A Phase 3, Randomized, Double-Blind, 48-Week Placebo-Controlled Study to Assess the Efficacy, Safety, and Tolerability of DYNE-101 Administered to Participants With Myotonic Dystrophy Type 1

The study consists of three periods: a Screening period (up to 8 weeks), Placebo-Controlled Period (48 weeks) and a Long-Term Extension Period (24 weeks). An Independent Data Monitoring Committee (IDMC) comprised of members independent and external to the Sponsor will review safety and tolerability data of this study at regular intervals.