Long-Term Safety and Efficacy of DT‑DEC01 Therapy in Ambulatory and Non-Ambulatory DMD Patients up to 24 Months after Systemic Administration

Topic:

Clinical Trials

Poster Number: 59 S

Author(s):

Maria Siemionow, MD, PhD, DSc, University of Illinois at Chicago, Dystrogen Therapeutics Corporation, Grzegorz Bieganski, MD, Poznan University of Medical Sciences, Poland, Jacek Wachowiak, MD, PhD, Poznan University of Medical Sciences, Poland, Jaroslaw Czarnota, MD, Hospital MedPolonia, Poland, Krzysztof Siemionow, MD, PhD, University of Illinois at Chicago, Dystrogen Therapeutics Corporation, Adam Niezgoda, MD, PhD, Poznan University of Medical Sciences, Poland, Anna Ziemiecka, MSc, Dystrogen Therapeutics Corporation, Katarzyna Bożyk, MSc, Dystrogen Therapeutics Corporation, Ahlke Heydemann, PhD, University of Illinois at Chicago, USA

Introduction:
Duchenne muscular dystrophy (DMD), a severe X-linked neuromuscular disorder characterized by progressive muscle degeneration, leads to loss of ambulation, cardiopulmonary decline and premature mortality. This study evaluated the long-term safety and efficacy of systemic intraosseous administration of DT-DEC01, a Dystrophin Expressing Chimeric (DEC) cell therapy designed to restore functional myofibers in ambulatory and non-ambulatory DMD patients.
Methods:
Seven DMD patients aged 6-16 years with different gene mutations, received a single DT-DEC01 dose in three cohorts (2×10⁶, 4×10⁶, and 6×10⁶ cells/kg) without immunosuppression. Safety was assessed by monitoring of Adverse Events (AE), Serious Adverse Events (SAE), and Donor-Specific Antibodies (DSA) over 24 months.
Efficacy measures included echocardiography (LVEF), spirometry (FVC), functional tests (6MWT, NSAA, PUL), grip strength (dynamometry), daily activity by step/arm movement counts, and electromyographic (EMG) analysis of Motor Unit Potentials (MUP) duration over 12 months.
Results:
No treatment-related AE, SAE or DSA were observed during the 24 months. Efficacy outcomes showed improvements in all treated patients:
Ambulatory patients (n=4, ages 6-7; deletion of exons 3-12; 20-29; 44; nonsense mutation) revealed sustained gains at 12 months: 6MWT of 10-18%, grip strength of 5-65%, maintenance of PUL scores, with step count increases of 10-74%. EMG revealed prolonged MUP duration across multiple muscles (deltoid 18-63%, biceps 32-152%, rectus femoris 11-72%, gastrocnemius 42-64%).
Non-ambulatory patients (n=3, ages 11-16; deletion of exons 48-50; 52, nonsense mutation) exhibited clinical improvements at 12 months: PUL by 6-15%, grip strength by 8-34%, FVC by 28-48%, LVEF by 11-17%, and arm movement counts by 92–185%. EMG showed increased MUP duration (deltoid 28-49%, biceps 29-150%).
Conclusions:
DT-DEC01 therapy demonstrated a favorable safety profile with no therapy-related AE, SAE, or DSA up to 24 months. Efficacy improvements were sustained up to 12 months in both ambulatory and non-ambulatory DMD patients in functional capacity (6MWT, NSAA, PUL), muscle strength, EMG, and activity levels, with additional gains in respiratory and cardiac function among non-ambulatory patients. These findings support DT-DEC01 as a broadly applicable therapeutic approach providing functional, muscular and organ-level improvements, independent of dystrophin gene mutation or disease stage.