Duchenne muscular dystrophy (DMD) is a progressive, fatal neuromuscular disease characterized by the loss of muscle function beginning in early childhood. On average, patients experience declining ambulatory function until losing the ability to walk by early teens. Evaluation of ambulatory function is typically performed in the clinic using the 6MWT and NSAA, but these tools are prone to bias and variability that can make interpretation of longitudinal changes difficult. Stride velocity 95th centile (SV95C), which represents the fastest spontaneous strides in a patient’s daily life as captured by a wearable device, is an objective assessment of peak performance accepted as a qualified secondary endpoint for DMD patients 5 years and older by the EMA and is currently evaluated in several clinical trials.
In the Phase 1/2 study IGNITE DMD, nine subjects were treated with SGT-001 microdystrophin gene therapy, with the first 3 receiving 5E13vg/kg and the next 6 administered 2E14vg/kg. Three untreated subjects were also enrolled in the study and analyzed as controls. SV95C was analyzed for all ambulatory subjects aged 5 and older at baseline. Control subjects showed diminished SV95C at all post-baseline timepoints up to 1 year, similar to natural history. SGT-001 treated subjects showed an average improvement in SV95C at all post-treatment timepoints, with positive results observed in both dose groups. Together with previously presented data, these results provide additional evidence that patients treated with SGT-001 microdystrophin gene therapy may be experiencing a benefit to motor function and a clinical course that diverges from untreated patients.