GT Biopharma, Inc. announced the submission of an Investigational New Drug (IND) application with the US Food and Drug Administration (FDA) for the development of GTB-3650, a 2nd generation antibody TriKE for the treatment of patients with CD33+ leukemia, including relapsed/refractory acute myelogenous leukemia (AML) and high-risk myelodysplastic syndrome (MDS).