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 antiretroviral (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.