NCT07215325

Got Doxy- 'Flipping the Script' on STI PEP

The Effects of Doxycycline on Inflammation and the Microbiome: 'Flipping the Script' on STI PEP

• Status: Recruiting
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 200 (estimated)
• Sponsor: Emory University · Academic / Other
• Sex: Male
• Age: 18 Years
• Healthy volunteers: Accepted

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)

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2025-10-22
• Primary completion: 2028-09-01
• Completion: 2028-09-01
• First posted: 2025-10-10
• Last updated: 2025-12-12

Locations

2 sites across 1 country: United States

Regulatory

• FDA-regulated drug study