Bypass Surgery and CD133 Marrow Cell Injection for Treatment of Ischemic Heart Failure

Beginning in 2001, a phase-1 equivalent feasibility and safety evaluation of intramyocardial injection of autologous CD133+ bone marrow cells during elective CABG surgery was conducted at Rostock University. No procedure-related adverse events were observed and there was some improvement of myocardial contractility and perfusion. It was decided to proceed with a controlled efficacy testing, comparing the outcome of standard CABG surgery with that after CABG and CD133+ cell injection. The results of that study indicate that the additional cell injection yields a better left ventricular contractility than CABG alone (LVEF = 47.1±8% vs. 41.3±9% at 6 months). Although this result is encouraging, the trial had several limitations that hamper interpretation of the data. Most notably, no sham-injection of placebo material was performed in the control group, and standard 2D echocardiography served as the only measurement of global LV contractility. A more stringent efficacy testing is needed before large-scale clinical multicenter trials are justified.

Therefore, a prospective, full blinded, randomized, and placebo-controlled trial will be conducted at Deutsches Herzzentrum Berlin Berlin (DHZB), employing current state-of-the art measurement of global and regional LV contractility by cardiac MRI. The following hypothesis will be tested: "Patients who undergo CABG \& CD133+ cell injection do not have a higher LV ejection fraction than patient who undergo CABG alone, measured 6 months after the operation". A power analysis based on the previous trial results indicated that 29 patients per group need to be enrolled so as to reject the null-hypothesis with sufficient statistical power. A total of 60 patients will therefore be enrolled in the study and will be randomized to undergo either CABG surgery and injection of placebo or in conjunction with intramyocardial injection of autologous CD133+ enriched bone marrow cells. Bone marrow will be harvested one day prior to surgery and a CD133-enriched cell product (or placebo) will be prepared on-campus. The following day, bypass surgery will be performed and the study substance will be injected in the border zone of the infarcted myocardium. Random allocation will be performed in the cell production facility, so that neither the patient nor the surgeon nor any of the persons involved in follow-up examinations will know whether the cell product or placebo was administered. The primary outcome parameter (LVEF at 6 months) will be measured by cardiac MRI, and secondary outcome parameters include myocardial perfusion, exercise capacity, and quality-of-life assessment.