Clinical Trial

Superiority of On-demand PrEP Versus PEP on Using Doxycycline for Preventing STI in MSM

Active, Not Recruiting Phase 4
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Summary
The goal of this clinical trial is to compare the effectiveness of doxycycline taken for on-demand pre-exposure prophylaxis (DoxyODPrEP) and its post-exposure use (DoxyPEP) in preventing bacterial sexually transmitted infections (STI), including chlamydia, gonorrhoea, and syphilis among men who have sex with men (MSM). The main questions it aims to answer are: 1. Is DoxyODPrEP superior to DoxyPEP? 2. Are both regimens safe? 3. Does the MSM community accept the use of doxycycline to prevent bacterial STI? Participants will be asked to take doxycycline according to the study arm they are randomly assigned to, and attend regular clinical follow-ups during the 2-year observation period. Researchers will compare the bacterial STI incidences between the two groups to see if DoxyODPrEP is superior to DoxyPEP.
Protocol Amendment History 2 amendments
This ClinicalTrials.gov record has been amended 2 times since 2023-12-18; most recent amendment 2026-06-04.
Status change: Recruiting → Active, Not Recruiting 2026-06-04
Status change: Not Yet Recruiting → Recruiting 2025-04-02
Trial Details
NCT Number NCT06188442
Lead Sponsor Chinese University of Hong Kong
Conditions Sexually Transmitted Diseases, Bacterial, Syphilis, Gonorrhea, Chlamydia
Enrollment 300 participants
Start Date 2025-03-29
Primary Completion 2027-12-31 (estimated)
Study Completion 2028-12 (estimated)
Updated on ClinicalTrials.gov 2026-06-05