Genomic alterations to refine prognostication of patients with metastatic renal cell carcinoma.

626 Background: The IMDC risk score is a valid and simple tool to prognosticate patients (pts) with metastatic renal cell carcinoma (mRCC). Some non-VHL common genomic alterations may be associated with outcomes. We therefore assessed the prognostic value of most commonly mutated genes in mRCC beside VHL overall, and within IMDC risk groups. Methods: We identified patients treated at Dana-Farber Cancer Institute (n = 65) or part of TCGA (n = 33) who had genomic data available and were treated with first line vascular endothelial growth factor tyrosine kinase inhibitors. Information on genomic alterations (GA) focused on PBRM1, BAP1, SETD2, KDM5C and TP53 was extracted. Cox regression was performed to assess the association of each GA with overall survival (OS), adjusting for IMDC risk groups and age. Results: Overall, 98 pts were identified. 96/98 pts had clear-cell histology. Pts distribution by IMDC risk groups was: 7% good, 58% intermediate, 27% poor and 8% unknown. Mutation rates were 27% PBRM1, 17% BAP1, 29% SETD2, 9% KDM5C and 8% TP53. In multivariable models, there was an association between GA and worse OS for BAP1 and BAP1 or TP53 combined (Table). When stratified by IMDC risk groups, GA in BAP1 or TP53 was associated with shorter median OS in poor risk pts [12.1 mo (95%CI 8.3- 24.0) v. 27.6 mo (95%CI 18.9- 53.4), aHR 4.64 (95%CI 1.32-16.4), p = 0.017] and a trend toward worse median OS in intermediate risk pts [20.5 mo (95%CI 7.4-54.6) v. 36.3 mo (95%CI 21.1, NR), aHR 2.11 (95%CI 0.94-4.74)] compared to pts without GA in BAP1 or TP53. Too few death events were observed in good risk pts to assess the prognostic value of GA in BAP1 or TP53. Conclusions: GA in BAP1 or TP53 are prognostic in mRCC and further discriminate pts with distinct outcomes within IMDC risk groups. Validation in larger dataset is ongoing. [Table: see text]