The therapeutic environment for muscular dystrophy continues to evolve, with emerging approaches moving beyond traditional supportive care and toward treatments designed to address underlying disease mechanisms. Advances in targeted RNA therapeutics, muscle-directed delivery, cell therapy, and molecular approaches aimed at disease-specific drivers have expanded the number of potential treatment strategies under investigation across various neuromuscular disorders. These include therapies for Duchenne muscular dystrophy (DMD), myotonic dystrophy type 1 (DM1), and facioscapulohumeral muscular dystrophy (FSHD).
As several investigational agents progress through clinical development, researchers are increasingly focused not only on whether these therapies can modify the underlying biology of muscular dystrophy, but also on whether they can translate those effects into meaningful improvements in muscle function, disease progression, and quality of life. In honor of Muscular Dystrophy Awareness Month, held annually in September, NeurologyLive® shares eight emerging agents to watch across the muscular dystrophy treatment environment.
The FDA has accepted Capricor Therapeutics’ biologics license application (BLA) for deramiocel, as a potential therapy for DMD cardiomyopathy. The agency has scheduled a PDUFA date of August 31, 2025, and if approved, it would become the first cell-based treatment for DMD and the first official treatment for DMD cardiomyopathy.
Developed by Dyne Therapeutics, DYNE-302 is an investigational RNA-based therapy designed to target the underlying molecular driver of FSHD, aberrant expression of the DUX4 gene. The therapy combines a fragment antibody targeting transferrin receptor 1 (TfR1), which is highly expressed on muscle cells, with a small interfering RNA (siRNA) designed to reduce DUX4 messenger RNA and downstream DUX4 activity. Preclinical studies demonstrated robust and durable DUX4 suppression along with improvements in muscle structure and function.
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In July 2026, the FDA cleared Dyne’s investigational new drug application for a randomized, placebo-controlled, double-blind, multiple-ascending-dose phase 1 trial in ambulatory adults with FSHD, marking the program’s transition into clinical testing. SRP-1001 (formerly ARO-DUX4) is an investigational small interfering RNA (siRNA) therapy designed to reduce expression of DUX4, a key driver of FSHD-related muscle degeneration. Originally developed by Arrowhead Pharmaceuticals as ARO-DUX4, the program is being advanced by Sarepta Therapeutics and uses an αvβ6 integrin-targeted delivery approach intended to selectively deliver the RNAi therapy to skeletal muscle.
It is uncommon for gene-silencing therapies to combine antibody targeting with siRNA delivery, as the two modalities usually operate through distinct mechanisms. In this case, the transferrin receptor fragment directs the payload specifically to muscle cells, which could theoretically reduce off-target effects in other tissues. The agent is being evaluated in a randomized, placebo-controlled phase 1/2 study assessing safety, tolerability, pharmacokinetics, and pharmacodynamics in adolescents and adults with FSHD1.
In preliminary first-in-human data reported in March 2026, SRP-1001 demonstrated dose-dependent muscle exposure, with delivery to muscle tissue observed, along with reductions in creatine kinase and an acceptable early safety and tolerability profile. Further clinical development is planned to evaluate higher dose levels and better characterize the therapy’s potential effects on FSHD.
Exon-Skipping Therapies Advance for Duchenne Muscular Dystrophy
Zeleciment rostudirsen (z-rostudirsen; formerly DYNE-251) represents a targeted approach for a specific subset of DMD patients. The investigational therapy is designed to skip exon 51 during the splicing process of the dystrophin gene, aiming to restore the production of a partially functional protein. Dyne Therapeutics submitted a biologics license application to the FDA in May 2026 seeking accelerated approval for this agent in patients whose DMD is amenable to exon 51 skipping. This submission marks a major regulatory milestone for the company’s exon-skipping program.
The treatment strategy relies on antisense oligonucleotides to interfere with the pre-mRNA splicing mechanism. By targeting exon 51, the therapy seeks to alter the reading frame of the dystrophin gene, potentially allowing for the synthesis of a shorter but functional dystrophin protein. The BLA submission follows the completion of clinical data generation required for this regulatory pathway, positioning z-rostudirsen as a candidate to address the needs of a defined population within the DMD community.
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Myotonic Dystrophy Type 1 Trials Show Mixed Results
For myotonic dystrophy type 1, the investigational agents are showing varying degrees of success in clinical testing. Novartis announced in September 2026 that the phase 3 HARBOR study (NCT06411288) evaluating delpacibartetedesiran (del-desiran; formerly AOC 1001) did not meet its primary endpoint of video hand opening time (vHOT). This measure assesses myotonia, a condition characterized by delayed muscle relaxation after contraction. Despite the primary endpoint failure, the company confirmed evidence of clinical activity observed in secondary endpoints and exploratory analyses.
NeurologyLive® spoke with Doug Kerr, MD, PhD, chief medical officer at Dyne Therapeutics, who discussed the trial results. The data revealed consistent improvements across measures of myotonia, muscle strength, and CNS function, with sustained gains observed through 12 months. These findings have positioned z-basivarsen as a potential first-in-class therapy for DM1, with phase 3 plans slated for 2026.
FSHD and DM1 Approaches Seek Regulatory Clearance
The environment for facioscapulohumeral muscular dystrophy continues to expand with new data. In a number of company updates, Avidity Biosciences announced that the FDA has opened the pathway for an accelerated approval of delpacibart braxlosiran (del-brax). The company has also initiated its phase 3 FORWARD study (NCT07038200), a confirmatory, large-scale trial to further test the agent’s efficacy and safety. This study will serve as supportive evidence for a future regulatory submission.
For DM1, PGN-EDODM1 utilizes a peptide-conjugated phosphorodiamidate morpholino oligomer to target the toxic CUG repeat RNA. Using PepGen’s enhanced delivery oligonucleotide technology, the therapy is designed to enter skeletal muscle, bind pathogenic DMPK RNA, and release sequestered MBNL1 protein to restore normal RNA splicing. The agent is being evaluated in the phase 2 FREEDOM2-DM1 study (NCT06667453). Preliminary data from the 5 mg/kg cohort showed favorable tolerability and trends toward improved splicing and video hand-opening time. In August 2026, PepGen announced plans to advance the program to its highest planned dose of 12.5 mg/kg following a Data and Safety Monitoring Board review.