Duchenne muscular dystrophy (DMD) is a severely disabling and fatal disorder. It is the most common muscular dystrophy, affecting 1:5000 boys worldwide; however, it is an orphan disease which has received relatively little investment toward the development of novel therapeutics. Consequently, there are no good treatments for this devastating disorder. In this application, Dr. Kathryn Wagner from the Kennedy Krieger Institute and Dr. Stanley Froehner from the University of Washington propose to repurpose a Sanofi compound for Duchenne muscular dystrophy. In the UH2 portion of the award, Dr. Froehner will test efficacy of the compound in the mdx/utr mouse model of DMD and will oversee juvenile toxicology studies performed by a CRO. Following timely IND filing with the FDA, Dr. Wagner and Dr. Jerry Mendell at Nationwide Children's Hospital will conduct Phase Ib SAD and MAD studies for safety and dose finding in a limited number of DMD subjects. In the UH3 portion of the award, Phase IIa studies in DMD boys will be conducted at multiple sites across the country. Investigators at all sites have active DMD clinics and experience in DMD clinical trials. The Phase IIa study will determine if the compound results in functional improvement in DMD as well as whether sustained administration is safe and well tolerated in DMD. Given the life threatening and disabling nature of DMD, the Phase IIa is anticipated to be the pivotal clinical trial for seeking provisional FDA approval.