Groundbreaking Genetic Treatment Focuses on Combating Duchenne Muscular Dystrophy
As advancements in medical research continue to unfold, two particularly notable areas of focus are gene therapies for Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA).
Duchenne Muscular Dystrophy (DMD)
Duchenne muscular dystrophy is a genetic condition that predominantly affects boys, manifesting in muscle weakness that typically becomes apparent at a young age. The disease progresses rapidly, often leading to significant disability by the time the individual reaches their 20s or early 30s, with symptoms eventually spreading to the heart and muscles responsible for breathing.
Several experimental therapies for DMD are currently in advanced development stages, and clinical trials are underway. These therapies have received designations such as Orphan, Breakthrough, and Fast Track from the FDA, signifying their potential significance. However, as of August 2025, none of these therapies have received full FDA approval.
For instance, Precision Biosciences' gene-editing therapy, PBGENE-DMD, aims to edit exons 45 to 55 in the DMD gene to produce a shortened yet functional dystrophin protein. This therapy could potentially benefit up to 60% of DMD patients and is still in preclinical to early clinical stages.
Another promising therapy is REGENXBIO’s RGX-202, designed to deliver a microdystrophin transgene. This therapy is currently in a pivotal Phase II/III clinical trial called AFFINITY DUCHENNE, with a potential Biologics License Application filing planned for 2026.
Dyne Therapeutics’ DYNE-251 has received FDA Breakthrough Therapy designation due to encouraging early clinical trial data showing functional improvements in patients. They plan to submit for accelerated FDA approval in early 2026 pending further trial results.
Sarepta Therapeutics’ Elevidys gene therapy, which is administered as a single intravenous dose, had an FDA voluntary hold on administration to ambulatory patients lifted after investigation found safety concerns unrelated to the gene therapy.
Spinal Muscular Atrophy (SMA)
In contrast to DMD, the first gene therapy for SMA, called Zolgensma, was approved by the FDA in May 2019. This therapy delivers a functional copy of the SMN1 gene via an adeno-associated virus vector to halt disease progression in infantile-onset SMA.
Clinical Trials and Research in the U.S.
In Rochester, New York, children were among the first in the nation to receive an experimental treatment for DMD as part of a clinical trial. The University of Rochester Medical Center (URMC) will be the lead study site for an experimental gene therapy for CNL5 Batten disease, and URMC was one of the first three sites in the nation to start dosing patients in the aforementioned clinical trial.
Dr. Emma Ciafaloni, a neuromuscular neurologist with URMC, is leading the Rochester study site for a phase 3 placebo-controlled clinical trial for a gene therapy being developed by Sarepta Therapeutics for children with DMD. This gene therapy has received accelerated approval from the FDA for the treatment of ambulatory pediatric patients aged 4 through 5 years with DMD and a confirmed mutation in the DMD gene.
In 2018, Dr. Ciafaloni successfully convinced the state to add SMA to the list of newborn tests. She is also currently working to get DMD added to the New York State Newborn Screening Program.
The new treatment for DMD consists of a single infusion that delivers a separate and potentially functional "micro" version of the dystrophin gene into muscle cells. This therapy aims to take over production of dystrophin, an important muscle building protein largely absent in people with DMD.
Sources:
- Precision Biosciences' PBGENE-DMD Receives FDA Orphan Drug Designation for Duchenne Muscular Dystrophy
- REGENXBIO’s RGX-202 Gene Therapy for Duchenne Muscular Dystrophy Receives FDA Orphan, Rare Pediatric Disease, and Fast Track Designations
- Dyne Therapeutics' DYNE-251 Receives FDA Breakthrough Therapy Designation for Duchenne Muscular Dystrophy
- Sarepta Therapeutics' Elevidys Gene Therapy for Duchenne Muscular Dystrophy Lifts FDA Voluntary Hold on Administration to Ambulatory Patients
- Sarepta Therapeutics' Gene Therapy Programs Face Setbacks, Impacting Patient Expectations
- Zolgensma: The First Gene Therapy for Spinal Muscular Atrophy
- URMC Leading Clinical Trial for Experimental Gene Therapy for CNL5 Batten Disease
- URMC One of First Three Sites to Start Dosing Patients in Clinical Trial for Gene Therapy for Duchenne Muscular Dystrophy
- FDA Approves Accelerated Approval for Sarepta Therapeutics' Gene Therapy for the Treatment of Ambulatory Pediatric Patients Aged 4 Through 5 Years with Duchenne Muscular Dystrophy
Science focuses on advancements in medical-conditions like Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), with chronic-diseases such as these increasingly becoming areas of interest. For instance, clinical trials for DMD therapies like Precision Biosciences' PBGENE-DMD and Sarepta Therapeutics' gene therapy are ongoing, with the latter receiving accelerated approval for ambulatory pediatric patients. In contrast, science has already made significant progress in treating SMA, with the first gene therapy, Zolgensma, receiving FDA approval in May 2019. The health-and-wellness sector is also investing in therapies-and-treatments for chronic-kidney-disease, with several experimental therapies currently in development stages.
