O-001Efficacy of TAS-120, an irreversible fibroblast growth factor receptor (FGFR) inhibitor, in cholangiocarcinoma patients with FGFR pathway alterations who were previously treated with chemotherapy and other FGFR inhibitors

Introduction: TAS-120, an oral and highly selective, irreversible FGFR1-4 tyrosine kinase inhibitor, has demonstrated inhibition of cancer cell growth in human xenografts of tumors bearing FGFR aberrations. TAS-120 inhibited mutant and wild-type FGFR2 with similar IC50 (wild-type FGFR2, 0.9 nM; V5651, 1-3 nM; N550H, 3.6 nM; E566G, 2.4 nM) and has shown efficacy in cell lines with acquired resistance to FGFR inhibitors. In this Phase I study in patients with advanced solid tumors, TAS-120 was evaluated at 8-24 mg once daily (QD). 20 mg QD was determined as the maximum tolerated dose/recommended Phase II dose, while 24 mg QD had dose-limiting toxicity. Here we report results from cholangiocarcinoma (CCA) patients enrolled in this Phase I study.