Exhibit 99.1 Dyne Therapeutics Reports Third Quarter 2025 Financial Results and Recent Business Highlights - Topline data from Registrational Expansion Cohort of DELIVER trial of zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251) in DMD on track for December 2025 to support potential submission for U.S. Accelerated Approval in Q2 2026 - - FDA recently granted Breakthrough Therapy Designation to z-rostudirsen for the treatment of patients with DMD amenable to exon 51 skipping - - U.S. sites activ ...