Conditions: Duchenne Muscular Dystrophy
Keywords: Duchenne muscular dystrophy Nonsense mutation Premature stop codon DMD PTC124 Ataluren
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 36
Healthy volunteers: no

Brief summary:
Duchenne muscular dystrophy (DMD) is a genetic disorder that develops in boys. It is caused by a mutation in the gene for dystrophin, a protein that is important for maintaining normal muscle structure and function. Loss of dystrophin causes muscle fragility that leads to weakness and loss of walking ability during childhood and teenage years. A specific type of mutation, called a nonsense (premature stop codon) mutation, is the cause of DMD in approximately 10-15% of boys with the disease. Ataluren is an orally-delivered, investigational drug that has the potential to overcome the effects of the nonsense mutation. This study is a Phase 2a extension trial that will evaluate the long-term safety of ataluren in boys with nonsense mutation DMD, as determined by adverse events and laboratory abnormalities. The study will also assess changes in walking, muscle function, strength, and other important clinical and laboratory measures.

Detailed description:
This Phase 2a, multicenter, open-label safety and efficacy study will be performed at 3 sites in the United States. The study will enroll up to 38 participants with nonsense mutation Duchenne muscular dystrophy who participated in a previous Phase 2a study of ataluren (Protocol Number PTC124-GD-004-DMD \[NCT00264888\]). Participants will receive study drug 3 times per day (at breakfast, lunch, and dinner) for approximately 96 weeks (approximately 2 years). Study assessments will be performed at clinic visits during screening, every 6 weeks for the first 24 weeks, and then every 12 weeks until the end of the study. Additional safety laboratory testing, which may be performed at the investigational site or at an accredited local laboratory or clinic, is required every 3 weeks for the first 24 weeks and then every 6 weeks from Week 24 to Week 48. Participants will have a biceps muscle biopsy before ataluren treatment and again after 24 weeks of ataluren treatment to evaluate changes in muscle dystrophin expression. An evaluation of the effects of ataluren on corticosteroid pharmacokinetics will be performed. Associated with this ataluren clinical trial is a substudy that will use magnetic resonance evaluations to assess changes in the composition of muscles of the legs.

Arms:
arm 1: Participants will receive ataluren 3 times per day with meals at doses of 20 milligrams per kilogram (mg/kg) (breakfast), 20 mg/kg (lunch), and 40 mg/kg (dinner) for up to 89 weeks.

Interventions: intervention 1: Ataluren
Intervention descriptions: intervention 1: Ataluren will be provided as a vanilla-flavored powder to be mixed with milk. Dosing based on participant body weight

Protocol document: