FGFR blockade inhibits targeted therapy-tolerant persister in basal FGFR1- and FGF2-high cancers with driver oncogenes.

Cancer cell resistance arises when tyrosine kinase inhibitor (TKI)-targeted therapies induce a drug-tolerant persister (DTP) state with growth via genetic aberrations, making DTP cells potential therapeutic targets. We screened an anti-cancer compound library and identified fibroblast growth factor receptor 1 (FGFR1) promoting alectinib-induced anaplastic lymphoma kinase (ALK) fusion-positive DTP cell's survival. FGFR1 signaling promoted DTP cell survival generated from basal FGFR1- and fibroblast growth factor 2 (FGF2)-high protein expressing cells, following alectinib treatment, which is blocked by FGFR inhibition. The hazard ratio for progression-free survival of ALK-TKIs increased in patients with ALK fusion-positive non-small cell lung cancer with FGFR1- and FGF2-high mRNA expression at baseline. The combination of FGFR and targeted TKIs enhanced cell growth inhibition and apoptosis induction in basal FGFR1- and FGF2-high protein expressing cells with ALK-rearranged and epidermal growth factor receptor (EGFR)-mutated NSCLC, human epidermal growth factor receptor 2 (HER2)-amplified breast cancer, or v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-mutated melanoma by preventing compensatory extracellular signal-regulated kinase (ERK) reactivation. These results suggest that a targeted TKI-induced DTP state results from an oncogenic switch from activated oncogenic driver signaling to the FGFR1 pathway in basal FGFR1- and FGF2-high expressing cancers and initial dual blockade of FGFR and driver oncogenes based on FGFR1 and FGF2 expression levels at baseline is a potent treatment strategy to prevent acquired drug resistance to targeted TKIs through DTP cells regardless of types of driver oncogenes.