The Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis Pilot Study (The POSEIDON-Pilot Study)

A Phase I/II, Randomized Pilot Study of the Comparative Safety and Efficacy of Transendocardial Injection of Autologous Mesenchymal Stem Cells Versus Allogeneic Mesenchymal Stem Cells in Patients With Chronic Ischemic Left Ventricular Dysfunction Secondary to Myocardial Infarction

The technique of transplanting progenitor cells into a region of damaged myocardium, termed cellular cardiomyoplasty, is a potentially new therapeutic modality designed to replace or repair necrotic, scarred, or dysfunctional myocardium. Ideally, graft cells should be readily available, easy to culture to ensure adequate quantities for transplantation, and able to survive in host myocardium; often a hostile environment of limited blood supply and immunorejection. Whether effective cellular regenerative strategies require that administered cells differentiate into adult cardiomyocytes and couple electromechanically with the surrounding myocardium is increasingly controversial, and recent evidence suggests that this may not be required for effective cardiac repair. Most importantly, transplantation of graft cells should improve cardiac function and prevent adverse ventricular remodeling. To date, a number of candidate cells have been transplanted in experimental models, including fetal and neonatal cardiomyocytes, embryonic stem cell-derived myocytes, tissue engineered contractile grafts, skeletal myoblasts, several cell types derived from adult bone marrow, and cardiac precursors residing within the heart itself. There has been substantial clinical development in the use of whole bone marrow and skeletal myoblast preparations in studies enrolling both post-infarction patients, and patients with chronic ischemic left ventricular dysfunction and heart failure. The effects of bone-marrow derived mesenchymal stem cells (MSCs) have also been studied clinically.

Currently, bone marrow or bone marrow-derived cells represent highly promising modality for cardiac repair. The totality of evidence from trials investigating autologous whole bone marrow infusions into patients following myocardial infarction supports the safety of this approach. In terms of efficacy, increases in ejection fraction are reported in the majority of the trials.

Chronic ischemic left ventricular dysfunction resulting from heart disease is a common and problematic condition; definitive therapy in the form of heart transplantation is available to only a tiny minority of eligible patients. Cellular cardiomyoplasty for chronic heart failure has been studied less than for acute MI, but represents a potentially important alternative for this disease.

Inclusion Criteria:

• Diagnosis of chronic ischemic left ventricular dysfunction secondary to MI.
• Be a candidate for cardiac catheterization.
• Been treated with appropriate maximal medical therapy for heart failure or post-infarction left ventricular dysfunction.
• Ejection fraction between 20% and 50%.
• Able to perform a metabolic stress test.

Exclusion Criteria:

• Baseline glomerular filtration rate <50 ml/min/1.73m2.
• Presence of a mechanical aortic valve or heart constrictive device.
• Documented presence of aortic stenosis (aortic stenosis graded as ≥+2 equivalent to an orifice area of 1.5cm2 or less).
• Documented presence of moderate to severe aortic insufficiency (echocardio- graphic assessment of aortic insufficiency graded as ≥+2).
• Evidence of a life-threatening arrhythmia (nonsustained ventricular tachycardia ≥20 consecutive beats or complete heart block) or QTc interval >550 ms on screening ECG. In addition; patients with sustained or a short run of ventricular tachycardia on ECG or 48 hour Ambulatory ECG during the screening period will be removed from the protocol.
• Documented unstable angina.
• AICD firing in the past 60 days prior to the procedure.
• Be eligible for or require coronary artery revascularization.
• Have a hematologic abnormality as evidenced by hematocrit < 25%, white blood cell < 2,500/ul or platelet values < 100,000/ul without another explanation.
• Have liver dysfunction, as evidenced by enzymes (ALT and AST) greater than three times the ULN.
• Have a coagulopathy condition = (INR > 1.3) not due to a reversible cause.
• Known, serious radiographic contrast allergy.
• Known allergies to penicillin or streptomycin.
• Organ transplant recipient.
• Clinical history of malignancy within 5 years (i.e., patients with prior malignancy must be disease free for 5 years), except curatively-treated basal cell carcinoma, squamous cell carcinoma, or cervical carcinoma.
• Non-cardiac condition that limits lifespan to < 1 year.
• On chronic therapy with immunosuppressant medication.
• Serum positive for HIV, hepatitis BsAg, or hepatitis C.
• Female patient who is pregnant, nursing, or of child-bearing potential and not using effective birth control.