– Casimersen is designed for the treatment of exon 45 amenable patients, approximately eight percent of patients with Duchenne —

— Casimersen is the third exon-skipping medicine using the Company’s proprietary PMO RNA-based platform — 

CAMBRIDGE, MA, USA I June 26, 2020 I Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today announced the Company has completed the submission of a rolling New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) seeking accelerated approval for casimersen (SRP-4045). Casimersen, a phosphorodiamidate morpholino oligomer (PMO), is engineered to treat patients with Duchenne muscular dystrophy (DMD) who have genetic mutations that are amenable to skipping exon 45 of the Duchenne gene.

The completion of the rolling submission includes data from the casimersen arm of the ESSENCE study (also known as study 4045-301), a global, randomized, double-blind, placebo-controlled Phase 3 study evaluating efficacy and safety in patients amenable to skipping exons 45 and 53. An interim analysis from ESSENCE demonstrated a statistically significant increase in dystrophin production as measured by western blot in patients who received casimersen compared to baseline and placebo. The study is ongoing, and remains blinded to collect additional efficacy and safety data. If the casimersen NDA is accepted and granted accelerated approval, the completed ESSENCE study will serve as a post-marketing confirmatory study.

“The completion of our casimersen submission is an important milestone in our journey to advance treatments for the greatest possible number of people living with Duchenne muscular dystrophy,” said Doug Ingram, president and chief executive officer, Sarepta Therapeutics. “If approved, casimersen will be our third approved therapy for sub-populations of Duchenne. Together with our other approved therapies, we have the potential to treat nearly 30% of Duchenne patients in the United States. Our proprietary PMO platform is an important focus of our pipeline, and we owe our clinical progress to the patients and families participating in our studies.”

About Casimersen

Casimersen uses Sarepta’s proprietary phosphorodiamidate morpholino oligomer (PMO) chemistry and exon-skipping technology to skip exon 45 of the DMD gene. Casimersen is designed to bind to exon 45 of dystrophin pre-mRNA, resulting in exclusion, or “skipping,” of this exon during mRNA processing in patients with genetic mutations that are amenable to exon 45 skipping. Exon skipping is intended to allow for production of an internally truncated dystrophin protein.

About Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a rare, fatal neuromuscular genetic disease that occurs in approximately one in every 3,500-5,000 males worldwide. DMD is caused by a change or mutation in the gene that encodes instructions for dystrophin. Symptoms of DMD usually appear in infants and toddlers. Affected children may experience developmental delays such as difficulty in walking, climbing stairs or standing from a sitting position. As the disease progresses, muscle weakness in the lower limbs spreads to the arms, neck and other areas. Most patients require full-time use of a wheelchair in their early teens, and then progressively lose the ability to independently perform activities of daily living such as using the restroom, bathing and feeding. 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 patients usually succumb to the disease in their twenties.

About Sarepta Therapeutics
At Sarepta, we are leading a revolution in precision genetic medicine and every day is an opportunity to change the lives of people living with rare disease. The Company has built an impressive position in Duchenne muscular dystrophy (DMD) and in gene therapies for limb-girdle muscular dystrophies (LGMDs), mucopolysaccharidosis type IIIA, Charcot-Marie-Tooth (CMT), and other CNS-related disorders, with more than 40 programs in various stages of development. The Company’s programs and research focus span several therapeutic modalities, including RNA, gene therapy and gene editing. For more information, please visit www.sarepta.com or follow us on Twitter, LinkedIn, Instagram and Facebook.

SOURCE: Sarepta Therapeutics