovir dipivoxil combination therapy

The emergence of entecavir (ETV) resistance is rare, particularly in a longitudinal study. The aim of the present study was to characterize the evolution of ETV-resistant variants during antiviral therapy using entecavir monotherapy followed by ETV-adefovir dipivoxil (ADV) combination therapy. The study included a prospective cohort of 53 consecutive chronic hepatitis B (CHB) patients. During the 60-month period of ETV therapy, 2 patients exhibited ETV resistance and their medical records were comprehensively reviewed. A total of 25 consecutive serum samples were regularly collected from the 2 patients. All the samples were used to characterize the evolution of the polymerase gene mutations using pyrosequencing. The linkage of the variants was analyzed from 87 reverse transcriptase sequences of 3 selective samples using clone sequencing. The 2 patients presented with viral breakthrough during ETV monotherapy. In patient A, the rtL180M, rtS202G and rtM204V mutant variants were detected using pyrosequencing prior to virological breakthrough. Although the viral load declined following the administration of ADV, the ETV-resistant variants were persistently dominant in the viral populations. In patient B, the rtL180M, rtM204I and rtM204V mutants were present in ~70, 30 and 10% of the viral populations, respectively, at the time of study entry. In addition, rtT184F was present in ~20% of the viral population during virological breakthrough, at month 24. The rtL180M, rtT184F and rtM204V were predominant during the combination treatment. Clonal analysis further revealed that the rtS202G or rtT184F was in all cases co-localized with rtL180M and rtM204V in any single virus isolate clone. The results of the present study indicate that the addition of ADV therapy with ETV for treating ETV-resistant mutation may not inhibit the replication of ETV-resistant variants that developed previously in lamivudine-treated CHB patients.

Clinical course of 161 untreated and tenofovir-treated chronic hepatitis B pregnant patients in a low hepatitis B virus endemic region

Hepatitis B immunoprophylaxis failure is linked to high maternal viraemia. There is limited North American data on hepatitis B outcomes in pregnancy. Pregnant hepatitis B carriers were enrolled January 2011-December 2014 and offered tenofovir in the 3rd trimester if hepatitis B virus (HBV)-DNA was >7-log IU/mL. Outcomes were determined in treated vs untreated patients. In total, 161 women with 169 pregnancies (one twin, 170 infants; median age 32 years), 18% (29/161) HBeAg+ and median HBV-DNA 2.51 log IU/mL (IQR 1.66-3.65; range 0.8-8.1) were studied. 14.3% (23/161) received tenofovir due to high viral load (16/23, median 74 days, IQR 59-110) or due to liver disease (7/23). In 10/16 treated due to high viraemia, with confirmed adherence, follow-up HBV-DNA showed a 5.49 log decline (P = 0.003). In treatment naïve mothers, median alanine aminotransferase (ALT) increased from 17 IU/L (IQR 12-24) to 29 (IQR 18-36) post-partum (P = 1.5e-7). In seven highly viraemic mothers who declined therapy (HBV-DNA >8-log IU/mL); median ALT increased ~3X from baseline (P < 0.01). 26% (44/169) had Caesarean section with no difference in treated vs untreated subjects. No tenofovir-treated mothers had renal dysfunction. Data were available on 167/170 infants; in 50.8% (85/167) who completed immunoprophylaxis, 98.8% (84/85, including 12 exposed to tenofovir in utero) were HBV immune. One infant born to an HBeAg+ mother with HBV-DNA >8-log IU/mL failed immunoprophylaxis. In this prospective Canadian cohort study, most untreated mothers experienced mild HBV flares. Tenofovir in pregnancy is well tolerated and reduces viral load prior to parturition.

A novel method for nucleos(t)ide analogues susceptibility assay of hepatitis B virus by viral polymerase transcomplementation

Nucleos(t)ide analogues (NUCs) susceptibility assay is important for the study of hepatitis B virus (HBV) drug resistance. The purpose of susceptibility assay is to test the sensitivity of a specific HBV variant to NUCs in vitro, by which assesses if and to what extent the mutant virus is resistant to a specific NUC. Among the existing susceptibility assay methods, stable cell line expressing the specific variant is one of the commonly used assessment systems based on its high repeatability. However, establishment of stable cell lines expressing individual variant is laborious and time-consuming. In the present study, we developed a novel strategy for rapidly establishing HBV replicating stable cell lines. We first established an acceptor cell line stably transfected with a polymerase-null HBV 1.1mer genome DNA, then lentiviruses expressing different mutant HBV polymerases were transduced into the acceptor cell line respectively. Stable cell lines replicating HBV DNA with the trans-complemented HBV polymerases were established by antibiotics selection. Lamivudine and entecavir susceptibility data from these polymerase-complementing cell lines were validated by comparing with other assays. Taken together, this transcomplementation strategy for establishment of stable cell lines replicating HBV DNA with clinically isolated HBV polymerase provides a new tool for NUC susceptibility assay of HBV.

Lamivudine Resistance and Precore Variants in Iranian Patients With Chronic Hepatitis B: Correlation With Virological and Clinical Features

BACKGROUND

Long-term lamivudine therapy, despite its initial effectiveness against hepatitis B virus (HBV), is associated with the emergence of drug resistance mutations in polymerase protein.

OBJECTIVES

The aim of the present study was to determine the prevalence of precore and lamivudine drug resistance mutations in lamivudine treated patients with chronic B hepatitis.

PATIENTS AND METHODS

Sequential sera were obtained from 88 chronic HBV carriers who received lamivudine for more than 24 months. Polymerase and precore regions were directly sequenced for these groups: I (before treatment), II, and III (12 and 24 months after treatment, respectively).

RESULTS

All patients (100%) were contained genotype D, subtype ayw2. One (1.1%), 12 (13.6%), and 22 (25%) members of groups I, II, and III had the replacement of either isoleucine or valine instead of methionine in tyrosine-methionine-aspartate-aspartate (YMDD) motif, respectively. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an increasing trend between sequential samples (P < 0.001). In group I, 31 (35.2%); II, 36 (41.0%) and III, 41 (46.6%) members had the precore stop codon mutations. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an ascending trend between sequential samples. Indeed, frequency of precore stop codon was significantly increased with the passage of time (P < 0.001).

CONCLUSIONS

Presence of drug resistance mutations among the patients was significant. Precore mutations were common amongst Iranian HBV chronic carriers under lamivudine therapy and these mutations were accompanied by clinical relapse.

Adefovir nephrotoxicity in a renal allograft recipient

Adefovir dipivoxil, an oral prodrug of adefovir, is used in the treatment of lamivudine-resistant hepatitis B virus (HBV) infection. Nephrotoxicity manifesting as proximal renal tubular dysfunction and acute tubular necrosis (ATN) were commonly reported in the past, when higher doses were used for the treatment of human immunodeficiency virus infection. However, nephrotoxicity is rare at lower doses that are currently recommended for the treatment of HBV infection. A 31-year-old female was detected to be hepatitis B surface antigen positive months after a kidney transplant. The patient was initiated on lamivudine, but developed resistance after 1 year of treatment, at which time low-dose adefovir was added. The patient developed renal allograft dysfunction after 10 months of starting adefovir. Serum creatinine increased from 1.1 mg/dl to 1.9 mg/dl, along with progressively increasing sub-nephrotic proteinuria. Renal allograft biopsy revealed features of ATN. After discontinuation of adefovir, proteinuria resolved and renal dysfunction improved slowly over the next 2 years. Adefovir-induced nephrotoxicity, although uncommon at lower doses, needs to be considered in the differential diagnosis of renal dysfunction and sub-nephrotic proteinuria occurring in patients receiving adefovir for prolonged periods.

The characteristic changes in hepatitis B virus x region for hepatocellular carcinoma: a comprehensive analysis based on global data

OBJECTIVES

Mutations in hepatitis B virus (HBV) X region (HBx) play important roles in hepatocarcinogenesis while the results remain controversial. We sought to clarify potential hepatocellular carcinoma (HCC)-characteristic mutations in HBx from HBV genotype C-infected patients and the distribution of those mutations in different disease phases and genotypes.

METHODS

HBx sequences downloaded from an online global HBV database were screened and then classified into Non-HCC or HCC group by diagnosis information. Patients' data of patient age, gender, country or area, and viral genotype were also extracted. Logistic regression was performed to evaluate the effects of mutations on HCC risk.

RESULTS

1) Full length HBx sequences (HCC: 161; Non-HCC: 954) originated from 1115 human sera across 29 countries/areas were extracted from the downloaded 5956 HBx sequences. Genotype C occupied 40.6% of Non-HCC (387/954) and 89.4% of HCC (144/161). 2) Sixteen nucleotide positions showed significantly different distributions between genotype C HCC and Non-HCC groups. 3) Logistic regression showed that mutations A1383C (OR: 2.32, 95% CI: 1.34-4.01), R1479C/T (OR: 1.96, 95% CI: 1.05-3.64; OR: 5.15, 95% CI: 2.53-10.48), C1485T (OR: 2.40, 95% CI: 1.41-4.08), C1631T (OR: 4.09, 95% CI: 1.41-11.85), C1653T (OR: 2.58, 95% CI: 1.59-4.19), G1719T (OR: 2.11, 95% CI: 1.19-3.73), and T1800C (OR: 23.59, 95% CI: 2.25-247.65) were independent risk factors for genotype C HBV-related HCC, presenting different trends among individual disease phases. 4) Several genotype C HCC risk mutations pre-existed, even as major types, in early disease phases with other genotypes.

CONCLUSIONS

Mutations associated with HCC risk were mainly located in HBx transactivation domain, viral promoter, protein/miRNA binding sites, and the area for immune epitopes. Furthermore, the signatures of these mutations were unique to disease phases leading to HCC, suggesting molecular counteractions between the virus and host during hepatocarcinogenesis.

Increased replicative fitness can lead to decreased drug sensitivity of hepatitis C virus

Passage of hepatitis C virus (HCV) in human hepatoma cells resulted in populations that displayed partial resistance to alpha interferon (IFN-α), telaprevir, daclatasvir, cyclosporine, and ribavirin, despite no prior exposure to these drugs. Mutant spectrum analyses and kinetics of virus production in the absence and presence of drugs indicate that resistance is not due to the presence of drug resistance mutations in the mutant spectrum of the initial or passaged populations but to increased replicative fitness acquired during passage. Fitness increases did not alter host factors that lead to shutoff of general host cell protein synthesis and preferential translation of HCV RNA. The results imply that viral replicative fitness is a mechanism of multidrug resistance in HCV. Importance: Viral drug resistance is usually attributed to the presence of amino acid substitutions in the protein targeted by the drug. In the present study with HCV, we show that high viral replicative fitness can confer a general drug resistance phenotype to the virus. The results exclude the possibility that genomes with drug resistance mutations are responsible for the observed phenotype. The fact that replicative fitness can be a determinant of multidrug resistance may explain why the virus is less sensitive to drug treatments in prolonged chronic HCV infections that favor increases in replicative fitness.

Kinetics and prediction of HBsAg loss during long-term therapy with nucleos(t)ide analogues of different potency in patients with chronic hepatitis B

BACKGROUND & AIMS

About 350-400 million people are infected with hepatitis B virus (HBV) chronically and 1 million people die of hepatitis B virus (HBV)-related liver diseases. Nucleos(t)ide analogues (NAs) have been used for the treatment against HBV. However, few studies have investigated the long-term effects of different nucleos(t)ide analogues on levels of hepatitis B surface antigen (HBsAg) in patients with chronic hepatitis B (CHB). The aims of this study were to measure the magnitude of HBsAg reduction by long-term monotherapy with adefovir dipivoxil (ADV) and entecavir (ETV), to compare HBsAg reduction between the two drugs of different potency and to predict the expected time needed to achieve HBsAg loss.

METHODS

We retrospectively evaluated the kinetics of HBsAg in 67 patients with CHB who all exhibited persistent viral suppression. These patients were treated with ADV or ETV for at least 6 years. HBV genotype was determined at baseline. Liver biochemistry, HBV serological markers, serum HBV DNA and HBsAg titers were determined at baseline, half year and yearly from year 1 to 6.

RESULTS

Serum HBsAg titers after treatment with ADV or ETV were significantly lower than the baseline titers (P<0.05). HBsAg reduction rate of patients treated with ETV (0.11 log10 IU/mL/ year) was higher than that treated with ADV (0.10 log10 IU/mL/year), and the calculated expected time to HBsAg loss for patients treated with ETV (approximate 24.99 years) was shorter than that with ADV (approximate 30.33 years), but there was no statistically significant difference between two groups (P>0.05).

CONCLUSION

Serum HBsAg titers gradually decreased during long-term treatment with either ADV or ETV. It appears that the potency of ADV on HBsAg reduction is close to that of ETV, as long as patients have achieved persistent viral suppression.

Quasispecies structure, cornerstone of hepatitis B virus infection: mass sequencing approach

Hepatitis B virus (HBV) is a DNA virus with complex replication, and high replication and mutation rates, leading to a heterogeneous viral population. The population is comprised of genomes that are closely related, but not identical; hence, HBV is considered a viral quasispecies. Quasispecies variability may be somewhat limited by the high degree of overlapping between the HBV coding regions, which is especially important in the P and S gene overlapping regions, but is less significant in the X and preCore/Core genes. Despite this restriction, several clinically and pathologically relevant variants have been characterized along the viral genome. Next-generation sequencing (NGS) approaches enable high-throughput analysis of thousands of clonally amplified regions and are powerful tools for characterizing genetic diversity in viral strains. In the present review, we update the information regarding HBV variability and present a summary of the various NGS approaches available for research in this virus. In addition, we provide an analysis of the clinical implications of HBV variants and their study by NGS.

Serum HBV RNA and HBeAg are useful markers for the safe discontinuation of nucleotide analogue treatments in chronic hepatitis B patients

BACKGROUND

Treatment for chronic hepatitis B has improved drastically with the use of nucleot(s)ide analogues (NAs). However, NA therapy typically fails to eliminate Hepatitis B virus (HBV) completely, and it is difficult to discontinue these therapies. We previously demonstrated that NA therapy induced immature viral particles, including HBV RNA in sera of chronic hepatitis B patients. In the study reported here, we analyzed the association between HBV RNA titer and the recurrence rate of hepatitis after discontinuation of NA therapy.

METHODS

The study cohort comprised 36 patients who had discontinued NA therapy. Serum HBV DNA or DNA plus RNA levels were measured by real time PCR and statistical analyses were performed using clinical data and HBV markers.

RESULTS

At 24 weeks after discontinuation of NA therapy, HBV DNA rebound was observed in 19 of the 36 patients (52.8 %), and alanine aminotransferase (ALT) rebound was observed in 12 of 36 patients (33.3 %). Multivariate statistical analysis was used to identify factors predictive of HBV DNA rebound. The HBV DNA + RNA titer following 3 months of treatment was significantly associated with HBV DNA rebound [P = 0.043, odds ratio (OR) 9.474, 95 % confidence interval (CI) 1.069-83.957)]. Absence of hepatitis B e antigen (HBeAg) at the end of treatment was significantly associated with ALT rebound (P = 0.003, OR 13.500, 95 % CI 2.473-73.705). In HBeAg-positive patients, the HBV DNA + RNA titer after 3 months of treatment was marginally associated with ALT rebound (P = 0.050, OR 8.032, 95 % CI 0.997-64.683).

CONCLUSIONS

Monitoring of serum HBV DNA + RNA levels may be a useful method for predicting re-activation of chronic hepatitis B after discontinuation of NA therapy.

Molecular virology of chronic hepatitis B and C: parallels, contrasts and impact on drug development and treatment outcome

Chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are highly prevalent worldwide, causing significant liver disease and thus representing high unmet medical needs. Accordingly, substantial pharmaceutical and clinical research efforts have been made to develop and improve treatments for these viruses. While HBV and HCV are both hepatotropic viruses that can cause similar disease in chronically infected patients, they belong to different viral families. There are substantial differences in the molecular virology of HBV and HCV that have profound implications for therapeutic strategy. In particular, HBV has a long-lived nuclear form of its genome (covalently closed circular DNA) that is able to persist in the face of potent inhibition of viral replication. In contrast, HCV does not have a long-lived genome form and depends on active replication to maintain infection; HCV is therefore much more susceptible to eradication by potent antiviral agents. Additional differences between HBV and HCV with therapeutic implications include the size, structure and heterogeneity of their respective viral genomes. These factors influence the number of targets available for therapeutic intervention, response to therapy among viral genotypes and the emergence of viral resistance. Substantial progress has been made in treating each infection, but unique challenges remain. In this review, key differences in the molecular virology of hepatitis B and C will be presented, highlighting their impact on antiviral therapy (particularly with respect to direct-acting antivirals) and the challenges they present to the cure of each disease.

The HepaRG cell line: a valuable in vitro tool for hepatitis virus infection studies

Hepatitis virus infections, mainly hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, constitute a major problem for public health since they have a worldwide distribution and because they are associated with hepatocellular carcinoma and death. Current anti-HBV vaccines seem to be effective in the majority of people. However, an important issue waiting to be tackled nowadays is how to cure patients with chronic hepatitis B. Moreover, no vaccine is available today for the prevention of HCV infection. Therefore, the use of adequate in vitro infection systems is a prerequisite for the molecular understanding of the infection events of these viruses, which could result in the development of novel powerful therapeutics. In this respect, the HepaRG cell line exhibits a hepatocyte-like morphology and displays drug metabolism capacity similar to that of primary hepatocytes. HepaRG cells have yet been proven to be a useful tool in the study of viral infections, particularly for deciphering the mechanism of HBV entry into hepatocytes.

Pharmacogenomics of Viral Diseases

Viral diseases are leading cause of deaths worldwide as WHO report suggests that hepatitis A virus (HAV) infects more than 80 % of the population of many developing countries. Viral hepatitis B (HBV) affects an estimated 360 million people, whereas hepatitis C affects 123 million people worldwide, and last but not least, at current, India has an HIV/AIDS population of approximately 2.4 million people and more than 30 million in whole world and now it has become a reason for 1.8 million death globally; thus, millions of people still struggle for their lives.

The progress in medical science has made it possible in overcoming the various fatal diseases such as small pox, chicken pox, dengue, etc., but human immunodeficiency viruses, influenza, and hepatitis virus have renewed challenge surprisingly. The obstacles and challenges in therapy include existence of antibiotic resistance strains of common organisms due to overuse of antibiotics, lack of vaccines, adverse drug reaction, and last but not least the susceptibility concerns. Emergence of pharmacogenomics and pharmacogenetics has shown some promises to take challenges. The discovery of human genome project has opened new vistas to understand the behaviors of genetic makeup in development and progression of diseases and treatment in various viral diseases. Current and previous decade have been engaged in making repositories of polymorphisms (SNPs) of various genes including drug-metabolizing enzymes, receptors, inflammatory cells related with immunity, and antigen-presenting cells, along with the prediction of risks. The genetic makeup alone is most likely an adequate way to handle the therapeutic decision-making process for previous regimen failure. With the introduction of new antiviral therapeutic agents, a significant improvement in progression and overall survival has been achieved, but these drugs have shown several adverse responses in some individuals, so the success is not up to the expectations. Research and acquisition of new knowledge of pharmacogenomics may help in overcoming the prevailing burden of viral diseases. So it will definitely help in selecting the most effective therapeutic agents, effective doses, and drug response for the individuals. Thus, it will be able to transform the laboratory research into the clinical bench side and will also help in understanding the pathogenesis of viral diseases with drug action, so the patients will be managed more properly and finally become able to fulfill the promise of the future.

Direct acting antivirals for the treatment of chronic viral hepatitis

The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years have heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus (HBV, HCV, and HDV). The introduction of direct acting antivirals (DDAs) for the treatment of HBV carriers has permitted the long-term use of these compounds for the continuous suppression of viral replication, whilst in the case of HCV in combination with the standard of care [SOC, pegylated interferon (PegIFN), and ribavirin] sustained virological responses (SVRs) have been achieved with increasing frequency. Progress in the case of HDV has been slow and lacking in significant breakthroughs.This paper aims to summarise the current state of play in treatment approaches for chonic viral hepatitis patients and future perspectives.

A case of adefovir-induced membranous nephropathy related to hepatitis B caused by lamivudine-resistant virus after liver transplant due to Byler's disease

We report on how adefovir-induced membranous nephropathy related to hepatitis B was caused by lamivudine-resistant virus after a liver transplant due to Byler's disease. In 1980, a 2-year-old girl was diagnosed with Byler's disease (familial progressive familial intrahepatic cholestasis). In 1994 (at the age of 14 years) she underwent a liver transplant with her father as the donor. In 2003, hematuria and proteinuria appeared and shortly afterwards her renal function rapidly decreased. A renal biopsy showed atypical membranous nephropathy, which suggested the possibility of a secondary renal disease. The patient had suffered from chronic hepatitis type B (HBV). In 2001 she was administered lamivudine which is an antiviral drug; it was around this time that hematuria and proteinuria appeared as well as an increase of the virus titer. We believed the HBV-related membranous nephropathy was the cause of the virus titer and the renal histology. We concluded that the patient's condition had become resistant to lamivudine medication. Therefore, in February 2004 we administered adefovir, a new drug at the time, to treat the HBV. In April 2004, the HB virus titer decreased and the hematuria and proteinuria decreased. The patient's renal function also showed improvement. HBV-associated nephropathy is caused by HBV antigen deposition in the glomeruli. Generally the first choice of treatment is antivirus therapy. There are many reports demonstrating that administration of interferon and lamivudine are effective; however, there are few reports that show adefovir as an effective treatment for HBV-associated nephropathy.

HBsAg variants: diagnostic-escape and diagnostic dilemma

A wide variety of commercial assays is available for the detection of hepatitis B surface antigen (HBsAg). Clearly, the sensitivity of an assay to detect a variant is dependent on the anti-HBs usage. Thus, it is not surprising that there are examples of variants that cannot be detected by all assays. Data from Europe, Asia and Africa about HBsAg variants which are not recognized by either monoclonal or polyclonal antibodies specific for wild-type group 'a' determinant, but positive by DNA polymerase chain reaction (PCR) in chronic patients and from vaccinated children are increasing. This would impose a challenge for public health issues of hepatitis B virus. In this review we tried to summarize the discrepancies between results of HBsAg assays and to explain some rationales for these inconsistencies.

Detection of mixed populations of wild-type and YMDD hepatitis B variants by pyrosequencing in acutely and chronically infected patients

BACKGROUND

Lamivudine (LAM) is associated with the highest known rate of resistance mutations among nucleotide analogs used to treat chronic hepatitis B virus (HBV) infection. Despite this, LAM continues in widespread use, especially in combination therapies. The primary LAM resistance mutation (rtM204V/I) occurs in the YMDD motif of HBV polymerase. The aim of this study was to characterize Brazilian HBV isolates from acute and chronic cases by direct sequencing, and to identify HBV quasispecies in the YMDD motif using a pyrosequencing method capable of detecting single-nucleotide polymorphisms. HBV DNA from serum samples of 20 individuals with acute HBV infection and 44 with chronic infection undergoing antiviral therapies containing LAM were analyzed by direct sequencing and pyrosequencing methods.

RESULTS

Phylogenic analyses of direct-sequenced isolates showed the expected genotypes (A, D and F) for the Brazilian population in both acute and chronic infections. However, within genotype A isolates, subgenotype A2 was more frequently detected in acute cases than in chronic cases (P = 0.012). As expected, none of the individuals with acute hepatitis B had LAM-resistant isolates as a dominant virus population, whether detected by direct sequencing or pyrosequencing. However, pyrosequencing analyses showed that 45% of isolates (9/20) had minor subpopulations (4-17%) of LAM-resistant isolates. Among chronic patients undergoing LAM treatment, YMDD mutants were frequently found as a dominant virus population. In cases where wild-type virus was the dominant population, subpopulations of YMDD variants were usually found, demonstrating the complexity of HBV quasispecies.

CONCLUSIONS

YMDD variants were frequently detected as a minor population in acute HBV infection. The occurrence of pre-existing variants may lead to a high frequency of resistant mutants during antiviral therapy in the chronic phase. In chronic infection, detection of YMDD variants before virological or biochemical breakthrough might contribute to making better therapy choices and thus improving treatment outcome.

Treatment of chronic hepatitis B with nucleos(t)ide analogues

Recently antiviral therapies for chronic hepatitis B using nucleos(t)ide analogues have become standard treatment modalities on the basis of several independent guidelines, starting with those of the American Association for the Study of Liver Diseases (AASLD) and other such organizations and bodies, including the European Association for the Study of the Liver (EASL), the Asian Pacific Association for the Study of the Liver (APASL), and the Japanese Ministry of Health, Labour and Welfare (MHLW)'s research team. The philosophies underlying such treatment strategies are considered basically equivalent. MHLW's guidelines define subjects for medical intervention to be cases measuring alanine aminotransferase (ALT) ≥31 IU/L, with serological hepatitis B virus (HBV) DNA level ≥5 log copies/mL for hepatitis B e antigen (HBeAg)-positive cases, and serological HBV DNA level ≥4 log copies/mL for HBeAg-negative cases. These Japanese guidelines advocate entecavir as the first-line treatment option for nucleos(t)ide-naïve patients, and combination treatment of lamivudine and adefovir as the basis of treatment for patients with lamivudine- and/or entecavir-resistant viruses. Of particular note for patients undergoing lamivudine treatment with persistent HBV DNA level < 2.1 log copies/mL is the recommendation of a switch to entecavir. Early detection of drug-resistant virus is desirable after initiation of nucleos(t)ide analogue treatment, but such a procedure is not uniformly available at all medical institutions. Nevertheless, timely estimation of potential early-stage drug-resistant virus development is crucial for getting a head start on treatment. HBV core-related antigen (HBcrAg) level or HBV DNA level are considered useful markers for the appearance of such drug-resistant viruses.

The influence of YMDD mutation patterns on clinical outcomes in patients with adefovir add-on lamivudine combination treatment

BACKGROUND/AIM

The aim of this study was to assess the patterns of lamivudine (LAM)-resistant mutations and the influence on biochemical and virological responses to adefovir (ADV) add-on LAM combination therapy in patients with LAM-resistant chronic hepatitis B (CHB).

METHODS

Seventy-eight CHB patients with confirmed genotypic resistance to LAM, who initiated ADV add-on LAM combination treatment, were enrolled at our institution between April 2007 and April 2009.

RESULTS

The baseline tyrosine-methionine-aspartate-aspartate (YMDD) mutation patterns were as follows: rtM204I 45 (57.7%); and rtM204V + rtM204I/V 33 (42.3%). The decrease in the mean ± standard deviation (SD) serum log(10) HBV-DNA level did not differ between the patients carrying the rtM204I vs. rtM204IV +rtM204I/V mutations at 3, 6 and 12 months after the initiation of ADV add-on LAM combination treatment. The proportion of patients who achieved ALT normalization (<40 IU/L) 12 months after the initiation of ADV add-on LAM combination treatment were significantly higher in patients with a rtM204I mutation than rtM204V+ rtM204I/V mutations (39 [86.7%] vs. 22 [66.7%], P = 0.05). The proportion of patients in whom the log(10) HBV-DNA decreased <2 log(10) copies/ml, 6 months after the initiation of ADV add-on LAM combination treatment (non-responders), was significantly higher in patients with a rtM204V + rtM204I/V mutations than rtM204I mutation (7 [21.2%] vs. 2 [4.4%], P = 0.032).

CONCLUSION

Biochemical response at 12 months from baseline was better in patients with a rtM204I mutation than rtM204V+ rtM204I/V mutations. In addition, early treatment failure was more common in patients with rtM204V+ rtM204I/V mutations than a rtM204I mutation.

Lamivudine with or without adefovir dipivoxil for postoperative hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a significant cause of death, especially in Asia and sub-Saharan Africa. Removal of the cancer through surgery or other techniques is considered the first-line therapy in early HCC, but relapse of HCC is the main postoperative problem. The main risk factor for HCC is hepatitis B virus (HBV) infection. Lamivudine and adefovir dipivoxil are effective and tolerable for chronic hepatitis B by suppressing the viral load and to reduce fibrosis in the liver.  

OBJECTIVES

To assess the benefits and harms of postoperative administration of lamivudine with or without adefovir dipivoxil in participants with surgically treated HCC and chronic HBV infection or HBV carrier state.

SEARCH METHODS

A systematic search was performed in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded (SCI Exp) in October 2011. Further trials have been sought through scanning reference lists of relevant articles.

SELECTION CRITERIA

Randomised clinical trials comparing the administration of lamivudine with and without adefovir dipivoxil for participants with ablation treated HCC (surgical or through other techniques) and chronic HBV infection or HBV carrier state, regardless of publication status, language, blinding, and publication status, were to be included in this review. We planned to extract data on harms from quasi-randomised studies or cohort studies when retrieved with the search results.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, and extracted and analysed the data. The type and number of adverse events were reported descriptively.

MAIN RESULTS

No randomised trials could be included into this systematic review. Thus, we were unable to follow our pre-published protocol and perform meta-analyses.Through our searches for randomised clinical trials, four cohort trials with 230 participants were retrieved. We read them in order to find data on harm, ie, adverse events. Breakthrough hepatitis was a serious adverse event attributable to lamivudine. No other adverse events seemed to be caused by the administration of lamivudine or adefovir dipivoxil were reported in the four cohort studies.

AUTHORS' CONCLUSIONS

No evidence from randomised trials on the beneficial or harmful effects of lamivudine with or without adefovir dipivoxil for postoperative HCC was found. Randomised clinical trials with large number of participants and long follow-up period should be carried out to direct clinical practice.

Identification of hepatitis B virus rtS117F substitution as a compensatory mutation for rtM204I during lamivudine therapy

OBJECTIVES

The replication defect of hepatitis B virus (HBV) lamivudine-resistant mutants can be restored by the development of compensatory mutations. Such mutations have long been recognized for the rtM204V mutant, while little is known about any compensatory mutation specific to the rtM204I mutant. The aim of this study was to search for previously unrecognized compensatory mutations following development of lamivudine-resistant mutants.

METHODS

Of 83 lamivudine-resistant patients, 49 and 34 patients harboured the rtM204I and rtM204V mutations, respectively. Serial serum samples obtained during the therapeutic course were submitted to sequence analysis. Site-directed mutagenesis experiments were performed to examine the functions of the identified associated mutations.

RESULTS

Of the 49 patients carrying the rtM204I mutation, 5 subsequently developed an rtS117F substitution during the follow-up, whereas 4 harboured an rtN124D substitution prior to the development of the rtM204I mutation. Emergence of the rtS117F mutation was associated with an increase in hepatitis activity, whereas prior existence of the rtN124D mutation was associated with decompensated liver function upon development of the rtM204I mutation. Site-directed mutagenesis experiments showed that the rtS117F mutation by itself did not confer lamivudine resistance but it compensated for replication deficiency of the rtM204I mutant in HepG2 and Mahlavu cells. Additionally, virion and hepatitis B surface antigen secretion of the rtS117F mutant was significantly impaired.

CONCLUSIONS

The rtS117F substitution served as a compensatory mutation for rtM204I. Emergence of the rtS117F mutation in lamivudine-resistant patients carrying rtM204I was associated with increased hepatitis activities. Prior existence of the rtN124D substitution was associated with liver decompensation upon development of the rtM204I mutation.

Hepatitis B virus related membranous glomerulonephritis and proteinuria treated with lamivudine and tenofovir

Membranous glomerulonephritis is the most common histological renal lesion associated with hepatitis B virus (HBV) infection. The authors describe here a case of a patient presenting with the nephrotic syndrome and HBV infection but without progressive liver disease. The use of lamivudine and tenofovir resulted in arrest of proteinuria and stabilisation of renal function.

Forty-eight weeks treatment with clevudine 30 mg qd versus lamivudine 100 mg qd for chronic hepatitis B infection: a double-blind randomized study

BACKGROUND/AIMS

Clevudine is a pyrimidine analogue with potent activity against hepatitis B virus (HBV) replication in vitro. In a previous pivotal phase III clinical study, 24 weeks treatment with clevudine 30 mg has been shown to profoundly suppress HBV replication and normalize serum alanine aminotransferase level.

METHODS

In this study, we compare the efficacy and safety of clevudine (30 mg daily) versus lamivudine (100 mg daily) for 48 weeks in treatment-naive chronic hepatitis B e antigen (HBeAg) positive patients.

RESULTS

Ninety-two chronic HBeAg positive patients were randomized to receive clevudine 30 mg daily or lamivudine 100 mg daily in a 1:1 ratio. The clevudine group demonstrated greater viral suppression at week 48 when compared with the lamivudine group (median reduction: 4.27 vs. 3.17 log(10) copies/ml at week 48, p<0.0001). At week 48, serum HBV DNA level was below 300 copies/mL in 73% and 40% in the clevudine and lamivudine groups, respectively (p=0.001). HBeAg seroconversion occurred in 18% of patients in the clevudine group versus 12% in the lamivudine group at week 48. Lamivudine-resistant mutations were detected in 11 (24%) patients in the lamivudine group, who showed viral rebound during lamivudine therapy but no resistance was found in the clevudine group during 48-week treatment period.

CONCLUSIONS

A 48-week dosing with clevudine 30 mg daily was superior to lamivudine 100 mg daily in suppressing HBV replication, with no emergence of viral breakthrough in patients with HBeAg positive chronic hepatits B.

Detection of lamivudine- or adefovir-resistant hepatitis B virus mutations by a liquid array

A novel polymerase chain reaction (PCR)-Luminex assay was developed for rapid, accurate, and high-throughput detection of the most important hepatitis B virus (HBV) variants, including those with reverse transcriptase (RT) domain L180M, M204I/V, A181T/V/S, I233V and N236T mutations associated with resistance to lamivudine (LAM) or adefovir (ADV). Using mixtures of mutant and wild-type HBV, this method was sufficiently sensitive for detecting 10(3)HBV ml(-1) and could detect minor mutants when they comprised 5% of the total viral population. Comparison of the PCR-Luminex assay with INNO-LiPA for detecting clinical LAM- or ADV-resistant chronic hepatitis B virus infection in 64 patients confirmed the following: the 2 methods were 97.9% (48 of 49) and 93.3% (14 of 15) concordant for detecting LAM- or ADV-resistance mutations, respectively. The agreement with direct sequencing was 70.3% (45 of 64). The PCR-Luminex assay or multi-analyte suspension array can detect simultaneously and efficiently minor populations HBV mutants early during infection in many clinical samples. It is a simple, cost-effective method for resistance surveillance or selecting appropriate antiviral agents and initiating timely rescue treatment before the development drug-resistance related virus or biochemical breakthrough.

Molecular methods in the diagnosis and management of chronic hepatitis B

Chronic hepatitis B (CHB) infection remains a major global problem but the recent advances in molecular methods have revolutionized the diagnosis and management of CHB. Hepatitis B virus (HBV) DNA quantitation is the most useful molecular marker for the diagnosis and management of CHB. There is increasing evidence that the clinical outcome and efficacy of antiviral therapy for CHB could vary with the infecting HBV genotype, core promoter and precore mutations. Early identification of drug resistance is imperative in the management of CHB. The molecular methods for HBV DNA quantitation, HBV genotyping, the identification of mutants, genotypic and phenotypic methods for monitoring drug resistance and their utility and limitations for use in the diagnosis and monitoring of CHB are discussed in this article.

Chronic viral hepatitis in kidney transplantation

Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection in potential kidney transplant candidates-once considered absolute contraindications to kidney transplantation-no longer creates overt barriers to transplantation. Advances in the medical management of HBV and HCV infection have created opportunities for a substantial number of patients to be effectively treated with antiviral therapy before transplantation. For HBV infection, a number of new drugs enable clearance of the virus with minimal adverse effects and drug resistance. Pretransplantation antiviral therapy is advisable for patients with HCV infection, but adverse effects are common and viral eradication remains challenging. Regardless of viral clearance, pretransplant patients without bridging fibrosis (as confirmed by liver biopsy) or clinical stigmata of cirrhosis should be considered for kidney transplantation as survival is superior when compared to treatment with dialysis, and progression of liver disease is unlikely. For patients with advanced liver disease, simultaneous liver-kidney transplantation is an important consideration. These treatment advances further increase the burden of organ donor shortage; however, organs from deceased donors with chronic HBV or HCV infection could be efficiently allocated to certain individuals with a viral infection of the same type to increase the pool of available transplant organs.

Hepatitis B virus genotyping among chronic hepatitis B patients with resistance to treatment with lamivudine in the City of Ribeirão Preto, State of São Paulo

INTRODUCTION

Lamivudine is a nucleoside analogue that is used clinically for treating chronic hepatitis B infection. However, the main problem with prolonged use of lamivudine is the development of viral resistance to the treatment. Mutations in the YMDD motif of the hepatitis B virus DNA polymerase gene have been associated with resistance to drug therapy. So far, there have not been many studies in Brazil reporting on genotype-dependent development of resistance to lamivudine. Thus, the aim of the present study was to determine the possible correlation between a certain genotype and increased development of resistance to lamivudine among chronic hepatitis B patients.

METHODS

HBV DNA in samples from 50 patients under lamivudine treatment was amplified by means of conventional PCR. Samples were collected at Hospital das Clínicas, FMRP-USP. The products were then sequenced and phylogenetic analysis was performed.

RESULTS

Phylogenetic analysis revealed that 29 (58%) patients were infected with genotype D, 20 (40%) with genotype A and one (2%) with genotype F. Mutations in the YMDD motif occurred in 20% of the patients with genotype A and 27.6% of the patients with genotype D.

CONCLUSIONS

Despite the small number of samples, our results indicated that mutations in the YMDD motif were 1.38 times more frequent in genotype D than in genotype A.

Management of hepatitis B: Consensus of the Japan Society of Hepatology 2009

Recently, much progress has been made in the field of hepatitis B, such as natural history of the disease in relation to the amount of hepatitis B virus (HBV) DNA, genotypes of HBV influencing the natural course and treatment effects, mutations of HBV influencing the severity of the disease and development of hepatocellular carcinoma, and antiviral treatment such as nucleos(t)ide analogues and pegylated interferon. To make the consensus for the diagnosis, management and treatment of hepatitis B, a meeting was held during 45th annual meeting of Japan Society of Hepatology (JSH) in June 2009. In the meeting, recommendations and informative statements were discussed on the following subjects: (i) natural history of HBV infection; (ii) clinical implication of HBV genotypes; (iii) HBV mutations and their potential impact on pathogenesis of HBV infection; (iv) indications for antiviral treatment of chronic hepatitis B; (v) nucleos(t)ide analogues for chronic hepatitis B; and (vi) interferon therapy for chronic hepatitis B. The presenters reviewed the data on these subjects and proposed the consensus statements and recommendations. These statements were discussed among the organizers and presenters, and were approved by the participants of the meeting. In the current report, the relevant data were reviewed and the 12 consensus statements and nine recommendations on chronic hepatitis B were described.

Characterization of hepatitis virus B isolated from a multi-drug refractory patient

Prolonged treatment of chronic hepatitis B (CHB) with nucleoside analogues (NAs) almost invariably engenders viral resistance, and sequential NAs monotherapy can promote multi-drug resistance. This study aimed to investigate the molecular characteristics and the mutation profile of multi-drug resistant hepatitis B virus (HBV). The complete genome of HBV isolated from a multi-drug refractory patient was amplified and cloned, and 22 clones were selected for sequencing. The homology of the full-length genome between clones ranged from 98.7% to 99.9%. A precore stop codon mutation of G1896A and basic core promoter (BCP) mutations A1762T/G1764A were detected in a majority of clones. A phylogenetic analysis showed that all clones were classified as subgenotype B2. Three mutations in the surface (S) antigen region, sC76Y, sP120T and sI195M, were detected in 100%, 100% and 77.3% of the clones, respectively. In the core (C) antigen region, a mutation at codon 135 (cP135Q) was detected in 100% of clones. Lamivudine (LAM)-resistant mutations, rtL180M and rtM204V/I were detected in 86.4% of clones. Adefovir (ADV) or entecavir (ETV)-resistant mutations were not detected. Several novel mutations, such as rtT128N, rtA222T, rtS256G, rtL271M, rtS332R, and rtN/T337D, were present in a majority of clones. Furthermore, six pairs of mutations in the overlapping reverse transcriptase (RT) gene and S gene were detected. In conclusion, the complex HBV mutation profile detected in the multi-drug refractory patient highlights the problems associated with the ongoing selection of mutations, including further compensatory mutations as well as potential cross-resistance mutations.

Importance of serum concentration of adefovir for Lamivudine-adefovir combination therapy in patients with lamivudine-resistant chronic hepatitis B

Lamivudine (LMV)-adefovir pivoxil (ADV) combination therapy suppresses the replication of LMV-resistant hepatitis B virus (HBV), although its efficacy in suppressing HBV varies among patients. This study analyzed the clinical, virological, and pharmaceutical factors that influence the effect of the combination therapy. Patients negative for hepatitis B virus e antigen (HBeAg) and with low HBV DNA titers immediately prior to the combination therapy effectively cleared serum HBV DNA (P=0.0348 and P=0.0310, respectively). The maximum concentration of ADV in serum (ADV Cmax) was higher in patients who showed HBV DNA clearance (P=0.0392), and the cumulative clearance rates of HBV DNA were significantly higher in patients with ADV Cmax equal to or greater than 24 ng/ml (P=0.0284). HBeAg negativity and lower HBV DNA at the start of the combination therapy and higher ADV Cmax were found to be independent factors for serum HBV DNA clearance. Serum creatinine increased significantly during the combination therapy, and the ADV Cmax was higher in patients with low creatinine clearance rates. In conclusion, higher serum concentrations of ADV are associated with a good response to therapy based on clearance of HBV DNA in serum. However, care should be taken to prevent worsening of renal function due to high ADV serum concentrations.