Safety and Pharmacokinetics of Raltegravir in HIV-1-Exposed Newborn Infants at Risk of Acquiring HIV-1 Infection

This is a Phase I multi-center, open label, non-comparative study to evaluate the safety and PK of RAL administered to HIV-1-exposed full-term (≥37 weeks of gestation) infants when administered during the first 6 weeks of life in addition to the infants' standard HIV-1 ARV prophylaxis. IMPAACT P1097 (NCT01828073) demonstrated that RAL crossed the placenta from mother to fetus after maternal dosing during pregnancy and RAL was slowly eliminated by the newborn after birth. Therefore, for P1110, within each cohort, infants were stratified into the "RAL-naive" or "RAL-exposed" groups depending on infants' in utero exposure to maternal RAL. The study stratification with respect to in utero RAL exposure allowed for adjustment of the initial RAL dosing (i.e. timing and/or dose size). Study participants were enrolled in two sequential cohorts with the following actual dosing of RAL in addition to their local standard of care ARV agents for prevention of perinatal transmission. PK and safety data from Cohort 1 (two single doses) provided information for the starting dosing for Cohort 2 (daily dosing through 6 weeks of life). Cohort 1: Two single RAL doses: first dose within 48 hours of birth and second dose at 7-10 days of life. * Cohort 1, RAL-naive: 3 or 2 mg/kg within 48 hours of birth and 3 mg/kg at 7-10 days of life. (P1110 V1.0 Clarification Memorandum #3, dated January 15, 2015, adjusted the first dose from 3 mg/kg to 2 mg/kg based on available PK data.) * Cohort 1, RAL-exposed: 1.5 mg/kg within 48 hours of birth and 3 mg/kg at 7-10 days of life. Cohort 2: Daily RAL dosing through 6 weeks of life. * Cohort 2, RAL-naive: Daily dosing through 6 weeks of life with initial RAL dosing within 48 hours of birth: 1.5 mg/kg once daily during Days 1-7 of life, 3.0 mg/kg twice daily during Days 8-28 of life, and 6.0 mg/kg twice daily during Days 29-42 of life. * Cohort 2, RAL-exposed: Daily dosing through 6 weeks of life with initial RAL dosing between 12-60 hours of birth: 1.5 mg/kg once daily during Days 1-7 of life, 3.0 mg/kg twice daily during Days 8-28 of life, and 6.0 mg/kg twice daily during Days 29-42 of life. Target enrollment was approximately 50 infants and their mothers in order to have a minimum of 12 and 20 PK evaluable infants in Cohorts 1 and 2, respectively. Cohort 1 and Cohort 2 RAL-naive infants (and their mothers) were enrolled under protocol Version 1.0. Cohort 2 RAL-exposed infants (and their mothers) were enrolled under protocol Version 2.0. Infants and their mothers were enrolled within 48 and within 60 hours of delivery under protocol Versions 1.0 and 2.0, respectively. Infants were followed through 24 weeks of life and their mothers were followed until discharge from the labor and delivery unit. Infant PK samples were collected as follows: Cohort 1: * Dose #1 (within 48 hours of birth) intensive PK sampling: Within 30 min pre-dose, and 1-2 hours post-dose, 4-8 hours post-dose, 12 (±1) hours post-dose, and 24 (±1) hours post-dose. * One random PK sample at 3-4 days of life. * Dose #2 (7-10 days of life) limited PK sampling: Within 30 min pre-dose, and 1-2 hours post-dose and 24 (±1) hours post-dose. Cohort 2: * Initial dose (within 48 and 12-60 hours of birth for RAL-naive and RAL-exposed infants, respectively) intensive PK sampling: Within 1 hour pre-dose, and 1-2 hours, 6-10 hours, 20-24 hours post-dose. * PK sampling for second dose: 3-6 hours post-dose. * PK sampling at 6-9 days of life: Within 1 hour pre-dose of initiating 3mg/kg twice daily. * Intensive PK sampling at 15-18 days of life: Within 1 hour pre-dose, and 1-2 hours post-dose, 4-6 hours post-dose, and 8-12 hours post-dose. * PK sampling at 28-32 days of life: Within 1 hour pre-dose of initiating 6 mg/kg twice daily. * PK sampling at 33-42 days of life done at Week 5-6 visit: Within 1 hour pre-dose, and 3-6 hours post-dose. Protocol defined infant safety evaluations were done at: Cohort 1: Entry, 3-4 days of life, 7-10 days of life, 2 weeks of life, 6 weeks of life and 24 weeks of life. Cohort 2: Entry, 2-4 days of life, 6-9 days of life, 15-18 days of life, 28-32 days of life, 5-6 weeks of life, 8-10 weeks of life and 24 weeks of life. Infant safety data included death, signs/symptoms, diagnoses and laboratory test results. Laboratory test results included results from evaluations specified in the protocol and evaluations done as part of the infant's clinical care which the sites considered relevant. PK evaluable infants were those determined by the protocol pharmacologist to have PK results which provide analyzable data on the primary PK parameters of interest. Infants who were PK unevaluable were replaced for PK analysis but continued with the study safety follow-up visits. Infants were evaluable for safety analysis if they received at least one dose of RAL. The safety analyses were based on data from all safety evaluable infants, regardless of whether they were evaluable for PK analysis. The study initially opened accrual to Cohort 1 RAL-naive group. The PK and safety data from IMPAACT P1110 Cohort 1 RAL-naive group and from IMPAACT P1097 were used to determine the starting dose for the Cohort 1 RAL-exposed group. Opening accrual to the Cohort 2 RAL-naive group was contingent upon infants enrolled in Cohort 1 RAL-naive and RAL-exposed groups successfully meeting safety criteria and providing adequate PK data to determine a regimen to be tested for daily dosing through 6 weeks of life for the Cohort 2 RAL-naive group. The initial dosing regimen for the Cohort 2 RAL-naive group was determined using population PK modeling and simulations incorporating IMPAACT P1110 Cohort 1 data, along with data from the following IMPAACT studies: P1097, P1066 (NCT00485264) (Cohorts IV and V) and P1026s (NCT00042289). Since the PK results of Cohort 1 RAL-naive and exposed groups were similar except in the first 1-2 days of life and P1097 Cohort 1 results suggested that maternal RAL readily crosses the placenta and results to washout RAL exposure in neonates, Cohort 2 RAL-exposed group was determined to receive the same dose of RAL as Cohort 2 RAL-naive group, except the initial dose for RAL-exposed was delayed to within 12 to 60 hours of life.