Browsing by Author "Samson P"

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    Impact of CYP2B6 genotype, tuberculosis therapy, and formulation on efavirenz pharmacokinetics in infants and children under 40 months of age.
    (2022-Mar-15) Nikanjam M; Tran L; Chadwick EG; Bwakura-Dangarembizi M; Bolton Moore C; Samson P; Spector SA; Chakhtoura N; Jean-Philippe P; Frenkel L; Zimmer B; Benns A; Libous J; Capparelli EV
    OBJECTIVE: Dosing efavirenz (EFV) in children less than 3 years of age is challenging due to large variability in drug levels. This study evaluated differences in pharmacokinetics with tuberculosis (TB) therapy, formulation, age, and CYP2B6 genotype. DESIGN: Pharmacokinetic data from three IMPAACT/PACTG studies (P382, P1021, and P1070) for children initiating therapy less than 40 months of age were evaluated. METHODS: Pharmacokinetic data were combined in a population pharmacokinetic model. Exposure from the 2-week pharmacokinetic visit was compared with changes in viral RNA between the Week 0 and Week 4 visits. RESULTS: The model included 103 participants (19 on TB therapy). CYP2B6 516 genotype information was available for 82 participants (TT: 15, GT: 28, GG: 39). Median age at the first pharmacokinetic visit was 17.0 months (range: 2.0-39.0 months). Liquid formulation led to a 42% decrease in bioavailability compared with opened capsules. TB therapy (isoniazid and rifampin) led to a 29% decreased clearance, however Monte Carlo simulations demonstrated the majority of participants on TB therapy receiving standard EFV dosing to be in the target area under the curve range. Clearance was 5.3-fold higher for GG than TT genotype and 3.3-fold higher for GT than TT genotype. Age did not have a significant effect on clearance in the final model. Initial viral RNA decay was lower for patients in the lowest quartile of exposures (area under the curves) than for higher quartiles (P = 0.013). CONCLUSION: EFV dosing should account for CYP2B6 516 genotype and formulation, but does not require adjustment for concurrent TB therapy.
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    Safety and pharmacokinetics of oral and long-acting injectable cabotegravir or long-acting injectable rilpivirine in virologically suppressed adolescents with HIV (IMPAACT 2017/MOCHA): a phase 1/2, multicentre, open-label, non-comparative, dose-finding study.
    (2024-Apr) Gaur AH; Capparelli EV; Calabrese K; Baltrusaitis K; Marzinke MA; McCoig C; Van Solingen-Ristea RM; Mathiba SR; Adeyeye A; Moye JH; Heckman B; Lowenthal ED; Ward S; Milligan R; Samson P; Best BM; Harrington CM; Ford SL; Huang J; Crauwels H; Vandermeulen K; Agwu AL; Smith-Anderson C; Camacho-Gonzalez A; Ounchanum P; Kneebone JL; Townley E; Bolton Moore C
    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 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 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.