A Multikinase Inhibitor AX-0085 Blocks FGFR1 Activation to Overcomes Osimertinib Resistance in Non-Small Cell Lung Cancer

<b>Background:</b> Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) with high efficacy in treating patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR-activating mutations. Although osimertinib is a frontline anticancer agent for NSCLC, several patients inevitably develop tumor recurrence caused by osimertinib resistance. The activation of anexelekto (AXL) or fibroblast growth factor receptor 1 (FGFR1) is reported as a major factor driving osimertinib resistance in NSCLC. Thus, targeting AXL and FGFR1 offers the potential to overcome osimertinib resistance. <b>Methods:</b> In this study, we generated osimertinib-resistant cell lines from EGFR-mutant NSCLC cell lines in vitro and investigated the biological significance of AX-0085 on these cell lines by conducting transcriptomic analyses. <b>Results:</b> The expression of several genes associated with MAPK, ERK, and FGF receptor signaling pathways, including AXL, was altered upon AX-0085 treatment of osimertinib-resistant cells. Furthermore, AX-0085 treatment effectively blocked AXL and FGFR1 activation and sensitized osimertinib-resistant cells. Additionally, AX-0085 inhibited AXL and FGFR1-dependent oncogenic events, including cell proliferation, clonogenicity, and migration. <b>Conclusions:</b> The dual inhibition of AXL and FGFR1 by AX-0085 can overcome acquired osimertinib resistance, supporting its potential as a therapeutic strategy for treating patients with osimertinib-resistant tumors.