FDA Disputes Capricor's Phase 3 Efficacy Claims for Duchenne Cell Therapy Deramiocel

Capricor Therapeutics is heading into a July 29 FDA advisory committee meeting facing a direct disagreement with the agency over whether its Phase 3 HOPE-3 trial of deramiocel, an investigational allogeneic cardiosphere-derived cell therapy for Duchenne muscular dystrophy (DMD) cardiomyopathy, actually met its efficacy endpoints.¹ In December 2025, Capricor announced that HOPE-3 hit both its primary and secondary endpoints.¹ In briefing documents released ahead of the advisory committee meeting, however, FDA reviewers wrote that the study "did not meet its pre-specified primary and secondary efficacy endpoints, showing no statistically significant difference between deramiocel and placebo at 12 months."¹

The disagreement centers on which version of the trial's statistical analysis plan (SAP) should govern the results. FDA reviewers noted that after the randomized, double-blind portion of the trial was completed, and during the open-label extension period in which all patients received the cell therapy, changes were made to the SAP, producing at least two additional versions beyond the original.¹ The agency also raised questions about the effectiveness of blinding in HOPE-3, citing a distinctive adverse event profile, including hypersensitivity reactions, that differed between treatment groups.¹

How has Capricor responded?

Capricor issued its own statement the same day the FDA's briefing documents were released, disputing the agency's characterization of the data. Linda Marbán, PhD, chief executive officer of Capricor Therapeutics, said, "Capricor has engaged fully and transparently with the FDA throughout the review process for our Biologics License Application for Deramiocel and has been responsive to every request from the FDA. Our results are governed by the final analysis plan, SAP version 3.0, which was finalized prior to unblinding. It is critical to understand that the post-hoc analyses in the FDA's briefing materials rely on SAP version 1.1, an unsigned incomplete internal draft which became obsolete with the addition of cohort B and did not include content specifically requested by FDA. The Phase 3 HOPE-3 results demonstrate a statistically significant benefit on the primary endpoint, PUL 2.0, with supportive benefits in cardiac function, and we believe Deramiocel offers a meaningful treatment option for boys and young men living with Duchenne, who continue to face a significant unmet medical need."²

How does deramiocel work, and what is its regulatory history?

Deramiocel is an allogeneic, cardiac-derived cell therapy that Capricor says has been shown in clinical studies to preserve cardiac and skeletal muscle function in patients with DMD, a rare genetic condition caused by a defective gene that results in an absence of dystrophin, a protein that helps keep muscle cells intact.² ³ The FDA initially issued a complete response letter for deramiocel's biologics license application in July 2025, concluding the submission lacked substantial evidence of effectiveness. The agency subsequently agreed to continue reviewing the application as a Class 2 resubmission based on newly submitted HOPE-3 data, setting a Prescription Drug User Fee Act target action date of August 22, 2026.⁶

This is not the first time an FDA advisory committee has weighed in on a DMD therapy amid contested data. In 2016, the agency approved eteplirsen for DMD despite opposition from its own advisory committee, a decision that drew criticism at the time but also reflected intense support from patient advocacy communities given the severity and rarity of the disease.⁴ DMD gene and cell therapies have continued to face significant regulatory scrutiny in the years since; the FDA has separately investigated safety concerns tied to Sarepta Therapeutics' gene therapy Elevidys, including a temporary shipment halt following patient deaths.⁵

Why does this dispute matter beyond deramiocel itself?

DMD remains a rare, progressive, and ultimately fatal disease with limited treatment options. Capricor's stock declined sharply following the FDA's briefing document release.⁷

What happens next?

The FDA's Cellular, Tissue, and Gene Therapies Advisory Committee is scheduled to meet on July 29, 2026, to discuss Capricor's BLA for deramiocel, with the agency's target action date currently set for August 22, 2026.¹ Capricor said it has posted a portion of its presentation slides to its investor website ahead of the meeting to frame its position for stakeholders.² The advisory committee's recommendation, and the FDA's ultimate decision on which statistical analysis plan should govern the review, will determine whether deramiocel becomes the first cell therapy approved specifically for DMD-associated cardiomyopathy.

References

1. UPDATE: FDA Disputes Capricor's Claims of Phase 3 Success for DMD Cell Therapy. BioSpace. July 27, 2026. Accessed July 28, 2026. https://www.biospace.com/drug-development/fda-disputes-capricors-claims-of-phase-3-success-for-dmd-cell-therapy
2. Capricor Therapeutics. Capricor Comments on Briefing Materials Ahead of July 29 FDA Advisory Committee Meeting for Deramiocel. Press Release, GlobeNewswire, July 27, 2026. Accessed July 28, 2026. https://www.globenewswire.com/news-release/2026/07/27/3333710/0/en/Capricor-Comments-on-Briefing-Materials-Ahead-of-July-29-FDA-Advisory-Committee-Meeting-for-Deramiocel.html
3. FDA Expands Approval of Sarepta's Duchenne Muscular Dystrophy Gene Therapy. BioPharm International. June 25, 2024. Accessed July 28, 2026. Available at: biopharminternational.com/view/fda-expands-approval-of-sarepta-s-duchenne-muscular-dystrophy-gene-therapy
4. FDA Advisory Committees Under Scrutiny. BioPharm International. June 22, 2021. Accessed July 28, 2026. Available at: https://www.biopharminternational.com/view/fda-advisory-committees-under-scrutiny
5. FDA Investigates Pediatric Elevidys Death: 5 Things to Know. BioPharm International. July 28, 2025. Accessed July 28, 2026. Available at: https://www.biopharminternational.com/view/fda-investigates-pediatric-elevidys-death-5-things-to-know
6. Capricor's DMD Cardiomyopathy Cell Therapy Deramiocel Back Under Review by FDA. NeurologyLive. March 10, 2026. Accessed July 28, 2026. Available at: https://www.neurologylive.com/view/capricor-dmd-cardiomyopathy-cell-therapy-deramiocel-back-under-review-fda
7. Capricor Plunges on FDA AdCom Briefing Doc for Duchenne Treatment. Seeking Alpha. July 27, 2026. https://seekingalpha.com/news/4618810-capricor-plunges-fda-adcom-briefing-doc-duchenne-treatment