Background: Duchenne muscular dystrophy (DMD) is an X-linked disorder affecting 1:3500-5000 live male births, causing a life-limiting form of muscular dystrophy. Whole exon deletions disrupting the reading frame result in near-absence of sarcolemmal dystrophin, essential for muscle function. Eteplirsen is a phosphorodiamidate morpholino oligomer (PMO) designed to induce production of internally-truncated dystrophin in certain patients. Methods: As of June 2016, 150 patients (4-19 years of age) with DMD received eteplirsen in 7 clinical trials. 143 patients received ≥1 intravenous infusion of eteplirsen (range: 0.5 - 50 mg/kg). 81 (54%) received treatment for ≥1 year (Range: 1-4+ years). Results: Common (>15%) adverse events (AEs) were cough, headache, vomiting, back pain, extremity pain, contusion, nasopharyngitis, upper respiratory tract infection, nasal congestion, arthralgia and rash. Non-serious facial flushing, erythema and mild transient temperature elevation occurred with eteplirsen. 10 (6.7%) patients experienced severe AEs; 12 (8%) patients experienced serious AEs. All serious and all but 1 severe AEs were considered unrelated to eteplirsen by the treating physicians. Serial echocardiograms in 12 treated patients demonstrated no functional decline over 4+ years. Conclusions: Eteplirsen’s tolerability will continue to be assessed in ongoing clinical trials.

An updated data summary will be presented.