Design Therapeutics Reports Initial Results from Phase 1 Multiple-Ascending Dose Study of DT-216 for the Treatment of Friedrich Ataxia

DT-216 Resulted in a Significant Increase in FXN mRNA Levels in Skeletal Muscle of FA Patients

Treatment Generally Well-Tolerated; Injection Site Reactions Attributable to Current Formulation Composition

Design Plans to Proceed with an Improved DT-216 Formulation and Initiate a Multiple Dose Phase 1 Clinical Study in the Second Half of 2024

Conference Call and Webcast to be Held Today at 4:30pm ET

CARLSBAD, Calif., Aug. 14, 2023 (GLOBE NEWSWIRE) -- Design Therapeutics, Inc. (Nasdaq: DSGN), a clinical-stage biotechnology company developing treatments for serious degenerative genetic diseases, today reported initial results from the company’s Phase 1 multiple-ascending dose (MAD) clinical trial of DT-216 in patients with Friedrich ataxia (FA). As of a data cutoff date of August 7, 2023, results showed that DT-216 was generally well-tolerated and achieved a statistically significant and dose-related increase in frataxin (FXN) mRNA levels in skeletal muscle biopsies.

FA is a multisystem degenerative disease caused by a GAA nucleotide repeat expansion in the FXN gene that impairs transcription and reduces FXN mRNA. Low FXN expression results in mitochondrial and cellular dysfunction and leads to all FA disease manifestations. DT-216 is a GeneTAC small molecule designed to specifically target the GAA repeat expansion mutation, unblock the transcriptional machinery, and restore the production of functional, natural FXN mRNA.

“I’m encouraged by the data from the Phase 1 MAD trial of DT-216, which is the first to show a drug candidate increasing transcription of endogenous FXN mRNA in an affected tissue in FA,” said Susan Perlman, M.D., Clinical Professor of Neurology and Director of Neurogenetics Clinical Trials at UCLA. “Given the lack of treatment options to address the root cause of this debilitating disease, DT-216 is a highly promising candidate, and I am eager to see its continued development.”

Observational Biomarker Study in Friedreich Ataxia
In parallel to the Phase 1 MAD study, Design conducted an observational study to evaluate FA biomarker assays in blood and skeletal muscle from individuals with FA, FA carriers and normal healthy volunteer controls for use in DT-216 interventional studies. The company developed procedures and methods to measure both FXN mRNA and FXN protein in muscle. Initial data from the observational study is based upon a data cutoff of August 7, 2023. The observational study enrolled a total of 56 participants. Skeletal muscle biopsies were obtained from study participants at two visits several days apart to measure FXN mRNA and protein levels and characterize inter-and intra-individual variability.