DYNE-302

July 28, 2026: Dyne Therapeutics, Inc. (NASDAQ: DYN) said the FDA cleared its IND to begin a Phase 1 clinical trial of DYNE-302 for facioscapulohumeral muscular dystrophy (FSHD), marking the company’s third clinical program leveraging its FORCE™ platform. DYNE-302 uses a TfR1-targeting Fab to deliver an siRNA payload designed to suppress DUX4 mRNA, aiming to reduce DUX4-driven pathology in skeletal muscle.

Preclinical FSHD models showed robust knockdown of the DUX4 transcriptome in skeletal muscle, significant reversal of muscle fiber damage, and functional improvement in a severe disease model.

The planned Phase 1 study is a randomized, placebo-controlled, double-blind, multiple ascending dose trial in ambulatory adults with FSHD. Primary endpoint is safety/tolerability, with PK/PD assessments including changes in muscle DUX4 transcriptome and plasma KHDC1L (identified by Dyne as a DUX4-regulated biomarker). The first cohort (n=9) will receive three IV doses every four weeks (Q4W), randomized 2:1 to DYNE-302 1.5 mg/kg (approximate siRNA dose) or placebo, with plans to evaluate higher doses and less frequent dosing thereafter. Participants may enter an open-label extension for up to 96 additional weeks. Dyne intends to pursue a traditional U.S. approval pathway for DYNE-302.