Avidity Biosciences(US:RNA) Prnewswire·2025-06-09 11:01Core Insights - Avidity Biosciences announced positive topline data from the Phase 1/2 FORTITUDE™ program for delpacibart braxlosiran (del-brax) in treating Facioscapulohumeral Muscular Dystrophy (FSHD), showing improvements in function, strength, and patient-reported outcomes compared to placebo [1][3][6] - The company plans to submit a Biologics License Application (BLA) for accelerated approval in the second half of 2026 [1][3] - Del-brax is the first investigational therapy targeting the underlying cause of FSHD by directly addressing the DUX4 gene, with no approved therapies currently available for this condition [2][13] Group 1: Clinical Data and Results - The FORTITUDE™ trial included a randomized, placebo-controlled, double-blind study evaluating 39 participants on doses of 2 mg/kg or 4 mg/kg of del-brax over 12 months [5][10] - Results indicated consistent improvements in functional mobility and muscle strength, as measured by the 10-Meter Walk-Run test, Timed Up and Go, and quantitative muscle testing [6][9] - Significant reductions in biomarkers such as KHDC1L and creatine kinase were observed, indicating muscle damage [6][7] Group 2: Safety and Regulatory Pathway - Del-brax demonstrated favorable long-term safety and tolerability, with most adverse events being mild or moderate, and no serious adverse events reported [7][9] - The U.S. FDA has opened the accelerated approval regulatory pathway for del-brax, and a global Phase 3 FORWARD™ study has been initiated [3][4] Group 3: Future Developments - The ongoing biomarker cohort of the FORTITUDE trial aims to assess the impact of del-brax on KHDC1L levels, with topline data expected in Q2 2026 [7][11] - Avidity is advancing its clinical development pipeline, focusing on RNA therapeutics through its proprietary Antibody Oligonucleotide Conjugates (AOCs™) platform [16]