A Study to Assess the Efficacy and Safety of Satralizumab in Duchenne Muscular Dystrophy (DMD)

Participants will be included in two groups: ambulatory participants with fractures and non-ambulatory participants with or without a history of fractures (Group 1) and ambulatory participants who are fracture-naïve (Group 2) at baseline. The study will assess the potential of satralizumab to improve bone fragility and to increase muscle function. A weight-tier-based dose of satralizumab will be given by subcutaneous (SC) injection every 4 weeks (Q4W).