The goal of this clinical trial is to learn if three different dosing strategies of doxycycline (daily, weekly, and on-demand) works to prevent sexually transmitted infections (gonorrhea, chlamydia, and syphilis) among men who use methamphetamine and who have sex with other men. The main question it aims to answer is:
Does daily, weekly, and on-demand doxycycline dosing strategies lower the incidence of quarterly STIs (gonorrhea, chlamydia, and syphilis)?
Participants will:
Take doxycycline either on-demand (within 72 hours after sex), daily, or weekly doxycycline for one year Visit the clinic once every 3 months to complete questionnaires, undergo HIV/STI testing, and collect samples. Additional visits may be needed to receive STI treatment.
Complete text surveys once every month
This study will evaluate the acceptability, effectiveness, and adherence of alternative doxycycline dosing strategies to optimize STI prophylaxis in this high-risk population. We will accomplish this through the following independent, yet interrelated Aims: 1) Determine effectiveness of fixed-dose daily, fixed-dose weekly, and event-driven dosing of doxycycline for STI prophylaxis; 2) Assess acceptability and preferences for doxycycline as STI prophylaxis through either fixed dose (daily or weekly) or event-driven (post-exposure) dosing strategies through individual interviews; 3) Evaluate and compare adherence and tolerability of daily, weekly, and event-driven doxycycline dosing strategies. We will conduct an open-label, non-inferior, randomized control trial (RCT) comparing fixed-dose daily, fixed-dose weekly, and event-driven doxycycline dosing strategies on quarterly incidence of STIs among MSM who use MA. We will screen 900 individuals to recruit a cohort of 300 MSM who self-report MA use in conjunction with condomless anal intercourse in the past month. At the Enrollment visit, participants will receive HIV, syphilis, and gonorrhea/chlamydia (GC/CT) testing as well as complete demographic and behavioral questionnaires. Enrolled participants will be randomly assigned 1:1:1 to either fixed-dose daily doxycycline (100mg daily; n=100), fixed-dose weekly doxycycline (200mg weekly; n=100), or event-driven doxyPEP (200mg taken up to 72 hours after a potential STI exposure; n=100; standard of care). All participants will participate in Quarterly follow-up visits where they will be assessed for HIV, bacterial STIs (GC/CT and syphilis), adherence to doxycycline, sexual behaviors/practices, substance use, nasal Staph aureus colonization and doxycycline resistance over 12 months. The primary outcome for this study will be quarterly incidence of, GC, CT, and/or early syphilis (defined as newly positive rapid plasma reagin [RPR] or four-fold rise in RPR titers), by arm.