Abstract LB233: Preclinical analysis identifies predictive biomarker and potential pathways of resistance to lurbinectedin treatment in small cell lung cancer

Abstract

Abstract Background: Small cell lung cancer (SCLC) is an exceptionally aggressive disease with limited treatment options that typically result in transient responses. SCLC is responsible for approximately 250,000 deaths globally per year. Major hurdles to improving SCLC treatment include the development of rapid chemo-resistance and limited second-line therapies. Lurbinectedin is FDA approved as a second-line treatment for SCLC but shows a response in a subset of patients. Therefore, improved mechanistic understanding and identifying predictive biomarkers of lurbinectedin treatment is a major unmet clinical need. Methods: We treated SCLC cell lines and patient-derived xenograft (PDX) models from all major SCLC subtypes with lurbinectedin. Lurbinectedin-mediated changes in signaling pathways were studied by bulk RNA sequencing, western blot, and flow cytometry. Anti-tumor efficacy and toxicity studies were performed in vivo. Result: All human and PDX-derived SCLC cell lines showed sensitivity to lurbinectedin at a nano-molar concentration ranging from 1.905 to 30 nM. Bulk RNA-seq analysis showed lurbinectedin induced changes in neuroendocrine phenotype, DNA damage response and tumor progression markers in vitro. Single agent treatment of lurbinectedin showed remarkable anti-tumor efficacy in an ASCL1-driven PDX model. RNA sequencing analysis identified modulation of genes in multiple signaling pathways including PI3K-AKT, apoptosis and EMT to be significantly associated with the lurbinectedin response in PDX models. Conclusion: There is an immediate need to understand the subsets of SCLC that would be most sensitive to lurbinectedin and identify predictive biomarkers. We demonstrate MYC as a predictive biomarker for lurbinectedin response. We are the first to show that single agent lurbinectedin shows remarkable anti-tumor efficacy in a ASCL1-driven PDX models of SCLC. Furthermore, our pre and post-lurbinectedin treatment transcriptomic analysis identify the pathways that may contribute to primary or acquired resistance to lurbinectedin in SCLC. Finally, we identity candidate targets that would guide the design of future combination clinical trials with lurbinectedin in SCLC. Citation Format: Subhamoy Chakraborty, Charles Coleman, Deniz Demircioglu, Dan Hasson, Triparna Sen. Preclinical analysis identifies predictive biomarker and potential pathways of resistance to lurbinectedin treatment in small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB233.