Avidity Biosciences Wins Orphan Drug Designation in Japan for Delpacibart Etedesiran

Avidity Biosciences, Inc. announced that the Japan Ministry of Health, Labour and Welfare (MHLW) has granted Orphan Drug designation (ODD) to delpacibart etedesiran (del-desiran) for the treatment of myotonic dystrophy type 1 (DM1), an investigational treatment designed to address the root cause of DM1, an underrecognized, progressive and often fatal neuromuscular disease with no approved therapies. Del-desiran is the first investigational treatment for DM1 to receive Orphan Drug designation in Japan. Del-desiran has also received Breakthrough Therapy, Orphan Drug and Fast Track designations by the U.S. Food and Drug Administration (FDA) and Orphan designation by the European Medicines Agency (EMA).

“This decision by MHLW further reinforces the significant potential of del-desiran to address the root cause of DM1 and the urgent need to bring an approved therapy to the many people impacted by this devastating rare disease in Japan and around the world,” said Steve Hughes, M.D., chief medical officer at Avidity. “We are very encouraged by del-desiran data reported from the MARINA and MARINA-OLE studies thus far, demonstrating favorable long-term safety and tolerability, reversal of disease progression, and consistent and durable improvements in multiple clinical endpoints. Looking ahead, there are multiple key milestones this year as we complete enrollment in the phase 3 HARBOR trial and continue to advance our global commercialization preparations to potentially deliver the first globally approved drug for people living with DM1.”

Avidity has aligned with global regulators on the registrational path for del-desiran for the treatment of DM1, which informed the design of the ongoing Phase 3 HARBOR™ study. Avidity expects to complete participant enrollment in the Phase 3 HARBOR study in mid-2025 and submit marketing applications starting 2026 in the U.S., European Union and Japan.

Japan’s MHLW grants Orphan Drug designation to drugs in development for the treatment of diseases that affect fewer than 50,000 patients in Japan and for which there is a high unmet medical need. An investigational therapy is eligible to qualify for Orphan Drug designation if there is no approved alternative treatment option or if there is high efficacy or safety expected compared to existing treatment options. Orphan Drug designation provides certain benefits, including prioritized consultation regarding clinical development, reduced consultation fees, tax incentives, priority review of applications, reduced application fees, and extended registration validity period.