Dyne Therapeutics has announced FDA Breakthrough Therapy Designation for DYNE-251 in Duchenne Muscular Dystrophy. This designation reflects encouraging early results from the DELIVER clinical trial, where patients demonstrated sustained functional improvements, such as faster time to rise and improved walking speed over an 18-month period.
DYNE-251 is designed to enable the production of near full-length dystrophin, a key protein for muscle function. Full data from the Phase 1/ 2 registrational expansion cohort of the DELIVER trial is expected in late 2025, and Dyne plans to submit a Biologics License Application (BLA) for U.S. accelerated approval in early 2026. Dyne is also pursuing international regulatory pathways and expanding its Duchenne pipeline with preclinical programs targeting other exons, including 53, 45, and 44. While these developments are promising, Dyne cautions that outcomes depend on continued clinical success and regulatory review.
Breakthrough Therapy designation is utilized by the FDA to help speed the development and review of treatments for serious conditions like Duchenne. It’s granted when early clinical data suggests that a therapy may offer meaningful improvement over existing options on key measures of effectiveness. The designation may allow for a shortened FDA review process, potentially reducing it from 12 to 8 months.
PPMD is pleased to see Dyne recognized with Breakthrough Therapy designation and encouraged by the progress of DYNE-251. We are optimistic about what this may mean for the community and look forward to continued updates from Dyne in the months ahead. This designation underscores the potential of DYNE-251 to address the critical needs of individuals living with Duchenne, particularly those with exon 51 amenable mutations. We are grateful for Dyne’s commitment to the community and to developing innovative therapies, and we remain hopeful that this momentum will translate into meaningful clinical benefit for individuals and families impacted by Duchenne.
Read Dyne’s press release here.
Read Dyne’s community letter:
August 4, 2025
To the Duchenne Muscular Dystrophy Community:
We recognize and share the sense of urgency in the community and are inspired every day by the strength of individuals, families and caregivers. This is what drives our work to advance potential therapies designed to deliver functional improvement for people living with Duchenne muscular dystrophy (DMD).
Today, we are pleased to share that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to DYNE-251, our investigational therapy for the treatment of patients with DMD, amenable to exon 51 skipping.
The FDA grants Breakthrough Therapy Designation to therapies that show early promise of being significantly better than current treatments, especially in improving meaningful outcomes for patients. This special FDA designation means we’ll receive added support from senior FDA experts and have early, frequent communication with them to help guide our development and regulatory strategy more efficiently and effectively.
While DYNE-251 remains investigational and has not yet been approved by the FDA or other regulatory agencies, this designation affirms our belief in its potential and further energizes our team to continue to work with focus, care and urgency.
We remain grateful to the entire patient community for your trust and engagement. Participation in the DELIVER clinical trial generated the data that supports this designation and helps progress this program forward.
Looking ahead, we plan to deliver data from the ongoing Registrational Expansion Cohort of the DELIVER clinical trial in late 2025, and expect these data, as well as results from previous parts of the trial, to support a potential submission for Accelerated Approval in the United States in early 2026.
We invite you to read our full press release here and encourage you to reach out to your healthcare provider if you have questions about the DELIVER trial or DYNE-251.
With gratitude and hope,
The Dyne Therapeutics Team
The post Dyne Therapeutics, Inc. announced today FDA Breakthrough Therapy Designation for DYNE-251 in Duchenne Muscular Dystrophy appeared first on Parent Project Muscular Dystrophy.