Sexually Transmitted Diseases, BacterialEarly Phase 1DOT-Doxy-PEPNCT06414408
Randomized Directly Observed Therapy Study to Interpret Clinical Trials of Doxy-PEP
A Early Phase 1 study testing Doxycycline Pill in people with Sexually Transmitted Diseases, Bacterial, run by University of California, San Francisco at 1 site in United States.
Trial summary
Rates of bacterial sexually transmitted infections (STIs) are rising globally, demanding innovative interventions beyond the scope of current efforts to prevent STIs. The United States Doxycycline Post-exposure Prophylaxis (DoxyPEP) Study has demonstrated the efficacy of doxycycline post-exposure prophylaxis (PEP)… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Sexually Transmitted Diseases, Bacterial
- What is being tested?
- Doxycycline Pill
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteUnited States
- Study dates
- 18 Oct 2024to 1 Dec 2028
- Phase
- Early Phase 1
- 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
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- not currently at risk of a sexually transmitted infection and willing to use other methods, such as condoms, for STI prevention;
- if diagnosed with an STI in the past two years and/or a partner was diagnosed with an STI in the past year, is willing to use condoms for STI prevention;
- willing to provide hair, blood, and urine samples;
- not currently enrolled in other STI prevention studies;
- able to speak English
- transgender women participants should be currently using estrogen gender affirming hormone therapy with blood estrogen levels demonstrating consistent use
Show all 10Show fewer
- transgender men participants should be currently using testosterone gender affirming hormone therapy with blood testosterone levels demonstrating consistent use
- able to provide a hair sample of ~50-100 strands of hair that are non-gray, not bleached, and at least 1cm in length
- willing to NOT shave hair or have a very short haircut or apply bleach for the duration of the study
- has suitable venous access for consecutive blood draws
Who cannot join
- any health condition that may interfere with participation or the ability to provide informed consent, including any debilitating or life-threatening conditions;
- pregnancy or plans to become pregnant;
- liver cirrhosis or fulminant liver disease;
- known hypersensitivity reaction to doxycycline.
- detectable doxycycline in hair at enrollment.
- unable to provide a hair sample of ~50-100 strands of hair that are non-gray, not bleached, and at least 1cm in length
- does not have suitable venous access for consecutive blood draws
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, 1 recruiting
- Recruiting
University of California, San Francisco/San Francisco General Hospital
San Francisco, California, 94110
Matthew A Spinelli, MD, MAS, matthew.spinelli@ucsf.edu
About this study
Rates of bacterial sexually transmitted infections (STIs) are rising globally, demanding innovative interventions beyond the scope of current efforts to prevent STIs. The United States Doxycycline Post-exposure Prophylaxis (DoxyPEP) Study has demonstrated the efficacy of doxycycline post-exposure prophylaxis (PEP) among men who have sex with men and transgender women; but puzzlingly, doxycycline PEP was found ineffective in cisgender women in the Kenyan doxycycline Post-Exposure Prophylaxis (dPEP) study, with preliminary data suggesting the low medication adherence may explain the null result. By study end, the investigators will have developed adherence measurement methods for doxycycline in hair, blood, and urine, and will use these techniques to help interpret the Kenyan dPEP study, and to examine the relative performance of these methods within the United States DoxyPEP trial, establishing adherence metrics for current and future rollout studies of doxycycline post-exposure prophylaxis
- Conditions
- Sexually Transmitted Diseases, Bacterial
- Being tested
- Doxycycline Pill
- Medical subject headings
- Sexually Transmitted Diseases, Bacterial
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Doxycycline PillDrug
200mg Dose
| Study group | Role | What they receive |
|---|---|---|
| Daily Dosing | Active comparator | Participants will be randomized to take once daily doxycycline 200mg for six weeks. Receives: Drug: Doxycycline Pill |
| Three-times Weekly Dosing | Active comparator | Participants will be randomized to take one doxycycline 200mg dose three times a week (Monday, Wednesday, and Friday) for six weeks. Receives: Drug: Doxycycline Pill |
| Weekly Dosing | Active comparator | Participants will be randomized to take one doxycycline 200mg dose once week. Receives: Drug: Doxycycline Pill |
| Every Other Week Dosing | Active comparator | Participants will be randomized to take one doxycycline 200mg dose every other week. Receives: Drug: Doxycycline Pill |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hair Doxycycline Concentration
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within hair samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
Measured: 4 weeks
Plasma Doxycycline Concentration
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within plasma samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
Measured: 4 weeks
Urine Doxycycline Concentration
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within urine samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 May 2024
- Study start18 Oct 2024
- Primary completion1 Sep 2028 (estimated)
- Study completion1 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sexually Transmitted Diseases, BacterialStudies of the same condition, open and under way.
- More trials run by University of California, San FranciscoThe 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
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Participants will be randomized to one of 4 doxycycline dosing patterns (daily, 3x weekly, weekly, every other week) and then will crossover to an alternate pattern once during the study.
- Masking
- None (open label)
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, San Francisco
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Matthew Spinelli, MD, MAS, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06414408
- Sponsor's protocol ID
- AI186641
- Other IDs
- R01AI186641
- Acronym
- DOT-Doxy-PEP
- Status last verified
- Sep 2026
- First submitted
- 9 May 2024
- Last updated
- 4 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Randomized Directly Observed Therapy Study to Interpret Clinical Trials of Doxy-PEP
- ClinicalTrials.gov ID
- NCT06414408
- Acronym / sponsor ID
- DOT-Doxy-PEP / AI186641
- Conditions
- Sexually Transmitted Diseases, Bacterial
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- University of California, San FranciscoUniversity, hospital or other
- Collaborators
- National Institute of Allergy and Infectious Diseases (NIAID)
- Study start
- 18 Oct 2024 (actual)
- Primary completion
- 1 Sep 2028 (estimated)
- Study completion
- 1 Dec 2028 (estimated)
- First posted
- 16 May 2024 (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.
Rates of bacterial sexually transmitted infections (STIs) are rising globally, demanding innovative interventions beyond the scope of current efforts to prevent STIs. The United States Doxycycline Post-exposure Prophylaxis (DoxyPEP) Study has demonstrated the efficacy of doxycycline post-exposure prophylaxis (PEP) among men who have sex with men and transgender women; but puzzlingly, doxycycline PEP was found ineffective in cisgender women in the Kenyan doxycycline Post-Exposure Prophylaxis (dPEP) study, with preliminary data suggesting the low medication adherence may explain the null result. By study end, the investigators will have developed adherence measurement methods for doxycycline in hair, blood, and urine, and will use these techniques to help interpret the Kenyan dPEP study, and to examine the relative performance of these methods within the United States DoxyPEP trial, establishing adherence metrics for current and future rollout studies of doxycycline post-exposure prophylaxis
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
- Model description
- Participants will be randomized to one of 4 doxycycline dosing patterns (daily, 3x weekly, weekly, every other week) and then will crossover to an alternate pattern once during the study.
| Arm | Type | Receives |
|---|---|---|
| Daily Dosing | Active comparator | Drug: Doxycycline PillParticipants will be randomized to take once daily doxycycline 200mg for six weeks. |
| Three-times Weekly Dosing | Active comparator | Drug: Doxycycline PillParticipants will be randomized to take one doxycycline 200mg dose three times a week (Monday, Wednesday, and Friday) for six weeks. |
| Weekly Dosing | Active comparator | Drug: Doxycycline PillParticipants will be randomized to take one doxycycline 200mg dose once week. |
| Every Other Week Dosing | Active comparator | Drug: Doxycycline PillParticipants will be randomized to take one doxycycline 200mg dose every other week. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- not currently at risk of a sexually transmitted infection and willing to use other methods, such as condoms, for STI prevention;
- if diagnosed with an STI in the past two years and/or a partner was diagnosed with an STI in the past year, is willing to use condoms for STI prevention;
- willing to provide hair, blood, and urine samples;
- not currently enrolled in other STI prevention studies;
- able to speak English
Key exclusion criteria (7 listed)
- any health condition that may interfere with participation or the ability to provide informed consent, including any debilitating or life-threatening conditions;
- pregnancy or plans to become pregnant;
- liver cirrhosis or fulminant liver disease;
- known hypersensitivity reaction to doxycycline.
- detectable doxycycline in hair at enrollment.
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 |
|---|---|---|
| Doxycycline Pill200mg Dose | Drug | Daily Dosing, Every Other Week Dosing, Three-times Weekly Dosing, Weekly Dosing |
Primary outcome
Hair Doxycycline Concentration
Time frame: 4 weeks
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within hair samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
Plasma Doxycycline Concentration
Time frame: 4 weeks
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within plasma samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
Urine Doxycycline Concentration
Time frame: 4 weeks
Doxycycline concentrations will be measured using liquid chromatography tandem mass spectrometry within urine samples for each of the four dosing patterns within an intensive washout pharmacokinetic phase following initial dosing.
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 4 Sep 2026.
- Individual participant dataSharing planned: No
Related trials for Sexually Transmitted Diseases, Bacterial
Recruiting
Bring BPaL2Me Trial Comparing Nurse-Led RR-TB Treatment to Physician-Led RR-TB Treatment
Drug Resistant Tuberculosis
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
Sexually Transmitted Infection (STI), Gonorrhea
Not yet recruiting
Optimizing Antibiotic Prescription in STI Clinics Using Rapid POCT
Chlamydia Trachomatis Infection, Neisseria Gonorrhoeae Infection
RecruitingPhase 4
Doxycycline Prophylaxis for Prevention of Sexually Transmitted Infections
Gonorrhea, Chlamydia
Not yet recruiting
Improving Clinic Delivery of HIV-related Anal Health Services
HIV, Gonorrhea
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.
Matthew Spinelli, MD, MAS principal investigator
University of California, San Francisco
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Doxycycline Pill in people with Sexually Transmitted Diseases, Bacterial, run by University of California, San Francisco 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 10 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 4 Sep 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?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
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 Shivani Mahuvakar (415-878-6384, DOTDoxyPEP@ucsf.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hair Doxycycline Concentration (time frame: 4 weeks). The study lists 3 primary outcomes in all. 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 4 Sep 2026.