FDA Extends Deramiocel Review for Duchenne Muscular Dystrophy

The FDA has extended the Prescription Drug User Fee Act (PDUFA) target action date for Capricor Therapeutics' deramiocel, an investigational cell therapy for Duchenne muscular dystrophy (DMD), from August 22 to November 22, 2026.¹ The 3-month extension follows the agency's acceptance of additional phase 3 HOPE-3 (NCT05126758) data as a major amendment to the biologics license application (BLA).²

The amendment includes 24-month open-label extension findings and additional robustness analyses from HOPE-3.¹ Capricor submitted the information after a July 2026 FDA advisory committee meeting and asked the agency to consider a refined proposed indication centered on preservation of upper limb function, the trial's primary end point.¹ The FDA's Center for Biologics Evaluation and Research accepted the amendment for review and classified it as major, prompting the revised action date, and according to Capricor, the agency cited the substantial unmet need associated with DMD.¹

HOPE-3 met its primary and key secondary end points

HOPE-3 enrolled 106 boys and young men with DMD, most nonambulatory, at a mean age of approximately 15 years; more than 75% had a clinical diagnosis of cardiomyopathy, and roughly 90% were already receiving cardiac medications at baseline.² Participants were randomized in double-blind fashion to intravenous deramiocel, 150 million cells, or placebo every 3 months for 12 months.²

The trial met its primary end point, a 54% slowing of decline on the Performance of Upper Limb, version 2.0 (PUL v2.0), in the intention-to-treat population (n = 105; P = .029), and its key secondary end point, a 91% slowing of decline in left ventricular ejection fraction (LVEF) by centrally read cardiac MRI (n = 83; P = .041).² The most frequently reported adverse events were hypersensitivity reactions, managed prospectively with glucocorticoid and H1/H2-blocker pretreatment, and no unexpected safety signals emerged in extended follow-up of the earlier HOPE-2 cohort.²

Regulatory path has included a complete response letter and a negative advisory committee vote

Capricor's BLA was accepted for review in March 2025 under a PDUFA date of August 31, 2025, but the FDA issued a complete response letter in July 2025, citing insufficient evidence of effectiveness and unresolved chemistry, manufacturing, and controls elements.³ After Capricor incorporated the completed HOPE-3 dataset into a resubmission, the agency designated it a class 2 review with an August 22, 2026, PDUFA date.³

An FDA advisory committee voted 9 to 3 against recommending approval on July 29, 2026, with reviewers and several panelists questioning revisions Capricor made to the trial's statistical analysis plan after randomization and expressing skepticism that LVEF functions as a validated surrogate of clinical benefit in this population; the panel also flagged a signal of increased left ventricular volume warranting further scrutiny.⁴ Company representatives and patient advocates argued the totality of evidence, particularly the upper-limb functional data, combined with the absence of any alternative treatment, supported approval despite the panel's nonbinding recommendation.⁴

"With an additional year of follow-up from HOPE-3, we now have one of the most extensive clinical datasets evaluating upper limb function in Duchenne," Linda Marbán, PhD, chief executive officer of Capricor, said in a statement.¹ Marbán said HOPE-3 met its primary end point, demonstrating a statistically significant benefit in upper limb function, and that the additional open-label data and further analyses included in the amendment strengthen the evidence supporting a refined proposed indication, adding that the company appreciates the FDA's continued engagement and looks forward to working constructively with the agency as it completes its review.¹

Deramiocel consists of allogeneic cardiosphere-derived cells that exert immunomodulatory, antifibrotic, and regenerative paracrine effects on injured myocardium and skeletal muscle.¹ The candidate has previously received US orphan drug, regenerative medicine advanced therapy, and rare pediatric disease designations, as well as orphan drug and advanced therapy medicinal product designations in Europe.¹ DMD is an X-linked disorder caused by the absence of functional dystrophin, characterized by progressive skeletal, respiratory, and cardiac muscle degeneration; Capricor estimated approximately 15,000 people in the United States have DMD, predominantly boys, and the disease remains incurable with limited treatment options.¹

Frequently Asked Questions

• What is deramiocel being developed for?
  Deramiocel is an investigational allogeneic cardiosphere-derived cell therapy being developed by Capricor Therapeutics to treat Duchenne muscular dystrophy, with a proposed indication focused on preservation of upper limb function.
• What were the key results of the HOPE-3 trial?
  HOPE-3 met its primary end point, a 54% slowing of decline on PUL v2.0 (P = .029), and its key secondary end point, a 91% slowing of decline in LVEF (P = .041), compared with placebo.
• Why did the FDA extend its review of deramiocel?
  The FDA extended the PDUFA date to November 22, 2026, after accepting a major BLA amendment containing 24-month open-label extension data and additional analyses from HOPE-3.

References

1. Capricor Therapeutics announces extension of PDUFA target action date as FDA continues review of deramiocel BLA. Capricor Therapeutics. Published August 24, 2026. Accessed August 24, 2026. https://www.capricor.com/investors/news-events/press-releases/detail/354/capricor-therapeutics-announces-extension-of-pdufa-target

2. McDonald CM, et al. Deramiocel heart-derived cellular therapy in advanced Duchenne muscular dystrophy (HOPE-3): a phase 3, randomised, double-blind, placebo-controlled trial. Lancet. Published online July 29, 2026.

3. Capricor Therapeutics announces establishment of new PDUFA date for Deramiocel BLA. News release. Capricor Therapeutics. Published March 10, 2026. Accessed August 24, 2026. https://www.capricor.com/investors/news-events/press-releases/detail/338/capricor-therapeutics-announces-establishment-of-new-pdufa

4. Cellular, Tissue, and Gene Therapies Advisory Committee; Notice of Meeting; Establishment of a Public Docket. Federal Register. Published June 29, 2026. Accessed August 24, 2026. https://www.federalregister.gov/documents/2026/06/29/2026-13096/cellular-tissue-and-gene-therapies-advisory-committee-notice-of-meeting-establishment-of-a-public