Actionable molecular alterations in veterans with advanced cholangiocarcinoma.

Abstract

548 Background: Cholangiocarcinoma (CCA) requires integrated efforts to understand the heterogeneity in available molecular targets. Chemotherapy remains a non-selective standard of care, however defining distinct populations with molecular actionability remains a critical need. The Veteran Health Administration’s (VHA) National Precision Oncology Program (NPOP) was established to characterize comprehensive genomic profiles across the integrated VHA network. Methods: Veterans with CCA underwent next-generation sequencing (NGS) with FoundationOne CDx, which enhanced sensitivity in the reporting of gene fusions. Analysis included dedicated chart review for date of diagnosis and survival utilizing the VHA’s Corporate Data Warehouse. Molecular alterations included mutations(mut), amplifications (amp) and fusion/rearrangements (fus). Log-rank Kaplan-Meier survival analysis was stratified by primary tumor location, and actionable driver alterations defined by VA Clinical Pathways. Results: Veterans diagnosed with CCA (07/2008-04/2023) underwent tissue-based NGS (n=483) including 96 unique VHA sites with male predominant population (96.9%). There was a predominance of localized disease at clinical presentation (55.3%). A summary of common pathogenic variants is provided (see table). Actionable alterations defined as IDH1mut, FGFR2fus, ERBB2amp, BRAFmut (V600E), and MSI-H collectively represented 21.1% of all Veteran CCA. The largest population was intrahepatic CCA (n=327) with actionable alterations including IDH1mut (13.5%), ERBB2amp (4.3%), and FGFR2fus (4.3%). Data suggested improved overall survival (OS) in IDH1mut Intrahepatic CCA including median OS 19.8 months (mo) v. 10.7 mo (p<0.03). ERBB2amp (n=32) was enriched in extrahepatic (8.1%) and gallbladder cancer (17.2%), however did not improve OS including 7.1 mo in ERBB2amp v. 13.2 mo in wildtype (p=0.15). PIK3CAmut CCA (n=35) was found to confer inferior OS across the population with median OS of 7.5 mo v. 13.2 mo in wildtype (p<0.02). Additional pathologic mutations in genes of homologous recombination deficiency (31.7%), PIK3CA (7.2%), and amplifications in MDM2 (5.0%). Conclusions: Across an integrated healthcare system of Veterans, actionable molecular alterations from VA Pathways were seen in 21.1% of the population. Further data is needed to clarify the prognostic versus predictive value of integrated precision-based strategies in clinical practice. The Veteran population includes important molecular subtypes to consider in future prospective trial design. [Table: see text]