Safety, Tolerability, Pharmacodynamic, Efficacy, and Pharmacokinetic Study of DYNE-101 in Participants With Myotonic Dystrophy Type 1

This study evaluates the safety and potential effectiveness of DYNE-101, an investigational intravenous drug designed to reduce the toxic RNA buildup that causes muscle disease in people with Myotonic Dystrophy Type 1 (DM1), a hereditary condition causing progressive muscle weakness and stiffness. The study includes a placebo-controlled phase followed by an open-label treatment period and a long-term extension. Adults with confirmed DM1 (trinucleotide repeat size greater than 100) who have clinically measurable myotonia (muscle stiffness), adequate grip and ankle strength, and can complete functional tests without assistive devices are eligible; those with significant cardiac conduction problems, severely reduced lung function, or a history of anaphylaxis are excluded. Participation involves receiving IV infusions of DYNE-101 or placebo every few weeks over several years, with regular safety assessments and muscle function tests. This summary was prepared using AI to help patients understand the study in plain language.