Castle Biosciences' Mesothelioma Molecular Test Accurately Stratifies Survival Risk Under Surgical and Non-Surgical Treatment Plans

TORONTO, April 29, 2014 /PRNewswire/ -- Castle Biosciences Inc. announced that data from two validation studies of its DecisionDx-Mesothelioma molecular test were presented at the American Association for Thoracic Surgery 94^th Annual Meeting. According to the data, the test accurately predicted survival in metastatic pleural mesothelioma (MPM) patients based on the gene expression profile signature of their tumor combined with clinical characteristics. 

The results were reviewed during an oral presentation by Dr. Assunta De Rienzo, Ph.D., co-Director of the Thoracic Surgery Laboratory in the Department of Surgery, Thoracic Division, Brigham and Women's Hospital. The test, which combines the results of a gene expression profile with lymph node status and histology subtypes, had previously been validated in a prospective, single-center study. Following licensing of the technology from Brigham and Women's Hospital, CAP-accredited and CLIA-certified laboratory protocols were developed and validated in formalin-fixed paraffin embedded (FFPE) tissue. These results were from a second clinical validation study, which was conducted using a prospectively-planned, multi-center cohort study in conjunction with the National Mesothelioma Virtual Tissue Bank.

"The research shows that in the appropriate clinical context, this test provides possible stratification options resulting in either a good prognosis or a poor prognosis," said Raphael Bueno, MD, Associate Chief, Thoracic Surgery, Vice Chair of Surgery for Cancer and Translational Research, Brigham and Women's Hospital, Professor of Surgery, Harvard Medical School, and co-inventor of the technology licensed by the company. "When reviewed with an experienced physician, the test results allow the patient to decide whether to seek a specialized center for surgical consultation or alternatively consider other forms of less aggressive therapy."

Clinical Validation Study Details 
The DecisionDx-Mesothelioma test reports the gene expression profile in combination with histology subtype and lymph node status to predict "low risk," "intermediate risk" or "high risk" of tumor recurrence for patients with MPM. In the clinical validation cohort consisting of 85 MPM cases, Kaplan-Meier survival analysis was performed to assess prognostic outcome for each patient group. Median overall survival was 52 months in the low risk group (n=27), 14 months in the intermediate risk group (n=56), and 1 month in the high risk group (n=2) (p=0.015). Similar to previous clinical validation findings, in this study the DecisionDx-Mesothelioma test was found to be an independent predictor of survival compared to clinical characteristics alone.

Technical Validation Study Details 
Following development of technical protocols under CAP-accredited, CLIA certified laboratory methodology using FFPE tissue, the test was compared to the research method in paired FFPE/fresh frozen samples in 77 patients. The two methods showed concordance in 91% (70/77) of the patients studied, with no technical failures, when used in combination with clinical factors and lymph node status.

"Mesothelioma is a challenging disease for the patient, their family and the treating physician," said Derek Maetzold, President and Chief Executive Officer of Castle Biosciences. "Today mesothelioma patients are often treated similarly, even though we know some will progress much more rapidly than others. The ability to distinguish between low and high risk patients is important for physicians, patients and their families to be able to select those treatment plans that may extend survival while maintaining a high quality of life."

Castle is currently making DecisionDx-Mesothelioma available to physicians as part of an early access program.

About Mesothelioma 
Mesothelioma is a rare cancer with about 3,000 new diagnoses in the United States per year. Though anyone can develop mesothelioma, it is most common in men of Caucasian and Hispanic/Latino descent over the age of 65 and those who have been exposed to asbestos, usually through the workplace. The disease originates in the mesothelium, or the protective lining that covers many internal organs. About 75% of mesotheliomas begin in the lining of the lungs (pleural mesothelioma).  Although the disease can be treated in some patients using highly invasive surgical procedures, there is currently no cure for mesothelioma.

About Castle Biosciences  
Castle Biosciences is a molecular diagnostics and prognostics company dedicated to helping patients and their physicians make the best possible decisions about their treatment and follow-up care based on the individual molecular signature of their tumor. The Company currently offers prognostic tests for patients with rare cancers including uveal and cutaneous melanoma, thymoma, esophageal and brain cancers. More information can be found at www.castlebiosciences.com. 

SOURCE Castle Biosciences Inc.