Triazole antifungal use for prophylaxis and treatment of invasive fungal diseases for patients receiving gilteritinib

Gilteritinib is primarily metabolized via cytochrome P450 (CYP). Therefore, concomitant administration of strong CYP3A4 inducers or inhibitors is not recommended. We evaluated the incidence of gilteritinib-related adverse events (AEs) in 47 patients who received gilteritinib with or without antifungal triazoles which are known inhibitors of CYP3A4. Reasons for coadministration were antifungal prophylaxis or treatment of suspected or confirmed fungal diseases. Gilteritinib-related AEs were similar in the gilteritinib-triazole group compared to the gilteritinib without triazole group (75 % vs. 55.5 %, P = 0.23). Additionally, severity of AEs, gilteritinib dose reductions (15 % vs. 14.8 %) or discontinuation due to AEs (10 % vs. 22.2 %), and 90-day mortality (35 % vs. 11.1 %) were similar in both groups. Thus, concomitant gilteritinib and triazole therapy is feasible and is not associated with clinically meaningful increase in gilteritinib-related AEs.