Response and long-term survival in stage IV lung adenocarcinoma as predicted by serial 3-D explant analyses with molecular correlates: Tumor biology as evolutionary biology.

e20545 Background: The principles of evolutionary biology have been the subject of intense investigation in cancer. The TraceRx program conducts serial biopsies to map genomic (NGS) tumor evolution over time (Al Bakir, Nature, 2023). We applied serial Ex Vivo Analysis of Programmed Cell Death (EVA/PCD) on tissues from a patient with Stage IV NSCLC over a 12 year period to map phenotypic tumor evolution. Recurrences provided tissue for serial EVA/PCD analyses that were correlated with NGS. Methods: NGS was conducted by Foundation Medicine in accordance with established protocols. EVA/PVD analyses were conducted on surgical and core biopsies as previously described (Nagourney, Anticancer Res, 2012). Tissues were mechanically and enzymatically disaggregated to provide explants for analysis. Dose response curves were interpolated to provide lethal concentration 50 % (LC50) with drugs selected by LC50 standard-deviation Z-scores compared a 15,000-patient database. Synergy was conducted by the method of Chou and Talalay. Results: 1) September, 2013: 67 year old woman with newly diagnosed Stage IV NSCLC, EGFR & ALK (-) received assay-directed Carboplatin & Paclitaxel & Irinotecan (Socinski, M Cancer 2002) with remission lasting 12 months 2) October, 2014: Progressive disease led to accrual to MK 3475 (Pembrolizumab) trial and 2 nd remission lasting 22 months. 3) August, 2016: Disease progression led to supraclavicular node biopsy. EVA/PCD identifies unexpected activity for Vemurafenib, the B-RAF inhibitor. NGS confirms BRAF V600E mutation. Dabrafenib & Trametinib provide 3 rd durable remission lasting 41 months. 4) January 2020: New lung mass biopsy. EVA/PCD identifies unexpected activity for Gefitinib. NGS confirms new, previously not detected EGFR mutation (del 19). Osimertinib provides 4 th durable remission lasting 29 months. 5) May, 2022: Disease progression led to lung biopsy. EVA/PCD identifies EGFR-TKI synergy with Vinorelbine providing 5th remission lasting to the present time, 12 years since original diagnosis. Conclusions: Tumor biology reflects evolutionary biology. Tumors subjected to therapeutic intervention must survive or succumb to injury mediated by programmed cell death. Therapy resistance represents the upregulation of cellular pathways that provide survival advantage, creating a niche for tumor clonal proliferation. We report an example, measured both phenotypically and genotypically, of the process in real-time, as each stressor (cytotoxic, immune or signal transduction-related) promoted successive sub-clones, each adapted to the evolutionary pressure exerted by clinical therapy. We show that combining phenotypic and genotypic platforms offers the opportunity to interrogate new tumor clonal variants as they arise to identify vulnerabilities that can be exploited therapeutically.