Oral Ifetroban in Subjects With Duchenne Muscular Dystrophy

This is a phase 2 randomized, double-blind, placebo-controlled, multiple dose study with an optional open-label extension to determine the safety, pharmacokinetics (PK) and efficacy of two doses of oral ifetroban in subjects with DMD. DMD patients who meet the inclusion criteria and none of the exclusion criteria will receive oral ifetroban or placebo once daily for 12 months. Subjects will be enrolled into one of three treatment groups, low-dose ifetroban, high-dose ifetroban or placebo. Each dose level will be evaluated by eight subjects with early stage (LVEF \> 45%) DMD-associated cardiomyopathy and eight subjects with more advanced stage (LVEF 35-45%) cardiac disease as there may be differences in the treatment effect based on cardiac involvement. Each subject treated will be evaluated for first-dose and steady-state exposure PK. All subjects who receive treatment will be assessed for safety. All subjects with at least one efficacy assessment post-baseline will be evaluated for efficacy. Blood and urine will be collected for standard and novel cardiac biomarkers. Target enrollment met for early-stage subjects (LVEF \> 45%); study closed to enrollment prior to meeting target enrollment in the late-stage cohort (LVEF 35-45%). All subjects who complete the 12-month study are eligible to enter an optional open label extension period consisting of treatment with high-dose ifetroban only. Subjects in the open label extension will be evaluated for safety and cardiac efficacy every 12 months.