GonorrheaPhase 4DOSENCT07925255
Daily, Weekly, or Event-driven Doxycycline for STI Prevention Among Men Who Have Sex With Men (MSM) Engaging in Chemsex: The DOSE Non-inferiority Trial
A Phase 4 study testing On demand doxycycline hyclate 200mg, Daily doxycycline hyclate 100mg and Weekly doxycycline hyclate 100mg in people with Gonorrhea and Chlamydia, run by University of California, Los Angeles at 1 site in United States.
Trial summary
The goal of this clinical trial is to learn if three different dosing strategies of doxycycline (daily, weekly, and on-demand) works to prevent sexually transmitted infections (gonorrhea, chlamydia, and syphilis) among men who use methamphetamine and who have sex with other men. Read more about this study
- Who is it for?
- Ages 18 years and older, men only
- What is being tested?
- On demand doxycycline hyclate 200mg, Daily doxycycline hyclate 100mg and Weekly doxycycline hyclate 100mg
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 300 participants
- Where
- 1 siteUnited States
- Study dates
- Nov 2026to 30 Jun 2031
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Men only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Born male
- Age ≥ 18 years old
- Reports receiving an STI diagnosis (i.e., GC, CT, and/or syphilis) in the past 12 months
- Reports MA use in conjunction with CAI with a male partner in the 30 days prior to screening
- Not planning to relocate out of the study area in the 12-month follow-up period
- Willingness to engage in up to one year of repeated antibiotic exposure
- Willing and able to give written informed consent
Who cannot join
- Reported allergy to tetracyclines
- Current or anticipated use of a medication that interacts with doxycycline (prohibited medications listed below)
- Current or planned use of doxycycline for a prolonged period (> 2 weeks, with the exception of pre-enrollment doxyPEP)
- Prolonged antibiotic use (> 2 weeks, with the exception of pre-enrollment doxyPEP) in the 30 days prior to study enrollment
- Co-enrollment in any other concurrent study that may interfere with this study, such as an STI prevention trial, unless approved by the PI or designee
- Any other medical or psychiatric condition that, in the opinion of the PI or designee, may interfere with study participation or participant safety
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
UCLA Vine Street Clinic
Los Angeles, California, 90038
UCLA Vine Street Clinic, (323) 461-3106, uclavsc@mednet.ucla.edu
About this study
The goal of this clinical trial is to learn if three different dosing strategies of doxycycline (daily, weekly, and on-demand) works to prevent sexually transmitted infections (gonorrhea, chlamydia, and syphilis) among men who use methamphetamine and who have sex with other men. The main question it aims to answer is:
Does daily, weekly, and on-demand doxycycline dosing strategies lower the incidence of quarterly STIs (gonorrhea, chlamydia, and syphilis)?
Read more
Participants will:
Take doxycycline either on-demand (within 72 hours after sex), daily, or weekly doxycycline for one year Visit the clinic once every 3 months to complete questionnaires, undergo HIV/STI testing, and collect samples. Additional visits may be needed to receive STI treatment.
Complete text surveys once every month
Read the detailed description
This study will evaluate the acceptability, effectiveness, and adherence of alternative doxycycline dosing strategies to optimize STI prophylaxis in this high-risk population. We will accomplish this through the following independent, yet interrelated Aims: 1) Determine effectiveness of fixed-dose daily, fixed-dose weekly, and event-driven dosing of doxycycline for STI prophylaxis; 2) Assess acceptability and preferences for doxycycline as STI prophylaxis through either fixed dose (daily or weekly) or event-driven (post-exposure) dosing strategies through individual interviews; 3) Evaluate and compare adherence and tolerability of daily, weekly, and event-driven doxycycline dosing strategies. We will conduct an open-label, non-inferior, randomized control trial (RCT) comparing fixed-dose daily, fixed-dose weekly, and event-driven doxycycline dosing strategies on quarterly incidence of STIs among MSM who use MA. We will screen 900 individuals to recruit a cohort of 300 MSM who self-report MA use in conjunction with condomless anal intercourse in the past month. At the Enrollment visit, participants will receive HIV, syphilis, and gonorrhea/chlamydia (GC/CT) testing as well as complete demographic and behavioral questionnaires. Enrolled participants will be randomly assigned 1:1:1 to either fixed-dose daily doxycycline (100mg daily; n=100), fixed-dose weekly doxycycline (200mg weekly; n=100), or event-driven doxyPEP (200mg taken up to 72 hours after a potential STI exposure; n=100; standard of care). All participants will participate in Quarterly follow-up visits where they will be assessed for HIV, bacterial STIs (GC/CT and syphilis), adherence to doxycycline, sexual behaviors/practices, substance use, nasal Staph aureus colonization and doxycycline resistance over 12 months. The primary outcome for this study will be quarterly incidence of, GC, CT, and/or early syphilis (defined as newly positive rapid plasma reagin [RPR] or four-fold rise in RPR titers), by arm.
- Being tested
- On demand doxycycline hyclate 200mg, Daily doxycycline hyclate 100mg, Weekly doxycycline hyclate 100mg
- Keywords
- doxyPEP, STI
- Medical subject headings
- Gonorrhea, Chlamydia Infections, Syphilis, Sexually Transmitted Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
On demand doxycycline hyclate 200mgDrug
Participants randomized to receive on-demand doxycycline hyclate 200mg will be instructed to take doxycycline hyclate 200mg once as needed within 24 hours and up to 72 hours after sex (not to exceed 200mg in 24 hours)
Daily doxycycline hyclate 100mgDrug
Participants randomized to receive fixed dose daily doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once daily
Weekly doxycycline hyclate 100mgDrug
Participants randomized to receive weekly doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once weekly
| Study group | Role | What they receive |
|---|---|---|
| On-demand doxycycline | Experimental | Participants randomized to on-demand doxycycline will be instructed to take doxycycline hyclate 200mg once as needed within 24 and up to 72 hours after sex (not to exceed 200mg in 24 hours). Receives: Drug: On demand doxycycline hyclate 200mg |
| Weekly doxycycline | Experimental | Participants randomized to receive fixed dose weekly doxycycline hyclate 200mg will be instructed to take doxycycline hyclate 200mg once weekly, regardless of sexual exposure. Receives: Drug: Weekly doxycycline hyclate 100mg |
| Daily doxycycline | Experimental | Participants randomized to receive fixed dose daily doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once daily, regardless of sexual exposure. Receives: Drug: Daily doxycycline hyclate 100mg |
What is being measured
The primary outcome is the main question the study is designed to answer.
Quarterly incidence of chlamydia, gonorrhea, and/or early syphilis infection
Measured: Quarterly incidence of C. trachomatis, N. gonorrhoeae, and/or early syphilis infection by laboratory-based diagnosis (over 1 year time period)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Nov 2026
- Study startNov 2026 (estimated)
- Primary completion30 Jun 2030 (estimated)
- Study completion30 Jun 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for GonorrheaStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Responsible party
- Principal investigator, Cherie Blair, MD, PhD, University of California, Los Angeles
- Investigators
- Cherie Blair, MD, PhD, Principal investigator, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07925255
- Sponsor's protocol ID
- 26-1595
- Other IDs
- 1R01DA066392-01A1
- Acronym
- DOSE
- Status last verified
- Nov 2026
- First submitted
- 3 Nov 2026
- Last updated
- 9 Nov 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 9 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Daily, Weekly, or Event-driven Doxycycline for STI Prevention Among Men Who Have Sex With Men (MSM) Engaging in Chemsex: The DOSE Non-inferiority Trial
- ClinicalTrials.gov ID
- NCT07925255
- Acronym / sponsor ID
- DOSE / 26-1595
- Keywords
- doxyPEP, STI
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 300 participants (estimated)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- Nov 2026 (estimated)
- Primary completion
- 30 Jun 2030 (estimated)
- Study completion
- 30 Jun 2031 (estimated)
- First posted
- 9 Nov 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn if three different dosing strategies of doxycycline (daily, weekly, and on-demand) works to prevent sexually transmitted infections (gonorrhea, chlamydia, and syphilis) among men who use methamphetamine and who have sex with other men. The main question it aims to answer is:
Does daily, weekly, and on-demand doxycycline dosing strategies lower the incidence of quarterly STIs (gonorrhea, chlamydia, and syphilis)?
Participants will:
Take doxycycline either on-demand (within 72 hours after sex), daily, or weekly doxycycline for one year Visit the clinic once every 3 months to complete questionnaires, undergo HIV/STI testing, and collect samples. Additional visits may be needed to receive STI treatment.
Complete text surveys once every month
Detailed description
This study will evaluate the acceptability, effectiveness, and adherence of alternative doxycycline dosing strategies to optimize STI prophylaxis in this high-risk population. We will accomplish this through the following independent, yet interrelated Aims: 1) Determine effectiveness of fixed-dose daily, fixed-dose weekly, and event-driven dosing of doxycycline for STI prophylaxis; 2) Assess acceptability and preferences for doxycycline as STI prophylaxis through either fixed dose (daily or weekly) or event-driven (post-exposure) dosing strategies through individual interviews; 3) Evaluate and compare adherence and tolerability of daily, weekly, and event-driven doxycycline dosing strategies. We will conduct an open-label, non-inferior, randomized control trial (RCT) comparing fixed-dose daily, fixed-dose weekly, and event-driven doxycycline dosing strategies on quarterly incidence of STIs among MSM who use MA. We will screen 900 individuals to recruit a cohort of 300 MSM who self-report MA use in conjunction with condomless anal intercourse in the past month. At the Enrollment visit, participants will receive HIV, syphilis, and gonorrhea/chlamydia (GC/CT) testing as well as complete demographic and behavioral questionnaires. Enrolled participants will be randomly assigned 1:1:1 to either fixed-dose daily doxycycline (100mg daily; n=100), fixed-dose weekly doxycycline (200mg weekly; n=100), or event-driven doxyPEP (200mg taken up to 72 hours after a potential STI exposure; n=100; standard of care). All participants will participate in Quarterly follow-up visits where they will be assessed for HIV, bacterial STIs (GC/CT and syphilis), adherence to doxycycline, sexual behaviors/practices, substance use, nasal Staph aureus colonization and doxycycline resistance over 12 months. The primary outcome for this study will be quarterly incidence of, GC, CT, and/or early syphilis (defined as newly positive rapid plasma reagin [RPR] or four-fold rise in RPR titers), by arm.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| On-demand doxycycline | Experimental | Drug: On demand doxycycline hyclate 200mgParticipants randomized to on-demand doxycycline will be instructed to take doxycycline hyclate 200mg once as needed within 24 and up to 72 hours after sex (not to exceed 200mg in 24 hours). |
| Weekly doxycycline | Experimental | Drug: Weekly doxycycline hyclate 100mgParticipants randomized to receive fixed dose weekly doxycycline hyclate 200mg will be instructed to take doxycycline hyclate 200mg once weekly, regardless of sexual exposure. |
| Daily doxycycline | Experimental | Drug: Daily doxycycline hyclate 100mgParticipants randomized to receive fixed dose daily doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once daily, regardless of sexual exposure. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Born male
- Age ≥ 18 years old
- Reports receiving an STI diagnosis (i.e., GC, CT, and/or syphilis) in the past 12 months
- Reports MA use in conjunction with CAI with a male partner in the 30 days prior to screening
- Not planning to relocate out of the study area in the 12-month follow-up period
Key exclusion criteria (6 listed)
- Reported allergy to tetracyclines
- Current or anticipated use of a medication that interacts with doxycycline (prohibited medications listed below)
- Current or planned use of doxycycline for a prolonged period (> 2 weeks, with the exception of pre-enrollment doxyPEP)
- Prolonged antibiotic use (> 2 weeks, with the exception of pre-enrollment doxyPEP) in the 30 days prior to study enrollment
- Co-enrollment in any other concurrent study that may interfere with this study, such as an STI prevention trial, unless approved by the PI or designee
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| On demand doxycycline hyclate 200mgParticipants randomized to receive on-demand doxycycline hyclate 200mg will be instructed to take doxycycline hyclate 200mg once as needed within 24 hours and up to 72 hours after sex (not to exceed 200mg in 24 hours) | Drug | On-demand doxycycline |
| Daily doxycycline hyclate 100mgParticipants randomized to receive fixed dose daily doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once daily | Drug | Daily doxycycline |
| Weekly doxycycline hyclate 100mgParticipants randomized to receive weekly doxycycline hyclate 100mg will be instructed to take doxycycline hyclate 100mg once weekly | Drug | Weekly doxycycline |
Primary outcome
Quarterly incidence of chlamydia, gonorrhea, and/or early syphilis infection
Time frame: Quarterly incidence of C. trachomatis, N. gonorrhoeae, and/or early syphilis infection by laboratory-based diagnosis (over 1 year time period)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Nov 2026.
- Individual participant dataSharing planned: Yes
Related trials for Gonorrhea
Active, not recruitingPhase 4
Periodic Presumptive Treatment vs. doxyPEP for STI Control in Kenyan MSM
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Pilot HIV Self-Testing And Self-collected STI Testing Strategy for Sex Worker Empowerment Study
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Not yet recruitingPhase 3
A Clinical Study to Assess the Efficacy of Weekly Doxycycline Prophylaxis to Reduce Bacterial Sexually Transmitted Infections (STI) in Young African Women
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Doxycycline Prophylaxis for Prevention of Sexually Transmitted Infections
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Cherie Blair, MD, PhD principal investigator
University of California, Los Angeles
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing On demand doxycycline hyclate 200mg, Daily doxycycline hyclate 100mg and Weekly doxycycline hyclate 100mg in people with Gonorrhea and Chlamydia, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 9 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact UCLA Vine Street Clinic ((323) 461-3106, uclavsc@mednet.ucla.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Quarterly incidence of chlamydia, gonorrhea, and/or early syphilis infection (time frame: Quarterly incidence of C. trachomatis, N. gonorrhoeae, and/or early syphilis infection by laboratory-based diagnosis (over 1 year time period)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Nov 2026.