PTC Therapeutics has initiated a Phase II study of PTC124 in patients with Duchenne muscular dystrophy (DMD) due to a nonsense mutation.

PTC124 is a novel, orally administered drug that targets nonsense mutations and is being investigated initially as a treatment for DMD and cystic fibrosis, with the potential to treat a number of other genetic disorders caused by nonsense mutations.

The primary endpoint of this multisite, open-label, dose-ranging study is assessment of muscle dystrophin expression in response to treatment with PTC124. Other assessments include the presence of dystrophin mRNA and dystrophin-related proteins, muscle function, compliance with treatment, safety, and pharmacokinetics.