Sarepta Therapeutics’ (SRPT) Exondys 51 uses exon-skipping technology to skip exon 51 of the DMD gene. The drug is designed to bind to exon 51, which leads to an exclusion or skipping of this exon during mRNA processing. Golodirsen uses exon-skipping technology to skip exon 53 of the DMD gene.
Sarepta is currently enrolling and dosing patients in its Phase 3 placebo-controlled confirmatory trial, called Essence, in patients with the mutated DMD gene that is amenable to exon 45 or 53 skipping using casimersen and golodirsen.
Golodirsen is also in a Phase 1/Part 2 study, which is an open-label portion of the study. In March, Sarepta announced that it planned to submit a new drug application (or NDA) to the FDA by the end of 2018.
This NDA is related to the accelerated approval of golodirsen for treating patients with DMD who are amenable to exon 53 skipping. The drug can address one of the most prevalent sets of mutations in DMD that are amenable to exon skipping.
Casimersen and SRP-5051
Sarepta’s casimersen uses exon-skipping technology to skip exon 45 of the DMD gene. The drug is designed to bind to exon 45 of dystrophin pre-mRNA. Sarepta’s SRP-5051 is designed to bind to exon 51 of dystrophin pre-mRNA. The company expects to have data related to safety and future dosing for the drug in the second half of the year.
Sarepta is expected to incur R&D (research and development) expenses of $277.8 million in fiscal 2018, compared with $166.71 million in fiscal 2017. For fiscal 2018, its peers Alnylam Pharmaceuticals (ALNY), Alexion Pharmaceuticals (ALXN), Biogen (BIIB), and Gilead Sciences (GILD) are expected to incur R&D expenses of $464.7 million, $816.7 million, $2.48 billion, and $3.73 billion, respectively.
We’ll look at Sarepta Therapeutics’ research collaborations in the next part.