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    Researchers Identify First-Ever Blood Test to Determine Rejection in Kidney Transplants Without Biopsy

    Amy Weitz, 510-206-1855

    Multi-center clinical trial validates novel gene panel for predicting kidney transplant rejection

    San Francisco, CA, October 29, 2012 – In a significant and promising finding that can establish earlier and better treatment for kidney transplant patients, researchers have discovered the means to determine through a simple blood test whether or not a transplanted kidney has been rejected. This diagnostic blood test can monitor for rejection without performing an invasive biopsy procedure, which is the current standard of care.

    Through a multi-center clinical trial involving blood samples from 236 pediatric and young adult kidney transplant recipients, researchers were able to identify a set of gene biomarkers that were present only in the blood of patients who had had acute transplant rejection proven by a biopsy. This study is the largest coordinated effort of its kind and the only biomarker transplant study to be funded and independently validated by the National Institutes of Health.

    “We are really excited about the discovery of this new test that can really benefit patients and provide valuable and actionable information to the doctor,” said Minnie Sarwal, MD, FRCP, PhD, Professor of Pediatrics and Director of the BIOMARC Program for Personalized Medicine at the California Pacific Medical Center Research Institute (CPMCRI, a Sutter Health affiliate) and the corresponding author of the study. “This test was validated in patients enrolled from 12 different transplant programs in the US and sets a new standard for proactively monitoring the transplant patient for rejection.”

    “For kidney transplant patients, it’s critical to know as soon as possible if the transplant is being rejected so that we can treat early and reverse injury,” Dr. Sarwal added. “Right now, the only way to determine rejection is through a biopsy, which is invasive, stressful and costly, and is often performed late when there is already substantial damage to the kidney. This novel blood-gene test can identify rejection very early, before much damage to the transplant. This less invasive and simpler way to monitor our patients will give us a better chance of preserving their long-term kidney function.”

    Dr. Sarwal pointed out that kidney transplant patients with apparently normal kidney function may in fact be experiencing rejection of the transplant. Conversely, signs of transplant dysfunction do not always indicate rejection, but rather could signify other problems such as infection or obstruction. The gene-blood test can differentiate rejection from other causes of kidney dysfunction.

    In the multi-center trial researchers analyzed a total of 367 blood samples from the trial participants; of those, 115 were from participants whose biopsy had indicated rejection, 180 were from those who were stable, and 72 were from patients who had had a transplant injury but no rejection. Ultimately, the researchers identified five genes that correlated with samples from patients in the rejection group. The sensitivity and specificity of this blood test was more than 90 percent accurate. The study was published in the October 2012 issue of the American Journal of Transplantation (A Peripheral Blood Diagnostic Test for Acute Rejection in Renal Transplantation, Vol 12, Issue 10, pp 2710-1718).

    Next steps

    “Having a simple way to diagnose transplant rejection – or even possibly predict it ahead of time – can make a vast difference in how we care for our patients,” said Dr. Sarwal. “Our goal is to move forward with a prospective study to further validate the test and provide usable data to physicians, and to include patients of all ages. Given that we have 30,000 kidney patients undergoing transplants each year in the US alone, and there are over 120,000 with a prior kidney transplant in the US, having a diagnostic tool such as this could make a significant impact on the health and care of these individuals.” The team believes they have found a common method to track injury in all organ transplants and are currently working on validating this gene test in blood for determining acute rejection also in heart, intestine and lung transplants.

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