AML SA expansion group : histologically or cytologically proven AML with a FLT ITD or TKD mutation previously determined by local testing that is R/R to standard therapy or for whom standard treatments are contraindicated AML SA expansion group : histologically or cytologically proven AML with intermediate or unfavorable risk cytogenetics in the absence of a detectable FLT ITD or TKD mutation as previously determined by local testing that is R/R to standard therapy or for whom standard treatments are contraindicated Participant has presence of the FLT/ITD activating mutation in the BM or PB as determined by the local institution at diagnosis. Newly diagnosed AML patients who are identified with FLT-ITD or tyrosine kinase domain (TKD) point mutation in the codon for an aspartate (D) or an isoleucine (I) residue FLT-ITD and/or FLT-D mutated patients with relapsed/refractory AML (any number of relapses) including patients who may have been previously exposed to one or more FLT-inhibitor therapies will be eligible for the phase I portion of this study Patients must be eligible for one of two cohorts: cohort (FLT and/or FLT-D inhibitor failure cohort) in FLT-ITD and/or FLT-D mutated relapsed/refractory AML who have failed therapy with up to two prior salvage regimens (stem cell transplant [SCT] or stem cell therapy for patients who previously underwent SCT/stem cell therapy in remission will not be considered a salvage regimen) and have previously been exposed at least one prior FLT inhibitor; cohort (FLT inhibitor naive cohort) in FLT-ITD and/or FLT-D mutated relapsed/refractory who have failed therapy with up to two prior salvage regimens (SCT or stem cell therapy for patients who previously underwent SCT/stem cell therapy in remission will not be considered a salvage regimen) with no prior exposure to any FLT inhibitor FLT-ITD or FLT-D positive disease at any time during disease course. For Phase I Only: Patients are eligible regardless of their FLT mutation status. For Phase II only: Patients must have evidence of FLT ITD in their most recent assessment. FLT mutation positive (ITD, TKD or other) Has FLT-ITD mutant (> % FLT-ITD/total FLT) AML (primary AML or secondary to myelodysplastic syndrome [MDS]) that have failed any prior induction therapy regimen or have relapsed after prior induction/consolidation therapy, have not received more than one salvage therapy, and have not received more than one FLT inhibitor during prior AML treatment(s) FLT-ITD mutant (> % FLT-ITD/total FLT) AML (primary AML or secondary to MDS) is ineligible for intensive induction chemotherapy by meeting at least of the protocol-defined criteria Presence of FLT-ITD and/or D mutation(s) in bone marrow or peripheral blood Presence of FLT-ITD and/or D mutation(s) Patients with and without FLT mutations will be eligible to participate Subject is positive for FLT mutation in bone marrow or whole blood as determined by the central lab. A subject with rapidly proliferative disease and unable to wait for the central lab results can be enrolled based on a local test performed after completion of the last interventional treatment. Subjects can be enrolled from a local test result if they have any of the following FLT mutations: FLT internal tandem duplication (ITD), FLT tyrosine kinase domain (TKD)/D or FLT- TKD/I. Subject has an FLT mutation other than the following: FLT-ITD, FLT-TKD/D or FLT-TKD/I. Presence of the FLT-ITD activating mutation in bone marrow or peripheral blood (allelic ratio as determined by a central laboratory with a cutoff of ?% FLT-ITD/total FLT). If a specimen has been sent for FLT-ITD testing at the central laboratory but the subject requires treatment for AML before the central FLT-ITD test result is available, a local test result may be acceptable for randomization after consultation with the Medical Monitor. Prior treatment with a FLT targeted therapy including sorafenib or investigational FLT inhibitors (not including the multi-kinase inhibitor, midostaurin). Subjects must have tested positive for FLT-ITD and/or other FLT activating mutations Subject is positive for FLT mutation (internal tandem duplication [ITD] or tyrosine kinase domain [TKD] [D/I] mutation) in bone marrow or whole blood as determined by central laboratory. Note: Only applicable to the randomization portion. Untreated, histological confirmed acute myeloid leukemia (AML) based on World Health Organization (WHO) criteria with either/or both:\r\n* FLT ITD mutation\r\n* FLT TKD mutation Administration of the radioisotope, -FLT, which is being concurrently investigated on an imaging study within the Pediatric Brain Tumor Consortium (PBTC), is allowed > hours prior to initiation of pomalidomide on this study; any adverse events related to the FLT must have resolved completely Confirmed FLT-ITD mutation, measured on peripheral blood or bone marrow aspirate prior to study enrollment (patients may also have a concurrent FLT-tyrosine kinase domain [TKD] mutation) Patients must have tested positive for FLT-ITD and /or other FLT activating mutations within day screening period Absence of a FLT activating mutation Assessment of FLT mutation status; Cohort A: Subjects with a FLT mutation (e.g. ITD or D) with prior FLT inhibitor treatment Cohort B: Subjects with a FLT mutation (e.g. ITD or D) without prior FLT inhibitor treatment Cohort C: Subjects without a FLT mutation at the time of enrollment Poor-risk (monosomy ,) or complex cytogenetics profile ( or more cytogenetic abnormalities), or deletion of chromosome (-), or deletion of chromosome (-), or positive FLT-ITD mutation Participant disease tested positive for FLT-ITD or TKD within -day screening period Positive for Flt-ITD activating mutations during Screening. Local laboratory results must be received prior to enrollment. Patients with a history of Flt-ITD positive disease may be considered after discussion with the Medical Monitor. Patients should have a FLT mutation, either internal tandem duplication (ITD) or kinase domain mutation or activation loop mutation Presence of FLT-ITD activating mutation in bone marrow (allelic ratio of ?% FLT-ITD/total FLT); Prior treatment with quizartinib or other FLT-ITD inhibitors; Patients must have a documented FLT ITD mutation, determined by local laboratory for eligibility (historical tissue will be requested for central analysis confirmation) Patients requiring emergency surgical intervention that would be inappropriately delayed by FLT-PET imaging Agreed to FLT-PET imaging and signed consent and eligible FLT-PET protocol - Subject has had presence of the FLT/ITD activating mutation in the bone marrow or peripheral blood as determined by the local institution at diagnosis. Be a candidate for [F]FLT PET imaging