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

Condition studied

Myotonic Dystrophy Type 1

Investigational medicinal product(s)

Eligibility

Primary endpoint

5×STS time, change from baseline at Week 49

Endpoint detail

Change from baseline at Week 49 in: vHOT; middle finger QMT total CGI-C 10-MWRT velocity (m/s) PGI-C DM1-ACTIVC total score MDHI total PGI-S CGI-S 9-HPT MDHI subscale, Maximum observed drug concentration (Cmax) Time to maximum concentration (tmax) Area under the concentration-time curve (AUC) from hour 0 to the last measurable concentration (AUCtlast) AUC extrapolated to infinity (AUC∞) Apparent terminal elimination rate constant (λZ) Apparent terminal elimination half-life (t½) Plasma clearance (CL) Volume of distribution at the terminal phase (Vz), if appropriate Volume of distribution at steady state (Vss), if appropriate, Incidence of anti-drug antibodies (ADAs), * Treatment-emergent adverse events (TEAEs) including: - Treatment-emergent serious adverse events (SAEs) - TEAEs considered related to study drug - TEAEs leading to discontinuation from study drug and discontinuation from the study * Other clinically significant safety and tolerability observations including: - Vital sign findings - 12-lead electrocardiogram (ECG) findings -Clinical laboratory values *C-SSRS results