Avidity Biosciences, a biopharmaceutical firm dedicated to advancing RNA therapeutics through Antibody Oligonucleotide Conjugates (AOCs™), has revealed that the US Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to delpacibart etedesiran (AOC 1001), its leading clinical development program, for the treatment of myotonic dystrophy type 1 (DM1).

DM1 is a severely underrecognized neuromuscular disorder characterized by progressive muscle weakness and other debilitating symptoms. Despite its severity, there are currently no approved therapies for DM1, making the FDA's recognition of delpacibart etedesiran's potential all the more crucial.

Sarah Boyce, President and CEO at Avidity Biosciences, expressed her satisfaction with the FDA's decision, stating, "We are pleased that the FDA has granted Breakthrough Therapy designation to del-desiran for myotonic dystrophy type 1, underscoring the potential of del-desiran to be an effective treatment and the urgency of bringing this treatment to people living with DM1."

The company is wasting no time in advancing its clinical development program. Avidity has already commenced initiation for the global Phase 3 HARBOR™ study, which aims to evaluate the efficacy and safety of delpacibart etedesiran. The primary endpoint of the Phase 3 trial is video hand opening time (vHOT), with key secondary endpoints including muscle strength as measured by hand grip strength and quantitative muscle testing (QMT) total score, as well as activities of daily living assessed by DM1-Activ.

Recent data from the long-term MARINA-OLE™ study have provided encouraging insights into the potential of delpacibart etedesiran. These findings demonstrated a reversal of disease progression in adults with DM1 across multiple endpoints, including vHOT, muscle strength, and DM1-Activ, when compared to natural history data.

In addition to the Breakthrough Therapy designation, delpacibart etedesiran has received Orphan Drug and Fast Track designations from the FDA, as well as Orphan designation from the European Medicines Agency (EMA), further highlighting the significance of this therapeutic candidate in addressing the unmet needs of individuals living with DM1.