Actively Recruiting

Phase 2
Age: 18Years +
All Genders
ID06683638

Daily Doxycycline for Early Syphilis Treatment Using 200mg Once Daily Dose for 14 Days

Led by University of Washington · Updated on 2025-06-25

15

Participants Needed

1

Research Sites

N/A

Total Duration

On this page

AI-Summary

What this Trial Is About

Researchers are evaluating whether taking doxycycline as a single daily dose of 200mg for 14 days is an effective treatment for early-stage syphilis. This differs from the usual treatment of doxycycline given twice daily at 100mg. The study aims to determine treatment success based on clinical improvement and blood test results within 6 months. The trial includes an open-label prospective cohort of 15 participants with early syphilis and compares outcomes to retrospective data of standard treatments. Participants diagnosed with early syphilis will take doxycycline 200mg once daily for 14 days. During this treatment period, they will collect oral and rectal swabs every other day, which will be sent by mail for testing. Participants will also complete two brief online surveys during these two weeks. Follow-up visits will occur at 3 and possibly 6 months for interviews and blood tests to assess treatment response. Throughout the study, participants will provide multiple samples and complete surveys to monitor the presence of syphilis bacteria and treatment effects. Blood tests will check for a fourfold decrease in syphilis activity at 3 and 6 months. Those showing improvement at 3 months may skip the 6-month visit. The main outcome measured is combined clinical and serological response after six months. The total study duration for participants is up to 6 months, with ongoing monitoring and comparison to standard treatment outcomes.

CONDITIONS

Brief Title

Daily Doxycycline for Early Syphillis

Who Can Participate

Age: 18Years +
All Genders

Eligibility Criteria

Eligible

You may qualify if you...

  • Clinical diagnosis of primary, secondary, or early latent syphilis
  • Positive qualitative RPR or laboratory confirmation within 31 days prior
  • RPR titer of 1:4 or greater
  • Age 18 years or older
  • Ability to provide informed consent and complete study visits
Not Eligible

You will not qualify if you...

  • Age under 18 years
  • Evidence of neurosyphilis or tertiary syphilis
  • Unable to give informed consent
  • Unable to complete study follow-up visits
  • Allergy to doxycycline
  • Pregnancy or breastfeeding
  • HIV positive persons not virologically suppressed or off antiretroviral medication
  • Other known immunosuppression or use of systemic immunosuppressants
  • Taking medications that interact with doxycycline
  • Currently prescribed doxycycline post-exposure prophylaxis (doxy PEP)

AI-Screening

AI-Powered Screening

Complete this quick 3-step screening to check your eligibility

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Your Study Journey

Screening

Duration - 2 to 4 weeks

Participants are screened for eligibility to participate in the trial.

1 visit (in-person)

Treatment

Duration - 14 days

Participants take doxycycline 200mg once daily for 14 days and perform oral and rectal swabs every other day during treatment, returning samples by mail. They also complete two brief online surveys during this period.

Swabs every other day for 14 days; 2 online surveys

Follow-up

Duration - Up to 6 months

Participants return for blood tests to monitor syphilis response at 3 months and, if needed, at 6 months following treatment. Participants with a positive response at 3 months may skip the 6-month visit.

1 visit at 3 months and possibly 1 visit at 6 months

Trial Site Locations

Total: 1 location

1

Public Health Sexual Health Clinic

Seattle, Washington, United States, 98104

Actively Recruiting

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Research Team

T

Travis Hunt, MD

M

Matthew Golden, MD, MPH

How is the study designed?

Study Type

INTERVENTIONAL

Masking

NONE

Allocation

NA

Model

SINGLE_GROUP

Primary Purpose

TREATMENT

Number of Arms

1

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