There is encouraging news for the Duchenne community as Dyne Therapeutics has announced positive top-line results from their ongoing DELIVER clinical trial. The data highlights significant progress for zeleciment rostudirsen (also known as z-rostudirsen or DYNE-251), an investigational treatment for individuals with Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping.
The announcement covers results from the Registrational Expansion Cohort (REC) of the trial, alongside new long-term data showing that the benefits of the treatment have been sustained over 24 months.
About the DELIVER Trial
The DELIVER trial is a global, randomized, placebo-controlled Phase 1/2 study designed to evaluate the safety, tolerability, and efficacy of z-rostudirsen. The trial is divided into two main parts:
- Part 1 (MAD): A Multiple Ascending Dose study involving a small number of participants to determine the appropriate dose.
- Part 2 (REC): The Registrational Expansion Cohort, which tested the selected dose in a larger group to evaluate safety and efficacy.
Participants who completed MAD and REC are now continuing to receive the treatment as part of an open-label extension.
Key Highlights from the Results
Dyne Therapeutics reported positive outcomes in three critical areas: dystrophin expression, functional ability, and long-term sustainability.
1. Significant Increase in Dystrophin in the Registrational Expansion Cohort (REC), with the trial meeting its primary endpoint. Participants showed a statistically significant increase in dystrophin protein expression.
2. Functional Improvements Across the Board beyond the biological markers, the trial measured functional outcomes that impact daily life. In the cohort of 32 participants, improvements relative to placebo were observed across all six prespecified endpoints at the six-month mark. These six endpoints covered upper limb function, lower limb function as well as Lung function.
3. Sustained Long-Term Benefits New long-term data from the earlier MAD cohort provided a look at how the treatment performs over time. Encouragingly, the functional improvements seen at earlier stages were sustained through 18 and 24 months across the same six endpoints.
Safety and Tolerability Profile
Safety data collected from participants followed for up to 36 months continues to show a favorable profile for z-rostudirsen. According to Dyne, most “treatment-emergent adverse events” (TEAEs) were mild or moderate.
In the Registrational Expansion Cohort specifically, there were no related serious adverse events. However, in the open-label portion of the trial, two participants experienced serious events related to the treatment (malaise and/or fever). Dyne reports that both participants fully recovered and have continued to receive z-rostudirsen without interruption.
Looking Ahead: Timeline for Approval
With these positive results in hand, Dyne has outlined a clear path toward potential regulatory approval and availability:
- Q2 2026: Dyne plans to submit a Biologics License Application (BLA) for U.S. Accelerated Approval.
- Q2 2026: Initiation of a global Phase 3 clinical trial to support approvals worldwide.
- Q1 2027: Potential launch in the U.S. (assuming the FDA grants Priority Review).
Dyne also confirmed they are actively pursuing approval pathways outside of the U.S. to ensure access for global patients amenable to exon 51 skipping.
A Message to the Community
The team at Dyne Therapeutics shared a direct message of gratitude to Action Duchenne and the families involved in this research:
“Your insights and expertise have been vital in shaping our science and guiding the design of Dyne’s programs. We deeply appreciate the individuals and families who have devoted their time and trust to this clinical trial. Because of their unwavering commitment, we are able to move scientific understanding forward and drive progress in DMD drug development.”
