Becker Muscular Dystrophy: Could Altering the Natural History of Decline Help Tackle Unmet Medical Need?

This symposium was held as part of the 28th International Annual Congress of the World Muscle Society (WMS), held in Charleston, South Carolina, USA. Speakers reviewed the natural history of Becker muscular dystrophy (Becker), outlined the top line, 12-month data from the ARCH open label study of investigational agent EDG-5506, and aimed to put those results into clinical context. Becker is a serious rare disease with significant physical, emotional, financial, and social impact on the affected individuals and their caregivers. Once function begins to decline, males affected by the progressive X-linked genetic disorder continue to irreversibly lose muscle, ultimately leading to the loss of ambulatory and cardiopulmonary function. After discussing the aetiology of the condition, Erik Niks, Paediatric and Adult Neurologist, Leiden University Medical Center (LUMC), the Netherlands, presented the findings of natural history studies. They showed that while the age at which decline begins varies, once it does start, patients tend to experience a consistent decline in function equivalent to around 1.2–1.3 North Star Ambulatory Assessment (NSAA) points each year. This finding, combined with data on using MRI as a biomarker of disease progression, provides an evidence-based framework for clinical trial design, he argued. Sam Collins, Vice President of clinical development, Edgewise Therapeutics, Boulder, Colorado, USA, then presented topline 12-month data from the ARCH study. It found that EDG-5506 was well tolerated, and, importantly, recorded the stabilisation of functional assessments, including the NSAA, with a trend towards improvement, as well as rapid, sustained, and significant decreases in biomarkers of progression, including those related to muscle damage. Putting the ARCH study data into context, Barry Byrne, Director of the Health Center for Advanced Therapeutics and Powell Gene Therapy Center, University of Florida (UF), Gainesville, USA, explained exactly how declining NSAA status translated into life-altering function loss. Stabilising function, or even reducing the speed of decline, was an important goal for patients, he said, adding that meeting it could help to address significant unmet medical need.