Safety and Trough Concentrations of Nevirapine Prophylaxis Given Daily, Twice Weekly, or Weekly in Breast-Feeding Infants From Birth to 6 Months

Despite the success of antiretroviral prophylaxis in reducing mother-to-child HIV-1 transmission, postpartum transmission through breast milk remains a problem. Antiretroviral administration to the infant during the period of breast-feeding could protect against postnatal transmission. An open-label phase 1/2 study was designed to assess the safety and trough concentrations of nevirapine (NVP) given once weekly (OW), twice weekly (TW), or once daily (OD) to HIV-exposed breast-feeding infants for 24 weeks. Following maternal dosing with 200 mg NVP orally at onset of labor, breast-feeding infants were randomized within 48 hours of birth to 1 of 3 regimensarm 1, NVP given OW (4 mg/kg from birth to 14 days, ↑ to 8 mg/kg from 15 days to 24 weeks), arm 2, NVP given TW (4 mg/kg from birth to 14 days, ↑ to 8 mg/kg from 15 days to 24 weeks), and arm 3, NVP given OD (2 mg/kg from birth to 14 days, ↑ to 4 mg/kg from 15 days to 24 weeks). Trough NVP concentrations and clinical and laboratory abnormalities were monitored. Of the 75 infants randomized (26 to OW, 25 to TW, and 24 to OD dosing), 63 completed the 32-week follow-up visit. No severe skin, hepatic, or renal toxicity related to NVP was observed. Neutropenia occurred in 8 infants. Trough NVP levels were lower than the therapeutic target (100 ng/mL) in 48 of 75 (64.0%) samples from infants in the OW arm, 3 of 65 (4.6%) samples in the TW arm, and 0 of 72 samples in the OD arm. Median (range) trough NVP concentrations were 64 ng/mL (range