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Evaluation of Doxycycline Post-exposure Prophylaxis to Reduce Sexually Transmitted Infections in PrEP Users and HIV-infected Men Who Have Sex With Men

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03980223
Recruitment Status : Unknown
Verified May 2022 by University of California, San Francisco.
Recruitment status was:  Active, not recruiting
First Posted : June 10, 2019
Last Update Posted : May 25, 2022
University of Washington
National Institute of Allergy and Infectious Diseases (NIAID)
Mayne Pharma International Pty Ltd
San Francisco Department of Public Health
Information provided by (Responsible Party):
University of California, San Francisco

Brief Summary:
The purpose of this study is to understand if taking an antibiotic called doxycycline by mouth as soon as possible after sexual contact without a condom can reduce the risk of sexually transmitted infections (STIs), including gonorrhea, chlamydia and syphilis. The study will also look at the safety of doxycycline PEP and the impact that PEP may have on the bacteria that cause STIs as well as on bacteria that normally live on the body. While doxycycline is approved by the Food and Drug Administration (FDA), taking doxycycline immediately after sexual contact to prevent infection is investigational and is not approved by the FDA for this use. Participants will take part in the study for 1 year.

Condition or disease Intervention/treatment Phase
Gonorrhea Chlamydia Syphilis Drug: Doxycycline Hyclate Delayed-Release 200 mg Phase 4

Detailed Description:

The overarching goal is to assess the effectiveness of doxycycline PEP on incidence of STIs and tetracycline resistance among STIs and commensal bacteria to inform public health policy. Participants will be randomized 2:1, with a greater number receiving doxycycline PEP compared with the standard of care control, to maximize data on safety, tolerability, adherence coverage of sexual acts, and resistance data in participants randomized to doxycycline PEP, without negatively impacting power to measure effectiveness. Participants will be counseled about the preliminary effectiveness data from IPERGAY, and the potential for antimicrobial resistance (AMR) in STIs or other bacteria. Possibility of unreported doxycycline us in the control arm (contamination) will be monitored through retrospective batch testing of doxycycline metabolites in hair, to detect doxycycline use in the prior 3 months. 53

Eligible participants randomized 2:1 to receive PEP will receive open-label doxycycline 200 mg to be taken ideally within 24 hours but no later than 72 hours after condomless sexual contact (oral or anal). 200 mg of doxycycline will be taken at most once per 24 hour period regardless of the number of sexual acts occurring during this time period. Sexual activity will be recorded for both arms of the study (doxycycline PEP and control condition) by the participant using a smartphone application that will be adapted for study use; this will enable comparable assessment of risk in the two arms. PEP pill-taking will also be measured by the app to enable assessment of coverage of sex acts by PEP. Sexual activity and adherence will also be assessed in person at quarterly visits. STI testing will be conducted quarterly from three anatomic sites (pharyngeal, rectal and urinary) and blood for syphilis testing. Participants with a positive STI test will return for STI treatment and for swabs of the affected site for resistance testing; culture based for gonorrhea (GC) and molecular methods for CT and syphilis. Those with a serologic test that indicates a new syphilis infection will have swabs of any current active lesion as well as mucosal swabs from the oropharynx. Nares and oropharyngeal swabs will be obtained at baseline, 6 and 12 months to evaluate tetracycline resistance in S. aureus among carriers and in commensal Neisseria species.

Stool samples from 100 participants on the doxycycline PEP arm - 50 MSM living with HIV and 50 HIV uninfected MSM on pre-exposure prophylaxis (PrEP) - will be collected at baseline, 6 and 12 months to evaluate effects of intermittent doxycycline on the gut resistome, using 16s ribosomal RNA amplification to study tetracycline resistance genes. Rectal swabs will be collected and archived in all participants at baseline, 6, and 12 months for future studies of the impact of doxycycline PEP on the enteric microbiome and resistome.

Study population: This study will enroll 390 HIV-infected participants and 390 persons taking PrEP, for a total sample size of 780. An approximately equal number of participants in each of these cohorts (and in each study arm) will be enrolled in San Francisco and Seattle.

Current or planned initiation of PrEP use is an eligibility criterion for enrollment, because this population of MSM has high rates of STIs and are typically seen quarterly for PrEP visits. However, participants may opt to stop PrEP use at any time during the study without affecting their involvement in the study. Any HIV-uninfected participants who subsequently seroconvert will be managed clinically by the study site according to local practice (appropriate counseling, clinical evaluation and immediate linkage to clinical and psychosocial services). These participants will also be retained in the study unless they choose to discontinue study participation.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 637 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: Open-label randomized clinical trial
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: Evaluation of Doxycycline Post-exposure Prophylaxis to Reduce Sexually Transmitted Infections in PrEP Users and HIV-infected Men Who Have Sex With Men
Actual Study Start Date : November 26, 2019
Estimated Primary Completion Date : May 13, 2023
Estimated Study Completion Date : May 13, 2023

Arm Intervention/treatment
Experimental: Doxy PEP
Doxycycline 200mg in addition to standard of care STI testing and treatment
Drug: Doxycycline Hyclate Delayed-Release 200 mg
200 mg of doxycycline taken by mouth after condomless sexual contact as post exposure prophylaxis (PEP)

No Intervention: Control
The control arm will consist of standard of care STI testing and treatment

Primary Outcome Measures :
  1. Incidence of GC, CT or syphilis [ Time Frame: 1 year ]
    Combined incidence of GC, CT, or early syphilis infection by by laboratory-based diagnosis

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Willing and able to give written informed consent
  • Age ≥ 18 years
  • Male sex at birth
  • Previously HIV-diagnosed OR HIV-seronegative at the time of last test within the past month and a current prescription for PrEP (both daily or event-driven permitted) or plan to start PrEP within 30 days after the enrollment visit
  • Condomless anal or oral sexual contact with ≥ 1 male sex-at-birth partners in the past 12 months
  • Diagnosed with GC, CT or early syphilis (primary, secondary or early latent) in the past 12 months. Note: self report of STI is acceptable if documentation not available. If the participant reports an incident STI in the past year at the same clinic where the participant will be enrolled, this diagnosis should be confirmed by chart review prior to enrollment. If the diagnosis from this clinic cannot be confirmed, the participant should not be enrolled. If the STI was reported at a clinical site that is not the study site, and records cannot be obtained, self-report will suffice.

Note: Syphilis diagnosis within the last year refers to primary syphilis, secondary syphilis, and documented early latent syphilis (< 1 year since last syphilis diagnosis or negative test). Known late latent syphilis or latent syphilis of unknown duration would not qualify. Positive syphilis titers which represent serofast status and not active disease do not qualify as a syphilis diagnosis. Clinician judgement regarding qualifying syphilis diagnosis should be sought when the diagnosis of syphilis in the past year is not clear or if there is a question about serofast status vs. active infection.

Exclusion Criteria:

  • Allergy to tetracycline class
  • Current medications which may impact doxycycline metabolism or that are contraindicated with doxycycline, as per the prescribing information. These include systemic retinoids, barbiturates, carbamazepine, and phenytoin.
  • Current use of warfarin, as intermittent doxycycling use can lead to an unpredictable impact on INR
  • Anticipated use of doxycycline during the coming 12 months for non-STI prevention (e.g., acne treatment).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03980223

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United States, California
San Francisco City Clinic / San Francisco Department of Public Health
San Francisco, California, United States, 94103
University of California, San Francisco / Zuckerberg San Francisco General Hospital/UCSF
San Francisco, California, United States, 94110
United States, Washington
University of Washington
Seattle, Washington, United States, 98195
Sponsors and Collaborators
University of California, San Francisco
University of Washington
National Institute of Allergy and Infectious Diseases (NIAID)
Mayne Pharma International Pty Ltd
San Francisco Department of Public Health
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Principal Investigator: Anne Luetkemeyer, MD University of California, San Francisco

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Responsible Party: University of California, San Francisco Identifier: NCT03980223    
Other Study ID Numbers: DoxyPEP
R01AI143439 ( U.S. NIH Grant/Contract )
First Posted: June 10, 2019    Key Record Dates
Last Update Posted: May 25, 2022
Last Verified: May 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: IPD will not be shared with other researchers outside of the study team

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by University of California, San Francisco:
Post-Exposure Prophylaxis
Men who have sex with men (MSM)
HIV Pre-Exposure Prophylaxis
Sexually transmitted infection
Additional relevant MeSH terms:
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Sexually Transmitted Diseases
Gram-Negative Bacterial Infections
Bacterial Infections
Bacterial Infections and Mycoses
Sexually Transmitted Diseases, Bacterial
Communicable Diseases
Genital Diseases
Urogenital Diseases
Neisseriaceae Infections
Disease Attributes
Pathologic Processes
Treponemal Infections
Spirochaetales Infections
Anti-Bacterial Agents
Anti-Infective Agents
Antiprotozoal Agents
Antiparasitic Agents