zeleciment rostudirsen (z-rostudirsen (DYNE-251)) - (DELIVER)

July 20, 2026: Dyne Therapeutics, Inc. (NASDAQ: DYN) said the FDA accepted its Biologics License Application (BLA) for zeleciment rostudirsen (z-rostudirsen; DYNE-251) to treat Duchenne muscular dystrophy (DMD) patients amenable to exon 51 skipping. The FDA granted Priority Review and set a PDUFA target action date of January 21, 2027. The company noted it is pursuing Accelerated Approval based on dystrophin as a surrogate endpoint and expects a potential U.S. launch in Q1 2027 if approved on the anticipated timeline.

The BLA is supported by the registrational expansion cohort of the global Phase 1/2 DELIVER trial, which met its primary endpoint; Dyne reports a statistically significant increase in dystrophin production with functional improvement across multiple clinical endpoints and a favorable safety profile (safety data as of Aug. 19, 2025). Z-rostudirsen continues in the DELIVER long-term extension and the global confirmatory Phase 3 FORZETTO trial.

Dyne also cited additional DMD exon-skipping candidates in development: DYNE-253 (exon 53), DYNE-245 (exon 45), DYNE-244 (exon 44), and DYNE-255 (exon 55).