Oral Ifetroban in Subjects With Duchenne Muscular Dystrophy

Open to males ages 7 years and up

1. Males 7 years of age and older with the diagnosis of DMD, defined as phenotype consistent with DMD and either positive genotype, first degree relative with positive genotype, or confirmatory muscle biopsy.
2. Stable dose of oral corticosteroids for at least 8 weeks or has not received corticosteroids for at least 30 days.
3. Stable cardiac function defined as change in left ventricular ejection fraction (LVEF) of < 15% and no heart failure admission over the last 12 months; LVEF 35% or greater by cine cardiac magnetic resonance imaging (MRI) or echocardiography; myocardial damage in one or more left ventricular segments evident by late gadolinium enhancement allowed; concurrent angiotensin-converting enzyme inhibitors (ACEI), beta-blocker (BB) or angiotensin receptor blocker (ARB) therapy allowed (selection of which dictated by clinical care) if started three months or greater from first dose of IMP without change in dose. Aldosterone receptor antagonists (eg. Spironolactone or eplerenone) allowed if started 12 months or greater from first dose of Investigational Medicinal Product (IMP). No changes throughout the study allowed, except in the event of a decline in left ventricular ejection fraction (LVEF) >5% following the baseline CMR as measured by a subsequent CMR at the same center. Should this occur, changes in cardiac medications are allowed on the study.
   1. Late-stage cohort: Subjects are eligible for the late-stage cohort if the subject has: i. LVEF 35%-45% by cine cardiac magnetic resonance imaging (MRI) or echocardiography or ii. historically documented LVEF 35%-45% by cine cardiac magnetic resonance imaging (MRI) or echocardiography and if their baseline MRI is less than 50%.
4. Subjects aged 18 years and older, informed consent obtained directly. For subjects ages 7-17 years old (yo), both assent from the subject and permission from a parent or guardian.

1. Clinically significant illness other than DMD
2. Clinically significant laboratory abnormality not associated with DMD
3. Major surgery within six weeks prior to the first dose of study drug, or planned surgery during this study which would interfere with the ability to perform study procedures
4. Require antiarrhythmic therapy and/or initiation of diuretic therapy for management of acute heart failure in the last 6 months
5. A LVEF of < 35% by Cardiac Magnetic Resonance Imaging (CMR) and/or fractional shortening of < 15% based on echocardiography (ECHO) during screening
6. A known bleeding disorder or has received anticoagulant treatment within 2 weeks of study entry
7. Allergy to gadolinium contrast or known renal insufficiency defined as abnormal cystatin C or creatinine above the upper limit of normal for age. The male serum reference ranges as follows:
   • Age 7-9 years - 0.2-0.6 mg/dL
   • Age 10-11 years - 0.3-0.7 mg/dL
   • Age 12-13 years - 0.4-0.8 mg/dL
   • Age 14-15 years - 0.5-0.9 mg/dL
   • Age 16 years or older - 0.8-1.3 mg/dL
8. Non-MR compatible implants (e.g. neurostimulator, automatic implantable cardioverter-defibrillator [AICD])
9. Subjects who participated in a therapeutic clinical trial within 30 days or five half-lives (whichever is longer) of study entry
10. Any other condition that could interfere with the subject's participation