# Transgender Youth and PrEP: PK, Safety, Uptake & Adherence

> **NIH NIH R01** · HEKTOEN INSTITUTE FOR MEDICAL RESEARCH · 2020 · $638,352

## Abstract

PROJECT SUMMARY/ABSTRACT
 Transgender women (TW) are one of the most vulnerable populations for acquiring HIV infection, and the
scant available data on transgender men (TM) suggests they are also at risk. TW have accounted for only
0.2% of all participants in bio-behavioral HIV prevention trials using pre-exposure prophylaxis (PrEP), and TM
have typically not been included. TW and TM adolescents have received even less attention in PrEP trials.
 Although tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), the FDA-approved PrEP drug, would not
be expected to interact with cross-sex hormone therapy (cs-HT; estradiol and testosterone) based on known
mechanisms and data from studies with hormonal contraceptives, there are no data that prove this. Given this
lack of data, TW and TM youth on cs-HT have decreased PrEP uptake and adherence due to concerns that
PrEP may reduce the effectiveness of cs-HT. To address these critical scientific gaps in PrEP safety for
transgender youth and to plan for appropriate implementation we propose the following study in 3 integrated
phases. In Phase 1, we will conduct a PK study exploring the interactions of cs-HT for both TW and TM on
TDF/FTC. Simultaneously, in Phase 2, we will collect ethnographic data via focus groups and in-depth
interviews to inform the development of a tailored gender-affirmative intervention to improve uptake and
adherence to PrEP in transgender youth. In Phase 3, we will conduct a small demonstration trial of PrEP use in
TW and TM youth, utilizing the ethnographically developed intervention to improve uptake and adherence,
while also monitoring renal and bone safety outcomes.
 The project has the following specific aims: Aim 1: To evaluate the differential PK of TDF/FTC in a cohort
of transgender youth on cs-HT by conducting a PK trial of daily TDF/FTC among 24 TW taking estradiol and 24
TM taking testosterone (ages 15-24 years) using video-based directly observed therapy (DOT) to insure daily
adherence and maximize drug exposure. Aim 2: To develop a culturally, developmentally, and gender-
affirmative intervention to increase uptake of and adherence to PrEP among TW and TM youth that is
grounded in theory (Information-Motivation-Behavioral Skills Model of Behavior Change, Gender Affirmation,
Empowerment Theory) and incorporates the PK data from Aim 1. We will conduct FGs with young TW (N=20-
30) and TM (N=20-30) and conduct IDIs with participants from the PK study (Total N=10-14). We will solicit
continuous input and feedback from TW and TM on the project's Youth Advisory Board. Aim 3: To conduct a
small randomized controlled trial within a PrEP demonstration project comparing the newly developed
intervention with standard of care (SOC) in TW (N=50) and TM (N=50) ages 15-24 years.

## Key facts

- **NIH application ID:** 9837489
- **Project number:** 5R01MH114753-03
- **Recipient organization:** HEKTOEN INSTITUTE FOR MEDICAL RESEARCH
- **Principal Investigator:** Sybil Hosek
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $638,352
- **Award type:** 5
- **Project period:** 2018-01-15 → 2022-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9837489

## Citation

> US National Institutes of Health, RePORTER application 9837489, Transgender Youth and PrEP: PK, Safety, Uptake & Adherence (5R01MH114753-03). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9837489. Licensed CC0.

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