Vaginal Microbiota and Mucosal Pharmacokinetics of Tenofovir in Healthy Women using a 90 day Tenofovir/Levonorgestrel Vaginal Ring

A relationship between the vaginal microbiota and tenofovir (TFV) concentrations and activity after topical administration has been previously reported. CONRAD A15-138 was a randomized, placebo-controlled Phase I study aimed at characterizing the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of TFV and levonorgestrel (LNG) administered through a vaginal ring (IVR) for 90d. The project focuses on the interaction with the vaginal microbiota. The TFV/LNG IVR had no adverse impact on the vaginal microbiota. Vaginal microbiota, and in particular CST IV, possibly through increased vaginal pH, impacted in vivo TFV release and cervicovaginal (CV) PK, but both PK and PD data suggest CV protection against HIV-1.