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

Association of Virologic Failure and Nonnucleoside Reverse Transcriptase Inhibitor Resistance Found in Antiretroviral-Naive Children Infected With Human Immunodeficiency Virus and Given Efavirenz-Based Treatment

Among 66 antiretroviral-naive children aged <3 years with human immunodeficiency virus (HIV) or coinfected with HIV and tuberculosis and initiating efavirenz-based antiretroviral therapy (ART), non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance was detected before ART in 5 (7.6%). Virologic failure occurred in 2 of these children; they were last tested at 16 and 24 weeks of ART. Pre-ART NNRTI resistance was not associated with virologic failure.

Establishing Dosing Recommendations for Efavirenz in HIV/TB-Coinfected Children Younger Than 3 Years

BACKGROUND

CYP2B6 516 genotype-directed dosing improves efavirenz (EFV) exposures in HIV-infected children younger than 36 months, but such data are lacking in those with tuberculosis (TB) coinfection.

METHODS

Phase I, 24-week safety and pharmacokinetic (PK) study of EFV in HIV-infected children aged 3 to <36 months, with or without TB. CYP2B6 516 genotype classified children into extensive metabolizers (516 TT/GT) and poor metabolizers [(PMs), 516 TT]. EFV doses were 25%-33% higher in children with HIV/TB coinfection targeting EFV area under the curve (AUC) 35-180 μg × h/mL, with individual dose adjustment as necessary. Safety and virologic evaluations were performed every 4-8 weeks.

RESULTS

Fourteen children from 2 African countries and India with HIV/TB enrolled, with 11 aged 3 to <24 months and 3 aged 24-36 months, 12 extensive metabolizers and 2 PMs. Median (Q1, Q3) EFV AUC was 92.87 (40.95, 160.81) μg × h/mL in 8/9 evaluable children aged 3 to <24 months and 319.05 (172.56, 360.48) μg × h/mL in children aged 24-36 months. AUC targets were met in 6/8 and 2/5 of the younger and older age groups, respectively. EFV clearance was reduced in PM's and older children. Pharmacokinetic modeling predicted adequate EFV concentrations if children younger than 24 months received TB-uninfected dosing. All 9 completing 24 weeks achieved viral suppression. Five/14 discontinued treatment early: 1 neutropenia, 3 nonadherence, and 1 with excessive EFV AUC.

CONCLUSIONS

Genotype-directed dosing safely achieved therapeutic EFV concentrations and virologic suppression in HIV/TB-coinfected children younger than 24 months, but further study is needed to confirm appropriate dosing in those aged 24-36 months. This approach is most important for young children and currently a critical unmet need in TB-endemic countries.

Role of efavirenz plasma concentrations on long-term HIV suppression and immune restoration in HIV-infected children

Background

To access the long term relationship between efavirenz plasma concentrations and evolution of HIV RNA loads and CD4 cell counts in children.

Methods

Retrospective analysis of data from HIV-infected children on first line efavirenz-containing regimen. A population pharmacokinetic-pharmacodynamic (PK-PD) model was developed to describe the evolution of HIV RNA load and CD4 cell count (efficacy outcomes) in relation to efavirenz plasma concentration. Individual CYP2B6 516 G>T genotype data were not available for this analysis. A score (IS_EFV) quantifying the effect of efavirenz concentrations on the long-term HIV replication was calculated from efavirenz concentrations and PD parameters and, a value of IS_EFV below which HIV replication is likely not suppressed was determined. Cox proportional hazards regression models were used to assess the association of the risk of viral replication with IS_EFV, and with efavirenz mid-dose concentration(C₁₂).

Results

At treatment initiation, median (interquartile range, IQR) age was 8 years (5 to 10), body weight 17 kg (14 to 23), HIV RNA load 5.1 log₁₀ copies/mL (4.6 to 5.4), and CD4 cell count 71 cells/mm³. A model of PK-PD viral dynamics assuming that efavirenz decreases the rate of infected host cells adequately described the relationship of interest. After adjusting for age, baseline HIV RNA load and CD4 cell counts an IS_EFV <85% was significantly associated with a higher risk of viral replication (p-value <0.001) while no significant association was observed with C₁₂ <1.0 mg/L.

Conclusion

The IS_EFV score was a good predictor of viral replication in children on efavirenz-based treatment.

Antiretroviral Therapy in HIV-Infected Children With Tuberculosis: A Systematic Review

BACKGROUND

Tuberculosis (TB) is the major cause of mortality in HIV-infected children globally. Current guidelines about the management of antiretroviral therapy in children with TB are based on a limited number of nonrandomized studies involving small numbers of participants. The aim of the study was to systematically retrieve and critically appraise available evidence on the efficacy and safety of different antiretroviral regimens in children with HIV infection who are receiving treatment for active TB.

METHODS

We conducted a systematic review of the literature according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Records were retrieved through March 2016 from Medline, Embase and manual screening of key conference proceedings. Four specific research questions assessing available treatment options were defined.

RESULTS

Although 4 independent searches were conducted (1 for each Population, Intervention, Comparator, Outcomes question), results were elaborated and interpreted together because of significant overlap among the retrieved records. Six observational studies were selected for qualitative synthesis while meta-analysis could not be performed.

CONCLUSION

Evidence for optimal treatment options for HIV/TB coinfected children is limited. As the global community strives to reach the fast-track HIV treatment targets and eliminate childhood TB deaths, it must ensure that coinfected children are included in key treatment studies and expand this neglected but crucial area of research.

Choice of initial antiretroviral drugs and treatment outcomes among HIV-infected patients in sub-Saharan Africa: systematic review and meta-analysis of observational studies

BACKGROUND

The effectiveness of antiretroviral therapy (ART) depends on the choice of regimens during initiation. Most evidences from developed countries indicated that there is difference between efavirenz (EFV) and nevirapine (NVP). However, the evidences are limited in resource poor countries particularly in Africa. Thus, this systematic review and meta-analysis was carried out to summarize reported long-term treatment outcomes among people on first line therapy in sub-Saharan Africa.

METHODS

Observational studies that reported odds ratio, relative risk, hazard ratio, or standardized incidence ratio to compare risk of treatment failure among HIV/AIDS patients who initiated ART with EFV versus NVP were systematically searched. Searches were conducted using the MEDLINE database within PubMed, Google Scholar, HINARI, and Research Gates between 2007 and 2016. Information was extracted using standardized form. Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated using random-effect, generic inverse variance method.

RESULT

A total of 6394 articles were identified, of which, 29 were eligible for review and abstraction in sub-Saharan Africa. Seventeen articles were used for the meta-analysis. Of a total of 121,092 independent study participants, 76,719 (63.36%) were females. Of these, 40,480 (33.43%) initiated with NVP containing regimen. Two studies did not report the median CD4 cell counts at initiation. Patients who have low CD4 cell counts initiated with EFV containing regimen. The pooled effect size indicated that treatment failure was reduced by 15%, 0.85 (95%CI: 0.75-0.98), and non-nucleoside reverse transcriptase inhibitor (NNRTI) switch was reduced by 43%, 0.57 (95%CI: 0.37-0.89).

CONCLUSION

The risk of treatment failure and NNRTI switch were lower in patients who initiated with EFV than NVP-containing regimen. The review suggests that initiation of patients with EFV-containing regimen will reduce treatment failure and NNRTI switch.

Antiretroviral treatment in HIV-infected children who require a rifamycin-containing regimen for tuberculosis

INTRODUCTION

In high prevalence settings, tuberculosis and HIV dual infection and co-treatment is frequent. Rifamycins, especially rifampicin, in combination with isoniazid, ethambutol and pyrazinamide are key components of short-course antituberculosis therapy. Areas covered: We reviewed available data, for which articles were identified by a Pubmed search, on rifamycin-antiretroviral interactions in HIV-infected children. Rifamycins have potent inducing effects on phase I and II drug metabolising enzymes and transporters. Antiretroviral medications are often metabolised by the enzymes induced by rifamycins or may suppress specific enzyme activity leading to drug-drug interactions with rifamycins. These may cause significant alterations in their phamacokinetic and pharmacodynamic properties, and sometimes that of the rifamycin. Recommended strategies to adapt to these interactions include avoidance and dose adjustment. Expert opinion: Despite the importance and frequency of tuberculosis as an opportunistic disease in HIV-infected children, current data on the management of co-treated children is based on few studies. We need new strategies to rapidly assess the use of rifamycins, new anti-tuberculosis drugs and antiretroviral drugs together as information on safety and dosing of individual drugs becomes available.

Modeling Outcomes of First-Line Antiretroviral Therapy and Rate of CD4 Counts Change among a Cohort of HIV/AIDS Patients in Ethiopia: A Retrospective Cohort Study

Background

Antiretroviral therapy has shown to be effective in reducing morbidity and mortality in patients infected with HIV for the past couples of decades. However, there remains a need to better understand the characteristics of long-term treatment outcomes in resource poor settings. The main aim of this study was to determine and compare the long-term response of patients on nevirapine and efavirenz based first line antiretroviral therapy regimen in Ethiopia.

Methods

Hospital based retrospective cohort study was conducted from January 2009 to December 2013 at University hospital located in Northwest Ethiopia. Human subject research approval for this study was received from University of Gondar Research Ethics Committee and the medical director of the hospital. Cox-proportional hazards model was used to assess the effect of baseline covariates on composite outcome and a semi-parametric mixed effect model was used to investigate CD4 counts response to treatments.

Results

A total of 2386 HIV/AIDS naive patients were included in this study. Nearly one-in-four patients experienced the events, of which death, lost to follow up, treatment substitution and discontinuation of Non-Nucleoside Reverse Transcriptase Inhibitors(NNRTI) accounted: 99 (26.8%), 122 (33.0%), 137 (37.0%) and 12 (3.2%), respectively. The hazard of composite outcome on nevirapine compared with efavirenz was 1.02(95%CI: 0.52-1.99) with p-value = 0.96. Similarly, the hazard of composite outcome on tenofovir and stavudine compared with zidovudine were 1.87 (95%CI: 1.52-2.32), p-value < 0.0001 and 1.72(95% CI: 1.22-2.32), p-value = 0.002, respectively. The rate of CD4 increase in response to treatment was high during the first 10 months and stabilized later.

Conclusions

This study revealed that treatment responses were comparable whether nevirapine or efavirenz was chosen to initiate antiretroviral therapy for HIV/AIDS patients in Ethiopia. There was significant difference on risk of composite outcome between patients who were initiated with Tenofovir containing ART regimen compared with zidovudine after controlling for NNRTI drug combinations.

Tuberculosis: opportunities and challenges for the 90-90-90 targets in HIV-infected children

INTRODUCTION

In 2014 the Joint United Nations Programme on HIV/AIDS defined the ambitious 90-90-90 targets for 2020, in which 90% of people living with HIV must be diagnosed, 90% of those diagnosed should be on sustained therapy and 90% of those on therapy should have an undetectable viral load. Children are considered to be a key focus population for these targets. This review will highlight key components of the epidemiology, prevention and treatment of tuberculosis (TB) in HIV-infected children in the era of increasing access to antiretroviral therapy (ART) and their relation to the 90-90-90 targets.

DISCUSSION

The majority of HIV-infected children live in countries with a high burden of TB. In settings with a high burden of both diseases such as in sub-Saharan Africa, up to 57% of children diagnosed with and treated for TB are HIV-infected. TB results in substantial morbidity and mortality in HIV-infected children, so preventing TB and optimizing its treatment in HIV-infected children will be important to ensuring good long-term outcomes. Prevention of TB can be achieved by increasing access to ART to both children and adults, and appropriate provision of isoniazid preventative therapy. Co-treatment of HIV and TB is complicated by drug-drug interactions particularly due to the use of rifampicin; these may compromise virologic outcomes if appropriate corrective actions are not taken. There remain substantial operational challenges, and improved integration of paediatric TB and HIV services, including with antenatal and routine under-five care, is an important priority.

CONCLUSIONS

TB may be an important barrier to achievement of the 90-90-90 targets, but specific attention to TB care in HIV-infected children may provide important opportunities to enhance the care of both TB and HIV in children.

Growth reconstitution following antiretroviral therapy and nutritional supplementation: systematic review and meta-analysis

OBJECTIVE

As antiretroviral therapy (ART) expands for HIV-infected children, it is important to determine its impact on growth. We quantified growth and its determinants following ART in resource-limited (RLS) and developed settings.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched publications reporting growth [weight-for-age (WAZ), height-for-age (HAZ), and weight-for-height (WHZ) z scores] in HIV-infected children following ART through August 2014. Inclusion criteria were as follows: younger than 18 years; ART; at least 20 patients; growth at ART; and post-ART growth. Standardized and overall weighted mean differences were calculated using random-effects models.

RESULTS

A total of 67 articles were eligible (RLS = 54; developed settings = 13). Mean age was 5.8 years, and comparable between settings (P = 0.90). Baseline growth was substantially lower in RLS vs. developed settings (WAZ -2.1 vs. -0.5; HAZ -2.2 vs. -0.9; both P < 0.01). Rate of weight but not height reconstitution during 12 and 24 months was higher in RLS (12-month WAZ change 0.84 vs. 0.17, P < 0.01). Growth deficits persisted in RLS after 2 years ART (P = 0.04). Younger cohort age was associated with greater growth reconstitution. Protease inhibitor and nonnucleoside reverse-transcriptase inhibitor regimens yielded comparable growth. Adjusting for age and setting, cohorts with nutritional supplements had greater growth gains (24-month rate difference: WAZ 0.55, P = 0.03; HAZ 0.60, P = 0.007). Supplement benefits were attenuated after adjusting for baseline cohort growth.

CONCLUSION

RLS children had substantial growth deficits compared with developed settings counterparts at ART; growth shortfalls in RLS persisted despite reconstitution. Earlier age and nutritional supplementation at ART may improve growth outcomes. Scant data on supplementation limit evaluation of impact and underscores need for systematic data collection regarding supplementation in pediatric ART programmes/cohorts.

[Childhood tuberculosis]

Childhood TB is an indication of failing TB control in the community. It allows disease persistence in the population. Mortality and morbidity due to TB is high in children. Moreover, HIV co-infection and multidrug-resistant diseases are as frequent in children as in adults. Infection is more frequent in younger children. Disease risk after primary infection is greatest in infants younger than 2 years. In case of exposure, evidence of infection can be obtained using the tuberculin skin test (TST) or an interferon-gamma assay (IGRA). There is no evidence to support the use of IGRA over TST in young children. TB suspicion should be confirmed whenever possible, using new available tools, particularly in case of pulmonary and lymph node TB. Induced sputum, nasopharyngeal aspiration and fine needle aspiration biopsy provide a rapid and definitive diagnosis of mycobacterial infection in a large proportion of patients. Analysis of paediatric samples revealed higher sensitivity and specificity values of molecular techniques in comparison with the ones originated from adults. Children require higher drugs dosages than adults. Short courses of steroids are associated with TB treatment in case of respiratory distress, bronchoscopic desobstruction is proposed for severe airways involvement and antiretroviral therapy is mandatory in case of HIV infection. Post-exposure prophylaxis in children is a highly effective strategy to reduce the risk of TB disease. The optimal therapy for treatment of latent infection with a presumably multidrug-resistant Mycobacterium tuberculosis strain is currently not known.

The effect of tuberculosis treatment on virologic and immunologic response to combination antiretroviral therapy among South African children

BACKGROUND

Many HIV-infected children are diagnosed with tuberculosis (TB), but the effect of TB treatment on virologic and immunologic response to combination antiretroviral therapy (cART) is not well documented.

METHODS

Secondary analysis of a prospective cohort of cART-naive HIV-infected South African children aged 0-8 years initiating cART to assess the effect of TB treatment at the time of cART initiation on virologic suppression (HIV RNA < 50 copies/mL), virologic rebound (HIV RNA > 1000 copies/mL after suppression), and CD4 cell percent (CD4%) increase during the first 24 months of cART.

RESULTS

Of 199 children (median age 2.1 years), 92 (46%) were receiving TB treatment at cART initiation. Children receiving and not receiving TB treatment at cART initiation had similar median baseline HIV RNA (5.4 vs. 5.6 copies/mL), median time to virologic suppression (6.2 months in each group, adjusted hazard ratio, 1.36, 95% confidence interval: 0.94 to 1.96), and rates of virologic rebound by 24 months (23% vs. 24%, adjusted hazard ratio 1.53, 95% confidence interval: 0.71 to 3.30). Children on TB treatment had significantly lower median CD4% at baseline (15.3% vs. 18.8%, P < 0.01) and during the first 12 months of cART but experienced similar median increases in CD4% at 6 months (9.9% vs. 9.6%), 12 months (14.2% vs. 11.9%), and 24 months of cART (14.5% vs. 14.2%). Exploratory analyses suggest that children receiving lopinavir/ritonavir-based cART and TB treatment may have inferior virologic and immunologic response compared with children receiving efavirenz-based cART.

CONCLUSIONS

Receiving TB treatment at the time of cART initiation did not substantially affect virologic or immunologic response to cART in young children.