Browsing by Author "Chakhtoura, Nahida"

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Association of Maternal Viral Load and CD4 Count With Perinatal HIV-1 Transmission Risk During Breastfeeding in the PROMISE Postpartum Component.
(2021-Oct-01) Flynn, Patricia M.; Taha, Taha E.; Cababasay, Mae; Butler, Kevin; Fowler, Mary G.; Mofenson, Lynne M.; Owor, Maxensia; Fiscus, Susan; Stranix-Chibanda, Lynda; Coutsoudis, Anna; Gnanashanmugam, Devasena; Chakhtoura, Nahida; McCarthy, Katie; Frenkel, Lisa; Beck, Ingrid; Mukuzunga, Cornelius; Makanani, Bonus; Moodley, Dhayendre; Nematadzira, Teacler; Kusakara, Bangani ; Patil, Sandesh; Vhembo, Tichaona; Bobat, Raziya; Mmbaga, Blandina T.; Masenya, Maysseb ; Nyati, Mandisa ; Theron, Gerhard; Mulenga, Helen; Shapiro, David E.
BACKGROUND: Breastfeeding mothers with HIV infection not qualifying for antiretroviral therapy (ART) based on country-specific guidelines at the time of the Promoting Maternal-Infant Survival Everywhere trial and their uninfected neonates were randomized to maternal ART (mART) or infant nevirapine prophylaxis (iNVP) postpartum. HIV transmission proportions were similar (<1%) in the 2 arms. We assessed whether maternal viral load (MVL) and CD4 cell counts were associated with breastfeeding HIV transmission. METHODS: MVL was collected at entry (7-14 days postpartum) and at weeks 6, 14, 26, and 50 postpartum. CD4 cell counts were collected at entry and weeks 14, 26, 38, and 50 postpartum. Infant HIV-1 nucleic acid test was performed at weeks 1 and 6, every 4 weeks until week 26, and then every 12 weeks. The associations of baseline and time-varying MVL and CD4 cell counts with transmission risk were assessed using time-to-event analyses by randomized treatment arm. RESULTS: Two thousand four hundred thirty-one mother-infant pairs were enrolled in the study. Baseline MVL (P = 0.11) and CD4 cell counts (P = 0.51) were not significantly associated with infant HIV-1 infection. Time-varying MVL was significantly associated with infant HIV-1 infection {hazard ratio [95% confidence interval (CI)]: 13.96 (3.12 to 62.45)} in the mART arm but not in the iNVP arm [hazard ratio (95% CI): 1.04 (0.20 to 5.39)]. Time-varying CD4 cell counts were also significantly associated with infant HIV-1 infection [hazard ratio (95% CI): 0.18 (0.03 to 0.93)] in the mART arm but not in the iNVP arm [hazard ratio (95% CI): 0.38 (0.08 to 1.77)]. CONCLUSIONS: In women receiving mART, increased MVL and decreased CD4 cell counts during breastfeeding were associated with increased risk of infant HIV-1 infection.
Establishing Dosing Recommendations for Efavirenz in HIV/TB-Coinfected Children Younger Than 3 Years.
(2019-Aug-01) Dangarembizi, Mutsa B.; Samson, Pearl; Capparelli, Edmund V.; Bolton-Moore, Carolyn; Jean-Philippe, Patrick; Spector, Stephen A.; Chakhtoura, Nahida; Benns, Alex; Zimmer, Bonnie; Purdue, Lynette; Jackson, Chivon; Wallis, Carole; Libous, Jennifer L.; Chadwick, Ellen G.
BACKGROUND: CYP2B6 516 genotype-directed dosing improves efavirenz (EFV) exposures in HIV-infected children younger than 36 months, but such data are lacking in those with tuberculosis (TB) coinfection. METHODS: Phase I, 24-week safety and pharmacokinetic (PK) study of EFV in HIV-infected children aged 3 to <36 months, with or without TB. CYP2B6 516 genotype classified children into extensive metabolizers (516 TT/GT) and poor metabolizers [(PMs), 516 TT]. EFV doses were 25%-33% higher in children with HIV/TB coinfection targeting EFV area under the curve (AUC) 35-180 μg × h/mL, with individual dose adjustment as necessary. Safety and virologic evaluations were performed every 4-8 weeks. RESULTS: Fourteen children from 2 African countries and India with HIV/TB enrolled, with 11 aged 3 to <24 months and 3 aged 24-36 months, 12 extensive metabolizers and 2 PMs. Median (Q1, Q3) EFV AUC was 92.87 (40.95, 160.81) μg × h/mL in 8/9 evaluable children aged 3 to <24 months and 319.05 (172.56, 360.48) μg × h/mL in children aged 24-36 months. AUC targets were met in 6/8 and 2/5 of the younger and older age groups, respectively. EFV clearance was reduced in PM's and older children. Pharmacokinetic modeling predicted adequate EFV concentrations if children younger than 24 months received TB-uninfected dosing. All 9 completing 24 weeks achieved viral suppression. Five/14 discontinued treatment early: 1 neutropenia, 3 nonadherence, and 1 with excessive EFV AUC. CONCLUSIONS: Genotype-directed dosing safely achieved therapeutic EFV concentrations and virologic suppression in HIV/TB-coinfected children younger than 24 months, but further study is needed to confirm appropriate dosing in those aged 24-36 months. This approach is most important for young children and currently a critical unmet need in TB-endemic countries.
Impact of CYP2B6 genotype, tuberculosis therapy, and formulation on efavirenz pharmacokinetics in infants and children under 40 months of age.
(2022-Mar-15) Nikanjam, Mina; Tran, Lana; Chadwick, Ellen G.; Bwakura-Dangarembizi, Mutsa; Bolton-Moore, Carolyn; Samson, Pearl; Spector, Stephen A.; Chakhtoura, Nahida; Jean-Philippe, Patrick; Frenkel, Lisa; Zimmer, Bonnie; Benns, Alex; Libous, Jennifer; Capparelli, Edmund V.
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.
Prevention of HIV-1 Transmission Through Breastfeeding: Efficacy and Safety of Maternal Antiretroviral Therapy Versus Infant Nevirapine Prophylaxis for Duration of Breastfeeding in HIV-1-Infected Women With High CD4 Cell Count (IMPAACT PROMISE): A Randomized, Open-Label, Clinical Trial.
(2018-Apr-01) Flynn, Patricia M.; Taha, Taha E.; Cababasay, Mae; Fowler, Mary G.; Mofenson, Lynne M.; Owor, Maxensia; Fiscus, Susan; Stranix-Chibanda, Lynda; Coutsoudis, Anna; Gnanashanmugam, Devasena ; Chakhtoura, Nahida; McCarthy, Katie; Mukuzunga, Cornelius; Makanani, Bonus; Moodley, Dhayendre; Nematadzira, Teacler; Kusakara, Bangini ; Patil, Sandesh; Vhembo, Tichaona; Bobat, Raziya; Mmbaga, Blandina T.; Masenya, Maysseb ; Nyati, Mandisa; Theron, Gerhard; Mulenga, Helen; Butler, Kevin; Shapiro, David E.
BACKGROUND: No randomized trial has directly compared the efficacy of prolonged infant antiretroviral prophylaxis versus maternal antiretroviral therapy (mART) for prevention of mother-to-child transmission throughout the breastfeeding period. SETTING: Fourteen sites in Sub-Saharan Africa and India. METHODS: A randomized, open-label strategy trial was conducted in HIV-1-infected women with CD4 counts ≥350 cells/mm (or ≥country-specific ART threshold if higher) and their breastfeeding HIV-1-uninfected newborns. Randomization at 6-14 days postpartum was to mART or infant nevirapine (iNVP) prophylaxis continued until 18 months after delivery or breastfeeding cessation, infant HIV-1 infection, or toxicity, whichever occurred first. The primary efficacy outcome was confirmed infant HIV-1 infection. Efficacy analyses included all randomized mother-infant pairs except those with infant HIV-1 infection at entry. RESULTS: Between June 2011 and October 2014, 2431 mother-infant pairs were enrolled; 97% of women were World Health Organization Clinical Stage I, median screening CD4 count 686 cells/mm. Median infant gestational age/birth weight was 39 weeks/2.9 kilograms. Seven of 1219 (0.57%) and 7 of 1211 (0.58%) analyzed infants in the mART and iNVP arms, respectively, were HIV-infected (hazard ratio 1.0, 96% repeated confidence interval 0.3-3.1); infant HIV-free survival was high (97.1%, mART and 97.7%, iNVP, at 24 months). There were no significant differences between arms in median time to breastfeeding cessation (16 months) or incidence of severe, life-threatening, or fatal adverse events for mothers or infants (14 and 42 per 100 person-years, respectively). CONCLUSIONS: Both mART and iNVP prophylaxis strategies were safe and associated with very low breastfeeding HIV-1 transmission and high infant HIV-1-free survival at 24 months.