Use of NNRTI-based regimens as initial therapy for HIV-infected children is increasing, especially in areas where newborns exposed to HIV-1 receive single-dose nevirapine (NVP) as part of prevention of mother-to-child transmission (PMTCT) regimens and/or daily NVP for prevention of transmission through breastfeeding. First-generation NNRTIs have a low genetic barrier to the development of resistance; in two of the most widely used NNRTIs, NVP and efavirenz (EFV), even a single amino acid mutation in the virus can lead to a reduction in the drug's effectiveness. Even short-term use of these NNRTIs, including only a single dose of NVP, can cause NNRTI resistance. Second-generation NNRTIs are needed as part of ARV regimens for newly diagnosed infants and children who have been exposed to single-dose NVP or who have failed their current antiretroviral (ARV) regimens. In this study, the second-generation NNRTI ETR was tested for safety, tolerability, and appropriate dosing.~Children were assigned to one of three cohorts based on age:~Cohort I: At least 2 but younger than 6 years of age~Cohort II: At least 1 but younger than 2 years of age~Cohort III: At least 2 months but younger than 1 year of age~Children in all three cohorts were treatment experienced, defined as being on a failing combination ARV regimen (containing at least 3 ARVs) for at least 8 weeks or having a treatment interruption of at least 4 weeks with a history of virologic failure while on a combination ARV regimen (containing at least 3 ARVs).~Children received ETR together with an optimized background regimen (OBR) consisting of at least 2 active agents (a boosted protease inhibitor [PI] and at least 1 additional active ARV drug). OBR were based on clinical status, treatment history, resistance data, and availability of appropriate pediatric dosing and formulations. The children received an oral dose of ETR twice daily.~Most children had 11 visits: at screening, entry (Day 0), Day 14 (intensive pharmacokinetic [PK] visit), and at Weeks 4, 8, 12, 16, 24, 32, 40, and 48. Most visits included a physical exam, giving a medical history, discussion of adherence, and blood and urine collection. The screening and intensive PK visits also included an electrocardiogram (ECG). During the intensive PK visit, the child had blood drawn approximately 7 times over 12 hours. After the Week 48 visit, children entered the long-term follow-up phase of the study and have a visit every 12 weeks for up to 5 years. These follow-up visits included giving a medical history and undergoing a physical exam and blood draw.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are widely used as part of combination antiretroviral therapy (ART) for infants and children, but NNRTI resistance is increasing, leading to treatment failure. This study tested the safety, tolerability, and dosing levels of etravirine (ETR), a new NNRTI.