Doxycycline vs. Macrolide for MRMP (DOMINO) (DOMINO)

December 24, 2025 updated by: Young June Choe

Efficacy and Safety of Doxycycline Versus Macrolides for Mycoplasma Pneumoniae Infection in Children (DOMINO): A Protocol for a Multicenter, Randomized, Open-Label, Superiority Trial

The goal of this clinical trial is to learn if doxycycline works to treat pneumonia in children. It focuses on children with Mycoplasma pneumoniae infection that may not respond to standard medicines. The main questions it aims to answer are:

  • Does doxycycline stop fevers faster than azithromycin?
  • Is doxycycline safe for children, specifically regarding tooth color changes?

Researchers will compare doxycycline to azithromycin to see if doxycycline works better to treat this type of pneumonia.

Participants will:

  • Take either doxycycline or azithromycin by mouth for 7 to 14 days.
  • Check their body temperature to see when their fever goes away.
  • Visit the hospital to check for any medical problems.
  • Have their teeth checked for color changes 28 days after starting the medicine.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

208

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • South Korea
      • Busan, South Korea
        • Department of Pediatrics, Pusan National University School of Medicine, Pusan National University Children's Hospital, Yangsan, Republic of Korea
        • Contact:
      • Changwon, South Korea
        • Department of Pediatrics, Gyeongsang National University College of Medicine, Gyeongsang National University Changwon Hospital, Changwon, Republic of Korea
        • Contact:
      • Gwangju, South Korea
        • Department of Pediatrics, Chosun University College of Medicine, Chosun University Hospital, Gwangju, Republic of Korea
        • Contact:
      • Jeju City, South Korea
        • Department of Pediatrics, Jeju National University School of Medicine, Jeju National University Hospital, Jeju, Republic of Korea
        • Contact:
      • Seongnam, South Korea
        • Department of Pediatrics, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam, Republic of Korea
        • Contact:
      • Seongnam, South Korea
        • Department of Pediatrics, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, College of Medicine, The Catholic University of Korea, Eunpyeong St. Mary's Hospital, Seoul, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, Eulji University School of Medicine, Eulji University Hospital, Seoul, Republic of Korea
        • Contact:
          • Byung Wook Eun, MD
          • Phone Number: +82-10-5943-0133
      • Seoul, South Korea
        • Department of Pediatrics, Korea University College of Medicine, Korea University Anam Hospital, Seoul, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, Korea University College of Medicine, Korea University Guro Hospital, Seoul, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, Seoul National University College of Medicine, Seoul National University Children's Hospital, Seoul, Republic of Korea
        • Contact:
      • Seoul, South Korea
        • Department of Pediatrics, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age: 3 to 17 years at the time of enrollment.
  • Diagnosis: Clinically diagnosed CAP characterized by respiratory symptoms (e.g., fever, cough, auscultatory findings) and chest X-ray confirming pulmonary infiltrates.
  • Pathogen: Confirmed MP M. pneumoniae infection via PCR OR strongly suspected infection based on clinical features and epidemiological grounds (e.g., outbreaks among classmates, poor response to prior non-macrolide antibiotics).
  • Resistance: Suspected macrolide-resistant M. pneumoniae (MRMP) infection (e.g., during a reported local epidemic of MRMP).
  • Timing: Ability to register and initiate the study drug within 72 hours of symptom onset.

Exclusion Criteria:

  • Prior use of tetracyclines, macrolides, or quinolones for the current illness.
  • Complicated pneumonia (e.g., necrosis, empyema, lung abscess) or severe pneumonia requiring immediate intensive care or exhibiting hypoxia (SpO₂ <90%).
  • Hypersensitivity or contraindications to macrolides or tetracyclines.
  • Severe immunocompromised state or severe underlying lung disease.
  • Severe hepatic impairment (AST/ALT >3x upper limits) or severe renal impairment.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intervention Group (Doxycycline)
Participants will receive oral doxycycline (4 mg/kg/day divided into 2 doses for weight ≤45 kg; 100 mg BID for weight >45 kg). The standard treatment duration is 7 days, which may be extended up to 14 days based on clinical response.
Drug: Doxycycline
Intervention Group (Doxycycline): Participants will receive oral doxycycline (4 mg/kg/day divided into 2 doses for weight ≤45 kg; 100 mg BID for weight >45 kg). The standard treatment duration is 7 days, which may be extended up to 14 days based on clinical response.
Active Comparator: Control Group (Azithromycin)
Participants will receive oral azithromycin according to the standard 5-day regimen (10 mg/kg on Day 1, followed by 5 mg/kg on Days 2-5).
Drug: Azithromycin

Control Group (Azithromycin): Participants will receive oral azithromycin according to the standard 5-day regimen (10 mg/kg on Day 1, followed by 5 mg/kg on Days 2-5).

Rescue Therapy Protocol: To ensure patient safety, a standardized "rescue therapy" protocol is implemented. Participants in the Control group who fail to demonstrate clinical improvement at the 48-72 hour assessment-defined as persistent fever (≥38.0°C) or clinical deterioration-will be immediately switched to doxycycline. Consistent with the intention-to-treat principle, these cases will be classified as treatment failures for the primary efficacy analysis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Defervescence rate
Time Frame: 72 hours
Defervescence rate at 72 hours. Defervescence is defined as the maintenance of body temperature below 38.0°C for at least 24 consecutive hours without antipyretics.
72 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hospitalization Rate
Time Frame: Up to 30 days
Percentage of participants requiring hospitalization due to the progression of pneumonia or complications.
Up to 30 days
Length of Hospital Stay
Time Frame: Up to 30 days
The duration of hospitalization from admission to discharge.
Up to 30 days
Hospital Readmission Rate
Time Frame: Up to 30 days
Percentage of participants readmitted to the hospital after initial discharge due to worsening of pneumonia.
Up to 30 days
Treatment Failure Rate at Day 7
Time Frame: 7 days
Treatment failure is defined as the occurrence of any of the following: need for rescue therapy (switching to doxycycline for the control group), addition of other antibiotics or systemic steroids, or clinical deterioration requiring intensive care unit (ICU) admission.
7 days
Time to Resolution of Respiratory Symptoms
Time Frame: Up to 30 days
Time to resolution of respiratory symptoms (cough, dyspnea) assessed using a 4-point Likert scale. Resolution is defined as the point at which the symptom score reaches 0 (none) or 1 (mild) and is maintained
Up to 30 days
Time to Radiological Resolution of Infiltrates
Time Frame: Up to 30 days
Time to resolution of pulmonary infiltrates as confirmed by chest radiography follow-up.
Up to 30 days
Incidence of Tooth Discoloration in Children Under 8 Years
Time Frame: Day 28
Assessment of visible tooth discoloration evaluated by visual inspection.
Day 28

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Young June Choe

Collaborators

Korea Society of Pediatric Infectious Diseases
Korea National Institute of Health
Korea Disease Control and Prevention Agency
DT&CRO

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 1, 2026

Primary Completion (Estimated)

January 31, 2029

Study Completion (Estimated)

February 28, 2029

Study Registration Dates

First Submitted

December 22, 2025

First Submitted That Met QC Criteria

December 24, 2025

First Posted (Actual)

December 29, 2025

Study Record Updates

Last Update Posted (Actual)

December 29, 2025

Last Update Submitted That Met QC Criteria

December 24, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DOMINO
  • KNIH (Other Grant/Funding Number: National Institute of Health, Korea Disease Control and Prevention Agency)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (IPD) that underlie the results reported in the publication will be made available to researchers who provide a methodologically sound proposal. This includes text, tables, figures, and appendices. IPD will be available beginning 6 months and ending 36 months following article publication.

Supporting Information: The study protocol, statistical analysis plan (SAP), and informed consent form will also be shared. Access Criteria: Proposals should be directed to the Principal Investigator at [Insert Official Email Address]. To gain access, data requestors will need to sign a data access agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

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.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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