The Women TDF-FTC Benchmark Study

Pharmacology of TDF-FTC Pre-exposure Prophylaxis in Kenyan Cisgender Women

The study seeks to define the expected blood levels of pre-exposure prophylaxis (PrEP) medications (tenofovir) for cisgender women taking directly observed oral PrEP therapy to understand the frequency of PrEP dosing associated with HIV protection in cisgender women. Cisgender women will be randomly assigned to receive varying frequencies of weekly PrEP doses and followed for up to 16 weeks. The study will also investigate how pregnancy affects the expected blood levels to help define optimal dosing of PrEP for HIV prevention during pregnancy.

Study Overview

• Status: Completed
• Conditions: HIV Infections
• Intervention / Treatment: Drug: co-formulated 300 mg TDF/ 200mg FTC

Detailed Description

This is an open-label, randomized, three-arm, directly observed therapy (DOT) 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 Disoproxil Fumarate/Emtricitabine (TDF/FTC) oral PrEP to help differentiate poor and moderate from perfect dosing. An additional cohort of pregnant women at high risk of HIV acquisition will be recruited and will receive daily dosing of TDF/FTC oral PrEP to evaluate the impact of pregnancy on blood and cellular drug levels. Study participants will receive directly observed oral PrEP for eight weeks, and will be followed for an additional eight weeks after their final PrEP dose. Drug concentrations in blood, vaginal fluid, and tissue will be measured during the study. The primary objectives of the study are:

1. 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 TDF/FTC at 2, 4, and 7 doses per week, representing poor, moderate, and perfect adherence, respectively.
2. To establish a model to predict adherence rate to TDF/FTC by level of TFV-DP observed in DBS for cisgender women. HIV-uninfected non-pregnant cisgender women will be randomly assigned to 1 of 3 dosing frequencies of directly observed therapyt of TDF/FTC oral PrEP: 2, 4, or 7 doses/week to differentiate poor and moderate from perfect adherence.

The study is the first to define TDF/FTC PrEP adherence-blood concentration thresholds for African cisgender women, a priority population for HIV prevention. The findings will guide accurate interpretation of adherence and success of PrEP programs in cisgender women. This data will also help guide decisions on optimal PrEP dosing for pregnant cisgender women at risk of acquiring HIV in Africa.

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Phase 2

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 would interfere with study participation
• Lack of severe anemia
• Willing to use DOT and come to clinic frequently for DOT PrEP for at least 8 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 8 weeks.
• Resides or works in catchment area with high speed internet coverage to permit video streaming

Specific for non-pregnant cisgender women cohort

• Not pregnant or breast feeding
• 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.

Specific for pregnant cisgender women only

• At screening, evidence of a viable pregnancy with gestational age of 13-26 weeks after the date of conception with sonographic confirmation. If adequate sonographic results are not available from medical records at screening, an ultrasound must be performed in the interim so that the result is available at study entry.
• At elevated risk for acquiring HIV according to Kenya guideline for PrEP. This is to ensure an ethical approach for provision of PrEP in pregnancy (i.e., only exposing PrEP to those who want and might benefit from it). 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, no or inconsistent condom use
• At study entry, willing to use PrEP during pregnancy for HIV prevention

Exclusion Criteria:

• For all cisgender women
• 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®, 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

Specific for non-pregnant cisgender women cohort

• 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.

Specific for pregnant cisgender women cohort

• Mother has a known history of any of the following, as determined by the site investigator or designee based on maternal report and available medical records:
• Sickle cell anemia (excluding sickle cell trait), chronic bleeding, blood transfusion within the past 120 days (excluding for chronic illness) or other blood dyscrasias
• Fetus has a known or suspected major congenital anomaly, from chart review of prior data, defined ultrasound.
• Complications in prior pregnancies that would be considered exclusionary

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

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Perfect Adherence; Cisgender women will receive a single tablet of co-formulated 300 mg TDF/ 200mg FTC once daily (7 doses per week).	Drug: co-formulated 300 mg TDF/ 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 300 mg TDF/ 200mg FTC; Other Names: Truvada
Experimental: Moderate Adherence; Cisgender women will receive a single tablet of co-formulated 300 mg TDF/ 200mg FTC tablet 4 times per week (Monday, Tuesday, Thursday, Friday)	Drug: co-formulated 300 mg TDF/ 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 300 mg TDF/ 200mg FTC; Other Names: Truvada
Experimental: Poor Adherence; Cisgender women will receive a single tablet of co-formulated 300 mg TDF/ 200mg FTC tablet twice per week(Monday and Tuesday)	Drug: co-formulated 300 mg TDF/ 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 300 mg TDF/ 200mg FTC; Other Names: Truvada
Experimental: Pregnant; Pregnant cisgender women will receive a single tablet of co-formulated 300 mg TDF/ 200mg FTC once daily (7 doses per week).	Drug: co-formulated 300 mg TDF/ 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 300 mg TDF/ 200mg FTC; Other Names: Truvada

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentrations of Tenofovir Disphosphate (TFV-DP) Measured at Eight Weeks in Dried Blood Spots (DBS)	TFV-DP concentrations observed in dried blood spots (DBS) after eight weeks of directly observed therapy with TDF/FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively. Emtricitabine triphosphate FTC-TP measures are not reported, as FTC-TP was not quantifiable in DBS samples from 100%, 81%, and 21% percent of participants receiving 2, 4, and 7 doses per week, respectively.	Assessed at 8 weeks
Concentrations of Tenofovir Disphosphate (TFV-DP) and Emtricitabine Triphosphate (FTC-TP) Measured at Steady-state in Peripheral Blood Mononuclear Cells (PBMCs).	Steady-state TFV-DP and FTC-TP concentrations observed in peripheral blood mononuclear cells (PBMCs) after eight weeks of directly observed therapy with TDF/FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively.	Assessed through 8 weeks
Fitted Steady-state TFV-DP Concentrations in Dried Blood Spots (DBS)	Fitted steady-state TFV-DP concentrations after eight weeks of directly observed therapy with TDF/FTC oral PrEP, in women randomized to receive 2, 4, or 7 doses per week, representing poor, moderate, or perfect adherence, respectively.	Assessed through 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency of Grade 2 or higher adverse events in participants	Based on signs, symptoms, labs, and diagnoses	Assessed through 8 weeks of DOT TDF/FTC PrEP
Frequency of infant death among infants of women in the pregnant cohort	Based on safety-related data recorded on case report forms and complete expedited adverse event (EAE) reporting by site investigators	Assessed through 12 months after delivery
Frequency of infant Grade 2 or higher adverse events among infants of women in the pregnant cohort	Assessed according to the Division of AIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table), Corrected Version 2.1, dated July 2017	Assessed through 12 months after delivery

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: University of Colorado, Denver; National Institute of Allergy and Infectious Diseases (NIAID); 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

Publications and helpful links

General Publications

• Mugwanya KK, Saina M, Mugo NR, MaWhinney S, Morrow M, Schaafsma TT, Donnell D, Glidden DV, Ngure K, Brown CE, Rechkina EA, Chohan BH, Wu L, Hill E, Koome E, Akelo N, Mbaire S, Morrison SA, Kibatha M, Njeru I, Muriithi M, Coppinger C, Bushman L, Baeten JM, Anderson PL; Women Benchmark Study Team. Adherence thresholds for emtricitabine-tenofovir disoproxil fumarate preexposure prophylaxis against HIV acquisition in cisgender women: A randomized directly observed dosing study. PLoS Med. 2025 Sep 9;22(9):e1004732. doi: 10.1371/journal.pmed.1004732. eCollection 2025 Sep.
• Wu L, Saina M, Brown C, Chege D, Donnell D, Glidden DV, Ngure K, Mugo NR, Akelo N, Schaafsma T, Anderson PL, Mugwanya KK. Establishing adherence-concentration-efficacy thresholds of TDF-FTC pre-exposure prophylaxis for HIV prevention in African women: a protocol for the Women TDF-FTC Benchmark Study. Front Reprod Health. 2024 May 27;6:1325257. doi: 10.3389/frph.2024.1325257. eCollection 2024.

Study record dates

Study Major Dates

• Study Start (Actual): April 25, 2022
• Primary Completion (Actual): October 1, 2024
• Study Completion (Actual): October 1, 2024

Study Registration Dates

• First Submitted: September 16, 2021
• First Submitted That Met QC Criteria: September 16, 2021
• First Posted (Actual): September 27, 2021

Study Record Updates

• Last Update Posted (Actual): June 15, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: HIV; Kenya; Pre-exposure Prophylaxis
• 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; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Pharmaceutical Preparations; Nucleic Acids, Nucleotides, and Nucleosides; Purines; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Organophosphorus Compounds; Nucleosides; Deoxyribonucleosides; Organophosphonates; Adenine; Drug Combinations; Tenofovir; Emtricitabine; Emtricitabine, Tenofovir Disoproxil Fumarate Drug Combination; Racivir
• Other Study ID Numbers: STUDY00011136; R01AI155086 (U.S. NIH Grant/Contract)

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