The Food and Drug Administration has accepted Dyne Therapeutics’ application for its investigational Duchenne muscular dystrophy therapy, setting a target action date of Jan. 21, 2027.
Oppenheimer said to investors in a note on Monday, “We anticipate a smooth approval,” adding that the therapy, dubbed zeleciment rostudirsen (z-rostudirsen), is poised to “capture the majority of market share,” given stronger dystrophin benefits and a more convenient dosing profile than the current standard treatment.
Sarepta Therapeutics’ Exondys 51 is currently considered a standard of care regimen for patients with Duchenne muscular dystrophy who are amenable to exon 51 skipping. However, Jefferies said in a Monday note that Dyne could challenge Exondys with z-rostudirsen, which in the Phase 1/2 DELIVER trial outperformed Sarepta’s asset. Jefferies described the early data cut as “best-in-class.” The firm also noted that Exondys is dosed weekly while z-rostudirsen is designed to be given once every four weeks—a “convenient” profile. Jefferies continued by saying, “z-rostudirsen could command a pricing premium” if approved and expects uptake to be “robust” across three key patient subgroups: those yet to undergo Exondys treatment, those who have discontinued Sarepta’s therapy, and those currently receiving it.
Dyne is seeking accelerated approval for z-rostudirsen in patients with Duchenne muscular dystrophy amenable to exon 51 skipping. Topline data from the registrational cohort of DELIVER released December 2025 showed a 5.46% increase at six months in concentrations of the dystrophin protein—a key disease marker—alongside improvements in functional measures such as time-to-rise velocity and the 10-meter walk/run test. Lung function was preserved at six months.
According to Stifel analysts quoted by Tristan Manalac on Dec. 8, 2025, Dyne’s exon-skipping therapy zeleciment rostudirsen resulted in an approximately sevenfold increase in dystrophin levels at six months and elicited functional improvements that are described as the "best ever" for this treatment class.
The FDA does not plan on holding an advisory committee meeting for z-rostudirsen, according to Dyne. Jefferies models more than $500 million in peak sales for z-rostudirsen but calls this estimate "conservative." Oppenheimer did not provide a peak forecast but noted that Dyne’s therapy could secure a "majority" of the $1.5 billion exon-51 DMD market.
