Dyne Therapeutics, Inc., a clinical-stage company focused on advancing life-transforming therapeutics for people living with genetically driven neuromuscular diseases, announced new long-term clinical data from its ongoing Phase 1/2 DELIVER trial of DYNE-251 demonstrating unprecedented and sustained functional improvement at the selected registrational dose of 20 mg/kg Q4W (approximate PMO dose). The DELIVER trial is evaluating DYNE-251 in individuals with Duchenne muscular dystrophy (DMD) who are amenable to exon 51 skipping, and updated results from the trial are being presented this week at the 2025 Muscular Dystrophy Association (MDA) Clinical & Scientific Conference.

“With Dyne-251, we have the opportunity to deliver a durable and redosable therapy demonstrating clinically meaningful and sustained functional improvement in DMD. The consistency of these new data across multiple endpoints and timepoints underscores the potential of DYNE-251 to meaningfully address the significant unmet need in Duchenne despite available therapies,” said John Cox, president and chief executive officer of Dyne. “We are rapidly advancing DYNE-251 toward a readout later this year with the potential to submit for U.S. accelerated approval in early 2026 based on a well-established regulatory pathway leveraging dystrophin expression as a surrogate endpoint. If approved, we believe there is an opportunity for rapid adoption by physicians and currently treated patients, as well as those naïve to therapy.”

“I am very encouraged by these new, long-term data for DYNE-251 in the exon 51 skip amenable population and the promise of sustained functional improvement which has continued to elude the DMD community,” said Pat Furlong, founder and president of Parent Project Muscular Dystrophy. “The investment and innovation in DMD are delivering, and this is a prime example of how the accelerated approval pathway may swiftly enable a new generation of therapies that address unmet and urgent medical needs.”

"The amount of expression of near-full length dystrophin induced by DYNE-251 has not been previously seen with exon 51 skipping agents and is associated with evidence for clinical efficacy,” said Kevin Flanigan M.D., Director, Center for Gene Therapy, Abigail Wexner Research Institute at Nationwide Children’s Hospital. “I look forward to the opportunity to present new functional data and updated safety data at the 2025 MDA Clinical & Scientific Conference.”

This updated assessment of the DELIVER trial evaluating DYNE-251 includes new functional data out to 12 months from 6 patients enrolled in the 20 mg/kg Q4W cohort, and 18-month functional data from 6 patients in the 10 mg/kg Q4W cohort (these participants began transitioning to the 20 mg/kg Q4W regimen after month 6). In addition, updated safety data as of February 7, 2025, continue to demonstrate a favorable safety profile for DYNE-251.