Eteplirsen Approved for Duchenne Muscular Dystrophy: The FDA Faces a Difficult Choice

Eeplirsen (Sarepta Inc., Boston, MA) is a 30-mer phosphomorpholidate oligonucleotide that has been evaluated in young male patients with the devastating disease known as Duchenne muscular dystrophy (DMD). This X-linked disease, found in approximately 1/3,500–1/5,000 live male births,1 is characterized by mutations in the dystrophin gene that take the messenger RNA (mRNA) reading frame out of frame. These mutations can produce premature stop codons1 in the dystrophin mRNA, leading to mRNA degradation and the loss of protein synthesis2,3 in striated muscle, resulting in catastrophic clinical consequences.