Dr Michael TaylorMichael Taylor, MD, PhD
The results of Halt Cardiomyopathy Progression (HOPE)-Duchenne, a recently published phase 1/2 trial of intracoronary allogeneic cardiosphere-derived cells (CAP-1002), demonstrated improvement in cardiac muscle function and reduction in myocardium scarring that were statistically significant, and sustained improvement of skeletal muscle functions in patients in advanced stages of Duchenne muscular dystrophy.

Investigators concluded that the therapy appears safe and demonstrates signals of efficacy on both cardiac and upper limb function for up to 12 months, warranting future research of Duchenne muscular dystrophy cardiac and skeletal myopathies.  

“CAP-1002 is the only therapy so far that has shown reduction in myocardium scar and improvement of localized cardiac function in late stage Duchenne associated cardiomyopathy,” Michael Taylor, MD, PhD, the corresponding author, Director of Cardiac MR research at Children’s Healthcare of Atlanta, said in a statement.1 “These findings suggest that CAP-1002 could be an option for older patients who have scarring in the heart as a result of the underlying disease. As many of these patients are in later stages of the disease, the improvement in upper limb strength is important in order to maintain independence.”

The study assessed the feasibility, safety, and efficacy of CAP-1002 in 25 male participants ≥12 years old with a documented genetic diagnosis of Duchenne muscular dystrophy and substantial myocardial fibrosis in ≥4 left ventricular segments—about 68% of participants were wheelchair-dependent at baseline. Participants could not have a left ventricular ejection fraction, ≤35% were required to be receiving evidence-based medical care for >3 months and systemic glucocorticoids for >6 months before screening, and be candidates for cardiac catheterization.

During the 12-month trial, participants were randomized 1:1 to receive either 1 global intracoronary infusion of CAP-1002 plus usual care (n=13) or standard of care alone (n=12). Those randomized to CAP-1002 underwent infusion on study day 0 to receive a single maximum dose of 25 million cells delivered to each major coronary artery with a Terumo Finecross MG catheter, for an intended total dose of 75 million cells per patient. All study participants assigned to receive CAP-1002 completed the infusion, with 12 of 13 participants receiving the full intended dose of 75 million cells.

The primary outcome measure included the change in the mid-level dimension of the Performance of the Upper Limb (PUL) test at month 12, while secondary outcomes included the change in the mid-level dimension of the PUL test at months 3, 6, and 9, and the change in the regional systolic left ventricular wall thickening assessed by cardiac MRI at months 6 and 12.

In comparison to baseline, at 12 months MRI revealed a significant scar size reduction and improvement in inferior wall systolic thickening in the intervention arm. Participants receiving usual care had no relevant changes in cardiac scaring of function. Researchers also found that when utilizing PUL test, the mid-distal PUL improved in 8 of 9 lower functioning CAP-1002 treated participants (P = .007), while the control participants had no improvement in the mid distal PUL tests.

Of all the treatment-emergent adverse effects (TEAE) observed, 94% were reported as mild or moderate in severity; 4 severe TEAEs were reported with 2 in each group. The most common TEAE was atrial fibrillation in 5 of the CAP-1002 treated participants (39%) and 1 of the controls (8%). The atrial fibrillation episodes were asymptomatic and self-limited and all episodes in CAP-1002-treated participants occurred during cell infusion. There were 5 serious adverse effects that were reported across 4 participants—1 control (8.3%) and 3 CAP-1002-treated participants (23.1%). All serious adverse effects in the CAP-1002 group began on day 0 and resolved within 2 days.

The study provides Class II evidence suggesting that intracoronary CAP-1002 is feasible and appears safe and potentially effective therapy for patients with Duchenne muscular dystrophy and thus future clinical research of repeated administrations of IV-delivered CAP-1002 in a larger, placebo-controlled trial is needed.

The phase 2 HOPE-2 (NCT03406780) placebo-controlled clinical trial is currently ongoing and evaluating the safety and efficacy of repeat intravenous doses of CAP-1002. Non-ambulatory and ambulatory boys and young men who meet the eligibility criteria will be randomized to receive either CAP-1002 or placebo every 3 months for a total of 4 doses during a 12-month period.
REFERENCES
1. Neurology Publishes Study Reporting Significant Improvements in Duchenne Muscular Dystrophy Patients Treated with Capricor’s Novel Cell Therapy [news release]. Los Angeles, Calif.:
Capricor Therapeutics; Jan. 24, 2019. https://globenewswire.com/news-release/2019/01/24/1704750/0/en/Neurology-Publishes-Study-Reporting-Significant-Improvements-in-Duchenne-Muscular-Dystrophy-Patients-Treated-with-Capricor-s-Novel-Cell-Therapy.html. Accessed Jan. 25, 2019.
2. Taylor M, Jeffries J, Byrne B, et al. Cardiac and skeletal muscle effects in the randomized HOPE–Duchenne trial. Neurology. 2019;92(8):e1­–e13.
doi: 10.1212/WNL.0000000000006950.