( Data Presented at 59th American Academy...)PTC Therapeutics Announces Additional Positive Interim Phase 2,Results of PTC124 in Duchenne Muscular Dystrophy,Health

BOSTON and SOUTH PLAINFIELD, N.J., May 04, 2007 /PRNewswire/ -- PTC Therapeutics, Inc. (PTC), a biopharmaceutical company focused on the discovery and development of small-molecule drugs targeting post-transcriptional control processes, today announced positive interim data from a Phase 2 clinical trial of PTC124 in patients with Duchenne muscular dystrophy (DMD) due to a nonsense mutation. The results from the first two cohorts of the three-cohort study show that treatment with PTC124 was associated with increases in muscle dystrophin expression and reductions in serum creatinine kinase values in at least 50 percent of evaluable patients. These data were presented today at the 59th American Academy of Neurology (AAN) Annual Meeting.

Patients with DMD lack dystrophin, a protein that is critical to the structural stability of muscle fibers. This Phase 2 multi-site, open-label, dose-ranging clinical trial is evaluating muscle dystrophin expression in patients with nonsense-mutation-mediated DMD. Blood levels of muscle-derived creatine kinase are being measured as assessments of muscle integrity. PTC124 safety, compliance, and pharmacokinetics are also being evaluated.

"These data provide clinical evidence that PTC124 treatment may address the underlying cause of DMD," said Dr. Richard Finkel, Director of the Neuromuscular Program, Children's Hospital of Philadelphia, PA, who presented these results today at AAN as one of the trial's lead investigators. "Development of PTC124 offers the potential for a new therapeutic option for patients with DMD due to a nonsense mutation."

Langdon Miller, M.D., Chief Medical Officer of PTC, added, "We are very pleased with these additional pharmacologic proof-of-concept data from our short-term Phase 2 clinical trial of PTC124 in patients with DMD. Based on the growing body of Phase 2 clinic
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