Successful treatment of refractory FLT3-mutaed acute myeloid leukemia with gilteritinib in a pediatric patient

Abstract

Internal tandem duplication (ITD) mutations in FLT3 are common in acute myeloid leukemia (AML) and are associated with poor prognoses. Here, we report the case of a pediatric patient with FLT3-ITD-positive refractory AML treated with gilteritinib, a FLT3 inhibitor. A 13-year-old boy diagnosed as having FLT3-ITD-positive AML de novo was initially treated with cytarabine, mitoxantrone hydrochloride, and etoposide. At the end of this induction therapy, a bone marrow evaluation revealed no response (90% blasts). The patient was treated with a second phase of standard induction chemotherapy followed by oral administration (80 mg/day) of gilteritinib, a tyrosine kinase inhibitor. He showed an excellent response to this therapy and achieved complete remission as shown by bone marrow evaluation. He then completed the second and third courses of chemotherapy with gilteritinib. He displayed sepsis and herpes zoster, which were considered grade 3–4 adverse events regardless of the treatment. He also exhibited treatment-related adverse events: elevated aspartate aminotransferase and alanine aminotransferase levels. He was in complete remission when he underwent a human leukocyte antigen (HLA) -mismatched (mismatch at the HLA-DR locus) unrelated donor allogeneic transplant. His one-month bone marrow aspiration demonstrated 99% donor chimerism and FLT3-ITD-negative remission. This case highlights the finding that the use of gilteritinib in combination with chemotherapy is well tolerated and effective, even in patients with FLT3-ITD-positive refractory AML. This treatment offers hope to some individuals with similar cases.