Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematologic malignancy, which often manifests with skin lesions in addition to lymph node, blood, and bone marrow involvement. Standard of care treatments for BPDCN patients are intense chemotherapy or tagraxofusp (Elzonris®). Although many patients initially respond to standard-of-care therapies, most will eventually relapse. Overexpression of CD123 (IL-3Rα receptor) is a hallmark of BPDCN thus making this antigen an attractive target.