The study is an open-label, single-group, multi-center extension study in patients with DMD receiving glucocorticoid steroids who participated in the SIDEROS study and who meet all the inclusion criteria and none of the exclusion criteria for this extension study.
The study consists of 4 study visits scheduled every 6 months (Visit 1/Baseline, Visit 2/Week 26, Visit 3/ Week 52 and Visit 4/ Week 78), and a follow-up visit 4 weeks after treatment discontinuation. Visit 8/Week 78 in SIDEROS study is also SIDEROS-E Visit 1/Baseline.