Design Therapeutics Gets Clearance To Start Dosing DM1 Participants In Phase 1 Multiple-Ascending Dose Study Of DT-818 In Australia In H1 2026

Design Therapeutics, Inc. (Nasdaq: DSGN), a clinical-stage biotechnology company developing treatments for serious degenerative genetic diseases, today announced progress and updated milestones across its portfolio of GeneTAC® candidates in addition to reporting financial results for the third quarter of 2025.

• oday, Design announced the nomination of DT-818, a GeneTAC® small molecule, as a development candidate for the treatment of DM1. The underlying cause of DM1 is a CTG repeat expansion in the DMPK gene, which DT-818 is designed to address by selectively reducing transcription of the mutant expanded allele.
• In preclinical studies, DT-818 has demonstrated a potential best-in-disease profile for DM1, including a greater than 90% reduction in toxic RNA foci in DM1 patient cells, corresponding splicing correction and selective targeting of mutant DMPK.
• The company has obtained ex-US regulatory clearance to initiate clinical development and plans to begin dosing DM1 patients in a Phase 1 multiple-ascending dose (MAD) trial of DT-818 in Australia in the first half of 2026 to assess safety and correction of mis-splicing, with splicing data expected in 2027.