Avidity Biosciences Receives FDA Breakthrough Therapy Designation for Delpacibart Zotadirsen (del-zota) for the Treatment of DMD in People with Mutations Amenable to Exon 44 Skipping

Core Insights - Avidity Biosciences has received Breakthrough Therapy designation from the FDA for delpacibart zotadirsen (del-zota) aimed at treating Duchenne muscular dystrophy (DMD) in patients with mutations suitable for exon 44 skipping [1][4][7] - The company is on track for a Biologics License Application (BLA) submission by the end of 2025, with ongoing preparations for a potential U.S. launch of del-zota following FDA approval [5][4] - Del-zota is currently in the Phase 2 EXPLORE44 Open-Label Extension trial, building on positive results from the Phase 1/2 trial that showed significant improvements in biomarkers related to DMD [2][4][10] Company Overview - Avidity Biosciences focuses on developing a new class of RNA therapeutics known as Antibody Oligonucleotide Conjugates (AOCs™) [13] - The company aims to address rare neuromuscular diseases, including DMD, myotonic dystrophy type 1 (DM1), and facioscapulohumeral muscular dystrophy (FSHD) [13] - Avidity's proprietary AOC platform allows for targeted delivery of RNA into muscle tissue, which is a significant advancement in the field of RNA therapeutics [13] Product Development - Del-zota is designed to deliver phosphorodiamidate morpholino oligomers (PMOs) to specifically skip exon 44 of the dystrophin gene, facilitating the production of near-full length dystrophin [3][12] - The Phase 1/2 EXPLORE44 trial demonstrated statistically significant increases in exon skipping and dystrophin production, along with a reduction in creatine kinase levels to near normal [4][12] - The ongoing EXPLORE44-OLE study will evaluate the long-term safety and efficacy of del-zota, with a total treatment duration of approximately 24 months [9][10] Regulatory Designations - In addition to Breakthrough Therapy designation, del-zota has received Orphan designation, Rare Pediatric Disease designation, and Fast Track designation from the FDA [7][12] - These designations highlight the drug's potential to significantly improve treatment options for patients with DMD, a condition with a high unmet medical need [11][6]