Abstract 848: Preclinical antitumor activity of S 49076, a novel MET / AXL / FGFR kinase inhibitor and molecular stratification for tumor sensitivity

Aberrant activity of receptor tyrosine kinases (RTKs) has been associated with tumor progression in a wide variety of human malignancies, making them promising drug targets for cancer therapy. Although, in some instances, specific inhibition of just one of these RTKs suffices for inhibition of tumor progression, in the majority of cases, targeting more than one RTK could be required for therapeutic efficacy. Moreover, increased expression or activation of RTKs is often associated with resistance to standard chemotherapy agents or signal transduction modulators. S 49076 is a novel, potent, ATP-competitive tyrosine kinase inhibitor of the RTKs MET, AXL and FGFR. S 49076 blocks autophosphorylation of these RTKs and their downstream signaling in cells with IC50 values of less than 50 nM in the case of MET and AXL, and at below 200 nM for FGFR1/2/3. In vitro, S 49076 inhibits the proliferation of MET- and FGFR2- dependent gastric cancer cells, blocks MET-driven migration of lung carcinoma cells and inhibits colony formation of hepatocarcinoma cells overexpressing FGFR2 and AXL. In vivo, oral administration of S 49076 inhibits MET autophosphorylation and tumor growth in subcutaneous GTL-16 human gastric carcinoma and U87-MG human glioblastoma at 6 mg/kg/day. In FGFR2-dependent SNU-16 gastric tumors S 49076 inhibits FGFR2 autophosphorylation, downstream signaling and tumor growth at 25 mg/kg/day. In a panel of 53 patient-derived tumors and 14 cell lines of diverse origin growing in three-dimensional in vitro culture, twenty-five (37%) were found to be sensitive to S 49076 at 1 µM or less. In the majority of cases, analysis of the expression, activation and mutation status of MET, AXL, FGFR1/2/3 and other target kinases of S 49076 as well as that of major signaling proteins enabled hypotheses to be made concerning the sensitivity or resistance to S 49076. Moreover, in many of these resistant tumors, a rationale for association of S 49076 with other targeted therapies emerged. Examples of the efficacy of such combined therapies will be shown. Based on these preclinical studies showing a favorable and novel pharmacological profile of S 49076, a phase I study is currently underway in patients with advanced solid tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 848. doi:1538-7445.AM2012-848