Skipping, Steroids, and Genes The First 7 Therapies for Duchenne Muscular Dystrophy

It took 30 years from the discovery of the gene associated with Duchenne muscular dystrophy (DMD) in 1986(1) to arrive at the first FDA approval of a therapy for this devastating disease. The publication in this issue of Neurology (R) of the 48-week data from the pivotal clinical trial for vamorolone in DMD2 helps usher in an era that would have been inconceivable even a few years ago: US FDA approvals for DMD have become a regular occurrence. In their study, Dang and colleagues show that improved motor outcomes were sustained beyond 24 weeks out to 48 weeks of treatment, that a higher dose (6 mg/kg/d) resulted in better maintenance of benefit, and that a rapid benefit occurred after crossover from prednisone to vamorolone. Vamorolone is the seventh therapy for DMD approved by the FDA since 2016; thus, these approvals have been occurring on average nearly once a year since then. There are now 2 corticosteroids, 4 antisense oligonucleotide exon skipping compounds, and an adeno-associated virus-based gene therapy available for clinical use (Table). Prednisone continues to be used off label for many affected individuals. Where does that leave our patients?