Maternal or Infant Antiretroviral Drugs to Reduce HIV-1 Transmission

There is a critical need for effective highly active antiretroviral therapy (HAART) to prevent mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) through breast-feeding in low-resource areas of the world where replacement feeding is not feasible. The most effective HAART regimen to prevent HIV transmission during breast-feeding is unknown. This study compared different HAART regimens to determine whether they differ with respect to virologic suppression during pregnancy and breast-feeding, pregnancy outcomes, and adverse effects in mothers and infants. The participants—560 pregnant HIV-1 infected women with CD4+ cell counts of ≥200-were randomly assigned to receive either a coformulation of abacavir, zidovudine, and lamivudine (the nucleoside reverse-transcriptase inhibitor [NRTI] group) or a coformulation of lopinavir-ritonavir plus zidovudine-lamivudine (the protease inhibitor group). Both the regimens were administered between 26 and 34 weeks' gestation and were continued through planned weaning by 6 months postpartum. The observational group—170 women with CD4+ cell counts <200 cells—received standard-of-care treatment (nevirapine plus zidovudine-lamivudine). Infants were given single-dose nevirapine at birth and zidovudine from birth through 4 weeks. There was no significant difference between any of the 3 regimens in the rate of virologic suppression (decrease in plasma HIV-1 RNA level) to less than 400 copies per mL both at delivery (96% in the NRTI group, 93% in the protease inhibitor group, and 94% in the observational group) and throughout the breast-feeding period (92% in the NRTI group, 93% in the protease inhibitor group, and 95% in the observational group). At 6 months, the rates of mother-to-child transmission were low; only 1.1% (8/709) of live-born infants were infected (95% confidence interval, 0.5-2.2). Of the 8 infants infected at 6 months, 6 were infected in utero (4 in the NRTI group, 1 in the protease inhibitor group, and 1 in the observational group) and 2 infants were infected through late breast-feeding transmission (both in the NRTI group). Adverse events required modification of the HAART regimen in 2% of both intervention groups and 11% in the observational group. These findings show that all HAART regimens are highly effective for virologic suppression at delivery and throughout breast-feeding, with an overall rate of mother-to-child HIV transmission of 1.1% at 6 months.