Duchenne muscular dystrophy is a fatal X-linked disease characterized by the absence of dystrophin. Approximately 20% of boys will die of dilated cardiomyopathy that is associated with cytoskeletal protein disarray, contractile dysfunction, and reduced energy production. However, the mechanisms for altered energy metabolism are not yet fully clarified. Calcium influx through the L-type Ca2+ channel is critical for maintaining cardiac excitation and contraction. The L-type Ca2+ channel also regulates mitochondrial function and metabolic activity via transmission of movement of the auxiliary beta subunit through intermediate filament proteins.

Sarepta Therapeutics, Inc. (NASDAQ:SRPT), a developer of innovative RNA-based therapeutics, today announced data through Week 144 from Study 202, a Phase IIb open-label extension study of eteplirsen in patients with Duchenne muscular dystrophy (DMD). After nearly three years of follow up, results on the 6-minute walk test (6MWT) showed a decline in walking ability at a rate slower than would be expected based on available DMD natural history data.

Today, Summit released further results with new data from its recently completed Phase IB clinical trial of SMT C1100 at the 13th International Congress of Neuromuscular Disease in Nice, France.

Patients with Becker and Duchenne muscular dystrophies, (BMD and DMD) lack neuronal nitric oxide synthase (nNOS). nNOS mediates physiological sympatholysis, thus ensuring adequate blood supply to working muscle.

Duchenne and Becker muscular dystrophy (DBMD) are allelic disorders caused by mutations in dystrophin. Adults with DBMD develop life-threatening cardiomyopathy.