Healthcare Industry News: PTC Therapeutics
News Release - October 21, 2006
PTC Therapeutics Announces Encouraging Preliminary Phase 2 Results of PTC124 in Duchenne Muscular DystrophySOUTH PLAINFIELD, N.J., Oct. 21 (HSMN NewsFeed) -- PTC Therapeutics, Inc. (PTC), a biopharmaceutical company focused on the discovery and development of small-molecule drugs targeting post-transcriptional control processes, today announced encouraging data from a Phase 2 clinical trial of PTC124 in patients with Duchenne muscular dystrophy (DMD) due to a nonsense mutation. The results imply pharmacological activity based on preliminary data that suggest increases in dystrophin in muscle biopsies in a number of patients and statistically significant improvements in muscle enzymes in serum. The preliminary data were presented today at the PPUK 4th International DMD Conference in London, England.
"These results are the first example of an oral therapy addressing the underlying cause of DMD by restoring dystrophin production," said Dr. Richard Finkel, Director of the Neuromuscular Program, Children's Hospital of Philadelphia, PA, one of the trial's lead investigators. "There are limited therapeutic options for patients living with DMD, and these data strongly indicate PTC124 warrants further clinical investigation in this patient population, which has a great unmet medical need."
Langdon Miller, M.D., Chief Medical Officer, PTC, stated, "These preliminary results in patients with DMD provide confirmation of proof of concept that PTC124 can induce ribosomal readthrough of nonsense mutations as an approach to treating genetic disorders. Given that PTC124 was very well- tolerated and activity was observed at lower-than-expected plasma concentrations, we are amending this trial to evaluate higher dose levels and the potential to further increase dystrophin expression."
"In the first half of 2007, we expect to present the final data set from this Phase 2 clinical trial and meet with regulatory authorities to determine the next steps for further clinical development of PTC124. Following these discussions, we hope to initiate longer-term clinical trials for PTC124 in 2007," said Dr. Miller.
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.
Patients included in the interim analysis were enrolled at three clinical sites in the United States: Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; and the University of Utah, Salt Lake City, Utah. In the study, patients received 28 days of PTC124 treatment at one of two dose levels. All patients were boys with a nonsense mutation in the dystrophin gene, substantially elevated serum creatine kinase, and symptoms associated with DMD.
Assessment of the in vitro effects of PTC124 on dystrophin expression showed dose-dependent production of full-length dystrophin in myocytes obtained from multiple study subjects; these data suggest the potential for response across a range of early to late nonsense mutations within the dystrophin gene. Evaluation of the in vivo effects of PTC124 over the 28-day treatment course suggest an increase in dystrophin expression in muscle biopsies in a number of the boys participating in the trial, although quantitative analysis is not yet complete. Statistically significant reductions in the concentrations of muscle-derived creatine kinase levels in the blood were observed during PTC124 treatment. Although no formal questionnaire was used to collect data on changes in DMD-related symptoms, several parents and teachers reported that boys participating in the study had improvements in terms of greater activity level and increased endurance during treatment.
PTC124 was well tolerated among the 26 patients included in the study. Potentially drug-related adverse events were infrequent, mild to moderate in severity, did not result in therapy interruptions or discontinuations, and were reversible. There were no safety concerns based on physical examinations, vital sign measurements, electrocardiograms, or laboratory parameters. Compliance was excellent at both dose levels.
"These preliminary results are very encouraging and add to the growing body of clinical evidence supporting the potential of PTC124 as a treatment for genetic disorders due to a nonsense mutation," said Stuart W. Peltz, Ph.D., President and Chief Executive Officer of PTC Therapeutics. "The findings in the DMD trials are consistent with the results observed in Phase 2 clinical trials of PTC124 in patients with cystic fibrosis. We intend to extend this concept into other nonsense-mediated genetic disorders."
About Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a progressive muscle disorder that causes the loss of both muscle function and independence. DMD is perhaps the most prevalent of the muscular dystrophies and is the most common lethal genetic disorder diagnosed during childhood today. Each year, approximately 20,000 children worldwide are born with DMD (one of every 3,500 male children). More information regarding DMD is available through the Muscular Dystrophy Association (http://www.mdausa.org) and the Parent Project Muscular Dystrophy (http://www.parentprojectmd.org).
PTC124 is an orally delivered product candidate in Phase 2 clinical development for the treatment of genetic disorders due to nonsense mutations. Nonsense mutations are single-point alterations in the genetic code that prematurely halt the translation process, producing a shortened, non- functional protein. PTC124 has demonstrated activity in preclinical genetic disease models harboring nonsense mutations allowing the restoration of the production of full-length, functional proteins. In Phase 1 clinical trials, PTC124 was generally well tolerated, achieved target plasma concentrations that have been associated with activity in preclinical models, and did not induce ribosomal readthrough of normal stop codons. PTC is currently conducting Phase 2 clinical trials of PTC124 in nonsense-mutation-mediated cystic fibrosis (CF) and Duchenne muscular dystrophy (DMD).
It is estimated that 10% of the cases of CF and 13% of the cases of DMD are due to nonsense mutations. PTC believes that PTC124 is potentially applicable to a broad range of other genetic disorders in which a nonsense mutation is the cause of the disease. The FDA has granted PTC124 Fast-Track designations and Orphan Drug designations for the treatment of CF and DMD due to nonsense mutations. PTC124 has also been granted orphan drug status for the treatment of CF and DMD by the Committee for Orphan Medicinal Products (COMP) of the European Medicines Agency (EMEA). PTC124's development is supported by grants from the Muscular Dystrophy Association (MDA), Cystic Fibrosis Foundation Therapeutics, Inc. (CFFT), Parent Project Muscular Dystrophy (PPMD), FDA's Office of Orphan Products Development (OOPD), and by General Clinical Research Center grants from the National Center for Research Resources (NCRR).
About PTC Therapeutics, Inc.
PTC is a biopharmaceutical company focused on the discovery and development of orally administered, proprietary small-molecule drugs that target post-transcriptional control processes. Post-transcriptional control processes regulate the rate and timing of protein production and are of central importance to proper cellular function. PTC has assembled proprietary technologies and extensive knowledge of post-transcriptional control processes that it applies in its drug discovery and development activities. PTC's current pipeline of clinical and preclinical product candidates addresses multiple indications, including genetic disorders, oncology, and infectious diseases.
Source: PTC Therapeutics
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