Could Regenerative Medicine Reverse Damage After a Heart Attack?
A cell therapy approach improved patients' quality of life after a heart attack; plans for Phase 3 trials are underway.
Chest pain, shortness of breath, and a feeling of impending doom are hallmark signs of a heart attack, or myocardial infarction (MI), that clinicians are trained to recognize.
With the right collection of symptoms and medical signs, healthcare professionals can quickly trigger well-established protocols, allowing many patients who might not have survived decades ago to do so.
But while advances in medical interventions have improved survival in the emergency department, they haven’t necessarily translated into restoring that person’s ability to live once they return home.
With more individuals than ever surviving the acute phase of an MI, Matthieu de Kalbermatten, chief executive officer of CellProthera, believes the focus should be on regeneration—not just rehabilitation. In an interview with Technology Networks, he shared how ProtheraCytes®, an autologous CD34+ cell therapy, aims not just to manage symptoms but to restore cardiac function at a biological level.
The role of CD34+ cell therapy post-MI
Can you outline the scientific basis for ProtheraCytes as a regenerative approach following MI?
De Kalbermatten set the scene by putting the therapeutic approach into context: “ProtheraCytes are an autologous cell therapy composed of highly purified and ex vivo-expanded CD34+ stem/progenitor cells.”
CD34+ stem/progenitor cells
The therapeutic cells are a combined population of hematopoietic stem cells and early progenitor cells that contribute to two key processes:
- Hematopoiesis: The creation of all blood and immune cells.
- Angiogenesis: The formation of new blood vessels.
“These mechanisms are particularly relevant in patients with large MI, whose myocardium has lost contractility and are at high risk of developing adverse ventricular remodeling and subsequent heart failure,” noted de Kalbermatten.
Heart failure after MI occurs in ~20–30% patients within the first 12 months.
A heart attack occurs when blood flow to the heart is insufficient. Whatever the underlying reason—atherosclerotic plaques, embolism, spasm, or dissection—if blood supply and oxygen are not restored quickly, cardiac tissue becomes irreversibly damaged.
To compensate for lost function, the heart undergoes remodeling: scars form, chamber walls stretch, and muscles thicken. Although seemingly intuitive, this process is generally maladaptive, as chambers over-dilate and muscles hypertrophy, leaving the heart unable to meet the body’s demands.
At this point, heart failure has occurred. This debilitating outcome is exactly what de Kalbermatten wants to avoid, and the feasibility and safety of CellProthera’s approach were tested in the Phase 1/2b EXCELLENT trial.
The EXCELLENT Phase 1/2b trial
The study enrolled 77 post-MI patients who received ProtheraCytes plus standard-of-care (SoC) or SoC alone, in a 3:1 ratio. The analysis included 31 patients in the treatment group and 12 in the control group. In treated patients, blood samples were collected after CD34+ mobilization with lenograstim, and patient CD34+ cells were expanded for nine days. Following expansion, the cells were directly delivered to damaged heart tissue.
Treated patients showed statistically significant improvements in several quality-of-life domains, including physical functioning, vitality, and pain.
Biological improvements were observed in the treatment group, including reductions in N-terminal pro-B-type natriuretic peptide (NT-proBNP)—a biomarker used in the diagnosis of heart failure—and indicators of anti-remodeling effects, though the clinical significance of these changes remains to be established in subsequent trials.
Rationale behind CD34+ cell therapy for heart regeneration:
- CD34+ cells drive vascular regeneration and repair.
- Early clinical data indicate the therapy is feasible and safe.
- The approach targets the root mechanisms of heart failure development and progression.
Overcoming cell therapy bottlenecks with scalable platforms
How have longstanding cell therapy challenges, such as manufacturing and logistics, been addressed?
Historically, challenges in cell therapy manufacturing, logistical complexity, and high costs have been significant barriers to uptake. CellProthera addressed these challenges by prioritizing process standardization early in development.
They developed a proprietary platform that combines the StemXpand® device and the StemPack® kit to automate cell expansion.
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“This platform ensures a consistent expansion of CD34+ cells, reducing batch-to-batch variability and enabling industrial scale-out, i.e., the production of several batches in parallel,” explained de Kalbermatten.
By developing Good Manufacturing Practice (GMP)-compliant production technology alongside their novel therapy, the team has ensured that patient access and affordability are central to the innovation, rather than an afterthought.
Operational breakthroughs include:
- Automated, GMP-compliant expansion technology enables consistent therapy production across sites, supporting access.
- Parallel batch production enables scalability.
The heart of the matter: Delivering cell therapy to the myocardium
Can you describe the catheter-based delivery of ProtheraCytes?
How and where a therapy is delivered is a defining factor in its success, particularly in regenerative medicine.
“ProtheraCytes are delivered through a catheter-based, transendocardial injection procedure which administers expanded CD34+ cells directly into the damaged myocardium,” explained de Kalbermatten.
Transendocardial injection
A minimally invasive procedure where therapeutic agents are delivered directly into the heart wall, using a catheter that has been inserted into an artery (typically the femoral artery next to the groin).
“CellProthera’s catheter enables operators to inject cells precisely and accurately around the scar of the heart,” he continued. This precision is essential for targeting tissue that can benefit most from regenerative signals.
De Kalbermatten explained that catheter delivery also offers logistical advantages, including their long shelf life: “It is very similar to the distribution of medical products used in interventional cardiology, such as stents. Catheters can be stored in cardiology centers in advance.”
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Advantages of catheter-based cell therapy delivery:
- Direct delivery provides precise therapeutic targeting.
- Established interventional cardiology workflows ease adoption.
The trade-offs of taking heart failure cell therapy worldwide
What advantages does a geographically diverse Phase 3 program offer, and what difficulties does this introduce?
CellProthera’s Phase 3 strategy leverages a global, multicenter design to strengthen clinical and regulatory outcomes. They hope to recruit across sites in the United States, Europe, and Asia.
De Kalbermatten highlighted the advantages of this approach: faster patient recruitment, broader generalizability of results, early alignment with multiple regulators, and operational experience across various clinical infrastructures.
However, these benefits don’t come without cost.
“Multicontinental trials also introduce significant complexities,” he noted. “Geographic diversity enhances scientific and regulatory strength but demands meticulous planning, harmonized procedures, and robust logistical control.”
Strategic trade-offs of global Phase 3 trials include:
- Improved generalizability and faster recruitment vs increased operational complexity.
- Global regulator engagement vs fragmented compliance requirements.
- Scalable infrastructure vs high cost and coordination requirements.
Setting the bar for success in regenerative cardiac medicine
How have results from earlier stages informed the Phase 3 program, and which outcomes will be most closely watched?
Early insights have directly informed Phase 3 design, especially in selecting the primary endpoint.
While quality-of-life scoring was a valuable indicator of patient outcomes, quantitative evidence from biomarkers and imaging will be required to demonstrate clinical efficacy.
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“The biological signals of efficacy observed in Phase 1/2b, such as left ventricular volume and NT-proBNP reduction, have been incorporated into the composite primary endpoint of Phase 3,” commented de Kalbermatten. Clinical outcomes, including heart-failure-related hospitalization and mortality, will also be closely watched.
Left ventricular volume and NT-proBNP
Left ventricular volume reflects the size of the heart’s main pumping chamber. Increased volume post-MI indicates adverse remodeling. Reducing or stabilizing this metric suggests that therapy may be preserving cardiac structure.
NT‑proBNP is a blood biomarker released in response to cardiac stress. Elevated levels are associated with heart failure severity and poor clinical outcomes. A decline in NT‑proBNP is considered a signal of reduced stress.
De Kalbermatten added that the Phase 3 trial will build on existing safety insights: “Procedural safety is going to be further improved by combining a new catheter technology, enhanced operator training, and more rigorous preprocedural imaging guidance.”
Phase 3 priorities:
- Endpoints will integrate functional biomarkers and imaging data.
- Clinical outcomes such as mortality and hospitalization remain central.
- Enhanced delivery techniques will aim to improve safety and consistency.
Redefining recovery after post-MI with regenerative cardiology
As regenerative medicine advances, therapies such as ProtheraCytes illustrate how biological insight, engineering innovation, and global strategy can converge to address unmet medical needs.
“Overall, ProtheraCytes offers a biologically rational and clinically supported approach designed to protect ischemic myocardium, promote regeneration, and prevent progression to heart failure after MI.”
At a glance:
- Autologous CD34+ cell therapy targets the underlying biology of cardiac injury and remodeling following MI.
- Scalable, automated manufacturing platforms are overcoming historic barriers in cell therapy.
- Global trial design has the potential to accelerate clinical translation and regulatory readiness.
This content includes text that has been created with the assistance of generative AI and has undergone editorial review before publishing. Technology Networks' AI policy can be found here.
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