CompletedPhase 4

Oral Doxycycline for the Prevention of Syphilis in Men Who Have Sex with Men (DaDHS)

Canada52 participantsStarted 2019-08-15

Plain-language summary

Syphilis is a sexually transmitted infection (STI) disproportionately affecting gay, bisexual and other men who have sex with men (gbMSM), with the potential for significant sequelae - particularly in those who are Human Immunodeficiency Virus (HIV)-positive. Rising rates of this STI have prompted a search for novel prevention solutions. A recent pilot study of daily doxycycline prophylaxis demonstrated promise as a novel STI prevention tool. This innovative approach to STI prevention has solid clinical precedent, both from the HIV pre-exposure prophylaxis (PrEP) literature, as well as doxycycline's use as prophylaxis for other infections. The overarching goal of this project is to determine whether the daily use of doxycycline is an efficacious and acceptable intervention for syphilis prevention in high-risk, HIV-positive gbMSM.

Who can participate

Age range

18 Years

Sex

MALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Males, ≥ 18 years of age at baseline;
. Self-reported MSM status;
. Self-report condomless anal sex with a man within the last 6 months;
. Laboratory documentation of HIV-1 infection;
. Prior diagnosis of early/infectious syphilis (i.e. primary, secondary or early latent) within preceding 36 months (defined on the basis of a new positive serum rapid plasma reagin (RPR) test, or ≥2-dilution rise in titre if previous syphilis, or positive darkfield microscopy result or T. pallidum direct fluorescent antibody test or PCR from a primary lesion);
. Able to provide informed consent.

Exclusion criteria

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

To assess the proportion of participants who are eligible and consent to participate amongst those approached.

Timeframe: 15 months

To assess the proportion of participants reporting > 95% adherence to study drug, according to self-report and pill counts.

Timeframe: 15 months

To assess the proportion of individuals with therapeutic doxycycline drug level (defined at ≥ 1000 ng/mL) at each study time point.

Timeframe: 15 months

To assess the proportion of individuals reporting grade 3 or 4 adverse events in each study arm.

Timeframe: 15 months

Proportion of individuals with adverse event-related study drug discontinuation in each study arm.

Timeframe: 15 months

Trial details

NCT IDNCT02864550

SponsorBritish Columbia Centre for Disease Control

Sponsor typeOTHER_GOV

Study typeINTERVENTIONAL

Primary completion2024-04-05

View on ClinicalTrials.gov More Syphilis trials

Plain-language summary

Who can participate

Age range

18 Years

Sex

MALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Males, ≥ 18 years of age at baseline;
. Self-reported MSM status;
. Self-report condomless anal sex with a man within the last 6 months;
. Laboratory documentation of HIV-1 infection;
. Prior diagnosis of early/infectious syphilis (i.e. primary, secondary or early latent) within preceding 36 months (defined on the basis of a new positive serum rapid plasma reagin (RPR) test, or ≥2-dilution rise in titre if previous syphilis, or positive darkfield microscopy result or T. pallidum direct fluorescent antibody test or PCR from a primary lesion);
. Able to provide informed consent.

Exclusion criteria

What they're measuring

To assess the proportion of participants who are eligible and consent to participate amongst those approached.

Timeframe: 15 months

To assess the proportion of participants reporting > 95% adherence to study drug, according to self-report and pill counts.

Timeframe: 15 months

To assess the proportion of individuals with therapeutic doxycycline drug level (defined at ≥ 1000 ng/mL) at each study time point.

Timeframe: 15 months

To assess the proportion of individuals reporting grade 3 or 4 adverse events in each study arm.

Timeframe: 15 months

Proportion of individuals with adverse event-related study drug discontinuation in each study arm.

Timeframe: 15 months