Adoption is not associated with immunological and virological outcomes in children with perinatally acquired HIV infection in the Netherlands.

OBJECTIVES: To provide an overview of the demographics, treatment characteristics and long-term outcomes of children with perinatal HIV-1 infection (PHIV) living in the Netherlands (NL) and to specifically investigate whether outcomes differ by children's adoption status. DESIGN: A prospective population-based open cohort including children with PHIV in NL. METHODS: We included children with PHIV who had entered HIV care in NL since 2007, in view of a sharp increase in the number of adopted children with PHIV since that year. We compared the proportion with virologic suppression and CD4+T-cell count over time between the following groups of children with PHIV: adopted and born outside NL, non-adopted born in NL, and non-adopted born outside NL, using generalized estimating equations and linear mixed effects models, respectively. To account for the variation in cohort inclusion, we analyzed data of children exposed to at least one year of antiretroviral therapy (ART). RESULTS: We included 148 children (827.5 person-years of follow-up, 72% adopted, age at start care in NL 2.4 (0.5-5.3)). Under-18 mortality was zero. Over the years, a boosted PI-based regimen was most often prescribed. The use of integrase inhibitors increased since 2015. Non-adopted children born in NL were less likely to achieve virological suppression compared to adopted children (OR 0.66, 95%CI 0.51-0.86, p = 0.001), which disappeared after excluding one child with suspected treatment nonadherence (OR 0.85, 95%CI 0.57-1.25, p = 0.400). CD4+T-cell Z-score trajectories were not significantly different between groups. CONCLUSIONS: Despite considerable and increasing diversity of the population of children with PHIV in NL, geographical origin and adoption status do not seem to pose important challenges in achieving good immunological and virological outcomes.

Restoration of the CD4 T cell compartment after long-term highly active antiretroviral therapy without phenotypical signs of accelerated immunological aging.

It remains uncertain whether full T cell reconstitution can be established in HIV-infected children and adults with long-term sustained virological control by highly active antiretroviral therapy (HAART). In this study, we comprehensively analyzed various phenotypical markers of CD4 T cell recovery. In addition to measuring T cell activation and proliferation markers, CD4 T cell generation and aging of the CD4 T cell compartment were assessed by measuring TCR excision circles and the fraction of CD31-expressing naive CD4 T cells. In all children and in adults with relatively high CD4 T cell counts at start of therapy (>200 cells/microl), total CD4 T cell numbers normalized within 1 year of therapy. After long-term HAART (4.4-9.6 years), naive CD4 T cell counts had normalized in both groups. Although in adults with low baseline CD4 T cell counts (<200 cells/microl) total CD4 T cell numbers normalized eventually after at least 7 years of HAART, naive CD4 T cell counts had still not recovered. TCR excision circle data showed that thymic T cell production contributed to naive T cell recovery at all ages. The fraction of CD31-expressing naive CD4 T cells was found to be normal, suggesting that the CD4 T cell repertoire was diverse after long-term HAART. Hence, under sustained viral suppression during long-term HAART, the T cell compartment has the potential to fully recover by generating new naive T cells both in children and in adults with high baseline CD4 T cells counts. Irrespective of baseline CD4 T cell counts, reconstitution occurred without a significant effect on T cell aging as reflected by markers for replicative history.

Neurocognitive function profile in HIV-infected school-age children.

OBJECTIVES: Evaluation of neurocognitive function of school-age children with HIV. DESIGN: Cross-sectional observational study. METHODS: Twenty-two children (median age 9.46 years) with perinatally acquired HIV infection were administered a global intelligence test and tests from the Amsterdam Neuropsychological Tasks (ANT) program. The relationship between various patient-, disease- and treatment factors and neurocognitive outcome variables was examined. RESULTS: Compared with age-appropriate norms, mean IQ of the HIV-infected children was in the average range. However, the HIV-infected children performed poorer on several neuropsychological tests compared with age-appropriate norms. Executive function (attentional flexibility, visuospatial working memory) and processing speed emerged as the most sensitive cognitive measures in relation to HIV disease. The correlational analyses resulted in only two significant outcomes, showing that higher CD4% at initiation of highly active antiretroviral therapy (HAART) and longer treatment duration were associated with better working memory function and attentional control, respectively. CONCLUSIONS: These exploratory data suggest that subtle neurocognitive impairments may exist in HIV-infected school-age children, in particular characterized by compromised executive function and slowed information processing. Further research with larger sample sizes is needed to confirm these findings.

Correction: Long-Term Changes of Subcutaneous Fat Mass in HIV-Infected Children on Antiretroviral Therapy: A Retrospective Analysis of Longitudinal Data from Two Pediatric HIV-Cohorts.

[This corrects the article DOI: 10.1371/journal.pone.0120927.].

Pharmacokinetics, Short-term Safety and Efficacy of the Approved Once-daily Darunavir/Ritonavir Dosing Regimen in HIV-infected Children.

In this multicenter pharmacokinetic study in HIV-infected children (6-12 years of age), we validated the approved once-daily darunavir/ritonavir dosing recommendations. The geometric mean darunavir area under the plasma concentration-time curve was 63.1 h·mg/L, substantially lower than the mean value observed in adults. However, all trough levels were adequate, and short-term virologic outcome was good. These data support the use of the darunavir/ritonavir once-daily dosing recommendations.

Country of birth does not influence long-term clinical, virologic, and immunological outcome of HIV-infected children living in the Netherlands: a cohort study comparing children born in the Netherlands with children born in Sub-Saharan Africa.

BACKGROUND: Immigrant HIV-infected adults in industrialized countries show a poorer clinical and virologic outcome compared with native patients. We aimed to investigate potential differences in clinical, immunological, and virologic outcome in Dutch HIV-infected children born in the Netherlands (NL) versus born in Sub-Saharan Africa (SSA) in a national cohort analysis. METHODS: We included all HIV-infected children registered between 1996 and 2013. Descriptive statistics, mixed-effects models, and Cox proportional hazard models were used to investigate differences between groups. RESULTS: In total, 319 HIV-infected children were registered. The majority of these children were born in SSA (n = 148, 47%) or NL (n = 113, 36%) and most were black (n = 158, 61%). Children born in NL were diagnosed at a median age of 1.2 years and initiated combination antiretroviral therapy (cART) at a median age of 2.6 years, compared with 3.7 and 5.3 years, respectively, for children born in SSA (HIV diagnosis: P < 0.001; cART initiation: P < 0.001). Despite a lower initial CD4 T-cell Z-score in children born in SSA, their immunological reconstitution was similar to children from NL. Virologic suppression was achieved in the majority of all cART-treated children (NL: 96%, SSA: 94%). There was no difference in the occurrence or timing of virologic failure. CONCLUSIONS: Most immigrant HIV-infected children living in NL were born in SSA. Children born in SSA were diagnosed and initiated cART at an older age than children born in NL. Despite initial differences in CD4 T-cell counts and HIV viral load, the long-term immunological and virologic response to cART was similar in both groups.

Long-Term Changes of Subcutaneous Fat Mass in HIV-Infected Children on Antiretroviral Therapy: A Retrospective Analysis of Longitudinal Data from Two Pediatric HIV-Cohorts.

OBJECTIVE: Longitudinal studies objectively evaluating changes in regional fat distribution of HIV-infected children assessed by whole body dual energy X-ray absorptiometry (DEXA) are scarce, whilst this long-term effect of HIV and antiretroviral therapy (cART) is an important issue in infected children in need for lifelong treatment. METHODS: We assessed regional fat distribution over time, measured with sequential DEXA-scans in HIV-infected children on cART in cohorts from South Africa (SA) and the Netherlands (NL), and in healthy controls (SA). Limb and trunk fat Z-scores were calculated with the lambda-mu-sigma (LMS) method. Multivariable linear regression models with mixed effects were used to investigate the effect of cART compounds on body fat distribution over time. RESULTS: In total, 218 children underwent 445 DEXA assessments with a median follow-up of 3.5 years. Fat mass in all limbs was decreased in HIV-infected children compared to controls (arm fat Z-score: coefficient -0.4813; P = 0.006, leg fat Z-score: coefficient -0.4345; P = 0.013). In the HIV-infected group, stavudine treatment was associated with lower subcutaneous fat mass (arm fat Z-score: coefficient -0.5838; P = 0.001), with an additional cumulative exposure effect (arm fat Z-score: coefficient -0.0867; P = 0.003). CONCLUSIONS: Our study shows that subcutaneous fat loss is still prevalent in HIV-infected children on cART, and is strongly associated with cumulative stavudine exposure. These results underline the need for early detection of subcutaneous fat loss and alternative treatment options for HIV-infected children globally.

Results of 2 years of treatment with protease-inhibitor--containing antiretroviral therapy in dutch children infected with human immunodeficiency virus type 1.

Clinical, virologic, and immunologic responses to treatment that contained either indinavir or nelfinavir (both regimens included zidovudine and lamivudine) were determined in 32 children infected with human immunodeficiency virus type 1 (HIV-1) who participated for >/= 96 weeks in a prospective, open, uncontrolled multicenter trial. The pharmacokinetics of indinavir and of nelfinavir were determined and showed large interindividual differences. After 96 weeks of therapy, 69% and 50% of the patients had an HIV-1 RNA load that was below the HIV assays' detection limits of 500 and 40 copies/mL, respectively. Virologic failure was associated with poor compliance and younger age (independent of baseline virus load and receipt of pretreatment). Relative CD4 cell counts increased significantly in relation to the median of the age-specific reference value, from a median of 44% at baseline to 94% after 96 weeks. In a high percentage of the children, clinical, virologic, and immunologic response rates to combination therapy were optimal during the initial 2 years of therapy.

Pharmacokinetics of nelfinavir in children: influencing factors and dose implications.

OBJECTIVES: The study describes the pharmacokinetics (PK) of the protease inhibitor nelfinavir and its active metabolite M8 in children and evaluates the influence of patient-related factors on nelfinavir plasma levels. METHODS: HIV-1-infected children treated with nelfinavir every 8 h (q8h) were eligible for inclusion in this retrospective study. 0-8 h intensive plasma pharmacokinetics (PK) sampling was performed at steady state. Nelfinavir maximum concentration (Cmax), area under the plasma concentration-time curve in 0-8 h (AUC0-8), trough level at the 8 h time point (C8) and relative apparent oral clearance (CI*F/kg) were calculated. RESULTS: Twenty-four children (median age: 4.5 years, median nelfinavir dose: 28 mg/kg q8h) were included. Nelfinavir PK were highly variable: 10/24 children had an AUC0-8 below the value of 12.5 mg/l x h, which has previously been associated with an increased virological failure rate in children. With children aged < 2 years and a dose of 20 mg/kg q8h, a non-significant trend was observed to more AUC0-8 < 12.5 mg/l x h [odds ratio (OR) (95% CI): 2.44 (0.41-14.7) and 8.7 (0.79-95), respectively]. Nelfinavir C8 correlated strongly with AUC0-8 (r = 0.89, P < 0.001). C8 > 0.69 mg/l predicted an AUC0-8 > 12.5 mg/l x h with 71% sensitivity and 80% specificity. Dose of nelfinavir per body surface area was a better predictor of AUC0-8 than dose per body weight. CONCLUSION: Nelfinavir PK show high interindividual variability in children. Children < 2 years old tend to be at increased risk for low nelfinavir levels. These data show that the nelfinavir dose of 20 mg/kg q8h is inadequate in most children. Also, these data suggest that paediatric dosing of nelfinavir based on body surface area should be considered. Therapeutic drug monitoring (TDM) can detect abnormal plasma levels and is therefore useful in optimizing nelfinavir therapy in HIV-infected children. However, further research is needed to more firmly establish a therapeutic range for nelfinavir in children.

Vascular endothelial growth factor and blood-brain barrier disruption in tuberculous meningitis.

BACKGROUND: Tuberculous meningitis (TBM) is characterized by disruption of the blood-brain barrier (BBB), cerebral edema and increased intracranial pressure (ICP). Vascular endothelial growth factor (VEGF) is a potent vascular permeability factor and a mediator of brain edema. AIMS: To investigate whether in children with TBM disruption of the BBB relates to VEGF production and to assess the effect of corticosteroids on Mycobacterium tuberculosis-induced VEGF production by mononuclear leukocytes. METHODS: Blood and CSF samples were collected from 26 children with stage 2-3 TBM and 20 controls. All patients received antituberculous and adjuvant corticosteroid therapy. Children were evaluated by ICP recording, computerized tomography scanning and outcome assessment at 6 months follow-up. BBB disruption was quantified by cerebrospinal fluid (CSF)-serum albumin ratios. VEGF concentrations were measured by enzyme-linked immunosorbent assay. In vitro human monocytic THP-1 cells were stimulated with M. tuberculosis sonicate or culture supernatant, and VEGF production was measured in the presence or absence of corticosteroids. RESULTS: CSF VEGF concentrations were significantly higher in TBM patients than in the controls and correlated with mononuclear cell counts (r = 0.64; P = 0.001) and CSF-serum albumin ratio (r = 0.49; P = 0.015). CSF VEGF did not significantly correlate with elevated ICP. In vitro induction of VEGF production by M. tuberculosis sonicate or culture supernatant could be completely abrogated by corticosteroid treatment. CONCLUSIONS: Inflammatory cells secrete VEGF during TBM. CSF VEGF correlates with BBB disruption. Inhibition of VEGF may explain part of the clinical effect of adjuvant corticosteroid therapy in TBM.

Long-term effectiveness of combination antiretroviral therapy and prevalence of HIV drug resistance in HIV-1-infected children and adolescents in Rwanda.

OBJECTIVE: To determine the long-term outcomes of treatment and prevalence of genotypic drug resistance in children and adolescents on combination antiretroviral therapy. METHODS: A cross-sectional study (September 2009 to October 2010) in which clinical, immunologic and virologic outcomes were assessed at a single-study visit and through patient records in a cohort of HIV-infected children and adolescents. Risk factors for clinical and immunologic responses and virologic outcome were evaluated using logistic regression, and the accuracy of clinical and immunologic criteria in identifying virologic failure was assessed. RESULTS: Four hundred twenty-four patients were enrolled with a median age of 10.8 years (range: 1.7-18.8) and a median duration on combination antiretroviral therapy of 3.4 years (range: 1.0-8.1). Thirty-three percent were stunted and 17% underweight. Eighty-four percent (95% confidence interval: 79-87) of children >5 years had CD4 ≥350 cells/mm and in 74% (95% confidence interval: 62-84) of younger children CD4% was ≥25. CD4 values and age at combination antiretroviral therapy initiation were independently associated with CD4 outcomes; 124 (29%) had HIV-1 RNA ≥1000 copies/mL, with no significant predictors. Sensitivity for weight-for-age and height-for-age and CD4 cells (<350/mm) remained under 50% (15-42%); CD4 cells showed the best specificity, ranging from 91% to 97%. Of 52 samples tested, ≥1 mutations were observed in 91% (nucleoside reverse transcriptase inhibitors) and 95% (non-nucleoside reverse transcriptase inhibitors); 1 to 2 thymidine analogue-associated mutations were detected in 16 (31%) and ≥3 thymidine analogue-associated mutations in 7 (13%). CONCLUSION: Nearly 1 in 3 children showed virologic failure, and >10% of the subgroup of children with treatment failure in whom genotyping was performed demonstrated multiple HIV drug resistance mutations. Neither clinical condition nor CD4 cells were good indicators for treatment failure.

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/mm3 respectively, 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.

"Let's talk about sex": a qualitative study of Rwandan adolescents' views on sex and HIV.

OBJECTIVE: This qualitative study explored the views and experiences of adolescents with perinatally acquired HIV in Kigali, Rwanda, regarding sex, love, marriage, children and hope for the future. DESIGN: The study enrolled 42 adolescents who had received combination antiretroviral therapy for at least 12 months, and a selection of their primary caregivers. Study methods included 3 multiple day workshops consisting of role-playing and focus group discussions (FGDs) with adolescents, 8 in-depth interviews with adolescents, and one FGD with caregivers. RESULTS: The adolescents reported experiencing similar sexual needs and dilemmas as most other adolescents, but with an added layer of complexity due to fears related to HIV transmission and/or rejection by partners. They desired more advice from their parents/caregivers on these topics. Although they struggled with aspects of sex, love, marriage and having children, most agreed that they would find love, be married and have children in the future. The two most discussed HIV-related anxieties were how and when to disclose to a (potential) sex/marriage partner and whether to have children. However, most adolescents felt that they had a right to love and be loved, and were aware of prevention-of-mother-to-child-transmission (PMTCT) options in Rwanda. Adolescents generally spoke about their future role in society in a positive manner. CONCLUSION: Strengthening the life skills of HIV-positive adolescents, especially around HIV disclosure and reduction of HIV transmission, as well as the support skills of parents/caregivers, may not only reduce onward HIV transmission but also improve quality of life by reducing anxiety.

Hepatitis B virus prevalence and vaccine response in HIV-infected children and adolescents on combination antiretroviral therapy in Kigali, Rwanda.

OBJECTIVE: The aim of this study was to determine the prevalence of hepatitis B virus (HBV) infection in a cohort of HIV-infected Rwandan children and adolescents on combination antiretroviral therapy (cART), and the success rate of HBV vaccination in those children found to be HBV negative. METHODS: HIV-infected children and adolescents (age 8-17 years) receiving cART with CD4 T-cells count ≥200 cells/mm and/or ≥15% and without prior HBV vaccination (by history, vaccination cards and clinic records) underwent serologic testing for past (negative HBV surface antigen [HBsAg] with positive antibody to HBV core antigen [cAb] and to HBsAg [anti-HBs]) or active HBV infection (positive HBsAg). Children with any positive HBV serologic tests were excluded from further vaccination; all others completed 3 HBV immunizations with 10 µg of ENGERIX-B. Anti-HBs titer was measured 4-6 weeks after the last immunization. RESULTS: Of 88 children, 6 (7%) children had active HBV infection and 8 (9%) had past HBV infection. The median (interquartile range) age, CD4 T-cell count and cART duration were 12.3 (10.1-13.9) years, 626 (503 to 942) cells/mm and 1.9 (1.5-2.7) years, respectively. Seventeen children had detectable plasma HIV-1 RNA. Seventy-3 children completed 3 immunizations with median (interquartile range) postimmunization anti-HBs concentration of 151 mIU/mL (1.03-650). Overall, 52 children (71%, 95% confidence interval: 61-82) developed a protective anti-HBs response. HIV-1 RNA and CD4 T-cell count were independent predictors of a protective anti-HBs response. Protective anti-HBs response was achieved in 82% of children with undetectable HIV-1 RNA and 77% with CD4 T cells ≥350/mm. CONCLUSIONS: The substantial HBV prevalence in this cohort suggests that HIV-infected Rwandan children should be screened for HBV before cART initiation. HIV viral suppression and CD4 T cells ≥350/mm favored the likelihood of a protective response after HBV vaccination.

Sustained virological response on second-line antiretroviral therapy following virological failure in HIV-infected patients in rural South Africa.

OBJECTIVE: This study aims to describe the virological, immunological and clinical efficacy of protease inhibitor (PI)-based second-line antiretroviral therapy (ART) in rural South Africa. METHODS: An observational cohort study was performed on 210 patients (including 39 children) who initiated PI-based second-line therapy at least 12 months prior to data collection. Biannual clinical, immunological and virological monitoring was performed. Primary endpoints were adequate virological response (plasma HIV-1 RNA<400 copies/ml), full virological suppression (plasma HIV-1 RNA<50 copies/ml) and treatment failure (virological failure (plasma HIV-1 RNA>1000 after initial virological response) or on-going viremia (plasma HIV-1 RNA never<400 copies/ml for more than six months)). Data were analyzed by an on-treatment (OT) and intention-to-treat (ITT) approach. Analyses were primarily performed on the group of patients who switched following first-line virological failure. RESULTS: Median duration of follow-up after switch to second-line treatment was 20 months [IQR 11-35]. 191 patients had switched to second-line ART due to first-line virological failure. 139/191 of them (72.8%, ITT) were in care and on treatment at the end of follow-up and 11/191 (5.8%, ITT) had died. After twelve months, an adequate virological response was seen in 92/128 patients (71.9%, OT), of which 78/128 (60.9%, OT) experienced full virological suppression. Virological response remained stable after 24 months. Virological efficacy was similar amongst adult and pediatric patients. As in first-line ART, we observed a lack of correlation between virological failure and WHO-defined immunological failure. CONCLUSIONS: Good virological outcomes following first-line failure can be achieved with PI-based, second-line antiretroviral therapy in both adult and pediatric patients in rural South Africa. Retention rates were high and virological outcomes were sustainable during the two-year follow-up period, although persisting low-level viremia occurred in a subset of patients. The observed viro-immunological dissociation emphasizes the need for virological monitoring.

Long-term response to combination antiretroviral therapy in HIV-infected children in the Netherlands registered from 1996 to 2012.

OBJECTIVES: To describe demographic and treatment characteristics of the Dutch vertically HIV-infected paediatric population from 1996 to 2012, and to investigate the long-term virological and immunological response to combination antiretroviral therapy (cART), with emphasis on the influence of age at cART initiation and initial CD4 cell counts. DESIGN: Descriptive cohort study. METHODS: From 1996 to 2012, all paediatric HIV clinics in the Netherlands provided data on their HIV-infected population. Descriptive statistics, parametric and non-parametric comparative tests, and random-effects linear regression models were performed to investigate the different aspects of this cohort. RESULTS: A total of 229 vertically HIV-infected children were included. The majority of all mothers (64%) and almost half of the children (43%) originated from sub-Saharan Africa. Ritonavir-boosted lopinavir and efavirenz have replaced indinavir, nelfinavir and nevirapine as preferred first-line cART regimens. Long-term CD4 T-cell reconstitution (with CD4 cell counts corrected for age) was independent of age and CD4 cell count at cART initiation. The decline in HIV viral load after cART introduction occurred faster over the studied time period. The percentage of children with an undetectable viral load rose substantially from 1996 to 2012. Mortality was 0.3 per 100 person-years. CONCLUSION: A sustained immunological response in the Dutch paediatric HIV-infected population was independent of age as well as CD4 cell count at cART initiation, despite a higher initial HIV viral load in the youngest children. The percentage of children with an undetectable HIV viral load rose substantially over the years and there was a low mortality rate in comparison with reports from other industrialized countries.

Mid-dosing interval efavirenz plasma concentrations in HIV-1-infected children in Rwanda: treatment efficacy, tolerability, adherence, and the influence of CYP2B6 polymorphisms.

This study evaluated mid-dosing interval efavirenz plasma concentrations and the influence of CYP2B6 polymorphisms in relation to efficacy, tolerability, and adherence in 97 Rwandan HIV-infected children (3-16 years). Plasma drug concentrations and CYP2B6 polymorphisms were determined. Ten children were excluded for nonadherence. Large intersubject variability in efavirenz plasma concentrations was found. Of the 87 remaining, efavirenz concentrations were therapeutic, supratherapeutic, and subtherapeutic in 67%, 20%, and 14%, respectively. No associations were found between efavirenz concentrations and central nervous system disturbances or virologic failure. Minor allele frequencies were 0.32 (516G>T), 0.33 (785A>G), and 0.09 (983T>C). Polymorphisms in CYP2B6 were strongly associated with high efavirenz levels.

Ritonavir-enhanced pharmacokinetics of nelfinavir/M8 during rifampin use.

OBJECTIVE: To describe a case of successful protease inhibitor-based highly active antiretroviral therapy (HAART) concomitant with rifampin. CASE SUMMARY: In a 7-month-old male infant with tuberculosis and HIV-1 infection, tuberculosis therapy including rifampin and HAART containing the protease inhibitor nelfinavir 40 mg/kg every 8 hours was started. Intensive steady-state pharmacokinetic sampling from baseline to 8 hours revealed very low plasma concentrations of nelfinavir: area under the plasma concentration-time curve (AUC(0-24)) <10% of adult population values for 750 mg every 8 hours and nonquantifiable concentrations of nelfinavir's principal metabolite (M8). Nelfinavir 40 mg/kg every 8 hours was then substituted with nelfinavir 30 mg/kg twice daily plus ritonavir 400 mg/m(2) twice daily. Intensive steady-state (0-12 h) pharmacokinetic sampling was repeated. Nelfinavir concentrations had improved, but remained low when compared with adult population values of 1250 mg every 12 hours: AUC(0-24) 21.9 versus 47.6 mg/L*h (46%) and 12-hour trough level (C(12)) 0.25 versus 0.85 mg/L (29%). However, concentrations of M8 considerably exceeded population values: AUC(0-24) 57.5 versus 13.6 mg/L*h (443%) and C(12) 1.35 versus 0.28 mg/L (482%). Since M8 concentrations were highly elevated, pharmacokinetic parameters for (nelfinavir + M8) were used rather than those for nelfinavir alone. Thus, AUC(0-24) (nelfinavir + M8) and C(12) (nelfinavir + M8) comprised 130% and 142%, respectively of the adult population values. This, in addition to good clinical response and tolerability, favored continuation of the regimen. CONCLUSIONS: In an infant, nelfinavir-containing HAART was successfully used with rifampin after the addition of ritonavir. Ritonavir resolved the pharmacokinetic interaction between rifampin and nelfinavir by boosting nelfinavir and, especially, M8 concentrations. More research is needed to confirm these results.