NCT06545656

Daily Doxycycline to Inform Sexually Transmitted Infection Prophylaxis Regimens

Daily Doxy: Study of Persons Receiving Daily Doxycycline to Inform Sexually Transmitted Infection Prophylaxis Regimens

• Status: Completed
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 23 (actual)
• Sponsor: Emory University · Academic / Other
• Sex: All
• Age: 18 Years – 59 Years
• Healthy volunteers: Accepted

Summary

The goal of this project is to collect data regarding the concentrations of doxycycline in mucosal tissues after daily dosing for 7 days in people assigned male sex at birth (AMAB) and assigned female sex at birth (AFAB) to inform future studies of doxycycline to protect against bacterial sexually transmitted infections (STIs).

Detailed description

Recent studies have demonstrated the potential utility of single-dose oral doxycycline postexposure prophylaxis (Doxy-PEP) against bacterial sexually transmitted infections (STIs). Additional dosing strategies are being explored that would also provide protection from bacterial STIs. However, the pharmacokinetics of daily doxycycline and specifically the effect of this dosing on effective drug levels in mucosal tissues is underexplored. A previous pilot study conducted by the Division of human immunodeficiency virus (HIV) Prevention (DHP) Laboratory Branch at the Centers for Disease Control and Prevention (CDC) examined the ability of a single 100mg oral dose of doxycycline to penetrate the vaginal and rectal mucosa. However, data regarding daily doxycycline doses and accumulation of doxycycline with multiple doses are lacking. The purpose of this project is to collect data regarding the ability of daily oral doxycycline taken for 7 days to concentrate in mucosal tissues in people assigned male sex at birth (AMAB) and assigned female sex at birth (AFAB). Results from this study will be compared to results of the previous pilot studies conducted by the DHP Laboratory Branch at CDC. Healthy people assigned male or female sex at birth will take the first dose of doxycycline during the enrollment visit (Hour -144/Day -6) then will take the next 5 doses at home, one per day for the next 5 days. After 6 consecutive days of dosing, study participants will have samples collected (Hour 0/Day 0) and then will take the final dose. Rectal and vaginal swab samples will be obtained 2 to 4 hours after the final dose of doxycycline. Rectal and vaginal biopsy tissue will be collected 24 hours after the last dose.

Conditions

• Sexually Transmitted Infection

Interventions

Type	Name	Description
DRUG	Doxycycline	Doxycycline (DOX) will be given orally at 100mg doses. Participants will take the study medication for 7 consecutive days.

Timeline

• Start date: 2024-09-13
• Primary completion: 2025-04-29
• Completion: 2025-04-29
• First posted: 2024-08-09
• Last updated: 2025-06-27

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study