NCT07215325 · Emory University
Got Doxy- 'Flipping the Script' on STI PEP
What this study is about
This study is being done to test the effects of doxycycline on inflammation and the bacteria in the body in people with HIV and in people on HIV pre-exposure prophylaxis. This drug is approved by the Food and Drug Administration (FDA) for the treatment of bacterial infections.
View original scientific description
This study is being done to test the effects of doxycycline on inflammation and the bacteria in the body in people with HIV and in people on HIV pre-exposure prophylaxis. This drug is approved by the Food and Drug Administration (FDA) for the treatment of bacterial infections. The study team will investigate whether the drug has additional effects on inflammation or on the bacteria that live in the body.
Interventions
DRUG
Doxycycline monohydrate 200 mg
Doxycycline monohydrate 200 mg (two 100 mg tablets) is used to treat or prevent infections that are strongly suspected to be caused by bacteria. Doxycycline monohydrate is an antimicrobial drug indicated for the treatment of bacterial infections, including sexually transmitted diseases. Centers for Disease Control and Prevention (CDC) recommends its use as post-exposure prophylaxis (PEP). Blood and rectal mucosal samples will be collected before doxycycline is initiated. Participants will be instructed to take 200 mg of doxycycline by mouth every Monday, Wednesday, and Friday. Additional doses of doxycycline will be permitted on other days if sex without a condom occurs per CDC guidance. After 12 weeks of at least three-weekly doxycycline, blood and rectal mucosal samples will be collected for immunologic and microbiome/resistome assays.
OTHER
Observation
Standard of care. Blood and rectal mucosal samples.
Primary outcome measures
Composite inflammation score
Time frame: Baseline and 12 weeks after the start of doxycycline administration
A composite inflammation score in the blood and rectal secretions before and after doxy-PEP will be calculated for each participant: +1 point for each proinflammatory cytokine (IP-10, IL-1β, tumor necrosis factor (TNF-α), Monocyte chemoattractant protein-1 (MCP-1), IL-17A, IL-6, interferon (IFN-γ), IL-12p70, IL-8) that was in the top quartile concentration and -1 point for each anti-inflammatory cytokine (IL-4, IL-10), T-cell growth factor (TGF-β1) that was in the top quartile concentration for a maximum score of 9 and minimum score of -3.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Age \>18 years
- Assigned male sex at birth
- Good general health as assessed by a clinician at the screening study visit
- For people with HIV, on suppressive antiretroviral therapy for at least 6 months with the most recent viral load documented \<50 copies/ml and the most recent cluster of differentiation 4 (CD4)\>300cells/ul
- For people without HIV, taking oral daily, oral on-demand, or injectable pre-exposure prophylaxis for at least 3 months at the time of enrollment, with plans to continue for the duration of the study
- Additional criteria apply
Exclusion criteria
- Severe/uncontrolled comorbidities that could influence immune outcomes (e.g., diabetes, hypertension, co-infections), as assessed by the investigator.
- History of inflammatory bowel disease (IBD) or other inflammatory, infiltrative, infectious, or vascular condition involving the lower GI tract that, in the judgment of the investigators, may be worsened by study procedures or may significantly distort the anatomy of the distal large bowel.
- Known allergy to doxycycline
- Use of any antibiotics within 3 months before screening
- Significant lab abnormalities at baseline visit for rectal biopsies,
- Continued need for the following medications during the study:
- Warfarin, heparin (LMW or unfractionated), platelet aggregation inhibitors, or fibrinolytic agents
- Any form of rectally administered agent besides products (lubricants or douching) used for sexual intercourse
- NSAIDS within 72 hours of rectal sampling procedures
- Continued need for, or use during the 90 days before enrollment, of the following medications:
- Systemic immunomodulatory agents
- Supraphysiologic doses of corticosteroids, except for short-course corticosteroids \<7 days duration at the discretion of the investigator. (Gender affirming hormone therapy is not exclusionary.)
- Use of experimental medications, vaccines, or biologicals in the 12 months before enrollment
Where
- Atlanta, Georgia
Collaborators
National Institute of Allergy and Infectious Diseases (NIAID)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 30, 2026 · Source of record for eligibility and locations