Vaginal microbicides for the prevention of HIV transmission maybe an important option for protecting women from infection.Incorporation of dapivirine, a lead candidate nonnucleoside reversetranscriptase inhibitor, into intravaginal rings (IVRs) for sustainedmucosal delivery may increase microbicide product adherence andefficacy compared with conventional vaginal formulations. Twentyfourhealthy HIV-negative women 18–35 years of age were randomlyassigned (1:1:1) to dapivirine matrix IVR, dapivirine reservoir IVR,or placebo IVR. Dapivirine concentrations were measured in plasmaand vaginal fluid samples collected at sequential time points over the33-day study period (28 days of IVR use, 5 days of follow-up). Safetywas assessed by pelvic/colposcopic examinations, clinical laboratorytests, and adverse events. Both IVR types were safe and well toleratedwith similar adverse events observed in the placebo and dapivirinegroups. Dapivirine from both IVR types was successfully distributedthroughout the lower genital tract at concentrations over 4 logs greaterthan the EC50 against wild-type HIV-1 (LAI) in MT4 cells. Maximumconcentration (Cmax) and area under the concentration–time curve(AUC) values were significantly higher with the matrix than reservoirIVR. Mean plasma concentrations of dapivirine were ,2 ng/mL.These findings suggest that IVR delivery of microbicides is a viableoption meriting further study.Key Words: dapivirine, HIV, intravaginal ring, microbicide,pharmacokinetics, prevention
Development of pre-clinical and clinical models to predict the efficacy and safety of vaginal microbicides