Background: Sarepta announced today that the U.S. Food and Drug Administration (FDA) has accepted its New Drug Application (NDA) for eteplirsen to treat Duchenne muscular dystrophy (DMD).

Eteplirsen is an “exon-skipping” drug that targets a section of DNA called exon 51, and may help up to 13 percent of Duchenne muscular dystrophy (DMD) patients.

Exon skipping is a treatment strategy in which sections of genetic code are “skipped,” allowing cells to manufacture partially functional dystrophin, the muscle protein missing in DMD. Exon skipping is not a cure for DMD, but potentially could lessen the severe muscle weakness and atrophy that is the hallmark of the disease.

Today’s news follows an announcement from Sarepta on Aug. 21 that the FDA has granted Rare Pediatric Disease Designation for eteplirsen. This designation supplements the Orphan Drug Designation and Fast Track Status previously granted by the FDA for this drug.

The FDA has granted eteplirsen priority review status. The date for a decision on the application is Feb. 26, 2016.

Statement from MDA Scientific Program Officer Laura Hagerty, Ph.D.:

“This is another important step forward for our Duchenne families. Now, two potential DMD treatments have had their NDAs accepted by the FDA for priority review and both companies will be hoping for a positive decision in early 2016. We’re nearing the finish line — this is as close as we’ve ever been to having approved therapies for one of the most common and debilitating forms of muscular dystrophy.

“MDA has provided support for the development of exon skipping since the 1990s and we are proud to have funded foundational research that has made these new treatments possible. It is a sign of great progress to witness multiple companies working on different therapies to get urgently-needed treatments to our families.

“MDA is committed to bringing safe and effective treatments and cures to children and adults living with life-threatening neuromuscular diseases as quickly as possible. Today, there are new treatments in the pipeline that were inconceivable just a few years ago and more potential treatments are expected during the next five years than in the past five decades. As these treatments enter the regulatory review phase, MDA continues to work hand-in-hand with families, health care professionals, scientists and the FDA to ensure it has the necessary information and support to efficiently make decisions on potential life-changing drugs and to move these treatments from the labs to our families’ living rooms.”

See below to read Sarepta’s press release:

Sarepta Therapeutics Announces FDA Has Filed Eteplirsen NDA for the Potential Treatment of Duchenne Muscular Dystrophy for Patients Amenable to Exon 51 Skipping

FDA Grants Priority Review Status

PDUFA Date is February 26, 2016

CAMBRIDGE, Mass. – (BUSINESS WIRE) – Aug. 25, 2015– Sarepta Therapeutics, Inc. (NASDAQ:SRPT), a developer of innovative RNA-targeted therapeutics, today announced that the U.S. Food and Drug Administration (FDA) has filed the New Drug Application (NDA) for eteplirsen for the treatment of Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping. Approximately 13% of people with Duchenne muscular dystrophy are estimated to have a mutation addressable by Eteplirsen/exon 51 skipping.

The FDA has completed its filing review and has determined that our application is sufficiently complete to permit a substantive review. The Prescription Drug User Fee Act (PDUFA) action date for a decision on the application is February 26, 2016. The FDA has granted eteplirsen Priority Review status, which is designated to drugs that offer benefit over existing therapies, or provide a treatment 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 Edward M. Kaye, interim chief executive officer and chief medical officer. “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.”

About Sarepta Therapeutics

Sarepta Therapeutics is a biopharmaceutical company focused on the discovery and development of unique RNA-targeted therapeutics for the treatment of rare, infectious and other diseases. The Company is primarily focused on rapidly advancing the development of its potentially disease-modifying DMD drug candidates, including its lead DMD product candidate, eteplirsen, designed to skip exon 51. Sarepta is also developing therapeutics for the treatment of infectious diseases, such as drug-resistant bacteria and other rare human diseases. For more information, please visit us at www.sarepta.com.

About Eteplirsen

Eteplirsen is Sarepta’s lead drug candidate and is designed to address the underlying cause of DMD by enabling the production of a functional dystrophin protein. Data from clinical studies of eteplirsen in DMD patients have demonstrated a broadly favorable safety and tolerability profile and restoration of dystrophin protein expression.

Eteplirsen uses Sarepta’s novel phosphorodiamidate morpholino oligomer (PMO)-based chemistry and proprietary exon-skipping technology to skip exon 51 of the dystrophin gene enabling the repair of specific genetic mutations that affect approximately 13% of the total DMD population. By skipping exon 51, eteplirsen may restore the gene’s ability to make a shorter, but still functional, form of dystrophin from messenger RNA, or mRNA. Promoting the synthesis of a truncated dystrophin protein is intended to stabilize or significantly slow the disease process and prolong and improve the quality of life for patients with DMD.

About Duchenne Muscular Dystrophy

DMD is an X-linked rare degenerative neuromuscular disorder causing severe progressive muscle loss and premature death. One of the most common fatal genetic disorders, DMD affects approximately one in every 3,500 boys born worldwide. A devastating and incurable muscle-wasting disease, DMD is associated with specific errors in the gene that codes for dystrophin, a protein that plays a key structural role in muscle fiber function. Progressive muscle weakness in the lower limbs spreads to the arms, neck and other areas. Eventually, increasing difficulty in breathing due to respiratory muscle dysfunction requires ventilation support, and cardiac dysfunction can lead to heart failure. The condition is universally fatal, and death usually occurs before the age of 30.