Duchenne Muscular Dystrophy Case Study

RARE PEDIATRIC DISEASE DESIGNATION FOR THE POTENTIAL TREATMENT OF DUCHENNE MUSCULAR DYSTROPHY

Duchenne muscular dystrophy (DMD) is a serious and rare genetic disorder characterized by progressive muscle degeneration and weakness, primarily affecting boys. According to the Centers for Disease Control and Prevention, 15 out of every 100,000 males, aged between 5 and 24 years are affected. Symptoms usually start appearing in early childhood between 3 and 5 years of age. Gradually, the disease progresses with the weakening of skeletal or voluntary muscles in the arms, legs, and trunk. Due to this progressive muscle weakness, often the patients become bound to the wheelchair at an early age. Usually scoliosis surgery and/ or physical therapeutic measures such as physiotherapy or glucocorticoids are recommended for slowing disease progression and to offer symptomatic relief. However, due to the unavailability of disease-modifying treatment,

has developed an investigational drug called drisapersen for the treatment of DMD. This drug aims to treat 13% of the patients who are responsive to exon 51 skipping treatment. This represents the largest subpopulation of DMD patients, including patients with deletions of exon 50, exon 52, exons 45-50, exons 48-50, and exons 49-50. DMD is caused by the mutations in the dystrophin protein gene. Mutations are, mostly, deletions of one or more exons that interrupt the open reading frame of the transcript and eventually stop the synthesis of the dystrophin protein. Drisapersen, an RNA-modulating therapy, skips the exon 51 in dystrophin pre-mRNA. By skipping one or more exon(s), there is re-establishment of the open reading frame, followed by production of novel shortened dystrophin. By the production of dystrophin, the severity of Duchenne is reduced and it is converted into a milder Becker Muscular Dystrophy