← Back to Clinical Trials
Recruiting Phase 4 NCT06738407

NCT06738407 Doxycycline Prophylaxis for Prevention of Sexually Transmitted Infections

◆ AI Clinical Summary
Plain-language summary for patients
Clinical Trial Summary
NCT ID NCT06738407
Status Recruiting
Phase Phase 4
Sponsor Westat
Condition Gonorrhea
Study Type INTERVENTIONAL
Enrollment 760 participants
Start Date 2026-02-27
Primary Completion 2028-06-15

Eligibility & Interventions

Sex Female only
Min Age 13 Years
Max Age 29 Years
Study Type INTERVENTIONAL
Interventions
Doxycycline hyclate delayed released 200 mgDoxycycline hyclate delayed released 200 mg weeklyPer standard of care with quarterly STI testing/treatment and sexual health counseling

Eligibility Fast-Check

Enter your details for a quick preliminary check. This does not replace medical advice.

What to Expect as a Participant

You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.

Phase 4 studies follow an already-approved treatment in real-world conditions to monitor long-term safety and effectiveness.

This trial targets 760 participants in total. It began in 2026-02-27 with a primary completion date of 2028-06-15.

⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.

Brief Summary

The goal of this open-label, randomized trial is to assess the efficacy of doxycycline prophylaxis in reducing incidences of bacterial sexually transmitted infections (STIs) among adolescent and young adult females while also evaluating acceptability and antimicrobial resistance in order to inform public health policy.

Eligibility Criteria

Inclusion Criteria: * Age 13-29 years, inclusive; * Self-reports GC, CT, and/or early syphilis diagnosis in the 12 months prior to screening; * Self-reports condomless (oral, vaginal, and/or anal) intercourse at least once in the 30 days prior to screening * Is at least 45 kilograms (99.2 pounds) in weight * Fluent in English (able to read, speak, and understand English); * Willing to undergo all required study procedures; and * Willing to provide written informed consent to participate in the study. Exclusion Criteria: * Is male; * Is pregnant, breastfeeding, or planning to become pregnant in the next 12 months; * Documented history of tetracycline allergy or self-reports an allergy to tetracyclines; * Current or anticipated use of a medication (e.g., barbiturates, phenytoin, lithium, carbamazepine, systemic retinoids, warfarin) with a contraindicated interaction to doxycycline ; * Current or planned use of doxycycline for a prolonged period (\> 2 weeks) in the 30 days prior to enrollment, including current prescription for doxycycline for STI prophylaxis; * Prolonged antibiotic use (\> 2 weeks) within the last 30 days prior to enrollment; * Co-enrollment in any other concurrent interventional research or studies that may interfere with this study, such as an STI prevention trial, unless approved by Protocol Team in writing; * Does not have consistent access (or anticipated weekly access for 52 weeks of survey completion) to smartphone that can access the HMP app; or * Any other medical condition, medical/behavioral intervention, or other conditions that, in the opinion of the clinical site Project Lead (PL)/Investigator of Record (IoR) or designee, could interfere with adherence to study procedures or compromise interpretation of study results.

Contact & Investigator

Central Contact

Nancy Liu

✉ NancyLiu@westat.com

📞 718-980-3937

Principal Investigator

Cherie Blaire, MD, PhD

STUDY CHAIR

University of California, Los Angeles

Frequently Asked Questions

Who can join the NCT06738407 clinical trial?

This trial is open to female participants only, aged 13 Years or older, up to 29 Years, studying Gonorrhea. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.

What phase is the NCT06738407 trial and what does that mean for participants?

Phase 4 studies are conducted after a treatment has been approved. They monitor long-term safety and real-world effectiveness in a broader patient population.

Is NCT06738407 currently recruiting?

Yes, NCT06738407 is actively recruiting participants. Contact the research team at NancyLiu@westat.com for enrollment information.

Where is the NCT06738407 trial being conducted?

This trial is being conducted at Los Angeles, United States, San Francisco, United States, Washington D.C., United States, Tampa, United States and 9 additional locations.

Who is sponsoring the NCT06738407 clinical trial?

NCT06738407 is sponsored by Westat. The principal investigator is Cherie Blaire, MD, PhD at University of California, Los Angeles. The trial plans to enroll 760 participants.

Related Trials

ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer  ·  Last Reviewed: April 2026  ·  Data Methodology