Doxycycline treatment for chlamydial infection

A Phase 4 Study of a 3-Day vs. 7-Day Regimen of Doxycycline for the Treatment of Chlamydial Infection

This study is testing whether a shorter 3-day treatment of doxycycline for chlamydia works just as well as the standard 7-day treatment for both men and women.

Quick facts

• Phase: Phase 4
• Study type: Interventional
• Enrollment: 664 (estimated)
• Ages: 16 Years and up
• Sex: All
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) (NIH)
• Locations: 7 sites (Birmingham, Alabama and 6 other locations)
• Trial ID: NCT05840159 on ClinicalTrials.gov

What this trial studies

This Phase 4 trial evaluates the effectiveness of a 3-day versus a 7-day regimen of doxycycline for treating urogenital and rectal chlamydial infections. The study involves a randomized, blinded, active-controlled design with a minimum of 596 participants, including both women and men diagnosed with chlamydia. Participants will receive either a 3-day treatment with doxycycline and placebo or a full 7-day treatment, with follow-up testing to assess microbiologic cure rates at day 29. The trial aims to determine if the shorter regimen is as effective as the longer one.

Who should consider this trial

Good fit: Ideal candidates are individuals aged 16 and older with untreated urogenital or rectal chlamydia confirmed by a positive nucleic acid amplification test.

Not a fit: Patients with symptoms of pelvic inflammatory disease or other complications related to chlamydia may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a shorter, effective treatment option for chlamydial infections, improving patient adherence and reducing healthcare costs.

How similar studies have performed: Previous studies have shown success with doxycycline for treating chlamydial infections, making this approach a continuation of established treatment protocols.

Eligibility criteria

Inclusion Criteria:

1. Has untreated urogenital chlamydia (CT) (in women) or rectal CT (in men), diagnosed with a positive nucleic acid amplification test (NAAT) (point-of care or laboratory-based)\* result within 14 days

   \*Point-of-care (POC) test may or may not be FDA-cleared for CLIA waiver for diagnosis depending upon anatomic site of infection.
2. Must be age \>/=16 years (where the IRB permits individuals aged 16-17 years old to consent to research); otherwise age \>/= 18 years
3. Willing and able to understand and provide written informed consent before initiation of any study procedures
4. Willing to complete a 7-day study drug regimen
5. Willing to abstain from condomless anal or vaginal sex during the trial
6. Willing and able to adhere to planned study procedures for all study visits
7. Has valid contact information

Exclusion Criteria:

1. For women: lower abdominal or pelvic pain or other signs or symptoms consistent with a clinical diagnosis of pelvic inflammatory disease (PID) Per the CDC's 2021 STD Treatment Guidelines or refer to local guidelines.
2. Signs and symptoms that, in the judgement of a qualified clinician, warrant a prolonged course of treatment with doxycycline For example, 21 days of doxycycline for presumed lymphogranuloma venereum infection.
3. Received antimicrobial therapy active against C. trachomatis within 21 days prior to positive chlamydia (CT) test result, or between the positive chlamydia (CT) test result and study enrollment Use of the following antibiotics is exclusionary: doxycycline and related tetra- or glycylcyclines, macrolides (including azithromycin), fluoroquinolones, rifampin, quinupristin-dalfopristin, and linezolid. Note: Amoxicillin, penicillin, ceftriaxone, and other beta-lactam antibiotics are not considered exclusionary for this study.
4. Planning to take antimicrobial therapy active against chlamydia (CT) during the study period (e.g. doxycycline post-exposure prophylaxis, treatment for Mycoplasma genitalium infection, acne, or any other non-STI medical condition).
5. Currently enrolled in or plan to enroll in another study using antimicrobial therapy active against C. trachomatis during the study period
6. Pregnant or lactating, or plan to become pregnant within the study period
7. Known moderate to severe allergy to tetracyclines, excluding tetracycline-induced photosensitivity.
8. Plan to move or travel to another location that would preclude study follow-up appointments in clinic in the next 30 days
9. Use of a medication contraindicated to treatment with doxycycline within 7 days prior to enrollment or during the study period (systemic retinoids, barbiturates, carbamazepine, phenytoin, warfarin)
10. Previous enrollment in this trial
11. Any condition that, in the judgment of the investigator, precludes participation because it could affect participant safety or determination of study endpoints.

Of note, the following factors will NOT exclude participants from the study:

* Concomitant untreated gonorrhea (rectal, pharyngeal, or urethral) or known exposure to gonorrhea in the time between CT testing and study enrollment. Gonococcus (GC) infection identified during the course of pre-screening or screening will be treated per clinic standard practice and in accordance with local guidelines without concomitant azithromycin or other treatment for Chlamydia trachomatis infection.
* Clinical diagnosis of concomitant untreated primary or secondary syphilis or known exposure to syphilis
* Urethritis among men
* Contraception status
* Diagnosis of HIV

Where this trial is running

Birmingham, Alabama and 6 other locations

• University of Alabama at Birmingham School of Medicine - Infectious Disease — Birmingham, Alabama, United States (Recruiting)
• Grady Memorial Hospital — Atlanta, Georgia, United States (Recruiting)
• Emory University Hospital Midtown - Emory Clinic Infectious Diseases — Atlanta, Georgia, United States (Recruiting)
• University of Rochester Medical Center - Vaccine Research Unit — Rochester, New York, United States (Recruiting)
• University of Washington - Harborview Medical Center - Center for AIDS and STD — Seattle, Washington, United States (Recruiting)
• Pwani Research Centre — Mombasa, Kenya (Recruiting)
• KEMRI-CCR PHRD Project — Thika, Kenya (Recruiting)

Study contacts

• Study coordinator: Julia C. Dombrowski

Conditions Chlamydial Infection; Chlamydia; Doxycycline; Infection; intervention; Phase 4