Evaluating the Safety and Pharmacokinetics of Maraviroc in HIV-1-Exposed Infants at Risk of Acquiring HIV-1 Infection

Maraviroc is a C-C Chemokine Receptor 5 (CCR5) receptor antagonist used to treat HIV infection in adults. Adding maraviroc to a standard of care prophylaxis regimen may also reduce the risk of perinatal transmission of HIV. The purpose of this study was to evaluate the safety, tolerability, and pharmacokinetics of maraviroc in HIV-1-exposed infants at risk for mother-to-child HIV transmission. This study also aimed to determine an appropriate dose of maraviroc during the first six weeks of life. The study allowed up to 72 mother-infant pairs in two cohorts to achieve a target of 36 evaluable infants receiving the final recommended dose of maraviroc. Because maraviroc interacts with the antiretroviral drug efavirenz (EFV) in adults, infants in this study were stratified within the cohorts based on their exposure to maternal EFV. Cohort 1 was stratified by in utero exposure to maternal EFV, with infants in both strata receiving a single dose of maraviroc solution within three days of birth and another single dose at Week 1 of life. Stratum 1A included infants without in utero exposure to maternal EFV during the eight weeks immediately before delivery. Stratum 1B included infants with in utero exposure to maternal EFV for a minimum of two weeks immediately before delivery. Cohort 2 was stratified by exposure to maternal EFV after birth, with infants in both strata receiving maraviroc oral solution twice daily starting within three days of birth and continuing for up to 42 days. Based on evaluation of the Cohort 1 data, the initial daily dose of maraviroc oral solution to be administered in Cohort 2 was 8 mg/kg dose given twice daily. Stratum 2A included infants without any exposure to maternal EFV either in utero during the eight weeks immediately before delivery or while breastfeeding. Stratum 2B included breastfeeding infants with exposure to maternal EFV both in utero and after birth while breastfeeding, for a minimum of 2 weeks immediately before delivery and while breastfeeding. Participants attended an entry visit within three days after the infant's birth. Participants attended five to six study visits through Week 16. Visits included medical history reviews, physical examinations, blood collection from the mother and/or infant, HIV testing, and adherence counseling.