The Food and Drug Administration’s (FDA’s) Division of Neurology has accepted its New Drug Application (NDA) seeking accelerated approval for golodirsen (SRP-4053) and provided a regulatory action date of August 19, 2019. Golodirsen is a phosphordiamidate morpholino oligomer engineered to treat those individuals with Duchenne muscular dystrophy (Duchenne) who have genetic mutations subject to skipping exon 53 of the dystrophin gene. Duchenne is a fatal genetic neuromuscular disorder affecting an estimated one in approximately every 3,500 – 5,000 males born worldwide.
The company completed its NDA at the end of 2018 as part of a rolling submission and requested priority review, which was granted. The company previously received orphan drug designation for golodirsen. The NDA includes data from the 4053-101 study assessing the safety, tolerability, pharmacokinetics and dystrophin expression of golodirsen in 25 boys with confirmed deletions of the dystrophin gene amenable to exon 53 skipping. The study demonstrated statistically significant results in favor of golodirsen on all biological endpoints, including properly exon-skipped RNA transcript using reverse transcription polymerase chain reaction, increase in quantity of dystrophin expression from baseline using Western blot and increase in dystrophin intensity as measured by immunohistochemistry.
“If approved, golodirsen will serve up to another 8 percent of the Duchenne community, bringing us closer to helping as many Duchenne patients as possible,” said Doug Ingram, president and chief executive officer, Sarepta. “We look forward to working with the FDA toward advancing this important therapy and rapidly bringing it to individuals with Duchenne who are amenable to exon 53 skipping.”
Golodirsen is also being studied in Sarepta’s ongoing ESSENCE study (4045-301), a global, randomized double-blind, placebo-controlled study assessing the safety and efficacy of golodirsen and casimersen, our exon 45 skipping agent. The Division has previously confirmed that the ESSENCE study could possibly serve as a post-marketing confirmatory study.
Golodirsen uses Sarepta’s proprietary phosphorodiamidate morpholino oligomer (PMO) chemistry and exon-skipping technology to skip exon 53 of the DMD gene. Golodirsen is designed to bind to exon 53 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 53 skipping. Exon skipping is intended to allow for production of an internally truncated but functional dystrophin protein.