For First Time, Study Proves Stem Cell Therapy for Heart Patients Is Safe
An FDA-approved clinical trial is the first to show that treating patients with adult stem cells after a heart attack is safe and that it appears to repair damaged heart tissue. Results of the study are published in the December 8 issue of the Journal of the American College of Cardiology.
The trial, lead by Joshua M. Hare, M.D., director of the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine, found that the stem cell-treated patients had lower rates of side effects, such as cardiac arrhythmias. Moreover, "they had significant improvements in heart, lung and global function," Hare explained. "Echocardiography showed improved heart function, particularly in those patients with large amounts of cardiac damage."
Right now, there is no method to repair the damaged cardiac tissue in the estimated 700,000 Americans who will suffer a heart attack each year.
The Phase I trial was designed to determine the safety and efficacy of administering Prochymal, an intravenous formulation of adult mesenchymal stem cells, in patients within days of a heart attack to lessen damage to the heart muscle. Fifty-three patients who had suffered a heart attack within one to ten days, were randomized to one of three doses of stem cells, and each dose was compared with placebo. Researchers evaluated treatment-related serious adverse affects after six months and used echocardiography to assess efficacy.
The study should allay some of the controversy surrounding clinical stem cell research for heart disease. "Many have argued that it's premature to test stem cells in patients" Hare says. "This trial proves the value of rigorous and monitored clinical testing. It lays the foundation for a brand new cell-based therapy for the human heart."
Osiris Therapeutics of Columbia, Maryland sponsored the trial, which took place at 10 medical centers in the U.S. starting in February 2005. The results were first presented at the American College of Cardiology's Innovation in Intervention: i2Summit held in March 2007.
The Osiris trial "serves as a benchmark for us to move forward with this stem cell line," says Hare. Mesenchymal stem cells have a number of advantages as a cell-based therapy: they can be taken from genetically distinct donors, are easy to prepare, and have a tendency to collect within injured areas.
In the last couple of years, Hare has initiated a number of key clinical trials at the University of Miami and published more critical findings in mesenchymal stem cell research. In April 2008, Hare began a Phase I randomized, placebo-controlled trial injecting mesenchymal stem cells into heart attack patients during open-heart surgery. Later that year, another trial began, this one using a novel catheter device to inject stem cells, opening the possibility of stem cell therapy to more patients. Recently, Hare and his team initiated a study comparing autologous with allogenic stem cells (from a donor).
It's "very exciting to see where this line of research will take us. With each study, we hope to learn more about the possibilities of using adult stem cell therapies to treat cardiac patients," says Hare, who is the Louis Lemberg Professor of Medicine at the University of Miami.