DMD and Duchenne muscular dystrophy: To date, four PMO drugs have been approved by the FDA: eteplirsen, golodirsen, viltolarsen, and casimersen (Eteplirsen targets exon 51, Golodirsen and Viltolarsen target exon 53, and Casimersen targets exon 45 of the dystrophin mRNA) for Duchenne Muscular Dystrophy [73,74] (Table 1).