Simultaneous in vivo Pharmacokinetics and Pharmacodynamics of TDF Intravaginal Ring during High-dose Vaginal SHIV Challenge in Pigtail Macaques

The demonstration of complete protection of macaques in a repeated low dose virus challenge by a tenofovir disoproxil fumarate (TDF) intravaginal ring (IVR) and the success of the dapivirine IVR in clinical trials highlighted the potential of IVRs as pre-exposure prophylaxis against HIV. Efficacy of TDF ring was not investigated in sexually active women. Our understanding of the mechanisms of protection is limited. To address this knowledge gap, we performed simultaneous pharmacokinetic and pharmacodynamic analysis of a TDF-IVR at the site of SIV challenge in pigtail macaques at the anatomical and cellular level. Specifically, we challenged TDF-IVR administered pigtail macaques with a single high dose of a non-replicative SIV-based vector containing a dual reporter system that helped us to identify the earliest targets of SIV infection within the mucosa. Two and three days after challenge, the macaques were euthanized and tenofovir (TFV) concentrations were measured in the female reproductive tract (FRT) by HPLC-MS/MS to correlate drug concentrations and SIV-vector transduction efficiency. TFV formed a gradient through the mucosal tissue, with the highest concentrations near the ring, in the upper vagina and endocervix. Despite this, several transduction events were identified with the most common sites being in the ovaries. Moreover, proviral DNA was detected in the cervix and vagina. Thus, our studies demonstrate an uneven distribution of TFV in the FRT of macaques after release from a TDF-IVR that leads to incomplete FRT protection from high viral dose challenge.

Segmented intravaginal ring for the combination delivery of hydroxychloroquine and anti-CCR5 siRNA nanoparticles as a potential strategy for preventing HIV infection

Vaginal drug delivery has been shown to be a promising strategy for the prevention of sexually transmitted infections. Therapy delivered at the site of infection has many advantages including improved therapeutic efficacy, reduction in systemic toxicity, and reduced potential for development of drug resistance. We developed a “smart” combination intravaginal ring (IVR) that will (1) provide continuous release of hydroxychloroquine (HCQ) to induce T cell immune quiescence as the first-line of defense and (2) release nanoparticles containing anti-CCR5 siRNA only during sexual intercourse when triggered by the presence of seminal fluid as the second-line of defense. The IVR was capable of releasing HCQ over 25 days with a mean daily release of 31.17 ± 3.06 µg/mL. In the presence of vaginal fluid simulant plus seminal fluid simulant, over 12 × more nanoparticles (5.12 ± 0.9 mg) were released over a 4-h period in comparison to IVR segments that were incubated in the presence of vaginal fluid simulant alone (0.42 ± 0.19 mg). Anti-CCR5 siRNA nanoparticles were able to knockdown 83 ± 5.1% of CCR5 gene expression in vitro in the CD4+ T cell line Sup-T1. The IVR system also demonstrated to be non-cytotoxic to VK2/E6E7 vaginal epithelial cells. Graphical abstract

4109 Acceptability of a Tenofovir Disoproxil Fumarate Intravaginal Ring for Human Immunodeficiency Virus Pre-Exposure Prophylaxis Among Sexually Active Women

OBJECTIVES/GOALS: Vaginal ring delivery of antiretroviral drugs may provide protection against acquisition of HIV-1 when used as pre-exposure prophylaxis. As part of a randomized placebo-controlled safety trial of a tenofovir disoproxil fumarate (TDF) intravaginal ring (IVR), we assessed product acceptability through surveys of 17 women after continuous ring use. METHODS/STUDY POPULATION: Sexually active, HIV negative women between the ages of 18 and 45 were enrolled to investigate the safety and pharmacokinetics of three months of continuous TDF IVR use. The study was designed to include 40 US participants randomly assigned (3:1) to a TDF or placebo IVR. Twelve were randomized to TDF and five were assigned to the placebo group before the study was electively discontinued due to development of vaginal ulcerations in eight women in the TDF group. Acceptability data regarding TDF and placebo ring use was gathered via self-administered, computer-based questionnaires at the one- and three-month study visits. Participants were asked about overall attitudes and feelings regarding the TDF and placebo IVR, vaginal changes associated with ring use, and their experiences with ring use during menses and with sex. RESULTS/ANTICIPATED RESULTS: The mean age of participants was 30 years (range 18 - 42). Sixteen of 17 (94%) participants completed all study questions at both visits. When asked about ring likeability at one-month, 12 of 16 (75%) women reported overall liking the ring, including 5 of 8 (63%) who developed ulcerations. Vaginal changes described during ring use included 8 participants who indicated that the “vagina was wetter” and 2 who reported that the “vagina was drier.” Additionally, 10 of 12 (83%) who had their period during the first month of the study were not bothered by ring use during menses, and 11 of 16 (69%) stated that the ring was not bothersome with use during sex. When asked at the three-month visit, most reported that they would prefer to wear the ring rather than use a condom during sex, however, condom use was low at baseline in this population. DISCUSSION/SIGNIFICANCE OF IMPACT: Despite unanticipated ulcers, the IVRs were acceptable, especially when used with menses and during sex. Regardless of the group assigned or vaginal changes experienced, and even amongst those who developed ulcerations, the women had positive attitudes towards the ring, which is promising for future use of vaginal rings as a method for HIV prevention.