Search

Rationale: There is accumulating evidence that higher-than-standard doses of isoniazid are effective against low-to-intermediate-level isoniazid-resistant strains of Mycobacterium tuberculosis, but...

Background Dispersible pediatric fixed-dose combination (FDC) tablets delivering higher doses of first-line antituberculosis drugs in World Health Organization–recommended weight bands were introduced in 2015. We report the first pharmacokinetic data for these FDC tablets in Zambian and South African children in the treatment-shortening SHINE trial. Methods Children weighing 4.0–7.9, 8.0–11.9, 12.0–15.9, or 16.0–24.9 kg received 1, 2, 3, or 4 tablets daily, respectively (rifampicin/isoniazid/pyrazinamide [75/50/150 mg], with or without 100 mg ethambutol, or rifampicin/isoniazid [75/50 mg]). Children 25.0–36.9 kg received doses recommended for adults Results In the 77 children evaluated, the median age (interquartile range) was 3.7 (1.4–6.6) years; 40 (52%) were male and 20 (26%) were human immunodeficiency virus positive. The median area under the concentration-time curve from 0 to 24 hours for rifampicin, isoniazid, pyrazinamide, and ethambutol was 32.5 (interquartile range, 20.1–45.1), 16.7 (9.2–25.9), 317 (263–399), and 9.5 (7.5–11.5) mg⋅h/L, respectively, and lower in children than in adults for rifampicin in the 4.0–7.9-, 8–11.9-, and ≥25-kg weight bands, isoniazid in the 4.0–7.9-kg and ≥25-kg weight bands, and ethambutol in all 5 weight bands. Pyrazinamide exposures were similar to those in adults. Conclusions Recommended weight band–based FDC doses result in lower drug exposures in children in lower weight bands and in those ≥25 kg (receiving adult doses). Further adjustments to current doses are needed to match current target exposures in adults. The use of ethambutol at the current World Health Organization–recommended doses requires further evaluation.

BACKGROUND HIV population viral load (PVL) can reflect antiretroviral therapy program effectiveness and transmission potential in a community. Using nationally representative data from household surveys conducted in Zimbabwe, Malawi, and Zambia in 2015-16, we examined the association between various VL measures and the probability of at least one recent HIV-1 infection in the community. METHODS We used limiting-antigen avidity enzyme immunoassay, viral load suppression (VLS) (HIV RNA

Background Pregnancy increases the risk of tuberculosis and its complications. A 3-month regimen of weekly isoniazid and rifapentine (3HP) is safe and effective for tuberculosis prevention in adults and children, including those with HIV, but 3HP has not been evaluated in pregnancy. Methods IMPAACT 2001 was a phase I/II trial evaluating the pharmacokinetics and safety of 3HP among pregnant women with indications for tuberculosis preventative therapy in Haiti, Kenya, Malawi, Thailand, and Zimbabwe (NCT02651259). Isoniazid and rifapentine were provided at standard doses (900 mg/week). Pharmacokinetic sampling was performed with the first (second/third trimester) and twelfth (third trimester/postpartum) doses. Nonlinear mixed-effects models were used to estimate drug population pharmacokinetics. Results Of 50 participants, 20 had HIV and were taking efavirenz-based antiretroviral therapy. Among women without HIV, clearance of rifapentine was 28% lower during pregnancy than postpartum (1.20 vs 1.53 L/hour, P Conclusions 3HP does not require dose adjustment in pregnancy. Rifapentine clearance is higher among women with HIV, but all women achieved exposures of rifapentine and isoniazid associated with successful tuberculosis prevention. The data support proceeding with larger safety-focused studies of 3HP in pregnancy. Clinical Trials Registration ClinicalTrials.gov, NCT02651259.

Background Moxifloxacin is a recommended drug for rifampin-resistant tuberculosis (RR-TB) treatment, but there is limited pediatric pharmacokinetic and safety data, especially in young children. We characterize moxifloxacin population pharmacokinetics and QT interval prolongation and evaluate optimal dosing in children with RR-TB. Methods Pharmacokinetic data were pooled from 2 observational studies in South African children with RR-TB routinely treated with oral moxifloxacin once daily. The population pharmacokinetics and Fridericia-corrected QT (QTcF)-interval prolongation were characterized in NONMEM. Pharmacokinetic simulations were performed to predict expected exposure and optimal weight-banded dosing. Results Eighty-five children contributed pharmacokinetic data (median [range] age of 4.6 [0.8–15] years); 16 (19%) were aged Conclusions Moxifloxacin doses above 10–15 mg/kg are likely required in young children to match adult exposures but require further safety assessment, especially when coadministered with other QT-prolonging agents.

Supplemental Digital Content is Available in the Text., Background: Patients hospitalized with advanced HIV have a high mortality risk. We assessed viremia and drug resistance among differentiated care services and explored whether expediting the switching of failing treatments may be justified. Setting: Hospitals in the Democratic Republic of (DRC) Congo (HIV hospital) and Kenya (general hospital including HIV care). Methods: Viral load (VL) testing and drug resistance (DR) genotyping were conducted for HIV inpatients ≥15 years, on first-line antiretroviral therapy (ART) for ≥6 months, and CD4 ≤350 cells/µL. Dual-class DR was defined as low-, intermediate-, or high-level DR to at least 1 nucleoside reverse transcriptase inhibitor and 1 non-nucleoside reverse transcriptase inhibitor. ART regimens were considered ineffective if dual-class DR was detected at viral failure (VL ≥1000 copies/mL). Results: Among 305 inpatients, 36.7% (Kenya) and 71.2% (DRC) had VL ≥1000 copies/mL, of which 72.9% and 73.7% had dual-class DR. Among viral failures on tenofovir disoproxil fumarate (TDF)-based regimens, 56.1% had TDF-DR and 29.8% zidovudine (AZT)-DR; on AZT regimens, 71.4% had AZT-DR and 61.9% TDF-DR, respectively. Treatment interruptions (≥48 hours during past 6 months) were reported by 41.7% (Kenya) and 56.7% (DRC). Approximately 56.2% (Kenya) and 47.4% (DRC) on TDF regimens had tenofovir diphosphate concentrations

Objective: Recycling tenofovir and lamivudine/emtricitabine (XTC) with dolutegravir would provide a more tolerable, affordable, and scalable second-line regimen than dolutegravir with an optimized nucleoside reverse transcriptase inhibitor (NRTI) backbone. We evaluated efficacy of tenofovir/lamivudine/dolutegravir (TLD) in patients failing first-line tenofovir/XTC/efavirenz or nevirapine. Design: Single arm, prospective, interventional study. Setting: Two primary care clinics in Khayelitsha, South Africa. Participants: Sixty adult patients with two viral loads greater than 1000 copies/ml. Intervention: Participants were switched to TLD with additional dolutegravir (50 mg) for 2 weeks to overcome efavirenz induction. Primary outcome: Proportion achieving viral load less than 50 copies/ml at week 24 using the FDA snapshot algorithm. Results: Baseline median CD4+ cell count was 248 cells/μl, viral load 10 580 copies/ml and 48 of 54 (89%) had resistance (Stanford score ≥15) to one or both of tenofovir and XTC. No participants were lost to follow-up. At week 24, 51 of 60 [85%, 95% confidence interval (CI) 73-93%] were virologically suppressed, six had viral load 50-100 copies/ml, one had viral load 100-1000 copies/ml, one no viral load in window, and one switched because of tenofovir-related adverse event. No integrase mutations were detected in the one participant meeting criteria for resistance testing. Virological suppression was achieved by 29 of 35 (83%, 95% CI 66-93%) with resistance to tenofovir and XTC, 11 of 13 (85%, 95% CI 55-98%) with resistance to XTC, and six of six (100%, 95% CI 54-100%) with resistance to neither. Conclusion: A high proportion of adults switching to second-line TLD achieved virologic suppression despite substantial baseline NRTI resistance and most not suppressed had low-level viraemia (≤100 copies/ml). This suggests recycling tenofovir and XTC with dolutegravir could provide an effective second-line option.

Background Adolescents aged 10–19 years living with human immunodeficiency virus (HIV) (ALHIV), both perinatally infected adolescents (APHIV) and behaviorally infected adolescents (ABHIV), are a growing population with distinct care needs. We characterized the epidemiology of HIV in adolescents included in Population-based HIV Impact Assessments (2015–2017) in Zimbabwe, Malawi, Zambia, Eswatini, and Lesotho. Methods Adolescents were tested for HIV using national rapid testing algorithms. Viral load (VL) suppression (VLS) was defined as VL, Based on national surveys, fewer than half of adolescents living with human immunodeficiency virus (HIV) in 5 countries in southern Africa were virally suppressed, and 68.7% classified as perinatally infected had undiagnosed HIV or HIV diagnosed at age ≥10 years.

Background Intracellular tenofovir diphosphate (TFV-DP) concentration in dried blood spots (DBSs) is used to monitor cumulative pre-exposure prophylaxis (PrEP) adherence. We evaluated TFV-DP in DBSs following daily oral PrEP (emtricitabine 200 mg/tenofovir diphosphate 300 mg) among pregnant and postpartum adolescent girls and young women (AGYW). Methods Directly observed PrEP was administered for 12 weeks in a pregnancy (14–24 weeks’ gestation, n = 20) and postpartum (6–12 weeks postpartum, n = 20) group of AGYW aged 16–24 years in sub-Saharan Africa. Weekly DBS TFV-DP was measured by validated liquid chromatography–tandem mass spectrometry assay. Week 12 TFV-DP distributions were compared between groups with Wilcoxon test. Population pharmacokinetic models were fit to estimate steady-state concentrations and create benchmarks for adherence categories. Baseline correlates of TFV-DP were evaluated. Results Median age was 20 (IQR, 19–22) years. Of 3360 doses, 3352 (>99%) were directly observed. TFV-DP median (IQR) half-life was 10 (7–12) days in pregnancy and 17 (14–21) days postpartum, with steady state achieved by 5 and 8 weeks, respectively. Observed median (IQR) steady-state TFV-DP was 965 fmol/punch (691–1166) in pregnancy versus 1406 fmol/punch (1053–1859) postpartum (P = .006). Modeled median steady-state TFV-DP was 881 fmol/punch (667–1105) in pregnancy versus 1438 fmol/punch (1178–1919) postpartum. In pooled analysis, baseline creatinine clearance was associated with observed TFV-DP concentrations. Conclusions TFV-DP in African AGYW was approximately one-third lower in pregnancy than postpartum. These Population-specific benchmarks can be used to guide PrEP adherence support in pregnant/postpartum African women. Clinical Trials Registration NCT03386578, Concentrations of tenofovir diphosphate in dried blood spots were approximately one-third lower during pregnancy than postpartum after 12 weeks of directly observed dosing among African adolescent girls and young women on daily pre-exposure prophylaxis. We recommend population-specific benchmarks for adherence support.

Background In 2010, the World Health Organization (WHO) revised dosing guidelines for treatment of childhood tuberculosis. Our aim was to investigate first-line antituberculosis drug exposures under these guidelines, explore dose optimization using the current dispersible fixed-dose combination (FDC) tablet of rifampicin/isoniazid/pyrazinamide; 75/50/150 mg, and suggest a new FDC with revised weight bands. Methods Children with drug-susceptible tuberculosis in Malawi and South Africa underwent pharmacokinetic sampling while receiving first-line tuberculosis drugs as single formulations according the 2010 WHO recommended doses. Nonlinear mixed-effects modeling and simulation was used to design the optimal FDC and weight-band dosing strategy for achieving the pharmacokinetic targets based on literature-derived adult AUC0-24h for rifampicin (38.7–72.9), isoniazid (11.6–26.3), and pyrazinamide (233–429 mg ∙ h/L). Results In total, 180 children (42% female; 13.9% living with human immunodeficiency virus [HIV]; median [range] age 1.9 [0.22–12] years; weight 10.7 [3.20–28.8] kg) were administered 1, 2, 3, or 4 FDC tablets (rifampicin/isoniazid/pyrazinamide 75/50/150 mg) daily for 4–8, 8–12, 12–16, and 16–25 kg weight bands, respectively. Rifampicin exposure (for weight and age) was up to 50% lower than in adults. Increasing the tablet number resulted in adequate rifampicin but relatively high isoniazid and pyrazinamide exposures. Administering 1, 2, 3, or 4 optimized FDC tablets (rifampicin/isoniazid/pyrazinamide 120/35/130 mg) to children Conclusions Current pediatric FDC doses resulted in low rifampicin exposures. Optimal dosing of all drugs cannot be achieved with the current FDCs. We propose a new FDC formulation and revised weight bands.

AIMS Patients hospitalized at the time of human immunodeficiency virus-associated tuberculosis (HIV-TB) diagnosis have high early mortality. We hypothesized that compared to outpatients, there would be lower anti-TB drug exposure in hospitalized HIV-TB patients, and amongst hospitalized patients exposure would be lower in patients who die or have high lactate (a sepsis marker). METHODS We performed pharmacokinetic sampling in hospitalized HIV-TB patients and outpatients. Plasma rifampicin, isoniazid and pyrazinamide concentrations were measured in samples collected predose and at 1, 2.5, 4, 6 and 8 hours on the third day of standard anti-TB therapy. Twelve-week mortality was ascertained for inpatients. Noncompartmental pharmacokinetic analysis was performed. RESULTS Pharmacokinetic data were collected in 59 hospitalized HIV-TB patients and 48 outpatients. Inpatient 12-week mortality was 11/59 (19%). Rifampicin, isoniazid and pyrazinamide exposure was similar between hospitalized and outpatients (maximum concentration [Cmax ]: 7.4 vs 8.3 μg mL-1 , P = .223; 3.6 vs 3.5 μg mL-1 , P = .569; 50.1 vs 46.8 μg mL-1 , P = .081; area under the concentration-time curve from 0 to 8 hours: 41.0 vs 43.8 mg h L-1 , P = 0.290; 13.5 vs 12.4 mg h L-1 , P = .630; 316.5 vs 292.2 mg h L-1 , P = .164, respectively) and not lower in inpatients who died. Rifampicin and isoniazid Cmax were below recommended ranges in 61% and 39% of inpatients and 44% and 35% of outpatients. Rifampicin exposure was higher in patients with lactate >2.2 mmol L-1 . CONCLUSION Mortality in hospitalized HIV-TB patients was high. Early anti-TB drug exposure was similar to outpatients and not lower in inpatients who died. Rifampicin and isoniazid Cmax were suboptimal in 61% and 39% of inpatients and rifampicin exposure was higher in patients with high lactate. Treatment strategies need to be optimized to improve survival.

Fusidic acid (FA) has previously been shown to be rapidly metabolized in rodents to its C-3 epimer, which has significantly lower antimycobacterial activity relative to FA. This was in part hypothesized to account for FA's lack of in vivo efficacy in a mouse model of tuberculosis despite potent in vitro antimycobacterial activity. In the current work, we hypothesized that C-3 alkyl ester prodrugs of FA would deliver higher levels of the drug and prevent the rapid metabolism observed upon administration of FA in its original form. Pharmacokinetic analysis of FA and its 3-ketofusidic acid metabolite as well as novel C-3 alkyl ester prodrugs of FA revealed that FA has low exposure in mice due to rapid metabolism to a species-specific metabolite, 3-epifusidic acid. The C-3 alkyl ester prodrugs showed improved absorption and tissue distribution in pharmacokinetic and organ distribution experiments. These results support the original objective of the FA C-3 ester prodrugs to improve drug concentrations and tissue distribution.

Background Darunavir/ritonavir is better tolerated than lopinavir/ritonavir and has a higher genetic barrier to resistance. Co-administration with rifampicin has been contraindicated as a significant reduction in darunavir exposure is expected. This is a barrier to darunavir/ritonavir use where TB is endemic. Objectives To evaluate the safety and pharmacokinetic profile of adjusted doses of darunavir/ritonavir with rifampicin. Methods Virally suppressed participants on second-line lopinavir/ritonavir-based ART were switched to darunavir/ritonavir 800/100 mg q24h. In sequence: rifampicin was added; the dose of ritonavir was escalated; and darunavir was increased (darunavir/ritonavir 1600/200 mg q24h and 800/100 mg q12h were given in randomized sequence with rifampicin). Darunavir plasma concentrations were measured on the seventh/last day of each treatment period. To prevent viral rebound, dolutegravir (50 mg q12h) was added during rifampicin administration and for 1 week thereafter. Clinical events, ALT and bilirubin were monitored every 2–3 days during rifampicin administration. Results A total of 17/28 participants started study treatment. Six (35.3%) were withdrawn for symptomatic hepatitis with severe ALT elevations, developing after 9–11 days of rifampicin and 2–4 days of ritonavir 200 mg. The study was stopped prematurely due to this high rate of hepatotoxicity. Only four participants completed the study. All hepatotoxicity resolved on withdrawal of study treatment. All participants were successfully re-established on their lopinavir/ritonavir-based regimen. After doubling the darunavir/ritonavir doses on rifampicin, darunavir pre-dose concentrations approached those on standard doses without rifampicin for q12h doses, but not for q24h doses. Conclusions Adjusted doses of darunavir/ritonavir with rifampicin had unacceptable risk of hepatotoxicity. Darunavir trough concentrations were markedly reduced with the daily adjusted dose.

OBJECTIVE: The toxicity associated with the use of kanamycin includes irreversible hearing loss. There is limited data describing the relationship between hearing loss and kanamycin pharmacokinetics (PK). We explored the association of kanamycin PK with hearing loss in patients on MDR-TB treatment. DESIGN: We prospectively recruited patients on kanamycin-based MDR-TB treatment in Cape Town. Hearing thresholds from 0.25 to 16 kHz were tested at baseline and at 4, 8 and 12 weeks. We determined kanamycin concentrations at steady-state in serial plasma samples over 10 hours, and explored factors associated with hearing loss. STUDY SAMPLE: One hundred and two participants including 58 (56.9%) men had analysable audiometric data; median age was 34.9 years, 65 (63.7%) were HIV-positive, and 24 (23.5%) had been treated for MDR-TB previously. RESULTS: Eighty-four participants (82.4%) developed hearing loss. We found a 3% (95% CI: 1 to 6%, p=0.028) increased risk of cochleotoxicity for each 10μg•hr/L increase in 0–10 hour AUC. CONCLUSION: We describe a high incidence of hearing loss in MDR-TB patients treated with kanamycin, with higher AUC(0–10) significantly associated with hearing loss.

SETTING: Treatment outcomes in multidrug-resistant tuberculosis (MDR-TB) are poor. Due to drug toxicity and a long treatment duration, approximately half of patients are treated successfully. Medication is often crushed for patients who have difficulty swallowing whole tablets. Whether crushing tablets affects drug exposure in MDR-TB treatment is not known.OBJECTIVE AND DESIGN: We performed a sequential pharmacokinetic study in patients aged >18 years on MDR-TB treatment at two hospitals in Cape Town, South Africa. We compared the bioavailability of pyrazinamide, moxifloxacin, isoniazid (INH), ethambutol and terizidone when the tablets were crushed and mixed with water before administration vs. swallowed whole. We sampled blood at six time points over 10 h under each condition separated by 2 weeks. Non-compartmental analysis was used to derive the key pharmacokinetic measurements.RESULTS: Twenty participants completed the study: 15 were men, and the median age was 31.5 years. There was a 42% reduction in the area under the curve AUC0–10 of INH when the tablets were crushed compared with whole tablets (geometric mean ratio 58%; 90%CI 47–73). Crushing tablets of pyrazinamide, moxifloxacin, ethambutol and terizidone did not affect the bioavailability significantly.CONCLUSION: We recommend that crushing of INH tablets in the MDR-TB treatment regimen be avoided. Paediatric INH formulations may be a viable alternative if the crushing of INH tablets is indicated.

Linezolid is widely used for drug-resistant tuberculosis (DR-TB) but has a narrow therapeutic index. To inform dose optimization, we aimed to characterize the population pharmacokinetics of linezolid in South African participants with DR-TB and explore the effect of covariates, including HIV coinfection, on drug exposure. Data were obtained from pharmacokinetic substudies in a randomized controlled trial and an observational cohort study, both of which enrolled adults with drug-resistant pulmonary tuberculosis. Participants underwent intensive and sparse plasma sampling. We analyzed linezolid concentration data using nonlinear mixed-effects modeling and performed simulations to estimate attainment of putative efficacy and toxicity targets. A total of 124 participants provided 444 plasma samples; 116 were on the standard daily dose of 600 mg, while 19 had dose reduction to 300 mg due to adverse events. Sixty-one participants were female, 71 were HIV-positive, and their median weight was 56 kg (interquartile range [IQR], 50 to 63). In the final model, typical values for clearance and central volume were 3.57 liters/h and 40.2 liters, respectively. HIV coinfection had no significant effect on linezolid exposure. Simulations showed that 600-mg dosing achieved the efficacy target (area under the concentration-time curve for the free, unbound fraction of the drug [[Formula: see text] at a MIC level of 0.5 mg/liter) with 96% probability but had 56% probability of exceeding safety target ([Formula: see text]. The 300-mg dose did not achieve adequate efficacy exposures. Our model characterized population pharmacokinetics of linezolid in South African patients with DR-TB and supports the 600-mg daily dose with safety monitoring.

BACKGROUND: High-dose isoniazid (INHH) (15–20 mg/kg/day) could be administered to overcome low-level INH resistance, but pharmacokinetic data are sparse.METHODS: This observational study included South African children (H as preventive therapy, or treatment for multidrug-resistant TB (MDR-TB) exposure or disease. Pharmacokinetic sampling was performed after an INH dose of 20 mg/kg. Non-compartmental analysis and multivariable regression models were used to evaluate associations of key covariates with area under the curve (AUC0–24) and maximum concentration (Cmax). AUC and Cmax values were compared against proposed adult targets.RESULTS: Seventy-seven children were included, with median age of 3.7 years; 51 (66%) had MDR-TB disease and 26 (34%) had MDR-TB exposure. Five were HIV-positive, of whom four were ≥5 years old. The median AUC0–24 was 19.46 µgh/mL (IQR 10.76–50.06) and Cmax was 5.14 µg/mL (IQR 2.69–13.2). In multivariable analysis of children aged 0–24 (geometric mean ratio GMR 0.19, 95% CI 0.15–0.26; P < 0.001) and Cmax (GMR 0.20, 95% CI 0.15–0.26; P < 0.001).CONCLUSIONS: INH concentrations in children with MDR-TB disease were much lower than expected, but comparable to previous reports in children with MDR-TB exposure. Further studies should confirm these findings and explore possible causes.

The therapeutic repertoire for tuberculosis (TB) remains limited despite the existence of many TB drugs that are highly active in in vitro models and possess clinical utility. Underlying the lack of efficacy in vivo is the inability of TB drugs to penetrate microenvironments inhabited by the causative agent, Mycobacterium tuberculosis, including host alveolar macrophages. Here, we determined the ability of the phenoxazine PhX1 previously shown to be active against M. tuberculosis in vitro to differentially penetrate murine compartments, including plasma, epithelial lining fluid, and isolated epithelial lining fluid cells. We also investigated the extent of permeation into uninfected and M. tuberculosis-infected human macrophage-like Tamm-Horsfall protein 1 (THP-1) cells directly and by comparing to results obtained in vitro in synergy assays. Our data indicate that PhX1 (4,750 ± 127.2 ng/ml) penetrates more effectively into THP-1 cells than do the clinically used anti-TB agents, rifampin (3,050 ± 62.9 ng/ml), moxifloxacin (3,374 ± 48.7 ng/ml), bedaquiline (4,410 ± 190.9 ng/ml), and linezolid (770 ± 14.1 ng/ml). Compound efficacy in infected cells correlated with intracellular accumulation, reinforcing the perceived importance of intracellular penetration as a key drug property. Moreover, we detected synergies deriving from redox-stimulatory combinations of PhX1 or clofazimine with the novel prenylated amino-artemisinin WHN296. Finally, we used compound synergies to elucidate the relationship between compound intracellular accumulation and efficacy, with PhX1/WHN296 synergy levels shown to predict drug efficacy. Collectively, our data support the utility of the applied assays in identifying in vitro active compounds with the potential for clinical development. IMPORTANCE This study addresses the development of novel therapeutic compounds for the eventual treatment of drug-resistant tuberculosis. Tuberculosis continues to progress, with cases of Mycobacterium tuberculosis (M. tuberculosis) resistance to first-line medications increasing. We assess new combinations of drugs with both oxidant and redox properties coupled with a third partner drug, with the focus here being on the potentiation of M. tuberculosis-active combinations of compounds in the intracellular macrophage environment. Thus, we determined the ability of the phenoxazine PhX1, previously shown to be active against M. tuberculosis in vitro, to differentially penetrate murine compartments, including plasma, epithelial lining fluid, and isolated epithelial lining fluid cells. In addition, the extent of permeation into human macrophage-like THP-1 cells and H37Rv-infected THP-1 cells was measured via mass spectrometry and compared to in vitro two-dimensional synergy and subsequent intracellular efficacy. Collectively, our data indicate that development of new drugs will be facilitated using the methods described herein.

Given the high prevalence of multidrug-resistant (MDR)-TB in high HIV burden settings, it is important to identify potential drug-drug interactions between MDR-TB treatment and widely used nucleoside reverse transcriptase inhibitors (NRTIs) in HIV-positive children. Population pharmacokinetic models were developed for lamivudine (n = 54) and abacavir (n = 50) in 54 HIV-positive children established on NRTIs; 27 with MDR-TB (combinations of high-dose isoniazid, pyrazinamide, ethambutol, ethionamide, terizidone, fluoroquinolones, and amikacin), and 27 controls without TB. Two-compartment models with first-order elimination and transit compartment absorption described both lamivudine and abacavir pharmacokinetics, respectively. Allometric scaling with body weight adjusted for the effect of body size. Clearance was predicted to reach half its mature value ∼2 (lamivudine) and ∼3 (abacavir) months after birth, with completion of maturation for both drugs at ∼2 years. No significant difference was found in key pharmacokinetic parameters of lamivudine and abacavir when co-administered with routine drugs used for MDR-TB in HIV-positive children.

Ethionamide is recommended as part of regimens to treat multidrug-resistant and rifampicin-resistant tuberculosis. This study was conducted to (i) describe the distribution of ethionamide MICs, (ii) describe the pharmacokinetics of ethionamide, and (iii) determine the probability of attaining target area under the concentration-time curve from 0 to 24 h (AUC(0–24))/MIC values associated with suppression of resistant subpopulation and microbial kill. Participants received 15 to 20 mg of drug/kg of body weight of ethionamide daily (in 500- or 750-mg doses) as part of a multidrug regimen. Pretreatment MICs of ethionamide for Mycobacterium tuberculosis sputum isolates were determined using Sensititre MYCOTB MIC plates. Plasma concentrations of ethionamide (measured predose and at 2, 4, 6, 8, and 10 h postdose) were available for 84 patients. A one-compartment disposition model, including a liver compartment capturing hepatic extraction, best described ethionamide pharmacokinetics. Clearance and volume were allometrically scaled using fat-free mass. Isoniazid coadministration reduced ethionamide clearance by 31%, resulting in a 44% increase in AUC(0–24). The median (range) MIC (n = 111) was 2.5 mg/liter (40 mg/liter). Simulations showed increased daily doses of ethionamide (1,250 mg, 1,500 mg, and 1,750 mg for patients weighing ≤45 kg, 46 to 70 kg, and >70 kg, respectively) resulted in the probability of attaining an area under the concentration-time curve from 0 to 24 h for the free, unbound fraction of a drug (fAUC(0–24))/MIC ratio of ≥42 in more than 90% of patients only at the lowest MIC of 0.3 mg/liter. The WHO-recommended doses of ethionamide do not achieve target concentrations even for the lowest MIC measured in the cohort.

As artemisinin combination therapies (ACTs) are compromised by resistance, we are evaluating triple combination therapies (TACTs) comprising an amino-artemisinin, a redox drug, and a third drug with a different mode of action. Thus, here we briefly review efficacy data on artemisone, artemiside, other amino-artemisinins, and 11-aza-artemisinin and conduct absorption, distribution, and metabolism and excretion (ADME) profiling in vitro and pharmacokinetic (PK) profiling in vivo via intravenous (i.v.) and oral (p.o.) administration to mice. The sulfamide derivative has a notably long murine microsomal half-life (t1/2 > 150 min), low intrinsic liver clearance and total plasma clearance rates (CLint 189.4, CLtot 32.2 ml/min/kg), and high relative bioavailability (F = 59%). Kinetics are somewhat similar for 11-aza-artemisinin (t1/2 > 150 min, CLint = 576.9, CLtot = 75.0 ml/min/kg), although bioavailability is lower (F = 14%). In contrast, artemether is rapidly metabolized to dihydroartemisinin (DHA) (t1/2 = 17.4 min) and eliminated (CLint = 855.0, CLtot = 119.7 ml/min/kg) and has low oral bioavailability (F) of 2%. While artemisone displays low t1/2 of 150 min and a reduced CLint of 37.4 ml/min/kg. Artemiside has t1/2 of 12.4 min, CLint of 673.9, and CLtot of 129.7 ml/kg/min, likely a reflection of its surprisingly rapid metabolism to artemisone, reported here for the first time. DHA is not formed from any amino-artemisinin. Overall, the efficacy and PK data strongly support the development of selected amino-artemisinins as components of new TACTs.

Background Pre-exposure prophylaxis (PrEP) is highly effective and an important prevention tool for African adolescent girls and young women (AGYW), but adherence and persistence are challenging. PrEP adherence support strategies for African AGYW were studied in an implementation study. Methods and findings HIV Prevention Trials Network (HPTN) 082 was conducted in Cape Town, Johannesburg (South Africa) and Harare (Zimbabwe) from October 2016 to October 2018 to evaluate PrEP uptake, persistence, and the effect of drug level feedback on adherence. Sexually active HIV–negative women ages 16–25 were offered PrEP and followed for 12 months; women who accepted PrEP were randomized to standard adherence support (counseling, 2-way SMS, and adherence clubs) or enhanced adherence support with adherence feedback from intracellular tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS). PrEP uptake, persistence through 12 months (no PrEP hold or missed visits), and adherence were assessed. The primary outcome was high adherence (TFV-DP ≥700 fmol/punch) at 6 months, compared by study arm. Of 451 women enrolled, median age was 21 years, and 39% had curable sexually transmitted infections (STIs). Most (95%) started PrEP, of whom 55% had uninterrupted PrEP refills through 12 months. Of those with DBS, 84% had detectable TFV-DP levels at month 3, 57% at month 6, and 31% at month 12. At 6 months, 36/179 (21%) of AGYW in the enhanced arm had high adherence and 40/184 (22%) in the standard adherence support arm (adjusted odds ratio [OR] of 0.92; 95% confidence interval [CI] 0.55, 1.34; p = 0.76). Four women acquired HIV (incidence 1.0/100 person-years), with low or undetectable TFV-DP levels at or prior to seroconversion, and none of whom had tenofovir or emtricitabine resistance mutations. The study had limited power to detect a modest effect of drug level feedback on adherence, and there was limited awareness of PrEP at the time the study was conducted. Conclusions In this study, PrEP initiation was high, over half of study participants persisted with PrEP through month 12, and the majority of young African women had detectable TFV-DP levels through month 6 with one-fifth having high adherence. Drug level feedback in the first 3 months of PrEP use did not increase the proportion with high adherence at month 6. HIV incidence was 1% in this cohort with 39% prevalence of curable STIs and moderate PrEP adherence. Strategies to support PrEP use and less adherence-dependent formulations are needed for this population. Trial registration ClinicalTrials.gov NCT02732730., Connie Celum and co-workers report on use of pre-exposure prophylaxis by young women in Southern Africa., Author summary Why was this study done? HIV incidence remains high (4%) in young African women. Pre-exposure prophylaxis (PrEP) has over 90% efficacy in preventing HIV infection when used consistently and could reduce HIV incidence in young African women. Adherence was low in placebo-controlled efficacy trials of oral PrEP among young African women. Qualitative research among a subset of women at unblinding of the efficacy trials indicated that women thought drug level feedback would support their adherence and foster open discussions with counselors about adherence. Drug level feedback should be evaluated as a strategy to increase PrEP adherence among young African women. What did the researchers do and find? A cohort of 451 young women in South Africa and Zimbabwe who were at risk for HIV were recruited and offered PrEP, among whom 95% initiated PrEP. Half were randomized to receive drug level feedback at months 2 and 3 plus the standard adherence support package (2-way SMS, brief counseling, and optional PrEP adherence clubs), and half received the standard adherence support package without drug level feedback. The majority had detectable intracellular drug levels through the first 6 months, and 21% had high adherence at month 6, defined as intracellular tenofovir-diphosphate (TFV-DP) ≥700 fmol/punch. PrEP adherence did not differ based on whether they were randomized to receive drug level feedback at months 2 and 3 or to standard of care (SOC) PrEP adherence support without drug level feedback. What do these findings mean? Drug level feedback was not associated with improved PrEP adherence among young African women. Additional strategies need to be evaluated for their effectiveness in increasing adherence with oral PrEP for young African women. Longer-acting and less user-dependent PrEP formulations may also overcome adherence challenges with daily oral PrEP.

BackgroundRifampicin doses of 40 mg/kg in adults are safe and well tolerated, may shorten anti-TB treatment and improve outcomes, but have not been evaluated in children.ObjectivesTo characterize the pharmacokinetics and safety of high rifampicin doses in children with drug-susceptible TB.Patients and methodsThe Opti-Rif trial enrolled dosing cohorts of 20 children aged 0–12 years, with incremental dose escalation with each subsequent cohort, until achievement of target exposures or safety concerns. Cohort 1 opened with a rifampicin dose of 15 mg/kg for 14 days, with a single higher dose (35 mg/kg) on day 15. Pharmacokinetic data from days 14 and 15 were analysed using population modelling and safety data reviewed. Incrementally increased rifampicin doses for the next cohort (days 1–14 and day 15) were simulated from the updated model, up to the dose expected to achieve the target exposure [235 mg/L·h, the geometric mean area under the concentration–time curve from 0 to 24 h (AUC0–24) among adults receiving a 35 mg/kg dose].ResultsSixty-two children were enrolled in three cohorts. The median age overall was 2.1 years (range = 0.4–11.7). Evaluated doses were ∼35 mg/kg (days 1–14) and ∼50 mg/kg (day 15) for cohort 2 and ∼60 mg/kg (days 1–14) and ∼75 mg/kg (day 15) for cohort 3. Approximately half of participants had an adverse event related to study rifampicin; none was grade 3 or higher. A 65–70 mg/kg rifampicin dose was needed in children to reach the target exposure.ConclusionsHigh rifampicin doses in children achieved target exposures and the doses evaluated were safe over 2 weeks.

Aims Describe the pharmacokinetics (PK) of the antiretroviral drugs abacavir and lamivudine in malnourished paediatric patients and relate to viral load outcomes after 12 and 48 weeks of treatment. Methods Severely malnourished human immunodeficiency virus-infected children were randomized to early (within 14 days) or delayed (after nutritional recovery) initiation of antiretroviral treatment (ART) using World Health Organization weight-band dosages. Abacavir and lamivudine concentrations were measured as a secondary objective on day 1 and day 14 and patients were followed-up to week 48. Population PK of abacavir and lamivudine were described using NONMEM. Results In total, 623 abacavir and 627 lamivudine concentrations were collected from 75 paediatric patients aged 0.1-10.8 (median 1.4) years. Abacavir PK was described by a 2-compartment model, patients randomized to early ART showed increased bioavailability of 31%. Apparent clearance (CL/F, L/h/7 kg) of abacavir increased from day 1 to day 14 from 3.33 (95% confidence interval 2.71-4.12) to 5.86 (95% confidence interval 4.78-7.3). A 1-compartment model described lamivudine PK, variability on CL/F was explained by maturation with age, with age at half-matured CL/F being 4 months. For both drugs allometrically scaled total body weight was related to CL/F and apparent volume of distribution. PK exposure did not correlate with virological outcomes or death at 12 or 48 weeks. Conclusion Increases in Abacavir's CL/F between day 1 to day 14, bioavailability and PK variability with early start of ART was found in this cohort of severely malnourished children; however, these changes did not influence virological outcomes. The study supports the use of weight-band dosage tables.

Pilot studies suggest that ritonavir-boosted darunavir could show high efficacy at doses below those currently approved. We investigated whether switch to 400 mg of darunavir boosted with 100 mg ritonavir once daily could show equivalent efficacy to continuation of ritonavir-boosted lopinavir (a protease inhibitor commonly used in low-income and middle-income countries) for individuals with HIV RNA suppression.In the WRHI 052 study, a randomised, parallel-group, open-label, non-inferiority phase 3 trial, adults who were HIV-1 positive were enrolled in Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa. Eligible participants were 18 years or older, who tolerated ritonavir-boosted lopinavir in combination with two nucleoside analogues (standard of care) for 6 months or more, and had plasma HIV-1 RNA of less than 50 copies per mL within 60 days of enrolment. We randomly assigned participants (1:1), using a computer-generated randomisation plan, to switch to darunavir (400 mg) boosted with ritonavir (100 mg) once daily or remain on ritonavir-boosted lopinavir (800 mg [plus 200 mg ritonavir]), with nucleoside analogues left unchanged. The primary endpoint was the proportion of patients with less than 50 HIV-1 RNA copies per mL at week 48 (US Food and Drug Administration snapshot algorithm; non-inferiority margin -4%). Primary and safety analyses included participants receiving at least one dose of darunavir boosted with ritonavir. This trial is registered with ClinicalTrials.gov, number NCT02671383.Between June 30, 2016, and June 15, 2017, 148 participants were assigned to ritonavir-boosted darunavir 400 mg and 152 continued on their lopinavir-containing regimen. Four (3%) patients in the darunavir group and three (2%) in the lopinavir group discontinued before week 48. At week 48, darunavir was non-inferior to lopinavir for the primary outcome (142 [96%] of 148 participants on darunavir had50 HIV-1 RNA copies per mL vs 143 [94%] of 152 participants on lopinavir; difference 1·9% [95% CI -3·4 to 7·3]), with a predefined margin of -4%. More participants taking darunavir (30 [20%] participants) had drug-related adverse events than those on lopinavir (eight [5%]), but the adverse events were generally asymptomatic and resolved when switching back to lopinavir. Elevated liver transaminase in three (1%; one symptomatic) darunavir participants led to study withdrawal; all transaminase elevations resolved on restarting lopinavir.Low-dose ritonavir-boosted darunavir might be a safe and efficacious switch option to maintain HIV suppression for patients on lopinavir. However, an adequately powered and designed study in viraemic participants is needed.South African Medical Research Council, United States Agency for International Development, and US National Institute of Allergy and Infectious Diseases.

Tenofovir-diphosphate (TFV-DP) in dried blood spots (DBS) is an objective long-term adherence measure, but data are limited on its ability to predict virologic suppression (VS) in people on antiretroviral (ARV) treatment. There are also no data comparing DBS TFV-DP with plasma ARV concentrations as predictors of VS.Women who were on a first-line regimen of tenofovir, emtricitabine, and efavirenz (EFV) were enrolled in a cross-sectional study. Plasma EFV and tenofovir (TFV), DBS TFV-DP assays, and 30-day self-reported adherence were evaluated as predictors of VS (50 copies/mL) with the area under the curve of receiver operating characteristics and logistic regression.We enrolled 137 women; mean age of 33 years; median 4 years on antiretroviral therapy; 88 (64%) had VS. In receiver operating characteristics analyses: DBS TFV-DP [0.926 (95% CI: 0.876 to 0.976)] had a higher area under the curve than plasma TFV [0.864 (0.797 to 0.932); P = 0.006], whereas plasma EFV [0.903 (0.839-0.967)] was not significantly different from DBS TFV-DP (P = 0.138) or plasma TFV (P = 0.140); all ARV assays performed better than self-report. The association of TFV-DP in DBS with VS strengthened with increasing concentrations [reference350 fmol/punch: 350-699 fmol/punch aOR 37 (8-178); 700-1249 fmol/punch aOR 47 (13-175); ≥1250 fmol/punch aOR 175 (20-1539)]. "White coat adherence" (defined as DBS TFV-DP350 fmol/punch with detectable plasma TFV) was only detected in 4 women.Plasma EFV, TFV, and DBS TFV-DP were all strong predictors of VS. EFV or TFV assays have potential for development as point-of-care assays for use as objective adherence measures in resource-limited settings.

Objectives The current WHO weight-based dosing recommendations for efavirenz result in a wide variability of drug exposure in children. Our objectives are to characterize the effects of rifampicin- and isoniazid-containing anti-TB therapy and CYP2B6 activity on efavirenz concentrations in children, using non-linear mixed-effects modelling. Methods This is a pharmacokinetic (PK) substudy of a prospective study that examined the interactions between anti-TB therapy and efavirenz in HIV-infected children with and without TB. PK samples were obtained 4 weeks after starting efavirenz (PK1) and repeated 4 weeks after completing TB therapy (PK2) in TB/HIV coinfected patients. Drug concentrations were measured using LC-MS/MS. Composite CYP2B6 516/983/15582 genotype was determined. Population PK modelling was performed in Monolix. Simulations were performed to obtain the predicted mid-dose concentrations (C12). Results One hundred and five HIV-infected Ghanaian children (46 with TB/HIV) were included. The median age and weight were 7 years and 19 kg. The efavirenz concentrations over time were adequately described using a one-compartment model. Weight, composite CYP2B6 genotype and PK visit had a significant influence on the PK parameters, while TB therapy had no significant effect. Simulations showed adequate C12 for intermediate composite CYP2B6 metabolizers only. Conclusions Our model showed that rifampicin- and isoniazid-containing anti-TB therapy does not influence efavirenz PK parameters. On the other hand, it describes the effect of efavirenz autoinduction after completing TB treatment. In addition, dosing efavirenz in children based only on weight results in a large variability in drug exposure. We propose dose adjustments for slow and extensive composite CYP2B6 metabolizers.

Background In patients with tuberculous pericarditis [TBP] adjunctive prednisolone reduces the incidence of constrictive pericarditis. It is unknown whether prednisolone permeates adequately into pericardial fluid. Drug measurements in pericardial fluid require invasive procedures, and thus less invasive methods are needed to perform full pharmacokinetic characterization of prednisolone in large numbers of patients. We sought to evaluate the relationship between prednisolone concentrations in pericardial fluid, plasma, and saliva. Methods Plasma, pericardial fluid, and saliva samples were collected at 7 time points from TBP patients randomized to 120 mg prednisolone or placebo. Compartmental pharmacokinetic parameters, peak concentration [Cmax], and 0–24 h area under the concentration-time curve [AUC0–24] were identified in plasma, saliva and pericardial fluid. Results There were five patients each in the prednisolone and placebo groups. Prednisolone concentrations were best described using a one compartment model. The absorption half-life into plasma was 1 h, while that into pericardial fluid was 9.4 h, which led to a median time-to-maximum concentration in plasma of 2.0 h versus 5.0 h in pericardial fluid [p = 0.048]. The concentration-time profiles in pericardial fluid versus plasma exhibited system hysteresis. The pericardial fluid-to-plasma Cmax peak concentration ratio was 0.28 (p = 0.032), while the AUC0–24 ratio was 0.793. The concentration-time profiles in saliva had a similar shape to those in plasma, but the saliva-to-plasma Cmax was 0.59 [p = 0.032]. Conclusion The prednisolone AUC0–24 achieved in pericardial fluid approximates that in plasma, but the Cmax is low due to delayed absorption. Saliva can be used as surrogate sampling site for pericardial fluid prednisolone.

OBJECTIVE: There is increasing interest in home based testing and treatment of HIV to expand access to treatment in sub-Saharan Africa. Such programs rely on self-reported HIV history and use of antiretroviral therapy (ART). However, the accuracy of self-reported ART use in community settings is not well described. In this study, we compared self-reported ART (SR-ART) use in a home based survey against biological exposure to ART (BE-ART), in a population study of older adults in South Africa. METHODS: Health and Aging in Africa: a Longitudinal Study of an INDEPTH community in South Africa (HAALSI) is a cohort of adults aged 40+. The baseline home-based interview included self-reported HIV status and ART use. All participants also underwent biological testing for HIV antibodies, viral load and exposure to emtricitabine (FTC) or lamivudine (3TC), which are included in all first-line and second-line ART regimens in the public-sector South African HIV program. We calculated the performance characteristics for SR-ART compared to BE-ART and fit multivariable logistic regression models to identify correlates of invalid SR-ART responses. RESULTS: Of 4,560 HAALSI participants with a valid HIV test result available, 1,048 (23%) were HIV-positive and 734 [70% of people living with HIV (PLWH)] were biologically validated ART users (BE-ART). The sensitivity of SR-ART use was 64% (95% CI: 61–68%) and the specificity was 94% (95% CI: 91–96%); the positive predictive value (PPV) was 96% (95% CI: 94–98%) and negative predictive value (NPV) was 52% (95% CI: 48–56%). We found no sociodemographic predictors of accurate SR-ART use. CONCLUSIONS: Over one in three individuals with detectable ART in their blood denied current ART use during a home-based interview. These results demonstrate ongoing stigma related to HIV and its treatment, and have important implications for community health worker programs, clinical programs, and research studies planning community-based ART initiation in the region.

Background A safe, effective vaccine is essential to eradicating human immunodeficiency virus (HIV) infection. A canarypox-protein HIV vaccine regimen (ALVAC-HIV plus AIDSVAX B/E) showed modest efficacy in reducing infection in Thailand. An analogous regimen using HIV-1 subtype C virus showed potent humoral and cellular responses in a phase 1-2a trial in South Africa. Efficacy data and additional safety data were needed for this regimen in a larger population in South Africa. Methods In this phase 2b-3 trial, we randomly assigned 5404 adults without HIV-1 infection to receive the vaccine (2704 participants) or placebo (2700 participants). The vaccine regimen consisted of injections of ALVAC-HIV at months 0 and 1, followed by four booster injections of ALVAC-HIV plus bivalent subtype C gp120-MF59 adjuvant at months 3, 6, 12, and 18. The primary efficacy outcome was the occurrence of HIV-1 infection from randomization to 24 months. Results In January 2020, prespecified criteria for nonefficacy were met at an interim analysis; further vaccinations were subsequently halted. The median age of the trial participants was 24 years; 70% of the participants were women. The incidence of adverse events was similar in the vaccine and placebo groups. During the 24-month follow-up, HIV-1 infection was diagnosed in 138 participants in the vaccine group and in 133 in the placebo group (hazard ratio, 1.02; 95% confidence interval, 0.81 to 1.30; P = 0.84). Conclusions The ALVAC-gp120 regimen did not prevent HIV-1 infection among participants in South Africa despite previous evidence of immunogenicity. (HVTN 702 ClinicalTrials.gov number, NCT02968849.).

BackgroundHigher doses of intravenous rifampicin may improve outcomes in tuberculous meningitis but is impractical in high burden settings. We hypothesized that plasma rifampicin exposures would be similar between oral 35 mg/kg and intravenous 20 mg/kg, which has been proposed for efficacy trials in tuberculous meningitis.Materials and methodsWe performed a randomized parallel group pharmacokinetic study nested within a clinical trial of intensified antimicrobial therapy for tuberculous meningitis. HIV-positive participants with tuberculous meningitis were recruited from South African hospitals and randomized to one of three rifampicin dosing groups: standard (oral 10 mg/kg), high dose (oral 35 mg/kg), and intravenous (intravenous 20 mg/kg). Intensive pharmacokinetic sampling was done on day 3. Data were described using non-compartmental analysis and exposures compared by geometric mean ratio (GMR).ResultsForty-six participants underwent pharmacokinetic sampling (standard dose, n = 17; high dose oral, n= 15; IV, n = 14). Median CD4 count was 130 cells/mm3 (IQR 66 −253). Geometric mean AUC0-∞ was 47.7 µg·h/mL (90% CI, 33.2 – 68.5) for standard dose; 322.3 µg·h/mL (90% CI,234.6 – 442.7) for high dose; and 214.6 µg·h/mL (90% CI, 176.2 – 261.2) for intravenous. High dose oral dosing achieved higher rifampicin exposure than intravenous: AUC0-∞ GMR 0.67 (90% CI, 0.46 −1.0); however, Cmax GMR was 1.11 (90% CI, 0.81 – 1.59), suggesting equivalence.ConclusionsPlasma rifampicin exposure was similar with high dose oral and intravenous administration. Findings support oral rifampicin dosing in future tuberculous meningitis trials.

BACKGROUND: Anti-TB drugs dosing based on weight alone may contribute to suboptimal drug concentrations and poor treatment outcomes in malnourished children. We examined the effect of malnutrition on the pharmacokinetics (PK) of first-line anti-TB drugs in children.METHODS: Drug concentrations were measured in Ghanaian children during the intensive phase of TB treatment. Weight-for-age (WFA), height-for-age (HFA), weight-for-height (WFH) and body mass index-for-age (BFA) were calculated and children with Z-scores < -2 SD (standard deviations) were considered as having malnutrition. PK differences of anti-TB drugs were compared by nutritional status.RESULTS: Of 100 participants, 24/48 (50.0%) of those younger than 5 years had wasting, 58/86 (67.4%) were underweight, and 56/99 (56.6%) had stunting; 22/51 (43.1%) children aged ≥5 years had low BFA. Children with stunting were more likely than controls to have lower mean peak concentration (Cmax) and area under the curve (AUC0–8h) of rifampin (RIF) and pyrazinamide (PZA), as well as a higher frequency of Cmax below the normal range. Wasting and underweight were associated with lower mean ethambutol (EMB) Cmax and AUC0–8h.CONCLUSIONS: The current WHO-recommended dosages were associated with lower plasma exposure of RIF, PZA and EMB in children with stunting, wasting and underweight. Anti-TB drugs dosing models for children may need to include height.

Contains fulltext : 244688.pdf (Publisher’s version ) (Open Access) Bedaquiline is recommended for the treatment of all patients with rifampin-resistant tuberculosis (RR-TB). Bedaquiline accumulates within cells, but its intracellular pharmacokinetics have not been characterized, which may have implications for dose optimization. We developed a novel assay using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure the intracellular concentrations of bedaquiline and its primary metabolite M2 in patients with RR-TB in South Africa. Twenty-one participants were enrolled and underwent sparse sampling of plasma and peripheral blood mononuclear cells (PBMCs) at months 1, 2, and 6 of treatment and at 3 and 6 months after bedaquiline treatment completion. Intensive sampling was performed at month 2. We used noncompartmental analysis to describe plasma and intracellular exposures and a population pharmacokinetic model to explore the relationship between plasma and intracellular pharmacokinetics and the effects of key covariates. Bedaquiline concentrations from month 1 to month 6 of treatment ranged from 94.7 to 2,540 ng/ml in plasma and 16.2 to 5,478 ng/ml in PBMCs, and concentrations of M2 over the 6-month treatment period ranged from 34.3 to 496 ng/ml in plasma and 109.2 to 16,764 ng/ml in PBMCs. Plasma concentrations of bedaquiline were higher than those of M2, but intracellular concentrations of M2 were considerably higher than those of bedaquiline. In the pharmacokinetic modeling, we estimated a linear increase in the intracellular-plasma accumulation ratio for bedaquiline and M2, reaching maximum effect after 2 months of treatment. The typical intracellular-plasma ratios 1 and 2 months after start of treatment were 0.61 (95% confidence interval [CI]: 0.42 to 0.92) and 1.10 (95% CI: 0.74 to 1.63) for bedaquiline and 12.4 (95% CI: 8.8 to 17.8) and 22.2 (95% CI: 15.6 to 32.3) for M2. The intracellular-plasma ratios for both bedaquiline and M2 were decreased by 54% (95% CI: 24 to 72%) in HIV-positive patients compared to HIV-negative patients. Bedaquiline and M2 were detectable in PBMCs 6 months after treatment discontinuation. M2 accumulated at higher concentrations intracellularly than bedaquiline, supporting in vitro evidence that M2 is the main inducer of phospholipidosis.

Background: Conflicting evidence obscures the role of partnerships with older men in the HIV epidemic in adolescent girls and young women (AGYW, aged 15-24) in sub-Saharan Africa. We assessed the effect of partner age and potential mediators on AGYW HIV infection using data from Population-based HIV Impact Assessments in Eswatini, Lesotho, Malawi, Namibia, Tanzania, Uganda, Zambia, and Zimbabwe. Methods: PHIA surveys collect data on HIV-related outcomes. Recent infection was estimated using an HIV-1 LAg avidity assay algorithm. We examined the association between reported partner age and recent AGYW HIV infection, incorporating population-level HIV prevalence and viremia from the reported male age-band. Logistic regression analyses compared the odds of recent infection in AGYW with older male partners to those reporting same-age male partner, adjusting for AGYW age, country, and urban/rural residence. Dyadic analysis examined observed cohabitating partner age, HIV status, and viremia to assess associations with recent and prevalent infection in their AGYW spouses. Findings: Among 17,813 AGYW, increasing reported partner age was associated with higher odds of recent infection, with the highest odds for partners aged 35-44 years (adjusted odds ratio (aOR) 8·94, 95% CI 2·63-30·37) compared to partners aged 15-24. Population-level viremia was highest in this male age-band. Dyadic analyses of 5,432 partnerships confirmed the association between partner age-band of 35-44 and prevalent HIV infection (aOR 3·82, 95% CI 2·17-6·75). However, most new infections were in AGYW with partners aged 25-34, as the majority of AGYW had partners in this age-band. Interpretation: These results provide evidence that men aged 25-34 drive most AGYW infections, but partners over 9 years older than AGYW in the 35-44 age-band confer greater risk. Population-level infectiousness and male age should be incorporated into identifying high-risk typologies. Funding Information: This research publication has been supported by the President's Emergency Plan for AIDS Relief (PEPFAR) through the US Centers for Disease Control and Prevention (CDC) under the terms of cooperative agreements U2GGH001226 and U2GGH001271. Joanne Mantell and Susie Hoffman were supported by a NIMH Center Grant P30-MH43520 (Principal Investigator: Robert H. Remien, PhD). The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the funding agencies. Declaration of Interests: Authors declare that they have no competing interests. Ethics Approval Statement: A guardian or parent provided permission for interviewers to approach 10-17-year-olds who then assented. Informed consent/assent was documented via electronic signature, with witnesses verifying consent for illiterate individuals The PHIA protocols were approved by national ethics committees, and the institutional review boards at Columbia University Irving Medical Center, the University of California in San Francisco for Namibia, and the US Centers for Disease Control and Prevention.

Background: No evidence-based dosing guidance is available for abacavir (ABC) liquid formulation use from birth. Newly available ABC pharmacokinetic (PK) data from neonates and immature infants were used to determine the optimal ABC dosing strategy (mg/kg) for infants 0-3 months and propose dosing per World Health Organization (WHO) weight-bands for neonates. Methods: Abacavir PK and safety data were pooled from three studies: (1) PACTG 321 (2) the Tygerberg Cohort and (3) IMPAACT P1106. Studies 1 and 2 were performed in neonates exposed to HIV receiving a single dose of ABC. Study 3 included predominantly low birth weight (LBW

Background: Cycloserine, or its structural analogue terizidone, has been associated with neuropsychiatric toxicity (psychosis, depression, and neuropathy). Prospective clinical data on the incidence of and risk factors for neuropsychiatric toxicity in TB patients treated with cycloserine are limited. Methods: A prospective evaluation of neuropsychiatric toxicity was performed using validated screening tools in patients with multidrug-resistant tuberculosis treated with terizidone. Cox proportional hazard modelling was performed to explore the effects of clinical variables and measures of cycloserine pharmacokinetics in plasma. Results: A total 144 participants were recruited: 86 were male and 58 were female; their median age was 35.7 years and 91 (63%) were HIV-infected. Fifty-five (38%) participants developed at least one neuropsychiatric event (30 cases per 100 person-months): 50 (35%) neuropathy, 14 (10%) depression, and 11 (8%) psychosis. Neuropathy was independently associated with cycloserine clearance ((adjusted hazard ratio 0.34 (aHR), P = 0.03)) and high-dose pyridoxine (200 mg vs 150 mg daily, aHR: 2.79, P = 0.01). Conclusions: A high incidence of early neuropsychiatric toxicity was observed in this cohort of patients treated with terizidone. Cycloserine clearance and higher doses of pyridoxine are associated with incident or worsening peripheral neuropathy.

Evidence on the relationship between lifestyle, socio-economic factors and pesticide exposure and urinary concentrations of organophosphate (OP) pesticide metabolites among children is generally incomplete. This study investigated the relationship between socio-economic factors and reported pesticide exposures and the sum of three urinary concentrations of dialkyl phosphate metabolites (DAP) among boys living in the rural areas of the Western Cape, South Africa. Data was collected during a cross-sectional study of 183 boys from three agricultural intense areas. Measurements included a questionnaire on socio-economic and pesticide exposures and urinary DAP concentrations. Most boys (70%) lived on farms with a median age of 12 years (range: 5.0–19.5 years). Children aged >14 years had lower DAP urine concentrations (median = 39.9 ng/ml; β = −68.1 ng/ml; 95% CI: −136.8, 0.6) than children aged 9 years and younger (median = 107.0 ng/ml). DAP concentrations also varied significantly with area, with concentrations in the grape farming area, Hex River Valley (median = 61.8 ng/ml; β = −52.1; 95% CI: −97.9, −6.3 ng/ml) and the wheat farming area, Piketberg (median = 72.4 ng/ml; β = −54.2; 95% CI: 98.8, −9.7 ng/ml) lower than those in the pome farming area, Grabouw (median = 79.9 ng/ml). Other weaker and non-significant associations with increased DAP levels were found with increased household income, member of household working with pesticides, living on a farm, drinking water from an open water source and eating crops from the vineyard and or garden. The study found younger age and living in and around apple and grape farms to be associated with increased urinary DAP concentrations. Additionally, there were other pesticide exposures and socio-economic and lifestyle factors that were weakly associated with elevated urinary DAP levels requiring further study. The study provided more evidence on factors associated to urinary DAP concentrations especially in developing country settings.

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor that is used in the treatment of human immunodeficiency virus (HIV) infection in children younger than 3 years old. Identifying genetic predictors of NVP pharmacokinetics (PK) in young children is important because inter-individual variability in NVP concentrations contributes to variable treatment response and the information may be used to individualize dosing decisions. We examined the relationship between genetic variations in relevant drug disposition genes and NVP PK parameters in Ghanaian children living with HIV eligible to initiate NVP-based antiretroviral therapy. Participants received NVP plus zidovudine and lamivudine or abacavir and lamivudine twice daily, and those with tuberculosis (TB) coinfection received concurrent anti-TB therapy with NVP. Pharmacokinetic sampling was performed after at least 4 weeks of antiretroviral therapy. Nevirapine minimum concentration (Cmin), area under the concentration-time curve from time 0 to 12 h (AUC0–12h), and apparent clearance (CL/F) were calculated using non-compartmental analysis using Phoenix v8.0 software. Genotyping for CYP2B6, CYP2A6, CYP3A5, ABCB1, NR1I2, and NR1I3 single nucleotide polymorphism (SNPs) was performed by TaqMan® allelic discrimination method. The median (range) NVP dose received was 10 (7–14) mg/kg. Of the 53 participants, the median (range) Cmin was 3.3 (0.0–14.0) mg/L and AUC0–12h was 56.0 (16.7–202.6) mg.hr/L. Using step-wise regression, CYP2B6 rs3745274 and NR1I2 rs6785049 SNPs were independent as well as joint predictors of NVP AUC0–12h, Cmin, and CL/F. We concluded that genotyping for CYP2B6 rs3745274, and the NR1I2 rs6785049 G > A SNP (which encodes the transcriptional factor, pregnane X receptor), could improve prediction of NVP PK for individualized therapy.

Summary Background HIV incidence among adolescents in southern Africa remains unacceptably high. Pre-exposure prophylaxis (PrEP) is an effective HIV prevention intervention but there are few data on its implementation among adolescents. We aimed to investigate the safety, feasibility, and acceptability of PrEP with oral tenofovir disoproxil fumarate and emtricitabine as part of a comprehensive HIV prevention package in an adolescent population in South Africa. Methods This open-label single-arm phase 2 study (PlusPills) was done in two research clinics in Cape Town and Johannesburg, South Africa. Adolescents aged 15-19 years were recruited into the study through recruitment events and outreach in the community. Potential participants were eligible for enrolment if they reported being sexually active. Exclusion criteria were a positive test for HIV or pregnancy at enrolment, breastfeeding, or any relevant co-morbidities. Participants were given oral tenofovir disoproxil fumarate and emtricitabine for PrEP to take daily for the first 12 weeks and were then given the choice to opt in or out of PrEP use at three monthly intervals during scheduled clinic visits. Participants were invited to monthly visits for adherence counselling and HIV testing during the study period. The primary outcomes were acceptability, use, and safety of PrEP. Acceptability was measured by the proportion of participants who reported willingness to take up PrEP and remain on PrEP at each study timepoint. Use was defined as the number of participants who continued to use PrEP after the initial 12-week period until the end of the study (week 48). Safety was measured by grade 2, 3, and 4 laboratory and clinical adverse events using the Division of AIDS table for grading the severity of adult and paediatric adverse events, version 1.0. Dried blood spot samples were collected at each study time-point to measure tenofovir diphosphate concentrations. This trial is registered with ClinicalTrials.gov , NCT02213328 . Findings Between April 28, 2015, and Nov 11, 2016, 244 participants were screened, and 148 participants were enrolled (median age was 18 years; 99 participants [67%] were female) and initiated PrEP. PrEP was stopped by 26 of the 148 (18%) participants at 12 weeks. Cumulative PrEP opt-out, from the total cohort, was 41% (60 of 148 participants) at week 24 and 43% (63 of 148 participants) at week 36. PrEP was well tolerated with only minor adverse events (grade 2) thought to be related to study drug, which included headache (n=4, 3%), gastrointestinal upset (n=8, 5%), and skin rash (n=2, 1%). Two participants (1%) experienced grade 3 weight loss, which was deemed related to the study drug and resolved fully when PrEP was discontinued. Tenofovir diphosphate concentrations were detectable (>16 fmol/punch) in dried blood spot samples in 108 (92%) of 118 participants who reported PrEP use at week 12, in 74 (74%) of 100 participants at week 24, and in 22 (59%) of 37 participants by the study end at week 48. Interpretation In this cohort of self-selected South African adolescents at risk of HIV acquisition, PrEP appears safe and tolerable in those who continued use. PrEP use decreased throughout the course of the study as the number of planned study visits declined. Adolescents in southern Africa needs access to PrEP with tailored adherence support and possibly the option for more frequent and flexible visit schedules. Funding National Institute of Allergy and Infectious Diseases of the US National Institutes of Health.

Background Treatment options are limited for TB/HIV-coinfected children who require PI-based ART. Rifabutin is the preferred rifamycin for adults on PIs, but the one study evaluating rifabutin with PIs among children was stopped early due to severe neutropenia. Methods We evaluated rifabutin safety and plasma pharmacokinetics among coinfected children 3–15 years of age receiving rifabutin 2.5 mg/kg daily with standard doses of lopinavir/ritonavir. The AUC0–24 at 2, 4 and 8 weeks after rifabutin initiation was described using intensive sampling and non-compartmental analysis. Clinical and laboratory toxicities were intensively monitored at 12 visits throughout the study. Results Among 15 children with median (IQR) age 13.1 (10.9–14.0) years and weight 25.5 (22.3–30.5) kg, the median (IQR) rifabutin AUC0–24 was 5.21 (4.38–6.60) μg·h/mL. Four participants had AUC0–24 below 3.8 μg·h/mL (a target for the population average exposure) at week 2 and all had AUC0–24 higher than 3.8 μg·h/mL at the 4 and 8 week visits. Of 506 laboratory evaluations during rifabutin, grade 3 and grade 4 abnormalities occurred in 16 (3%) and 2 (0.4%) instances, respectively, involving 9 (60%) children. Specifically, grade 3 (n = 4) and grade 4 (n = 1) neutropenia resolved without treatment interruption or clinical sequelae in all patients. One child died at week 4 of HIV-related complications. Conclusions In children, rifabutin 2.5 mg/kg daily achieved AUC0–24 comparable to adults and favourable HIV and TB treatment outcomes were observed. Severe neutropenia was relatively uncommon and improved with ongoing rifabutin therapy. These data support the use of rifabutin for TB/HIV-coinfected children who require lopinavir/ritonavir.