DMD: Sarepta Updates Community on Eteplirsen, Other Compounds
Sarepta Therapeutics updated the Duchenne MD community on regulatory and clinical trial progress with respect to eteplirsen, SRP-053 and SRP-045 on Aug. 7, 2014
Sarepta Therapeutics is on track to submit a new drug application for eteplirsen to treat a subset of patients with Duchenne musular dystrophy to the U.S. Food and Drug Administration by the end of 2014.
A confirmatory trial of eteplirsen in 60-80 boys with DMD ages 7-16 is being planned, as are trials of this drug in boys and young men with limited walking ability who are up to age 21 and in 4- to 6-year-old boys with DMD.
Sarepta is planning to test two other experimental DMD compounds – SRP-4053 and SRP-4045 – in patients with DMD in the near future.
Sarepta is the developer of eteplirsen and other compounds that target specific sections (“exons”) in the gene for the dystrophin protein in DMD patients. The goal of these compounds is to cause “exon skipping,” a process that allows cells to reinterpret genetic instructions, causing shortened, but functional, dystrophin protein to be produced.
Eteplirsen targets a section of the dystrophin gene known as exon 51 and is in the extension stage of a phase 2b clinical trial in boys with DMD who have mutations near this part of the gene. Sarepta is also developing SRP-4053, targeting exon 53 of the dystrophin gene, and SRP-4045, targeting exon 45.
MDA has been involved in the development of exon skipping as a strategy for DMD since the 1990s and has helped support the clinical testing of eteplirsen.
Status of eteplirsen, other Sarepta drugs in August 2014
Here are some key points from the Aug. 7 updates.
Regarding regulatory progress, Sarepta said the following:
It is on track to submit a new drug application (NDA) for eteplirsen to the U.S. Food and Drug Administration (FDA) by the end of 2014. (It is not yet known whether the FDA will approve eteplirsen on an “accelerated” basis or not. An accelerated approval would mean patients could have access to the drug prior to the completion of a confirmatory trial. A regular approval pathway would require the completion of a confirmatory trial prior to allowing patients to have the drug.)
The company plans to have its first meeting with the EMA later in 2014 to discuss the possibility of a special type of approval for eteplirsen in the European Union. (This would allow patients to have access to the drug prior to the completion of a confirmatory trial.)
It has submitted an application to the FDA for permission to conduct a clinical trial of SRP-4045.
It plans to submit an application to the FDA for permission to conduct a clinical trial of SRP-4053 later in 2014.
The company is preparing to meet with the FDA to discuss a plan to test SRP-4045 and SRP-4053 in the U.S. Feedback is expected in the fourth quarter of 2014 and a possible trial start in early 2015.
The company has submitted an application for permission to test SRP-4053 to the European Medicines Agency and hopes to start a clinical trial of this drug in the European Union in the coming months.
Regarding clinical trial progress, Sarepta said the following:
The company continues to be encouraged by almost three years (144 weeks) of data from its phase 2b clinical trial of eteplirsen in 12 boys with DMD in the U.S. Results on the six-minute walk test (distance a person can walk in six minutes) showed an average decline in walking distance that was slower than would be expected from the known natural history of DMD. Pulmonary function tests in this trial have shown stabilization of respiratory muscle function, and the drug continues to appear safe and well tolerated.
A confirmatory trial of eteplirsen in 60-80 boys with DMD who are ages 7-16, have mutations near exon 51 of the dystrophin gene, and meet other study criteria is being planned. The final study design (“protocol”) was reviewed by the FDA in early June. Some 40 U.S. sites are anticipated.
A trial of eteplirsen in boys and young men with DMD with limited walking ability is expected to open about November 2014. It will evaluate participants on the basis of pulmonary function tests and other measures and will include about 20 patients in the U.S. who are up to age 21.
A plan for a trial of eterplirsen in about 20 U.S. patients with DMD who are 4-6 years old is on track for submission to the FDA.
A trial of SRP-4053 in boys with DMD who are 6-15 years old, able to walk a minimum distance, and have mutations near exon 53 is expected to start in September 2014 in about 24 participants in the United Kingdom, France and Italy.