New Drug Application Filed for Sarepta’s Eteplirsen for Duchenne Muscular Dystrophy Treatment

Patrícia Silva, PhD avatar

by Patrícia Silva, PhD |

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Sarepta Therapeutics, Inc., a biopharmaceutical company focused on the development of innovative RNA-based therapeutics, recently announced that the U.S. Food and Drug Administration (FDA) has filed the New Drug Application (NDA) for the company’s eteplirsen. A NDA is the vehicle through which drug sponsors formally propose FDA to approve a new medication for sale and marketing.

Eteplirsen was developed as a therapy for Duchenne muscular dystrophy (DMD), a rare, inherited neuromuscular disorder characterized by a rapid progressive skeletal muscle weakness caused by chronic inflammation and the degeneration of muscle cells and tissue, which can compromise locomotion and the respiratory function, leading to breathing complications. DMD has a rapid progression and affects mainly boys with an estimate of one in every 3,500 worldwide. The majority of patients require a wheelchair by the age of 12 and they often succumb to the disease in their 20s due to cardio-respiratory failure.

DMD is caused by specific mutations or deletions in one or more exons (coding units) in a gene called dystrophin, which plays an important role in muscle fiber function. Exon skipping is a therapeutic approach that has been shown to restore the expression of shorter but functional versions of the dystrophin protein, potentially improving muscle function. Eteplirsen was designed to allow the skipping of exon 51 in the dystrophin gene, which allows the repair of specific genetic mutations that affect around 13% of all DMD patients. Previous studies have shown that eteplirsen has a favorable safety and tolerability profile in DMD patients, and that it allows the restoration of dystrophin protein expression.

The FDA has now completed its filing review regarding eteplirsen and has determined that the application is ready for a substantive review. The Prescription Drug User Fee Act (PDUFA) action date is February 26, 2016 where a decision will be made on the drug’s application. Eteplirsen has been granted Priority Review status by the FDA, a definition applied to drugs that offer clinical benefit in comparison to existing therapies or in cases where no adequate therapy exists.

“We are pleased with the FDA’s acceptance of our NDA for eteplirsen, as it represents an important milestone, not only for Sarepta, but for the Duchenne community. We look forward to continuing to work closely with the FDA during the regulatory review process,” said Sarepta’s Chief Executive Officer and Chief Medical Officer Dr. Edward M. Kaye in a press release. “We believe eteplirsen has the potential to make a meaningful impact on the lives of patients amenable to skipping exon 51 and we aim to build on our experience with eteplirsen to work with the FDA to inform and potentially expedite the clinical and regulatory pathway for the follow on exons, with the goal of reaching as many patients amenable to exon skipping as possible.”