Castle Biosciences, Inc. Announces New Data from the First Independent Validation of the Recently Published Collaborative Ocular Oncology Group Study No. 2

Published: 2025-05-09 07:00:00 ET CSTL

Published on 05/09/2025 at 07:00, updated on 05/09/2025 at 08:50

Castle Biosciences, Inc. announced new data from the first independent validation of the recently published Collaborative Ocular Oncology Group Study No. 2 (COOG2.1) by Harbour et al.1 The data, from a real-world cohort of 1,297 patients with uveal melanoma (UM), was presented at the Association for Research in Vision and Ophthalmology (ARVO) 2025 Annual Meeting in Salt Lake City. The findings provide further support for adding Preferentially Expressed Antigen in Melanoma (PRAME) gene expression information to the DecisionDx-UM test result to further refine metastatic risk prediction for patients with UM, which is a rare but aggressive eye cancer.

The abstract may be viewed using the ARVO 2022 mobile meeting planner. Presentation Number 981: PRAME status as a risk modifier of 15-gene expression profile class: Evidence from a real-world cohort the real-world cohort of 1297 uveal melanoma patients. Presentation Type: Poster Session; Session Number: 154; Session Title: Uveal Melanoma; Summary: An ongoing collaboration with the National Cancer Institute's Surveillance, Epidemiology and End Results (NCI SEER) Program enabled linkage of UM patient records with such patients' DecisionDx-UM and PRAME test results.

In a large, real-world, population-based cohort of patients with UM, this study aimed to validate the findings from the prospective COOG2.1 study, which found that adding the reported expression of the PRAME gene to the DecisionDx-um class result can further refine risk by subdividing Class 1 and Class 2 tumors based on PRAME positive (+) versus negative (-) status. Consistent with the COOG2.1 studies, the findings shared at ARVO demonstrate that co-reporting of DecisionDx-UM class and PRAME status provides additional insights into a patient's likelihood of metastasis to better inform treatment pathway decisions. DecisionDx-UM is Castle Biosciences' 15-gene expression profile (GEP) test that uses an individual patient's tumor biology to predict individual risk of metastasis in patients with uveal melanom (UM).

Further, the National Comprehensive Cancer Network (NCCN) guidelines for UM include the DecisionDx-UM tests result as a prognostic method for determining risk of metastasis and recommended differential surveillance regimens based on a Class 1A, 1B and 2 result. These forward-looking statements include, but are not limited to, statements concerning: the ability of the DecisionDx-UM testing to guide more informed, risk-aligned management decisions through the precise risk-stratification of patients with UM; the potential increased risk stratification from including PRAME gene expression information to a patient's DecisionDx-UM test results; and DecisionDx-UM's value in identifying UM patients who may benefit from enhanced surveillance and management strategies to improve outcomes. These forward-looking statements involve risks and uncertainties that could cause actual results to differ materially from those in the forward-looking statements, including, without limitation: subsequent study or trial results and findings may validate earlier study or trial results and findings or may not support the results obtained in these studies, including with respect to the discussion of tests in this press release; actual application of tests may not provide the aforementioned benefits to patients; and the risks set out under the heading "Risk Factors" in the Annual Report on Form 10-K for the year ended December 31, 2024.