Dyne Therapeutics (DYN) Study Result summary

Study Design and Objectives

• DELIVER trial evaluated z-rostudirsen in boys with DMD amenable to exon 51 skipping, using a global, randomized, placebo-controlled, double-blind Phase 1/2 design with both ambulatory and non-ambulatory patients.

• The trial included a multiple ascending dose phase and a registrational expansion cohort at 20 mg/kg every 4 weeks, with primary endpoints of dystrophin change at six months and safety/tolerability.

• Functional endpoints included TTR velocity, 10MWR velocity, NSAA, SV95C, PUL2.0, and FVC %p, with placebo-controlled and long-term extension periods.

• Baseline characteristics were well balanced across treatment and placebo groups, with a broad age range (4–16 years).

• Long-term open-label extensions assessed durability of functional improvements up to 24 months.

Key Efficacy and Functional Results

• The trial met its primary endpoint, showing a statistically significant 5.46% increase in muscle content-adjusted dystrophin at six months (p<0.0001), representing a 7-fold increase from baseline.

• Unadjusted dystrophin reached 2.87% at six months, about 10-fold higher than standard of care (eteplirsen).

• Functional improvements were observed across all six prespecified endpoints at six months, including TTR velocity and 10MWR velocity, both with nominal p<0.05 versus placebo.

• Sustained functional improvements were observed across all measures out to 24 months in long-term data.

• Lung function, as measured by FVC % predicted, was preserved at six months compared to a decline in placebo.

Safety and Tolerability

• Favorable safety profile at 20 mg/kg Q4 weeks, with most treatment-emergent adverse events mild or moderate (fever, headache most common).

• No persistent related anemia or thrombocytopenia observed at the go-forward dose.

• Two related serious adverse events (malaise/fever) occurred in the long-term extension, both resolved with continued treatment.

• Over 1,400 doses and 113 patient-years of follow-up support long-term safety.

• Safety profile remained favorable up to 36 months in 86 participants.