Flipping the script on STI prevention with doxycycline post-exposure (Doxy-PEP).

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This Phase 4 interventional study gives doxycycline monohydrate 200 mg as post-exposure prophylaxis to adults assigned male at birth, including people living with HIV on suppressive ART and people without HIV who are on PrEP. Participants attend five in-person visits over about 12 weeks, including blood draws and two rectal tissue biopsy visits to measure systemic and gut inflammation and microbiome/resistome changes. The study compares biological samples before and after Doxy-PEP use and includes specimen banking for future research. Safety monitoring and observational comparisons are included to detect adverse effects and potential antibiotic resistance signals.

Why it matters

Who can join: the full rules

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:

  1. Aspirin
  2. Warfarin, heparin (LMW or unfractionated), platelet aggregation inhibitors, or fibrinolytic agents
  3. Any form of rectally administered agent besides products (lubricants or douching) used for sexual intercourse
  4. NSAIDS within 72 hours of rectal sampling procedures
* Continued need for, or use during the 90 days before enrollment, of the following medications:

  1. Systemic immunomodulatory agents
  2. 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.)
  3. Use of experimental medications, vaccines, or biologicals in the 12 months before enrollment

Where it's running

• Grady Health System (non-CRN)
  Atlanta, Georgia, United States Recruiting
• Hope Clinic
  Atlanta, Georgia, United States Recruiting

Study contacts

• Principal investigator: Colleen Kelley, MD, MPH — Emory University
• Study coordinator: Colleen Kelley, MD, MPH
• Email: kelley@emory.edu
• Phone: 404-712-1823

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.