08:09 AM EDT, 06/17/2025 (MT Newswires) -- Dyne Therapeutics ( DYN ) said Tuesday that the Food and Drug Administration has granted breakthrough therapy designation to its investigational drug DYNE-101 for the treatment of myotonic dystrophy type 1

The company also submitted a revised protocol for its trial, which uses video hand opening time as the primary endpoint at six months compared to placebo, following a Type C meeting with the FDA in May.

Dyne said the trial will enroll 60 participants, randomized three to one to receive DYNE-101 or placebo, with additional clinical sites being added in the US to support enrollment.

Enrollment in the trial is expected to be completed by Q4, with data in mid-2026 and a submission planned for late 2026, the company said, adding that a confirmatory phase 3 trial will begin in early 2026.

Dyne shares were more than 21% lower in premarket trading.