Flotetuzumab for the Treatment of Pediatric Recurrent or Refractory Acute Myeloid Leukemia

Inclusion Criteria: * Patients must weigh \>/= 17 kg * Weight limit is due to constraints related to the concentration of the current drug formulation. If a new formulation of flotetuzumab becomes available to allow dosing of smaller patients, the protocol will be amended. * Patients with recurrent or refractory AML are eligible. Patients must have histologic verification of malignancy at relapse. * Patients with leukemia must have \>/= M2 marrow by morphology and/or flow cytometry and one of the following: * Second or greater relapse * Refractory after 2 or more chemotherapy cycles * First relapse after primary chemotherapy-refractory disease * First relapse after hematopoietic stem cell transplantation (HSCT) * Central nervous system (CNS) disease: * Patients must have the status of CNS1 and no clinical signs or neurologic symptoms suggestive of CNS leukemia, such as cranial palsy. * Patients with CNS3 or CNS2 status may receive antecedent intrathecal chemotherapy to achieve CNS1 status prior to study entry. * Patients with a history of CNS chloromatous disease are required to have no radiographic evidence of disease prior to enrollment. * Patient's current disease state must be one for which there is no known curative therapy or therapy proven to prolong survival with an acceptable quality of life. * Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2. Use Karnofsky for patients \> 16 y…