This study will help to determine whether a high-dose weekly course of prednisone therapy is safer than and at least as effective as daily dose therapy for people with Duchenne muscular dystrophy (DMD). Boys who are enrolled in this study should not have taken carnitine, other amino acids, creatine, glutamine, Coenzyme Q10 or any herbal medicines within the last three months. There will be a two-visit screening to take place in one week to ensure a reproducible manual muscle test. The subject will then be randomized and put into either the daily or weekly regimen. The duration of the study is twelve 28-day treatment cycles (approximately 12 months) with follow-up visits at month one, three and then every three months.

Duchenne muscular dystrophy (DMD) is the most common lethal inherited disorder worldwide. Despite the exponential increase in our understanding of the disorder since the discovery and characterization of the causative gene and its product dystrophin in 1987, current therapeutic management remains largely supportive. Awaiting a final genetic cure to be available in the future, further investments in developing better drug therapies for DMD remain important. The effect of a high dose prednisone regimen will be evaluated in comparison to a daily dose regimen in a multi-center, randomized, double-blind placebo-controlled 4-arm study. Ambulant children aged 4-10 years with an established DMD diagnosis will be studied. Patients will undergo 2 screening evaluations within 1 week. Patients will be randomized into treatment groups on the second screening visit, followed by a 12-month treatment period. During the treatment period, patients will be evaluated at monthly intervals. The primary endpoints are percentage change in average muscle strength score and QMT performance for specific muscle groups. Secondary endpoints include timed function tests, functional grades for arms and legs, and pulmonary function tests.

Inclusion Criteria:

• 4 to 10 years of age
• Ambulant
• Confirmed DMD Diagnosis
• Steroid naive
• Evidence of muscle weakness by MRC score or clinical functional evaluation
• Ability to provide reproducible QMT bicep score

Exclusion Criteria:

• History of significant concomitant illness or significant impairment of renal or hepatic function, or other contraindication to steroid therapy
• Symptomatic DMD carrier
• Positive PPD
• Lack of prior exposure to chickenpox or immunization
• Use of carnitine, glutamine, Coenzyme Q10, other amino acids or any herbal medications within the last 3 months
• History of symptomatic cardiomyopathy
• Prior attainment of quota for the age group in which the patient belongs