Phase 4 N=641 Randomized Prevention

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

Gonorrhea · Chlamydia · Syphilis

Bottom Line

View on ClinicalTrials.gov: NCT03980223 ↗

Enrolled (actual)

641

Serious AEs

0.9%

Results posted

Jul 2024

Primary outcome: Primary: Number of Quarterly Visits In Which an STI Was Detected — 61; 82; 36; 39 No. quarterly visits with STI event

Study Design & Population

Study type: Interventional
Phase: Phase 4
Interventions: Doxycycline Hyclate Delayed-Release 200 mg (Drug)
Age: Adult, Older Adult · 18+ yrs
Sex: Male
Sponsor: University of California, San Francisco
Primary completion: Jun 2023

Outcome Measures

Outcome	Result	p-value
PRIMARY Number of Quarterly Visits In Which an STI Was Detected	61; 82; 36; 39	—

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.

Eligibility Criteria

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).

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT03980223). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.