When taken by breastfeeding mothers, the antiretroviral drugs tenofovir and emtricitabine appear to be present at low concentrations in breast milk and in the bloodstream of their infants. This research, described by Kenneth Mugwanya, University of Washington, Seattle, and colleagues in a Research Article in PLOS Medicine, suggests that there is a low risk of side effects in breastfed infants exposed to the drugs.
Pre-exposure prophylaxis (PrEP) employs antiretroviral drugs to prevent HIV infection, and is generally used in people at high risk of being infected with HIV. However, there is little scientific evidence available to support the safety of PrEP in women who are breastfeeding, where drugs and their metabolites could be transmitted to infants. Such women may be at high risk of HIV infection in some African countries, for example, and in the event of infection there is the added risk of HIV transmission from mother to child.
Mugwanya and colleagues studied 50 pairs of mothers and infants in Kenya and Uganda, who were uninfected by HIV, up to 24 weeks after birth. The mothers took the combination oral PrEP drug emtricitabine-tenofovir disoproxil fumarate for 10 days, and drug concentrations were measured in breast milk and infant blood. Although the study involved a small group of women and infants, was of short duration and limited to a single blood draw from infants, the findings indicate that drug concentrations are low in breast milk and in infants' blood, and that the risk of adverse events is therefore likely to be small.
In a Perspective discussing the research, Lynne Mofenson, Elizabeth Glaser Pediatric AIDS Foundation, Washington, D.C., argues in favour of extending implementation of PrEP with tenofovir to pregnant and breastfeeding women who are at high risk of HIV infection.
This work was supported by the Bill and Melinda Gates Foundation (OPP47674) and the US National Institutes of Health (R01MH095507). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
The authors of this manuscript have the following competing interests: FTC-TDF was donated by Gilead Sciences. CWH reports a prior contract from Gilead Sciences outside the submitted work and a patent pending, both managed by Johns Hopkins. MM has grant funding via the NIH. GJS has research grants from NIH (unrelated), CDC (unrelated), Thrasher Foundation (unrelated), Bill and Melinda Gates Foundation (sponsor), royalties from UpToDate (unrelated), and salary support from the University of Washington. All authors declare no other conflicts of interest.
Article: Pre-exposure Prophylaxis Use by Breastfeeding HIV-Uninfected Women: A Prospective Short-Term Study of Antiretroviral Excretion in Breast Milk and Infant Absorption, Mugwanya KK, Hendrix CW, Mugo NR, Marzinke M, Katabira ET, Ngure K, et al., PLOS Medicine, doi:10.1371/journal.pmed.1002132, published 27 September 2016.
Perspective: Tenofovir Pre-exposure Prophylaxis for Pregnant and Breastfeeding Women at Risk of HIV Infection: The Time is Now, Mofenson LM, PLOS Medicine,doi:10.1371/journal.pmed.1002133, published 27 September 2016.