Prevention of HIV-1 transmission through breastfeeding: Efficacy and safety of maternal antiretroviral therapy versus infant nevirapine prophylaxis for duration of breastfeeding in HIV-1-infected women with high CD4 cell count (IMPAACT PROMISE): a randomized, open label, clinical trial

BACKGROUND: No randomized trial has directly compared the efficacy of prolonged infant antiretroviral prophylaxis versus maternal antiretroviral therapy (mART) for prevention of mother-to-child transmission throughout the breastfeeding period. SETTING: Fourteen sites in sub-Saharan Africa and India. METHODS: A randomized, open label strategy trial was conducted in HIV-1-infected women with CD4 counts ≥350 cells/mm(3) (or ≥country-specific ART threshold if higher) and their breastfeeding HIV-1-uninfected newborns. Randomization at 6-14 days postpartum was to mART or infant nevirapine prophylaxis (iNVP) continued until 18 months post-delivery or breastfeeding cessation, infant HIV-1 infection, or toxicity, whichever occurred first. The primary efficacy outcome was confirmed infant HIV-1 infection. Efficacy analyses included all randomized mother-infant pairs except those with infant HIV-1 infection at entry. RESULTS: Between June 2011-October 2014, 2431 mother-infant pairs were enrolled; 97% of women were WHO Clinical Stage I, median screening CD4 count 686 cells/mm(3). Median infant gestational age/birthweight were 39 weeks/2.9 kilograms. Seven of 1219 (0.57%) and seven of 1211 (0.58%) analyzed infants in the mART and iNVP arms, respectively, were HIV-infected (hazard ratio [HR] 1.0, 96% repeated confidence interval 0.3-3.1); infant HIV-free survival was high (97.1%, mART and 97.7%, iNVP, at 24 months). There were no significant differences between arms in median time to breastfeeding cessation (16 months) or incidence of severe, life-threatening or fatal adverse events for mothers or infants (14 and 42 per 100 person-years, respectively). CONCLUSION: Both mART and iNVP prophylaxis strategies were safe and associated with very low breastfeeding HIV-1 transmission and high infant HIV-1-free survival at 24 months.