Dyne Therapeutics' DYNE-251 granted Breakthrough Therapy Designation for Duchenne Muscular Dystrophy treatment.

Dyne Therapeutics announced that the FDA has granted Breakthrough Therapy Designation to DYNE-251 for Duchenne muscular dystrophy (DMD) treatment. The designation is based on data from the ongoing DELIVER clinical trial. The company expects DELIVER registrational expansion cohort data in late 2025, with a potential BLA submission for U.S. accelerated approval anticipated in early 2026.

Dyne Therapeutics (NASDAQ: DYN) has received a significant regulatory milestone with the FDA granting Breakthrough Therapy Designation to DYNE-251 for the treatment of Duchenne muscular dystrophy (DMD). This designation is based on data from the ongoing DELIVER clinical trial, which demonstrated sustained functional improvement in key mobility measures like time to rise and stride velocity over 18 months [1].

The Breakthrough Therapy Designation accelerates the potential approval pathway for DYNE-251, offering tangible regulatory advantages such as enhanced FDA support, expedited review timelines, and eligibility for rolling submission. Dyne has completed enrollment of 32 patients in the DELIVER registrational expansion cohort, with data expected in late 2025, positioning the company for a potential Biologics License Application (BLA) submission for U.S. accelerated approval by early 2026 [1].

DYNE-251 is an investigational therapeutic being evaluated in the Phase 1/2 global DELIVER clinical trial for individuals with DMD who have mutations in the DMD gene amenable to exon 51 skipping. The drug consists of a phosphorodiamidate morpholino oligomer (PMO) conjugated to an antigen-binding fragment (Fab) that binds to the transferrin receptor 1 (TfR1), designed to enable the production of near full-length dystrophin in muscle and the central nervous system (CNS) [1].

The FDA's Breakthrough Therapy Designation for DYNE-251 marks a significant regulatory milestone for Dyne Therapeutics' DMD program. The designation requires preliminary clinical evidence indicating substantial improvement over existing therapies on clinically significant endpoints. This milestone highlights the strength of the clinical data Dyne has generated thus far, including the production of near-full-length dystrophin, which is particularly noteworthy as current exon-skipping therapies have struggled with producing sufficient dystrophin levels to deliver meaningful functional benefits [1].

For patients with DMD amenable to exon 51 skipping (approximately 13% of DMD patients), DYNE-251 could potentially offer a more effective treatment option than currently available therapies. The DELIVER trial is a global, randomized, placebo-controlled, double-blind study evaluating the safety, tolerability, and efficacy of DYNE-251 in individuals with DMD [1].

Dyne Therapeutics is focused on delivering functional improvement for people living with genetically driven neuromuscular diseases. The company is advancing clinical programs for myotonic dystrophy type 1 (DM1) and Duchenne muscular dystrophy (DMD), and preclinical programs for facioscapulohumeral muscular dystrophy (FSHD) and Pompe disease [1].

References:
[1] https://www.stocktitan.net/news/DYN/dyne-therapeutics-announces-fda-breakthrough-therapy-designation-for-0wbjhe133ddv.html