This study will establish benchmarks of TFV-DP concentrations as measures of adherence following daily dosing with Tenofovir Alafenamide (TAF) compared with Tenofovir Disoproxil Fumarate (TDF) during pregnancy and postpartum. Study Investigators will recruit from an ongoing observational cohort study in Cape Town, South Africa, PrEP-PP (recruitment ongoing through July, 2021; NIMH R01MH116771; PI Coates & Myer). Findings form this PK sub-study will be used to inform future PrEP in pregnancy and postpartum studies and develop benchmarks of the relative PK between TDF and TAF.~Study aims. (1) To establish benchmarks of TFV-DP concentrations as measures of adherence following daily dosing with TAF vs TDF in pregnancy and again in postpartum; (2) To compare the difference of TFV-DP within TDF and TAF for pregnancy vs. postpartum, and to establish adherence benchmarks of levels of TFV in breastmilk in postpartum women and compare with TDF sample.~The study will take place in an urban township in Cape Town (Gugulethu) with high HIV incidence that spans the different socioeconomic, cultural, and ethnic groups in South Africa. We selected this community because of the high HIV prevalence there in pregnant and breastfeeding women, and because of the high number of mothers visiting every month for ANC and labour/delivery.
This study will establish benchmarks of TFV-DP concentrations as measures of adherence following daily dosing with Tenofovir Alafenamide (TAF) compared with Tenofovir Disoproxil Fumarate (TDF) during pregnancy and postpartum. Study Investigators will recruit from an ongoing observational cohort study in Cape Town, South Africa, PrEP-PP (recruitment ongoing through July, 2021; NIMH R01MH116771; PI Coates & Myer). Findings form this PK sub-study will be used to inform future PrEP in pregnancy and postpartum studies and develop benchmarks of the relative PK between TDF and TAF.