ORLANDO, April 2 -- An infusion of autologous bone marrow progenitor cells may improve outcomes for patients who suffer a severe myocardial infarction, a phase I study suggested.
Patients who received the highest doses of enriched CD34+ endothelial progenitor cells in the affected vessel had increased perfusion of the infarct at six months (P=0.01), according to Arshed Quyyumi, M.D., of Emory University in Atlanta.
This is the first study to find a dose response when using enriched progenitor cells to repair damage following an MI severe enough to cause ventricular remodeling, he said at the American College of Cardiology meeting here.
Action Points
- Explain to interested patients that the findings come from a phase I study, which is designed to assess safety and feasibility, not efficacy.
- Note that this study was published as an abstract and presented as a poster at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
Although it is unknown whether this treatment will improve clinical outcomes, he said, a 2007 meta-analysis of similar studies conducted mostly outside the U.S. demonstrated a significant reduction in MIs, and trends toward reductions in death, admissions for heart failure, and repeat revascularization.
Conducted at four centers, the AMR-001 study assigned 16 patients (mean age 53.3) who had an ST-elevation MI to receive target doses of 5, 10, or 15 million CD34+ progenitor cells per milliliter. There were also 15 controls.
All patients received stents, about half of which were drug-eluting.
The cells were harvested about four or five days after the MI with the patients under conscious sedation. A mean of 409 mL of bone marrow was extracted. There was no pain or bleeding associated with the procedure.
The marrow was sent to a lab, where it was processed to select CD34+ endothelial and other progenitor cells. The cells were returned to the hospital 24 to 36 hours later.
The cells were infused into the infarct-related vessel using a balloon catheter seven to 10 days after the MI.
There were no differences between the treated patients and controls in the occurrence of serious adverse events (P=0.46).
There was one death in a patient assigned to receive the dose of 15 million cells per milliliter, but it was determined to be unrelated to treatment. When the patient went to the cath lab to receive the cell infusion it was discovered that his artery had re-occluded and required restenting. He died soon after of progressive coronary artery disease.
"The whole process was safe and feasible," Dr. Quyyumi said.
He and his colleagues also looked at perfusion using single photon emission computed tomography (SPECT) and functional outcomes using MRI.
Compared with the controls and the patients who received the lowest dose, patients who received the two highest doses had significantly improved resting perfusion of the area around the infarct (P=0.01).
There were nonsignificant trends toward improvements in end-systolic volume, ejection fraction, and infarct size.
Dr. Quyyumi said the FDA has approved a phase II study, which could start later this year. The plan is to infuse only patients from whom 10 million cells per milliliter or more can be harvested.
| Dr. Quyyumi made no financial disclosures. The chairman of Amorcyte, which is developing this approach, was listed as an author on the study. Another study author is employed by Progenitor Cell Therapy, whose technology was used to select the CD34+ cell. |
Primary Source
American College of Cardiology
Source Reference: Quyyumi A, et al "CD34+ cell infusion after ST-elevation myocardial infarction is associated with improved perfusion" ACC 2009; Abstract 1032-139.