Avidity Biosciences(US:RNA) Prnewswire·2026-02-18 22:00Core Insights - The Phase 1/2 MARINA trial results for delpacibart etedesiran (del-desiran) indicate a significant reduction in DMPK mRNA levels and improvements in various clinical measures for myotonic dystrophy type 1 (DM1) patients [1][2] Group 1: Trial Results - Del-desiran achieved approximately 40% mean reduction in DMPK mRNA levels in muscle tissue [1] - Improvements were noted in myotonia, muscle function, strength, mobility, and patient-reported outcomes [1][2] - The trial involved 38 participants, with a randomized 3:1 allocation to del-desiran doses of 1 mg/kg, 2 mg/kg, or 4 mg/kg, or placebo [1] Group 2: Safety and Tolerability - Del-desiran demonstrated an acceptable safety profile, with most adverse events classified as mild or moderate [1] - The primary endpoint of the study focused on evaluating the safety and tolerability of del-desiran [2] Group 3: Future Developments - Avidity Biosciences is advancing the Phase 3 HARBOR study, which aims to be the first globally approved drug for DM1 [1] - The HARBOR trial is designed to assess del-desiran in approximately 150 participants aged 16 and older, with a primary endpoint of video hand opening time (vHOT) [1][2] - Enrollment for the HARBOR trial was completed in July 2025, with topline data expected in the second half of 2026 [1]