The Phase 3 PolarisDMD trial did not meet the primary endpoint. As a result, activities related to the development of edasalonexent have stopped including the CAT-1004-302 Open-Label Study of Edasalonexent in Boys With Duchenne Muscular Dystrophy

The GalaxyDMD study is a global Phase 3, open-label, treatment extension study to evaluate the safety, tolerability, and durability of effect in long-term dosing of edasalonexent in pediatric patients with a genetically confirmed diagnosis of DMD. Patients who completed CAT-1004-201 or CAT-1004-301 or siblings of these boys from 4-12 years of age (up to 13th birthday) will be enrolled.

Edasalonexent is an orally administered small molecule that inhibits NF-kB, which is a key link between loss of dystrophin and disease pathology and plays a fundamental role in the initiation and progression of skeletal and cardiac muscle disease in DMD.

The study includes a 104-week open-label treatment period with edasalonexent. Patients who completed CAT-1004-201 or CAT-1004-301 and eligible siblings of these boys will be enrolled in this trial.

For Patients who Completed CAT-1004-201 or CAT-1004-301:

Inclusion Criteria:

• Written consent/assent by patient and/or legal guardian as per regional and/or Institutional Review Board (IRB)/Independent Ethics Committee (IEC) requirements
• Completion of either CAT-1004-201 or CAT-1004-301

Exclusion Criteria:

• In the Investigator's opinion, unwilling or unable for any reason to complete all study assessments and laboratory tests and comply with scheduled visits, administration of drug, and all other study procedures

For Siblings of Patients who Completed CAT-1004-201 or CAT-1004-301:

Inclusion Criteria:

• Written consent/assent by patient and/or legal guardian as per regional and/or Institutional Review Board (IRB)/Independent Ethics Committee (IEC) requirements
• A sibling of a patient who completed either CAT-1004-201 or CAT-1004-301
• Diagnosis of DMD based on a clinical phenotype with increased serum creatine kinase (CK) and documentation of mutation(s) in the dystrophin gene known to be associated with a DMD phenotype
• Followed by a doctor or medical professional who coordinates Duchenne care on a regular basis and willingness to disclose patient's study participation with medical professionals

Exclusion Criteria:

• Use of oral corticosteroids at screening; use of inhaled, intranasal, and topical corticosteroids is permitted
• Use of another investigational drug, idebenone, or dystrophin-focused therapy within 4 weeks. Exception: Patients who are currently on or plan to initiate treatment with approved oligonucleotide exon-skipping therapies, and expected to continue treatment throughout the study, will be eligible
• Use of the following within 4 weeks prior to Day 1: immunosuppressive therapy, anticoagulants, cyclosporine, dihydroergotamine, ergotamine, fentanyl, alfentanil, pimozide, quinidine, sirolimus or tacrolimus
• Use of human growth hormone within 3 months prior to Day 1
• Other prior or ongoing significant medical conditions