Data Validate Benefits and Highlight New Applications for Molecular Testing in Transplant Patients
News Apr 10, 2006
XDx has announced that several leading transplant physicians will present data highlighting what the future may hold for the company's first product, AlloMap™ molecular expression testing, a non-invasive method to detect the absence of acute cellular rejection in heart transplant patients by measuring gene expression in a patients' peripheral blood.
At the International Society for Heart and Lung Transplantation (ISHLT) 26th annual meeting, April 5-8, in Madrid, Spain, data will be presented on future applications for AlloMap testing, including its potential ability to monitor immunosuppression and to predict cardiac allograft vasculopathy in patients, as well as success in determining markers in lung transplantation.
During a symposium that will address the clinical integration of molecular and pathological information, Andreas O. Zuckermann, M.D., Department of Cardiothoracic Surgery, University of Vienna, will present the collective clinical experience with AlloMap testing to date and potential protocols for the best use of the test.
"AlloMap testing has been rapidly adopted by the transplant community since it was launched at ISHLT last year," said Dr. Zuckermann.
"It is being used more and more as a preferred alternative to biopsy with great success in the first year post transplant."
"While we will continue to evaluate all the data when determining recommended guidelines, molecular testing is a significant advancement in cardiac transplantation and improves patients' satisfaction with post-transplant monitoring."
AlloMap testing is currently being used by clinicians in 23 transplant centers nationwide.
The test service was launched for heart transplant patients after development and validation in the CLIA-certified (Clinical Laboratory Improvement Amendments) XDx laboratory in January 2005, and ongoing studies suggest that there may be future applications relating to the long- term management of cardiac transplant patients, as well as use in other transplanted organs.
Studies being presented at ISHLT highlight some of these potential new applications while continuing to validate the current benefits of molecular testing in heart transplant patients.
ISHLT Presentations Highlighting Applications for AlloMap Testing:
- Shaf Keshavjee, M.D., chair of Thoracic Surgery, University of Toronto, will present early results from the Lung Allograft Rejection Gene Expression Observational (LARGO) study.
In this prospective, multi-center international study - the first of its kind to look at the use of gene expression testing in lung transplant patients - Dr. Keshavjee and his team assessed gene expression profiles in the peripheral blood samples of lung transplant patients to: 1) identify immune system pathways important in the process of acute cellular rejection of the lung, and 2) determine how these pathways relate to previous identified genes and pathways associated with acute cellular rejection of the heart.
Early results indicate overlap in pathways mediating heart and lung allograft acute cellular rejection, demonstrating that it is likely that AlloMap testing can be developed successfully for use in monitoring other transplanted organs, specifically the lungs.
- Cardiac allograft vasculopathy (CAV) remains the leading cause of late death in heart transplant recipients. It affects 50 percent or more of transplant recipients five years after their transplant.
In an oral presentation, Mario C. Deng, M.D., director of Cardiac Transplantation Research, Columbia University, will discuss preliminary data evaluating the ability to detect and predict CAV with AlloMap testing.
The early results presented examine gene expression relative to CAV, and indicate that differential expression patterns early after transplantation may identify patients at risk for developing CAV.
ISHLT Presentations Validating AlloMap Testing:
- In a poster presentation, Karen Albright, M.D., from Drexel University College of Medicine will discuss the results of a study evaluating the clinical implementation of molecular testing.
Through the routine clinical use of AlloMap testing in patients at least one-year post cardiac transplant, the study found that molecular testing can identify patients experiencing rejection or graft dysfunction and reduce the number of biopsies for stable patients.
- AlloMap testing monitors the expression of 11 genes in heart transplant patients' peripheral blood cells to determine their risk for rejection, as demonstrated through the Cardiac Allograft Rejection Gene Expression Observational (CARGO) study.
A poster by Adriana Zeevi, Ph.D., Department of Pathology, University of Pittsburgh, demonstrates how the assessment of expression in blood cell sub-types was used to determine the level of these genes reflected in rejection.
The study, which verifies that the 11 genes are specifically associated with acute cellular rejection, also indicates that gene expression patterns in blood cells reflect several different pathways associated with rejection, including T-cell priming, systemic responses to inflammation and the overall state of immunosupression.
Dr. Zeevi will also speak to these findings and the immunology of AlloMap testing during the symposium on April 5.
- Because of the known variability in biopsy interpretation, researchers further examined the relationship between molecular testing and biopsy.
Charles C. Marboe, M.D., professor of Clinical Pathology, Columbia University Medical Center, will present findings that indicate higher gene expression test scores, which represent an increased risk for rejection, are associated with greater agreement among pathologists as to a rejection diagnosis.
However, lower gene expression test scores, which indicate a lower risk for rejection, are associated with increased discordance among pathologists for diagnosing rejection.
"As the studies presented at ISHLT demonstrate, the use of AlloMap testing for heart transplant patients is just the beginning," said Pierre Cassigneul, chief executive officer, XDx.
"Leading researchers and physicians continue to validate the benefits of molecular testing and explore the potential for this technology in other solid organs."
"We are delighted to be at the forefront of these developments in transplant medicine and are proud to see AlloMap testing enhancing the monitoring and management of transplant patients."
For more information about AlloMap testing and the presentations listed above, visit XDx at booth #600 at the ISHLT annual conference.