Duchenne muscular dystrophy: Drug development and regulatory considerations

Duchenne muscular dystrophy (DMD) is one of the most commonly recognized dystrophinopathies. There are no approved therapeutic options available for this disease but recent discoveries have led to hope that effective therapies might be forthcoming. With funding from patient advocacy groups, private investors, and governmental bodies such as the Food and Drug Administration Office of Orphan Product Development (FDA/OOPD), gene modification and other molecular therapies are being actively investigated. However, since DMD patients are few in number and disease manifestations vary considerably in early and late stages of disease, obtaining the data needed for full evaluation of putative therapies may prove challenging. Should ambulation remain the focus of Phase 2/3 studies or should consideration be given to the primary causes of late-stage morbidity and mortality, e.g., cardiac and respiratory dysfunction related to reduced or absent dystrophin production? It seems reasonable to argue that clinical trials planned for DMD should consider the entire population.