Duchenne Muscular DystrophyPhase 2FOXNCT06100887
Phase 2 Study of EDG-5506 in Children and Adolescents With Duchenne Muscular Dystrophy Previously Treated With Gene Therapy
A Phase 2 study testing Sevasemten Dose 1, Sevasemten Dose 2 and Sevasemten Dose 3 in people with Duchenne Muscular Dystrophy, run by Edgewise Therapeutics, Inc. at 7 sites in United States.
Trial summary
The FOX study is a 2-part, multicenter, Phase 2 study of safety, pharmacokinetics, and biomarkers in children and adolescents with Duchenne muscular dystrophy previously treated with gene therapy including a randomized, double-blind, placebo-controlled Part A, followed by an open-label part B. Read more about this study
- Who is it for?
- Ages 6 to 17 years, men only
- Conditions the study is for
- Duchenne Muscular Dystrophy
- What is being tested?
- Sevasemten Dose 1, Sevasemten Dose 2 and Sevasemten Dose 3
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 43 participants
- Where
- 7 sitesUnited States
- Study dates
- 22 Mar 2024to Mar 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 17 years
- Men only
- No healthy volunteers
- Child
Who may be able to join
- Aged 6 to 17 with a documented mutation on the DMD gene and phenotype consistent with DMD.
- Prior receipt of an AAV-based gene therapy (≥ 2 years after documented receipt of gene therapy administration or ≥ 3 years after randomization in a randomized study).
- Able to complete stand from supine in ≤ 8 seconds at the Screening visit and able to perform the 4-stair climb in < 10 seconds at the Screening visit.
- Body weight ≥ 15 kg at the Screening visit.
- Treatment with a stable dose of corticosteroids for a minimum of 6 months prior to the Baseline visit.
Who cannot join
- Medical history or clinically significant physical exam/laboratory result that, in the opinion of the investigator, would render the participant unsuitable for the study. This includes venous access that would be too difficult to facilitate repeated blood sampling.
- Screening visit cardiac echocardiography showing left ventricular ejection fraction (LVEF) < 40%.
- Receipt of an investigational drug (other than the AAV-based gene therapy per Inclusion criteria) within 30 days or 5 half-lives (whichever is longer) of the Screening visit in the present study.
- Receipt of an exon-skipping therapy within 6 months prior to the Screening visit.
Trial locations and contacts
7 sites in 1 country.
7 sites in 1 country
United States7 sites
Nationwide Children's Hospital
Columbus, Ohio, 43205
University of Florida
Gainesville, Florida, 32610
Rare Disease Research
Hillsborough, North Carolina, 27278
UCLA Medical Center
Los Angeles, California, 90095
UC Davis Medical Center
Sacramento, California, 95817
Washington University School of Medicine
St Louis, Missouri, 63110
University of Massachusetts Memorial Medical Center
Worcester, Massachusetts, 01605
About this study
Official title: A Phase 2 Study to Evaluate the Effect of EDG-5506 on Safety, Pharmacokinetics, and Biomarkers in Children and Adolescents With Duchenne Muscular Dystrophy Previously Treated With Gene Therapy
The FOX study is a 2-part, multicenter, Phase 2 study of safety, pharmacokinetics, and biomarkers in children and adolescents with Duchenne muscular dystrophy previously treated with gene therapy including a randomized, double-blind, placebo-controlled Part A, followed by an open-label part B.
Read the detailed description
FOX is a 2-part, multi-center, Phase 2 study to evaluate the effect of sevasemten (EDG-5506) on safety, pharmacokinetics and biomarkers of muscle damage in approximately 48 children and adolescents with Duchenne muscular dystrophy treated with oral, once-daily sevasemten. This study will have up to a 4-week Screening period, a 12-week randomized double-blind, placebo-controlled treatment period (Part A), followed by up to a 144-week open-label extension period (Part B).
Approximately forty-eight (48) participants aged 6 to 17, inclusive, will be randomized to sevasemten or placebo in a 2:1 ratio. Three dose cohorts (Cohort 1, Cohort 2 and Cohort 3) of approximately 12 participants each will be enrolled. Approximately 12 additional participants may be added to 1 of these cohorts.
After review of emerging data, the protocol was amended so all dose cohorts receive the same dose in Part B.
- Conditions
- Duchenne Muscular Dystrophy
- Being tested
- Sevasemten Dose 1, Sevasemten Dose 2, Sevasemten Dose 3, Placebo
- Keywords
- Duchenne Muscular Dystrophy
- Medical subject headings
- Muscular Dystrophy, Duchenne
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sevasemten Dose 1Drug
Sevasemten is administered orally once per day
Sevasemten Dose 2Drug
Sevasemten is administered orally once per day
Sevasemten Dose 3Drug
Sevasemten is administered orally once per day
PlaceboDrug
Placebo is administered orally once per day
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 | Experimental | Drug: Sevasemten Drug: Placebo Receives: Drug: Sevasemten Dose 1; Drug: Placebo |
| Cohort 2 | Experimental | Drug: Sevasemten Drug: Placebo Receives: Drug: Sevasemten Dose 2; Drug: Placebo |
| Cohort 3 | Experimental | Drug: Sevasemten Drug: Placebo Receives: Drug: Sevasemten Dose 3; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of adverse events during treatment with sevasemten or placebo
All participants
Measured: 36 months
Severity of adverse events during treatment with sevasemten or placebo
All participants
Measured: 36 months
Secondary outcomes (4)
Incidence of laboratory test-related treatment emergent adverse events
All participants
Measured: 36 months
Pharmacokinetics as measured by steady state plasma concentration
All participants
Measured: 36 months
Change from Baseline in serum creatine kinase
All participants
Measured: 12 weeks
Change from Baseline in fast skeletal muscle troponin I
All participants
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Oct 2023
- Study start22 Mar 2024
- Primary completionMar 2027 (estimated)
- Study completionMar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Duchenne Muscular DystrophyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 43 participants (actual)
Sponsor and investigators
- Lead sponsor
- Edgewise Therapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06100887
- Sponsor's protocol ID
- EDG-5506-215
- Acronym
- FOX
- Status last verified
- Nov 2025
- First submitted
- 20 Oct 2023
- Last updated
- 6 Nov 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2 Study to Evaluate the Effect of EDG-5506 on Safety, Pharmacokinetics, and Biomarkers in Children and Adolescents With Duchenne Muscular Dystrophy Previously Treated With Gene Therapy
- ClinicalTrials.gov ID
- NCT06100887
- Acronym / sponsor ID
- FOX / EDG-5506-215
- Conditions
- Duchenne Muscular Dystrophy
- Keywords
- Duchenne Muscular Dystrophy
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 43 participants (actual)
- Lead sponsor
- Edgewise Therapeutics, Inc.Industry (pharma, biotech, devices)
- Study start
- 22 Mar 2024 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Mar 2027 (estimated)
- First posted
- 25 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The FOX study is a 2-part, multicenter, Phase 2 study of safety, pharmacokinetics, and biomarkers in children and adolescents with Duchenne muscular dystrophy previously treated with gene therapy including a randomized, double-blind, placebo-controlled Part A, followed by an open-label part B.
Detailed description
FOX is a 2-part, multi-center, Phase 2 study to evaluate the effect of sevasemten (EDG-5506) on safety, pharmacokinetics and biomarkers of muscle damage in approximately 48 children and adolescents with Duchenne muscular dystrophy treated with oral, once-daily sevasemten. This study will have up to a 4-week Screening period, a 12-week randomized double-blind, placebo-controlled treatment period (Part A), followed by up to a 144-week open-label extension period (Part B).
Approximately forty-eight (48) participants aged 6 to 17, inclusive, will be randomized to sevasemten or placebo in a 2:1 ratio. Three dose cohorts (Cohort 1, Cohort 2 and Cohort 3) of approximately 12 participants each will be enrolled. Approximately 12 additional participants may be added to 1 of these cohorts.
After review of emerging data, the protocol was amended so all dose cohorts receive the same dose in Part B.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 | Experimental | Drug: Sevasemten Dose 1, Drug: PlaceboDrug: Sevasemten Drug: Placebo |
| Cohort 2 | Experimental | Drug: Sevasemten Dose 2, Drug: PlaceboDrug: Sevasemten Drug: Placebo |
| Cohort 3 | Experimental | Drug: Sevasemten Dose 3, Drug: PlaceboDrug: Sevasemten Drug: Placebo |
Who may qualify
- Ages
- 6 to 17 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (5 listed)
- Aged 6 to 17 with a documented mutation on the DMD gene and phenotype consistent with DMD.
- Prior receipt of an AAV-based gene therapy (≥ 2 years after documented receipt of gene therapy administration or ≥ 3 years after randomization in a randomized study).
- Able to complete stand from supine in ≤ 8 seconds at the Screening visit and able to perform the 4-stair climb in < 10 seconds at the Screening visit.
- Body weight ≥ 15 kg at the Screening visit.
- Treatment with a stable dose of corticosteroids for a minimum of 6 months prior to the Baseline visit.
Key exclusion criteria (4 listed)
- Medical history or clinically significant physical exam/laboratory result that, in the opinion of the investigator, would render the participant unsuitable for the study. This includes venous access that would be too difficult to facilitate repeated blood sampling.
- Screening visit cardiac echocardiography showing left ventricular ejection fraction (LVEF) < 40%.
- Receipt of an investigational drug (other than the AAV-based gene therapy per Inclusion criteria) within 30 days or 5 half-lives (whichever is longer) of the Screening visit in the present study.
- Receipt of an exon-skipping therapy within 6 months prior to the Screening visit.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Sevasemten Dose 1Sevasemten is administered orally once per day | Drug | Cohort 1 |
| Sevasemten Dose 2Sevasemten is administered orally once per day | Drug | Cohort 2 |
| Sevasemten Dose 3Sevasemten is administered orally once per day | Drug | Cohort 3 |
| PlaceboPlacebo is administered orally once per day | Drug | Cohort 1, Cohort 2, Cohort 3 |
Primary outcome
Number of adverse events during treatment with sevasemten or placebo
Time frame: 36 months
All participants
Severity of adverse events during treatment with sevasemten or placebo
Time frame: 36 months
All participants
4 secondary outcomes
Incidence of laboratory test-related treatment emergent adverse events
Time frame: 36 months
Pharmacokinetics as measured by steady state plasma concentration
Time frame: 36 months
Change from Baseline in serum creatine kinase
Time frame: 12 weeks
Change from Baseline in fast skeletal muscle troponin I
Time frame: 12 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2025.
- Sponsor WebsiteLink provided by the sponsor.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
7 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Sevasemten Dose 1, Sevasemten Dose 2 and Sevasemten Dose 3 in people with Duchenne Muscular Dystrophy, run by Edgewise Therapeutics, Inc. at 7 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 6 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 7 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of adverse events during treatment with sevasemten or placebo (time frame: 36 months). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2025; AzTrials last refreshed its copy on 8 Nov 2026.