Objective: To compare the effect of perinatal regimens of short-course nevirapine (HIVNET 012) and zidovudine [Thai-Centers for Disease Control and Prevention (CDC) regimen] on breast milk viral shedding and perinatal transmission during the first 6 weeks postpartum in a randomized clinical trial.
Design: Randomized clinical trial.
Methods: Pregnant HIV-1 seropositive women in Nairobi, Kenya who planned to breastfeed were randomized to HIVNET 012 or Thai-CDC regimens. Two to four breast milk samples were collected each week between delivery and 6 weeks postpartum. Breast milk HIV-1 RNA was quantified using the Gen-Probe TMA assay. Infants were tested for HIV-1 DNA at birth and 6 weeks.
Results: From March to October 2003, 76 women were enrolled and 795 breast milk samples were collected from 60 women who were randomized and followed after delivery. Between 3 and 21 days postpartum, nevirapine was associated with significantly greater suppression of breast milk log10 HIV-1 RNA: days 3 to 7 (1.98 versus 2.42, P = 0.1); days 8 to 14 (1.78 versus 2.48, P = 0.005); days 15 to 21 (1.90 versus 2.97, P = 0.003). At 6 weeks, the HIV-1 perinatal transmission rate was significantly lower among those who took nevirapine than zidovudine (6.8% versus 30.3%, P = 0.02).
Conclusions: Compared to a peripartum zidovudine regimen, nevirapine was significantly more likely to decrease HIV-1 RNA in breast milk during the first week and through the third week postpartum following single-dose administration, and corresponded with decreased transmission risk at 6 weeks. Sustained breast milk HIV-1 suppression may contribute to the ability of nevirapine to decrease perinatal transmission of HIV-1.