New technology for cardiac transplant patients indicates a patient's risk of organ rejection with a simple blood test. News of this revolutionary testing method will be presented today at the International Society for Heart and Lung Transplantation's (ISHLT) Annual Meeting and Scientific Session in Philadelphia.
This breakthrough in molecular testing is a non-invasive method that translates the complex signals of the immune system's multiple genes and pathways into an objective, actionable score. Along with proactive monitoring of the patient's immune system, physicians can now use this test to identify rejection and tissue damage before it occurs.
Mandeep Mehra, M.D., head of the Division of Cardiology at the University of Maryland School of Medicine, in Baltimore, praises the new development in a symposium held during the ISHLT meeting.
"In the past decade, this is truly one of the most important breakthroughs in the field of heart transplantation," said Mehra. "Now that we have a test based on analysis of the human genome, we can begin to better understand why tissue and organ rejection occurs and use that knowledge to improve individual patient outcomes."
The symposium will highlight AlloMapTM molecular expression testing, which monitors the immune system with non-invasive technology and is currently being used in the management of heart transplant patients. In addition to detecting rejection, AlloMap identifies at-risk patients that biopsy misses, clarifies indeterminate biopsy results, and reduces the need for biopsies altogether.
For patients, molecular testing means less discomfort during the constant monitoring for rejection that is required for prolonged transplant success. Until recently, heart biopsy was the standard method of monitoring for transplant rejection. During this invasive procedure, a bioptome – a wire with small clippers – is inserted into a vein in the patient's neck or groin and threaded through blood vessels into the heart. Small pieces of the heart muscle are clipped off and sent for laboratory evaluation for microscopic evidence of rejection.
The most common cause of death in the first year after transplantation is acute cardiac rejection; the patient's immune system attacks the heart as if it were a foreign object until the organ stops functioning properly. As a result of this risk, patients generally endure multiple cardiac biopsies, as many as 12 – sometimes more – in their first year after a transplant; periodic biopsies may continue for years. Unfortunately for many patients, biopsy procedures carry significant risk of adverse effects and they detect rejection only after damage to the heart has occurred.
With 4,500 cardiac transplants performed worldwide each year, it is believed that the new molecular testing procedures will alleviate the need for tens of thousands of biopsies and the patient discomfort that accompanies the biopsy.
The clinical value of AlloMap testing was demonstrated in a landmark multi-center, prospective study known as the Cardiac Allograft Rejection Gene Expression Observational (CARGO) study, which was presented at ISHLT's 2004 meeting.
During today's symposium, Howard Eisen, M.D., will review the results of the CARGO study and discuss the clinical implementation of molecular testing protocols at Drexel University College of Medicine (Hahnemann Medical Center) in Philadelphia. Hannah Valantine, M.D., will review clinical uses for AlloMap testing and discuss specific cases where the test has been used clinically at Stanford University Medical Center.
AlloMap is also undergoing clinical trials for lung transplant patients. Shaf Keshavjee, M.D., Toronto General Hospital, Canada, will provide an update on LARGO, an international, multi-center clinical trial that studies the ability of AlloMap to improve clinical management of lung transplant recipients. He will also discuss his work on molecular evaluations of donor lungs.