A Randomized, Comparative Safety Study of a Prefilled Plastic and User-Filled Paper Applicator With Candidate Microbicide Tenofovir 1% Gel

BACKGROUND: A bridging study was performed to compare the safety, dose delivery, and acceptability of a prefilled plastic and user-filled paper applicator to assess whether a low-cost, user-filled, paper applicator could serve as a delivery option for tenofovir (TFV) 1% vaginal microbicide gel. METHODS: The study used a randomized crossover design with 25 healthy women randomized to begin with the prefilled or user-filled applicator. Within each study arm, participants delivered two 4.0-mL doses of TFV 1% gel vaginally for 7 days, with one dose delivered at the clinic each morning and a second dose delivered at home each evening. To assess the primary objective, applicator safety, colposcopy examinations were performed at 2 time points in each study arm. RESULTS: There were no colposcopic findings or adverse events attributable to either applicator. One case of vulvovaginal candidiasis was considered possibly related to gel use. On average, the user-filled applicator delivered 96% of the target dose, with 85% of doses falling within ± 10% of the average dose volume. Participants found both applicators comparable for ease of use, insertion, and dispensing gel, with 60% of participants preferring the user-filled applicator. CONCLUSIONS: This study suggests that both applicators are safe, and most women delivered TFV with the user-filled applicator as directed. Participants found both applicators acceptable, with a slight majority preferring the user-filled applicator. Incorporating a low-cost, user-filled, paper applicator to deliver TFV could help reduce costs and improve access to TFV 1% gel, especially in resource-limited settings heavily impacted by HIV.