Antiretroviral Therapies Delivered by Pod-Intravaginal Rings for HIV-1 Prevention
Drug concentration of ARTs via intravaginal ring delivery exceeded concentrations achieved by highly protective oral dosing, suggesting that efficacy for vaginal HIV PrEP is achievable.
Pod-intravaginal rings (IVR) are innovative devices that appear to be safe and well tolerated for delivering different regimens of antiretroviral therapies (ARTs) for pre-exposure human immunodeficiency virus (HIV) prophylaxis, according to a pilot phase I study published in PLoS Medicine.1
Associated with better adherence compared with oral or vaginal film/gel regimens, studies have demonstrated that intravaginal ring delivery of an ART agent can reduce the risk for acquiring HIV by as much as 56% in highly adherent users.2,3 Composed of an elastomer scaffold that can hold up to 10 polymer-coated drug cores, the pod- intravaginal ring is distinct from other intravaginal devices as drug release from each pod can be controlled independently.1
Researchers performed an exploratory open-label clinical trial to evaluate the safety, pharmacokinetics, and user perceptibility of pod-intravaginal rings in 6 women delivering 3 different ART regimens. Women received 7 days of continuous tenofovir disoproxil fumarate pod-intravaginal ring use followed by a washout phase and then 7 days of continuous tenofovir disoproxil fumarate-emtricitabine pod-intravaginal ring use. After a 3-month pause, women received 7 days of continuous tenofovir disoproxil fumarate-emtricitabine-maraviroc use. The researchers found that all 3 pod-intravaginal rings maintained high controlled ART drug concentrations in cervicovaginal fluid while leading to low systemic exposures, and cercovaginal fluid levels decreased sharply after pod-intravaginal ring removal. Acceptability was high for all 3 products and there were no serious adverse events. The majority of the 26 adverse events reported were itching, discharge, and discomfort.
“In conclusion, a crossover phase 1 clinical trial sequentially evaluated tenofovir disoproxil fumarate, tenofovir disoproxil fumarate-emtricitabine, and tenofovir disoproxil fumarate-emtricitabine-maraviroc pod-intravaginal rings and demonstrated that the devices exhibited favorable safety and pharmacokinetic profiles across all three treatment periods.” noted the study investigators.1 Thus, longer and larger clinical trials should be conducted.
- Vincent KL, Moss JA, Marzinke MA, et al. Safety and pharmacokinetics of single, dual, and triple antiretroviral drug formulations delivered by pod-intravaginal rings designed for HIV-1 prevention: a Phase I trial. PLoS Med. 2018;15(9):e1002655.
- Baeten JM, Palanee-Phillips T, Brown ER, et al. Use of a vaginal ring containing dapivirine for HIV-1 prevention in women. N Engl J Med. 2016;375:2121-2132.
- Guthrie KM, Vargas S, Shaw JG, et al. The promise of intravaginal rings for prevention: user perceptions of biomechanical properties and implications for prevention product development. PLoS ONE. 2015;10(12):e0145642.