{"entity":{"id":"flt3-itd","kind":"biomarker","name":"FLT3-ITD (internal tandem duplication)","aka":["FLT3-ITD","FLT3 ITD","FLT3 internal tandem duplication","FLT3-ITD positive","FLT3-ITD allelic ratio","ITD-positive AML"],"tldr":"FLT3-ITD is a duplicated stretch of the FLT3 receptor gene found in about a quarter of acute myeloid leukaemias; it makes relapse more likely and is treated with midostaurin, quizartinib or gilteritinib.","summary":"Internal tandem duplications in the juxtamembrane domain are detected by PCR fragment analysis (the LeukoStrat CDx FLT3 Mutation Assay reports ITD and the TKD mutations D835 and I836) or by sequencing; the allelic ratio once used in ELN risk stratification was dropped in ELN 2022. Midostaurin (Rydapt) is labelled for newly diagnosed FLT3 mutation-positive AML with induction and consolidation chemotherapy; quizartinib (Vanflyta, 2023) specifically for FLT3-ITD-positive newly diagnosed AML including maintenance; gilteritinib (Xospata) for relapsed or refractory AML with a FLT3 mutation. All three name an FDA-approved test, and the LeukoStrat assay is the companion diagnostic for each.","asOf":"2026-09-23","links":[{"label":"VANFLYTA prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=29cdbcfe-497d-4e78-bb7b-2d4acafe8e86"},{"label":"RYDAPT prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=11fa3fc9-6776-49a6-b1c1-653f627c3e58"}],"tags":["biomarker","flt3"],"related":["flt3-tkd","npm1-mutation"],"cancers":["aml","aml-flt3"],"sections":[],"technologies":[],"targets":[],"drugs":["midostaurin","quizartinib","gilteritinib"],"companies":[],"institutions":[],"pathways":[],"terms":["flt3-itd-allelic-ratio"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"flt3","measurement":"sequencing-variant","scoringRule":{"text":"An internal tandem duplication in FLT3 exons 14 to 15 detected by PCR fragment analysis (LeukoStrat CDx) or sequencing of blood or marrow; the assay's positivity uses a signal ratio cut-off of 0.05.","quote":"ITD mutations and TKD mutations D835 and I836","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools","sourceLabel":"FDA: List of FDA-Authorized Companion Diagnostic Devices"},"thresholds":[{"value":"FLT3-ITD-positive","drugId":"quizartinib","cancerId":"aml-flt3","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=29cdbcfe-497d-4e78-bb7b-2d4acafe8e86","quote":"VANFLYTA is indicated in combination with standard cytarabine and anthracycline induction and cytarabine consolidation, and as maintenance monotherapy following consolidation chemotherapy, for the treatment of adult patients with newly diagnosed acute myeloid leukemia (AML) that is FLT3 internal tandem duplication (ITD)-positive as detected by an FDA-approved test","status":"current"},{"value":"FLT3 mutation-positive (ITD or TKD)","drugId":"midostaurin","cancerId":"aml-flt3","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=11fa3fc9-6776-49a6-b1c1-653f627c3e58","quote":"Newly diagnosed acute myeloid leukemia (AML) that is FLT3 mutation-positive as detected by an FDA-approved test, in combination with standard cytarabine and daunorubicin induction and cytarabine consolidation.","status":"current"},{"value":"FLT3 mutation (ITD or TKD), relapsed or refractory","drugId":"gilteritinib","cancerId":"aml-flt3","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b5ff59aa-9c0d-49a8-9053-1f179b482383","quote":"XOSPATA is a kinase inhibitor indicated for the treatment of adult patients who have relapsed or refractory acute myeloid leukemia (AML) with a FLT3 mutation as detected by an FDA-approved test.","status":"current"}],"tests":["foundationone-heme","neotype-profiles"],"assays":["flt3-leukostrat"],"companionDiagnostics":[{"device":"LeukoStrat CDx FLT3 Mutation Assay","maker":"Invivoscribe Technologies","drugs":["midostaurin"],"indication":"Acute Myelogenous Leukemia - Peripheral Blood or Bone Marrow","pma":"P160040 (04/28/2017)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"LeukoStrat CDx FLT3 Mutation Assay","maker":"Invivoscribe Technologies","drugs":["gilteritinib"],"indication":"Acute Myelogenous Leukemia - Peripheral Blood or Bone Marrow","pma":"P160040/S002 (11/28/2018)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"LeukoStrat CDx FLT3 Mutation Assay","maker":"Invivoscribe Technologies","drugs":["quizartinib"],"indication":"Acute Myeloid Leukemia (AML) - Peripheral Blood or Bone Marrow","pma":"P160040/S011 (07/20/2023)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"}],"forPatient":"A FLT3-ITD result at diagnosis means a FLT3 inhibitor (midostaurin or quizartinib) is added to chemotherapy from the first cycle, and it strengthens the case for a stem cell transplant in first remission. If the leukaemia comes back, gilteritinib tablets are on label. The test must be back within days, so ask that it be sent at diagnosis."},"route":"/biomarkers/flt3-itd/","neighbours":{"biomarker":[{"id":"cd33-expression","kind":"biomarker","name":"CD33 expression (CD33-positive)","route":"/biomarkers/cd33-expression/"},{"id":"flt3-tkd","kind":"biomarker","name":"FLT3-TKD (D835 and I836 tyrosine kinase domain mutations)","route":"/biomarkers/flt3-tkd/"},{"id":"npm1-mutation","kind":"biomarker","name":"NPM1 mutation","route":"/biomarkers/npm1-mutation/"}],"cancer":[{"id":"aml","kind":"cancer","name":"Acute myeloid leukaemia","route":"/cancers/aml/"},{"id":"aml-flt3","kind":"cancer","name":"FLT3-mutated acute myeloid leukaemia","route":"/cancers/aml-flt3/"}],"drug":[{"id":"gilteritinib","kind":"drug","name":"Gilteritinib","route":"/drugs/gilteritinib/"},{"id":"midostaurin","kind":"drug","name":"Midostaurin","route":"/drugs/midostaurin/"},{"id":"quizartinib","kind":"drug","name":"Quizartinib","route":"/drugs/quizartinib/"}],"term":[{"id":"flt3-itd-allelic-ratio","kind":"term","name":"FLT3-ITD allelic ratio","route":"/terms/flt3-itd-allelic-ratio/"}],"target":[{"id":"flt3","kind":"target","name":"FLT3","route":"/targets/flt3/"}]}}