Abstract 3571: Exploratory biomarker discovery for clinical development of ARQ 087, a potent pan-FGFR kinase inhibitor

Fibroblast growth factor receptor (FGFR) tyrosine kinase family members have gained increasing attention as potential therapeutic targets. Gene amplification, or gain-of-function translocations and mutations of these receptors, have been implicated in a variety of cancers including breast, gastric, bladder, ovarian, endometrial, lymphoma and myeloma. We have previously described the biological profiling of ARQ 087, a potent small-molecule pan-FGFR kinase inhibitor that shows anti-tumor activity in FGFR dysregulated tumor cells in vitro and in vivo. A number of cell lines with genetically-altered FGF receptors were identified that were sensitive in anti-proliferative assays to ARQ 087, including FGFR2 amplified gastric carcinoma lines KATO III and SNU-16, and endometrial lines AN3CA, MFE-296 and MFE-280 harboring FGFR2 mutants, as well as a breast cancer cell line with increased FGFR1 gene copy (MDA MB-157). Western blot pharmacodynamic analysis demonstrates that ARQ 087 inhibits FGFR phosphorylation and downstream pathway markers in these cell lines in a concentration-dependent manner. Using antibody arrays specific for known cytokines as well as regulatory proteins involved in angiogenesis and apoptosis, we have identified a number of protein biomarkers in cell lysates and in conditioned media of sensitive cell lines that changed in response to ARQ 087 exposure. Three proteins (cytochrome c, clusterin, and HTRA2) decreased in SNU-16 (ARQ 087-sensitive, FGFR amplified) but not DLD1 (ARQ 087-resistant, non FGFR expressing) cells. VEGF decreased and IL-1rα increased in SNU-16 but not in DLD1 conditioned media in response to ARQ 087. Furthermore, analysis of mouse plasma from animals bearing AN3CA tumors treated with ARQ 087 revealed a decrease in human VEGF, CXCL16, MMP-9, Serpin E1 and MIF and an increase in RANTES, IL-1β, IP-10, SDF-1, IL-1rα. TNFα, GM-CSF, IL-2, sTREM-1, sICAM-1, MIP-1β, IL-8. In summary, we have identified a number of cell lines from a broad cell line screening campaign that exhibited dysregulated FGFR pathway function and are sensitive to the anti-proliferative effects of ARQ 087. These cell lines, in turn, have been used as models in which to identify candidate biomarkers that may greatly facilitate subsequent clinical evaluation of this molecularly targeted anti-tumor agent. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6