Accession Number
DB14731 / 8ZHS5657EH

Tagraxofusp is an IL-3 conjugated truncated diphtheria toxin.[L4895] it is composed by the catalytic and translocation domain names of diphtheria toxin fused thru Met-His linker to a full-duration human IL-3.[L4897, L4898] Tagraxofusp turned into developed through Stemline Therapeutics Inc and FDA authorized on December 21, 2018, because the first therapy for blastic plasmacytoid dendritic cell neoplasm.[L4894] This drug done approval after being designed with the name of step forward remedy, priority evaluation, and orphan drug repute.[L4893] Tagraxofusp has been designed as an orphan drug in ecu on account that November 2015.[L4898]



In vitro studies showed that BPDCN blasts are ultrasensitive to tagraxofusp by presenting IC50 values in the femtomolar scale.[L4897] One of the main physiological changes of BPDCN is the presence of elevated interferon alpha and to produce an inflammatory response. In trials with tagraxofusp and following cell depletion, there was observed a significant reduction in the levels of interferon alpha and interleukin 6.[L4896] In clinical trials, tagraxofusp reported complete remission and complete remission with a skin abnormality not indicative of active disease in 54% of the treated patients.[L4893]


Tagraxofusp is indicated for the treatment of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in adults and pediatric patients over 2 years old. This treatment allows an alternative for the previous intense treatment which consisted of intensive chemotherapy followed by bone marrow transplantation.[L4893] BPDCN is a rare hematologic malignancy derived from plasmacytoid dendritic cells. It is characterized by the significantly increased expression of cells expressing CD4/CD56/CD123 and other markers restricted to plasmacytoid dendritic cells and a lack of expression of lymphoid, natural killer or myeloid lineage-associated antigens.[A40274] A key feature of the malignant cells is the overexpression of CD123, also known as interleukin-3 receptor, and the constant requirement of IL-3 for survival.[L4897]


Tagraxofusp binds to cells expressing the IL-3 receptor and delivers in them the diphtheria toxin after binding. This is very useful as the malignant cells in BPDCN present a particularly high expression of IL-3 receptor (CD123+ pDC).[L4896] To be more specific, tagraxofusp gets internalized to the IL-3 receptor-expressing cell allowing for diphtheria toxin translocation to the cytosol and followed by the binding to ADP-ribosylation elongation factor 2 which is a key factor for protein translation. Once the protein synthesis is inhibited, the cell goes under a process of apoptosis.[L4895, L4897] As the apoptosis induction requires an active state of protein synthesis, tagraxofusp is not able to perform its apoptotic function in dormant cells.[L4897]