Castle Biosciences Announces Launch of New Eye Cancer Test to Measure Expression of PRAME Gene

PRAME expression, when combined with DecisionDx-UM test results, correlates with increased risk of metastasis in patients with uveal melanoma

FRIENDSWOOD, Texas--(BUSINESS WIRE)--Castle Biosciences, Inc., a provider of molecular diagnostics to improve cancer treatment decisions, today announced the launch of DecisionDx^®-PRAME, a gene expression profile (GEP) test designed to measure gene expression levels of PRAME (Preferentially Expressed Antigen in Melanoma). PRAME expression has been associated with an increased risk of metastasis in patients diagnosed with uveal melanoma (eye cancer). Castle Biosciences is now offering the DecisionDx-PRAME test as an optional add-on test for patients undergoing evaluation with its market leading test for uveal melanoma, DecisionDx^®-UM.

“Our research shows that the expression of PRAME above a specific threshold in uveal melanoma is a strong predictor of increased metastatic risk in patients with a Class 1 uveal melanoma who otherwise would be assumed to be at low risk,” commented J. William Harbour, M.D. of the University of Miami School of Medicine. “By combining results of the gene expression profile and PRAME tests, we believe we can enhance the accuracy of metastatic risk stratification in patients with uveal melanoma.”

“DecisionDx-UM is the standard of care to identify patients whose eye tumors are likely to spread and become deadly,” commented Derek Maetzold, President and CEO of Castle Biosciences. “We believe the DecisionDx-PRAME test used in conjunction with the results of the DecisionDx-UM test can enable further precision of a patient’s predicted risk for metastasis and help guide physicians and patients to the most appropriate follow-up care regimens.”

The Company’s DecisionDx-UM test for uveal melanoma is the most widely used prognostic test to stratify the risk of a patient’s primary uveal melanoma tumor becoming metastatic. It has been used on over 6,000 clinical samples from more than 180 U.S. ocular oncology specialists. While the risk for Class 1 patients has been shown to be consistently low across multiple prospective studies, a small number of Class 1 patients will ultimately experience metastasis. Sub-classification further identifies the lowest risk Class 1 patients (Class 1A) and the intermediate risk Class 1 patients (Class 1B).

More recently, as published in Clinical Cancer Research¹, Dr. Harbour and colleagues searched for novel biomarkers for Class 1 tumors that metastasize using whole transcriptomic analysis. PRAME was identified as the most accurate biomarker for Class 1 tumors that would metastasize versus those that would not metastasize. A threshold of PRAME expression to signify positivity in uveal melanoma tumors was determined. The Class 1 tumors that metastasized in Dr. Harbour’s study were all positive for PRAME expression according to this threshold. Castle Biosciences performed technical validation of this threshold in a 958 patient sample study. In addition, Dr. Harbour’s research also found that patients with high metastatic risk Class 2 tumors that were positive for PRAME expression may be at higher risk of earlier metastasis compared to patients with Class 2 tumors that were PRAME negative².

The DecisionDx-PRAME test is available now to physicians as an optional add-on to the DecisionDx-UM test. Physicians can request this new test by electing the additional DecisionDx-PRAME test option on the DecisionDx-UM requisition form.

Additional studies of uveal melanoma patient tumors are planned, including a prospective, multicenter trial led by Dr. Harbour.

About DecisionDx-UM
The DecisionDx-UM test measures the gene expression profile (GEP), or molecular signature, of an individual’s tumor and identifies with high accuracy the likelihood of metastasis. The accuracy of the test has been validated in multiple prospective multi-center and single-center performance studies^3-7. The DecisionDx-UM test is standard of care in the management of uveal melanoma in the majority of ocular oncology practices. It is the only test for uveal melanoma that has achieved National Cancer Institute/National Comprehensive Cancer Network Level of Evidence 1A, a critical factor in test adoption and clinical decision-making. Additionally, the American Joint Committee on Cancer recommends gene expression profile testing for use as the results are “clinically significant.” The American Joint Committee on Cancer (AJCC, version 7, 2010) is the only national organization that reviews uveal melanoma and the DecisionDx-UM test is the only clinically available GEP test for use in the U.S. The test has been validated in multiple prospective and retrospective studies. More information about the test and disease can be found at www.MyUvealMelanoma.com.

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 followup care based on the individual molecular signature of their tumor. The Company currently offers tests for patients with uveal melanoma (DecisionDx^®-UM; www.MyUvealMelanoma.com, and DecisionDx^®-PRAME) and cutaneous melanoma (DecisionDx^®-Melanoma; www.SkinMelanoma.com), with development programs in other underserved cancers. Castle Biosciences is based in Friendswood, TX (Houston), and has laboratory operations in Phoenix, AZ. More information can be found at www.castlebiosciences.com.

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

¹ Field MG, Decatur CL, Kurtenbach S, et al. PRAME as an independent biomarker for metastasis in uveal melanoma. Clin Cancer Res 2016;22(5):1234-42. doi:10.1158/1078-0432.ccr-15-2071.

² Field MG, Durante MA, Decatur CL, et al. Epigenetic reprogramming and aberrant expression of PRAME are associated with increased metastatic risk in Class 1 and Class 2 uveal melanomas. Oncotarget 2016;7(37):59209-19. doi: 10.18632/oncotarget.10962.

³ Onken MD, Worley LA, Char DH, et al. Collaborative Ocular Oncology Group report number 1: Prospective validation of a multi-gene prognostic assay in uveal melanoma. Ophthalmology 2012;119:1596-603.

⁴ Correa ZM & Augsburger JJ. Sufficiency of FNAB aspirates of posterior uveal melanoma for cytologic versus GEP classification in 159 patients, and relative prognostic significance of these classifications. Graefes Arch Clin Exp Ophthalmol 2014;252:131-5.

⁵ Demirci H, Ozkurt ZG, Slimani N, et al. Gene expression profiling test of uveal melanoma: prognostic validation. In American Society of Ophthalmic Plastic & Reconstructive Surgery Fall Scientific Symposium. 2015: Las Vegas, NV.

⁶ Correa ZM & Augsburger JJ. Independent prognostic significance of gene expression profile class and largest basal diameter of posterior uveal melanomas. Am J Ophthalmol 2016;162:20-7e1.

⁷ Plasseraud KM, Cook RW, Tsai, T. Clinical performance and management outcomes with the DecisionDx-UM gene expression profile test in a prospective multicenter study. J Oncology 2016; doi:10.1155/2016/53257622016.