Pharmacokinetics of maraviroc in plasma and breastmilk in a treatment-experienced perinatally HIV-1-infected woman

Maraviroc (MVC), a C-C chemokine receptor type five (CCR5) antagonist, was approved as part of combination antiretroviral therapy (cART) in 2007, for use in treatment-experienced adults infected with CCR5tropic HIV-1 [1]. Whilst, with current treatment strategies, such as maternal cART, low rates of mother-to-child transmission (MTCT) have been reported, in high-income countries, breastfeeding is not recommended because of the potential MTCT risk. However, since 2017, European [2] and United States [3] guidelines have acknowledged that some HIV-infected women may wish to breastfeed, and should be given appropriate support in this decision. Whilst data exist describing the transfer of NRTI, NNRTI, and protease inhibitors to breastfed infants [4,5], the pharmacokinetics and safety of MVC in lactating women and their breastfed infants have not been reported. Here, we present the first case of MVC in a breastfeeding mother.