Of note, the CD123-directed therapy tagraxofusp has now become the standard of care (SoC) for blastic plasmacytoid dendritic cell neoplasm (BPDCN) (Pemmaraju NEJM 2019)...This new construct permits intermittent intravenous (IV) dosing due to a longer half-life (Alderson ASH 2021) compared with the first-generation DART molecule flotetuzumab, a continuous-infusion molecule that showed preliminary single-agent activity in refractory acute myeloid leukemia (AML) (Uy Blood 2021)...Secondary objectives include pharmacokinetics, immunogenicity, preliminary assessment of MGD024 clinical activity, and preliminary evaluation of safety/efficacy of tocilizumab in the management of MGD024-induced CRS...Response evaluation is determined using modified European LeukemiaNet (ELN) 2017 criteria for ALM and ALL; International Working Group (IWG) 2006 criteria for MDS; Lugano 2014 criteria for cHL; ELN 2020 criteria for CML; 2017 consensus criteria for HCL; IWG-Myeloproliferative Neoplasms Research and Treatment (MRT) & European Competence Network on Mastocytosis (ECNM) 2013 criteria for ASM; and modified criteria from Pemmaraju NEJM 2019 for BPDCN. Patients benefitting from MGD024 may continue to receive MGD024 after completion of the study treatment period, at physician discretion.
Introduction: Notwithstanding recent progress, acute myeloid leukemia (AML) remains an incurable disease, particularly in patients (pts) with relapsing/refractory disorder or ineligible for intensive induction therapy (unfit pts). Consistent with its decreased affinity for CD3, MGD024 demonstrated reduced in vitro potency in killing CD123-positive target cells compared to flotetuzumab or RES234M1.1, but proportionally greater reduction in cytokine release. MGD024, however, achieved maximal cytolytic activity as flotetuzumab or RES234M1.1, albeit at increased concentrations. Similarly, MGD024 showed reduced potency in vivo against CD123-positive tumors compared to RES234M1.1; nevertheless, tumor growth reduction of the same magnitude as that observed with RES234M1.1 was attained at higher doses of MGD024 (0.5-1 mg/kg IV 2QW MGD024 vs.