Avidity Biosciences completes enrollment in Phase 3 HARBOR clinical trial

Avidity Biosciences (RNA) announced the completion of enrollment in the ongoing global Phase 3 HARBOR clinical trial of delpacibart etedesiran, or del-desiran, for people living with myotonic dystrophy type 1, or DM1. Topline data from HARBOR, the first global Phase 3 clinical trial in DM1, are anticipated in the Q2 of 2026. Prior to initiation of the HARBOR trial, Avidity aligned with global regulators, including FDA, on the registrational path for del-desiran. The Company plans to submit marketing applications beginning in the second half of 2026 including in the United States, European Union and Japan. Del-desiran is an investigational treatment designed to address the underlying genetic cause of DM1, a rare, hereditary, progressive neuromuscular disease that shortens life expectancy and requires life-long care. DM1 is characterized by multisystemic manifestations including myotonia and progressive muscle weakening and may be underrecognized because it presents heterogeneously across skeletal, cardiac, and smooth muscles, leading to impairment of the cardiovascular, gastrointestinal, respiratory, ocular, and/or endocrine systems. Currently, there are no approved drugs for people living with DM1.