Castle Biosciences, Inc., a provider of molecular diagnostics to improve cancer treatment decisions, today announced the publication of results from an independent study of the DecisionDx^®-Melanoma gene expression profile test’s impact on clinical decision-making. This new study of 91 patients with cutaneous melanoma is the third recent publication demonstrating that the DecisionDx-Melanoma test impacts one in two clinical management decisions.

The paper titled, "Impact of Gene Expression Profiling on Decision-Making in Clinically Node Negative Melanoma Patients after Surgical Staging," was recently published by researchers from Oregon Health & Science University (OHSU) in the Journal of Drugs in Dermatology. The study found that DecisionDx-Melanoma test results had a significant role in guiding management and surveillance of patients with cutaneous melanoma. Patient management and follow-up plans were more aggressive for patients with high-risk test results, and were appropriately reduced for those with lower-risk results.

Study Background

Standard of care recommendations for Stage I-IIA melanoma do not include laboratory testing, frequent exams, or imaging, though the majority of people who die each year from melanoma are diagnosed with early-stage disease. Based on the accurate prognosis of DecisionDx-Melanoma in prospective and retrospective validation studies, study authors included the test in the risk assessment of 91 patients treated between September 2015 and August 2016 who also had a sentinel lymph node biopsy (SLNB) performed. A majority of the patients studied (88%) were Stage I or II.

Patients were retrospectively grouped based on recommended follow-up plan: 1) dermatology alone, 2) surgical oncology, 3) surgical oncology with recommendation for adjuvant trial, or 4) medical and surgical oncology. The impact of DecisionDx-Melanoma test results on decisions regarding follow-up recommendations was assessed.

Key Study Findings:

• In this pathologically staged population, 52 patients (58%) had a Class 1 (low risk) result and 38 (42%) had a Class 2 (high risk) result.
• Overall the follow-up recommendations for Class 1 (low risk) and Class 2 (high risk) patients were found to be significantly different (P<0.001), with Class 2 patients receiving more aggressive follow-up.
• Using a prediction model, the DecisionDx-Melanoma test was found to account for 52% of the decisions regarding patients’ follow-up plans. As a comparison, approximately 20% of patients undergoing SLNB are found to be positive.
• For patients who received a Class 1 DecisionDx-Melanoma test result, the majority (58%) were followed by dermatology alone. No Class 2 patients were followed by dermatology alone.
• All patients who received a Class 2 result were followed by surgical oncology, with or without the recommendation for an adjuvant trial or consultation by medical oncology, compared to 42% of Class 1 patients.
• For Stage I patients, 82% of those with a Class 1 result were followed by dermatology alone; all Stage I patients with a Class 2 result were followed by surgical oncology with or without recommendation for adjuvant trial.

"The finding that the 31-gene expression profile test significantly impacted patient management decisions in this study aligns with previous publications demonstrating that the test impacts clinical decision-making in approximately 50% of patients tested," noted study co-author John Vetto, M.D., FACS, Professor of Surgery and Director of the Department of Surgery Cutaneous Oncology Program at OHSU. "It is important to have risk assessment strategies such as the 31-gene expression profile test that allow accurate identification of high-risk patients for more aggressive interventions and appropriate allocation of follow-up resources for low-risk patients."

An interim analysis of this study was previously presented at the 2017 Society of Surgical Oncology Annual Cancer Symposium in Seattle, WA.

About DecisionDx-Melanoma

The DecisionDx-Melanoma test uses tumor biology to predict individual risk of melanoma recurrence and sentinel lymph node positivity independent of traditional factors. Using tissue from the primary melanoma, the test measures the expression of 31 genes. The test has been validated in three multi-center studies that have included 690 patients and have demonstrated consistent results. Performance has also been confirmed in four prospective studies including 702 patients. The consistent high performance and accuracy demonstrated in these studies, which combined have included over 1300 patients, provides confidence in disease management plans that incorporate DecisionDx-Melanoma test results. Prediction of the likelihood of sentinel lymph node positivity has also been validated in two prospective multicenter studies that included over 1400 patients. Clinical impact has been demonstrated in multi-center and single-center studies showing that test results impact approximately 1 in 2 clinical management decisions. 

About Castle Biosciences

Castle Biosciences is a molecular diagnostics 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. 

DecisionDx-Melanoma, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeqare the trademarks of Castle Biosciences, Inc. Any other trademarks are the property of their respective owners.

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