A Phase 4 interventional study of Doxycycline and Standard of Care (SOC) in Chlamydia Females, Gonorrhea Female and Syphilis Female, sponsored by Tulane University. Not yet recruiting. Open to female participants aged 18 Years to 35 Years. Per ClinicalTrials.gov, last updated 2026-07-15.
Sponsored by Tulane University · Phase 4, Interventional, and Treatment
The bacterial sexually transmitted infections (STIs) chlamydia, gonorrhea, and syphilis cause multiple adverse outcomes in women, and prevention strategies are critically needed. This project will determine the efficacy of doxycycline post-exposure prophylaxis (doxy PEP) to prevent STIs among women through a phase IV, open-label, randomized controlled trial.
The bacterial sexually transmitted infections (STIs) chlamydia (CT), gonorrhea, and syphilis cause multiple adverse outcomes in women, and rates of these infections have increased dramatically over the past two decades. Prevention of these infections is now possible with the use of doxycycline post-exposure prophylaxis (doxy PEP), which has demonstrated efficacy in multiple studies conducted among men from high prevalence groups. However, only one trial of the use of doxy PEP (dPEP Kenya) has been conducted among women, and unfortunately this study had a null result. Our proposed project seeks to evaluate doxy PEP efficacy among women in the United States through an open-label, randomized controlled trial (RCT) conducted in three jurisdictions (New Orleans, LA; Birmingham, AL; Chicago, IL) with high STI prevalence. Close adherence monitoring is critical given that the dPEP Kenya study's null result was likely related to poor medication adherence; thus, this trial will monitor and reinforce doxycycline adherence throughout the study using a novel PCheck app developed by our team, test urines for doxycycline levels on all participants, and hair on a nested cohort. The study's aim to conduct an RCT in 519 sexually active, non-pregnant women aged 18-35, randomizing 2:1 to better evaluate adverse events related to doxy PEP, powering the study on CT as the most commonly anticipated STI; sensitivity analyses will compare CT rates based on adherence measured by doxycycline levels in urine and by self-reported pill-taking. To execute these aims, we have assembled a multidisciplinary team with extensive expertise in the conduct of clinical trials, bioinformatics, biostatistics, infectious diseases epidemiology, STI prevention, the vaginal microbiome, behavioral health interventions, and qualitative science. MPIs Clement, Kissinger, and Muzny collectively have decades of collaborative experience enrolling priority populations in large clinical trials aimed to improve sexual health outcomes. Ultimately, this trial has the potential to have substantial public health impact, leading to a novel bacterial STI prevention intervention to reduce the undue burden of incident bacterial STIs among women.
167 studies on the registry are indexed under Gonorrhea; 31 are open to participants now.
This study's planned enrollment of 519 is above the median of 400 across 125 interventional studies indexed under Gonorrhea.
Browse Gonorrhea studies →Tulane University is the lead sponsor of 96 studies on the registry; 23 are open to participants now.
Of its 9 completed or terminated interventional studies of FDA-regulated products, 5 (56%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Reporting condomless vaginal sex with men AND least one of the following:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CD4 count
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
200 mg oral doxy PEP (N=346)
Drug: Doxycycline
Standard of care (i.e. no doxy PEP, N=173)
Other: Standard of Care (SOC)
Enrolled participants will be randomized 2:1 to receive 200 mg of doxy PEP taken within 24 hours of condomless sex versus standard of care. Only one trial of the use of doxy PEP (dPEP Kenya) has been conducted among women, and unfortunately this study had a null result.
Also known as: Doxy PEP
Enrolled participants will be randomized 2:1 to receive 200 mg of doxy PEP taken within 24 hours of condomless sex versus standard of care. Only one trial of the use of doxy PEP (dPEP Kenya) has been conducted among women, and unfortunately this study had a null result.
chlamydia incidence
The primary outcome will be the number of CT infections over person-time (incidence rate).
Time frame: Participants will be evaluated at baseline and quarterly for 48 weeks with STI testing at each visit.
No study locations are listed for this record.
Plan to share: Yes — STI lab tests results, surveys results from baseline and quarterly visits, app data, doxycycline drug levels by urinalysis, doxycycline hair levels
Access criteria: Data will be shared in dedicated data repositories. The selected repositories will provide a persistent unique identifier for the datasets such as a Digital Object Identifier (DOI) or accession number. The unique identifiers will be included in associated publications. Dataset submission will be populated with keywords to maximize findability of the datasets. Access to the shared data will be free and unrestricted. Persons who wish to access raw data will need to send a written request to the MPIs (Drs. Kissinger, Muzny, and Clement), providing them with an explanation of the reason for the request. This request will be reviewed by the MPIs and, if deemed appropriate, submitted to the IRB of record for approval.
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Doxycycline
Tulane University