Abstract LB-041: Novel platform to profile variants of uncertain significant (VUS) with preliminary retrospective clinical validation in non-small cell lung cancer (NSCLC)

Abstract

Abstract Background: With the expanding usage of next generation sequencing (NGS) during treatment of NSCLC, an increasing number of variants of uncertain significance are being detected. Therefore, exists an urgent unmet need for a functional assay to reveal the significance of these findings both for naïve patients and those with acquired resistance to targeted therapy. We present feasibility data and retrospective clinical validation for a novel high-throughput cell-based assay (FACT) which profiles alterations by measuring downstream activation of signaling pathways to determine oncogenic grading and prioritize treatment with targeted therapies. Methods: Patients with NSCLC adenocarcinoma that underwent NGS test (tissue based/cell-free tumor DNA) were consented and enrolled. Alterations were profiled using the FACT platform to quantify oncogenic signaling activity and inhibition by targeted therapies. Patient outcomes were compared to in vitro drug sensitivities retrospectively. Results: 9 patients with NSCLC were analyzed using the FACT platform. 17 alterations were functionally profiled (EGFR - 12, ERBB2 - 2, BRAF - 1, PDGFRA - 1 and JAK2 - 1). 12 (70%) mutations were found to be oncogenic, 11 (65%) oncogenic alterations were in actionable genes (EGFR/ERBB2), 7 patients (78%) were treated with targeted therapies. 3 patients had uncommon double point mutations in EGFR profiled on the same DNA construct (cis) and separately (trans) showing distinct oncogenic profiles. Drug inhibition was measured with used targeted therapies and showed concordance with retrospective clinical responses. Conclusions: Functional profiling of alterations found in NSCLC is feasible through the FACT platform and can provide useful insights on the oncogenicity of uncommon variants. Profiling of drug sensitivity was successfully performed in the majority of patients and in vitro sensitivity correlated with observed clinical outcomes. Patient Characteristics-Molecular Profile-Treatment History-ResponsePT #AgeSexStageNGS SourceProfiled MutationsTreatment HistoryClinical Response to TKIs37534FIVTissueEGFR H773_V774insNPHcisplatin/pemetrexed/bevacizumabN/A37674FIVctDNAEGFR M277E/E282A,EGFR E282A,EGFR M277Eafatinibafatinib - no37749MIVTissueEGFR E709_T710>D,EGFR T790M,PDGFRA L379Vafatinib > mild progression of brain mets > addition of avastin and WBRT > T790M positive MAF .01% > osimertinib > progression in lung > osimertinib + afatinibafatinib - yes,osimertinib - no,afatinib+osimertinib - yes37866MIVTissueERBB2 A775_G776insYVMAcisplatin/pemetrexed/bevacizumab + maintenance > pemetrexed > pembrolizumab > afatinib toxicity/marginal response > trastuzumabafatinib - no39072MIVctDNABRAF N581SN/AN/A39133FIVMultipleERBB2 L755_E757>PKcisplatin/pemetrexed > trastuzumab > TDM1 > pembrolizumab > afatinibafatinib - ongoing39762FIVTissueEGFR H835L/L833V,EGFR H835L, EGFR L833V, JAK2 R374Kcisplatin/pemetrexed > afatinibafatinib - yes39866FIVTissueEGFR exon 19 Del (p.Glu746_Ala750delinsdel)osimertinibosimertinib - yes42957MIIaTissueEGFR L858R/A289V,EGFR A289VRLL Lobectomy > adjuvant cisplatin/vinorelbine > (recurrence) Brain metastasis > Surgery+RT > osimertinibosimertinib - yes Citation Format: Benjamin Miron, Gabi Tarcic, Oded Edelheit, Nitza Burck, Michael Vidne, Laila Roisman, Nir Peled. Novel platform to profile variants of uncertain significant (VUS) with preliminary retrospective clinical validation in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-041. doi:10.1158/1538-7445.AM2017-LB-041