Antiretroviral therapy for hepatitis B virus-HIV-coinfected patients: promises and pitfalls

Synthesis of novel entecavir analogues having 4'-cyano-6''-fluoromethylenecyclopentene skeletons as an aglycone moiety as highly potent and long-acting anti-hepatitis B virus agent

Encouraged by our recent findings that 4'-cyano-deoxyguanosine (2), entecavir analogues 4 and 5 are highly potent anti-hepatitis B virus (HBV) agents, we designed and synthesized 6 having a hybridized structure of 4 and 5. The chiral quaternary carbon portion at the 4'-position, which is substituted by cyano- and 5'-hydroxymethyl groups, was stereospecifically constructed by radical-mediated 5-exo-dig mode cyclization of 10. The introduction of the fluorine atom into the 6''-position was achieved by radical-mediated stannylation of sulfide (E)-11 and subsequent electrophilic fluorination of (E)-12. The desired (E)-6 was obtained after the introduction of the guanine base into (E)-18 under Mitsunobu conditions and following global deprotection. The stereoisomer (Z)-6 was also prepared by the same procedure using (Z)-12. Compound (E)-6 showed highly potent anti-HBV activity (EC₅₀ = 1.2 nM) with favorable cytotoxicity (CC₅₀ = 93 μM).

Undetectable Anti-HBs Antibodies: Need of a Booster Dose for HIV-1-Infected Individuals

HBV vaccination effectively prevents HBV transmission and the development of liver cancer. Disease progression and liver-related complications are more common in HIV-1/HBV co-infected than HBV mono-infected individuals. A considerable body of literature, which will be reviewed here, indicates that response to HBV vaccine is suboptimal in HIV-1-infected individuals and that the poor maintenance of protective immunity to HBV vaccines in these individuals is an important medical issue. Several factors affect HBV vaccine response during HIV-1 infection including CD4+ T cell counts, B cell response, vaccine formulation, schedules, and timing of antiretroviral therapy (ART). The initial response to HBV vaccination also plays a critical role in the sustainability of antibody responses in both HIV-1-infected and uninfected vaccinees. Thus, regular follow-up for antibody titer and a booster dose is warranted to prevent HBV transmission in HIV-1 infected people.

The prevalence of human immunodeficiency and of hepatitis B viral infections is not increased in patients with sickle cell disease in Tanzania

BACKGROUND

Tanzania ranks as the fourth country in the world with respect to the number of sickle cell disease (SCD) births; it is also endemic to the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV). This study was done to determine the prevalence of HIV and HBV infections among SCD patients in Dar es Salaam, Tanzania.

METHODS

A multicenter hospital-based descriptive cross sectional study was carried out among participants aged ≥ 16 years with a proven diagnosis of SCD. Socio-demographic and clinical data were recorded. Blood samples were drawn for HIV and HBV diagnosis. All categorical variables were summarized into frequencies.

RESULTS

There were 185/325 (56.9 %) females. The mean age (SD) was 23.0 ± 7.5 years. The prevalence of HIV was 1.8 %; the prevalence of HBV was 1.2 %.

CONCLUSIONS

The prevalence of both HIV and HBV in SCD patients is no greater than in the general population of Dar es Salaam or Tanzania. For associations, a large study would be needed. From a detailed blood transfusion history of SCD patients we found no evidence that HIV or HBV infection was transmitted through blood transfusion.

Integrating HIV Preexposure Prophylaxis With Community-Based Syringe Services for Women Who Inject Drugs: Results From the Project SHE Demonstration Study

INTRODUCTION

To guide future preexposure prophylaxis (PrEP) implementation for women who inject drugs (WWID), a population increasingly represented in new HIV cases in the United States, we present results from a demonstration project integrated within a syringe services program (SSP) in Philadelphia, PA.

METHODS

WWID ≥18 years were educated about and offered 24 weeks of daily PrEP. Participants completed surveys and clinical assessments at baseline and at weeks 1, 3, 12, and 24. We used descriptive statistics to estimate feasibility/acceptability, engagement in the care cascade, HIV/sexually transmitted diseases (STI) and pregnancy, issues of safety/tolerability, and preferences/satisfaction with PrEP services. Multivariable logistic regression with generalized estimating equations was used to identify factors associated with PrEP uptake and retention.

RESULTS

We recruited 136 WWID. Of those, 95 were included in the final sample, and 63 accepted a PrEP prescription at week 1. Uptake was associated with greater baseline frequency of SSP access [adjusted odds ratio (aOR) = 1.85; 95% confidence interval (CI): 1.24 to 2.77], inconsistent condom use (aOR = 3.38; 95% CI: 1.07 to 10.7), and experiencing sexual assault (aOR = 5.89; 95% CI: 1.02, 33.9). Of these 95, 42 (44.2%) were retained at week 24. Retention was higher among women who reported more frequent baseline SSP access (aOR = 1.46; 95% CI: 1.04 to 2.24). Self-reported adherence was high but discordant with urine-based quantification of tenofovir. Baseline STI prevalence was 17.9%; there were 2 HIV seroconversions and 1 pregnancy. Safety/tolerability issues were uncommon, and acceptability/satisfaction was high.

CONCLUSIONS

Integrating PrEP with SSP services is feasible and acceptable for WWID. This suggests that daily PrEP is a viable prevention tool for this vulnerable population.

Investigational drugs with dual activity against HBV and HIV (Review)

Chronic hepatitis B (CHB) and acquired immunodeficiency syndrome (AIDS) are global public health problems that pose a significant health burden. Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) coinfection is common, as these viruses have similar transmission routes, such as blood transmission, sexual transmission and mother-to-child transmission. Coinfection frequently leads to accelerated disease progression. For individuals coinfected with HIV/HBV, combination antiretroviral therapy containing dual anti-HBV drugs is recommended. Certain studies have also indicated the benefits of antiretroviral drugs with anti-HBV activity in patients with coinfection. A total of four Food and Drug Administration-approved HIV drugs also have anti-HBV activity; namely, emtricitabine, lamivudine, tenofovir disoproxil fumarate and tenofovir alafenamide, which are all nucleoside reverse transcriptase inhibitors. However, various issues, including drug resistance and side effects, limit their application. Therefore, it is necessary to develop more drugs with dual activity against HBV and HIV. The present review outlines the mechanisms, safety and efficacy of certain drugs that have been investigated for this purpose.

Hepatitis B infection and risk factors among children living with HIV in Yaounde, Cameroon: an integrated management

Background

The endemicity of hepatitis B virus (HBV) prompted the systematic immunization of newborns in Cameroon since 2005. In the frame of a considerable burden of HIV/HBV co-infection (17.5%), monitoring HBV among children living with HIV (CLHIV) would guide toward HIV/HBV integrated paediatric care. We sought to ascertain the prevalence and determinants of HBV infection in the population of CLHIV and performance of commonly used rapid diagnosis tests (RDTs).

Methods

Cross-sectional study conducted from February through June 2017 in a subset of CLHIV ≤15 years old at the Essos Hospital Centre, Yaounde, Cameroon. HBV was tested by HBsAg ELISA sandwich in duplicates for each sample, and the mean optical density was calculated. The Determinants of HBV-prevalencewere evaluated, and p < 0.05 was the significance threshold. The performance of two HBV RDTs (Diaspot vs. HBV-5) was evaluated in comparison to ELISA (used as gold standard).

Results

Of the 83 CLHIV enrolled (54.2% female, mean age 8.7 [±3.8] years, 60% vaccinated against HBV, all breastfed), HBV-prevalence was 2.41% (2/83). HBV-positivity was significantly associated with unknown maternal HBV status (2.9% [2/69] vs. 0.0% [0/14], p = 0.0097) and vaginal delivery (2.4% [2/82] vs. 0.0% [0/1], p = 0.0018). Moreover, the most likely to be positive were aged 11 and 15 years, and had experienced neither anti-HBV vaccination nor anti-HBV serum administration, and both had not been treated with any antiseptic solution at birth. Regarding the performance of Diaspot vs. HBV-5 respectively, sensitivity was 100% (2/2) vs. 50% (1/2), while specificity was 100% (45/45) vs. 97.8% (44/45); positive and negative predictive values of Diaspot versus HBV-5 were respectively 100% (2/2) and 100% (45/45) versus 50% (1/2) and 97.8% (44/45).

Conclusion

HBV-infection in the population of CLHIV appears at a moderate prevalence, suggesting a decreased burden likely due to preventive measures including the wide vaccine coverage. Focusing on mothers with unknown HBV status and promoting safer delivery mode (caesarean section) for HBV-positive motherswould contribute toward pediatric HBV elimination. In context of limited resources, Diaspot test appears more reliable to rollout HBV-infection in the population of CLHIV. As findings are limited to a small sample size, studies on a wider population would be relevant.

Multioutput Perturbation-Theory Machine Learning (PTML) Model of ChEMBL Data for Antiretroviral Compounds

Retroviral infections, such as HIV, are, until now, diseases with no cure. Medicine and pharmaceutical chemistry need and consider it a huge goal to define target proteins of new antiretroviral compounds. ChEMBL manages Big Data features with a complex data set, which is hard to organize. This makes information difficult to analyze due to a big number of characteristics described in order to predict new drug candidates for retroviral infections. For this reason, we propose to develop a new predictive model combining perturbation theory (PT) bases and machine learning (ML) modeling to create a new tool that can take advantage of all the available information. The PTML model proposed in this work for the ChEMBL data set preclinical experimental assays for antiretroviral compounds consists of a linear equation with four variables. The PT operators used are founded on multicondition moving averages, combining different features and simplifying the difficulty to manage all data. More than 140 000 preclinical assays for 56 105 compounds with different characteristics or experimental conditions have been carried out and can be found in ChEMBL database, covering combinations with 359 biological activity parameters (c₀), 55 protein accessions (c₁), 83 cell lines (c₂), 64 organisms of assay (c₃), and 773 subtypes or strains. We have included 150 148 preclinical experimental assays for HIV virus, 1188 for HTLV virus, 84 for simian immunodeficiency virus, 370 for murine leukemia virus, 119 for Rous sarcoma virus, 1581 for MMTV, etc. We also included 5277 assays for hepatitis B virus. The developed PTML model reached considerable values in sensibility (73.05% for training and 73.10% for validation), specificity (86.61% for training and 87.17% for validation), and accuracy (75.84% for training and 75.98% for validation). We also compared alternative PTML models with different PT operators such as covariance, moments, and exponential terms. Finally, we made a comparison between literature ML models with our PTML model and also artificial neural network (ANN) nonlinear models. We conclude that this PTML model is the first one to consider multiple characteristics of preclinical experimental antiretroviral assays combined, generating a simple, useful, and adaptable instrument, which could reduce time and costs in antiretroviral drugs research.

Impact of antiretroviral therapy containing tenofovir disoproxil fumarate on the survival of patients with HBV and HIV coinfection

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is active against both HBV and HIV. Whether the introduction of TDF-containing combination antiretroviral therapy (cART) has improved the outcome of HIV/HBV-coinfected patients remains unclear in areas of higher HBV endemicity.

METHODS

We retrospectively reviewed medical records of newly diagnosed antiretroviral-naïve HIV-infected patients between 2007 and 2015. Four groups of patients were defined, according to the HBV status and availability of TDF for HIV treatment in Taiwan in 2011. The primary outcome was all-cause mortality.

RESULTS

During the 9-year study period, 1,723 HIV-infected patients were included, with a median age of 31 years and baseline CD4 count of 273 cells per μL. The HBV seroprevalence had declined from 18.1% (125/692) in the pre-TDF era to 10.1% (104/1031) in the post-TDF era. The respective mortality rate for HIV/HBV-coinfected and HIV-monoinfected patients in the pre-TDF era was 23.2 (95% CI, 12.5-43.1) and 9.6 (95% CI, 6.1-15.0) deaths per 1000 person-years of follow-up [PYFU], and the respective mortality rate in the post-TDF era was 15.7 (95% CI, 7.0-34.8) and 8.0 (95% CI, 5.5-11.6) deaths per 1000 PYFU. The adjusted hazard ratio for mortality in multivariate Cox proportional-hazards regression analysis among HIV/HBV-coinfected patients compared to HIV-monoinfected patients was 2.79 (95% CI, 1.25-6.22) in pre-TDF era and 1.11 (95% CI, 0.45-2.72) in post-TDF era.

CONCLUSIONS

In this country of high HBV endemicity, the adverse impact of chronic HBV infection on the survival observed in the pre-TDF era has significantly diminished among HIV/HBV-coinfected patients compared to HIV-monoinfected patients in the era of TDF-containing cART.

CMCdG, a Novel Nucleoside Analog with Favorable Safety Features, Exerts Potent Activity against Wild-Type and Entecavir-Resistant Hepatitis B Virus

We designed, synthesized, and characterized a novel nucleoside analog, (1S,3S,5S)-3-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-5-hydroxy-1-(hydroxymethyl)-2-methylene-cyclopentanecarbonitrile, or 4'-cyano-methylenecarbocyclic-2'-deoxyguanosine (CMCdG), and evaluated its anti-hepatitis B virus (anti-HBV) activity, safety, and related features. CMCdG's in vitro activity was determined using quantitative PCR and Southern blotting assays, and its cytotoxicity was determined with a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, while its in vivo activity and safety were determined in human liver-chimeric mice infected with wild-type HBV genotype Ce (HBV_WT ^Ce) and an entecavir (ETV)-resistant HBV variant containing the amino acid substitutions L180M, S202G, and M204V (HBV_ETV-R ^{L180M/S202G/M204V}). CMCdG potently inhibited HBV production in HepG2.2.15 cells (50% inhibitory concentration [IC₅₀], ∼30 nM) and HBV_WT ^Ce plasmid-transfected Huh7 cells (IC₅₀, 206 nM) and efficiently suppressed ETV-resistant HBV_ETV-R ^{L180M/S202G/M204V} (IC₅₀, 2,657 nM), while it showed no or little cytotoxicity (50% cytotoxic concentration, >500 μM in most hepatocytic cells examined). Two-week peroral administration of CMCdG (1 mg/kg of body weight/day once a day [q.d.]) to HBV_WT ^Ce-infected human liver-chimeric mice reduced the level of viremia by ∼2 logs. CMCdG also reduced the level of HBV_ETV-R ^{L180M/S202G/M204V} viremia by ∼1 log in HBV_ETV-R ^{L180M/S202G/M204V}-infected human liver-chimeric mice, while ETV (1 mg/kg/day q.d.) completely failed to reduce the viremia. None of the CMCdG-treated mice had significant drug-related changes in body weights or serum human albumin levels. Structural analyses using homology modeling, semiempirical quantum methods, and molecular dynamics revealed that although ETV triphosphate (TP) forms good van der Waals contacts with L180 and M204 of HBV_WT ^Ce reverse transcriptase (RT), its contacts with the M180 substitution are totally lost in the HBV_ETV-R ^{L180M/S202G/M204V} RT complex. However, CMCdG-TP retains good contacts with both the HBV_WT ^Ce RT and HBV_ETV-R ^{L180M/S202G/M204V} RT complexes. The present data warrant further studies toward the development of CMCdG as a potential therapeutic for patients infected with drug-resistant HBV and shed light on the further development of more potent and safer anti-HBV agents.

The Safety of Tenofovir-Emtricitabine for HIV Pre-Exposure Prophylaxis (PrEP) in Individuals With Active Hepatitis B

Background:

Pre-exposure prophylaxis (PrEP) with daily oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) prevents HIV infection. The safety and feasibility of HIV PrEP in the setting of hepatitis B virus (HBV) infection were evaluated.

Methods:

The Iniciativa Profilaxis Pre-Exposición study randomized 2499 HIV-negative men and transgender women who have sex with men to once-daily oral FTC/TDF versus placebo. Hepatitis serologies and transaminases were obtained at screening and at the time PrEP was discontinued. HBV DNA was assessed by polymerase chain reaction, and drug resistance was assessed by population sequencing. Vaccination was offered to individuals susceptible to HBV infection.

Results:

Of the 2499 participants, 12 (0.5%; including 6 randomized to FTC/TDF) had chronic HBV infection. After stopping FTC/TDF, 5 of the 6 participants in the active arm had liver function tests performed at follow-up. Liver function tests remained within normal limits at post-stop visits except for a grade 1 elevation in 1 participant at post-stop week 12 (alanine aminotransferase = 90, aspartate aminotransferase = 61). There was no evidence of hepatic flares. Polymerase chain reaction of stored samples showed that 2 participants in the active arm had evidence of acute HBV infection at enrollment. Both had evidence of grade 4 transaminase elevations with subsequent resolution. Overall, there was no evidence of TDF or FTC resistance among tested genotypes. Of 1633 eligible for vaccination, 1587 (97.2%) received at least 1 vaccine; 1383 (84.7%) completed the series.

Conclusions:

PrEP can be safely provided to individuals with HBV infection if there is no evidence of cirrhosis or substantial transaminase elevation. HBV vaccination rates at screening were low globally, despite recommendations for its use, yet uptake and efficacy were high when offered.

THE PREVALENCE LIVER FUNCTION AND IMMUNOLOGIC STATUS OF CHILDREN WITH HIV AND HEPATITIS B VIRUS COINFECTION IN ENUGU, NIGERIA

BACKGROUND

Hepatitis B Virus (HBV) co-infection is prevalent among HIV infected individuals because of shared routes and mechanisms of transmission. The multidimensional immunosuppression from HIV infection causes impaired spontaneous recovery from an acute HBV infection, predisposing to chronic infection which is worsened by younger age at infection. Co-infection increases the risk of HBV replication, hepatotoxicity and liver related deaths from Highly Active Antiretroviral Therapy (HAART). The study was undertaken to highlight the burden of co-infection among HIV positive children in Enugu, determine the associated risk factors and compare the effect of co-infection between co-infected and non-co-infected children using liver enzyme and CD4 counts.

MATERIALS AND METHODS

A cross sectional study was carried out among HIV positive children attending the Paediatric ARV clinic of the University of Nigeria Teaching Hospital, Ituku-Ozalla. A total of 140 HIV infected children aged 18 months to 15 years were recruited. An interviewer questionnaire was administered. Hepatitis B surface antigen (HBsAg) was determined using Determine test Kit. Baseline and recent CD4 counts/CD4% were retrieved from the patients' folders.

RESULTS

Fourteen (10%) were positive for HBsAg. The highest prevalence of HBsAg was observed among children aged 11- 15 years. The higher the socioeconomic class the less likely the HBsAg positivity. Seven (50%) of the co-infected children had elevated baseline ALT compared with 57 (45.2%) of non-co-infected children though the difference was not statistically significant (t = 0.6, P = 0.56). After the initiation of HAART, 10 (76.9%) of the co-infected and 18 (15.1%) of the non-co-infected children had elevated ALT. The baseline median CD4 count among children ≥ 6 years was 230 cells/mm³ and 360 cells/mm³ respectively among the co-infected and non- co-infected, (P = 0.67). However, in children ≤ 5 years, it was 25% and 15 % respectively (P = 0.06).

CONCLUSION

HBV co-infection among HIV infected children is common in our environment, and co-infection is associated with impaired immunity and probably liver enzyme derangement.

4'-modified nucleoside analogs: potent inhibitors active against entecavir-resistant hepatitis B virus

Certain nucleoside/nucleotide reverse transcriptase (RT) inhibitors (NRTIs) are effective against human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV). However, both viruses often acquire NRTI resistance, making it crucial to develop more-potent agents that offer profound viral suppression. Here, we report that 4'-C-cyano-2-amino-2'-deoxyadenosine (CAdA) is a novel, highly potent inhibitor of both HBV (half maximal inhibitory concentration [IC50 ] = 0.4 nM) and HIV-1 (IC50  = 0.4 nM). In contrast, the approved anti-HBV NRTI, entecavir (ETV), potently inhibits HBV (IC50  = 0.7 nM), but is much less active against HIV-1 (IC50  = 1,000 nM). Similarly, the highly potent HIV-1 inhibitor, 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA; IC50  = 0.3 nM) is less active against HBV (IC50  = 160 nM). Southern analysis using Huh-7 cells transfected with HBV-containing plasmids demonstrated that CAdA was potent against both wild-type (IC50  = 7.2 nM) and ETV-resistant HBV (IC50  = 69.6 nM for HBVETV-RL180M/S202G/M204V), whereas ETV failed to reduce HBVETV-RL180M/S202G/M204V DNA even at 1 μM. Once-daily peroral administration of CAdA reduced HBVETV-RL180M/S202G/M204V viremia (P = 0.0005) in human-liver-chimeric/ HBVETV-RL180M/S202G/M204V-infected mice, whereas ETV completely failed to reduce HBVETV-RL180M/S202G/M204V viremia. None of the mice had significant drug-related body-weight or serum human-albumin concentration changes. Molecular modeling suggests that a shallower HBV-RT hydrophobic pocket at the polymerase active site can better accommodate the slightly shorter 4'-cyano of CAdA-triphosphate (TP), but not the longer 4'-ethynyl of EFdA-TP. In contrast, the deeper HIV-1-RT pocket can efficiently accommodate the 4'-substitutions of both NRTIs. The ETV-TP's cyclopentyl ring can bind more efficiently at the shallow HBV-RT binding pocket.

CONCLUSION

These data provide insights on the structural and functional associations of HBV- and HIV-1-RTs and show that CAdA may offer new therapeutic options for HBV patients.

HBV and HIV co-infection: Prevalence and clinical outcomes in tertiary care hospital Malaysia

According to WHO, Malaysia has been classified as a concentrated epidemic country due to progression of HIV infection in the population of injecting drug users. The main objectives of current study are to determine the prevalence of HBV among HIV-positive individuals in a tertiary care hospital of Malaysia and to assess the predictors involved in the outcomes of HIV-HBV co-infected patients. A retrospective, cross-sectional study is conducted at Hospital Palau Pinang, Malaysia. The collection of socio-demographic data as well as clinical data is done with the help of data collection form. Data were analyzed after putting the collected values of required data by using statistical software SPSS version 20.0 and P > 0.05 is considered as significant. Results show that the overall prevalence of HBV was 86 (13%) including 495 (74.5%) males and 169 (25.5%) females among a total of 664 HIV-infected patients. It was observed that there is a high prevalence of HIV-HBV co-infection in males 76 (11.4%) as compared to females 10 (1.5%) (P = 0.002). The median age of the study population was 39 years. The statistical significant risk factors involved in the outcomes of HIV-HBV co-infected patients were observed in the variables of gender, age groups, and injecting drug users. The findings of the present study shows that the prevalence of HBV infection among HIV-positive patients was 13% and the risk factors involved in the outcomes of HIV-HBV co-infected patients were gender, age, and intravenous drug users.

Hepatitis B vaccination for reducing morbidity and mortality in persons with HIV infection

BACKGROUND

Hepatitis B vaccine has been recommended for use in people living with HIV (PLHIV) mostly because of the similarities in routes of infection and their prevalence in the same geographic areas. PLHIV may not develop sero-protection after receiving standard hepatitis B vaccine due to their compromised immune status.

OBJECTIVES

To evaluate the efficacy of hepatitis B virus vaccine in PLHIV compared to placebo or no vaccine.

SEARCH METHODS

We searched 6 English language databases in July 2012, and updated the search in June 2013 and August 2014. We searched the grey literature, conference proceedings, specialised web sites, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials of hepatitis B vaccine compared to placebo or no vaccine, evaluating relevant outcomes of efficacy and safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on study design, participants, hepatitis B infection, hepatitis B related morbidity and mortality, anti-HBs immunogenicity and adverse effects related to vaccines from published articles or through correspondence with authors. Data were analysed qualitatively.

MAIN RESULTS

One double-blind randomised controlled trial with 26 participants who were on antiretroviral therapy (ART), comparing hepatitis B vaccine to placebo conducted in Spain met our eligibility criteria and was included in this review. The study ran for three years and participants were followed up on a monthly basis. The study reported adequate humoral response to vaccine at 12 months and no local or systematic side effects in both intervention and control groups. This humoral response was lost when the participants stopped taking ART. The sample size of the study was small and the study was conducted in a high income setting unlike the areas of highest burden of hepatitis B and HIV co-infections.

AUTHORS' CONCLUSIONS

The evidence from this study is insufficient to support any recommendations regarding the use of hepatitis B vaccine in PLHIV. Neither does this evidence demonstrate that hepatitis B vaccine is unsafe in PLHIV. Further randomised controlled trials in high prevalence areas are required to generate evidence on the long term efficacy and safety of hepatitis B vaccine in PLHIV with and without ART. Different regimens and routes of administration should also be explored.

Prevalence of hepatitis B co-infection amongst HIV infected children attending a care and treatment centre in Owerri, South-eastern Nigeria

INTRODUCTION

Hepatitis B infection impacts negatively on disease progression in HIV infected children thereby increasing morbidity and mortality. In spite of the foregoing, there is paucity of data on Hepatitis B co-infection in children living with HIV in Owerri, South Eastern Nigeria.This study set out to determine the prevalence of Hepatitis B Co- infection in HIV infected children attending the Paediatric HIV Care and Treatment clinic of the Federal Medical Centre Owerri.

METHODS

The study period was between February and July 2010. Testing for Hepatitis B infection was done using the ACON Hepatitis B surface antigen Rapid test strip. (Acon Laboratories Inc. San Diego.CA).

RESULTS

A total of 139 HIV infected children were enrolled during the study period. The overall prevalence of Hepatitis B Co- infection was 5.8% (8/139). The prevalence in males was 8.2% (5/61) while in females it was 3.8% (3/78). The prevalence of Hepatitis B Co- infection amongst patients on antiretroviral therapy was 4.6%. They accounted for 62.5% of Hepatitis B Co- infection in our study. Previous blood transfusion, gender and age of patient did not show statistically significant relationship with Hepatitis B Co-infection.

CONCLUSION

Though our study shows a low prevalence of Hepatitis B co infection in HIV infected children in our centre, reduction of the rate is still strongly desirable. Reduction can be achieved by strengthening the uptake of Hepatitis B vaccine as part of the routine childhood immunization programme.

Development and validation of a stability indicating method for seven novel derivatives of lamivudine with anti-HIV and anti-HBV activity in simulated gastric and intestinal fluids

A simple micellar liquid chromatography (MLC) method has been developed and validated for use in stability indicating studies of lamivudine and its carbonate derivatives with proved activity against human immunodeficiency and hepatitis B viruses (HIV and HBV, respectively), in simulated gastric (SGF) and intestinal (SIF) fluids samples. The optimized method involves a C18 column thermostated at 30°C, UV detection at 272 nm, a flow rate of 1.0 mL min(-1) and a micellar mobile phase composed by 0.15M sodium dodecyl sulphate (SDS) - 4% (v/v) 1-butanol - 0.01 M KH2PO4-Na2HPO4 (pH 7), using zidovudine (AZT) as internal standard. Validation under Food and Drug Administration (FDA) guideline of the analytical parameters include: linearity (r(2)>0.9996), LODs (1.6 × 10(-7)-6.9 × 10(-6)M) and LOQ (1 × 10(-5)M), intra (0.02-1.48%) and inter-day precision (0.04-1.66%) expressed as relative standard deviation (R.S.D.), and robustness parameters (less than 1.98%). Using this method, recoveries ranging from 92.9 to 119% were obtained for the eight substances. Thus, this method provides a simple, sensitive, accurate and precise assay for the determination of all compounds that can be readily adaptable to routine use by clinical laboratories with standard equipment. In addition, we evaluated the stability of carbonates of lamivudine in buffer pH 1.2 and 6.8; SGF (pH 1.2) and SIF one (pH 6.8), all as indicated in United States Pharmacopeia (USP) 32. Finally, this chromatographic method was applied to stability studies which resulted in all the compounds following a pseudo-first-order kinetics, and in the determination of its kinetic constant and half-life time.

Emergence of HBV resistance to lamivudine (3TC) in HIV/HBV co-infected patients in The Gambia, West Africa

BACKGROUND

Lamivudine (3TC) is a potent inhibitor of both Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV) replication and is part of first-line highly active antiretroviral therapy (HAART) in the Gambia. Unfortunately, the effectiveness of 3TC against HBV is limited by the emergence of resistant strains.

AIM

The aim of this retrospective study was to characterise 3TC-resistant mutations in HBV from co-infected patients receiving HAART, by generating HBV polymerase sequence data and viral loads from HBV genotype E infected patients, both at initiation and during a course of 3TC therapy.

METHOD

Samples from 21 HBV chronic carriers co-infected with HIV-1 (n = 18), HIV-2 (n = 2) and HIV-dual (n = 1) receiving HAART for a period of 6-52 months were analysed for the emergence of 3TC-resistance mutations.

FINDINGS

Sixteen out of 21 HBV/HIV co-infected patients responded well to HAART treatment maintaining suppression of HBV viraemia to low (≤ 104 copies/mL) (n = 5) or undetectable levels (< 260 copies/ml) (n = 11). Out of the 5 non-responders, 3 had developed 3TC-resistant HBV strains showing mutations in the YMDD motif at position 204 of the RT domain of the HBV polymerase. One patient showed the M204V+ L180M+ V173L+ triple mutation associated with a vaccine escape phenotype, which could be of public health concern in a country with a national HBV vaccination programme. All except one patient was infected with HBV genotype E.

CONCLUSIONS

Our findings confirm the risk of 3TC mutations in HAART patients following monotherapy. This is a novel study on 3TC resistance in HBV genotype E patients and encourage the use of tenofovir (in association with 3TC), which has not shown unequivocally documented HBV resistance to date, as part of first-line therapy in HIV/HBV co-infected patients in West Africa.HBV- hepatitis B infection; HIV- human immunodeficiency virus; HAART- antiretroviral therapy.

HIV/HBV Co-Infections: Epidemiology, Natural History, and Treatment: A Review Article

Hepatitis B virus (HBV) infection, one of the major health priorities, accounts approximately for 350 million chronic cases and a global total of 33 million people were living with human immunodeficiency virus (HIV) in the world.Co-infection with HIV and the HBV presents a significant challenge to health care providers, with different prevalence rates in different parts of the world. It is important to screen all HIV infected individuals for HBV infection and reverse. Infection with HBV becomes more violent in patients co-infected with human immunodeficiency syndrome. HIV/HBV co-infected individuals are at increased risk of chronic hepatitis, cirrhosis, and hepatocellular carcinoma, and of experiencing HAART toxicity. In this review, the latest statistics on epidemiology of HIV, HBV and their co-infection has been presented along with prominent characteristics of HBV. Transmission routes which are the common between HBV and HIV are described and the most important ones are described according to the regional and age features. Also, there is a series of actions being performed once HBV infections occur to prevent HIV or to diagnose if the HBV-infected individuals are also infected with HIV. As in treatment case, some of the frequent treatment methods including applying interferon and using nucleoside and nucleotide analogues have been discussed. Finally, we would explain the new recommendations for treating patients who were co-infected with HBV and HIV, including staging HBV and HIV treatment, based on the stage of each disease. It also outlines the optimal treatment options, whether the patient is treated for HBV first, HIV first, or HIV and HBV together.

HIV diagnostics: challenges and opportunities

Accurate HIV diagnostic testing continues to pose challenges, but there are also opportunities for assay performance improvements in key areas for specific intended-use settings. The genetic diversity of HIV can result in false and discordant results in assays that fail to detect new variant strains. The use of antiretroviral therapies has resulted in drug-resistant variants that require monitoring by sequencing and genotyping methods. Nucleic acid testing is the most sensitive and reliable platform for detection, but it is costly and limited to centralized testing facilities, making implementation difficult in resource-limited settings where HIV has hit the hardest. Rapid antibody tests suitable for point-of-care use are becoming more accessible in resource-limited settings, but these tests may not detect HIV during the acute infection stage. Emerging antigen/antibody combination assays are viable alternatives to nucleic acid testing for diagnosis of recent infections. Although patient monitoring (e.g., via CD4+ T-cell count and viral load determination) and infant diagnoses still rely on clinical laboratory-based testing, point-of-care options are being developed. There are other technical challenges to HIV diagnostic testing and emerging biodetection technologies that may be able to address them, but they are not yet proven.

Antiretroviral agents used by HIV-uninfected persons for prevention: pre- and postexposure prophylaxis

Prophylactic use of antimicrobial agents and microbicides has been proven for many infections, including surgical, gastrointestinal, upper respiratory, and meningococcal infections. Antiretroviral therapy for pregnant women prevents mother-to-child transmission of human immunodeficiency virus (HIV), which has become rare in settings where access to therapy is widespread. Postexposure prophylaxis after needlestick injury or significant sexual exposure is recommended on the basis of animal studies and case-control observational studies, although use of these interventions is limited to those who recognize exposure, have access, and have the power to use the interventions. Clinical trials are evaluating whether regular or preexposure use of antiretroviral therapy provides additional protection for persons at high risk of infection who are also offered standard prevention care, including HIV testing, counseling, condoms, and management of sexually transmitted infections. Trials are evaluating topical or oral use. Concerns have arisen with regard to optimal dosing strategies, costs, access, drug resistance, risk behavior, and the role of communities. Future implementation, if warranted, will be guided by the results of clinical trials in progress and engagement of communities exposed to HIV.

Hepatitis B vaccine responses in a large U.S. military cohort of HIV-infected individuals: another benefit of HAART in those with preserved CD4 count

The influence of highly active antiretroviral therapy (HAART) upon hepatitis B virus (HBV) vaccine responses in HIV-infected individuals is unclear. After classification of vaccinees as non-responders (HBsAb <10IU/L) or responders (HBsAb >or=10IU/L) in our HIV cohort, multivariate logistic regression was used to assess factors associated with subsequent vaccine response. Of 626 participants vaccinated from 1988 to 2005, 217 (35%) were vaccine responders. Receipt of >or=3 doses of vaccine (OR 1.83, 95% CI 1.24-2.70), higher CD4 count at vaccination (OR 1.09, 95% CI 1.05-1.13 per 50 cells/microl increase), and use of HAART (OR 2.37, 95% CI 1.56-3.62) were all associated with increased likelihood of developing a response. However, only 49% of those on HAART at last vaccination responded, and 62% of those on HAART, with CD4 count >or=350, and HIV RNA <400 copies/mL responded. Compared to those on HAART with CD4 count >or=350, those not on HAART with CD4 count >or=350 had significantly reduced odds of developing a vaccine response (OR 0.47, 95% CI 0.30-0.70). While HAART use concurrent with HBV immunization was associated with increased probability of responding to the vaccine, the response rate was low for those on HAART. These data provide additional evidence of HAART benefits, even in those with higher CD4 counts, but also highlight the need for improving HBV vaccine immunogenicity.

Cryptogenic liver disease in HIV-seropositive men

OBJECTIVES

In the era of highly active antiretroviral therapy (HAART), liver disease has become a leading cause of morbidity and mortality in HIV-seropositive individuals. Although liver disease is commonly caused by viral co-infection, it has also been described in patients without viral hepatitis. In this study, we determined clinical factors associated with the development of cryptogenic liver disease in HIV-infected individuals.

METHODS

HIV-seropositive and -seronegative patients undergoing evaluation for liver transplantation were selected if they met clinical criteria for cryptogenic liver disease. Clinical data were collected retrospectively, and radiological and histological data were reviewed separately.

RESULTS

Nine HIV-seropositive individuals were compared with 41 HIV-seronegative patients with cryptogenic liver disease. Only one HIV-seropositive patient (11%) had cirrhosis, compared to 39 HIV-seronegative patients (93%) (P<0.001). Three HIV-infected patients (33%) had histological evidence of nodular regenerative hyperplasia. HIV-seropositive patients had significantly lower body mass indices, and lower Child-Pugh-Turcotte and Model for Endstage Liver Disease scores than HIV-seronegative patients (P<0.05).

CONCLUSIONS

Advanced cryptogenic liver disease in HIV-infected patients is infrequently caused by cirrhosis, and more frequently by nodular regenerative hyperplasia. This disease entity may become more common in the HAART era, and may contribute to an increased morbidity in HIV-infected individuals.

Clinical significance of “anti-HBc alone” in human immunodeficiency virus-positive patients

AIM: To determine the prevalence and clinical relevance of isolated antibodies to hepatitis B core antigen as the only marker of infection (“anti-HBc alone”) among human immunodeficiency virus (HIV) type-1 infected patients. Occult hepatitis B infection frequency was also evaluated.

METHODS: Three hundred and forty eight histories from 2388 HIV-positive patients were randomly reviewed. Patients with serological markers of hepatitis B virus (HBV) infection were classified into three groups: past hepatitis, “anti-HBc alone” and chronic hepatitis. Determination of DNA from HBV, and RNA and genotype from hepatitis C virus (HCV) were performed on “anti-HBc alone” patients.

RESULTS: One hundred and eighty seven (53.7%) HIV-positive patients had markers of HBV infection: 118 past infection (63.1%), 14 chronic hepatitis (7.5%) and 55 “anti-HBc alone” (29.4%). Younger age [2.3-fold higher per every 10 years younger; 95% confidence intervals (CI) 1.33-4.00] and antibodies to HCV infection [odds ratio (OR) 2.87; 95% CI 1.10-7.48] were factors independently associated with the “anti-HBc alone” pattern. No differences in liver disease frequency were detected between both groups. Serum levels of anti-HBs were not associated with HCV infection (nor viral replication or HCV genotype), or with HIV replication or CD4 level. No “anti-HBc alone” patient tested positive for HBV DNA.

CONCLUSION: “Anti-HBc alone” prevalence in HIV-positive patients was similar to previously reported data and was associated with a younger age and with antibodies to HCV infection. In clinical practice, HBV DNA determination should be performed only in those patients with clinical or analytical signs of liver injury.

Co-infections and co-therapies: treatment of HIV in the presence of hepatitis C and hepatitis B

An increasing number of people are chronically infected with HIV and HCV, and/or HBV owing to shared routes of transmission. With the advent of HAART, liver disease secondary to hepatitis co-infections has emerged as a leading cause of morbidity and mortality in HIV-infected persons. There is increasing need to manage dual infection, but treatment is complicated by co-morbidities, overlapping toxicities, drug activities and resistance. A model of treatment that builds on the lessons learned from the treatment of HIV has evolved to maximize success of treating dual infections. This review will address current strategies for the management of HIV in the setting of HCV and HBV co-infection and discuss future treatment directions and challenges.

Liver enzymes improve over twenty-four months of first-line non-nucleoside reverse transcriptase inhibitor-based therapy in rural Uganda

We studied hepatic transaminases among rural Ugandans initiating highly active antiretroviral therapy (HAART) and assessed the impact of positive serology for hepatitis B surface antigen (HBsAg) and coadministration of therapy for tuberculosis. From July 2003 to December 2004, persons with symptomatic HIV disease or a CD4 count less than 250 cells/mm(3) and who had alanine transferase (ALT) or aspartate transferase (AST) less than 5 times the upper limit of normal were started on HAART including nevirapine (96%) or efavirenz (4%). Repository sera from a subset of 596 participants were analyzed for hepatic transaminase levels. A transaminase elevation was present before therapy for 249 (42%) of 596, at 3 months for 140 (25%) of 553, 12 months for 59 (11%) of 520, and 24 months for 67 (13%) of 508. In multivariate analyses, a transaminase elevation at 3 months was associated with male gender (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.02-2.35), body mass index less than 18 kg/m(2) (OR, 2.10; 95% CI, 1.34-3.30), transaminase elevation at baseline (OR, 1.97; 95% CI, 1.30-2.99), and treatment for tuberculosis (OR, 4.68; 95% CI, 2.28-9.59). HBsAg status was not associated with transaminase elevations at baseline or while on HAART. The prevalence of hepatic transaminase elevations decreased during non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy in this cohort of HIV-infected persons in rural Uganda.

Care of HIV patients with chronic hepatitis B: updated recommendations from the HIV-Hepatitis B Virus International Panel

Nearly 10% of the estimated 36 million people having HIV worldwide suffer from chronic hepatitis B virus (HBV) infection. The advent of new antiviral agents against HBV and the recent availability of improved molecular diagnostic tools have revolutioned the management of HIV/HBV coinfected patients. The present study represents an update of the current knowledge about HBV/HIV coinfection and an intent to provide practical advise about how to give the best care to HIV-infected persons with chronic hepatitis B.

Current treatment of HIV/hepatitis B virus coinfection

Coinfection with HIV and hepatitis B virus (HBV) has become a significant global health problem. Liver disease is now one of the leading causes of morbidity and mortality in individuals with HIV, particularly those with viral hepatitis. There are a number of agents available with dual activity against HIV and HBV, and effective treatment depends on understanding the potential advantages and pitfalls in using these agents. There are a number of unresolved issues in the management of HIV/HBV coinfection. These include the role of liver biopsy, the significance of normal aminotransferase levels, serum HBV DNA threshold for treatment, treatment end-points, and the treatment of HBV when HIV does not yet require treatment. Treatment of HBV should be considered in individuals with HIV/HBV coinfection with evidence of significant fibrosis (>/=F2), or with elevated serum HBV DNA levels (>2000 IU/mL). Sustained suppression of serum HBV DNA to below the level of detection by the most sensitive available assay should be the goal of therapy, and, at present, treatment of HBV in HIV/HBV coinfection is lifelong. If antiretroviral therapy is required, then two agents with anti-HBV activity should be incorporated into the regimen. If antiretroviral therapy is not required, then the options are pegylated interferon, adefovir or the early introduction of antiretroviral therapy. Close monitoring is necessary to detect treatment failure or hepatic flares, such as immune reconstitution disease. Further studies of newer anti-HBV agents in individuals HIV/HBV coinfection may advance treatment of this important condition.

Recent availability of two novel, fixed formulations of antiretroviral nucleoside analogues: a 12-month prospective, open-label survey of their practical use and therapeutic perspectives in antiretroviral-naive and -experienced patients

The recent introduction of novel, fixed nucleoside-nucleotide reverse transcriptase inhibitor (NRTI) combinations (tenofovir-emtricitabine, and abacavir-lamivudine) expanded the spectrum of available formulations and concurrently increased patients' adherence levels. A prospective survey of the open-label use of these two fixed combinations was performed in 158 patients belonging to our single-center cohort of more than 1,000 HIV-infected subjects enrolled in the last 18 months, and followed for at least 12 months. During the last 18 months, 95 consecutive, evaluable patients (60.1%) received for the first time tenofovir-emtricitabine, or abacavir-lamivudine (63 patients, 39.9%), and were followed for at least 12 months with periodic clinical and laboratory examinations. Among the 53 evaluable patients who were naïve to all antiretrovirals, tenofovir-emtricitabine has been given to 42 subjects (79.2%), mostly associated with efavirenz (26 cases), or different boosted protease inhibitors (16 subjects), whereas abacavir-lamivudine was administered to 11 patients (in 10 cases of 11, together with boosted protease inhibitors). In the remaining 105 patients, tenofovir-emtricitabine or abacavir-lamivudine therapy represented a switch from a prior combination antiretroviral regimen, and was predominantly associated with boosted protease inhibitors (61 patients), versus efavirenz or nevirapine (26 cases), or other drug combinations containing protease inhibitors (the remaining 18 patients). Among the 105 pretreated patients, the prescription of tenofovir-emtricitabine (53 patients) was as frequent as that of abacavir-lamivudine (52 cases), and the therapeutic change was primarily prompted by toxicity or poor tolerability (59 patients), followed by therapeutic failure and viral resistance (46 cases as a whole), and always encompassed a regimen simplification also. Both fixed combinations were well tolerated, and an adherence rate more than 90% was estimated among evaluable patients. From a tolerability point of view, the emtricitabine-tenofovir association was never withdrawn due to untoward events, while only two cases of early abacavir-lamivudine suspension occurred, due to a probable abacavir hypersensitivity reaction. From our preliminary experience, a major role seems to be played by tenofovir-emtricitabine in first-line treatments (preferably among "compact" regimens based on efavirenz), while the proportionally increased abacavir-lamivudine prescription to pretreated patients is mostly attributable to the different genetic barrier of abacavir (which was often associated with boosted protease inhibitors, in this last patient group). The present availability of two more fixed NRTI combinations favored by their single pill, once-daily administration strongly encourages randomized, controlled "head to head" studies in both first-line and experienced patents, in order to better exploit and target their therapeutic potential, and their most effective associations.

Entecavir exhibits inhibitory activity against human immunodeficiency virus under conditions of reduced viral challenge

Entecavir (ETV) was developed for the treatment of chronic hepatitis B virus (HBV) infection and is globally approved for that indication. Initial preclinical studies indicated that ETV had no significant activity against human immunodeficiency virus type 1 (HIV-1) in cultured cell lines at physiologically relevant ETV concentrations, using traditional anti-HIV assays. In response to recent clinical observations of anti-HIV activity of ETV in HIV/HBV-coinfected patients not receiving highly active antiretroviral therapy (HAART), additional investigative studies were conducted to expand upon earlier results. An extended panel of HIV-1 laboratory and clinical strains and cell types was tested against ETV, along with a comparison of assay methodologies and resistance profiling. These latest studies confirmed that ETV has only weak activity against HIV, using established assay systems. However, a >100-fold enhancement of antiviral activity (equivalent to the antiviral activity of lamivudine) could be obtained when assay conditions were modified to reduce the initial viral challenge. Also, the selection of a M184I virus variant during the passage of HIV-1 at high concentrations of ETV confirmed that ETV can exert inhibitory pressure on the virus. These findings may have a significant impact on how future assays are performed with compounds to be used in patients infected with HIV. These results support the recommendation that ETV therapy should be administered in concert with HAART for HIV/HBV-coinfected patients.

The implications of antiviral drugs with activity against hepatitis B virus and HIV

PURPOSE OF REVIEW

Around 10% of individuals infected with HIV suffer from chronic hepatitis B virus infection. This represents at least 4 million people worldwide. HIV infection modifies the course of hepatitis B virus associated liver disease with faster progression to cirrhosis. The number of anti-hepatitis B virus drugs has increased within the last few years, and some of them also exert activity against HIV-1. The aim of this article is to update the current knowledge on antiviral therapy for chronic hepatitis B in HIV-infected patients.

RECENT FINDINGS

In the absence of successful anti-hepatitis B virus therapy, morbidity and mortality associated with liver disease are increased in hepatitis B virus/HIV coinfected individuals. Data derived from studies using new more potent anti-hepatitis B virus drugs are very promising, and strategies to use these antivirals sequentially and/or in combination are being developed. Hopefully, this success will help bring a halt to liver-related complications and death in the hepatitis B virus/HIV coinfected population.

SUMMARY

Appropriate diagnosis and monitoring of chronic hepatitis B, including the use of noninvasive tools for assessing liver fibrosis, measurement of serum hepatitis B virus-DNA, and drug resistance testing, along with wise use of antivirals may convert hepatitis B virus/HIV coinfection into a manageable disease.

Current use of antiretroviral treatment

INTRODUCTION

Antiretroviral therapy for HIV infection has transformed it from a terminal illness to a chronic manageable condition. This review summarizes the history of the treatment and explains the current practice in the field, including uses in prevention strategies.

SOURCES OF DATA

National and international guidelines, important publications in peer reviewed literature and recent important conference abstracts.

AREAS OF AGREEMENT

There is a broad agreement on the choice of drug regimens and on the need to treat patients with symptomatic HIV infection and with CD4 cell counts less than 350 cells/mm(3). The need to adapt therapy to individual circumstances is also well accepted, e.g. hepatitis co-infection and pregnancy.

AREAS OF CONTROVERSY

Treatment of acute HIV infection and the optimum time to commence therapy in asymptomatic chronic infection remain controversial. Use of antiretrovirals for prevention, e.g. pre-exposure and post-exposure prophylaxis, is still developing.

GROWING POINTS

This article summarizes the current use of anti-HIV medication and the evidence behind it for the non-specialist.

AREAS TIMELY FOR DEVELOPING RESEARCH

New strategies for using current drugs, the best use of newly available drugs and new uses of antiretroviral drugs, such as in prevention of HIV transmission, are key areas for research. Further research addressing the question of when to start antiretrovirals and assessing their long-term effects is also needed.

Safety and tolerability of sequential pegylated IFN-alpha2a and tenofovir for hepatitis B infection in HIV(+) individuals

Chronic hepatitis B virus infections are a major cause of morbidity and mortality in HIV co-infected patients. The standard of care for treating HCV co-infection has been guided by major clinical trials, but the treatment of HBV co-infection has not been as thoroughly studied and the standard of care remains largely untested. The single pill formulation of tenofovir with emtricitabine has become a standard treatment approach in HBV co-infected patients. WU114 was a phase 1 clinical trial that examined the safety and tolerability of sequential treatment of HBV with pegylated interferon-alpha2a plus delayed-initiation tenofovir in HIV co-infected individuals. We postulated that initial HBV viral load reduction with pegylated interferon prior to initiation of nucleoside/nucleotide therapy would increase seroconversion events and durability of HBV virologic suppression. No severe pegylated IFN-alpha2a drug toxicities were seen in either the monotherapy or delayed tenofovir arms. Sequential pegylated interferon and tenofovir-based therapy was tolerable and should be compared with dual nucleoside/nucleotide suppression to determine relative frequencies of seroconversion and durability of HBV suppression in co-infected patients.

Sequential treatment with lamivudine and alpha-interferon in anti-HBe-positive chronic hepatitis B patients: a pilot study

BACKGROUND

In chronic hepatitis B, long-term use of alpha interferon is hampered by side effects, and long-term treatment with nucleos(t)ide analogues is burdened by drug-resistant mutants. We hypothesized that alternate rounds of lamivudine and alpha interferon might circumvent previous shortcomings.

AIM

To evaluate efficacy of sequential lamivudine or IFN-alpha2b monotherapies in preventing occurrence of tyrosine-methionine-aspartate-aspartate (YMDD) mutants and achieving virological and biochemical response.

METHODS

Fifteen patients with hepatitis B surface antigen, anti-HBe-positive chronic hepatitis received four consecutive rounds of monotherapy with lamivudine (100 mg/day), IFN-alpha2b (5MU/tiw), lamivudine, IFN-alpha2b. Serum HBV-DNA levels were evaluated during and off treatment, HBV polymerase and pre-core/core regions sequenced.

RESULTS

End-of-treatment response was achieved in 10 patients (67%). One patient did not respond, a second developed genotypic resistance at week 24. A rebound in viremia occurred in three patients at week 48. Six patients (40%) remained sustained responders. Triple promoter mutations at nucleotides 1762-1764-1896 prevailed in non-responders (60%) as compared to responders (20%). L180M/M204V mutations were identified during virological breakthrough.

CONCLUSION

Sequential approach of alternate rounds of lamivudine or interferon may help patients to tolerate a prolonged schedule of therapy and protect them from emergence of viral strains.

Low-dose tenofovir is more potent than adefovir and is effective in controlling HBV viremia in chronic HBeAg-negative hepatitis B

AIM: To study the efficacy of tenofovir disoproxil fumarate (TDF) at low dose in a small open trial of chronic hepatitis B patients with advanced stage disease.

METHODS: Eleven patients were treated with TDF 75 mg for a median period of 80 (range, 24-576) wk and then 7 cases were shifted to an adefovir 10 mg treatment group. All patients had been pre-treated with lamivudine: 5 had YMDD resistant mutants and 6 wild-type virus. When TDF was started, 4 patients had low-level viremia and 6 were PCR-negative.

RESULTS: During TDF treatment, PCR remained negative in 10 patients, transaminase levels were normal and no significant viral breakthrough was observed. The drug was well tolerated in all cases. When TDF 75 mg was substituted with adefovir 10 mg, 3 out of 7 patients had a persistent viral rebound (2700-130 000 copies/mL), in whom lamivudine had to be reintroduced.

CONCLUSION: Low-dose TDF monotherapy can control HBV viremia for an extended period of time without the emergence of resistance and is more potent than adefovir at the standard dosage. The use of a reduced dose of TDF could diminish the cost of therapy in low-income countries, but further studies in a larger population and in HBeAg-positive subjects are needed.

Impact of highly active antiretroviral therapy (HAART) on the natural history of hepatitis B virus (HBV) and HIV coinfection: relationship between prolonged efficacy of HAART and HBV surface and early antigen seroconversion

BACKGROUND

Coinfection with hepatitis B virus (HBV) in human immunodeficiency virus (HIV)-infected patients is common. However, little is known about the natural history of chronic hepatitis B in HIV-infected populations, especially the impact of highly active antiretroviral therapy (HAART) on the outcome of HBV early antigen (HBeAg) and HBV surface antigen (HBsAg) status.

METHODS

The characteristics of 92 patients coinfected with HIV and HBV were retrospectively assessed before and after HAART and lamivudine treatment to determine the impact of treatment on chronic hepatitis B and factors associated with HBeAg and/or HBsAg seroconversion.

RESULTS

During follow-up, 82 patients received antiretroviral therapy, 79 of whom received HAART. Twenty-eight of the 76 patients who were administered lamivudine therapy developed lamivudine resistance mutations. While receiving antiretroviral therapy, 10 of 59 HBeAg-positive patients developed antibody to HBeAg, 3 of 10 cleared HBsAg, and 2 of 3 developed antibody to HBsAg. Two of 23 HBeAg-negative patients cleared HBsAg and developed antibody to HBsAg. HBeAg and/or HBsAg seroconversion combined with an undetectable HBV DNA level (i.e., an HBV response) correlated with a sustained HIV response (P=.001), shorter duration of antiretroviral therapy (P=.058), and more-severe disease, as evaluated by Centers for Disease Control and Prevention staging (for stage B vs. stage A, P=.029; for stage C vs. stage A, P=.069). For patients with elevated baseline alanine aminotransferase levels, the HBV response correlated significantly with a greater increase in CD4 cell count while receiving HAART.

CONCLUSIONS

In HIV-HBV-coinfected patients, HBV response correlated with a sustained HIV response to antiretroviral therapy, usually HAART including lamivudine.

Tenofovir disoproxil fumarate for prevention of HIV infection in women: a phase 2, double-blind, randomized, placebo-controlled trial

OBJECTIVES

The objective of this trial was to investigate the safety and preliminary effectiveness of a daily dose of 300 mg of tenofovir disoproxil fumarate (TDF) versus placebo in preventing HIV infection in women.

DESIGN

This was a phase 2, randomized, double-blind, placebo-controlled trial.

SETTING

The study was conducted between June 2004 and March 2006 in Tema, Ghana; Douala, Cameroon; and Ibadan, Nigeria.

PARTICIPANTS

We enrolled 936 HIV-negative women at high risk of HIV infection into this study.

INTERVENTION

Participants were randomized 1:1 to once daily use of 300 mg of TDF or placebo.

OUTCOME MEASURES

The primary safety endpoints were grade 2 or higher serum creatinine elevations (>2.0 mg/dl) for renal function, grade 3 or 4 aspartate aminotransferase or alanine aminotransferase elevations (>170 U/l) for hepatic function, and grade 3 or 4 phosphorus abnormalities (<1.5 mg/dl). The effectiveness endpoint was infection with HIV-1 or HIV-2.

RESULTS

Study participants contributed 428 person-years of laboratory testing to the primary safety analysis. No significant differences emerged between treatment groups in clinical or laboratory safety outcomes. Study participants contributed 476 person-years of HIV testing to the primary effectiveness analysis, during which time eight seroconversions occurred. Two were diagnosed in participants randomized to TDF (0.86 per 100 person-years) and six in participants receiving placebo (2.48 per 100 person-years), yielding a rate ratio of 0.35 (95% confidence interval = 0.03-1.93), which did not achieve statistical significance. Owing to premature closures of the Cameroon and Nigeria study sites, the planned person-years of follow-up and study power could not be achieved.

CONCLUSION

Daily oral use of TDF in HIV-uninfected women was not associated with increased clinical or laboratory adverse events. Effectiveness could not be conclusively evaluated because of the small number of HIV infections observed during the study.

Tenofovir-induced kidney injury

Tenofovir disoproxil fumarate is a nucleotide reverse transcriptase inhibitor with activity against both HIV and the hepatitis B virus. It has had minimal nephrotoxic effects in early clinical trials, but as clinical use has widened, case reports describing tenofovir-induced renal tubular damage, Fanconi's syndrome and diabetes insipidus have been described. The authors review the pharmacokinetics, mechanism of action and clinical uses of tenofovir disoproxil fumarate. The large clinical trials, as well as the case reports of tenofovir-induced kidney injury, are also reviewed. The potential mechanism of renal damage is discussed and recommendations for evaluation and treatment of tenofovir-induced kidney injury are given.

Novel approaches towards conquering hepatitis B virus infection

Currently approved treatments for hepatitis B virus (HBV) infection include the immunomodulatory agent, IFN-α, and nucleos(t)ide analogues. Their efficacy is limited by their side effects, as well as the induction of viral mutations that render them less potent. It is thus necessary to develop drugs that target additional viral antigens. Chemicals and biomaterials by unique methods of preventing HBV replication are currently being developed, including novel nucleosides and newly synthesized compounds such as capsid assembling and mRNA transcription inhibitors. Molecular therapies that target different stages of the HBV life cycle will aid current methods to manage chronic hepatitis B (CHB) infection. The use of immunomodulators and gene therapy are also under consideration. This report summarizes the most recent treatment possibilities for CHB infection. Emerging therapies and their potential mechanisms, efficacy, and pitfalls are discussed.