Daily doxycycline treatment for early syphilis

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This clinical trial aims to evaluate the effectiveness of a daily dose of 200mg doxycycline taken for 14 days in treating early stage syphilis. Unlike the traditional twice-daily regimen, this study investigates the potential of a single daily dose based on lab data suggesting it may be effective. Participants will undergo regular testing and surveys to assess clinical improvement and blood test results over a six-month period. The study will include a small cohort of 15 participants diagnosed with early syphilis.

Why it matters

Who can join: the full rules

Inclusion Criteria:

Clinical diagnosis of syphilis (primary or secondary) or laboratory-confirmed early latent syphilis. Specifically: This will include persons meeting any one of the following criteria:

1. Clinical diagnosis of primary syphilis (based on the presence of a chancre) and either a positive qualitative RPR in the absence of a prior positive RPR on their most recent serological test for syphilis or a positive darkfield microscope exam of material taken from a chancre, OR
2. Clinical diagnosis of secondary syphilis with a positive qualitative RPR in the absence of a prior positive RPR on their most recent serological test for syphilis, OR
3. A laboratory-confirmed diagnosis of early latent syphilis within one month (i.e. \<31 days prior).

Exclusion Criteria:

1. age under 18
2. persons with evidence of neurosyphilis (including ocular and otic syphilis) or tertiary syphilis
3. persons who are unable to give informed consent
4. persons deemed by the study investigators to be unable to complete study follow-up visits
5. persons with an allergy to doxycycline
6. pregnant persons
7. persons with HIV who report that they are off antiretroviral medication or that they are not virologically suppressed
8. persons with other known forms of immunosuppression (e.g., persons taking systemic immunosuppressant drugs, persons with primary immunodeficiencies)
9. persons taking medications that would interact with doxycycline
10. persons whose initial RPR is lower than 1:4
11. persons currently prescribed doxy PEP
12. breastfeeding persons

Persons whose initial laboratory serological tests do not confirm the diagnosis of syphilis with an RPR of 1:4 or higher will be informed that they do not meet study criteria and advised to discontinue doxycycline 200mg once daily. Their subsequent treatment will be based on the judgement of non-research, clinical staff in the clinic and reflect shared decision making between clinical providers and their patient.

Where it's running

• Public Health Sexual Health Clinic
  Seattle, Washington, United States Recruiting

Study contacts

• Principal investigator: Travis Hunt, MD — University of Washington
• Study coordinator: Travis Hunt, MD
• Email: thunt91@uw.edu
• Phone: 206-685-4456

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.