Duchenne muscular dystrophy: double-blind randomized trial to find optimum steroid regimen

INTERVENTION: One of three steroid regimens: 1. Daily prednisone (0.75 mg/kg/day) 2. Intermittent prednisone (0.75 mg/kg/day, 10 days on, 10 days off) 3. Daily deflazacort (0.9 mg/kg/day) The study treatment will last for a minimum of 36 months for all participants, and a maximum of 60 months for those recruited into the trial first (since it is anticipated that it will take up to two years to recruit the 300 participants). The longer duration of blinded intervention and followup for those subjects recruited early is in anticipation of the continued longterm unblinded followup of the full cohort of subjects at the end of this five year study. CONDITION: Topic: Medicines for Children Research Network; Subtopic: All Diagnoses; Disease: Duchenne Muscular Dystrophy ; Nervous System Diseases ; Duchenne Muscular Dystrophy PRIMARY OUTCOME: Multivariate outcome measured six‐monthly SECONDARY OUTCOME: 1. Adverse Event profile ; 2. Regimen tolerance; 3. Scondary functional outcomes; ; Measured six‐monthly INCLUSION CRITERIA: 1. Evidence of signed and dated informed consent form indicating that the subject and his parents or guardian (according to local legislation) have been informed about all pertinent aspects of the study. The child might be asked to give his assent, possibly in writing, if considered intellectually capable, in line with the legal requirements in the participating countries and with the permission of the parent(s)/guardian(s). 2. Confirmed diagnosis of Duchenne muscular dystrophy defined as: Male with proximal weakness and a confirmed DMD mutation in the dystrophin gene (out of frame deletion OR point mutation OR duplication) OR absent/< 3% dystrophin on muscle biopsy (by immunohistochemistry or Western blot). 3. Male, Age >= 4 years and < 8 years 4. Ability to rise independently from floor, from supine to standing, as assessed at screening visit 5. Willingness and ability to comply with scheduled visits, drug administration plan and study procedures (incl