Got Doxy- 'Flipping the Script' on STI PEP

Emory University

Status and phase: Enrolling; Phase 4

Conditions: Sexually Transmitted Infections (STI)

Treatments: Drug: Doxycycline monohydrate 200 mg; Other: Observation

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT07215325

2025P009920 (Other Identifier)

STUDY00009355

1R01AI192319-01 (U.S. NIH Grant/Contract)

Details and patient eligibility

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.

The study team will investigate whether the drug has additional effects on inflammation or on the bacteria that live in the body.

Full description

This project aims to determine the potential anti-inflammatory and microbiome effects of doxycycline when used as post-exposure prophylaxis (Doxy PEP) for sexually transmitted infections (STIs).

This study is important in the field of research because it allows the investigators to define the systemic and gut anti-inflammatory, microbiome, and resistome effects of doxycycline when used as post-exposure prophylaxis (Doxy PEP) for sexually transmitted infections. The study population that this study seeks to enroll consists of healthy people assigned male at birth, with and without HIV, who are willing to undergo study procedures.

Study procedures will include the collection of medical history, as well as biological specimen sampling, such as blood and rectal tissue biopsies.

The duration of this clinical trial for study participants will be approximately 12 weeks. This will include five in-person visits lasting about 45 minutes to 1 hour (including two biopsy visits).

This study will utilize data specimen banking for future research.

Enrollment: 200 estimated patients

Sex: Male

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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200 participants in 2 patient groups

Doxycycline 200mg

Experimental group

Description:

Males with HIV infection on antiretroviral therapy or without HIV infection on HIV pre-exposure prophylaxis who are not taking doxy-PEP will be enrolled and randomized to take 12 weeks of doxycycline 200 mg by mouth three times weekly. Blood and rectal mucosal samples will be collected before the initiation of doxycycline.

Treatment:

Drug: Doxycycline monohydrate 200 mg

Observation with biological sampling

Active Comparator group

Description:

Males with HIV infection on antiretroviral therapy or without HIV infection on HIV pre-exposure prophylaxis who are not taking doxy-PEP will receive standard of care and will undergo biological sampling.

Treatment:

Other: Observation