Purpose: To Assess the impact of high and low in vivo estradiol exposure on PrEP (Pre-exposure prophylaxis) nucleotide concentrations in different cellular populations of the lower GI (gastrointestinal) tract and to quantify the relationship between estradiol, progesterone, and testosterone on PrEP nucleotide concentrations in rectal and peripheral blood mononuclear cells. As well as the relationship between estradiol, progesterone, and testosterone on PrEP concentrations in plasma. Participants: Healthy, cisgender female, volunteers, aged 18-49 inclusive on the date of screening with an intact gastrointestinal system and regular menstrual cycle. Procedures (methods): Participants will take a single daily dose of study drug for five days before each sampling visit. The visits will be scheduled during the early follicular phase of the menstrual cycle (approximately days 2-5 after the first day of menses, Visit 1) when estradiol is predicted to be the lowest and the late follicular phase (approximately days 12-15 after the first day of menses, Visit 2) when estradiol is predicted to be highest. Samples of blood, rectal cells, and rectal tissue will be collected at both Visits 1 and 2. All participants will complete a follow-up safety visit within 14 days of completing study sampling.
Participants will be enrolled, and sampling visits will be scheduled to correspond with their menstrual cycles. Five days prior to the first scheduled sampling visit, participants will come to the clinic to have a repeat urine pregnancy test performed to verify eligibility. After verification, participants will be given a single dose of the study medication, Truvada®. Study staff will witness the dose and assess for any adverse reactions post dose. Participants will be sent home with a supply of 4 additional doses of Truvada® for them to take at scheduled times for the next 4 days with study staff observing via video call. Study staff will assess for adverse events during each dosing call. Starting 72 hours before each sampling visit, participants will be required to switch to a low fiber diet and abstain from inserting anything rectally. Twelve hours prior to each sampling visit, participants will be required to abide by a clear liquid diet. Participants will be seen as an outpatient at the Clinical Translational Research Center (CTRC) at University of North Carolina at Chapel Hill (UNC) for these sampling visits. At these visits, participants will have blood samples drawn to measure peripheral blood mononuclear cells and serum hormone concentrations. Participants will also have rectal cells collected via cytobrush and rectal tissue collected via rectal biopsy. After all samples have been collected, participants will be evaluated for adverse events and be discharged. Within 14 days of completion of the second sampling visit, for a follow-up visit. At this visit, blood will be obtained to check safety labs.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
10
Once daily dose of the combo tab x 5 days pre-sampling
Once daily dose of the combo tab x 5 days pre-sampling
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Average Tenofovir Diphosphate Concentrations in Mixed Rectal Cells During the Early (Low Estradiol) Follicular Phases of the Menstrual Cycle.
Average tenofovir diphosphate concentrations measured in mixed rectal cells collected via cytobrush during the early (low estradiol) follicular phases of the menstrual cycle reported in Fmol/million cells.
Time frame: Days 2-5
Average Tenofovir Diphosphate Concentrations Measured in Mixed Rectal Cells During the Late (High Estradiol) Follicular Phases of the Menstrual Cycle.
Average tenofovir diphosphate concentrations measured in mixed rectal cells collected via cytobrush during the late (high estradiol) follicular phases of the menstrual cycle reported in Fmol/million cells
Time frame: Days 12-15
Average Emtricitabine Triphosphate Concentrations Measured in Mixed Rectal Cells During the Early (Low Estradiol) Follicular Phases of the Menstrual Cycle.
Average emtricitabine triphosphate concentrations measured in mixed rectal cells collected via cytobrush during the early (low estradiol) follicular phases of the menstrual cycle reported in Fmol/million cells.
Time frame: Days 2-5
Average Emtricitabine Triphosphate Concentrations Measured in Mixed Rectal Cells During the Late (High Estradiol) Follicular Phases of the Menstrual Cycle.
Average emtricitabine triphosphate concentrations measured in mixed rectal cells collected via cytobrush during the late (high estradiol) follicular phases of the menstrual cycle reported in Fmol/million cells.
Time frame: Days 12-15
Average Estradiol Concentrations in Serum.
Average estradiol concentrations in serum reported in pg/mL
Time frame: Day 5
Average Progesterone Concentrations in Serum.
Average progesterone concentrations in serum measured in ng/mL.
Time frame: Day 5
Average Testosterone Concentrations in Serum.
Average testosterone concentrations in serum measured in ng/mL
Time frame: Day 5
Average Tenofovir Diphosphate Concentrations in Peripheral Blood Mononuclear Cells.
Average tenofovir diphosphate concentrations in peripheral blood mononuclear cells reported in Fmol/million cells.
Time frame: Day 5
Average Emtricitabine Concentrations in Peripheral Blood Mononuclear Cells.
Average emtricitabine concentrations in peripheral blood mononuclear cells reported in Fmol/million cells.
Time frame: Day 5
Average Tenofovir Concentrations in Plasma.
Average tenofovir concentrations in plasma reported in ng/mL.
Time frame: Day 5
Average Emtricitabine Concentrations in Plasma.
Average emtricitabine concentrations in plasma reported in ng/mL.
Time frame: Day 5
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