Gilteritinib Monotherapy as a Transplant Bridging Option for a Patient with FLT3-Mutated Acute Promyelocytic Leukemia Who Developed a Second Relapse after All-Trans Retinoic Acid plus Chemotherapy, Arsenic Trioxide, and High-Dose Cytarabine Therapy

We report a case of FLT3-mutated APL who developed disease relapse despite all-trans retinoic acid (ATRA) + chemotherapy, and re-induction chemotherapy with arsenic trioxide (ATO) and high-dose (HD) cytarabine (Ara-C) therapy failed to yield complete remission. Because the leukemic cells were resistant to all the aforementioned therapies, we started the patient on monotherapy with gilteritinib, a selective FLT3-inhibitor, as an alternative re-induction treatment option rather than further intensive chemotherapy. The patient showed complete hematologic remission in response to this therapy. This case serves as supporting evidence for the use of single-agent therapy with gilteritinib as a bridge to transplantation in patients with refractory FLT3-mutated APL.