Study of DS-5141b in Patients With Duchenne Muscular Dystrophy

Phase I/II Study of DS-5141b: Open-label Study of DS-5141b in Patients With Duchenne Muscular Dystrophy

This is a phase I/II study to evaluate the safety, tolerability, efficacy, and pharmacokinetic (PK) profile of DS-5141b in patients with Duchenne muscular dystrophy (DMD) amenable to exon 45 skipping and to determine the dosage for subsequent studies.

Inclusion Criteria:

• Confirmation of out-of-frame deletion(s) that could be corrected by dystrophin gene exon 45 skipping.
• Intact muscles of adequate quality for biopsy to allow evaluation of the efficacy of the study drug.
• Boys aged from 5 years to <11 years.
• Patients able to walk at least 325 meters in the 6-minutes walk test.
• Glucocorticoid-naive patients, or patients who have used glucocorticoids for at least 6 months prior to enrollment in this study with no dose changes for at least 3 months prior to enrollment.

Exclusion Criteria:

• A genetic mutation that can not be expected the expression of dystrophin protein by dystrophin gene exon 45 skipping.
• A concurrent illness other than DMD that can cause muscle weakness and/or impairment of motor function.
• Current or history of severe disorder.
• Left ventricular ejection fraction (LEVF) <55%.
• Corrected QT interval (QTc) >0.45 sec.