Dyne Therapeutics, a clinical-stage company focused on advancing life-transforming therapeutics for people living with genetically driven neuromuscular diseases, today 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.
Key findings from the DELIVER Phase 1/2 trial presentation include:
- Function: Meaningful and sustained improvements from baseline in multiple functional endpoints were observed in both the 20 mg/kg (selected registrational dose) and 10 mg/kg1 DYNE-251 Q4W cohorts, through 12 and 18 months, respectively. Functional assessments included Stride Velocity 95th Centile (SV95C), North Star Ambulatory Assessment (NSAA), 10-Meter Walk/Run Time (10-MWR), and Time to Rise from Floor.
- Starting at the 6-month timepoint, the SV95C change from baseline observed in both the 10 mg/kg and 20 mg/kg cohorts of DELIVER exceeded the published proposed minimal clinically important difference (MCID).
- SV95C is a digital objective outcome measure of ambulatory performance in patients’ normal daily environment and is accepted as a primary endpoint for DMD clinical trials in Europe.
- Dystrophin expression: As previously reported, DYNE-251 demonstrated unprecedented near-full length dystrophin expression as measured by Western blot for patients with DMD who are amenable to exon 51 skipping. At the 6-month time point, patients treated with 20 mg/kg of DYNE-251 Q4W had a mean absolute dystrophin expression of 8.72% of normal (adjusted for muscle content). Dyne has confirmed that the U.S. Food and Drug Administration precedent for using dystrophin as a surrogate biomarker for accelerated approval remains available.
- Safety and tolerability: DYNE-251 has demonstrated a favorable safety profile based on 54 participants enrolled in the DELIVER trial. Since the prior update provided as of November 21, 2024, the safety profile remains unchanged, and no new treatment-related serious adverse events have been observed.
- 970 doses of study drug have been administered to date over a period of 77.1 patient-years of follow-up with some patients followed for up to ~2.5 years.
- 546 doses of study drug at the 20 mg/kg dose level have been administered to date.