A Randomized Controlled Trial of Doxycycline Post Exposure Prophylaxis to Prevent Incident Bacterial STIs Among Women in the United States

NCT07704957 | Not Yet Recruiting Phase 4 DMC FDA Drug

• 1 other identifier: R01AI196614
• Study Type: interventional
• Target: 519
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Chlamydia Females; Gonorrhea Female; Syphilis Female; Adherence; Prophylaxis; Prevention

Outcome Measures

Primary Outcomes (1)

• chlamydia incidence

  The primary outcome will be the number of CT infections over person-time (incidence rate).

  Participants will be evaluated at baseline and quarterly for 48 weeks with STI testing at each visit.

Study Arms (2)

Intervention

EXPERIMENTAL

200 mg oral doxy PEP (N=346)

Drug: Doxycycline

Control

ACTIVE COMPARATOR

Standard of care (i.e. no doxy PEP, N=173)

Other: Standard of Care (SOC)

Interventions

Doxycycline DRUG

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

Intervention

Standard of Care (SOC) OTHER

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.

Control

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Female
• Aged 18-35
• Reporting condomless vaginal sex with men AND least one of the following:
• diagnosis of CT, gonorrhea, syphilis, or trichomonas in the past year
• reporting 2 or more sexual partners in the past 6 months
• Plan to continue to be sexually active over the next year
• Have smartphone and be willing to engage with an app
• If HIV+: Viral load\<200 copies/ml and CD4 count \>200 cells/mm3

You may not qualify if:

• Pregnant, nursing, or intending to become pregnant
• Reported allergy to tetracyclines
• Liver disease or end-stage renal disease
• Non-English Speaking
• Taking concomitant medications which may impact doxycycline metabolism (e.g., systemic retinoids, antacids, barbiturates, carbamazepine, phenytoin, iron, warfarin, rifampin)
• Not willing to take doxy PEP or comply with study procedures
• Unable to provide informed consent

Sponsors & Collaborators

• Tulane University: lead
• National Institute of Allergy and Infectious Diseases (NIAID): collaborator
• University of Alabama at Birmingham: collaborator
• Louisiana State University Health Sciences Center in New Orleans: collaborator

MeSH Terms

Interventions

Doxycycline; Standard of Care

Intervention Hierarchy (Ancestors)

Tetracyclines; Naphthacenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Organic Chemicals; Polycyclic Compounds; Quality Indicators, Health Care; Quality of Health Care; Health Services Administration; Health Care Quality, Access, and Evaluation

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 10, 2026
• First Posted: July 15, 2026
• Study Start (Estimated): January 1, 2027
• Primary Completion (Estimated): February 28, 2031
• Study Completion (Estimated): April 1, 2032
• Last Updated: July 15, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share
• 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.