November 15th, 2011
Hype Aside, Hope for Stem Cell Therapy May Be Emerging from Hibernation
Two small studies of cardiac stem cells for the treatment of heart failure have shown promise, but ABC News, CBS News, and other media outlets are throwing around words like “medical breakthrough” and “heart failure cure.” ABC News correspondent Richard Besser was so enthusiastic that anchor Diane Sawyer commented that she had never seen him “so excited.” The first author of one of the studies, Roberto Bolli, said the work could represent “the biggest advance in cardiology in my lifetime.”
The reality may be somewhat more prosaic. In the first paper, published in the Lancet, Roberto Bolli and colleagues, including senior author Piero Anversa, report on a phase 1 study still in progress in which 16 patients with post-infarction left ventricular (LV) dysfunction received cardiac stem cells (CSCs) harvested during bypass surgery and subsequently expanded. Seven patients served as controls.
In the treatment group, LV ejection fraction (EF) increased from 30.3% to 38.5% some 4 months after infusion. There was no change in LVEF in the control group. At 1 year follow-up among eight patients in the CSC group, the LVEF had increased by 12.3 EF units.
“Although the primary purpose of our phase 1 trial was to assess the safety and feasibility of using this distinct and unique population of cells, the treatment effects are very encouraging and compare favourably with previous trials of bone marrow cells. The present results provide a strong rationale for further studies of CSC treatment in patients with severe heart failure secondary to ischemic cardiomyopathy, who have a poor prognosis,” the authors wrote.
The results “raise new optimism because the study is based on rigorous quality standards and the reported benefits are of an unexpected magnitude,” wrote Gerd Heusch in an accompanying comment. “Of course, we will have to see whether further data will meet the promises of the present study…”
In a second study, presented by Eduardo Marbán at the AHA, 31 patients were randomized on a 2:1 basis to intracoronary infusion of cardiosphere-derived cells (CDCs) or a control arm. CDC therapy was safe, and the investigators found evidence that it reduced scar and increased healthy heart muscle. The results suggested that regeneration of cardiac tissue had taken place. Positive trends suggesting improved EF and end systolic and diastolic volumes were also observed. The results, the authors concluded, suggest that this could be the “first therapeutic modality to shrink scar while regrowing viable, functional tissue.”