fWe evaluated the in vivo pharmacokinetics and used a complementary ex vivo coculture assay to determine the pharmacodynamics of IQB3002 gel containing 1% IQP-0528, a nonnucleoside reverse transcriptase inhibitor (NNRTI), in rhesus macaques (RM). The gel (1.5 ml) was applied vaginally to 6 simian-human immunodeficiency (SHIV)-positive female RM. Blood, vaginal fluids, and rectal fluids were collected at 0, 1, 2, and 4 h. RM were euthanized at 4 h, and vaginal, cervical, rectal, and regional lymph node tissues were harvested. Anti-human immunodeficiency virus (HIV) activity was evaluated ex vivo by coculturing fresh or frozen vaginal tissues with activated human peripheral blood mononuclear cells (PBMCs) and measuring the p24 levels for 10 days after an HIV-1 Ba-L challenge. The median levels of IQP-0528, determined using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) methods, were between 10 4 and 10 5 ng/g in vaginal and cervical tissue, between 10 3 and 10 4 ng/g in rectal tissues, and between 10 5 and 10 7 ng/ml in vaginal fluids over the 4-h period. The vaginal tissues protected the cocultured PBMCs from HIV-1 infection ex vivo, with a viral inhibition range of 81 to 100% in fresh and frozen tissues that were proximal, medial, and distal relative to the cervix. No viral inhibition was detected in untreated baseline tissues. Collectively, the median drug levels observed were 5 to 7 logs higher than the in vitro 50% effective concentration (EC 50 ) range (0.21 ng/ml to 1.29 ng/ml), suggesting that 1.5 ml of the gel delivers IQP-0528 throughout the RM vaginal compartment at levels that are highly inhibitory to HIV-1. Importantly, antiviral activity was observed in both fresh and frozen vaginal tissues, broadening the scope of the ex vivo coculture model for future NNRTI efficacy studies.
HIV-1 microbicide clinical trials have primarily been focused on vaginal gels as a topical preexposure prophylaxis (PrEP) modality to prevent virus acquisition through vaginal intercourse in at-risk women. However, several behavioral studies and clinical trial reports have shown that women also engage in unprotected receptive anal intercourse (RAI), with the highest rates of RAI being found among female sex workers and patients at sexually transmitted infection clinics (1-9). In addition, a recent metaanalysis demonstrated that the estimated per-act human immunodeficiency (HIV) transmission risk (per 10,000 exposures) for RAI is 138, compared to 11, 8, and 4 for insertive anal intercourse, receptive penile-vaginal intercourse, and insertive penile-vaginal intercourse, respectively (10). The risk of HIV acquisition via unprotected RAI may be further exacerbated through the improper use of vaginal microbicide gels or high osmolality personal lubricants in the rectal compartment, which have been shown to cause cellular inflammation and epithelial damage (11-19). These studies collectively highlight a need for a microbicide formulation that is specifically designed for safe application in both the vaginal and rectal comp...