Dystrogen Therapeutics’ Cell Therapy DT-DEC01 Shows Long-Term Safety in Nonambulatory Duchenne Muscular Dystrophy
The findings were presented at the 2025 Muscular Dystrophy Association Clinical & Scientific Conference
This article originally appeared on our sister site, NeurologyLive®.
Dystrogen Therapeutics' DT-DEC01, an investigational dystrophin expressing chimeric cell therapy (DEC), demonstrated safety over a 24-month period in nonambulator patients with Duchenne muscular dystrophy (DMD).1
Along with improvements on functional tests, the results support the development of the cell therapy product for patients with DMD, regardless of their specific mutation or the state of their disease progression. The findings were presented at the 2025 Muscular Dystrophy Association (MDA) Clinical & Scientific Conference, held March 16-19 in Dallas, Texas.
The analysis, which was led by Maria Siemionow, MD, PhD, DSc, professor and director of Microsurgery Research at the University of Illinois, featured 24-month data on 3 patients, aged 11 to 16, who received doses of 2x106, 4x106, and 6x106 cells per kg of body weight, respectively, without immunosuppression. There were no cases of study-related adverse events (AEs), serious AEs, or donor-specific antibodies (DSA) recorded in up to 24 months of follow-up.
DT-DEC01 was delivered to the bone marrow compartment of the patient’s iliac crest by intraosseous administration. This procedure, which took place under anesthesia, came after patients underwent bone marrow aspiration to make space before the injection, which lasted on average 7 minutes. Twenty-four hour hospitalization and close monitoring for any potential responses associated with the procedure was part of the protocol after administration.
It was reported that a 15-year-old patient with exon 48-50 deletion (Patient 1) experienced improvements in echocardiography EF by 12%, arm movements by 9%, and Motor Unit Potentials (MUP) duration, both in deltoideus (53%) and biceps brachii (23%) at 18 months. Patient 1 also achieved improvements in PUL 2.0 test score by 5%, grip strength by 6%, and spirometry by 17% after 24 months from the original procedure.
Patient 2, an 11-year-old with exon 52 deletion, demonstrated a 17% improvement in echocardiography EF at 12 months, along with a 5% increase in PUL 2.0 test score and enhancements in MUP duration, including 19% in the deltoideus and 51% in the biceps brachii, at 18 months. In addition, this patient experienced a 59% improvement in spirometry and a remarkable 1150% increase in arm movements at 24 months posttreatment.
Patient 3, a 16-year-old with a nonsense mutation, reported improvements at 12 months post-DT-DEC01 administration, including a 6% increase in PUL 2.0 test score, a 34% improvement in grip strength, an 11% enhancement in echocardiography EF, and increases in MUP duration, with 49% in the deltoideus and 29% in the biceps brachii.
DT-DEC01 involves fusing allogeneic human myoblasts with autologous myoblasts from the patient. These chimeric cells express normal dystrophin and increase functional myoblasts, reduce inflammation, and replace fibrotic tissue, leading to improved muscle strength and function. DEC therapy also minimizes immune response and eliminates the need for immunosuppression, as the cells are recognized as "self." This approach aims to restore dystrophin and prevent the early loss of mobility and premature mortality in DMD patients.2
In the 12-month published data, the study's authors wrote that the findings "supports the potential benefits of DT-DEC01 therapy in improving cardiac, respiratory and skeletal muscle function in patients with DMD after systemic-intraosseous administration, providing hope for better outcomes and enhanced quality of life for DMD patients. Additionally, this study also highlights use of EMG as a valuable biomarker for monitoring functional changes in muscles affected by DMD after DT-DEC01 therapy."3
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