Shares of Dyne Therapeutics (NASDAQ:DYN) fell 31% Tuesday after the company released new data from a clinical trial called DELIVER for its drug DYNE-251 in the treatment of Duchenne muscular dystrophy, or DMD, and announced senior management changes.

Dyne said data from a Phase 1/2 study of DYNE-251 in DMD patients who are amenable to exon 15 skipping demonstrated “unprecedented dystrophin expression and functional improvement in multiple cohorts,” according to a statement.

The company added it was initiating registrational cohorts in the DELIVER trial. It intends to provide updates on the paths for registration for DYNE-251 and DYNE-101, which it has been evaluating for the treatment of myotonic dystrophy type 1, by the end of the year.

Dyne also announced that its chief medical officer was stepping down, but will stay until the end of the year to assist in the company’s ongoing clinical programs. It added that its chief operating officer and chief business officer were leaving the company to pursue other opportunities.

Several other companies are also engaged in developing therapeutics to treat DMD. Companies with DMD products already on the market or in development include Sarepta (SRPT), Pfizer (PFE), Catalyst (CPRX), Edgewise Therapeutics (EWTX), Satellos (OTC:MSCLF), Entrada (TRDA), PepGen (PEPG), Regenxbio (RGNX), Wave Life Sciences (WVE), Vertex Pharmaceuticals (VRTX), Solid Biosciences (SLDB), Capricor (CAPR), Avidity (RNA), and Roche (OTCQX:RHHBY).