Summary of Avidity Biosciences Update / Briefing (September 10, 2025) Company Overview - **Company**: Avidity Biosciences (NasdaqGM:RNA) - **Focus**: Development of RNA therapeutics, particularly for neuromuscular diseases such as Duchenne Muscular Dystrophy (DMD), Facioscapulohumeral Muscular Dystrophy (FSHD), and Myotonic Dystrophy [2][3] Key Points and Arguments Industry and Product Development - Avidity is preparing to launch three drugs in the neuromuscular space: DELBRAX for FSHD, Aldosterone for Myotonic Dystrophy, and Delzota for DMD [3][4] - The company aims to be the first to receive global approval for treatments targeting these rare diseases [4] DMD Focus - DMD is a severe condition affecting young boys, leading to loss of mobility and reduced life expectancy [5] - Approximately 900 boys in the US and Europe are amenable to exon 44 skipping treatment [5] Clinical Data and Efficacy - The EXPLORER 44 study showed unprecedented functional improvements in patients treated with Delzota, with significant reductions in creatinine kinase (CK) levels, indicating muscle health [6][22] - At the one-year mark, about 50% of participants had CK levels within the normal range, demonstrating long-term muscle protection [22][70] - Delzota treatment resulted in a 25% increase in dystrophin levels, approaching levels associated with a normal phenotype [18][21] Functional Improvements - Delzota-treated patients showed significant improvements in functional endpoints compared to matched natural history controls, with absolute improvements of over two seconds in various mobility tests [26][30] - The improvements are unprecedented in the context of DMD treatment, indicating a potential reversal of disease progression [34] Safety Profile - The safety profile of Delzota remains favorable, with most adverse events being mild or moderate [15][16] - Only one serious adverse event was deemed related to the treatment, highlighting the overall tolerability of the drug [16] Regulatory and Commercial Strategy - Avidity plans to submit its first Biologics License Application (BLA) by the end of 2025, with subsequent submissions for the other two drugs within a year [8][45] - The company is building a commercial infrastructure that leverages synergies across its product launches in the same therapeutic area [46][47] Future Outlook - Avidity anticipates continued functional improvements as long-term muscle protection is maintained [41] - The company is also exploring platform designation for future exon-skipping therapies, which could expedite development timelines [66] Additional Important Information - The company emphasizes the importance of delivering RNA therapeutics effectively to achieve significant clinical outcomes [40][73] - Avidity is committed to redefining possibilities for boys and young men living with DMD, aiming for a future where they can engage in normal activities [36][37] This summary encapsulates the critical insights from the Avidity Biosciences briefing, highlighting the company's innovative approach to treating neuromuscular diseases and the promising data supporting its lead product, Delzota.