Biopharmaceutical company Avidity Biosciences Inc (Nasdaq:RNA) announced on Tuesday that Japan's Ministry of Health, Labour and Welfare has granted Orphan Drug designation to delpacibart etedesiran (del-desiran) for the treatment of myotonic dystrophy type 1 (DM1).

Del-desiran is the first investigational therapy for DM1 to receive this designation in Japan.

DM1 is a progressive, life-threatening neuromuscular disease with no approved treatments. Del-desiran is designed to address the root cause of the disorder using Avidity's proprietary Antibody Oligonucleotide Conjugates platform.

The therapy has previously received Breakthrough Therapy, Orphan Drug and Fast Track designations from the US Food and Drug Administration (FDA), as well as Orphan designation from the European Medicines Agency (EMA).

Avidity has aligned with global regulatory bodies on the registrational strategy for del-desiran and is conducting the Phase 3 HARBOR study to support potential approvals. Participant enrolment is expected to conclude by mid-2025, with marketing applications planned for submission beginning in 2026 across the United States, European Union and Japan.

Japan's Orphan Drug programme supports treatments for conditions affecting fewer than 50,000 patients in the country and offers development incentives for therapies meeting high unmet medical needs.