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 (ISEFV) quantifying the effect of efavirenz concentrations on the long-term HIV replication was calculated from efavirenz concentrations and PD parameters and, a value of ISEFV 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 ISEFV, 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 ISEFV <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 ISEFV score was a good predictor of viral replication in children on efavirenz-based treatment.

Long-term trends in mortality and AIDS-defining events after combination ART initiation among children and adolescents with perinatal HIV infection in 17 middle- and high-income countries in Europe and Thailand: A cohort study.

BACKGROUND: Published estimates of mortality and progression to AIDS as children with HIV approach adulthood are limited. We describe rates and risk factors for death and AIDS-defining events in children and adolescents after initiation of combination antiretroviral therapy (cART) in 17 middle- and high-income countries, including some in Western and Central Europe (W&CE), Eastern Europe (Russia and Ukraine), and Thailand. METHODS AND FINDINGS: Children with perinatal HIV aged <18 years initiating cART were followed until their 21st birthday, transfer to adult care, death, loss to follow-up, or last visit up until 31 December 2013. Rates of death and first AIDS-defining events were calculated. Baseline and time-updated risk factors for early/late (≤/>6 months of cART) death and progression to AIDS were assessed. Of 3,526 children included, 32% were from the United Kingdom or Ireland, 30% from elsewhere in W&CE, 18% from Russia or Ukraine, and 20% from Thailand. At cART initiation, median age was 5.2 (IQR 1.4-9.3) years; 35% of children aged <5 years had a CD4 lymphocyte percentage <15% in 1997-2003, which fell to 15% of children in 2011 onwards (p < 0.001). Similarly, 53% and 18% of children ≥5 years had a CD4 count <200 cells/mm3 in 1997-2003 and in 2011 onwards, respectively (p < 0.001). Median follow-up was 5.6 (2.9-8.7) years. Of 94 deaths and 237 first AIDS-defining events, 43 (46%) and 100 (42%) were within 6 months of initiating cART, respectively. Multivariable predictors of early death were: being in the first year of life; residence in Russia, Ukraine, or Thailand; AIDS at cART start; initiating cART on a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen; severe immune suppression; and low BMI-for-age z-score. Current severe immune suppression, low current BMI-for-age z-score, and current viral load >400 c/mL predicted late death. Predictors of early and late progression to AIDS were similar. Study limitations include incomplete recording of US Centers for Disease Control (CDC) disease stage B events and serious adverse events in some countries; events that were distributed over a long time period, and that we lacked power to analyse trends in patterns and causes of death over time. CONCLUSIONS: In our study, 3,526 children and adolescents with perinatal HIV infection initiated antiretroviral therapy (ART) in countries in Europe and Thailand. We observed that over 40% of deaths occurred ≤6 months after cART initiation. Greater early mortality risk in infants, as compared to older children, and in Russia, Ukraine, or Thailand as compared to W&CE, raises concern. Current severe immune suppression, being underweight, and unsuppressed viral load were associated with a higher risk of death at >6 months after initiation of cART.

Brief Report: AIDS-Defining Events and Deaths in HIV-Infected Children and Adolescents on Antiretrovirals: A 14-Year Study in Thailand.

BACKGROUND: Data are scarce on the long-term clinical outcomes of perinatally HIV-infected children and adolescents receiving antiretroviral therapy (ART) in low/middle-income countries. We assessed the incidence of mortality before (early) and after (late) 6 months of ART and of the composite outcome of new/recurrent AIDS-defining event or death >6 months after ART start (late AIDS/death) and their associated factors. METHODS: Study population was perinatally HIV-infected children (≤18 years) initiating ART within the Program for HIV Prevention and Treatment observational cohort (NCT00433030). Factors associated with late AIDS/death were assessed using competing risk regression models accounting for lost to-follow-up and included baseline and time-updated variables. RESULTS: Among 619 children, "early" mortality incidence was 99 deaths per 1000 person-years of follow-up [95% confidence interval (CI): 69 to 142] and "late" mortality 6 per 1000 person-years of follow-up (95% CI: 4 to 9). Of the 553 children alive >6 months after ART initiation, median age at ART initiation was 6.4 years, CD4% 8.2%, and HIV-RNA load 5.1 log10 copies/mL. Thirty-eight (7%) children developed late AIDS/death after median time of 3.3 years: 24 died and 24 experienced new/recurrent AIDS-defining events (10 subsequently died). Factors independently associated with late AIDS/death were current age ≥13 years (adjusted subdistribution hazard ratio 4.9; 95% CI: 2.4 to 10.1), HIV-RNA load always ≥400 copies/mL (12.3; 95% CI: 4.0 to 37.6), BMI-z-score always <-2 SD (13.7; 95% CI: 3.4 to 55.7), and hemoglobin <8 g/dL at least once (4.6; 95% CI: 2.0 to 10.5). CONCLUSIONS: After the initial 6 months of ART, being an adolescent, persistent viremia, poor nutritional status, and severe anemia were associated with poor clinical outcomes. This supports the need for novel interventions that target children, particularly adolescents with poor growth and uncontrolled viremia.

Incidence of Tuberculosis and Associated Mortality in a Cohort of Human Immunodeficiency Virus-Infected Children Initiating Antiretroviral Therapy.

BACKGROUND.: We assessed the incidence of tuberculosis, risk factors for tuberculosis, and the contribution of tuberculosis on mortality in a large cohort of human immunodeficiency virus (HIV)-infected children <15 years of age initiating first-line antiretroviral therapy (ART) between 1999 and 2012 in Thailand, one of the 22 high tuberculosis burden countries. METHODS.: A physician reviewed and classified tuberculosis cases. Incidence was the number of children with incident tuberculosis, defined as a first or recurrent tuberculosis diagnosis >30 days after ART initiation, divided by the total person-years of follow-up (PYFU). Risk factors for incident tuberculosis were identified using Fine and Gray's competing risks models, with death from other causes treated as a competing event, and risk factors for death were identified using Cox models. RESULTS.: At ART initiation, 670 children (55% female) had a median age of 6.4 years (interquartile range, 2.0-9.6), body mass index-for-age z-score -0.8 (-1.9 to 0.0), HIV ribonucleic acid viral load 5.1 log10 copies/mL (4.6-5.6), and CD4 9% (3-17). Median duration of follow-up was 7.7 years. Tuberculosis incidence was 7 per 1000 PYFU (95% confidence interval [CI], 5-11) and decreased with ART duration. Lower age-adjusted hemoglobin, hematocrit, and CD4 at ART initiation were associated with a higher risk of incident tuberculosis. Of the 30 incident tuberculosis cases, 9 died. Diagnosis of incident tuberculosis was associated with mortality (unadjusted hazard ratio = 10.2, 95% CI = 4.8-21.5, P < .001 and adjusted hazard ratio = 5.4, 95% CI = 2.5-11.7, P < .001). CONCLUSIONS.: Incident tuberculosis was strongly associated with mortality. CD4 counts or hemoglobin or hematocrit levels may prompt clinicians to consider a possible tuberculosis infection.

Treatment Failure in HIV-Infected Children on Second-line Protease Inhibitor-Based Antiretroviral Therapy.

BACKGROUND: Human immunodeficiency virus (HIV)-infected children failing second-line antiretroviral therapy (ART) have no access to third-line antiretroviral drugs in many resource-limited settings. It is important to identify risk factors for second-line regimen failure. METHODS: HIV-infected children initiating protease inhibitor (PI)-containing second-line ART within the Program for HIV Prevention and Treatment observational cohort study in Thailand between 2002 and 2010 were included. Treatment failure was defined as confirmed HIV type 1 RNA load >400 copies/mL after at least 6 months on second-line regimen or death. Adherence was assessed by drug plasma levels and patient self-report. Cox proportional hazards regression analyses were used to identify risk factors for failure. RESULTS: A total of 111 children started a PI-based second-line regimen, including 59 girls (53%). Median first-line ART duration was 1.9 years (interquartile range [IQR], 1.4-3.3 years), and median age at second-line initiation was 10.7 years (IQR, 6.3-13.4 years). Fifty-four children (49%) experienced virologic failure, and 2 (2%) died. The risk of treatment failure 24 months after second-line initiation was 41%. In multivariate analyses, failure was independently associated with exposure to first-line ART for >2 years (adjusted hazard ratio [aHR], 1.8; P = .03), age >13 years (aHR, 2.9; P < .001), body mass index-for-age z score < -2 standard deviations at second-line initiation (aHR, 2.8; P = .03), and undetectable drug levels within 6 months following second-line initiation (aHR, 4.5; P < .001). CONCLUSIONS: Children with longer exposure to first-line ART, entry to adolescence, underweight, and/or undetectable drug levels were at higher risk of failing second-line ART and thus should be closely monitored.