Duchenne trial for PTC124

Tue, 13 May 2008 21:11:50 GMT

Dear Friends of PTC,

PTC Therapeutics would like to provide an update on our recently opened clinical trial in Duchenne/Becker muscular dystrophy (DMD/BMD) of our investigational new drug PTC124.

PTC124 targets a genetic change known as a nonsense mutation. A nonsense mutation causes a genetic disorder by prematurely stopping the production of a critical protein. PTC124 may have the potential to treat genetic disorders in patients for whom a nonsense mutation is the basis for the disease, as it is in some cases of Duchenne/Becker muscular dystrophy (DMD/BMD) and cystic fibrosis (CF).

Over the past two years PTC Therapeutics has completed short-term clinical trials of PTC124 in DMD and CF; a summary of the results of these trials is available on our website (http://www.ptcbio.com/ptc124_summary). PTC has now initiated a longer-term clinical study of PTC124 in patients with DMD/BMD in which the production of the dystrophin (muscle protein) is prematurely stopped. The main goals of this study are to determine whether PTC124 can improve walking, activity, muscle function, and strength and whether the drug can safely be given over a period of many months. This study is also intended to generate the information required to support PTC124 approval by the regulatory authorities so it can be made more broadly available.

The study will be conducted in 11 countries on 4 continents. To be considered for this study, patients must have had a DNA blood test to evaluate the dystrophin gene and know that a nonsense mutation is the basis for their DMD/BMD. This test is known as genotyping or full-length gene-sequencing. Facilities that perform gene-sequencing can be located through the Gene Tests website (www.genetests.org); click “Laboratory Directory” to search for the locations of gene-sequencing facilities using the search term “dystrophinopathies.” In addition to having a nonsense mutation, study participants must be at least 5 years of age and be able to walk at least 75 meters (80 yards) unassisted in a 6-minute time period.

They must also have exhibited evidence of DMD/BMD based on the medically documented onset of characteristic clinical symptoms or signs (ie, muscle weakness, waddling gait, Gowers' maneuver) by 9 years of age, an elevated creatine kinase level in the blood, and ongoing difficulty with walking. Other inclusion criteria will be explained prior to trial enrollment. Study participants will be randomly assigned to receive either a higher dose of PTC124, a lower dose of PTC124, or a placebo (an inactive drug powder that looks and tastes the same as PTC124). The trial will be double blind, meaning that neither the researcher nor the patient will know which treatment the patient has been assigned. Several of the approximately 38 study sites for the trial have already opened and all but a few of the rest are expected to open in May or June, with the remaining ones to follow shortly thereafter. All of the planned sites are listed on www.clinicaltrials.gov (search on PTC124) and on our website (www.ptcbio.com/PTC124_clinical_trial_locations).

As soon as sites are open, contact details will be posted and participants or their families can contact a site directly to inquire about study participation. Personnel at the site will explain the study procedures and the potential benefits and risks associated with participation. Potential participants will be given an informed consent form further explaining the trial; once they have signed the form, they will be screened and considered for enrollment. Please visit www.clinicaltrials.gov for a list of sites and more information about inclusion/exclusion criteria for the trial and or our website (www.ptcbio.com/ptc124_clinical_trials) for a map of trial sites and answers to frequently asked questions about the trial. A study of PTC124 in people with cystic fibrosis due to a nonsense mutation and a DMD Phase 2a extension study are being planned to start over the coming months.

Depending upon the progress of the program, we hope to conduct clinical studies in additional nonsense-mutation-mediated genetic disorders in the future. Our patient advocacy team is happy to answer any questions you may have. Please contact us at patientinfo@ptcbio.com. Best regards, Diane Goetz

Director of Patient and Professional Advocacy

Blog: Diane Goetz Blog

Duchenne trial for PTC124