Dyne Therapeutics announced on Mar. 10 that its investigational exon skipping therapy, z-rostudirsen (zeleciment rostudirsen), maintained respiratory and heart benefits through two years of follow-up in a Phase 1/2 study for Duchenne muscular dystrophy.
The findings are significant as they suggest the therapy could offer lasting improvements for patients with Duchenne who are amenable to exon 51 skipping, an area where treatment options remain limited. The company said these results support the strong profile of z-rostudirsen and build on previously released data positioning it as a competitive option.
Stifel analysts told investors that "while these results are in small samples and compared to external controls, the cardiac endpoints in particular are unlikely to be influenced by bias, and altogether these data further support the benefit/risk of z-rostudirsen, which in our view already had a best-in-class profile." Dyne did not disclose specific data from the DELIVER study but stated that improvements in lung function were maintained through 24 months of follow-up. The company used natural history data as a comparator, which showed expected declines in untreated patients.
In addition to respiratory outcomes, Dyne reported sustained cardiovascular effects over two years, including improvements in circumferential strain and left ventricular ejection fraction—measures of cardiac performance. Safety data from up to 36 months of follow-up indicated that most adverse events were mild or moderate.
These results add to December 2025 findings showing increased dystrophin expression levels and functional improvements such as time-to-rise and walk/run tests. Stifel previously said z-rostudirsen demonstrated "best ever" functional outcomes for this drug class. In contrast, other therapies like Sarepta Therapeutics’ Vyondys 53 and Amondys 54 failed to show significant motor function improvement in recent studies but continue seeking full approval.
Looking ahead, Dyne plans to submit z-rostudirsen for regulatory review in the second half of 2026. Stifel said this process may be positively affected by the upcoming departure of Vinay Prasad from his role at the Food and Drug Administration’s Center for Biologics Evaluation and Research.
