ARQ087 (derazantinib) is a pan-FGFR inhibitor which inhibits FGFR2 most potently, with 4.5, 1.8, 4.5, and 34 nM potency for FGFR1/2/3/4, respectively in cell-free assays.33 A phase 1/2 study of ARQ087 (derazantinib) in advanced solid tumors reported only 5% grade 1 hyperphosphatemia.34 An expanded FGFR2-abberrant CCA cohort (N = 35) from this study reported a PR rate of 20% (6/35) and 49% stable disease (17/35). Here, FGFR1 is linked to hyperphosphatemia.