Impact of the Daily Doxycycline Pre-exposure Prophylaxis (PrEP) on the Incidence of Syphilis, Gonorrhoea and Chlamydia (Syphilaxis)

October 3, 2023 updated by: Kirby Institute

1. This study is a non-randomized observational cohort trial using before and after comparison to evaluate intervention 2. It would mimic the conditions that would occur outside a clinical trial. 2. After consent and enrolment, all procedures will be guided by the Australian STI Management Guidelines.

3. All enrolling participants will be offered daily doxycycline 100mg 4. All participants will be invited to complete a survey in every 3 months time for 12 months dated from participation.

5. All follow-up information will be collected through electronic data capture to allow accurate and timely analyses.

6. Data collection will be from (i) medical records (ii) online self-completed questionnaire

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

The last decade has seen increasing rates of bacterial STIs in Australia in gay and bisexual men in particular. Although STIs are easy to diagnose and treatment is effective, untreated STIs can cause significant health issues.

Previous research has shown that taking two100mg doxycycline tablets within 24 hours of sex as prophylaxis reduces syphilis and chlamydia significantly. Also a pilot trial conducted in the US suggested that using 100mg doxycycline as prophylaxis reduced the incidence of gonorrhoea, syphilis and chlamydia. Thus the question of whether taking doxycycline daily in high risk population would reduce the rate of STIs arose.

We set up this study as a non-randomized observational cohort trial using a before and after comparison to evaluate if taking 100mg doxycycline daily would help high risk gay and bisexual men to reduce the possibility of acquiring gonorrhoea, syphilis and chlamydia. Our primary objectives are to:assess acceptability of a daily dosing regimen for doxycycline prophylaxis, and measure the efficacy of 100mg daily doxycycline STI prophylaxis against reinfection with gonorrhoea, chlamydia and syphilis. Our secondary objectives are to: describe patterns of doxycycline use and medication adherence to the recommended schedule participants; evaluate change in behavioral among all study participants; evaluate resistance in the gut microbiota and in those colonized by S aureus at baseline and end of study, in a subset of consenting participants.

The study will be conducted in 3 sexual health centres. Eligible participants will undergo standard care in their trimonthly visit recommended by STI testing guideline, and complete informed consent and a baseline survey. They will be given daily dose of 100mg oral doxycycline for 3 months during the visit, and instruction of how to take the medicine. Questionnaires will be sent out to participants in every 3 months electronically and data will be collected and stored directly into the study survey database. Each participant will be follow-up for 12 months.

Study Type

Observational

Enrollment (Actual)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

    • New South Wales
      • Camperdown, New South Wales, Australia, 2050
        • Royal Prince Alfred Hospital Sexual Health Medicine
      • Syd, New South Wales, Australia, 2000
        • Sydney Sexual Health Centre
      • Sydney, New South Wales, Australia, 2010
        • Kirketon Road Centre
    • Victoria
      • Melbourne, Victoria, Australia, 3053
        • Melbourne Sexual Health Centre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Men who report male to male sex in the last 3 months and who have had at least two screening for syphilis, chlamydia and gonorrhoea in the last 12 months, and at least once incidence of syphilis in the last two years, are eligible for the study.

Description

Inclusion Criteria:

  • Male or transgender
  • Aged 18 years or over
  • Reports sex with men in last 3 months
  • At least two screenings for syphilis, gonorrhoea and chlamydia in the past 12 months
  • A diagnosis of syphilis within the last 12 months, OR a diagnosis of any 2 STIs within the last 12 months and syphilis within the last 24 months.
  • HIV +ve, OR HIV -ve and on PrEP for at least 6 months.

Exclusion Criteria:

  • Documented or self-reported hypersensitivity to doxycycline or antimicrobial agents from tetracycline family
  • A known diagnosis of myasthenia gravis
  • Factors or conditions that may compromise a participant's access to health services for follow-up (incarceration or planned relocation that would impact upon proximity to a trial site).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of STI (gonorrhoea, chlamydia and infectious syphilis) per 100 person years among study participants
Time Frame: 1 year after the last participant complete their last follow-up visit
measured using data collected by the ACCESS study
1 year after the last participant complete their last follow-up visit
Patterns of daily doxycycline use and adherence to the medication schedule
Time Frame: 1 year after the last participant complete their last follow-up visit
measured among participants consenting to the adherence and behavioural online survey
1 year after the last participant complete their last follow-up visit

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evidence of clinically significant antibiotic resistance in in a subset of participants
Time Frame: 1 year after the last participant who's recruited from the Melbourne site
including those who do contract STIs during the study and those who don't
1 year after the last participant who's recruited from the Melbourne site
Behavioural risk practices among study participants
Time Frame: 1 year after the last participant complete their last follow-up visit
in participants who consent to behavioral data collection online
1 year after the last participant complete their last follow-up visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Bridget Haire, PhD, Kirby Institute, UNSW

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 17, 2019

Primary Completion (Estimated)

July 17, 2024

Study Completion (Estimated)

December 17, 2024

Study Registration Dates

First Submitted

October 12, 2018

First Submitted That Met QC Criteria

October 12, 2018

First Posted (Actual)

October 17, 2018

Study Record Updates

Last Update Posted (Actual)

October 5, 2023

Last Update Submitted That Met QC Criteria

October 3, 2023

Last Verified

October 1, 2023

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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