Isavuconazole therapy in an FLT3 mutated acute myeloid leukemia patient receiving midostaurin: A case report.

Midostaurin is the first approved FMS-related tyrosine kinase 3 (FLT3) inhibitor indicated for FLT3 mutated acute myeloid leukemia. Midostaurin is a major cytochrome P450 3A4 (CYP3A4) substrate. Coadministration with a strong CYP3A4 inhibitor or inducer can lead to a potential increase or decrease in midostaurin exposure. This report describes a 43-year-old patient with FLT3-internal tandem duplication (FLT3-ITD) positive acute myeloid leukemia who initially presented with leukocytosis and concern for acute leukemia. Following the initiation of induction chemotherapy, the patient developed lung nodules concerning for a fungal infection. Isavuconazole, a moderate CYP3A4 inhibitor, was successfully initiated and maintained, while midostaurin therapy was also administered. Clinicians should be aware and exercise caution when using midostaurin with CYP3A4 inhibitors and inducers.