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

• Status: Not yet recruiting
• Trial end date: 2021-12-31
• Target enrollment: 0
• Participant gender: Male

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.

• Phase: Phase 4
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: British Columbia Centre for Disease Control
• Treatments: Doxycycline

Criteria

The inclusion criteria for this study are as follows:

1. Males, ≥ 18 years of age at baseline;

2. Self-reported MSM status;

3. Self-report condomless anal sex with a man within the last 6 months;

4. Laboratory documentation of HIV-1 infection;

5. 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);

6. Able to provide informed consent.

The exclusion criteria for this study are as follows:

1. Known allergy or intolerance to doxycycline or tetracyclines;

2. A known diagnosis of myasthenia gravis;

3. Use of medications which could lower doxycycline levels, including barbiturates, phenytoin and carbamazepine;

4. Individuals using isotretinoin;

5. Any individual capable of getting pregnant.