PCT124 yields promising animal data in DMD

New preclinical data published in the on-line April edition of the journal Nature show that PTC124, an Investigational New Drug designed to bypass nonsense mutations, was efficacious in a preclinical model of Duchenne muscular dystrophy. 13% of the cases of DMD are due to nonsense mutations and the results have led to hopes that the agent could be used to treat similar genetic disorders.

USA-based PTC Therapeutics, which discovered and is developing PTC124, has cataloged over 1,800 distinct disorders where nonsense mutations are the cause in a significant percentage of patients. This type of defect inactivates gene function and causes anywhere from 5%-70% of the individual cases of most inherited diseases, such as cystic fibrosis (10%) and Hurler's syndrome (70%).

In the mouse model of DMD used by PCT, a nonsense mutation precludes the production of dystrophin, an important muscle protein involved in the strength of muscle fibers, leading to DMD. The data demonstrate that PTC124 allows dystrophin to be made in cells in which it was previously absent, to be delivered to the proper cellular location and to induce restoration of muscle function, the firm noted. In addition, PTC has demonstrated that the agent restores the presence of the missing protein in an animal model of cystic fibrosis based on nonsense mutations.