Tagraxofusp

A treatment cycle is 28 days. Tagraxofusp will be administered at 9 mcg/kg IV over 15 minutes (-5 or +15 minutes) daily for 3 consecutive days (or 3 doses over a period not to exceed 10 days if postponement is required to allow for toxicity resolution), followed by azacitidine administered at 75 mg/m2 SQ or IV daily on Day 4 through Day 10. Venetoclax will begin on Day 4 and continue through Day 24 (21 consecutive days). A bone marrow biopsy (BM Bx) will be performed on Day 24 (+3 days) of Cycle 1. Subjects who do not achieve a CRm will proceed with the next cycle of Induction Phase study treatment, irrespective of hematologic laboratory values. Cycle 2+ will consist of tagraxofusp 9 mcg/kg IV over 15 minutes daily for 3 consecutive days (Day 1-3 or 3 doses over a period not to exceed 10 days if postponement is required to allow for toxicity resolution), azacitidine 75 mg/m2 SQ or IV on Day 1 through Day 7 or Days 1-7 or 1-5, 8-9 and venetoclax 400 mg daily Day 1 through Day 21. A bone marrow biopsy (BM Bx) will be performed on Day 21 (+3 days) of Cycle 2. If a CRm is obtained or maintained, the subject will move to or remain on the Continuation Phase. Subjects who do not achieve a marrow CR (CRm) after Cycle 2 will proceed with the next cycle of Induction Phase study treatment as described above, irrespective of hematologic laboratory values. If a CRm is obtained after Cycle 3 or 4, the subject will move to the Continuation Phase . If a CRm is not obtained after Cycle 4, study treatment will be discontinued and the subject will move to follow up. If per the investigator, the subject is receiving clinical benefit, study treatment may continue until toxicity or completion of 12 total cycles. A BM Bx will be performed at least every 3 cycles for these subjects.

The goal of this clinical trial is to study the efficacy of the tagraxofusp + venetoclax combination in treatment-naive blastic plasmacytoid dendritic cell neoplasm adult patients. The main question is to verify the response in patients after 3 cycles of tagraxofusp+venetolax and to demonstrate if the combination of tagraxofusp + venetoclax increases the rate of complete remission, assessed after 3 months of treatment. Patients will receive a ramp-up phase of venetoclax during 3 days and at least 3 cycles of venetoclax. After, the investigators will evaluate the response, and depending on the response observed, patients may receive additional cycles of treatment for a maximum of 24 cycles, or receive an allograft or discontinue the treatment in the case of therapeutic failure.