Gilteritinib Yields Five-Year Remission in Relapsed Acute Myeloid Leukemia Case

A 44-year-old man with acute myeloid leukemia achieved complete remission lasting more than five years following treatment with the targeted inhibitor gilteritinib, according to a clinical case report published in Annals of Hematology. The patient, originally diagnosed with NPM1-mutated acute myeloid leukemia, developed an FLT3 internal tandem duplication at the time of hematological relapse following cord blood transplantation, highlighting the critical problem of acquired resistance in this disease setting.

To address the post-transplant relapse, the patient received the FLT3 inhibitor quizartinib as salvage therapy and proceeded to a second allogeneic hematopoietic stem cell transplantation. Quizartinib was continued after the procedure as post-transplant maintenance therapy. However, approximately three months into the maintenance regimen, the patient experienced another hematological relapse, demonstrating disease progression despite ongoing targeted therapy.

Diagnostic assessment at relapse using the LeukoStrat CDx FLT3 Mutation Assay identified a secondary FLT3 tyrosine kinase domain mutation in addition to the established FLT3 internal tandem duplication. This detection prompted a therapeutic switch from quizartinib to gilteritinib. Subsequent genomic testing with the FoundationOne Heme panel characterized the specific tyrosine kinase domain alteration as an FLT3-D835V mutation.

Retrospective genomic analysis of serial patient samples clarified the timing of this resistance mutation. Researchers compared specimens obtained prior to starting quizartinib, before the second allogeneic transplantation, and at relapse during quizartinib maintenance. The evaluation confirmed that the FLT3-D835V mutation was absent in the two earlier specimens, indicating that the alteration arose during quizartinib maintenance therapy.

Following the switch to gilteritinib, the patient achieved complete remission without requiring donor lymphocyte infusions or additional intensive chemotherapy. The patient has remained in continuous remission for more than five years. The authors noted that the case illustrates the clinical utility of FLT3 testing for guiding salvage therapy and serial genomic profiling for characterizing mechanisms of relapse.

Subject of Research: Gilteritinib treatment for relapsed FLT3-mutated acute myeloid leukemia

Article Title: Durable remission for more than 5 years with gilteritinib in FLT3-ITD-positive acute myeloid leukemia relapsing after a second allogeneic transplantation

Article References: Katagiri, S., Moriyama, M., Yoshizawa, S., Chi, S., Minami, Y., & Akahane, D. (2026). Durable remission for more than 5 years with gilteritinib in FLT3-ITD-positive acute myeloid leukemia relapsing after a second allogeneic transplantation. Annals of Hematology. https://doi.org/10.1007/s00277-026-07347-9

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07347-9

Keywords: acute myeloid leukemia, gilteritinib, quizartinib, FLT3-ITD, FLT3-D835V, hematopoietic stem cell transplantation, drug resistance, hematology, Durable, remission, than, years