Etravirine Pharmacokinetics and HIV Viral Load in Breast Milk and Plasma

HIV positive pregnant women who receive potent combination antiretroviral therapy over at
least the last trimester of pregnancy, and who have proper obstetric interventions and are
able to avoid breast feeding, decrease the risk of having an infected infant to about 1%.
Breast milk HIV-1 RNA (cell free) viral load is significantly associated with breast milk
transmission, and a 2-fold increased risk of transmission associated with every 10-fold
increase in breast milk viral load has been reported. In addition, cell associated virus
(HIV DNA) was associated with a significant increase in risk of transmission independent of
the level of cell-free viral RNA.

However, multiple studies of HIV positive women giving birth have shown that exclusive
breast-feeding carries a much lower risk of HIV transmission than mixed breast-feeding
(defined as breast milk along with complementary food, other milk, and/or infant formula).
The proposed study will measure the ARV drug etravirine concentrations in blood and breast
milk in postpartum HIV positive women on HAART therapy. The short-term goal is to determine
how much etravirine penetrates into breast milk, and whether it leads to undetectable HIV
viral load in the breast milk and therefore has the potential to decrease the risk of
transmission of HIV through breast milk. The long term goal is to see if breast milk HIV
levels can be lowered sufficiently to prevent maternal to child transmission (MTCT) of HIV
in infants receiving only breast feeding in resource poor areas.