Doxycycline Prophylaxis for Prevention of Sexually Transmitted Infections

Westat

Status and phase: Suspended; Phase 4

Conditions: Syphilis; Gonorrhea; Chlamydia; Sexually Transmitted Infections (STIs)

Treatments: Drug: Doxycycline hyclate delayed released 200 mg weekly; Drug: Doxycycline hyclate delayed released 200 mg

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT06738407

UM2HD111076 (U.S. NIH Grant/Contract)

ATN173/HPTN 115

Details and patient eligibility

About

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.

Full description

Participants will be randomized to receive on-demand doxycycline post-exposure prophylaxis (doxyPEP), weekly doxycycline, or standard of care (SOC) and will be followed quarterly to assess the impact of doxycycline use on the quarterly incidence of STIs (gonorrhea [GC], chlamydia [CT], and early syphilis), and within the doxycycline arms adherence and acceptability of weekly versus on-demand dosing.

Approximately 760 females will be randomized 1:1:1 to (1) on-demand doxyPEP (doxycycline 200 mg as soon as possible and within 72 hours after any condomless oral, vaginal, and/or anal sex), (2) weekly doxycycline (doxycycline 200 mg weekly regardless of sexual activity), or (3) SOC (quarterly STI testing/treatment and sexual health counseling). Participants will complete quarterly study visits over the course of 1 year during which they will receive STI testing (GC, CT, and syphilis), complete surveys, undergo safety monitoring, provide specimens for objective markers of doxycycline adherence and other laboratory assessments, and provide specimens (vaginal and rectal swabs [participant self-collected or staff-collected if the participant prefers]) for future testing, such as microbiome analysis. Resistance testing will be conducted on Staphylococcus (S.) aureus and Neisseria (N.) gonorrhoeae isolates to evaluate for doxycycline and tetracycline resistance, respectively. Participants will also complete weekly assessments of sexual activity and doxycycline adherence via the HealthMpowerment (HMP) application (app).

Enrollment: 760 estimated patients

Sex: Female

Ages: 13 to 29 years old

Volunteers: No Healthy Volunteers

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;
• Reports 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.

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

---

760 participants in 3 patient groups

On-demand doxyPEP

Experimental group

Description:

Participants will take by mouth doxycycline 200 mg as soon as possible and within 72 hours after any condomless oral, vaginal, and/or anal sex in addition to standard of care STI testing/treatment and sexual health counseling.

Treatment:

Drug: Doxycycline hyclate delayed released 200 mg

Weekly doxycycline

Experimental group

Description:

Participants will take by mouth doxycycline 200 mg weekly regardless of sexual activity in addition to standard of care STI testing/treatment and sexual health counseling.

Treatment:

Drug: Doxycycline hyclate delayed released 200 mg weekly

Quarterly STI testing/treatment and sexual health counseling

No Intervention group

Description:

Participants will be followed per standard of care with quarterly STI testing/treatment and sexual health counseling.