Early-phase trials of selective FGFR4 inhibitors (e.g., fisogatinib/BLU-554; roblitinib/FGF401) showed activity in FGF19-positive or FGFR4/KLB-positive tumours, validating pathway dependence but not yet yielding a registrational success [61,62]. Here, FGFR4 is linked to neoplasm.