Abstract B186: TPX-0005, a polypharmacology inhibitor, overcomes ALK treatment resistance from acquired mutations, bypass signaling, and EMT

Abstract

Abstract ALK kinase inhibitors have achieved tremendous success in the treatment of lung cancer patients with abnormal ALK gene. However, the emergence of drug resistance limits their long-term clinical applications. The mechanisms of resistance often include gene amplification, acquired mutations, bypass signaling, and epithelial-mesenchymal transition (EMT). More than 10 different mutations have been identified in clinic, and recently the compound mutations represent new challenges after multiple ALK inhibitor treatments. The bypass and EMT-based resistance mechanisms constitute a large portion of the resistant patient population. None of the current ALK inhibitors can overcome bypass or EMT-based resistance when applied as a single-agent therapy. Therefore, a different strategy needs to be deployed for the design of new-generation ALK inhibitors to overcome multi-resistance mechanisms simultaneously. TPX-0005, a novel three-dimensional macrocycle with a much smaller size than current ALK inhibitors in the clinic, was designed to overcome clinical resistance mutations systematically. TPX-0005 potently inhibited both wild type and mutant ALK fusion proteins including gatekeeper, solvent front, and compound mutations as shown in the table. In addition to its primary targets, TPX-0005 is also a potent SRC/FAK inhibitor with IC50s of 70-80 nM in H2228 cells. H2228 lung cancer cell line, endogenously expressing EML4-ALKv3 protein, is refractory to crizotinib and ceritinib. The upregulation of multiple RTKs including EGFR and IGFR, as well as cancer stem cell marker CD44 and mesenchymal marker vimentin, is believed to induce the primary resistance to selective ALK inhibitors. Inhibition of SRC/FAK kinases will modulate bypass RTK expression, cancer stem-like properties, and EMT to restore the sensitivity to ALK inhibition. TPX-0005 dose-dependently downregulated EGFR, CD44, and vimentin expression levels via SRC/FAK inhibition. TPX-0005 effectively inhibited cancer cell migration in wound healing assays, and induced dramatic tumor regression in human PDX NSCLC tumor model. In addition, TPX-0005 significantly extended survival time in mouse H2228 orthotopic brain tumor model. Overall, TPX-0005 exerts unprecedented polypharmacology profile for combating multiple resistance mechanisms. A phase 1/2 clinical trial of TPX-0005 is actively being pursued (NCT03093116). EML4-ALK Ba/F3 Cell Proliferation Assay IC50 (nM)InhibitorWTG1202RL1196ML1198F/C1156YL1198F/G1202RL1198F/L1196MTPX-000517.820.5501.10.234.8Crizotinib74.8359.47132243.7350.7Ceritinib2.138861123476.81794Alectinib18.950713115813691249Brigatinib11.8399131181187341Lorlatinib0.7ND1889131.61169 ND: not determined Citation Format: Dayong Zhai, Wei Deng, Evan Rogers, Zhongdong Huang, Jeffrey Whitten, John Lim, Yishan Li, J. Jean Cui. TPX-0005, a polypharmacology inhibitor, overcomes ALK treatment resistance from acquired mutations, bypass signaling, and EMT [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B186.