Transfer of antiretroviral drugs into breastmilk: a prospective study from the Swiss Mother and Child HIV Cohort Study. Journal of Antimicrobial Chemotherapy
Aebi-Popp et al. studied women living with HIV who decided to breastfeed their infants while taking antiretroviral therapy (ART) and aimed to quantify ART drug levels in breastmilk and the infant’s plasma to evaluate the potential for drug toxicity.
In accordance with the Swiss recommendations, breastfeeding was deemed possible for women with good adherence to ART and an HIV viral load <50 cp/mL throughout pregnancy, and follow-up visits were performed monthly during breastfeeding. ART drug quantification was performed in maternal plasma and mild samples, and if possible, a blood sample was also collected from the infant. No HIV post-exposure prophylaxis was administered to the neonates.
The study included 21 mothers who delivered a child between January 2019 and February 2021 and who decided to breastfeed their infant. No HIV transmission from the mother to the child occurred. The highest milk/plasma ratios were observed for NRTI (4.09 for tenofovir alafenamide, 3.92 for emtricitabine, 3.74 for lamivudine, and 1.03 for abacavir), followed by NNRTI (1.08 for rilpivirine, 0.86 for efavirenz, and 0.70 for nevirapine). The lowest passage in milk was observed for INSTI (milk/plasma ratio 0.01 for bictegravir and 0.04 for dolutegravir), with raltegravir once daily being an exception (milk/plasma ratio 0.96). Despite high levels of NRTI in breastmilk, their blood levels in breastfed infants were very low and did not exceed 5% of a daily infant ART dose.
In summary, the present study nicely outlined the variability of ART transfer into breast milk in women living with HIV, with NRTI and NNRTI showing the highest levels. The daily infant ART dose from breastfeeding remained very low, and well below the threshold of 10%, which is considered safe for infants. These findings add crucial information for the shared-decision making process involved for treatment-adherent women who wish to breastfeed their infants.