Design Therapeutics stock plunges on trial results for neuromuscular disease treatment

Shares of Design Therapeutics Inc. DSGN dropped 45% in premarket trading Tuesday after the biopharma company reported mixed results from an early-stage trial of a treatment for Friedreich ataxia, a genetic neuromuscular disease. The phase 1 trial of the treatment, DT-216, confirmed clinical activity in patients with the disease but also found injection-site reactions, the company said in a release late Monday. While the findings support the continued development of the treatment, Design said it will improve the formulation to address the injection-site reactions and begin another early-stage trial in the second half of…