The Women TAF-FTC Benchmark Study

Safety and Pharmacokinetics of TAF-FTC Pre-exposure Prophylaxis in Kenyan Cisgender Women

The study seeks to assess the safety of and define blood and tissue benchmark concentrations of tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP) in cisgender women using directly observed oral pre-exposure prophylaxis (PrEP) therapy with tenofovir alafenamide-emtricitabine (TAF-FTC). Cisgender women will be randomly assigned to receive varying frequencies of weekly PrEP doses and followed for up to 18 weeks.These data will help accurate interpretation of efficacy results obtained in HIV prevention trials and programs in cisgender women.

Study Overview

• Status: Completed
• Conditions: HIV Infections
• Intervention / Treatment: Drug: co-formulated 25mg TAF/ 200mg FTC

Detailed Description

This is an open-label, randomized, three-arm, directly observed therapy (DOT), pharmacokinetics study. HIV-uninfected non-pregnant cisgender women at low risk for HIV acquisition will be randomly assigned to 1 of 3 dosing frequencies of DOT with tenofovir alafenamide-emtricitabine (TAF-FTC) oral PrEP, to help differentiate poor and moderate from perfect adherence. The primary objectives of the study are:

1. To describe the safety of TAF-FTC-based PrEP in HIV-uninfected cisgender women.
2. To define expected blood concentrations and dose-proportionality specific to cisgender women for tenofovir-diphosphate (TFV-DP) in dried blood spots (DBS) and peripheral blood mononuclear cells (PBMCs) using directly observed therapy of TAF-FTC at 2, 4, and 7 doses per week, representing poor, moderate, and perfect adherence, respectively.
3. To establish a model to predict adherence rate to TAF-FTC by level of TFV-DP in DBS for cisgender women. HIV-uninfected non-pregnant cisgender women will be randomly assigned to 1 of 3 dosing frequencies of directly observed therapy of TAF-FTC oral PrEP: 2, 4, or 7 doses/week to differentiate poor and moderate from perfect adherence.

The study will be the first to define TAF-FTC-based PrEP adherence-blood concentration thresholds for African cisgender women, a priority population for HIV prevention. The findings will guide accurate interpretation of safety, adherence, and efficacy of planned or ongoing HIV prevention trials in African women.

• Study Type: Interventional
• Enrollment (Actual): 54
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• Kenya
  • Thika, Kenya
    • Kenya Medical Research Institute - Partners in Health Research and Development

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 30 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age ≥18 and ≤30 years old
• Willing to undergo urine pregnancy tests
• Has understood the information provided and has provided written informed consent before any study-related procedures are performed.
• HIV uninfected based on negative HIV rapid tests, according to Kenyan national algorithm
• Normal renal function (estimated glomerular filtration rate >60 mL/min)
• Hepatitis B surface Ag negative
• No active clinically significant medical or psychiatric conditions that, in the opinion of the investigators, would interfere with study participation
• Lack of severe anemia (Hemoglobin >10 g/dL)
• Willing to use DOT and come to clinic frequently for DOT PrEP for at least 10 weeks
• Willing to have home visits for follow up
• Has access to an active smartphone to allow off-site observation of dosing if unable to come to the clinic or as determined by the study staff, the participant resides in close location to clinic to permit home visit if unable to come to the clinic. i.e., potential participants without a smartphone may be enrolled in the study if investigator determines that the participant resides within reasonable distance from the clinic that would permit home visit id the participant misses their visit.
• Intention to stay within the study site's catchment area for at least 10 weeks.
• Resides or works in catchment area with high speed internet coverage to permit video streaming
• Not pregnant or breast feeding
• Willing to use effective contraception during the study period.
• At low risk for HIV. In Kenya, national guidelines define substantial risk for HIV and recommend PrEP be an option for individuals reporting: partner of HIV-infected person not on ART or on ART for <6 months, >1 partner of unknown status, transactional sex, recent STI, recurrent PEP use, inconsistent condom use, or injection drug use. So, non-pregnant cisgender women reporting any of these factors will not be eligible for the study but will be linked for PrEP at clinic of choice including at Thika Site itself.
• Willing to be randomized to non-daily PrEP and come to clinic frequently for DOT PrEP
• Willingness and ability to be abstinent for at least 7 days after each vaginal biopsy visit.

Exclusion Criteria:

• Inability to give informed consent
• Positive screening HIV+ as determined by standard rapid serologic assays or suspected acute HIV infection in the opinion of the clinician. (example signs and symptoms of acute HIV infection include combinations of fever, headache, fatigue, arthralgia, vomiting, myalgia, diarrhea, pharyngitis, rash, night sweats, and adenopathy cervical or inguinal)
• Positive HBV surface antigen test at screening
• Calculated creatinine clearance <60 ml/min.
• Any laboratory value or uncontrolled medical conditions that, in the opinion of the investigators, would interfere with the study conditions such as, heart disease and/or cancer.
• Prohibited concomitant medications are: investigational agents (within 30 days of enrollment), aminoglycosides, ganciclovir/valganciclovir, chronic high-dose acyclovir/valacyclovir (>800mg acyclovir or >500mg valacyclovir for >7 days), cyclosporine, amphotericin B, foscarnet, and cidofovir, and products with same or similar active ingredients as the study medications including TAF®, TRUVADA®, ATRIPLA®, COMPLERA®, EMTRIVA®, VIREAD®; or drugs containing lamivudine or adefovir, which are close analogs of FTC and tenofovir, respectively.
• Current or past use of PrEP (pre-exposure prophylaxis)
• Not willing to have home visits
• Pregnancy or plan to become pregnant in the next 6 months or unwillingness to use birth control
• Current breastfeeding
• High risk of HIV infection (for example: sexually active with an HIV infected partner; engages in condomless intercourse with HIV-infected partners or partner of unknown status during the study; females who exchange sex for money, shelter, or gifts; active injection drug use or during the last 12 months; newly diagnosed sexually transmitted infections in last 6 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Perfect Adherence; Cisgender women will receive a single tablet of coformulated 25 mg TAF/ 200mg FTC once daily (7 doses per week).	Drug: co-formulated 25mg TAF/ 200mg FTC; Participants will be randomized into 1 of 3 groups to receive a controlled number of doses of a single tablet of co-formulated 25 mg TAF/ 200mg FTC; Other Names: Descovy
Experimental: Moderate Adherence; Cisgender women will receive a single tablet of coformulated 25 mg TAF/ 200mg FTC 4 times per week	Drug: co-formulated 25mg TAF/ 200mg FTC; Participants will be randomized into 1 of 3 groups to receive a controlled number of doses of a single tablet of co-formulated 25 mg TAF/ 200mg FTC; Other Names: Descovy
Experimental: Poor Adherence; Cisgender women will receive a single tablet of coformulated 25 mg TAF/ 200mg FTC twice per week	Drug: co-formulated 25mg TAF/ 200mg FTC; Participants will be randomized into 1 of 3 groups to receive a controlled number of doses of a single tablet of co-formulated 25 mg TAF/ 200mg FTC; Other Names: Descovy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency of Adverse Events	The frequency of graded adverse events by arm, including emergent HIV infection during the study period.	Assessed through the 10 week DOT dosing period
Concentrations of Tenofovir Disphosphate (TFV-DP) and Emtricitabine Triphosphate (FTC-TP) Measured at Ten Weeks in Dried Blood Spots (DBS)	TFV-DP and FTC-TP concentrations observed in dried blood spots (DBS) after ten weeks of directly observed therapy with TAF-FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively.	Assessed at week 10
Concentrations of Tenofovir Disphosphate (TFV-DP) and Emtricitabine Triphosphate (FTC-TP) Measured at Four Weeks in Peripheral Blood Mononuclear Cells (PBMCs)	Steady-state TFV-DP and FTC-TP concentrations observed in peripheral blood mononuclear cells (PBMCs) after ten weeks of directly observed therapy with TAF-FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively.	Assessed at week 4
Fitted Steady-state TFV-DP Concentrations in Dried Blood Spots (DBS)	Fitted steady-state TFV-DP concentrations after ten weeks of directly observed therapy with TAF-FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively.	Assessed through 10 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Steady state concentrations of tenofovir for different dosing patterns of DOT TAF/FTC PrEP	Measured in plasma and vaginal tissue	Assessed through 10 weeks
Steady state concentrations of TFV-DP for different dosing patterns of DOT TAF/FTC PrEP measured in vaginal tissue	Measured in vaginal tissue	Assessed through 10 weeks

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: University of Colorado, Denver; Gilead Sciences; Kenya Medical Research Institute
• Investigators: Principal Investigator: Peter L Anderson, PharmD, University of Colorado, Denver; Principal Investigator: Kenneth K Mugwanya, MBChB, MS, PhD, University of Washington

Study record dates

Study Major Dates

• Study Start (Actual): March 28, 2023
• Primary Completion (Actual): December 19, 2023
• Study Completion (Actual): December 19, 2023

Study Registration Dates

• First Submitted: November 18, 2021
• First Submitted That Met QC Criteria: November 18, 2021
• First Posted (Actual): December 2, 2021

Study Record Updates

• Last Update Posted (Estimated): October 27, 2025
• Last Update Submitted That Met QC Criteria: September 30, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: HIV; Kenya; Pre-exposure Prophylaxis; Descovy
• Additional Relevant MeSH Terms: Blood-Borne Infections; Urogenital Diseases; Genital Diseases; Immune System Diseases; Infections; RNA Virus Infections; Virus Diseases; Communicable Diseases; Sexually Transmitted Diseases, Viral; Sexually Transmitted Diseases; Lentivirus Infections; Retroviridae Infections; Immunologic Deficiency Syndromes; HIV Infections; Molecular Mechanisms of Pharmacological Action; Anti-Infective Agents; Antiviral Agents; Reverse Transcriptase Inhibitors; Nucleic Acid Synthesis Inhibitors; Enzyme Inhibitors; Anti-HIV Agents; Anti-Retroviral Agents; emtricitabine tenofovir alafenamide; Racivir
• Other Study ID Numbers: STUDY00014075; CO-US-412-6203 (Other Grant/Funding Number: Gilead Sciences)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes