Dyne Therapeutics announced additional positive data from the ongoing phase-I/II DELIVER clinical trial of zeleciment rostudirsen (Z-rostudirsen, also known as DYNE-251), in individuals with Duchenne Muscular Dystrophy (DMD) amenable to exon 51 skipping. These data are being presented in a late-breaking poster presentation at the 2026 Muscular Dystrophy Association (MDA) Clinical and Scientific Conference being held from 8^th to 11^th March, 2026 in Orlando.

“This week, we are presenting additional analyses of 24-month data from the DELIVER trial showing the breadth of potential benefits Z-rostudirsen may bring to individuals with exon 51 skip amenable DMD beyond the previously reported unprecedented improvements in muscle function. Cardiopulmonary issues are a key area of concern in DMD, so we are particularly encouraged by new analyses showing improvement in both heart and lung function out to 24 months. We attribute these results to the differentiated capabilities of our FORCE platform to deliver therapeutics to a broad range of muscles, including the heart, trunk and diaphragm, as well as the CNS,” said Doug Kerr, MD, PhD, Chief Medical Officer (CMO), Dyne.

Dyne announced the results of new analyses of cardiac and pulmonary function amongst all DELIVER participants who were randomised to Z-rostudirsen treatment at baseline (any dose1) and for whom cardiac magnetic resonance imaging and/or pulmonary function data were available.

Improvement from baseline in lung function, as measured by Forced Vital Capacity Percent Predicted (FVC%p), was observed through 24 months, as compared to the expected decline estimated in published natural history data.

Improvement from baseline was observed through 24 months in circumferential strain, an early signal of cardiac performance, as compared to the expected worsening estimated in published natural history data5,6.

Improvement from baseline in left ventricular ejection fraction, a measure of how well the heart is pumping, was observed at 24 months, in contrast with the expected decline estimated in published natural history data.

In previously reported safety and tolerability data from 86 total participants enrolled in the DELIVER trial and followed for up to 36 months, Z-rostudirsen demonstrated a favourable safety profile, and most related Treatment Emergent Adverse Events (TEAEs) were mild or moderate. The most commonly reported related TEAEs were pyrexia (fever) and headache. No related serious TEAEs were observed in the REC.

These data will be presented in a poster titled “Zeleciment rostudirsen led to trends in long-term improvement in clinical outcomes including cardiopulmonary function: Additional data from DELIVER” (poster # 476 LBT).