A Study to Compare Safety and Efficacy of High Doses of Eteplirsen in Participants With Duchenne Muscular Dystrophy (DMD) (MIS51ON) (MIS51ON)

February 25, 2026 updated by: Sarepta Therapeutics, Inc.

A Randomized, Double-Blind, Dose Finding and Comparison Study of the Safety and Efficacy of High Doses of Eteplirsen, Preceded by an Open-label Dose Escalation, in Patients With Duchenne Muscular Dystrophy With Deletion Mutations Amenable to Exon 51 Skipping

Part 1 (dose escalation) will evaluate the safety and tolerability of 2 doses (100 milligrams/kilogram [mg/kg] and 200 mg/kg) of eteplirsen in approximately 10 participants with DMD; Part 2 (dose finding and dose comparison) will evaluate the efficacy and safety of the high doses (100 mg/kg and 200 mg/kg) of eteplirsen compared with that of the 30 mg/kg dose of eteplirsen, in approximately 144 participants with genetically confirmed deletion mutations amenable to treatment by skipping exon 51.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
160

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Sarepta Therapeutics Inc. For Clinical Trial Information, Select Option 4
  • Phone Number: 1-888-SAREPTA (1-888-727-3782)
  • Email: SareptAlly@sarepta.com

Study Locations

  • Colombia
      • Bogotá, Colombia, 110231
        • Hospital Universitario San Ignacio
      • Medellín, Colombia, 50012
        • Instituto Neurologico de Colombia (INDEC)
      • Medellín, Colombia, 50034
        • Hospital Pablo Tobon Uribe
  • Czechia
      • Brno, Czechia, 613 00
        • Brno Klinika detske neurologie
      • Prague, Czechia, 150 06
        • Fakultni nemocnice v Motole
  • Denmark
      • Copenhagen, Denmark, 2100
        • Rigshospitalet Copenhagen University Hospital
  • France
      • Bron, France, 69677
        • Hopital Femme Mere Enfant
      • Paris, France, 75571
        • Hôpital Armand Trousseau
      • Strasbourg, France, 67098
        • CHRU de Strasbourg
  • Germany
      • Berlin, Germany, 13353
        • Charité Universitätsmedizin Berlin CVK
      • Essen, Germany, 45147
        • Universitätsklinikum Essen
      • Freiburg im Breisgau, Germany, 79106
        • Universitätsklinikum Freiburg
  • Greece
    • Attica
      • Marousi, Attica, Greece, 151 23
        • IASO Children's Hospital
  • Hungary
      • Budapest, Hungary, 1082
        • Semmelweis Egyetem Genomikai Medicina és Ritka Betegsegek Intezete
  • India
      • Ahmedabad, India, 380054
        • Royal Institute of Child Neurosciences
      • Bengaluru, India, 560078
        • Aster RV Hospital
      • Hyderabad, India, 500082
        • Nizam's Institute of Medical Sciences
      • Madurai, India, 626022
        • Jaicare Hospital (A Unit of Sarvee Integra Pvt Ltd.)
      • New Delhi, India, 110029
        • All India Institute of Medical Sciences
      • New Delhi, India, 110060
        • Sir Ganga Ram Hospital
      • Pune, India, 411004
        • Deenanath Mangeshkar Hospital & Research Centre
      • Vellore, India, 632004
        • Christian Medical College
  • Ireland
      • Dublin, Ireland, D01 XD99
        • Children's Health Ireland (CHI) at Temple Street
  • Italy
      • Genova, Italy, 16147
        • IRCCS Instituto Gianna Gaslini
      • Rome, Italy, 00168
        • Fondazione Policlinico Universitario A. Gemelli- IRCCS
  • Jordan
      • Amman, Jordan, 11194
        • The Specialty Hospital (TSH)/Advanced Clinical Center
      • Amman, Jordan, 11196
        • Istiklal Hosptial (IST)
      • Irbid, Jordan, 22110
        • Irbid Specialty Hospital
      • Irbid, Jordan, 22110
        • Pharmaceutical Research Center/Jordan University of Science and Technology
  • Mexico
      • Durango, Mexico, 34000
        • Instituto de Investigaciones Clinicas para la Salud A.C
    • Sinaloa
      • Culiacán, Sinaloa, Mexico, 80020
        • Neurociencias Estudios Clinicos S.C.
  • Netherlands
      • Leiden, Netherlands, 2333 ZC
        • Leids Universitair Medisch Centrum
      • Nijmegen, Netherlands, 6525GA
        • Radboud University Nijmegen Medical Centre
  • New Zealand
      • Auckland, New Zealand, 1010
        • New Zealand Clinical Research - Auckland
  • Norway
      • Oslo, Norway, 0450
        • Oslo Universitetssykehus HF Rikshospitalet
      • Stavanger, Norway, 4011
        • Children's Department and Department for Children's Habilitation at Stavanger University Hospital
  • Poland
    • Pomeranian Voivodeship
      • Gdansk, Pomeranian Voivodeship, Poland, 80-211
        • Klinika Neurologii Rozwojowej
  • Romania
      • Bucharest, Romania, 41408
        • National Clinical Hospital for Children Neurorehabilitation "Dr. Nicolae Robănescu"
  • Serbia
      • Belgrade, Serbia, 11000
        • University Children's Hospital
      • Belgrade, Serbia, 11000
        • Clinic for Neurology and Psychiatry for Children and Youth
      • Belgrade, Serbia, 190133
        • Mother and Child Health Care Institute of Serbia "Dr Vukan Cupic"
  • Slovenia
      • Ljubljana, Slovenia, 1000
        • University Medical Centre Ljubljana
  • South Korea
      • Daegu, South Korea, 41404
        • Kyungpook National University Chilgok Hospital
      • Seoul, South Korea, 03080
        • Seoul National University Hospital
      • Seoul, South Korea, 6351
        • Samsung Medical Center
      • Yangsan, South Korea, 50612
        • Pusan National University Yangsan Hospital
  • Spain
      • Barcelona, Spain, 8950
        • Hospital Sant Joan de Déu
      • Valencia, Spain, 46026
        • Hospital Universitari i Politecnic La Fe de Valencia
  • Switzerland
      • Basel, Switzerland, 4031
        • Universitätsspital Basel
  • Taiwan
      • Kaohsiung City, Taiwan, 80756
        • Kaohsiung Medical University
      • Taipei, Taiwan, 10071
        • National Taiwan University Hospital
  • Turkey (Türkiye)
      • Antalya, Turkey (Türkiye), 07059
        • Akdeniz Universitesi Tip Fakultesi
      • Mersin, Turkey (Türkiye), 33110
        • Mersin University Medical Faculty
  • United Kingdom
      • Birmingham, United Kingdom, B9 5SS
        • Birmingham Heartlands Hospital
      • London, United Kingdom, WC1N 1EH
        • UCL Institute of Child Health Great Ormond Street
    • West Yorkshire
      • Leeds, West Yorkshire, United Kingdom, LS1 3EX
        • Leeds Teaching Hospitals NHS Trust
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • University of Alabama at Birmingham
    • Florida
      • Gainesville, Florida, United States, 32610-3010
        • University of Florida
    • Georgia
      • Atlanta, Georgia, United States, 30318
        • Rare Disease Research, LLC

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

4 years to 13 years (Child)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Be a male with an established clinical diagnosis of DMD and an out-of-frame deletion mutation of the DMD gene amenable to exon 51 skipping.
  • Ambulatory participant, able to perform TTRISE in 10 seconds or less at the time of screening visit.
  • Able to walk independently without assistive devices.
  • Have intact right and left biceps muscles or an alternative upper arm muscle group.
  • Have been on a stable dose or dose equivalent of oral corticosteroids for at least 12 weeks prior to randomization and the dose is expected to remain constant (except for modifications to accommodate changes in weight and stress-related needs as per the recently published guidelines throughout the study.
  • For ages 7 years and older, has stable pulmonary function (forced vital capacity ≥50 percent (%) of predicted and no requirement for nocturnal ventilation). For ages 4 to 6 years, does not require support from ventilator or non-invasive ventilation at time of screening.

Exclusion Criteria:

  • Use of any pharmacologic treatment (other than corticosteroids) within 12 weeks prior to randomization.
  • Current or previous treatment with any other experimental pharmacologic treatment for DMD or any prior exposure to antisense oligonucleotide, gene therapy or gene editing; except the following: Ezutromid in the last 12 weeks prior to first dose; Drisapersen in the last 36 weeks prior to first dose; Suvodirsen in the last 12 weeks prior to first dose; Vamorolone in the last 12 weeks prior to first dose; Eteplirsen (previous or current use); and Tamoxifen in the last 4 weeks prior to first dose.
  • Major surgery within 3 months prior to randomization.
  • Presence of any other significant neuromuscular or genetic disease other than DMD.
  • Presence of any known impairment of renal function and/or other clinically significant illness.
  • Has evidence of cardiomyopathy, as defined by left ventricular ejection fraction less than <50% on the screening echocardiogram or Fridericia's correction formula (QTcF) ≥450 millisecond based on the screening electrocardiograms (ECGs).

Other inclusion/exclusion criteria apply.

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: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Part 1: Eteplirsen
Participants will receive eteplirsen 100 mg/kg once weekly for at least 4 weeks, followed by eteplirsen 200 mg/kg once weekly for at least 4 weeks.
Drug: Eteplirsen
Solution for intravenous (IV) infusion.
Other Names:
  • AVI-4658
  • EXONDYS 51
  • EXONDYS
Active Comparator: Part 2: Eteplirsen 30 mg/kg
Randomized participants will receive eteplirsen 30 mg/kg once weekly for up to 144 weeks.
Drug: Eteplirsen
Solution for intravenous (IV) infusion.
Other Names:
  • AVI-4658
  • EXONDYS 51
  • EXONDYS
Experimental: Part 2: Eteplirsen 100 mg/kg
Randomized participants will receive eteplirsen 100 mg/kg once weekly for up to 144 weeks.
Drug: Eteplirsen
Solution for intravenous (IV) infusion.
Other Names:
  • AVI-4658
  • EXONDYS 51
  • EXONDYS
Experimental: Part 2: Eteplirsen 200 mg/kg
Randomized participants will receive eteplirsen 200 mg/kg once weekly for up to 144 weeks.
Drug: Eteplirsen
Solution for intravenous (IV) infusion.
Other Names:
  • AVI-4658
  • EXONDYS 51
  • EXONDYS

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Part 1: Incidence of Adverse Events (AEs)
Time Frame: Up to Week 148
Up to Week 148
Part 2: Change From Baseline at Week 144 in the NSAA Total Score (for Final Analysis)
Time Frame: Baseline, Week 144
Baseline, Week 144
Part 2: Change from Baseline at Week 72 or Week 96 in NSAA Total Score (for Conditional Efficacy Interim Analysis)
Time Frame: Baseline, Week 72 or Week 96
Baseline, Week 72 or Week 96

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Part 2: Change From Baseline in Time to Rise From the Floor, Time to Complete 10-Meter Walk/Run, and the Timed Stair Ascend Test
Time Frame: Baseline, Week 144
Baseline, Week 144
Part 2: Change From Baseline in the Total Distance Walked During 6-Minute Walk Test (6MWT)
Time Frame: Baseline, Week 144
Baseline, Week 144
Part 2: Time to Loss of Ambulation (LOA)
Time Frame: Baseline up to Week 144
Baseline up to Week 144
Part 2: Change From Baseline in Skeletal Muscle Dystrophin Expression
Time Frame: Baseline, Postdose (at Week 24, Week 48, or Week 144)
Baseline, Postdose (at Week 24, Week 48, or Week 144)
Part 2: Incidence of Adverse Events (AEs)
Time Frame: Baseline up to Week 148
Baseline up to Week 148
Part 2: Pharmacokinetic (PK) Plasma Concentration of Eteplirsen
Time Frame: 0 (predose) to 2 hours postdose up to Week 144
0 (predose) to 2 hours postdose up to Week 144
Part 2: Change from Baseline at Week 144 in Forced Vital Capacity Percent Predicted (FVC%p)
Time Frame: Baseline, Week 144
Baseline, Week 144

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sarepta Therapeutics, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Medical Director, Sarepta Therapeutics, Inc.

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.

Helpful Links

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 13, 2020

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 18, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 18, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 20, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 25, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 4658-402
  • 2018-001762-42 (EudraCT Number)
  • 2024-511492-15-00 (Registry Identifier: CTIS (EU))

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

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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