Dyne Therapeutics (DYN) investor relations material

Study Design and Objectives

• DELIVER was a global, randomized, placebo-controlled, double-blind Phase 1/2 trial evaluating z-rostudirsen in boys with DMD amenable to Exon 51 skipping, focusing on functional improvement and dystrophin production.

• The trial included a multiple ascending dose phase and a registrational expansion cohort at 20 mg/kg every 4 weeks, enrolling 86 participants aged 4–16, both ambulant and non-ambulant.

• Primary endpoint was change in dystrophin at six months; functional endpoints included TTR velocity, 10MWR velocity, NSAA, SV95C, PUL2.0, and FVC %p.

• Functional assessments were pre-specified and included time to rise, 10-meter walk/run, North Star Ambulatory Assessment, stride velocity 95th centile, upper limb function, and forced vital capacity.

• Long-term open-label extension data were collected to assess durability of effect.

Key Efficacy and Functional Results

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

• Dystrophin production was approximately tenfold higher than current standard of care, with unadjusted dystrophin reaching 2.87% at six months.

• All six functional endpoints improved versus placebo at six months; time to rise and 10-meter walk/run velocities achieved nominal p<0.05.

• Sustained functional improvement was observed across all measures out to 18 and 24 months in long-term data.

• Lung function, as measured by FVC % predicted, was preserved at 6 months compared to a decline in placebo.

Safety and Tolerability

• Safety profile was favorable, with most adverse events mild or moderate; serious events were rare and resolved without long-term effects.

• No persistent related anemia or thrombocytopenia observed at the 20 mg/kg dose.

• Most common related adverse events were fever and headache; two serious events (fever/malaise) resolved without dose interruption.

• Over 1,400 doses administered at the 20 mg/kg level, representing 113 patient-years of follow-up.

• Safety and tolerability were maintained up to 36 months in 86 participants.