Castle Biosciences announces new data from DecisionDx-Um test study

Castle Biosciences announced new data from a study further confirming the performance of its DecisionDx-UM test as a robust independent predictor of metastasis-free survival in patients diagnosed with UM. Further, the study provides prospective validation data supporting Preferentially Expressed Antigen in Melanoma as a risk refinement tool when considered in the context of a Class 1 or Class 2 DecisionDx-UM test result. The data was presented at the Association for Research in Vision and Ophthalmology 2024 Annual Meeting in Seattle. This prospective, multi-center study included 1,586 patients with posterior UM tumors enrolled across 26 ocular oncology centers in the United States and Canada. In the study, a DecisionDx-UM Class 2 result was the most robust independent predictor of MFS, followed by PRAME status. Patients with Class 2 tumors had considerably worse outcomes than those with Class 1 tumors, regardless of PRAME status; however, PRAME+ tumors fared worse within each GEP class. When considered together, five-year MFS rates were 95.6% for Class 1/PRAME-, 80.6% for Class 1/PRAME+, 57.6% for Class 2/PRAME- and 44.8% for Class 2/PRAME+. Overall, the study confirms the prognostic accuracy of the DecisionDx-UM test and provides the first prospective validation of PRAME status as a risk refinement tool when considered in the context of a Class 1 or Class 2 DecisionDx-UM result. These two tests together can guide more precise and risk-aligned decision-making for patients with UM, including referrals, intensity of imaging surveillance and eligibility for ongoing clinical trials.