I-BrEATHe - Interactions Between Antiretrovirals And Transgender Hormones

Detailed Summary

Truvada (Emtricitabine or FTC and tenofovir disoproxil fumarate or TDF) has been approved for HIV prevention since 2012. Drug concentrations after receipt of oral Truvada for HIV Pre Exposure Prophylaxis (or PrEP) appeared to be lower in transgender women compared to Men who Have Sex with Men (MSM) in the iPrEx study, the landmark study of PrEP for HIV prevention. Concentrations were especially low among transgender women (TGW) reporting use of feminizing hormones. Reasons for the lower drug concentrations may be behavioral or biomedical, or a combination of both. While there are no systemic drug-drug interactions between TDF and oral contraception, there are known interactions involving these classes of medications with drug transporters that could affect drug concentrations in target tissues. Drug-drug interactions with natural estrogens and anti-androgenic agents used for gender affirming hormone therapy among transgender women have not been studied, neither have interactions between emtricitabine and female hormones. Concerns about the impact of PrEP on gender affirming hormone therapy is the main barrier for uptake of PrEP among transgender women. In addition, very little is known about TDF/FTC pharmacokinetics in transgender men using testosterone hormonal therapy. Drug-drug interactions with masculinizing hormones have never been properly investigated as trans gender men have not been formally involved in PrEP clinical trials or demonstrations projects.This small study will assess pharmacokinetic drug-drug interactions between tenofovir disoproxil fumarate/emtricitabine and cross-sex hormone therapy. The I-BrEATHe study is a substudy of the Triumph study, a culturally-relevant community-led PrEP demonstration project in transgender communities. The I- BrEATHe pharmacokinetic substudy will provide Truvada daily using directly observed therapy in 24 transgender women and 24 transgender men over a one month period, and will measure drug and hormone therapy levels in blood collected from participants.

Study Details

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Interventions