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ObjectivesTenofovir disoproxil fumarate (TDF) is increasingly used in the highly active antiretroviral therapy (HAART) regimens of pregnant women, but limited data exist on the pregnancy pharmacokinetics of chronically dosed TDF. This study described tenofovir pharmacokinetics during pregnancy and postpartum.MethodsInternational Maternal Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) P1026s is a prospective, nonblinded pharmacokinetic study of HIV-infected pregnant women that included a cohort receiving 300 mg TDF once daily. Steady-state 24-hour pharmacokinetic profiles were measured at the second and third trimesters, postpartum, and in maternal and umbilical cord samples collected at delivery. Tenofovir was measured by liquid chromatography-mass spectrometry (LC-MS). The target area under the concentration versus time curve from time 0 to 24 h post dose (AUC) was ≥ 1.99 μg h/mL (nonpregnant historical control 10th percentile).ResultsThe median tenofovir AUC was decreased during the second (1.9 μg h/mL) and third (2.4 μg h/mL; P = 0.005) trimesters versus postpartum (3.0 μg h/mL). Tenofovir AUC exceeded the target for two of four women (50%) in the second trimester, 27 of 37 women [73%; 95% confidence interval (CI) 56%, 86%] in the third trimester, and 27 of 32 women (84%; 95% CI 67%, 95%) postpartum (P > 0.05). Median second/third-trimester troughs were lower (39/54 ng/mL) than postpartum (61 ng/mL). Median third-trimester weight was greater for subjects below the target AUC versus those above the target (97.9 versus 74.2 kg, respectively; P = 0.006). The median ratio of cord blood to maternal concentrations was 0.88. No infants were HIV infected.ConclusionsThis study found lower tenofovir AUC and troughs during pregnancy. Transplacental passage with chronic TDF use during pregnancy was high. Standard TDF doses appear to be appropriate for most HIV-infected pregnant women but therapeutic drug monitoring with dose adjustment should be considered in pregnant women with high weight (> 90 kg) or inadequate HIV RNA response.

ObjectivesTenofovir disoproxil fumarate (TDF) is increasingly used in the highly active antiretroviral therapy (HAART) regimens of pregnant women, but limited data exist on the pregnancy pharmacokinetics of chronically dosed TDF. This study described tenofovir pharmacokinetics during pregnancy and postpartum.MethodsInternational Maternal Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) P1026s is a prospective, nonblinded pharmacokinetic study of HIV-infected pregnant women that included a cohort receiving 300 mg TDF once daily. Steady-state 24-hour pharmacokinetic profiles were measured at the second and third trimesters, postpartum, and in maternal and umbilical cord samples collected at delivery. Tenofovir was measured by liquid chromatography-mass spectrometry (LC-MS). The target area under the concentration versus time curve from time 0 to 24 h post dose (AUC) was ≥ 1.99 μg h/mL (nonpregnant historical control 10th percentile).ResultsThe median tenofovir AUC was decreased during the second (1.9 μg h/mL) and third (2.4 μg h/mL; P = 0.005) trimesters versus postpartum (3.0 μg h/mL). Tenofovir AUC exceeded the target for two of four women (50%) in the second trimester, 27 of 37 women [73%; 95% confidence interval (CI) 56%, 86%] in the third trimester, and 27 of 32 women (84%; 95% CI 67%, 95%) postpartum (P > 0.05). Median second/third-trimester troughs were lower (39/54 ng/mL) than postpartum (61 ng/mL). Median third-trimester weight was greater for subjects below the target AUC versus those above the target (97.9 versus 74.2 kg, respectively; P = 0.006). The median ratio of cord blood to maternal concentrations was 0.88. No infants were HIV infected.ConclusionsThis study found lower tenofovir AUC and troughs during pregnancy. Transplacental passage with chronic TDF use during pregnancy was high. Standard TDF doses appear to be appropriate for most HIV-infected pregnant women but therapeutic drug monitoring with dose adjustment should be considered in pregnant women with high weight (> 90 kg) or inadequate HIV RNA response.

ObjectivesPregnancy results in physiological changes altering the pharmacokinetics of drugs metabolized by cytochrome P450 3A4 (CYP3A4). The urinary ratio of 6-β hydroxycortisol to cortisol (6βHF : F) is a marker of CYP3A4 induction. We sought to evaluate its change in antiretroviral (ARV)-treated HIV-1-infected women and to relate this change to ARV pharmacokinetics.MethodsWomen receiving various ARVs had pharmacokinetic evaluations during the third trimester of pregnancy (>30 weeks) and postpartum with determination of 6βHF : F carried out on the same days. The Wilcoxon signed rank test was used to compare the ratio antepartum to postpartum. The relationship between the change in ratio and the change in pharmacokinetics was analysed using Kendall's tau.Results6βHF : F ratios were available for 107 women antepartum, with 54 having postpartum values. The ratio was higher antepartum (P=0.033) (median comparison 1.35; 95% confidence interval 1.01, 1.81). For 71 women taking a protease inhibitor (PI), the antepartum vs. postpartum 6βHF : F comparison was marginally significant (P=0.058). When the change in the 6βHF : F ratio was related to the change in the dose-adjusted ARV area under the plasma concentration vs. time curve (AUC) between antepartum and postpartum, the 35 subjects in the lopinavir/ritonavir (LPV/r) arms demonstrated an inverse relationship (P=0.125), albeit this correlation did not reach statistical significance.ConclusionsA 35% increase in the urinary 6βHF : F ratio was measured during late pregnancy compared with postpartum, indicating that CYP3A induction occurs during pregnancy. The trend towards an inverse relationship between the change in the 6βHF : F ratio and the change in the LPV AUC antepartum vs. postpartum suggests that CYP3A induction may be one mechanism behind altered LPV exposure during pregnancy.

OBJECTIVE: We evaluated the pharmacokinetics (pk) of raltegravir in HIV-infected women during pregnancy and postpartum. METHODS: IMPAACT 1026s is an on-going prospective study of antiretroviral pk during pregnancy (NCT00042289). Women receiving 400 mg raltegravir twice daily in combination antiretroviral therapy had intensive steady state 12-hour pk profiles performed during pregnancy and at 6-12 weeks postpartum. Targets were trough concentration above 0.035 μg/mL, the estimated tenth percentile in non-pregnant historical controls. RESULTS: Median raltegravir AUC was 6.6 μg*hr/mL for second trimester (n= 16), 5.4 μg*hr/mL for third trimester (n=41), and 11.6 μg*hr/mL postpartum (n= 38) (p=0.03 pp vs 2 trimester, p=0.001 pp vs third trimester). Trough concentrations were above the target in 69%, 80%, and 79% of second trimester, third trimester and postpartum subjects respectively, with wide variability ( < 0.010-0.917 μg/mL), and no significant difference between third trimester and postpartum trough concentrations was detected. The median ratio of cord blood/maternal raltegravir concentrations was 1.5. HIV RNA levels were < 400 copies/mL in 92% of women at delivery. Adverse events included elevated liver transaminases in one woman and vomiting in one. All infants with known status are HIV-uninfected. CONCLUSIONS: Median raltegravir AUC was reduced by approximately 50% during pregnancy; trough concentrations were frequently below target both during late pregnancy and postpartum. Raltegravir readily crossed the placenta. High rates of viral suppression at delivery and the lack of a clear relationship between raltegravir concentration and virologic effect in nonpregnant adults suggest that despite the decreased exposure during pregnancy, a higher dose is not necessary.

Objectives Pregnancy results in physiological changes altering the pharmacokinetics of drugs metabolized by cytochrome P450 3 A4 ( CYP3A4). The urinary ratio of 6-β hydroxycortisol to cortisol ( 6βHF : F) is a marker of CYP3A4 induction. We sought to evaluate its change in antiretroviral ( ARV)-treated HIV-1-infected women and to relate this change to ARV pharmacokinetics. Methods Women receiving various ARVs had pharmacokinetic evaluations during the third trimester of pregnancy (> 30 weeks) and postpartum with determination of 6β HF : F carried out on the same days. The Wilcoxon signed rank test was used to compare the ratio antepartum to postpartum. The relationship between the change in ratio and the change in pharmacokinetics was analysed using Kendall's tau. Results 6βHF : F ratios were available for 107 women antepartum, with 54 having postpartum values. The ratio was higher antepartum ( P = 0.033) (median comparison 1.35; 95% confidence interval 1.01, 1.81). For 71 women taking a protease inhibitor (PI), the antepartum vs. postpartum 6β HF : F comparison was marginally significant ( P = 0.058). When the change in the 6β HF : F ratio was related to the change in the dose-adjusted ARV area under the plasma concentration vs. time curve ( AUC) between antepartum and postpartum, the 35 subjects in the lopinavir/ritonavir ( LPV/r) arms demonstrated an inverse relationship ( P = 0.125), albeit this correlation did not reach statistical significance. Conclusions A 35% increase in the urinary 6β HF : F ratio was measured during late pregnancy compared with postpartum, indicating that CYP3A induction occurs during pregnancy. The trend towards an inverse relationship between the change in the 6β HF : F ratio and the change in the LPV AUC antepartum vs. postpartum suggests that CYP3A induction may be one mechanism behind altered LPV exposure during pregnancy. [ABSTRACT FROM AUTHOR]

Objective: To investigate the safety, tolerability, and pharmacokinetics of the anti-tumor necrosis factor-alpha monoclonal antibody infliximab in subjects with intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD).Study Design: We conducted a multicenter, randomized, prospective trial of second IVIG infusion (2 g/kg) versus infliximab (5 mg/kg) in 24 children with acute KD and fever after initial treatment with IVIG. Primary outcome measures were the safety, tolerability, and pharmacokinetics of infliximab. Secondary outcome measures were duration of fever and changes in markers of inflammation.Results: Study drug infusions were associated with cessation of fever within 24 hours in 11 of 12 subjects treated with infliximab and in 8 of 12 subjects retreated with IVIG. No infusion reactions or serious adverse events were attributed to either study drug. No significant differences were observed between treatment groups in the change from baseline for laboratory variables, fever, or echocardiographic assessment of coronary arteries.Conclusions: Both infliximab and a second IVIG infusion were safe and well tolerated in the subjects with KD who were resistant to standard IVIG treatment. The optimal management of patients resistant to IVIG remains to be determined. [ABSTRACT FROM AUTHOR]

This study assessed the single- and multiple-dose pharmacokinetics of 3 doses (15 mg, 30 mg, and 45 mg) of pioglitazone in 36 adolescents with type 2 diabetes. Blood samples were obtained over a 48-hour interval after the first dose (day 1) and over a 72-hour interval after the last dose (day 15) of pioglitazone and were assayed for pioglitazone and active metabolites (M-III and M-IV). Pioglitazone systemic exposure increased dose dependently but was less than dose proportional during multiple dosing. The median peak pioglitazone concentration occurred at 2 hours. The mean half-life was 8 to 9 hours for pioglitazone and 24 to 32 hours for M-III and M-IV, with similar values at each dose level. During multiple dosing, accumulation for pioglitazone was negligible, but it reached 2.5- to 3.0-fold for M-III and M-IV. The sustained total serum concentration of active compounds during multiple dosing provides the basis for once-daily dose administration of pioglitazone in adolescents. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the population pharmacokinetics (PK) and pharmacodynamics (PD) of zidovudine (ZDV) in infants and children. This evaluation includes 394 subjects who participated in Pediatric AIDS Clinical Trials Group (PACTG) Study 152 and received either ZDV alone or in combination with didanosine. The most significant PK covariate was age, with infants < 2 years of age having reduced size-adjusted clearance. ZDV exposure was weakly related to maximal reduction in immune complex-dissociated (ICD) p24 antigen but not to reduction at 6 months. Mild chronic anemia occurred in 7.6% of subjects with ZDV average concentration < 1.3 microM (350 ng/mL) versus in 23.4% subjects with higher ZDV concentrations (p < 0.001). There was a direct linear relationship between hemoglobin and ZDV levels. It was concluded that ZDV oral clearance is reduced in infants compared to older children. This lower clearance leads to higher ZDV exposure in infants and contributes to increased hematologic toxicity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to describe the maturation of vancomycin (V) clearance and the influence of altered renal function in infants on vancomycin using population pharmacokinetic methods. A population pharmacokinetic model was developed using NONMEM from clinical data obtained from 374 newborns and infants < 2 years of age (median age = 27 days) from four institutions. A total of 1103 serum V concentrations were used in the model development, including 311 with elevated serum creatinine (CR) (> 0.8 mg/dl) and more than 104 evaluations in infants older than 2 months of age. The final model was evaluated against a second data set of 160 concentrations from 67 infants at one of the institutions and then used to develop dosing guidelines. The data were best described by a two-compartment model. Weight and CR greatly influenced vancomycin elimination, while postnatal age and prematurity (< 28 weeks) were significant but less important predictors of V elimination. For the typical study infant (age = 27 days, CR = 0.6, WT= 1.8 kg, gestational age = 33.5 weeks), this results in VdSS = 0.79 l/kg and Cl = 0.066 l/h/kg. The validation data set showed the model to be unbiased. Dosing guidelines from this model, based on serum creatinine and gestational age at birth, performed better than published guidelines based on postconceptional age. Vancomycin clearance is initially reduced in premature infants and increases with postnatal age. Most of the age-related changes could be predicted by the concomitant fall in serum creatinine. Dosing guidelines that incorporate these factors are more likely to produce therapeutic V concentrations in infants. [ABSTRACT FROM AUTHOR]

Dichloroacetate (DCA) is a small molecule that reduces ambient concentrations of lactate in man. It was the purpose of this study to develop pharmacokinetic and pharmacodynamic models for determination of a dose for a pivotal Phase III clinical trial of DCA in patients with traumatic brain injury (TBI). Population pharmacokinetic and pharmacodynamic models were developed for DCA using NONMEM software. The pharmacokinetic data were fit to a physiologic two-compartment model, and the pharmacodynamic data were fit to an indirect physiologic response model. Simulations were employed to evaluate various dosing strategies for consideration in a pivotal Phase III clinical trial of DCA. For the pharmacokinetic model, it was discovered that the clearance of DCA decreased on multiple dosing from 4.82 L/h to 1.07 L/h and that the pharmacokinetics and pharmacodynamics in TBI patients could not be predicted from normal volunteers. Population pharmacokinetic modeling and simulation of the expected effects of several dosing strategies were useful procedures for designing a Phase III trial. [ABSTRACT FROM AUTHOR]

Background: In infants and children, treatment of Kawasaki disease (KD) with high-dose intravenous immunoglobulin (IVIG) and acetylsalicylic acid ([ASA] aspirin) diminishes inflammatory response and reduces the risk for coronary artery abnormalities. However, patients with high serum concentrations of tumor necrosis factor (TNF)-alpha, which is associated with vascular damage, may develop coronary artery lesions even with treatment. The hemorheologic agent pentoxifylline blocks the production of TNF-alpha and may be an appropriate adjunctive therapy to IVIG and ASA.Objective: The objective of this study was to assess the pharmacokinetic characteristics and tolerability of a new oral syrup formulation of pentoxifylline as an adjunct to IVIG and ASA in the treatment of KD in children.Methods: Hospitalized boys and girls aged 6 months to 5 years and who were diagnosed with KD within the first 10 days of illness were eligible. Patients were assigned to 1 of 4 pentoxifylline treatment groups, by dose level (dose levels 1, 2, 3, and 4: 10, 15, 20, and 25 mg/kg daily, respectively, divided into 3 doses). Six plasma samples collected at the time the first dose was administered, and 4 samples collected after administration of the last dose on study day 6, were assessed by high-performance liquid chromatography using noncompartmental and 1-compartment pharmacokinetic analyses for pentoxifylline and its active metabolite (M-1). TNF-alpha levels on days 1 and 6 were assessed using electroimmunoassay.Results: Fourteen boys and 10 girls were enrolled. The mean age, body weight, and illness day at study entry were 34.5 months, 13.8 kg, and 6, respectively. Pentoxifylline exhibited nonlinear kinetic characteristics, with median area under the plasma concentration-time curve from time 0 to infinity(AUC0[symbol: see text) values of 622, 3428, 8416, and 10,347 ng/mL x h for dose levels 1 to 4, respectively, on study day 1. Pentoxifylline noncompartmental oral clearance and volume of distribution were significantly lower, and dose-normalized AUC0[symbol:see text] was significantly higher, for dose level 3 than dose level 1. M-1 parameters were not significantly different between dose levels. No accumulation of pentoxifylline or M-1 was noted. Fifteen of 24 patients (63%) reported mild to moderate adverse events that may or may not have been treatment related. Frequency and severity did not differ significantly between dose levels.Conclusions: In the children in this study, pentoxifylline was well tolerated at the doses studied. No notable differences in clinical outcomes were observed between dose levels, and dose levels 3 and 4 (20 and 25 mg/kg daily, respectively) resulted in similar exposure to both pentoxifylline and M-1. Future efficacy and tolerability studies should use a daily dose of 20 mg/kg of pentoxifylline in acute KD. [ABSTRACT FROM AUTHOR]

Objectives: To develop a pragmatic twice daily lamivudine dosing strategy for preterm infants from 24 to 37 completed weeks of gestation., Methods: Data were combined from eight pharmacokinetic studies in neonates and infants receiving lamivudine oral solution. A population pharmacokinetic model was developed using non-linear mixed effects regression. Different lamivudine dosing strategies, stratified by gestational age at birth (GA) bands, were simulated in a virtual population of preterm infants, aimed at maintaining lamivudine drug exposures (AUC0-12) within a reference target range of 2.95 to 13.25 µg·h/mL, prior to switching to WHO-weight band doses when ≥4 weeks of age and weighing ≥3 kg., Results: A total of 154 infants (59% female) contributed 858 lamivudine plasma concentrations. Median (range) GA at birth was 38 (27-41) weeks. At the time of first pharmacokinetic sampling infants were older with median postnatal age (PNA) of 6.3 (0.52-26.6) weeks. Lamivudine concentrations were described by a one-compartment model, with CL/F and V/F allometrically scaled to weight. Maturation of CL/F was described using an Emax model based on PNA. CL/F was also adjusted on GA to allow extrapolation for extreme prematurity. Simulations predicted an optimal lamivudine dosing for infants GA ≥24 to <30 weeks of 2 mg/kg twice daily from birth until weighing 3 kg; and for GA ≥30 to <37 weeks, 2 mg/kg twice daily for the first 4 weeks of life, followed by 4 mg/kg twice daily until weighing 3 kg., Conclusions: Model-based predictions support twice daily pragmatic GA band dosing of lamivudine for preterm infants, but clinical validation is warranted., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: To confirm that levetiracetam (LEV) demonstrates predictable pharmacokinetics(PK) at higher doses and to study the pharmacodynamics(PD) of LEV., Design: Pharmacokinetic data from the NEOLEV1 and NEOLEV2 trials were analysed using a non-linear mixed effects modelling approach. A post hoc analysis of the effect of LEV on seizure burden was conducted., Setting: Neonatal intensive care unit., Patients: Term neonates with electrographically confirmed seizures., Interventions: In NEOLEV1, neonates with seizures persisting following phenobarbital (PHB) received LEV 20 or 40 mg/kg bolus followed by 5 or 10 mg/kg maintenance dose(MD) daily. In NEOLEV2, patients received a 40 mg/kg intravenous LEV load, followed by 10 mg/kg doses 8 hourly. If seizures persisted, a further 20 mg/kg intravenous load was given. If seizures persisted, PHB was given. PK data were collected from 16 NEOLEV1 patients and 33 NEOLEV2 patients. cEEG data from 48 NEOLEV2 patients were analysed to investigate onset of action and seizure burden reduction., Main Outcome Measures: Clearance (CL) and volume of distribution (V d ) were determined. Covariates that significantly affected LEV disposition were identified., Results: Primary outcome: The median initial LEV level was 57 µg/mL (range 19-107) after the first loading dose and at least 12 µg/mL at 48 hours in all infants. CL and V d were estimated to be 0.0538 L/hour and 0.832 L, respectively. A direct relationship between postnatal age and CL was observed. The final population pharmacokinetic(PopPK) model described the observed data well without significant biases. CL and V d were described as CL (L/hour)=0.0538×(weight in kg/3.34)0.75×(postnatal age in days/5.5) 0.402 and V d (L)=0.832×(weight in kg/3.34).Seizure burden reduced within 30 min of LEV administration. 28% of patients were completely seizure free after LEV. In an additional 25% of patients, seizure burden reduced by 50%., Conclusions: LEV pharmacokinetics remained predictable at higher doses. Very high-dose LEV can now be studied in neonates., Trial Registration Number: NCT01720667., Competing Interests: Competing interests: RHH and CS have done consulting work for Sparc pharmaceuticals who are seeking FDA indication for PHB in the treatment of neonatal seizures., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

BACKGROUNDBroadly neutralizing monoclonal antibodies (bNAbs) represent a promising strategy for HIV-1 immunoprophylaxis and treatment. 10E8VLS and VRC07-523LS are bNAbs that target the highly conserved membrane-proximal external region (MPER) and the CD4-binding site of the HIV-1 viral envelope glycoprotein, respectively.METHODSIn this phase 1, open-label trial, we evaluated the safety and pharmacokinetics of 5 mg/kg 10E8VLS administered alone, or concurrently with 5 mg/kg VRC07-523LS, via s.c. injection to healthy non-HIV-infected individuals.RESULTSEight participants received either 10E8VLS alone (n = 6) or 10E8VLS and VRC07-523LS in combination (n = 2). Five (n = 5 of 8, 62.5%) participants who received 10E8VLS experienced moderate local reactogenicity, and 1 participant (n = 1/8, 12.5%) experienced severe local reactogenicity. Further trial enrollment was stopped, and no participant received repeat dosing. All local reactogenicity resolved without sequelae. 10E8VLS retained its neutralizing capacity, and no functional anti-drug antibodies were detected; however, a serum t1/2 of 8.1 days was shorter than expected. Therefore, the trial was voluntarily stopped per sponsor decision (Vaccine Research Center, National Institute of Allergy and Infectious Diseases [NIAID], NIH). Mechanistic studies performed to investigate the underlying reason for the reactogenicity suggest that multiple mechanisms may have contributed, including antibody aggregation and upregulation of local inflammatory markers.CONCLUSION10E8VLS resulted in unexpected reactogenicity and a shorter t1/2 in comparison with previously tested bNAbs. These studies may facilitate identification of nonreactogenic second-generation MPER-targeting bNAbs, which could be an effective strategy for HIV-1 immunoprophylaxis and treatment.TRIAL REGISTRATIONClinicaltrials.gov, accession no. NCT03565315.FUNDINGDivision of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH.

Background: Combined intramuscular long-acting cabotegravir and long-acting rilpivirine constitute the first long-acting combination antiretroviral therapy (ART) regimen approved for adults with HIV. The goal of the IMPAACT 2017 study (MOCHA [More Options for Children and Adolescents]) was to assess the safety and pharmacokinetics of these drugs in adolescents., Methods: In this phase 1/2, multicentre, open-label, non-comparative, dose-finding study, virologically suppressed adolescents (aged 12-17 years; weight ≥35 kg; BMI ≤31·5 kg/m 2 ) with HIV-1 on daily oral ART were enrolled at 15 centres in four countries (Botswana, South Africa, Thailand, and the USA). After 4-6 weeks of oral cabotegravir (cohort 1C) or rilpivirine (cohort 1R), participants received intramuscular long-acting cabotegravir or long-acting rilpivirine every 4 weeks or 8 weeks per the adult dosing regimens, while continuing pre-study ART. The primary outcomes were assessments of safety measures, including all adverse events, until week 4 for oral cabotegravir and until week 16 for long-acting cabotegravir and long-acting rilpivirine, and pharmacokinetic measures, including the area under the plasma concentration versus time curve during the dosing interval (AUC 0-tau ) and drug concentrations, at week 2 for oral dosing of cabotegravir and at week 16 for intramuscular dosing of cabotegravir and rilpivirine. Enrolment into cohort 1C or cohort 1R was based on the participant's pre-study ART, meaning that masking was not done. For pharmacokinetic analyses, blood samples were drawn at weeks 2-4 after oral dosing and weeks 4-16 after intramuscular dosing. Safety outcome measures were summarised using frequencies, percentages, and exact 95% CIs; pharmacokinetic parameters were summarised using descriptive statistics. This trial is registered at ClinicalTrials.gov, NCT03497676, and is closed to enrolment., Findings: Between March 19, 2019, and Nov 25, 2021, 55 participants were enrolled: 30 in cohort 1C and 25 in cohort 1R. At week 16, 28 (97%, 95% CI 82-100) of the 29 dose-evaluable participants in cohort 1C and 21 (91%; 72-99) of the 23 dose-evaluable participants in cohort 1R had reported at least one adverse event, with the most common being injection-site pain (nine [31%] in cohort 1C; nine [39%] in cohort 1R; none were severe). One (4%, 95% CI 0-22) participant in cohort 1R had an adverse event of grade 3 or higher, leading to treatment discontinuation, which was defined as acute rilpivirine-related allergic reaction (self-limiting generalised urticaria) after the first oral dose. No deaths or life-threatening events occurred. In cohort 1C, the week 2 median cabotegravir AUC 0-tau was 148·5 (range 37·2-433·1) μg·h/mL. The week 16 median concentrations for the every-4-weeks and every-8-weeks dosing was 3·11 μg/mL (range 1·22-6·19) and 1·15 μg/mL (<0·025-5·29) for cabotegravir and 52·9 ng/mL (31·9-148·0) and 39·1 ng/mL (27·2-81·3) for rilpivirine, respectively. These concentrations were similar to those in adults., Interpretation: Study data support using long-acting cabotegravir or long-acting rilpivirine, given every 4 weeks or 8 weeks, per the adult dosing regimens, in virologically suppressed adolescents aged 12 years and older and weighing at least 35 kg., Funding: The National Institutes of Health and ViiV Healthcare., Competing Interests: Declaration of interests BMB, KB, PS, AHG, MAM, KC, and PO received IMPAACT Network grant funding from the National Institutes of Health (NIH) to support work on this protocol. AHG and PO's institutions have Clinical Trials Agreements (CTAs) with ViiV Healthcare to support the IMPAACT 2017 study. AHG's institution has a CTA with Janssen to support COVID-19 research and AHG is part of the ViiV Healthcare Pediatric Advisory Board. BMB, KB, MAM, SW, and RM's institution receives funding from ViiV Healthcare. MAM is a consultant for Bio-rad and receives royalties from Elsevier; their institution receives funding from Gilead for industry-sponsored research and funding from the NIH for HIV prevention and microbicide-related research. BMB's institution receives grant funding from Janssen for the study. HC, RMVS-R, and KV are employees of Janssen and have stock and stock options with Johnson & Johnson. ALA received grants or contracts from Gilead, Merck, and ViiV; and is content development faculty for the Simply Speaking HIV Prevention Series, an expert witness, an unpaid Advocates for Youth Board Chair, and an unpaid HIVMA Vice Chair. AC-G is a ViiV Healthcare consultant. CM and CMH are employees at ViiV Healthcare. SLF and JH are employees at GSK. SLF and CM own GSK stock or stock options. EVC is a Data Safety and Management Board member for a paediatric antibacterial study with Melinta Pharmaceuticals. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Study of liquid lopinavir/ritonavir (LPV/r) in young infants has been limited by concerns for its safety in neonates., Methods: International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1106 was a phase IV, prospective, trial evaluating the safety and pharmacokinetics of antiretroviral medications administered according to local guidelines to South African preterm and term infants <3 months of age. Safety evaluation through 24-week follow-up included clinical, cardiac and laboratory assessments. Pharmacokinetic data from P1106 were combined with data from International Maternal Pediatric Adolescent AIDS Clinical Trials Network studies P1030 and P1083 in a population pharmacokinetics model used to simulate LPV exposures with a weight-band dosing regimen in infants through age 6 months., Results: Safety and pharmacokinetics results were similar in 13/28 (46%) infants initiating LPV/r <42 weeks postmenstrual age (PMA) and in those starting ≥42 weeks PMA. LPV/r was started at a median (range) age of 47 (13-121) days. No grade 3 or higher adverse events were considered treatment related. Modeling and simulation predicted that for infants with gestational age ≥27 weeks who receive the weight-band dosing regimen, 82.6% will achieve LPV trough concentration above the target trough concentration of 1.0 µg/mL and 56.6% would exceed the observed adult lower limit of LPV exposure of 55.9 µg·h/mL through age 6 months., Conclusions: LPV/r oral solution was safely initiated in a relatively small sample size of infants ≥34 weeks PMA and >2 weeks of life. No serious drug-related safety signal was observed; however, adrenal function assessments were not performed. Weight-band dosing regimen in infants with gestational age ≥27 weeks is predicted to result in LPV exposures equivalent to those observed in other pediatric studies., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Existing solid antiretroviral fixed-dose combination formulations are preferred over liquid formulations in children, but their suitability for neonates is unknown. We evaluated the pharmacokinetics and safety of paediatric abacavir-lamivudine fixed-dose dispersible tablets and ritonavir-boosted lopinavir granules in neonates., Methods: In this open-label, two-stage, single-arm, phase 1/2, pharmacokinetic and safety trial, generic abacavir- lamivudine (120:60 mg) double-scored dispersible tablets and lopinavir boosted with ritonavir (40:10 mg) granules were studied. Neonates exposed to HIV (≥37 weeks gestational age) of no more than 3 days of age with birthweights of 2000-4000 g were identified through routine care in a tertiary hospital in Cape Town, South Africa. In stage 1, the pharmacokinetics and safety of two single doses were assessed to select the multidose strategy for stage 2. Neonates received a single dose of abacavir-lamivudine (30:15 mg, a quarter of a tablet) and lopinavir boosted with ritonavir (40:10 mg - one sachet) orally between 3 days and 14 days of age, and a second dose of a quarter tablet of abacavir-lamivudine and lopinavir boosted with ritonavir (80:20 mg, two sachets) 10-14 days later in stage 1. The multidose strategy selected in stage 2 was a quarter of the abacavir-lamivudine (30:15 mg) fixed-dose dispersible tablet once per day and two sachets of the lopinavir boosted with ritonavir (80:20 mg) granules twice per day from birth to age 28 days. In both stages two intensive pharmacokinetic visits were done, one at less than 14 days of life (pharmacokinetics 1) and another 10-14 days later (pharmacokinetics 2). Safety visits were done 1-2 weeks after each pharmacokinetic visit. Primary objectives were to assess pharmacokinetics and safety of abacavir, lamivudine, and lopinavir. Pharmacokinetic endpoints were area under the concentration time curve (AUC), maximum concentration, and concentration at end of dosing interval in all participants with at least one evaluable pharmacokinetic visit. Safety endpoints included grade 3 or worse adverse events, and grade 3 or worse treatment-related adverse events, occurring between study drug initiation and end of study. This completed trial is registered with the Pan African Clinical Trials Registry (PACTR202007806554538)., Findings: Between Aug 18, 2021, and Aug 18, 2022, 24 neonates were enrolled into the trial and received study drugs. Eight neonates completed stage 1, meeting interim pharmacokinetic and safety criteria. In stage 2, 16 neonates received study drugs. Geometric mean abacavir and lamivudine exposures (AUC 0-24 ) were higher at 6-14 days (51·7 mg × h/L for abacavir and 17·2 mg × h/L for lamivudine) than at 19-24 days of age (25·0 mg × h/L and 11·3 mg × h/L), whereas they were similar for lopinavir over this period (AUC 0-12 58·5 mg × h/L vs 46·4 mg × h/L). Abacavir geometric mean AUC0-24 crossed the upper reference range at pharmacokinetics 1, but rapidly decreased. Lamivudine and lopinavir AUC0-tau were within range. No grade 2 or worse adverse events were related to study drugs. One neonate had a grade 1 prolonged corrected QT interval using the Fridericia method that spontaneously resolved., Interpretation: Abacavir-lamivudine dispersible tablets and ritonavir-boosted lopinavir granules in neonates were safe and provided drug exposures similar to those in young infants. Although further safety data are needed, this regimen presents a new option for HIV prevention and treatment from birth. Accelerating neonatal pharmacokinetic studies of novel antiretroviral therapies is essential for neonates to also benefit from state-of-the-art treatments., Funding: Unitaid., Competing Interests: Declaration of interests All authors and their institutions received funding from Unitaid to do this study (except EVC). All authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Infants born with HIV-1 require lifelong antiretroviral therapy (ART). We aimed to assess whether very early ART in neonates might restrict HIV-1 reservoirs, an important step towards ART-free remission., Methods: IMPAACT P1115 is an ongoing, phase 1/2, proof-of-concept study in which infants were enrolled at 30 research clinics in 11 countries (Brazil, Haiti, Kenya, Malawi, South Africa, Tanzania, Thailand, Uganda, the USA, Zambia, and Zimbabwe) into two cohorts. Infants at least 34 weeks' gestational age at high risk for in-utero HIV-1 with either untreated maternal HIV-1 (cohort 1) or who were receiving pre-emptive triple antiretroviral prophylaxis outside of the study (maternal ART permissible; cohort 2) were included. All infants initiated treatment within 48 h of life. Cohort 1 initiated three-drug nevirapine-based ART, and cohort 2 initiated three-drug nevirapine-based prophylaxis then three-drug nevirapine-based ART following HIV diagnosis by age 10 days. We added twice-daily coformulated oral ritonavir 75 mg/m 2 and lopinavir 300 mg/m 2 from 14 days of life and 42 weeks postmenstrual age. We discontinued nevirapine 12 weeks after two consecutive plasma HIV-1 RNA levels below limit of detection. We tracked virological suppression, safety outcomes, and meeting a predetermined biomarker profile at age 2 years (undetectable RNA since week 48, HIV-1 antibody-negative, HIV-1 DNA not detected, and normal CD4 count and CD4 percentage) to assess qualification for analytical treatment interruption. This study is registered with ClinicalTrials.gov, NCT02140255., Findings: Between Jan 23, 2015, and Dec 14, 2017, 440 infants were included in cohort 1 and 20 were included in cohort 2. 54 of these infants (34 from cohort 1 and 20 from cohort 2) had confirmed in-utero HIV-1 and were enrolled to receive study ART. 33 (61%) of 54 infants were female and 21 (39%) were male. The estimated probability of maintaining undetectable plasma RNA through to 2 years was 33% (95% CI 17-49) in cohort 1 and 57% (28-78) in cohort 2. Among infants maintaining protocol-defined virological control criteria through to study week 108, seven of 11 (64%, 95% CI 31-89) in cohort 1 and five of seven (71%, 29-96) in cohort 2 had no detected HIV-1 DNA. Ten of 12 (83%, 52-100) in cohort 1 and all seven (100%, 59-100) in cohort 2 tested HIV-1 antibody-negative at week 108. Among 54 infants initiated on very early ART, ten (19%; six in cohort 1 and four in cohort 2) met all criteria for possible analytical treatment interruption. Reversible grade 3 or 4 adverse events occurred in 15 (44%) of 34 infants in cohort 1 and seven (35%) of 20 infants in cohort 2., Interpretation: Very early ART for in-utero HIV-1 can achieve sustained virological suppression in association with biomarkers indicating restricted HIV-1 reservoirs by age 2 years, which might enable potential ART-free remission., Funding: National Institute of Allergy and Infectious Diseases, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, and the National Institute of Mental Health., Competing Interests: Declaration of interests MM receives research support from Gilead Sciences, ViiV Healthcare, and Merck. EVC serves as a consultant to Melinta Pharmaceuticals. EGC's spouse holds an equity interest in AbbVie. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Clinical interpretation of the reduced dolutegravir (DTG) plasma concentrations reported during pregnancy is complicated by its high plasma protein binding. Plasma proteins significantly decrease during pregnancy, and understanding changes in DTG protein binding and its therapeutically active unbound concentrations are necessary to evaluate the impact of pregnancy changes on DTG pharmacokinetics., Methods: Retrospective assessment of plasma samples from pregnant women living with HIV enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s study receiving 50 mg DTG film-coated tablets once daily as part of clinical care. Unbound and total DTG concentrations were determined predose (C0) and at maximum (Cmax) concentrations during the second trimester (2T), third trimester (3T), and postpartum (PP). Percentage unbound was calculated as the ratio of ultrafiltrate unbound DTG concentration to total DTG concentration., Results: Twenty-nine mothers were included for protein binding evaluations; 15, 27, and 23 from the 2T, 3T, and PP, respectively. DTG % unbound for C0 and Cmax were significantly different by stage of pregnancy, with 3T significantly higher compared with PP; 1.02% vs. 0.69% (P = 0.0067) for C0 and 0.76% vs. 0.46% for Cmax (P = 0.0056). Median (IQR) unbound concentrations for C0 were 6.3 (4.7-18.4) for the 2T, 8.0 (5.6-16.9) for the 3T, and 13.3 (8.4-22.7) ng/mL PP, significantly different between 2T and PP (P = 0.0039), but not different between 3T and PP (P = 0.46)., Conclusion: Lower total DTG plasma concentrations during pregnancy coincide with temporal decreases in DTG protein binding, resulting in comparable unbound DTG concentrations during the 3T and PP., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Physiological changes during pregnancy may alter the pharmacokinetics (PK) of antituberculosis drugs. The International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s was a multicenter, phase IV, observational, prospective PK and safety study of antiretroviral and antituberculosis drugs administered as part of clinical care in pregnant persons living with and without HIV. We assessed the effects of pregnancy on rifampin, isoniazid, ethambutol, and pyrazinamide PK in pregnant and postpartum (PP) persons without HIV treated for drug-susceptible tuberculosis disease. Daily antituberculosis treatment was prescribed following World Health Organization-recommended weight-band dosing guidelines. Steady-state 12-hour PK profiles of rifampin, isoniazid, ethambutol, and pyrazinamide were performed during second trimester (2T), third trimester (3T), and 2-8 of weeks PP. PK parameters were characterized using noncompartmental analysis, and comparisons were made using geometric mean ratios (GMRs) with 90% confidence intervals (CI). Twenty-seven participants were included: 11 African, 9 Asian, 3 Hispanic, and 4 mixed descent. PK data were available for 17, 21, and 14 participants in 2T, 3T, and PP, respectively. Rifampin and pyrazinamide AUC 0-24 and C max in pregnancy were comparable to PP with the GMR between 0.80 and 1.25. Compared to PP, isoniazid AUC 0-24 was 25% lower and C max was 23% lower in 3T. Ethambutol AUC 0-24 was 39% lower in 3T but limited by a low PP sample size. In summary, isoniazid and ethambutol concentrations were lower during pregnancy compared to PP concentrations, while rifampin and pyrazinamide concentrations were similar. However, the median AUC 0-24 for rifampin, isoniazid, and pyrazinamide met the therapeutic targets. The clinical impact of lower isoniazid and ethambutol exposure during pregnancy needs to be determined., Competing Interests: The authors declare no conflict of interest.

Background: Despite its federally restricted status, cannabis is widely used medicinally and recreationally. The pharmacokinetics (PK) and central nervous system (CNS) effects of tetrahydrocannabinol (THC), the major psychoactive cannabinoid, are not well understood. The objective of this study was to develop a population PK model of inhaled THC, including sources of variability, and to conduct an exploratory analysis of potential exposure-response relationships., Methods: Regular adult cannabis users smoked a single cannabis cigarette containing 5.9% THC (Chemovar A) or 13.4% THC (Chemovar B) ad libitum. THC concentrations in whole blood were measured and used to develop a population PK model to identify potential factors contributing to interindividual variability in THC PK and to describe THC disposition. Relationships between model-predicted exposure and heart rate, change in composite driving score on a driving simulator, and perceived highness were evaluated., Results: From the 102 participants, a total of 770 blood THC concentrations were obtained. A two-compartment structural model adequately fit the data. Chemovar and baseline THC (THC BL ) were found to be significant covariates for bioavailability, with Chemovar A having better THC absorption. The model predicted that heavy users-those with the highest THC BL -would have significantly higher absorption than those with lighter previous use. There was a statistically significant relationship between exposure and heart rate, and exposure and perceived highness., Conclusions: THC PK is highly variable and related to baseline THC concentrations and different chemovars. The developed population PK model showed that heavier users had higher THC bioavailability. To better understand the factors affecting THC PK and dose-response relationships, future studies should incorporate a wide range of doses, multiple routes of administration, and different formulations relevant to typical community use., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objective: High variability in vancomycin exposure in neonates requires advanced individualized dosing regimens. Achieving steady-state trough concentration (C 0 ) and steady-state area-under-curve (AUC 0-24 ) targets is important to optimize treatment. The objective was to evaluate whether machine learning (ML) can be used to predict these treatment targets to calculate optimal individual dosing regimens under intermittent administration conditions., Methods: C 0 were retrieved from a large neonatal vancomycin dataset. Individual estimates of AUC 0-24 were obtained from Bayesian post hoc estimation. Various ML algorithms were used for model building to C 0 and AUC 0-24 . An external dataset was used for predictive performance evaluation., Results: Before starting treatment, C 0 can be predicted a priori using the Catboost-based C 0 -ML model combined with dosing regimen and nine covariates. External validation results showed a 42.5% improvement in prediction accuracy by using the ML model compared with the population pharmacokinetic model. The virtual trial showed that using the ML optimized dose; 80.3% of the virtual neonates achieved the pharmacodynamic target (C 0 in the range of 10-20 mg/L), much higher than the international standard dose (37.7-61.5%). Once therapeutic drug monitoring (TDM) measurements (C 0 ) in patients have been obtained, AUC 0-24 can be further predicted using the Catboost-based AUC-ML model combined with C 0 and nine covariates. External validation results showed that the AUC-ML model can achieve an prediction accuracy of 80.3%., Conclusion: C 0 -based and AUC 0-24 -based ML models were developed accurately and precisely. These can be used for individual dose recommendations of vancomycin in neonates before treatment and dose revision after the first TDM result is obtained, respectively., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Ethosuximide was identified as the optimal option for new-onset childhood absence epilepsy (CAE) in a randomized, two-phase dose escalation comparative effectiveness trial of ethosuximide, lamotrigine, and valproic acid. However, 47% of ethosuximide initial monotherapy participants experienced short-term treatment failure. This study aimed to characterize the initial monotherapy ethosuximide exposure-response relationship and to propose model-informed precision dosing guidance. Dose titration occurred over a 16-20-week period until patients experienced seizure freedom or intolerable side effects. Subjects with initial monotherapy failure were randomized to one of the other two medications and dose escalation was repeated. A population pharmacokinetic model was created using plasma concentration data (n = 1,320), collected at 4-week intervals from 211 unique participants during both the initial and second monotherapy phases. A logistic regression analysis was performed on the initial monotherapy cohort (n = 103) with complete exposure-response data. Eighty-four participants achieved seizure freedom with a wide range of ethosuximide area under the curves (AUC) ranging from 420 to 2,420 μg·h/mL. AUC exposure estimates for achieving a 50% and 75% probability of seizure freedom were 1,027 and 1,489 μg·h/mL, respectively, whereas the corresponding cumulative frequency of intolerable adverse events was 11% and 16%. Monte Carlo Simulation indicated a daily dose of 40 and 55 mg/kg to achieve 50% and 75% probability of seizure freedom in the overall population, respectively. We identified the need for adjusted mg/kg dosing in different body weight cohorts. This ethosuximide proposed model-informed precision dosing guidance to achieve seizure freedom carries promise to optimize initial monotherapy success for patients with CAE., (© 2023 The Authors. Clinical Pharmacology & Therapeutics © 2023 American Society for Clinical Pharmacology and Therapeutics.)

Background: Fexofenadine is a recommended in vivo probe drug for phenotyping P-glycoprotein (P-gp) and organic anion transporting polypeptide (OATP) 1B1/3 transporter activities. This study evaluated a limited sampling strategy using a population pharmacokinetic approach to estimate plasma fexofenadine exposure as an index of P-gp and OATP activities., Methods: In a previous study, a single oral dose of fexofenadine (120 mg) was administered alone or in combination with grapefruit juice, Panax ginseng , or Echinacea purpurea to healthy adult participants. Serial plasma samples were collected up to 72 hours after administration and fexofenadine concentrations were measured. A population pharmacokinetic model was developed using nonlinear mixed-effects modeling. Limited sampling models (LSMs) using single and 2-timepoint fexofenadine concentrations were compared with full profiles from intense sampling using empirical Bayesian post hoc estimations of systemic exposure derived from the population pharmacokinetic model. Predefined criteria for LSM selection and validation included a coefficient of determination (R 2 ) ≥ 0.90, relative percent mean prediction error ≥ -5 to ≤5%, relative percent mean absolute error ≤ 10%, and relative percent root mean square error ≤ 15%., Results: Fexofenadine concentrations (n = 1520) were well described using a 2-compartment model. Grapefruit juice decreased the relative oral bioavailability of fexofenadine by 25%, whereas P. ginseng and E. purpurea had no effect. All the evaluated single timepoint fexofenadine LSMs showed unacceptable percent mean prediction error, percent mean absolute error, and/or percent root mean square error. Although adding a second time point improved precision, the predefined criteria were not met., Conclusions: Identifying novel fexofenadine LSMs to estimate P-gp and OATP1B1/3 activities in healthy adults for future transporter-mediated drug-drug interaction studies remains elusive., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: People with human immunodeficiency virus (PWH) are at increased risk for comorbidities, and plasma interleukin 6 (IL-6) levels are among the most robust predictors of these outcomes. Tocilizumab (TCZ) blocks the receptor for IL-6, inhibiting functions of this cytokine., Methods: This was a 40-week, placebo-controlled, crossover trial (NCT02049437) where PWH on stable antiretroviral therapy (ART) were randomized to receive 3 monthly doses of TCZ or matching placebo intravenously. Following a 10-week treatment period and a 12-week washout, participants were switched to the opposite treatment. The primary endpoints were safety and posttreatment levels of C-reactive protein (CRP) and CD4+ T-cell cycling. Secondary endpoints included changes in inflammatory indices and lipid levels., Results: There were 9 treatment-related toxicities of grade 2 or greater during TCZ administration (mostly neutropenia) and 2 during placebo administration. Thirty-one of 34 participants completed the study and were included in a modified intent-to-treat analysis. TCZ reduced levels of CRP (median decrease, 1819.9 ng/mL, P < .0001; effect size, 0.87) and reduced inflammatory markers in PWH, including D-dimer, soluble CD14, and tumor necrosis factor receptors. T-cell cycling tended to decrease in all maturation subsets after TCZ administration, but was only significant among naive CD4 T cells. Lipid levels, including lipid classes that have been related to cardiovascular disease risk, increased during TCZ treatment., Conclusions: TCZ is safe and decreases inflammation in PWH; IL-6 is a key driver of the inflammatory environment that predicts morbidity and mortality in ART-treated PWH. The clinical significance of lipid elevations during TCZ treatment requires further study. Clinical Trials Registration. NCT02049437., Competing Interests: Potential conflicts of interest. N. T. F. reports grants or contracts from the NIH and Gilead, and has served as a consultant for Gilead. C. T. L. has received research grants from Gilead Sciences and Medtronic Foundation and has served on an advisory board for Esperion Therapeutics. A. L. has served as a consultant to Abbott. G. A. M. reports grants or contracts from Pfizer, Astellas, Roche, Genentech, Redhill, Cognivue, Vanda, and Tetraphase; served as scientific advisor and consultant for Gilead, Merck, Janssen, Theratechnologies, and GSK/ViiV; and received payment for expert testimony from Gilead. M. M. L. has received competitive grant funding from Gilead and has served as consultant for Merck. C. F. reports serving as a paid consultant for Gilead, Janssen, Merck, American Gene Technologies, Thera Technologies, Shinogi, and ViiV Healthcare; payment or honoraria for speaking engagements from International AIDS Society–USA and Virology Education; payment for expert testimony from Gilead Sciences; 3 issued or pending patents related to long-acting delivery of antiretroviral drugs; and participation on the scientific advisory board for Navigen Corporation and data and safety monitoring board (DSMB) or advisory board for Watermark, LLC. L. H. C. reports consulting fees from Sanofi Genzyme, Genetech, GSK, BMS, Galvani, and UCB; payment or honoraria for nonbranded speaking engagements from Sanofi and AstraZeneca. E. V. C. reports participation on a Melinta Pharmaceuticals data and safety monitoring board for a pediatric antibacterial study. D. D. A. reports a grant from the Department of Defense (grant number 12935153). C. L. S. reports a VA Merit Award and VA Career Development Award. B. R. has received payment or honoraria from Gilead Sciences, ViiV Healthcare, and Theratechnologies (paid to author). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Broadly neutralizing antibodies (bNAbs) may provide an alternative to standard antiretroviral treatment (ART) for controlling HIV-1 replication and may have immunotherapeutic effects against HIV-1 reservoirs. We conducted a prospective clinical trial with two HIV-1 bNAbs (VRC01LS and 10-1074) in children ( n = 25) who had previously initiated small-molecule ART treatment before 7 days of age and who continued treatment for at least 96 weeks. Both bNAbs were dosed intravenously every 4 weeks, overlapping with ART for at least 8 weeks and then continued for up to 24 weeks or until detectable viremia of HIV-1 RNA rose above 400 copies per milliliter in the absence of ART. Eleven (44%) children maintained HIV-1 RNA below 400 copies per milliliter through 24 weeks of bNAb-only treatment; 14 (56%) had detectable viremia above 400 copies per milliliter at a median of 4 weeks. Archived HIV-1 provirus susceptible to 10-1074, lower birth HIV-1 DNA reservoir in peripheral blood mononuclear cells, sustained viral suppression throughout early life, and combined negative qualitative HIV-1 DNA polymerase chain reaction and negative HIV-1 serology at entry were associated with maintaining suppression on bNAbs alone. This proof-of-concept study suggests that bNAbs may represent a promising treatment modality for infants and children living with HIV-1. Future studies using newer bNAb combinations with greater breadth and potency are warranted.

Study Objective: Treatment of HIV and tuberculosis co-infection leads to significant mortality in pediatric patients, and treatment can be challenging due to the clinically significant drug-drug interaction (DDI) between lopinavir/ritonavir (LPV/RTV) and rifampin. Doubling LPV/RTV results in insufficient lopinavir trough concentrations in pediatric patients. The objective of this study was to leverage physiologically based pharmacokinetic (PBPK) modeling to optimize the adjusted doses of LPV/RTV in children receiving the WHO-revised doses of rifampin (15 mg/kg daily)., Design: Adult and pediatric PBPK models for LPV/RTV with rifampin were developed, including CYP3A and P-glycoprotein inhibition and induction., Setting (or Data Source): Data for LPV/RTV model development and evaluation were available from the pediatric AIDS Clinical Trials Group., Patients: Dosing simulations were next performed to optimize dosing in children (2 months to 8 years of age)., Intervention: Exposure following super-boosted LPV/RTV with 10 and 15 mg/kg PO daily rifampin was simulated., Measurements and Main Results: Simulated parameters were within twofold observations for LPV, RTV, and rifampin in adults and children ≥2 weeks old. The model predicted that, in healthy adults receiving 400/100 mg oral LPV/RTV twice daily (BID), co-treatment with 600 mg oral rifampin daily decreased the steady-state area under the concentration vs. time curve of LPV by 79%, in line with the observed change of 75%. Simulated and observed concentration profiles were comparable for LPV/RTV (230/57.5 mg/m 2 ) PO BID without rifampin and 230/230 mg/m 2 LPV/RTV PO BID with 10 mg/kg PO daily rifampin in pediatric patients. Sixteen mg/kg of super-boosted LPV (LPV/RTV 1:1) PO BID with 15 mg/kg PO daily rifampin achieved simulated LPV troughs >1 mg/L in ≥93% of virtual children weighing 3.0-24.9 kg, which was comparable with 10 mg/kg PO daily rifampin., Conclusions: Super-boosted LPV/RTV with 15 mg/kg rifampin achieves therapeutic LPV troughs in HIV/TB-infected simulated children., (© 2022 The Authors. Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy published by Wiley Periodicals LLC on behalf of Pharmacotherapy Publications, Inc.)

Background: Human monoclonal antibodies might offer an important new approach to reduce malaria morbidity and mortality. In the first two parts of a three-part clinical trial, the antimalarial monoclonal antibody CIS43LS conferred high protection against parasitaemia at doses of 20 mg/kg or 40 mg/kg administered intravenously followed by controlled human malaria infection. The ability of CIS43LS to confer protection at lower doses or by the subcutaneous route is unknown. We aimed to provide data on the safety and optimisation of dose and route for the human antimalaria monoclonal antibody CIS43LS., Methods: VRC 612 Part C was the third part of a three-part, first-in-human, phase 1, adaptive trial, conducted at the University of Maryland, Baltimore Center for Vaccine Development and Global Health, Baltimore, MD, USA. We enrolled adults aged 18-50 years with no previous malaria vaccinations or infections, in a sequential, dose-escalating manner. Eligible participants received the monoclonal antibody CIS43LS in a single, open-label dose of 1 mg/kg, 5 mg/kg, or 10 mg/kg intravenously, or 5 mg/kg or 10 mg/kg subcutaneously. Participants underwent controlled human malaria infection by the bites of five mosquitoes infected with Plasmodium falciparum 3D7 strain approximately 8 weeks after their monoclonal antibody inoculation. Six additional control participants who did not receive CIS43LS underwent controlled human malaria infection simultaneously. Participants were followed-up daily on days 7-18 and day 21, with qualitative PCR used for P falciparum detection. Participants who tested positive for P falciparum were treated with atovaquone-proguanil and those who remained negative were treated at day 21. Participants were followed-up until 24 weeks after dosing. The primary outcome was safety and tolerability of CIS43LS at each dose level, assessed in the as-treated population. Secondary outcomes included protective efficacy of CIS43LS after controlled human malaria infection. This trial is now complete and is registered with ClinicalTrials.gov, NCT04206332., Findings: Between Sept 1, 2021, and Oct 29, 2021, 47 people were assessed for eligibility and 31 were enrolled (one subsequently withdrew and was replaced) and assigned to receive doses of 1 mg/kg (n=7), 5 mg/kg (n=4), and 10 mg/kg (n=3) intravenously and 5 mg/kg (n=4) and 10 mg/kg (n=4) subcutaneously, or to the control group (n=8). CIS43LS administration was safe and well tolerated; no serious adverse events occurred. CIS43LS protected 18 (82%) of 22 participants who received a dose. No participants developed parasitaemia following dosing at 5 mg/kg intravenously or subcutaneously, or at 10 mg/kg intravenously or subcutaneously. All six control participants and four of seven participants dosed at 1 mg/kg intravenously developed parasitaemia after controlled human malaria infection., Interpretation: CIS43LS was safe and well tolerated, and conferred protection against P falciparum at low doses and by the subcutaneous route, providing evidence that this approach might be useful to prevent malaria across several clinical use cases., Funding: National Institute of Allergy and Infectious Diseases, National Institutes of Health., Competing Interests: Declaration of interests AHI and RAS are listed as inventors on a pending patent application describing CIS43 and related antibodies. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Early antiretroviral treatment (ART) improves outcomes in children, but few studies have comprehensively evaluated the impact of ART started from the first week of life., Methods: Children diagnosed with HIV within 96 hours of life were enrolled into the Early Infant Treatment Study in Botswana and followed on ART for 96 weeks. Nevirapine, zidovudine, and lamivudine were initiated; nevirapine was switched to lopinavir/ritonavir between weeks 2-5 in accordance with gestational age. Clinical and laboratory evaluations occurred at weeks 1, 2, 4, 8, 12, 24, 36, 48, 60, 72, 84, and 96., Findings: Forty children initiated ART at a median of 2 (IQR 2, 3) days of life; 38 (95%) completed follow-up through 96 weeks, and 2 (5%) died between 12 and 24 weeks. ART was well tolerated; 9 children (24%) experienced a grade 3 or 4 hematologic event, and 2 (5%) required treatment modification for anemia. The median 96-week CD4 count was 1625 (IQR 1179, 2493) cells/mm 3 with only 5/38 (13%) having absolute counts <1000 cells/mm 3 . Although 23 (61%) had at least one visit with HIV-1 RNA ≥40 copies/mL at or after 24 weeks, 28 (74%) had HIV-1 RNA <40 copies/mL at the 96-week visit. Median cell-associated HIV-1 DNA at 84/96-week PBMCs was 1.9 (IQR 1.0, 2.6) log 10 copies/10 6 cells. Pre-ART reservoir size at birth was predictive of the viral reservoir at 84/96 weeks., Interpretation: Initiation of ART in the first week of life led to favorable clinical outcomes, preserved CD4 cell counts, and low viral reservoir through 96 weeks of life., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Young women in sub-Saharan Africa continue to bear a high burden of HIV infection. Combination anti-HIV monoclonal antibodies are a potential HIV prevention technology that could overcome adherence challenges of daily oral pre-exposure prophylaxis. In this phase 1 clinical trial we aimed to determine the safety and pharmacokinetic profile of the broadly neutralising monoclonal antibody CAP256V2LS., Methods: CAPRISA 012B, a first-in-human dose-escalation phase 1 trial evaluated the safety, pharmacokinetics, and neutralisation activity of CAP256V2LS alone and in combination with VRC07-523LS in young HIV-negative women in Durban, South Africa. Groups 1 and 2 were open label with CAP256V2LS administered at 5 mg/kg and 10 mg/kg intravenously and 5 mg/kg, 10 mg/kg, and 20 mg/kg subcutaneously. In group 3, participants were randomly allocated to receive a combination of CAP256V2LS and VRC07-523LS at 10 mg/kg and 20 mg/kg subcutaneously comixed with ENHANZE, a recombinant human hyaluronidase. Once safety was established in the first three participants, dose escalation took place sequentially following review of safety data. Primary endpoints were the proportion of participants with mild, moderate, and severe reactogenicity or adverse events, graded as per the Division of AIDS toxicity grading. The trial is registered on the Pan African Clinical Trial Registry, PACTR202003767867253, and is recruiting., Findings: From July 13, 2020, to Jan 13, 2021, 42 HIV-negative women, aged 18-45 years, were enrolled. All 42 participants, eight with intravenous and 34 with subcutaneous administration, completed the trial. There were no serious adverse events or dose-limiting toxicities. Most commonly reported symptoms following intravenous administration were headaches in seven (88%) and nausea in four (50%) participants. Commonly reported symptoms following subcutaneous administration were headache in 31 (91%), chills in 25 (74%), and malaise or fatigue in 19 (56%) participants. Adverse events included transient lymphocytopenia in eight (19%), proteinuria in nine (21%), elevated aspartate aminotransferase in ten (24%), and alanine aminotransferase in five (12%) participants., Interpretation: CAP256V2LS administered alone and in combination with VRC07-523LS was safe with favourable pharmacokinetics and neutralisation activity, supporting further assessment in larger clinical studies., Funding: European and Developing Countries Clinical Trials Partnership, South African Medical Research Council, and South African Department of Science and Innovation., Competing Interests: Declaration of interests NDR, JRM, PLM, LM, and SSAK are listed as co-inventors on patent US 10 519 222, issued 2019, on broadly neutralising monoclonal antibodies against the HIV-1 V1V2 env region. QAK is a co-chair on the UN Sustainable Development Goals 10 Member Technology Facilitation Mechanism, on the Vice-Chair Advisory Group of the WHO–Human Reproduction Programme Alliance Advisory Board, and the President of the World Academy of Science. SAK is a member of the WHO Science Council and the Vice-President of the International Science Council. SAK has received honoraria for participation in the Sanofi medical advisory committee on COVID-19 vaccines and was sponsored by Sanofi for the 2022 Options for the Control of Influenza conference in Belfast, UK. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Treatment and prophylaxis options for neonatal HIV are limited. This study aimed to develop a population pharmacokinetic model to characterize the disposition of maraviroc in neonates to inform dosing regimens and expand available options., Methods: Using maraviroc concentrations from neonates who received either a single dose or multiple doses of 8 mg/kg of maraviroc in the first 6 weeks of life, a population pharmacokinetic model was developed to determine the effects of age, sex, maternal efavirenz exposure and concomitant ARV therapy on maraviroc disposition. The final model was used in Monte Carlo simulations to generate expected exposures with recommended dosing regimens., Results: A total of 396 maraviroc concentrations, collected in the first 4 days of life, at 1 week, at 4 weeks and at 6 weeks, from 44 neonates were included in the analysis. After allometrically scaling for weight, age less than 4 days was associated with a 44% decreased apparent clearance compared with participants 7 days to 6 weeks of life. There were no differences identified in apparent clearance or volume of distribution from ages 7 days to 6 weeks, sex, maternal efavirenz exposure or concomitant nevirapine therapy. Monte Carlo simulations with FDA-approved weight band dosing resulted in the majority of simulated patients (84.3%) achieving an average concentration of ≥75 ng/mL., Conclusions: While maraviroc apparent clearance is decreased in the first few days of life, the current FDA-approved maraviroc weight band dosing provides maraviroc exposures for neonates in the first 6 weeks of life, which were consistent with adult maraviroc exposure range. Maraviroc provides another antiretroviral treatment option for very young infants., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Broadly neutralizing monoclonal antibodies (bNAbs) suppress HIV-1 RNA and may deplete residual viral reservoirs. We evaluated the safety and pharmacokinetics (PK) of dual intravenous VRC01LS and 10-1074 in very early-treated children with HIV-1 on suppressive antiretroviral treatment (ART)., Setting: Botswana., Methods: Children with HIV-1 (median age 3.1 years) on ART from <7 days old were enrolled. In phase A, 6 children received 10-1074 (30 mg/kg at day 0, 28, and 56) and 6 children received VRC01LS (30 mg/kg at day 0, 10 mg/kg at days 28 and 56) by intravenous infusion. In phase B, 6 children received the 2 bNAbs combined (with higher VRC01LS maintenance dose, 15 mg/kg) every 4 weeks for 32 weeks with PK evaluations over 8 weeks. Population PK models were developed to predict steady-state concentrations., Results: BNAb infusions were well tolerated. There were no infusion reactions nor any bNAb-related grade 3 or 4 events. The median (range) first dose Cmax and trough (day 28) combined from both phases were 1405 (876-1999) μg/mL and 133 (84-319) μg/mL for 10-1074 and 776 (559-846) μg/mL and 230 (158-294) μg/mL for VRC01LS. No large differences in bNAb clearances were observed when given in combination. The estimated VRC01LS half-life was shorter than in adults. Predicted steady-state troughs [median (90% prediction interval)] were 261 (95-565) and 266 (191-366) μg/mL for 10-1074 and VRC01LS, respectively, when given in combination., Conclusions: 10-1074 and VRC01LS were safe and well-tolerated among children receiving ART. Troughs exceeded minimal targets with every 4-week administration of 10-1074 at 30 mg/kg and VRC01LS at 15 mg/kg., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Isoniazid (INH) metabolism depends on the N-acetyl transferase 2 (NAT2) enzyme, whose maturation process remains unknown in low birth weight (LBW) and preterm infants. We aimed to assess INH exposure and safety in infants receiving oral tuberculosis prevention., Methods: This population pharmacokinetics (PK) analysis used INH and N-acetyl-isoniazid (ACL) concentrations in infants (BW ≤ 4 kg), including preterm, with follow-up for 6 months. PK parameters were described using nonlinear mixed effects modeling. Simulations were performed to assess INH exposure and optimal dosing regimens, using 2 targets: Cmax at 3-6 mg/L and area under the curve (AUC) ≥ 10.52 mg h/L., Results: We included 57 infants (79% preterm, 84% LBW) in the PK analysis, with a median (range) gestational age of 34 (28.7-39.4) weeks. At the time of sampling, postnatal age was 2.3 (0.2-7.3) months and weight (WT) was 3.7 (0.9-9.3) kg. NAT2 genotype was available in 43 (75.4%) patients (10 slow, 26 intermediate, and 7 fast metabolizers). Ninety percent of NAT2 maturation was attained by 4.4 post-natal months. WT, postmenstrual age, and NAT2 genotype significantly influenced INH exposure, with a 5-fold difference in AUC between slow and fast metabolizers for the same dose. INH appeared safe across the broad range of exposure for 61 infants included in the safety analysis., Conclusions: In LBW/preterm infants, INH dosing needs frequent adjustment to account for growth and maturation. Pharmacogenetics-based dosing regimens is the most powerful approach to deliver safe and equalized exposures for all infants, because NAT2 genotype highly impacts INH pharmacokinetic variability., Competing Interests: Potential conflicts of interest. M. C. received honorariums from ViiV Healthcare for a lecture at ViiV interest meeting. M. M. received grant supports from ViiV Healthcare, Merck & Co, and Gilead Sciences. A. V. is a member of the DSMB for Janssen for a pediatric trial funded by Janssen and received some grants for work done for MSD and Gilead Sciences. E. V. C. participated in the DSMB for Celltrion. J. M. reports being a US ­government employee during the conduct of the study. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Safe and effective paediatric formulations of the most promising antiretroviral drugs are crucial to advance the treatment and prevention of HIV in neonates, infants, children, and adolescents. The WHO Paediatric Drug Optimization for HIV (PADO-HIV) group brings together stakeholders and experts every 2-3 years to identify priority products and define research gaps in the development of new HIV drugs and formulations for children in low-income and middle-income countries. PADO-HIV 5 met from Sept 27 to Oct 15, 2021. The group evaluated HIV agents from known and novel drug classes, oral and parenteral long-acting formulations, and developments in broadly neutralising antibodies, and included focused sessions on neonates and new delivery technologies. A list of medium-term and long-term priorities was generated, and research questions were defined. This forward-looking analysis is intended to provide guidance to funders, drug developers, and researchers, and to accelerate access for children to the best HIV drugs and formulations., Competing Interests: Declaration of interests AC received research grants from Merck, Gilead, and ViiV Healthcare, and a consultancy fee from Merck, all paid to AC's institution. PR received research grants from ViiV and has been on an advisory board for Merck. MV received educational grants from ViiV, Janssen, and MSD. All other authors declare no competing interests., (Copyright © 2022 World Health Organization. Published by Elsevier Ltd. All rights reserved. Published by Elsevier Ltd.. All rights reserved.)

Background: Effective, long-acting prevention approaches are needed to reduce human immunodeficiency virus (HIV) incidence. We evaluated the safety and pharmacokinetics of VRC07-523LS and PGT121 administered subcutaneously alone and in combination as passive immunization for young women in South Africa., Methods: CAPRISA 012A was a randomized, double-blinded, placebo-controlled, dose-escalation phase 1 trial. We enrolled 45 HIV-negative women into 9 groups and assessed safety, tolerability, pharmacokinetics, neutralization activity, and antidrug antibody levels. Pharmacokinetic modeling was conducted to predict steady-state concentrations for 12- and 24-weekly dosing intervals., Results: VRC07-523LS and PGT121, administered subcutaneously, were safe and well tolerated. Most common reactogenicity events were injection site tenderness and headaches. Nine product-related adverse events were mild and transient. Median VRC07-523LS concentrations after 20 mg/kg doses were 9.65 μg/mL and 3.86 μg/mL at 16 and 24 weeks. The median week 8 concentration after the 10 mg/kg PGT121 dose was 8.26 μg/mL. Modeling of PGT121 at 20 mg/kg showed median concentrations of 1.37 μg/mL and 0.22 μg/mL at 16 and 24 weeks. Half-lives of VRC07-523LS and PGT121 were 29 and 20 days. Both antibodies retained neutralizing activity postadministration and no antidrug antibodies were detected., Conclusions: Subcutaneous administration of VRC07-523LS in combination with optimized versions of PGT121 or other antibodies should be further assessed for HIV prevention., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America.)