Allogeneic Heart-Derived Cell Therapy Deramiocel Delays Upper Limb Degeneration by 54% in Late-Stage Duchenne Muscular Dystrophy Patients
Background
Duchenne muscular dystrophy (DMD) is a hereditary muscle rare disease caused by a genetic defect on the X chromosome, leading to a deficiency in the dystrophin protein. It primarily affects young boys, and over time, the muscles rapidly degenerate. Patients typically lose the ability to walk entirely and become dependent on ventilators due to respiratory muscle paralysis, and combined with heart muscle dysfunction, they face a tragic clinical course leading to death in early adulthood. The current standard drug therapy is the prescription of glucocorticoids, which only temporarily delays symptom progression but does not prevent muscle degeneration itself.
In particular, recent developments in gene therapy and exon-skipping therapies have opened new treatment opportunities for ambulatory patients in the early stages. However, treatment options for late-stage patients who rely on wheelchairs remain extremely limited. Existing therapies focus on compensating for dystrophin within muscle cells, and thus show clear limitations in stages involving muscle tissue destruction and fibrosis, as well as systemic inflammation control. Therefore, a completely different approach was urgently needed to prevent the decline in upper limb function and heart function, which significantly affect the quality of life for late-stage patients.
Key Findings
Researchers at Capricor Therapeutics in the United States conducted a phase 3 clinical trial (HOPE-3) to investigate the efficacy of the allogeneic heart-derived cell therapy (cardiosphere-derived cells, CDCs) known as deramiocel. The study included 106 patients aged 10 years or older. Designed as a multi-center, randomized, double-blind trial, participants received deramiocel or a placebo intravenously at three-month intervals.
At the 12-month follow-up, the PUL 2.0 (Performance of the Upper Limb 2.0) score, which evaluates upper limb function, showed that the deramiocel-treated group experienced a 54% slower decline in function compared to the placebo group (p=0.029). This indicates that the hand and arm functions of late-stage patients who rely on wheelchairs were significantly preserved.
The therapy also demonstrated excellent cardiac protective effects. Analysis of cardiac MRI showed that deramiocel reduced the decline in left ventricular ejection fraction (LVEF), a measure of the heart's pumping ability, by 91% compared to the placebo group. Additionally, it successfully slowed the progression of myocardial scar, indicating permanent heart muscle damage. Safety assessments also received a passing score, as the treatment was well-tolerated without specific immune reactions or serious side effects.
Significance and Outlook
This study has drawn academic attention for its departure from traditional approaches that aim to directly compensate for the defective dystrophin protein, instead utilizing the anti-inflammatory and anti-fibrotic capabilities of exosomes secreted by heart cells. Deramiocel works by sending intercellular signaling molecules to reconstruct the microenvironment of damaged muscle tissue in a healthy manner.
Such a multifaceted mechanism offers a treatment alternative for late-stage patients facing life-threatening cardiopulmonary muscle weakness. In particular, the clinical data showing simultaneous prevention of left ventricular systolic dysfunction and myocardial fibrosis opens a path to delaying the onset of heart failure, the leading cause of death in DMD.
Even after passing regulatory hurdles, many challenges remain. Simplifying the production process of the cell therapy and setting a reasonable drug price are essential to ensuring patient access. The impact of the three-monthly intravenous administration schedule on patients' daily lives must also be minimized.
Duchenne muscular dystrophy (DMD) is a severe genetic neuromuscular disease caused by the absence of functional dystrophin, a large structural protein encoded by the X-chromosomal DMD gene. It is typically diagnosed in boys during early childhood and leads to progressive muscle degeneration, resulting in loss of ambulation, respiratory insufficiency requiring non-invasive ventilation, cardiomyopathy, and premature death in early adulthood.1 Glucocorticoids remain the cornerstone of pharmacological treatment.
The phase 3 success of deramiocel brings immediate change to the lives of late-stage DMD patients who have been in a therapeutic blind spot. The preservation of upper limb function, which allows patients to eat or operate smart devices independently without assistance, is a key change that significantly reduces the daily burden on caregivers. The 91% delay in heart damage progression suggests the potential to prolong patients' lives by preventing the transition to heart failure. Furthermore, it provides a bridge to diversify the treatment market for rare muscle diseases, which has been largely confined to gene therapy, and to expand the indications to other types of cardiomyopathy and degenerative diseases.