Dose-proportional pharmacokinetics was observed following once-daily gilteritinib administration (dose range 20–450 mg).

Gilteritinib concentrations peaked at 2–6 h following single and repeat dosing between 20 and 450 mg and exposure when administered 40 mg was comparable under fasted and fed conditions.

Coadministration of gilteritinib with itraconazole (a strong P-glycoprotein inhibitor and cytochrome P450 [CYP] 3A4 inhibitor) or rifampicin (a strong P-glycoprotein inducer and CYP3A inducer) significantly impacted the gilteritinib pharmacokinetic profile; CYP3A4 or multidrug and toxin extrusion 1 substrates did not present clinically relevant drug–drug interactions when coadministered with gilteritinib.

Unbound gilteritinib was comparable between subjects with hepatic impairment and normal hepatic function, thus dose adjustments are not warranted in patients with hepatic impairment.