Dyne Therapeutics, Inc., a clinical-stage biotechnology company focused on developing therapies for genetically driven neuromuscular diseases, has announced that the U.S. Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) for zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251) for the treatment of individuals with Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping.

The FDA has granted the application Priority Review and assigned a Prescription Drug User Fee Act (PDUFA) target action date of January 21, 2027. Subject to regulatory approval, Dyne Therapeutics expects to commercially launch the therapy in the United States during the first quarter of 2027.

The BLA is supported by data from the registrational expansion cohort of the global Phase 1/2 DELIVER clinical trial, which met its primary endpoint. The investigational therapy continues to be evaluated in the long-term extension phase of the DELIVER study and the global confirmatory Phase 3 FORZETTO clinical trial.

Z-rostudirsen is designed for patients with DMD caused by mutations in the DMD gene that are amenable to exon 51 skipping. The therapy combines a phosphorodiamidate morpholino oligomer (PMO) with an antigen-binding fragment (Fab) targeting the transferrin receptor 1 (TfR1), enabling enhanced delivery to muscle tissue and the central nervous system. The approach is intended to restore production of near-full-length dystrophin, a protein essential for muscle function.

Commenting on the milestone, John Cox, President and Chief Executive Officer of Dyne Therapeutics, said the FDA's acceptance marks significant progress toward delivering meaningful functional improvement for people living with Duchenne muscular dystrophy. He added that the company is continuing commercial launch preparations to make the therapy available as quickly as possible following potential approval.

The investigational therapy has previously received Breakthrough Therapy, Fast Track, Rare Pediatric Disease, and Orphan Drug designations from the FDA, while also receiving Orphan Drug designation from the European Medicines Agency (EMA) and Japan's Ministry of Health, Labour and Welfare.

Beyond z-rostudirsen, Dyne Therapeutics is advancing a broader Duchenne muscular dystrophy pipeline, including development candidates DYNE-253, DYNE-245, DYNE-244, and DYNE-255, targeting patients with mutations amenable to exon skipping of exons 53, 45, 44 and 55, respectively.

Duchenne muscular dystrophy is a rare, progressive genetic disorder caused by mutations in the DMD gene, resulting in the absence of dystrophin and progressive muscle degeneration. Despite currently available therapies, significant unmet medical needs remain, highlighting the importance of innovative treatment approaches aimed at improving long-term functional outcomes for patients.