Safety and Efficacy of Expanded, Universal Donor Natural Killer Cells for Relapsed/Refractory AML

This is a phase I/II dose escalation study designed to determine the safety and estimate the efficacy of UD-NK cells combined with FLA chemotherapy in patients age 1-24.99 with relapsed or refractory acute myeloid leukemia. PRIMARY OBJECTIVE: I. To determine the safety and recommended phase II dose of adoptive NK cell therapy using UD-NK cells in pediatric and young adult patients with relapsed/refractory AML. SECONDARY OBJECTIVES: I. To estimate the efficacy of UD- NK cells with FLA chemotherapy in pediatric and young adult patients with relapsed/refractory AML. EXPLORATORY OBJECTIVES: I. To determine the immunophenotype and function of UD-NK cells II. To characterize in vivo expansion of UD-NK cells III. To determine the persistence of UD-NK cells Six doses of universal donor mbIL-21 expanded NK cells (UD-NK) given thrice weekly for two weeks. Days may vary and NK cells can be given from days 0 to 21. Patients may receive up to 2 cycles of fludarabine/cytarabine (FLA) + NK cells (up to 12 NK cell infusions) if they do not achieve CR after cycle 1 or if necessary to bridge to transplant.