The exon-skipping drug was approved by the FDA for DMD patients with mutations in the dystrophin gene amenable to exon 53 skipping, a group that accounts for around 8% of the total DMD population.

Of note, exon-skipping oligonucleotides and gene therapy in DMD have been approved under the FDA's accelerated approval program, using a surrogate marker instead of clinical benefit as an endpoint.

Sarepta's exon-skipping therapies for DMD – Exondys 51, Vyondys 53 (golodirsen), and Amondys 45 (casimersen) – have been the main drivers of Sarepta's revenue growth in recent years ...