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After Promising Validation Results, Castle Offers Docs Early Access to Mesothelioma Prognostic Dx


Originally published May 6.

NEW YORK (GenomeWeb) – Castle Biosciences presented data from two validation studies involving its DecisionDx - Mesothelioma molecular test at the American Association for Thoracic Surgery annual meeting.

Using a combination of gene expression profiling and patients’ clinical characteristics, the DecisionDx – Mesothelioma test accurately predicted survival in those with metastatic pleural mesothelioma (MPM), the studies showed. Based on these results, Castle announced it would make DecisionDx – Mesothelioma available to doctors through an early access program.

Castle Biosciences licensed the technology for the test from Brigham and Women’s Hospital, and clinically and technically validated the performance characteristics of the test in these studies. Results from the two trials were presented at the conference by Assunta De Rienzo, co-director of the thoracic surgery lab at Brigham and Women’s.

The clinical validation study, which Castle conducted in collaboration with the National Mesothelioma Virtual Tissue Bank, involved 85 MPM cases. Researchers compared how well the DecisionDx – Mesothelioma assay was able to gauge survival in these patients. Those patients the test deemed to be at low risk had a median overall survival of 52 months; patients identified as having intermediate risk by the test lived for 14 months; and those in the high risk category had median survival of 1 month. There were 27 low risk, 56 intermediate risk, and 2 high risk patients in the cohort as determined by Castle’s test.

This prospectively designed study was the second clinical validation trial that Castle performed for DecisionDx – Mesothelioma. “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,” the company said in a statement.

As part of the technical validation trial, researchers developed protocols under CAP-accredited and CLIA-certified methodology to gauge how well the test analyzed FFPE tissue. The tests showed 91 percent concordance analyzing FFPE tissue compared to frozen samples. The test had no technical failures in this study.

There are 3,000 newly diagnosed cases of mesothelioma annually in the US. The rare illness starts in the lining covering internal organs, with 75 percent of cases affecting the lining of the lungs. Most commonly, mesothelioma occurs in men of Caucasian and Hispanic descent, 65 years or older, who have been exposed to asbestos. The disease can be treated with invasive surgery in some, but for most people it’s incurable.

The latest research from Castle suggests that DecisionDx – Mesothelioma may be a tool that doctors can use to better assess the prognosis of their patients and make treatment decisions accordingly. "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," Raphael Bueno, associate chief of thoracic surgery at Brigham and Women’s and co-inventor of the technology that Castle licensed for the test, said in a statement. "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."