Castle Biosciences Announces Availability of Esophageal Cancer Test Designed to Identify Patients Who are Resistant to Pre-Operative Chemoradiation Therapy

FRIENDSWOOD, Texas, June 19, 2013 /PRNewswire/ -- Castle Biosciences Inc. announced today the availability of DecisionDx-EC, a multi-biomarker test designed to predict which esophageal cancer patients are resistant to, and therefore unlikely to benefit from, the standard treatment of chemoradiation therapy prior to surgery.

Each year, nearly 18,000 people are diagnosed with esophageal cancer in the U.S., and approximately 15,000 will die, making it one of the more deadly cancers. 

Esophageal cancer treatment guidelines recommend chemotherapy and radiation therapy (CTRT) prior to surgical intervention to reduce tumor size and stabilize the disease. The new test helps to determine which tumors are unlikely to respond to these treatments and enables physicians and their patients to carefully consider the risks of regimens to which response is unlikely.

"A recent study indicated that patients who do not respond to chemoradiation not only suffer the toxicities, morbidities and costs associated with these treatments, but they also have shorter disease-free and overall survival times than those treated with surgery alone," commented Derek Maetzold, President and CEO of Castle Biosciences Inc. "Data show that about 25% of esophageal cancer patients have tumors that are likely to be unresponsive to traditional CTRT regimens. With information provided by the new DecisionDx-EC test, those patients could consider avoiding the potentially harmful effects of chemoradiation therapy."

Until now, there were no validated modalities (clinical, pathological or molecular) which provided information to physicians for determining which esophageal cancer patients will likely benefit from CTRT versus other therapeutic intervention.

The DecisionDx-EC test predicts CTRT resistance by analyzing the localization of three protein biomarkers, NFkB, GLI1 and sonic hedgehog (SHH), from esophageal tumor tissue biopsied prior to treatment. These pathways are known to mediate resistance to radiation and chemotherapy. 

The test stratifies patients into two distinct classifications:

Ex-CTRT: Extreme resistance to chemoradiation (College of American Pathologists Tumor Regression Grade 3 or >50% residual tumor).

Response to CTRT: Any level of response to chemoradiation therapy (College of American Pathologists Tumor Regression Grade 0-2 or from 0 to </=50% residual tumor).

Clinical Validation
The DecisionDx-EC test has undergone extensive technical and clinical validation in localized esophageal adenocarcinoma, with the initial phases completed in research laboratories at The University of Texas MD Anderson Cancer Center (MD Anderson), where the test was discovered. The results from this development study and first clinical validation study were presented at the American Society of Clinical Oncology meeting in 2011. Castle Biosciences exclusively in-licensed the proprietary test from MD Anderson and initiated both analytical and clinical validation studies in a CLIA laboratory setting. The analytical studies required over 250 specimen runs to optimize the assay under CLIA requirements. A second independent blinded clinical validation study was then initiated and recently completed. This was a multi-center, prospectively planned study using archival tissue samples. Data from this study and additional ongoing clinical use studies will be presented at upcoming scientific meetings.

More information about the test and disease can be found at www.MyEsophagealCancer.com.

About Esophageal Cancer 
Esophageal cancer is a potentially fatal cancer affecting the esophagus—a long, hollow tube connecting the throat and the stomach. Each year esophageal cancer afflicts about 18,000 new patients in the U.S. and kills about 15,000. While the exact cause is unknown, the disease appears to be 3 to 4 times more frequent in men than in women and occurs more often in those over the age of 55. Some common risk factors include Barrett's esophagus, acid reflux, tobacco and alcohol use, being overweight and exposure to certain chemicals.

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 melanoma, thymic cancer, skin melanoma and brain cancers. More information can be found at www.castlebiosciences.com.

SOURCE Castle Biosciences Inc.