Another CD123-targeting biotherapeutic agent associated with severe neutropenia is the human IL3 fusion toxin Tagraxofusb (SL-401) [53,54], which was approved by the FDA in 2018 for treatment of blastic plasmacytoid dendritic cell neoplasm (BPDCN), being found to be not very active in AML at the MTD of 12.5 mcg/kg/day (Clinicaltrial.gov identifier: NCT02270463). The gene discussed is IL3; the disease is acute myeloid leukemia.