Castle Biosciences, Inc. announced new data from a study further confirming the performance of its DecisionDx-UM test as a robust independent predictor of metastasis-free survival (MFS) in patients diagnosed with UM. Further, the study provides prospective validation data supporting Preferentially Expressed Antigen in Melanoma (PRAME) 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 (ARVO) 2024 Annual Meeting in Seattle.

Uveal melanoma is an aggressive cancer of the eye, and despite high primary tumor cure rates, metastatic disease spread eventually impacts about half of all patients. The DecisionDx-UM test is considered the standard of care in the management of newly diagnosed UM to assist in determining risk of metastasis, which is critical for informing appropriate treatment plans. Details regarding the presentation at ARVO are included below: Oral Presentation Title:Collaborative Ocular Oncology Group study 2 (COOG2): Prospective multi-center validation of the 15-gene expression profile (GEP)/PRAME molecular prognostic tool for uveal melanoma in 1586 patients.

Session Type: Paper Session (May 8, 2024). Presentation Number: 4273. Summary: 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 (HR 6.03; 95% CI, 4.49-8.09); P<0.001), followed by PRAME status (HR 1.77; 95% CI, 1.39-2.27; P<0.001). 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 (versus PRAME-). When considered together, five-year MFS rates were 95.6% (95% CI, 93.9-97.4) for Class 1/PRAME-, 80.6% (73.9-87.9) for Class 1/PRAME+, 57.6% (50.6-65.7) for Class 2/PRAME- and 44.8% (38.0-52.8) 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. J. William Harbour, M.D., ophthalmologist, ocular oncologist, and professor and chair of the department of ophthalmology at UT Southwestern Medical Center, is a leading innovator in the treatment and study of UM and an executive committee member of the COOG.

As the original developer of the DecisionDx-UM test, which was licensed to Castle in 2009, Harbour continues to drive important advancements in the treatment of UM and co-authored this study with Correa.