University Of Pittsburgh Is Investigating The Potential For Adult Stem Cells To Repair Hearts Damaged By Severe Coronary Artery Disease
Trial involves injecting patient’s own stem cells into areas with poor blood flow
PITTSBURGH, October 9, 2006 — The University of Pittsburgh School of Medicine today announced that it is one of the first medical centers in the country participating in a novel clinical trial to study if a patient’s own stem cells can treat a form of severe coronary artery disease. The University of Pittsburgh plans to enroll 10 to 20 subjects in the study, known officially as the Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia (ACT34-CMI) Trial. The ACTC34-CMI trial is the first human Phase II adult stem cell therapy study in the United States designed to investigate the efficacy, tolerability and safety of blood-derived selected CD34+ stem cells to improve symptoms and clinical outcomes in patients with chronic myocardial ischemia (CMI), a severe form of coronary artery disease.
Myocardial ischemia is a serious heart condition that involves narrowing of the coronary arteries and results in limited blood flow to the heart, affecting hundreds of thousands of new individuals each year. A person who suffers from chronic myocardial ischemia continues to experience insufficient flow of oxygen-rich blood to the heart despite optimum medical intervention.
“This is an exciting challenge for us in that we will be able to build a knowledge base of understanding how heart disease might reverse itself through stem cell therapy,” said Joon Sup Lee, M.D., associate professor of medicine, division of cardiology at the University of Pittsburgh School of Medicine, principal investigator of the Pittsburgh clinical trial site, and clinical director, University of Pittsburgh Medical Center Cardiovascular Institute.
“The patient’s own stem cells are injected directly into the heart muscle by a sophisticated navigation system. UPMC is only one of 15 to 20 centers in the country using this latest generation of cardiac navigation systems, which is known as the NOGA® XP. This system allows us to inject cells into a specific area of the heart muscle using a procedure not much more invasive than a cardiac catheterization. Without such a device, it would require opening the chest wall in a surgical procedure to access the heart muscle,” added Dr. Lee.
ACT34-CMI is a prospective, randomized, double-blind, placebo-controlled study that involves adult patients with severe coronary artery disease who are currently on maximal medical therapy and are not suitable candidates for conventional procedures to improve blood flow to the heart, such as angioplasty, stents or coronary artery bypass surgery.
UPMC is one of 15 to 20 research sites nationwide participating in the study, which is sponsored by the Cellular Therapies business unit of the Baxter Healthcare Corporation. Baxter technology is used to select the patient’s own CD34+ stem cells that are under investigation of this trial.
Phase II Trial Procedure and Enrollment
The first step in the ACT34-CMI trial is to establish the baseline frequency and severity of anginal episodes for all study participants. Next, all patients receive a series of subcutaneous injections (needle shots, typically delivered under the skin in the arm, thigh or abdomen) of a commercially produced protein (granulocyte colony stimulating factor). The protein helps to release blood-forming CD34+ cells from the subject’s bone marrow into the bloodstream.
Then, investigators use a cell separation system, similar to automated systems that are used with people who donate specific blood components such as platelets or red blood cells, to collect from the patient’s bloodstream, an enriched preparation of cells that contain CD34+ stem cells. When this process, known as apheresis, is complete, technologists further process the collected stem cells with Baxter’s ISOLEX 300i Magnetic Cell Selection System, currently approved for use with cancer patients, to select the CD34+ stem cells for use in this investigational therapy.
Encouraging Results from Ongoing Phase I Trial
Douglas Losordo, M.D., chief of cardiovascular research at Caritas St. Elizabeth’s Medical Center in Boston, is the principal investigator of the preceding Phase I trial investigating the injection of autologous CD34+ cells into the hearts of CMI patients. While data from this randomized, multi-center, placebo-controlled, double-blind trial have not been fully analyzed, researchers are encouraged by reports that the therapy appeared to be well-tolerated and no serious adverse events directly related to the stem cell therapy were reported.
According to preliminary anecdotal patient reports, 16 of the 24 total Phase I study subjects reported feeling better with reductions in chest pain and improved exercise capacity during the early stage of the trial. Though not sufficiently powered to demonstrate efficacy, these results led directly to Baxter’s decision to sponsor the Phase II trial. Dr. Losordo also is the lead investigator of the Phase II study.
Coronary Artery Disease and Chronic Myocardial Ischemia
Coronary artery disease is the most common form of heart disease and is the leading cause of death in the United States. This condition occurs when the coronary arteries and the smaller vessels that supply oxygen-rich blood to the heart muscle become narrowed or blocked by plaque deposits or blood clots. Poor blood flow and blood clots starve and injure the heart muscle.
The American Heart Association estimates that every year between 125,000 and 250,000 individuals with coronary artery disease develop chronic myocardial ischemia (CMI), one of the most severe forms of coronary artery disease, which can cause unstable angina, heart attacks and progressive heart failure when adequate blood flow is not restored. CMI develops when the coronary arteries become so diseased that they limit blood flow to the heart and send small blood clots downstream, blocking the small blood vessels in the heart. These blockages can result in a series of mini-heart attacks that, while they may be too small to notice at the time, in aggregate can cause significant long-term damage to the heart muscle and disability to the patient. While cardiologists can restore blood flow in some cases, the heart muscle can be irreversibly damaged, leading to significant disability, progressive heart failure and even death.
The UPMC Cardiovascular Institute (CVI) is a national leader in the treatment of heart disease, education and cardiovascular research. The Institute’s research efforts propel the cutting-edge treatments provided to patients. In addition to practicing cardiology, CVI cardiologists subspecialize in a number of areas, including advanced heart failure, cardiac catheterization, nuclear cardiology, cardiac electrophysiology, preventative and rehabilitative cardiology services, as well as basic science research. CVI also collaborates with a number of community-based primary care physicians to provide patients with world class care close to home.