Tagraxofusp maintenance post-hematopoietic stem cell transplantation provides long-term survival and manageable safety for a patient with blastic plasmacytoid dendritic cell neoplasm.

Presented here is the case of a 68-year-old woman with blastic plasmacytoid dendritic cell neoplasm (BPDCN) treated with tagraxofusp (TAG) maintenance therapy post-allogeneic hematopoietic stem cell transplantation (allo-HCT). Prior to allo-HCT, the patient was treated with hydroxyurea and mini-CVD (cyclophosphamide, vincristine, and dexamethasone alternating with methotrexate (Methotrexate) and cytarabine) + venetoclax + TAG for 5 cycles, which induced morphologic complete remission with minimal residual disease. After allo-HCT, the patient had persistent cytogenic abnormalities 45,XX,der(7)add(7)(p13)del(7)(q11.2q22)add(7)(q32),add(12)(p13),-15,del(16)(q23),-17,+22,+2mar[1]/46,XX[19], and was then treated with TAG maintenance therapy at 9 mg/kg on a 28-day cycle for 16 cycles. At mid-treatment (cycle 6 of 16 cycles of TAG) and prior to TAG discontinuation (due to travel burden), the patient was negative for minimal residual disease and was in complete remission. There was no high-grade toxicity or capillary leak syndrome. The patient remains in complete remission as of present day (>17 months CR). This is the first case study illustrating the feasibility of long-term TAG maintenance post-allo-HCT to control BPDCN.