Got Doxy- 'Flipping the Script' on STI PEP

NCT ID: NCT07215325

Last Updated: 2025-12-12

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: PHASE4
• Total Enrollment: 200 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-10-22
• Study Completion Date: 2028-09-30

Brief Summary

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.

Detailed 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.

Conditions

Sexually Transmitted Infections (STI)

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Doxycycline 200mg

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.

Group Type: EXPERIMENTAL

Doxycycline monohydrate 200 mg

Intervention Type: DRUG

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.

Observation with biological sampling

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.

Group Type: ACTIVE_COMPARATOR

Observation

Intervention Type: OTHER

Standard of care. Blood and rectal mucosal samples.

Interventions

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.

Intervention Type: DRUG

Observation

Standard of care. Blood and rectal mucosal samples.

Intervention Type: OTHER

Other Intervention Names

Doxycycline; Standard of Care

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute of Allergy and Infectious Diseases (NIAID)

NIH

Sponsor Role: collaborator

Emory University

OTHER

Sponsor Role: lead

Responsible Party

Colleen Kelley

Professor of Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Colleen Kelley, MD, MPH

Role: PRINCIPAL_INVESTIGATOR

Emory University

Locations

Grady Health System (non-CRN)

Atlanta, Georgia, United States

Site Status: RECRUITING

Hope Clinic

Atlanta, Georgia, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Colleen Kelley, MD, MPH

Role: CONTACT

kelley@emory.edu

404-712-1823

Facility Contacts

Colleen Kelley, MD, MPH

Role: primary

colleen.kelley@emory.edu

404-712-1823

Colleen Kelley, MD, MPH

Role: primary

colleen.kelley@emory.edu

404-712-1823

Other Identifiers

1R01AI192319-01

Identifier Type: NIH

Identifier Source: secondary_id

View Link

2025P009920

Identifier Type: OTHER

Identifier Source: secondary_id

STUDY00009355

Identifier Type: -

Identifier Source: org_study_id