Combination therapy with efavirenz, nelfinavir, and nucleoside reverse-transcriptase inhibitors in children infected with human immunodeficiency virus type 1. Pediatric AIDS Clinical Trials Group 382 Team

Impact of CYP2B6 genotype, tuberculosis therapy, and formulation on efavirenz pharmacokinetics in infants and children under 40 months of age

OBJECTIVE

Dosing efavirenz (EFV) in children less than 3 years of age is challenging due to large variability in drug levels. This study evaluated differences in pharmacokinetics with tuberculosis (TB) therapy, formulation, age, and CYP2B6 genotype.

DESIGN

Pharmacokinetic data from three IMPAACT/PACTG studies (P382, P1021, and P1070) for children initiating therapy less than 40 months of age were evaluated.

METHODS

Pharmacokinetic data were combined in a population pharmacokinetic model. Exposure from the 2-week pharmacokinetic visit was compared with changes in viral RNA between the Week 0 and Week 4 visits.

RESULTS

The model included 103 participants (19 on TB therapy). CYP2B6 516 genotype information was available for 82 participants (TT: 15, GT: 28, GG: 39). Median age at the first pharmacokinetic visit was 17.0 months (range: 2.0-39.0 months). Liquid formulation led to a 42% decrease in bioavailability compared with opened capsules. TB therapy (isoniazid and rifampin) led to a 29% decreased clearance, however Monte Carlo simulations demonstrated the majority of participants on TB therapy receiving standard EFV dosing to be in the target area under the curve range. Clearance was 5.3-fold higher for GG than TT genotype and 3.3-fold higher for GT than TT genotype. Age did not have a significant effect on clearance in the final model. Initial viral RNA decay was lower for patients in the lowest quartile of exposures (area under the curves) than for higher quartiles (P = 0.013).

CONCLUSION

EFV dosing should account for CYP2B6 516 genotype and formulation, but does not require adjustment for concurrent TB therapy.

Frequent Development of Broadly Neutralizing Antibodies in Early Life in a Large Cohort of Children With Human Immunodeficiency Virus

BACKGROUND

Recent studies have indicated that broadly neutralizing antibodies (bnAbs) in children may develop earlier after human immunodeficiency virus (HIV) infection compared to adults.

METHODS

We evaluated plasma from 212 antiretroviral therapy-naive children with HIV (1-3 years old). Neutralization breadth and potency was assessed using a panel of 10 viruses and compared to adults with chronic HIV. The magnitude, epitope specificity, and immunoglobulin (Ig)G subclass distribution of Env-specific antibodies were assessed using a binding antibody multiplex assay.

RESULTS

One-year-old children demonstrated neutralization breadth comparable to chronically infected adults, whereas 2- and 3-year-olds exhibited significantly greater neutralization breadth (P = .014). Likewise, binding antibody responses increased with age, with levels in 2- and 3-year-old children comparable to adults. Overall, there was no significant difference in antibody specificities or IgG subclass distribution between the pediatric and adult cohorts. It is interesting to note that the neutralization activity was mapped to a single epitope (CD4 binding site, V2 or V3 glycans) in only 5 of 38 pediatric broadly neutralizing samples, which suggests that most children may develop a polyclonal neutralization response.

CONCLUSIONS

These results contribute to a growing body of evidence suggesting that initiating HIV immunization early in life may present advantages for the development of broadly neutralizing antibody responses.

The Pharmacogenetics of Efavirenz Metabolism in Children: The Potential Genetic and Medical Contributions to Child Development in the Context of Long-Term ARV Treatment

Efavirenz (EFV) is a well-known, effective anti-retroviral drug long used in first-line treatment for children and adults with HIV and HIV/AIDS. Due to its narrow window of effective concentrations, between 1 and 4 μg/mL, and neurological side effects at supratherapeutic levels, several investigations into the pharmacokinetics of the drug and its genetic underpinnings have been carried out, primarily with adult samples. A number of studies, however, have examined the genetic influences on the metabolism of EFV in children. Their primary goal has been to shed light on issues of appropriate pediatric dosing, as well as the manifestation of neurotoxic effects of EFV in some children. Although EFV is currently being phased out of use for the treatment of both adults and children, we share this line of research to highlight an important aspect of medical treatment that is relevant to understanding the development of children diagnosed with HIV.

Neuropsychiatric symptoms in Tanzanian HIV-infected children receiving long-term efavirenz treatment: a multicentre, cross-sectional, observational study

BACKGROUND

Efavirenz is commonly prescribed for children with HIV infection, yet little is known about risks of neuropsychiatric side-effects. We aimed to compare competence (social involvement, activities, and school performance) and psychopathology (internalising and externalising problems), cognitive performance (intelligence and working memory), and adherence in Tanzanian children on an efavirenz-based versus a non-efavirenz-based regimen.

METHODS

In this multicentre, cross-sectional, observational study, we included consecutive children (aged 6-12 years) with HIV infection, on combination antiretroviral therapy (cART) for at least 6 months, and with viral loads of less than 1000 copies per mL from HIV care clinics of three primary health facilities and three referral hospitals in Moshi, Kilimanjaro, Tanzania. Children with acute illnesses, medication switch in the 6 months before the study visit, and any history of brain injury or developmental delay before cART initiation were excluded. All interviews and assessments were done by trained local research nurses under the supervision of a medical doctor. The primary outcomes, competence and psychopathology, were measured with the Child Behavior Checklist. We used ANCOVA to assess differences between groups. This study is registered with ClinicalTrials.gov, number NCT03227653.

FINDINGS

Between June 19, 2017, and Dec 14, 2017, 141 children were analysed, of whom 72 (51%) used efavirenz-based cART and 69 (49%) used non-efavirenz-based cART. After controlling for age, sex, and clinical and demographic confounders, we observed lower competence (adjusted mean difference -2·43 [95% CI -4·19 to -0·67], p=0·0071), largely driven by lower school performance scores (adjusted mean difference -0·91 [-1·42 to -0·40], p=0·00055), in the efavirenz group than in the non-efavirenz group. More total (adjusted mean difference 5·96 [95% CI -1·12 to 13·04], p=0·098) and internalising (adjusted mean difference 2·00 [-0·29 to 4·29], p=0·086) behavioural problems were seen in the efavirenz group than in the non-efavirenz group, although these findings were non-significant. No differences were found in externalising problems (adjusted mean difference 0·78 [95% CI -1·55 to 3·11], p=0·51).

INTERPRETATION

Our results suggest that treatment with efavirenz in children is associated with a mild increase in neuropsychiatric symptoms, especially in children who receive doses higher than or equal to the WHO recommended doses for efavirenz. Clinical awareness and adequate follow-up of neuropsychiatric symptoms in efavirenz in children remain warranted.

FUNDING

Aidsfonds, Radboud University Medical Center.

CYP2B6 Genetic Polymorphisms, Depression, and Viral Suppression in Adults Living with HIV Initiating Efavirenz-Containing Antiretroviral Therapy Regimens in Uganda: Pooled Analysis of Two Prospective Studies

Single-nucleotide polymorphisms (SNPs) in CYP2B6 have been shown to predict variation in plasma efavirenz concentrations, but associations between these SNPs and efavirenz-mediated depression and viral suppression are less well described. We evaluated three SNPs in CYP2B6 (rs3745274, rs28399499, and rs4803419) in Ugandan persons living with HIV. To define exposure, we used previously published pharmacokinetic modeling data to categorize participants as normal, intermediate, and poor efavirenz metabolizers. Our outcomes were probable depression in the first 2 years after antiretroviral therapy (ART) initiation (mean score of >1.75 on the Hopkins Symptom Depression Checklist) and viral suppression 6 months after ART initiation. We fit generalized estimating equation and modified Poisson regression models adjusted for demographic, clinical, and psychosocial characteristics with or without individuals with depression at the time of ART initiation. Among 242 participants, there were no differences in the pre-ART depression or viral load by efavirenz metabolism strata (p > .05). Participants were classified as normal (32%), intermediate (50%), and poor (18%) metabolizers. Seven percent (56/242) of follow-up visits met criteria for depression. Eighty-five percent (167/202) of participants who completed a 6-month visit achieved viral suppression. CYP2B6 metabolizer strata did not have a statistically significant association with either depression [adjusted risk ratio (aRR) comparing intermediate or poor vs. normal, 1.46; 95% confidence interval (CI), 0.72-2.95] or 6-month viral suppression (aRR, 1.01; 95% CI, 0.88-1.15). However, in analyses restricted to participants without pre-ART depression, poorer CYP2B6 metabolism was associated with increased odds of depression (adjusted odds ratio, 4.11; 95% CI, 1.04-16.20). Efavirenz-metabolizing allele patterns are strongly associated with risk of incident depression. Future work should elucidate further region-specific gene-environment interactions and whether alternate polymorphisms may be associated with efavirenz metabolism.

Plasma Efavirenz Exposure, Sex, and Age Predict Virological Response in HIV-Infected African Children

BACKGROUND

Owing to insufficient evidence in children, target plasma concentrations of efavirenz are based on studies in adults. Our analysis aimed to evaluate the pediatric therapeutic thresholds and characterize the determinants of virological suppression in African children.

METHODS

We analyzed data from 128 African children (aged 1.7-13.5 years) treated with efavirenz, lamivudine, and one among abacavir, stavudine, or zidovudine, and followed up to 36 months. Individual pharmacokinetic (PK) measures [plasma concentration 12 hours after dose (C12h), plasma concentration 24 hours after dose (C24h), and area under the curve (AUC0-24)] were estimated using population PK modeling. Cox multiple failure regression and multivariable fractional polynomials were used to investigate the risks of unsuppressed viral load associated with efavirenz exposure and other factors among 106 initially treatment-naive children, and likelihood profiling was used to identify the most predictive PK thresholds.

RESULTS

The risk of viral load >100 copies per milliliter decreased by 42% for every 2-fold increase in efavirenz mid-dose concentration [95% confidence interval (CI): 23% to 57%; P < 0.001]. The most predictive PK thresholds for increased risk of unsuppressed viral load were C12h 1.12 mg/L [hazard ratio (HR): 6.14; 95% CI: 2.64 to 14.27], C24h 0.65 mg/L (HR: 6.57; 95% CI: 2.86 to 15.10), and AUC0-24 28 mg·h/L (HR: 5.77; 95% CI: 2.28 to 14.58). Children older than 8 years had a more than 10-fold increased risk of virological nonsuppression (P = 0.005); among children younger than 8 years, boys had a 5.31 times higher risk than girls (P = 0.007). Central nervous system adverse events were infrequently reported.

CONCLUSIONS

Our analysis suggests that the minimum target C24h and AUC0-24 could be lowered in children. Our findings should be confirmed in a prospective pediatric trial.

Different Kinetics of Immunologic Recovery Using Nelfinavir or Lopinavir/Ritonavir-Based Regimens in Children with Perinatal HIV-1 Infection

The choice to include the optimal protease inhibitor (PI) in highly active antiretroviral therapy (HAART) regimens in children with perinatal HIV-1 infection is still under debate. Virologic and immunologic outcomes of three different regimens in an observational paediatric cohort were compared. Data from 12 saquinavir-, 18 nelfinavir-, and 10 lopinavir/ritonavir-treated children were analyzed after 4 and 24 weeks of therapy. Immunologic and virologic outcomes were compared using multivariate analysis adjusting the results for age, baseline CD4+ T-lymphocyte count and baseline viral load. Saquinavir-treated children displayed significant reduction in viral load at week 24 (but not at week 4) and no increase in CD4+ T-lymphocyte count, indicating a poor advantage in using this drug. Lopinavir/ritonavir-treated children presented lower viral loads than nelfinavir-treated children at week 4 (P=0.020) and week 24 (p<0.0001). Virologic failure occurred in 6/18 (33.3%) nelfinavir-treated children but in no child receiving lopinavir/ritonavir (P=0.013). An undetectable viral load was achieved in 9/10 (90.0%) lopinavir/ritonavir- vs. 3/18 (16.6%) nelfinavir-treated children (p<0.0001). No significant difference in CD4+ T-lymphocyte count was observed between lopinavir/ritonavir- and nelfinavir-treated children at weeks 4 and 24. However, a different kinetic of the immunologic recovery was observed. Lopinavir/ritonavir-treated children displayed higher CD4+ T-lymphocyte counts than saquinavir-treated children since the first month of therapy (week 4: P=0.042; week 24: P= 0.029) while nelfinavir-treated children took 24 weeks to reach such an outcome (P=0.034). Since lopinavir/ritonavir-based regimen controls viral replication more efficiently and restores CD4+ T-lymphocyte count more quickly than saquinavir- or nelfinavir-based HAART, it may be considered when a salvage therapy or a rapid increase in CD4+ T-lymphocytes is necessary.

Population Pharmacokinetics Analysis To Inform Efavirenz Dosing Recommendations in Pediatric HIV Patients Aged 3 Months to 3 Years

Efavirenz (EFV) is a nonnucleoside reverse transcriptase inhibitor approved worldwide for the treatment of HIV in adults and children over 3 years of age or weighing over 10 kg. Only recently EFV was approved in children over 3 months and weighing at least 3.5 kg in the United States and the European Union. The objective of this analysis was to support the selection of an appropriate dose for this younger pediatric population and to explore the impact of CYP2B6 genetic polymorphisms on EFV systemic exposures. A population pharmacokinetic (PPK) model was developed using data from three studies in HIV-1-infected pediatric subjects (n = 168) and one study in healthy adults (n = 24). The EFV concentration-time profile was best described by a two-compartment model with first-order absorption and elimination. Body weight was identified as a significant predictor of efavirenz apparent clearance (CL), oral central volume of distribution (VC), and absorption rate constant (Ka). The typical values of efavirenz apparent CL, VC, oral peripheral volume of distribution (VP), and Ka for a reference pediatric patient were 4.8 liters/h (4.5 to 5.1 liters/h), 84.9 liters (76.8 to 93.0 liters), 287 liters (252.6 to 321.4 liters), and 0.414 h(-1) (0.375 to 0.453 h(-1)), respectively. The final model was used to simulate steady-state efavirenz concentrations in pediatric patients weighing <10 kg to identify EFV doses that produce comparable exposure to adult and pediatric patients weighing ≥10 kg. Results suggest that administration of EFV doses of 100 mg once daily (QD) to children weighing ≥3.5 to <5 kg, 150 mg QD to children weighing ≥5 to <7.5 kg, and 200 mg QD to children weighing ≥7.5 to <10 kg produce exposures within the target range. Further evaluation of the impact of CYP2B6 polymorphisms on EFV PK showed that the identification of CYP2B6 genetic status is not predictive of EFV exposure and thus not informative to guide pediatric dosing regimens.

Neuropsychiatric complications of efavirenz in children with HIV infection

Efavirenz is an effective antiretroviral agent widely used as part of first-line regimen in HIV1-infected children and adults. Neuropsychiatric adverse effects are reported in up to 50% of users. These include dizziness, insomnia, abnormal dreams, headache and impaired concentration. The plasma level of efavirenz may be key in the development of these adverse effects. Even among individuals taking recommended doses for weight, the plasma levels vary widely. Genetic polymorphisms leading to different allelic variants of the CYP2B6 enzyme, making some individuals slow metabolizers may play a role. These allelic variants are highest in people of African descent. This report examines the neuropsychiatric adverse effects of efavirenz, and the strength of the data that the product may result in neuronal damage.

Rethinking the risk-benefit ratio of efavirenz in HIV-infected children

The non-nucleoside reverse transcriptase inhibitor efavirenz is part of the WHO guidelines for preferred first-line treatment of HIV-1-infected adults, pregnant and lactating women, and children. Efavirenz is well known to cause CNS toxicity. Although good data for CNS toxicity are available for adults, the opposite is true for children. Paediatric studies on this topic frequently suffer from small sample sizes or absence of thorough neuropsychiatric assessments. In this Personal View, we focus on two knowledge gaps of CNS toxicity of efavirenz in children. First, plasma concentrations of efavirenz are difficult to predict in children because of immaturity of and genetic variation in metabolic enzymes. Second, efavirenz exerts a lysergide (LSD)-like effect on brain serotonergic pathways and affects CNS metabolic pathways, including mitochondrial function. Whether these effects interfere with normal brain development is unknown. These uncertainties underline the imminent need for better monitoring of mental health and neurocognitive development in children given and exposed to efavirenz.

Efavirenz Capsule Sprinkle and Liquid Formulations With Didanosine and Emtricitabine in HIV-1-infected Infants and Children 3 Months to 6 Years of Age: Study AI266-922

BACKGROUND

AI266-922 was an open-label, dose-ranging study that assessed the pharmacokinetics, safety and efficacy of efavirenz (EFV) in children (3 months to 6 years).

METHODS

Antiretroviral-naïve and antiretroviral-experienced HIV-1-infected children received once-daily EFV as oral solution or capsule sprinkle plus didanosine and emtricitabine (FTC). Pharmacokinetic analyses were undertaken at week 2 and repeated at weeks 10 and 18 after an EFV dose change or switch from oral solution to capsule sprinkle.

RESULTS

Thirty-seven subjects were treated. EFV area under the plasma concentration-time curve over 1 dosing interval from time 0 to 24 hours postdose values were generally suboptimal (<110 μM × h) in subjects younger than 3 years treated with oral solution; these subjects switched to capsule sprinkle. Twenty of 21 subjects younger than 3 years treated with capsule sprinkle achieved an EFV area under the plasma concentration-time curve over 1 dosing interval from time 0 to 24 hours postdose value >110 μM × h, although higher initial doses were administered in this age group. Interpatient variability in EFV exposure was high. By week 48, 77.8% and 63.0% of subjects achieved HIV-RNA <400 and <50 copies/mL, respectively. Median changes in log10 HIV-RNA and CD4 percentage from baseline were -3.18 copies/mL and +6%, respectively. Two (5.4%) patients discontinued because of adverse events (AEs). Serious AEs occurred in 20 (54.1%) subjects. Common AEs were diarrhea (49%), nasopharyngitis (35%) and pneumonia (30%). Overall, 43% of subjects with suboptimal EFV exposure at week 2 developed resistance.

CONCLUSIONS

Once-daily EFV, given as capsule sprinkle, achieved target exposures in this study although doses were 2-3 times higher than Food and Drug Administration-approved doses for children younger than 3 years. These data are useful for dose selection modeling and simulation; however, Food and Drug Administration-approved doses should be used clinically. EFV + didanosine + FTC was efficacious with no new pediatric safety findings reported.

Efavirenz and the CNS: what we already know and questions that need to be answered

The NNRTI efavirenz has long been one of the most frequently employed antiretroviral drugs in the multidrug regimens used to treat HIV infection, in accordance with its well-demonstrated antiretroviral efficacy and favourable pharmacokinetics. However, growing concern about its adverse effects has sometimes led to efavirenz being replaced by other drugs in the initial treatment selection or to switching of therapy to efavirenz-free regimens in experienced patients. Neurological and neuropsychiatric reactions are the manifestations most frequently experienced by efavirenz-treated patients and range from transitory effects, such as nightmares, dizziness, insomnia, nervousness and lack of concentration, to more severe symptoms including depression, suicidal ideation or even psychosis. In addition, efavirenz has recently been associated with mild/moderate neurocognitive impairment, which is of specific relevance given that half of the patients receiving ART eventually suffer some form of HIV-associated neurocognitive disorder. The mechanisms responsible for efavirenz-induced neurotoxicity are unclear, although growing evidence points to disturbances in brain mitochondrial function and bioenergetics. This review offers a comprehensive overview of the current evidence on the interaction that efavirenz displays with the CNS, including the penetration and concentration of the drug in the brain. We discuss the prevalence, types and specificities of its side effects and recently uncovered cellular mechanisms that may be involved in their development.

Pharmacokinetics of Antiretrovirals Administered to HIV-Infected Children via Gastrostomy Tube

BACKGROUND

Surgical placement of a gastrostomy tube (g-tube) directly into a patient's gastrointestinal system to support antiretroviral administration is occasionally used to increase adherence in HIV-infected children. Absorption and distribution characteristics of antiretrovirals after g-tube administration, however, are unknown. The goal of this pilot study was to describe the pharmacokinetic characteristics of protease inhibitors (PIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) when administered to HIV-infected children via g-tube.

METHOD

Nine HIV-infected children who were receiving a PI- or NNRTI-containing regimen via g-tube were enrolled. All antiretrovirals (excluding efavirenz) were administered under direct observation for the pharmacokinetic evaluation. Blood samples were collected at predose and at 1, 2, 4, 8, and 12 hours postdose. Antiretroviral concentrations were measured in plasma using high performance liquid chromatography with ultraviolet detection.

RESULTS

Systemic exposure of PIs and NNRTIs in our 9 patients was similar to data from historical oral administration controls. Due to likely drug interactions, LPV exposure was decreased and one patient had low exposure of all antiretrovirals. When doses were increased, adequate exposure was attained.

CONCLUSION

This pilot study suggests that administration of most PIs and NNRTIs by a g-tube to HIV-infected children provides systemic exposure comparable with that achieved after oral administration.

Safety and effectiveness of combination antiretroviral therapy during the first year of treatment in HIV-1 infected Rwandan children: a prospective study

Background

With increased availability of paediatric combination antiretroviral therapy (cART) in resource limited settings, cART outcomes and factors associated with outcomes should be assessed.

Methods

HIV-infected children <15 years of age, initiating cART in Kigali, Rwanda, were followed for 18 months. Prospective clinical and laboratory assessments included weight-for-age (WAZ) and height-for-age (HAZ) z-scores, complete blood cell count, liver transaminases, creatinine and lipid profiles, CD4 T-cell count/percent, and plasma HIV-1 RNA concentration. Clinical success was defined as WAZ and WAZ >−2, immunological success as CD4 cells ≥500/mm³ and ≥25% for respectively children over 5 years and under 5 years, and virological success as a plasma HIV-1 RNA concentration <40 copies/mL.

Results

Between March 2008 and December 2009, 123 HIV-infected children were included. The median (interquartile (IQR) age at cART initiation was 7.4 (3.2, 11.5) years; 40% were <5 years and 54% were female. Mean (95% confidence interval (95%CI)) HAZ and WAZ at baseline were −2.01 (−2.23, −1.80) and −1.73 (−1.95, −1.50) respectively and rose to −1.75 (−1.98, −1.51) and −1.17 (−1.38, −0.96) after 12 months of cART. The median (IQR) CD4 T-cell values for children <5 and ≥5 years of age were 20% (13, 28) and 337 (236, 484) cells/mm³respectively, and increased to 36% (28, 41) and 620 (375, 880) cells/mm³. After 12 months of cART, 24% of children had a detectable viral load, including 16% with virological failure (HIV-RNA>1000 c/mL). Older age at cART initiation, poor adherence, and exposure to antiretrovirals around birth were associated with virological failure. A third (33%) of children had side effects (by self-report or clinical assessment), but only 9% experienced a severe side effect requiring a cART regimen change.

Conclusions

cART in Rwandan HIV-infected children was successful but success might be improved further by initiating cART as early as possible, optimizing adherence and optimizing management of side effects.

Antiretroviral treatment in HIV-1 infected pediatric patients: focus on efavirenz

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI), used for the treatment of human immunodeficiency virus (HIV)-1 infection. Approved by the US Food and Drug Administration in 1998, its indication was recently extended to include children as young as 3 months of age. The World Health Organization and many national guidelines consider efavirenz to be the preferred NNRTI for first-line treatment of children over the age of 3 years. Clinical outcomes of patients on three-drug antiretroviral regimens which include efavirenz are as good as or better than those for patients on all other currently approved HIV medications. Efavirenz is dosed once daily and has pediatric-friendly formulations. It is usually well tolerated, with central nervous system side effects being of greatest concern. Efavirenz increases the risk of neural tube defects in nonhuman primates and therefore its use during the first trimester of pregnancy is limited in some settings. With minimal interactions with antituberculous drugs, efavirenz is preferred for use among patients with HIV/tuberculosis coinfection. Efavirenz can be rendered inactive by a single point mutation in the reverse transcriptase enzyme. Newer NNRTI drugs such as etravirine, not yet approved for use in children under the age of 6 years, may maintain their activity following development of efavirenz resistance. This review highlights key points from the existing literature regarding the use of efavirenz in children and suggests directions for future investigation.

Etravirine in treatment-experienced, HIV-1-infected children and adolescents: 48-week safety, efficacy and resistance analysis of the phase II PIANO study

OBJECTIVES

PIANO (Paediatric study of Intelence As an NNRTI Option; TMC125-C213; NCT00665847) assessed the safety/tolerability, antiviral activity and pharmacokinetics of etravirine plus an optimized background regimen (OBR) in treatment-experienced, HIV-1-infected children (≥ 6 to < 12 years) and adolescents (≥ 12 to < 18 years) over 48 weeks.

METHODS

In a phase II, open-label, single-arm study, 101 treatment-experienced patients (41 children; 60 adolescents) with screening viral load (VL) ≥ 500 HIV-1 RNA copies/mL received etravirine 5.2 mg/kg (maximum dose 200 mg) twice a day (bid) plus OBR.

RESULTS

Sixty-seven per cent of patients had previously used efavirenz or nevirapine. At week 48, the most common treatment-related grade ≥ 2 adverse event (AE) was rash (13%); 12% experienced grade 3 AEs. Only two grade 4 AEs occurred (both thrombocytopaenia, not etravirine related). At week 48, 56% of patients (68% children; 48% adolescents) achieved a virological response (VL<50 copies/mL; intent-to-treat, noncompleter=failure). Factors predictive of response were adherence > 95%, male sex, low baseline etravirine weighted genotypic score and high etravirine trough concentration (C0h ). Seventy-six patients (75%) completed the trial; most discontinuations occurred because of protocol noncompliance or AEs (8% each). Sixty-five per cent of patients were > 95% adherent by questionnaire and 39% by pill count. Forty-one patients experienced virological failure (VF; time-to-loss-of-virological-response non-VF-censored algorithm) (29 nonresponders; 12 rebounders). Of 30 patients with VF with paired baseline/endpoint genotypes, 18 (60%) developed nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations, most commonly Y181C. Mean etravirine area under the plasma concentration-time curve over 12 h (AUC0-12h ; 5216 ng h/mL) and C0h (346 ng/mL) were comparable to adult target values.

CONCLUSIONS

Results with etravirine 5.2 mg/kg bid (with OBR) in this treatment-experienced paediatric population and etravirine 200 mg bid in treatment-experienced adults were comparable. Etravirine is an NNRTI option for treatment-experienced paediatric patients.

Pharmacometric characterization of efavirenz developmental pharmacokinetics and pharmacogenetics in HIV-infected children

The aim of this analysis was to create a pharmacometric model of efavirenz developmental pharmacokinetics and pharmacogenetics in HIV-infected children. The data consisted of 3,172 plasma concentrations from 96 HIV-1-infected children who participated in the Pediatric AIDS Clinical Trials Group 382 (PACTG382) study. Analyses were performed using NONMEM, and the impacts of body weight, age, race, sex, formulation, liver function, and cytochrome P450 2B6 (CYP2B6)-G516T and multidrug-resistance transporter gene (MDR1)-C3435T polymorphisms were assessed. A one-compartment model using weight-based allometry on oral clearance and apparent volume of distribution adequately described the data. A sigmoid maximum-effect (Emax) maturation model demonstrated an increase in oral clearance with age to reach 90% of its mature level by the age of 9 months. The liquid formulation bioavailability relative to the capsule was found to increase with age to reach 90% of its mature value by the age of 8 years. The CYP2B6-G516T polymorphism decreased oral clearance, while the MDR1-C3435T polymorphism demonstrated no effect.

Effects of rifampin-based antituberculosis therapy on plasma efavirenz concentrations in children vary by CYP2B6 genotype

OBJECTIVES

An efavirenz-based antiretroviral therapy (ART) regimen is preferred for children more than 3 years of age with tuberculosis. However, rifampin, a key component of antituberculosis therapy, induces CYP2B6. An increased dose of efavirenz is recommended in adults weighing more than 50 kg who require rifampin, but there is scant information in children being treated for tuberculosis.

DESIGN

Plasma efavirenz concentrations were compared in 40 children during concomitant treatment for tuberculosis and HIV-1, after stopping rifampicin, and in a control group of children without tuberculosis. Associations with antituberculosis treatment, metabolizer genotype (based on CYP2B6 516G→T, 983T→C, and 15582C→T), weight, and time after dose were evaluated.

RESULTS

Compared to children with extensive metabolizer genotypes, efavirenz concentrations were increased 1.42-fold (95% confidence interval, CI 0.94–2.15) and 2.85-fold (95% CI 1.80–4.52) in children with intermediate and slow metabolizer genotypes, respectively. Concomitant antituberculosis treatment increased efavirenz concentrations 1.49-fold (95% CI 1.10–2.01) in children with slow metabolizer genotypes, but did not affect efavirenz concentrations in extensive or intermediate metabolizer genotypes. After adjustment for dose/kg, each kilogram of weight was associated with a 2.8% (95% CI 0.9–4.7) decrease in efavirenz concentrations. Despite higher milligram per kilogram doses, a higher proportion of children in the lowest weight band (10–13.9 kg) had efavirenz concentrations less than 1.0 mg/l than larger children.

CONCLUSION

Antituberculosis treatment was not associated with reduced efavirenz concentrations in children, which does not support increased efavirenz doses. Children with slow metabolizer genotype have increased efavirenz concentrations during antituberculosis treatment, likely due to isoniazid inhibiting enzymes involved in accessory metabolic pathways for efavirenz.

Rate of candidiasis among HIV-infected children in Spain in the era of highly active antiretroviral therapy (1997-2008)

BACKGROUND

Candidiasis is the most common opportunistic infection seen in human immunodeficiency virus (HIV)-infected individuals. The aim of our study was to estimate the candidiasis rate and evaluate its trend in HIV-infected children in Spain during the era of highly active antiretroviral therapy (HAART) compared to HIV-uninfected children.

METHODS

We carried out a retrospective study. Data were obtained from the records of the Minimum Basic Data Set from hospitals in Spain. All HIV-infected children were under 17 years of age, and a group of HIV-uninfected children with hospital admissions matching the study group by gender and age were randomly selected. The follow-up period (1997-2008) was divided into three calendar periods: a) From 1997 to 1999 for early-period HAART; b) from 2000 to 2002 for mid-period HAART; and c) from 2003 to 2008 for late-period HAART.

RESULTS

Among children with hospital admissions, HIV-infected children had much higher values than HIV-uninfected children during each of the three calendar periods for overall candidiasis rates (150.0 versus 6.1 events per 1,000 child hospital admissions/year (p < 0.001), 90.3 versus 3.1 (p < 0.001), and 79.3 versus 10.7 (p < 0.001), respectively) and for non-invasive Candida mycosis (ICM) rates (118.5 versus 3.8 (p < 0.001), 85.3 versus 2.3 (p < 0.001), and 80.6 versus 6.0 (p < 0.001), respectively). In addition, HIV-infected children also had higher values of ICM rates than HIV-uninfected children, except during the last calendar period when no significant difference was found (32.4 versus 1.2 (p < 0.001), 11.6 versus 0.4 (p < 0.001), and 4.6 versus 2.3 (p = 0.387), respectively). For all children living with HIV/AIDS, the overall candidiasis rate (events per 1,000 HIV-infected children/year) decreased from 1997-1999 to 2000-2002 (18.8 to 10.6; p < 0.001) and from 2000-2002 to 2003-2008 (10.6 to 5.7; p = 0.060). Within each category of candidiasis, both non-ICM and ICM rates experienced significant decreases from 1997-1999 to 2003-2008 (15.9 to 5.7 (p < 0.001) and 4.1 to 0.3 (p < 0.001), respectively).

CONCLUSIONS

Although the candidiasis rate still remains higher than in the general population (from 1997 to 2008), candidiasis diagnoses have decreased among HIV-infected children throughout the HAART era, and it has ceased to be a major health problem among children with HIV infection.

Effectiveness of efavirenz-based regimens in young HIV-infected children treated for tuberculosis: a treatment option for resource-limited settings

BACKGROUND

Antiretroviral treatment (ART) options for young children co-infected with HIV and tuberculosis are limited in resource-poor settings due to limited data on the use of efavirenz (EFV). Using available pharmacokinetic data, an EFV dosing schedule was developed for young co-infected children and implemented as the standard of care at Macha Hospital in Southern Province, Zambia. Treatment outcomes in children younger than 3 years of age or weighing less than 10 kg receiving either EFV-based ART plus anti-tuberculous treatment or nevirapine-based (NVP) ART were compared.

METHODS

Treatment outcomes were measured in a cohort of HIV-infected children seeking care at Macha Hospital in rural Zambia from 2007 to 2010. Information on the diagnosis and treatment of tuberculosis was abstracted from medical records.

RESULTS

Forty-five children treated for tuberculosis initiated an EFV-based regimen and 69 children initiated a NVP-based regimen, 7 of whom also were treated for tuberculosis. Children receiving both regimens were comparable in age, but children receiving EFV started ART with a lower CD4(+) T-cell percentage and weight-for-age z-score. Children receiving EFV experienced increases in both CD4(+) T-cell percentage and weight-for-age z-score during follow-up, such that levels were comparable to children receiving NVP after two years of ART. Cumulative survival after 12 months of ART did not differ between groups (NVP:87%;EFV:80%;p = 0.25). Eleven children experienced virologic failure during follow-up.The adjusted hazard ratio of virologic failure comparing EFV to NVP was 0.25 (95% CI:0.05,1.24) and 0.13 (95% CI:0.03,0.62) using thresholds of 5000 and 400 copies/mL, respectively.Five children receiving EFV were reported to have had convulsions after ART initiation compared to only one child receiving NVP (p = 0.04).

CONCLUSIONS

Despite poorer health at ART initiation, children treated for tuberculosis and receiving EFV-based regimens showed significant improvements comparable to children receiving NVP-based regimens. EFV-based regimens should be considered for young HIV-infected children co-infected with tuberculosis in resource-limited settings.

Quantification of CD4 responses to combined antiretroviral therapy over 5 years among HIV-infected children in Kinshasa, Democratic Republic of Congo

BACKGROUND

The long-term effects of combined antiretroviral therapy (cART) on CD4 percentage in HIV-infected children are incompletely understood, with evidence from resource-deprived areas particularly scarce even though most children with HIV live in such settings. We sought to describe this relationship.

METHODS

Observational longitudinal data from cART-naive children enrolled between December 2004 and May 2010 into an HIV care and treatment program in Kinshasa, Democratic Republic of Congo were analyzed. To estimate the effect of cART on CD4 percentage while accounting for time-dependent confounders affected by prior exposure to cART, a marginal structural linear mean model was used.

RESULTS

Seven hundred ninety children were active for 2090 person-years and a median of 31 months; 619 (78%) initiated cART. At baseline, 405 children (51%) were in HIV clinical stage 3 or 4; 528 (67%) had advanced or severe immunodeficiency. Compared with no cART, the estimated absolute rise in CD4 percentage was 6.8% [95% confidence interval (CI), 4.7% to 8.9%] after 6 months of cART, 8.6% (95% CI, 7.0% to 10.2%) after 12 months, and 20.5% (95% CI, 16.1% to 24.9%) after 60 months. cART-mediated CD4 percentage gains were slowest but greatest among children with baseline CD4 percentage <15. The cumulative incidence of recovery to "not significant" World Health Organization age-specific immunodeficiency was lower if cART was started when immunodeficiency was severe rather than mild or advanced.

CONCLUSIONS

cART increased CD4 percentages among HIV-infected children in a resource-deprived setting, as previously noted among children in the United States. More gradual and protracted recovery in children with lower baseline CD4 percentages supports earlier initiation of pediatric cART.

Monitoring of HIV type 1 DNA load and drug resistance in peripheral blood mononuclear cells during suppressive antiretroviral therapy does not predict virologic failure

Our objective was to determine whether monitoring HIV-1 DNA concentration or new resistance mutations in peripheral blood mononuclear cells (PBMCs) during effective antiretroviral therapy (ART) predicts virologic failure. A retrospective analysis used blood specimens and clinical data from three nevirapine containing arms of a four-arm, open-label, randomized trial comparing ART regimens in HIV-1-infected children who had failed mono- or dual-nucleoside therapy. Sensitive assays compared cell-associated HIV-1 DNA concentrations and nevirapine (NVP) and lamivudine (3TC) resistance mutations in children with plasma HIV-1 RNA <400 copies(c)/ml who did or did not experience subsequent virologic failure. Forty-six children were analyzed through the last available follow-up specimen, collected at 48 (n=16) or 96 (n=30) weeks of ART. Thirty-five (76%) had sustained viral suppression and 11 (24%) had plasma viral rebound to ≥ 400 c/ml (virologic failure detected at a median of 36 weeks). HIV-1 DNA levels at baseline, 24, 48, and 96 weeks of ART were similar in children who did vs. did not experience virologic failure (p=0.82). HIV-1 DNA levels did not increase prior to viral rebound. NVP resistance mutations were detected in 91% of subjects in the failure group vs. 3% in the suppressed group (p <0.0001). Among nine evaluable children, NVP mutations were first detected prior to virologic failure in two (22%), at viral rebound in five (56%), and after failure in two (22%) children. HIV-1 DNA concentrations did not predict virologic failure in this cohort. New drug resistance mutations were detected in the PBMCs of a minority of virologically suppressed children who subsequently failed ART.

Efavirenz-induced exfoliative dermatitis

Individuals with a human immunodeficiency virus (HIV) infection are at higher risk of developing adverse drug reactions. Multiple drugs are usually prescribed to patients with HIV infection for preventing the replication of HIV and for the treatment of the associated opportunistic infections. We report here the first case of an HIV-1-infected patient who developed an exfoliative dermatitis induced by efavirenz, a non-nucleoside reverse transcriptase inhibitor. Physicians should be aware of the possible occurrence of efavirenz-induced skin eruptions from the start of antiviral treatment of HIV infection.

Adherence to antiretroviral therapy and its correlates among HIV-infected children at an HIV clinic in New Delhi

BACKGROUND

With the introduction of antiretroviral therapy (ART), the mortality and morbidity of HIV/AIDS have decreased markedly. However, high adherence to ART (>95%) is necessary for a good therapeutic outcome. There is a paucity of data on paediatric adherence to ART and its correlates from developing countries, particularly India.

AIM

To determine the rate of adherence to ART in HIV-infected Indian children and the factors associated with adherence.

METHODS

A cross-sectional study was conducted at an ART clinic in New Delhi, north India. Caregivers of 90 children were interviewed using a pre-designed, structured questionnaire and checklist. The primary measure of adherence was 4-day caregiver's recall. Adherence rates were correlated with 3-monthly CD4 counts.

RESULTS

Mean (SD, range) adherence was 91·4% (12·3, 75-100%). Adherence was low (<95%) in 31 (34·4%) patients. On multivariate logistic regression analysis, increasing time since ART initiation (OR 1·08, 95% CI 1·02-1·13), low caregiver educational status (OR 4·19, 95% CI 1·37-10·88), orphanhood (OR 3·57, 95% CI 1·13-9·25), efavirenz-based ART regimens (OR 3·65, 95% CI 1·05-10·69) and female gender (OR 3·15, 95% CI 1·03-7·68) were associated with lower adherence. The rise in CD4 count after ART initiation was more marked in the high adherence group, with the difference in the two groups becoming statistically significant after 6 months of ART (median CD4 count 698 vs 355, p=0·016).

CONCLUSIONS

It is possible to achieve high adherence to ART in a resource-limited setting. Caregiver recall is a reliable and inexpensive tool for measuring adherence. Paediatric adherence to ART is influenced by numerous factors and larger studies are needed to address the issue in India.

Role of non-nucleoside reverse transcriptase inhibitors in treating HIV-infected children

The first-generation non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz and nevirapine, fulfil key roles in antiretroviral therapy for HIV-infected paediatric patients, from lowering the incidence of mother-to-child transmission during pregnancy and birth to treatment throughout childhood and adolescence. Both agents have established efficacy, safety and tolerability profiles, and also offer advantages over other classes of therapy in terms of regimen simplicity and availability across different treatment settings. Although the role of NNRTIs in paediatric treatment strategies is largely determined by experience in adult patients, results of the recent phase II/III PENPACT-1 trial in infants and children aged between 30 days and 18 years have shown that there are no significant differences in 4-year virological, immunological or clinical outcomes between NNRTIs and protease inhibitors as first- and second-line agents. However, results from the IMPAACT P1060 study (cohort 2), conducted in resource-limited settings, showed that infants under 36 months unexposed to NNRTIs were significantly more likely to fail treatment when started on a nevirapine-based regimen than those on a lopinavir/ritonavir-based regimen. Unfortunately, the use of efavirenz and nevirapine in children can be limited by rapid development of high-level resistance to one or both agents, which may reduce the availability of viable treatment options, particularly in resource-limited settings. Several therapeutic strategies addressing this issue are currently under investigation, but a significant need for new NNRTI-based treatment options remains. The more recently approved NNRTI, etravirine, has demonstrated efficacy and safety benefits in HIV-1-infected, NNRTI-resistant adult patients, with a higher genetic barrier to the development of resistance relative to the first-generation NNRTIs. Another NNRTI, rilpivirine (TMC278), is approved for use in HIV-1-infected, treatment-naïve adult patients and has demonstrated an improved tolerability profile compared with efavirenz. Although available data on etravirine in children are currently limited, ongoing trials will provide important information on the potential for their use in novel paediatric treatment strategies. This review examines the role of efavirenz and nevirapine in paediatric antiretroviral therapy in children within different treatment settings. In addition, this review also outlines available clinical data on etravirine and rilpivirine in the context of how these antiretrovirals may address some of the limitations of efavirenz and nevirapine in paediatric patients.

Immunological failure despite virological suppression in HIV seropositive individuals on antiretroviral therapy

BACKGROUND

Some individuals experience a discordant response during antiretroviral therapy (ART), with a blunted CD4+ cell count response despite low HIV-1 RNA plasma levels.

MATERIALS AND METHODS

CD4 counts and viral load of 251 individuals on ART referred to the center were analysed for immunological failure. The viral load tests of 28 patients revealed a discordant response, characterized by low CD4 counts despite viral suppression (<47 copies in 23, <5000 in 4 patients and <10000 in one patient). Univariate and multiple regression analysis was done to determine factors associated with immunological failure in patients with viral suppression.

RESULTS

Twenty-eight patients developed immunological failure over a duration of 3.7±1.14 years despite viral suppression. In univariate analysis of discordant patients, low CD4 counts(<100cells/μl) at start of ART(P=0.0261), less than 50% gain in CD4 count (P=0.048) after one year of start of ART and duration on ART for more than 3 years (P=0.0436) were associated with immunological failure. In multiple regression, duration on ART, age and nadir CD4 count (lowest ever) on treatment were predictors of immunological failure in these patients. Overall females (n=8) demonstrated much higher CD4 counts of 136±72 than males (n=20) 79±38 cells/μl at the time of diagnosis of immunological failure.

CONCLUSIONS

Discordance was observed in 13.59% of patients. Detection of failure to first line therapy based on immunologic criteria, without viral load testing, can result in unnecessary switches to 2(nd) line therapy.

HIV-1 drug resistance genotypic profiles in children with undetectable plasma viremia during antiretroviral therapy

Treatment of HIV-1 infection with highly active antiretroviral therapy has led to sustained viral suppression in the plasma in a large number of children. However, studies have suggested that the integrated provirus in resting CD4+ T lymphocytes could be a source of reactivatable virus and maintain drug-resistant virus. We evaluated the resistance-related mutations in children receiving antiretroviral therapy with prolonged viral suppression. Thirty-two peripheral blood mononuclear cell samples from 16 children with viral loads that had been below detection limits for at least 12 months were obtained at two different time points and the DNAs sequenced. The median CD4 cell count was 1,016 cells/mm³ (347-2,588) and 938 cells/mm³ (440-3,038) at the first and second time points, respectively. The median follow-up time was 15 months (9-27). Six (37.5%) and seven (43.75%) of the 16 patients showed at least one NRTI-associated mutation in the first and second samples, respectively. Two out of 16 (12.5%) had an NNRTI-associated mutation at the first time point and three out of 16 (18.75%) at the second. In addition, 14 out of 16 (87.5%) had at least one PI-associated mutation at both time points. Despite plasma HIV-1 RNA suppression for at least 12 months, resistance-related mutations from previous antiretroviral failures could still be detected in archival virus. Furthermore, viral evolution occurred at the reverse transcriptase region in spite of viral suppression to levels below 400 copies/mL. Persistence of archival resistant virus may be relevant when considering future treatment options.

Immunovirological response to combined antiretroviral therapy and drug resistance patterns in children: 1- and 2-year outcomes in rural Uganda

Background

Children living with HIV continue to be in urgent need of combined antiretroviral therapy (ART). Strategies to scale up and improve pediatric HIV care in resource-poor regions, especially in sub-Saharan Africa, require further research from these settings. We describe treatment outcomes in children treated in rural Uganda after 1 and 2 years of ART start.

Methods

Cross-sectional assessment of all children treated with ART for 12 (M12) and 24 (M24) months was performed. CD4 counts, HIV RNA levels, antiretroviral resistance patterns, and non-nucleoside reverse transcriptase inhibitor (NNRTI) plasma concentrations were determined. Patient adherence and antiretroviral-related toxicity were assessed.

Results

Cohort probabilities of retention in care were 0.86 at both M12 and M24. At survey, 71 (83%, M12) and 32 (78%, M24) children remained on therapy, and 84% participated in the survey. At ART start, 39 (45%) were female; median age was 5 years. Median initial CD4 percent was 11% [IQR 9-15] in children < 5 years old (n = 12); CD4 count was 151 cells/mm³ [IQR 38-188] in those ≥ 5 years old (n = 26). At M12, median CD4 gains were 11% [IQR 10-14] in patients < 5 years old, and 206 cells/mm³ [IQR 98-348] in ≥ 5 years old. At M24, median CD4 gains were 11% [IQR 5-17] and 132 cells/mm³ [IQR 87-443], respectively. Viral suppression (< 400 copies/mL) was achieved in 59% (M12) and 33% (M24) of children. Antiretroviral resistance was found in 25% (M12) and 62% (M24) of children. Overall, 29% of patients had subtherapeutic NNRTI plasma concentrations.

Conclusions

After one year of therapy, satisfactory survival and immunological responses were observed, but nearly 1 in 4 children developed viral resistance and/or subtherapeutic plasma antiretroviral drug levels. Regular weight-adjustment dosing and strategies to reinforce and maintain ART adherence are essential to maximize duration of first-line therapy in children in resource-limited countries.

Induction maintenance concept for HAART as initial treatment in HIV infected infants

Background

Early initiated antiretroviral therapy (ART) in HIV infected infants leads to improved long-term viral suppression and survival. Guidelines recommend initiating therapy with a triple ART consisting of two nucleoside reverse transcriptase inhibitors (NRTIs) and either one additional non-nucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI). Compared to older children and adults, viral relapse is seen more frequently in infants receiving triple ART. We now address the possibility of a more potent ART with a quadruple induction and triple maintenance therapy.

Methods

We examine the longitudinal course in four HIV infected infants, who were referred from other centers and could not be recruited to multicentre trials. We introduced ART initially consisting of two NRTIs, one NNRTI and one PI and later discontinued the PI at the age of 12 months maintaining a triple regime consisting of two NRTIs and one NNRTI.

Results

Provided that therapy adherence was maintained we observed an effective sustained decline of viral load and significant CD4 cell reconstitution even after switching to a triple regime. No drug associated toxicity was seen.

Conclusion

We suggest that a four drug therapy might be a possible initial therapy option in HIV infected infants, at least in those with a high viral load, followed by a maintenance triple regime after 12 months of therapy.

Steady-state pharmacokinetics of tenofovir-based regimens in HIV-infected pediatric patients

HIV-infected children are treated with tenofovir in combination with other, potentially interacting, antiretroviral agents. We report the pharmacokinetic parameters of tenofovir in combination with efavirenz, darunavir-ritonavir, or atazanavir-ritonavir in HIV-infected children. HIV-infected patients 8 to 18 years of age receiving a tenofovir (300 mg)-based regimen containing efavirenz (300 or 600 mg) once daily (group 1), darunavir (300 or 600 mg)-ritonavir (100 mg) twice daily (group 2), or atazanavir (150 to 400 mg)-ritonavir (100 mg) once daily (group 3) were enrolled. Plasma samples were collected over a 24-h time interval. The 90% confidence intervals (90% CI) of the geometric means for the area under the plasma concentration-time curve (AUC) and the minimum concentration of drug in serum (C(min)) of each antiretroviral were computed and checked for overlap with intervals bracketing published values obtained in adult or pediatric studies demonstrating safety and/or efficacy. Group 1 efavirenz plasma concentrations were observed to be higher in patients receiving fixed-dose combination tablets compared with subjects receiving the individual formulation. In group 2, tenofovir and darunavir exposure was observed to be lower than expected. In group 3, tenofovir and atazanavir administered concomitantly produced exposures similar to those published for adult patients. The 90% CI of AUC and C(min) for tenofovir overlapped the target range for all combinations. Informal comparisons of treatment groups did not indicate any advantage to any combination with respect to tenofovir exposure. Further study of exposures achieved with antiretrovirals administered in combination is warranted.

HIV-infected children in rural Zambia achieve good immunologic and virologic outcomes two years after initiating antiretroviral therapy

Background

Many HIV-infected children in sub-Saharan Africa reside in rural areas, yet most research on treatment outcomes has been conducted in urban centers. Rural clinics and residents may face unique barriers to care and treatment.

Methods

A prospective cohort study of HIV-infected children was conducted between September 2007 and September 2010 at the rural HIV clinic in Macha, Zambia. HIV-infected children younger than 16 years of age at study enrollment who received antiretroviral therapy (ART) during the study were eligible. Treatment outcomes during the first two years of ART, including mortality, immunologic status, and virologic suppression, were assessed and risk factors for mortality and virologic suppression were evaluated.

Results

A total of 69 children entered the study receiving ART and 198 initiated ART after study enrollment. The cumulative probabilities of death among children starting ART after study enrollment were 9.0% and 14.4% at 6 and 24 months after ART initiation. Younger age, higher viral load, lower CD4+ T-cell percentage and lower weight-for-age z-scores at ART initiation were associated with higher risk of mortality. The mean CD4⁺ T-cell percentage increased from 16.3% at treatment initiation to 29.3% and 35.0% at 6 and 24 months. The proportion of children with undetectable viral load increased to 88.5% and 77.8% at 6 and 24 months. Children with longer travel times (≥5 hours) and those taking nevirapine at ART initiation, as well as children who were non-adherent, were less likely to achieve virologic suppression after 6 months of ART.

Conclusions

HIV-infected children receiving treatment in a rural clinic experienced sustained immunologic and virologic improvements. Children with longer travel times were less likely to achieve virologic suppression, supporting the need for decentralized models of ART delivery.

Post-HAART outcomes in pediatric populations: comparison of resource-limited and developed countries

CONTEXT

No formal comparison has been made between the pediatric post-highly active antiretroviral therapy (HAART) outcomes of resource-limited and developed countries.

OBJECTIVE

To systematically quantify and compare major baseline characteristics and clinical end points after HAART between resource-limited and developed settings.

METHODS

Published articles and abstracts (International AIDS Society 2009, Conference on Retroviruses and Opportunistic Infections 2010) were examined from inception (first available publication for each search engine) to March 2010. Publications that contained data on post-HAART mortality, weight-for-age z score (WAZ), CD4 count, or viral load (VL) changes in pediatric populations were reviewed. Selected studies met the following criteria: (1) patients were younger than 21 years; (2) HAART was given (≥ 3 antiretroviral medications); and (3) there were >20 patients. Data were extracted for baseline age, CD4 count, VL, WAZ, and mortality, CD4 and virologic suppression over time. Studies were categorized as having been performed in a resource-limited country (RLC) or developed country (DC) on the basis of the United Nations designation. Mean percentage of deaths per cohort and deaths per 100 child-years, baseline CD4 count, VL, WAZ, and age were calculated for RLCs and DCs and compared by using independent samples t tests.

RESULTS

Forty RLC and 28 DC publications were selected (N = 17 875 RLCs; N = 1835 DC). Mean percentage of deaths per cohort and mean deaths per 100 child-years after HAART were significantly higher in RLCs than DCs (7.6 vs 1.6, P < .001, and 8.0 vs 0.9, P < .001, respectively). Mean baseline CD4% was 12% in RLCs and 23% in DCs (P = .01). Mean baseline VLs were 5.5 vs 4.7 log(10) copies per mL in RLCs versus DCs (P < .001).

CONCLUSIONS

Baseline CD4% and VL differ markedly between DCs and RLCs, as does mortality after pediatric HAART. Earlier diagnosis and treatment of pediatric HIV in RLCs would be expected to result in better HAART outcomes.

Enhanced oxidative stress and increased mitochondrial mass during efavirenz-induced apoptosis in human hepatic cells

BACKGROUND AND PURPOSE

Efavirenz (EFV) is widely used in the treatment of HIV-1 infection. Though highly efficient, there is growing concern about EFV-related side effects, the molecular basis of which remains elusive.

EXPERIMENTAL APPROACH

In vitro studies were performed to address the effect of clinically relevant concentrations of EFV (10, 25 and 50 microM) on human hepatic cells.

KEY RESULTS

Cellular proliferation and viability were reduced in a concentration-dependent manner. Analyses of the cell cycle and several cell death parameters (chromatin condensation, phosphatidylserine exteriorization, mitochondrial proapoptotic protein translocation and caspase activation) revealed that EFV triggered apoptosis via the intrinsic pathway. In addition, EFV directly affected mitochondrial function in a reversible manner, inducing a decrease in mitochondrial membrane potential and an increase in mitochondrial superoxide production, followed by a reduction in cellular glutathione content. The rapidity of these actions rules out any involvement of mitochondrial DNA replication, which, until now, was thought to be the main mechanism of mitochondrial toxicity of antiretroviral drugs. Importantly, we also observed an increase in mitochondrial mass, manifested as an elevated cardiolipin content and enhanced expression of mitochondrial proteins, which was not paralleled by an increase in the mtDNA/nuclear DNA copy number ratio. The toxic effect of EFV was partially reversed by antioxidant pretreatment, which suggests ROS generation is involved in this effect.

CONCLUSION AND IMPLICATIONS

Clinically relevant concentrations of EFV were shown to be mitotoxic in human hepatic cells in vitro, which may be pertinent to the understanding of the hepatotoxicity associated with this drug.

Predicting virologic failure among HIV-1-infected children receiving antiretroviral therapy in Tanzania: a cross-sectional study

BACKGROUND

Many HIV care and treatment programs in resource-limited settings rely on clinical and immunologic monitoring of antiretroviral therapy (ART), but accuracy of this strategy to detect virologic failure (VF) among children has not been evaluated.

METHODS

A cross-sectional sample of HIV-infected children aged 1-16 years on ART >or=6 months receiving care at a Tanzanian referral center underwent clinical staging, CD4 lymphocyte measurement, plasma HIV-1 RNA level, and complete blood count. Associations with VF (HIV-1 RNA >or=400 copies/mL) were determined utilizing bivariable and multivariate analyses; accuracy of current clinical and immunologic guidelines in identifying children with VF was assessed.

FINDINGS

Of 206 children (median age 8.7 years, ART duration 2.4 years), 65 (31.6%) demonstrated VF at enrollment. Clinical and immunological criteria identified 2 (3.5%) of 57 children with VF on first-line therapy, exhibiting 3.5% sensitivity and 100% specificity. VF was associated with younger age, receipt of nevirapine vs. efavirenz-based regimen, CD4% < 25%, and physician documentation of maladherence (P < 0.05 on bivariable analysis); the latter 2 factors remained significant on multivariate logistic regression.

INTERPRETATION

This study demonstrates poor performance of clinical and immunologic criteria in identifying children with virologic failure. Affordable techniques for measuring HIV-1 RNA level applicable in resource-limited settings are urgently needed.

Inhibition of mitochondrial function by efavirenz increases lipid content in hepatic cells

Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) widely used in human immunodeficiency virus (HIV) infection therapy. It has been associated with hepatotoxic effects and alterations in lipid and body fat composition. Given the importance of the liver in lipid regulation, we have evaluated the effects of clinically used concentrations of EFV on the mitochondria and lipid metabolism of human hepatic cells in vitro. Mitochondrial function was rapidly undermined by EFV to an extent that varied with the concentration employed; in particular, respiration and intracellular adenosine triphosphate (ATP) levels were reduced whereas reactive oxygen species (ROS) production increased. Results in isolated mitochondria suggest that the mechanism responsible for these actions was a specific inhibition of complex I of the respiratory chain. The reduction in energy production triggered a compensatory mechanism mediated by the enzyme adenosine monophosphate-activated protein kinase (AMPK), the master switch of cellular bioenergetics. Fluorescence and nuclear magnetic resonance demonstrated a rapid intracellular increase of neutral lipids, usually in the form of droplets. This was prevented by the AMPK inhibitor compound C and by removal of fatty acids from the culture medium. These effects were not reproduced by Nevirapine, another NNRTI. EFV is clinically coadministered with two nucleoside reverse transcriptase inhibitors. Evaluation of one of the most common combination, EFV/Lamivudine/Abacavir, revealed that the effects of EFV on ROS production were enhanced.

CONCLUSION

Clinical concentrations of EFV induce bioenergetic stress in hepatic cells by acutely inhibiting mitochondrial function. This new mechanism of mitochondrial interference leads to an accumulation of lipids in the cytoplasm that is mediated by activation of AMPK.

Efavirenz plasma concentrations at 1, 3, and 6 months post-antiretroviral therapy initiation in HIV type 1-infected South African children

The aim of this study was to quantify the plasma efavirenz concentrations over 6 months in black HIV-1-infected South African children (3-14 years), from resource-limited households, attending an outpatient clinic. The children were antiretroviral treatment (ART) naive and received efavirenz in combination with two nucleoside reverse transcriptase inhibitors according to South African national guidelines. Two blood samples were taken between 12 and 20 h after the last efavirenz dose at 1 (n = 58), 3 (n = 54), and 6 (n = 54) months post-ART initiation. A total of 328 efavirenz mid-dose plasma samples from 58 patients was determined with a validated liquid chromatography tandem mass spectrometry method. Viral suppression (<25 copies/ml) was achieved in 95% of the children after 6 months on ART. The median (range) plasma concentration at time points 1 and 2 were 2.06 (0.10-11.14) and 1.80 (0.14-10.70) microg/ml with respective mean (+/-SD) blood sampling times of 15.24 (2.03) and 16.91 (2.03) h post-evening dose. Efavirenz plasma samples within the therapeutic range of 1-4 microg/ml accounted for 58%; 17% were <1 microg/ml and 25% were >4 microg/ml over the 6 months. Efavirenz levels persistently >4 microg/ml were recorded for 13 (23%) children and 3 (5%) children had persistent efavirenz levels <1 microg/ml. Possible reasons for efavirenz plasma levels outside the accepted therapeutic range include genetic variation in drug metabolism, incorrect dosing, drug-drug interactions, and nonadherence. However, these need to be further explored and the importance of sequential plasma levels has been highlighted in this study.

Initial response to protease-inhibitor-based antiretroviral therapy among children less than 2 years of age in South Africa: effect of cotreatment for tuberculosis

BACKGROUND

South African guidelines recommend protease-inhibitor-based antiretroviral therapy (ART) with lopinavir-ritonavir for human immunodeficiency virus (HIV)-infected children <36 months of age. We investigated factors associated with viral suppression and mortality among young children initiating ART.

METHODS

Treatment-naive, ART-eligible, HIV-infected children (aged 6-104 weeks) were enrolled in an ART strategies trial in South Africa and initiated protease-inhibitor-based ART. Mortality and the probability of viral suppression (defined as HIV RNA load of <400 copies/mL) by 39 weeks after ART initiation were investigated.

RESULTS

Of 254 children who initiated ART, 99 (39%) were cotreated for tuberculosis during follow-up. The mortality rate was 14%. Factors predicting mortality were lower pre-ART weight-for-age z score and higher HIV RNA load. By 39 weeks, 84% of surviving children achieved viral suppression. Children who were not cotreated for tuberculosis were more likely to achieve viral suppression (94.8%) than were children who were receiving cotreatment at ART initiation (74.2%) or who started tuberculosis cotreatment after ART initiation (51.6%; P < .001). Other factors predicting lower probability of viral suppression were lower pre-ART weight- and length-for-age z score, higher HIV RNA load, and World Health Organization disease stage.

CONCLUSION

High rates of viral suppression can be achieved among infants and young children who initiate protease-inhibitor-based ART. Cotreatment for tuberculosis reduced viral suppression. How best to treat HIV-infected children who require tuberculosis treatment warrants urgent investigation.

Noninvasive procedures to evaluate liver involvement in HIV-1 vertically infected children

OBJECTIVES

: Progressive liver injury is a concern in HIV-infected children exposed to long-term antiretroviral drugs and to the cytopathic effect of HIV. Yet liver biopsy is usually considered too invasive to be repeated in these patients. The aims of this study are to evaluate the feasibility of noninvasive hepatic investigations in HIV-1-infected children, assess the prevalence of signs of liver affection, and analyse the influence of the HIV disease severity and the exposure to antiretroviral therapy.

MATERIALS AND METHODS

: A cross-sectional study conducted in 26 HIV-1 vertically infected children ages 8 to 18 years old. Liver function was assessed with standard serum biochemical markers, FibroTest, ActiTest, SteatoTest, Forns index, aspartate aminotransferase to platelet ratio index, ultrasound, and Fibroscan.

RESULTS

: Nineteen (>60%) children had signs of liver affection on at least 1 of the test results: 13 (50%) had elevated liver enzymes, 15 (63%), 8 (33%), 5 (21%), and 5 (21%) had abnormal FibroTest, ActiTest, Forns index, and aspartate aminotransferase to platelet ratio index results, respectively. Four children (17%) had mild liver steatosis on ultrasound. Fibroscan measures were significantly higher in patients than in age-matched healthy children. Patients with elevated Fibroscan measures also had significantly higher FibroTest results. Age, HIV stage N in the Centers for Disease Control and Prevention classification and exposure duration to nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor drugs were the main risk factors for hepatotoxicity.

CONCLUSIONS

: More than half of our population of HIV-infected children had biological and/or radiological signs of liver affection. Regular follow-up of liver function is necessary in these patients, which is now possible with noninvasive procedures.

Antiretroviral therapy adherence, virologic and immunologic outcomes in adolescents compared with adults in southern Africa

OBJECTIVE

To determine adherence to and effectiveness of antiretroviral therapy (ART) in adolescents vs. adults in southern Africa.

DESIGN

Observational cohort study.

SETTING

Aid for AIDS, a private sector disease management program in southern Africa.

SUBJECTS

Adolescents (age 11-19 years; n = 154) and adults (n = 7622) initiating ART between 1999 and 2006 and having a viral load measurement within 1 year after ART initiation.

MAIN OUTCOME MEASURES

Primary: virologic suppression (HIV viral load < or = 400 copies/mL), viral rebound, and CD4 T-cell count at 6, 12, 18, and 24 months after ART initiation. Secondary: adherence assessed by pharmacy refills at 6, 12, and 24 months. Multivariate analyses: loglinear regression and Cox proportional hazards.

RESULTS

A significantly smaller proportion of adolescents achieved 100% adherence at each time point (adolescents: 20.7% at 6 months, 14.3% at 12 months, and 6.6% at 24 months; adults: 40.5%, 27.9%, and 20.6% at each time point, respectively; P < 0.01). Patients achieving 100% 12-month adherence were significantly more likely to exhibit virologic suppression at 12 months, regardless of age. However, adolescents achieving virologic suppression had significantly shorter time to viral rebound (adjusted hazard ratio 2.03; 95% confidence interval: 1.31 to 3.13; P < 0.003). Adolescents were less likely to experience long-term immunologic recovery despite initial CD4 T-cell counts comparable to adults.

CONCLUSIONS

Compared with adults, adolescents in southern Africa are less adherent to ART and have lower rates of virologic suppression and immunologic recovery and a higher rate of virologic rebound after initial suppression. Studies must determine specific barriers to adherence in this population and develop appropriate interventions.

Is the recommended dose of efavirenz optimal in young West African human immunodeficiency virus-infected children?

We aimed in this study to describe efavirenz concentration-time courses in treatment-naïve children after once-daily administration to study the effects of age and body weight on efavirenz pharmacokinetics and to test relationships between doses, plasma concentrations, and efficacy. For this purpose, efavirenz concentrations in 48 children were measured after 2 weeks of didanosine-lamivudine-efavirenz treatment, and samples were available for 9/48 children between months 2 and 5 of treatment. Efavirenz concentrations in 200 plasma specimens were measured using a validated high-performance liquid chromatography method. A population pharmacokinetic model was developed with NONMEM. The influence of individual characteristics was tested using a likelihood ratio test. The estimated minimal and maximal concentrations of efavirenz in plasma (Cmin and Cmax, respectively) and the area under the concentration-time curve (AUC) were correlated to the decrease in human immunodeficiency virus type 1 RNA levels after 3 months of treatment. The threshold Cmin (and AUC) that improved efficacy was determined. The target minimal concentration of 4 mg/liter was considered for toxicity. An optimized dosing schedule that would place the highest percentage of children in the interval of effective and nontoxic concentrations was simulated. The pharmacokinetics of efavirenz was best described by a one-compartment model with first-order absorption and elimination. The mean apparent clearance and volume of distribution for efavirenz were 0.211 liter/h/kg and 4.48 liters/kg, respectively. Clearance decreased significantly with age. When the recommended doses were given to 46 of the 48 children, 19% (44% of children weighing less than 15 kg) had C(min)s below 1 mg/liter. A significantly higher percentage of children with C(min)s of >1.1 mg/liter or AUCs of >51 mg/liter x h than of children with lower values had viral load decreases greater than 2 log10 copies/ml after 3 months of treatment. Therefore, to optimize the percentage of children with C(min)s between 1.1 and 4 mg/liter, children should receive the following once-daily efavirenz doses: 25 mg/kg of body weight from 2 to 6 years, 15 mg/kg from 6 to 10 years, and 10 mg/kg from 10 to 15 years. These assumptions should be prospectively confirmed.

Long-term effectiveness of highly active antiretroviral therapy (HAART) in perinatally HIV-infected children in Denmark

The long-term impact of highly active antiretroviral therapy (HAART) on HIV-1 infected children is not well known. The Danish Paediatric HIV Cohort Study includes all patients <16 y of age with HIV-1 infection in Denmark. We report the complete follow-up from 1996 to 2005 of 49 perinatally infected children treated with HAART. Initial HAART included 2 nucleoside reverse-transcriptase inhibitors in combination with either a protease inhibitor (n =38) or a non-nucleoside reverse-transcriptase inhibitor (n =12). 19 (39%) patients were previously treated with mono- or dual therapy. Baseline characteristics were median CD4 percentage 14% and HIV-RNA viral load 4.9 log(10). Within the first 12 weeks of therapy approximately 60% achieved HIV-RNA viral load <500 copies/ml, and this remained stable for up to 8 y, although many children changed the components of HAART. The proportion of children with CD4 percentage >25% increased to 60-70% over the y of treatment. For the total cohort, 245 patient-y of observation were available with only 1 death. During our observation period there were no signs of a waning impact. The challenge remains to maintain a high adherence to therapy as the children grow into adolescence and develop more independence from family and health care staff.

Pharmacotherapy of pediatric and adolescent HIV infection

Significant advances have been made in the treatment of human immunodeficiency virus (HIV) infection over the past two decades. Improved therapy has prolonged survival and improved clinical outcome for HIV-infected children and adults. Sixteen antiretroviral (ART) medications have been approved for use in pediatric HIV infection. The Department of Health and Human Services (DHHS) has issued "Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection", which provide detailed information on currently recommended antiretroviral therapies (ART). However, consultation with an HIV specialist is recommended as the current therapy of pediatric HIV therapy is complex and rapidly evolving.

Steady-state pharmacokinetics of lopinavir/ritonavir in combination with efavirenz in human immunodeficiency virus-infected pediatric patients

The pharmacokinetics of lopinavir/ritonavir (LPV/RTV) 300 mg/m twice daily and efavirenz (EFV) 350 mg/m once daily were evaluated in HIV-infected children. The minimum concentrations for LPV contained values above the target range, and the estimated minimum concentrations for EFV contained values below the range. Our data support the current LPV/RTV dose, but EFV 350 mg/m may not be sufficient.

Adherence to highly active antiretroviral therapy and its correlates among HIV infected pediatric patients in Ethiopia

Background

The introduction of combination antiretroviral therapy (ART) has resulted in striking reductions in HIV-related mortality. Despite increased availability of ART, children remain a neglected population. This may be due to concerns that failure to adhere appears to be related to continued viral replication, treatment failure and the emergence of drug-resistant strains of HIV. This study determines the rates and factors associated with adherence to Antiretroviral (ARV) Drug therapy in HIV-infected children who were receiving Highly Active Antiretroviral Therapy (HAART) in Addis Ababa, Ethiopia in 2008.

Methods

A cross-sectional study was conducted in five hospitals in Addis Ababa from February 18 – April 28, 2008. The study population entailed parents/caretaker and index children who were following ART in the health facilities. A structured questionnaire was used for data collection.

Results

A total of 390 children respondents were included in the study with a response rate of 91%. The majority, equaling 205 (52.6%) of the children, were greater than 9 years of age. Fifty five percent of the children were girls. A total of 339 children (86.9%) as reported by caregivers were adherent to antiretroviral drugs for the past 7 days before the interview. Numerous variables were found to be significantly associated with adherence: children whose parents did not pay a fee for treatment [OR = 0.39 (95%CI: 0.16, 0.92)], children who had ever received any nutritional support from the clinic [OR = 0.34 (95%CI: 0.14, 0.79)] were less likely to adhere. Whereas children who took co-trimoxazole medication/syrup besides ARVs [OR = 3.65 (95%CI: 1.24, 10.74)], children who did not know their sero-status [OR = 2.53 (95%CI: 1.24, 5.19)] and children who were not aware of their caregiver's health problem [OR = 2.45 (95%CI: 1.25, 4.81)] were more likely to adhere than their counterparts.

Conclusion

Adherence to HAART in children in Addis Ababa was higher than other similar setups. However, there are still significant numbers of children who are non-adherent to HAART.

Current and future antiretroviral treatment options in paediatric HIV infection

Because of a lack of prevention policies or problems in implementing prevention of mother-to-child transmission (P-MTCT), most of the 1500 daily new HIV infections in children aged<15 years are caused by MTCT. Fifteen percent of all HIV-infected individuals are children, but the vast majority lack access to highly active antiretroviral therapy (HAART), which can drastically reduce morbidity and mortality. There are 22 antiretroviral drugs currently approved by the US FDA for use in the treatment of HIV-infected adults and adolescents, but only 12 of these drugs are approved for use in children. Antiretroviral drugs belong to four major classes: nucleoside and nucleotide analogue reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors and fusion inhibitors. According to international guidelines developed by organizations including WHO, the Paediatric European Network for Treatment of AIDS (PENTA) and the US National Institutes of Health (US-NIH), the treatment of choice for HIV-infected children and adults is a combination of two NRTIs (backbone treatment) plus a third potent agent from a different class, either an NNRTI or a ritonavir-boosted protease inhibitor. There are specific challenges in treating HIV-infected children, including uncertainty about the best time to start treatment, the need for more paediatric formulations, the lack of pharmacokinetic studies for new drugs, and incomplete dosing guidelines. Furthermore, the most appropriate regimen for an individual child depends on a variety of factors, including the age of the child; the availability of appropriate drug formulations; the potency, complexity and toxicity of the drug regimen; the home situation; the child and caregiver's ability to adhere to the regimen; and the child's antiretroviral treatment history. In addition, antiretroviral drugs are not licensed for all age groups and the drugs are often not affordable. This review describes NNRTI and protease inhibitors as key components of first- and second-line antiretroviral therapy (ART), focusing on the rationale for choosing an NNRTI- versus protease inhibitor-based regimen based on the results of available phase II and III studies. Some of the new agents available for children as second-line and salvage therapy both on- and off-label are also discussed. The drug regimens described in this review are relevant to clinicians in developed and developing countries. The availability of new, potent compounds with different resistance and toxicity profiles may represent an alternative option to interclass switching and could redefine ART strategy, including the option of first-line NRTI-sparing regimens.

Efavirenz in human breast milk, mothers', and newborns' plasma

BACKGROUND AND METHODS

Highly active antiretroviral therapy with efavirenz (EFV) has been prescribed to HIV-positive pregnant women in Rwanda (HIV status 1 and CD4 cell count > 350 cells/mm) during the last trimester of pregnancy and for 6 months after delivery. The EFV concentrations in maternal plasma, breast milk and in newborns' plasma of 13 women and their children between 6 weeks and 6 months post partum are reported.

RESULTS

Results show a mean EFV plasma concentration of 6.55 mg/L in maternal plasma, 3.51 mg/L in skim milk, and 0.85 mg/L in infant plasma. Significant linear correlations between maternal plasma and skim milk (r = 0.8666, P < 0.0001) and between skim milk and infant plasma (r = 0.6646, P < 0.02) were found, but no significant correlation was observed between maternal and infant plasma concentrations (P > 0.05).

CONCLUSIONS

After 6 months of breast-feeding, no child out of the 13 had been infected with HIV and all had good psychomotor and growth development. Our results suggest that EFV may be an alternative to nevirapine (NVP) during the third trimester of pregnancy and during the breast-feeding period. Further studies on larger groups of newborns will be necessary to get a better understanding of possible prophylactic protection of the newborns by highly active antiretroviral therapy with EFV given to the mothers.