Castle Biosciences Announces Availability of DecisionDx-Melanoma Test to Identify Stage I & II Melanoma Patients at High Risk of Metastasis

FRIENDSWOOD, Texas, June 3, 2013 /PRNewswire/ -- Castle Biosciences Inc. announced that data from studies of its DecisionDx-Melanoma test are being presented today at the 49^th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago (Abstract #9022).  Results show that the gene expression profile test strongly predicts metastatic risk in Stage I or II melanoma patients who have no sign of disease beyond the original tumor, suggesting a more precise prognostic tool to guide subsequent cancer surveillance and treatment. The test is available to physicians today.

"The results of our studies showed that the biological information provided by the DecisionDx-Melanoma test helped to identify those patients who are actually at high risk of metastasis, but were classified as lower risk under current staging methods," said David H. Lawson, M.D., Professor of Hematology & Medical Oncology, Winship Cancer Institute, Emory University and study author. "These results showed that the test accurately predicted metastatic risk independently of all current staging methods."

Each year in the U.S. approximately 60,000 patients are diagnosed with Stage I or II (non-metastatic) skin melanoma. Of these, 8,500 will see their disease metastasize to a distant location such as the brain, lung or skin within 5 years. Physicians are unable to accurately predict which patients are most likely to metastasize using current staging methods. 

The DecisionDx-Melanoma test is designed to predict metastasis by measuring the level of expression of 31 genes in the tumor. The test stratifies patients as Class 1 (low risk of metastasis), or Class 2  (high risk of metastasis). To date, the test has analyzed archived tumor samples from more than 400 Stage I and II melanoma patients in prospectively designed studies. More information about the test and disease can be found at www.skinmelanoma.com.

According to Pedram Gerami, M.D., Associate Professor of Dermatology, Director of Melanoma Research at the Northwestern Skin Cancer Institute, Northwestern University, and study co-author, "These results showed that patients stratified by this test as Class 2 had a 72% risk of metastasis at year 5. In comparison, patients with advanced Stage III melanoma have a lower risk of approximately 50%. This suggests non-metastatic Class 2 patients are at a very high risk and should be considered for aggressive surveillance and therapeutic interventions that are routinely given to Stage III patients."

Study Results
Data from the training and validation studies will be presented by Dr. Lawson in a poster discussion. For all tumor samples, gene expression profiles were measured from formalin-fixed, paraffin-embedded biopsies or wide excisions of primary melanoma tumors from patients presenting at Stage 0-IV. Eighty two percent were Stage I or II.

Kaplan-Meier analysis showed 5-year visceral metastatic free survival (MFS) rates of 93% and 22% for predicted Class 1 and Class 2, respectively, in the training set of 164 tumor samples (p<0.0001).

The independent validation study included 92 tumor samples, with 5-year MFS rates of 96% and 28% for Class 1 and Class 2, respectively (p<0.0001).

"We are focused on raising awareness in the dermatology and oncology communities of the test's utility in identifying those patients with earlier stage melanoma who should be managed as high risk for metastasis," said Derek Maetzold, President and CEO of Castle Biosciences. "This objective information, in combination with traditional staging methods, can better determine who should have more aggressive follow-up care."

The Company also announced that results of a study of its thymic carcinoma gene expression test were presented at ASCO (Abstract #7605). The data suggests that the 10-gene signature test can predict metastatic behavior in thymic carcinomas with a very high degree of accuracy, and can help guide appropriate patient treatment. Additional validation studies have been performed and will be published this year.

About Melanoma
Cutaneous melanoma is diagnosed in approximately 76,000 people in the U.S. each year, according to the American Cancer Society. Seventy-five percent are diagnosed as Stage I or II, meaning there is no evidence of the melanoma spreading beyond the primary tumor. It is not the most prevalent form of skin cancer, but it is the most aggressive. Unlike other more common skin malignancies like basal cell and squamous cell carcinomas, melanoma often spreads widely to other parts of the body, either via the lymphatic or blood system, resulting in cancers of distant organs including the brain or lungs.  So, while it represents just 4% of skin cancers, melanoma accounts for about 80% of skin cancer-related deaths.  

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, thymoma, and brain cancers. More information can be found at www.castlebiosciences.com.

SOURCE Castle Biosciences Inc.