Dyne Therapeutics Receives FDA Breakthrough Therapy Designation for DYNE-251 in Duchenne Muscular Dystrophy Treatment

Dyne Therapeutics' DYNE-251 has been granted Breakthrough Therapy Designation by the FDA for treating Duchenne muscular dystrophy. The designation is based on data from the ongoing DELIVER clinical trial, which showed sustained functional improvement and near-full-length dystrophin expression. The therapy has the potential to deliver meaningful benefits to patients for whom exon 51 skipping is applicable.

Dyne Therapeutics, Inc. (Nasdaq: DYN) has received a significant milestone in its efforts to develop a breakthrough therapy for Duchenne muscular dystrophy (DMD). The U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to DYNE-251, an investigational therapeutic being evaluated in the Phase 1/2 global DELIVER clinical trial [1].

The designation is based on data from the ongoing DELIVER trial, which has demonstrated sustained functional improvement and near-full-length dystrophin expression in individuals with DMD who have mutations in the DMD gene amenable to exon 51 skipping. DYNE-251 consists of a phosphorodiamidate morpholino oligomer (PMO) conjugated to an antigen-binding fragment (Fab) that binds to the transferrin receptor 1 (TfR1), enabling the production of near full-length dystrophin in muscle and the central nervous system (CNS) to provide functional improvement [2].

The Breakthrough Therapy Designation offers Dyne several advantages, including enhanced FDA support, early and frequent communication with FDA reviewers, and eligibility for rolling and Priority Review, potentially reducing the Biologics License Application (BLA) review timeline from 12 to 8 months. DYNE-251 has also been granted Fast Track, Orphan Drug, and Rare Pediatric disease designations by the FDA and Orphan Drug designation by the European Medicines Agency (EMA) for the treatment of DMD [1].

Dyne has completed enrollment of 32 patients in the Registrational Expansion Cohort of the DELIVER trial, with data from this cohort expected in late 2025. The company anticipates a potential BLA submission for U.S. Accelerated Approval in early 2026, following the completion of data collection and analysis from the registrational expansion cohort [1].

Duchenne muscular dystrophy is a rare, X-linked, recessive, progressive neuromuscular disorder that affects approximately 12,000 individuals in the U.S. and approximately 16,000 in the EU. The disease results from mutations in the DMD gene, leading to total absence or nearly undetectable levels of dystrophin protein, essential for muscle structure, function, and preservation. There is a significant unmet need for new treatment options that deliver functional improvement [2].

Dyne Therapeutics is focused on delivering functional improvement for people living with genetically driven neuromuscular diseases. The company is advancing clinical programs for myotonic dystrophy type 1 (DM1) and Duchenne muscular dystrophy (DMD), and preclinical programs for facioscapulohumeral muscular dystrophy (FSHD) and Pompe disease [2].

References:
[1] https://investors.dyne-tx.com/news-releases/news-release-details/dyne-therapeutics-announces-fda-breakthrough-therapy-0
[2] https://www.marketscreener.com/news/dyne-therapeutics-inc-announces-fda-breakthrough-therapy-designation-for-dyne-251-in-duchenne-musc-ce7c5edadc8eff20