Dyne Therapeutics' DYNE-101 Shows One-Year Functional Gains in DM1 Trial; Stock Rises After Hours

Dyne Therapeutics (DYN) reported additional one-year data from the Phase 1/2 ACHIEVE trial on September 29, 2026, showing that zeleciment basivarsen (DYNE-101) improved multiple functional measures in patients with myotonic dystrophy type 1 (DM1). The data demonstrated functional improvement versus baseline, placebo, and a matched natural history cohort. Continued benefits were observed at six months in video hand opening time (vHOT), an emerging indicator of clinical benefit in DM1. Dyne said topline data from the registrational expansion cohort of ACHIEVE remain on track for the first quarter of 2027 and could support a potential U.S. Accelerated Approval submission in the third quarter of 2027. Shares closed at $16.21, down 0.80%, and rose 3.33% to $16.75 in after-hours trading.