How do you treat blastic plasmacytoid dendritic cell neoplasm?

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Richard A. Larson, MD
Professor of Medicine at the University of Chicago in Chicago, Illinois

This month, Richard A. Larson, MD, answers a question about the treatment of blastic plasmacytoid dendritic cell neoplasm.


The patient is a 73-year-old man with blastic plasmacytoid dendritic cell neoplasm and a long history of anemia. A bone marrow biopsy three years ago showed only iron deficiency and a gastrointestinal evaluation was unremarkable. The patient received iron replacement therapy, but his anemia never improved. He now presents with purple skin lesions.

A biopsy showed blastic plasmacytoid dendritic cell neoplasm, and a bone marrow biopsy showed very cellular bone marrow with 60 to 70 percent blastic plasmacytoid dendritic cell neoplasm. Results from a cytogenetic analysis are pending. Meanwhile, he has been relatively asymptomatic. He is active and healthy and his blood count has been stable for the last three years (white blood cell count is 3.3 x 109/L, hemoglobin count is 10.3 g/dl, and platelet count is 135 x 109/L). He is also worried about toxicities with acute lymphocytic leukemia (ALL)–type treatment.

How would you treat this patient? What result can you expect from treatment?


This is a very uncommon disorder. The disease itself can have a variable rate of progression, but it generally leads to bone marrow failure and death. The malignant cells are typically resistant to usual leukemia or lymphoma chemotherapy regimens; although remissions can be achieved, they are short in duration.

The majority of patients who have achieved long-term survival have had an allogeneic transplant, usually early in first remission, and children have better outcomes than older patients.
Typically, we initiate therapy with an ALL regimen appropriate for patients of the same age. For your patient, this might include vincristine, dexamethasone, and daunorubicin, with or without cyclophosphamide.

Many older patients do not tolerate asparaginase well, which we prefer to use in younger patients with ALL. If the initial treatment is unsuccessful, then we often switch to a high-dose cytarabine regimen. Others use a chemotherapeutic AML regimen such as 7+3. I am not aware of therapy with azacitidine or decitabine for blastic plasmacytoid dendritic cell neoplasm, but I suspect this approach has been tried.

There also may be a clinical trial available to your patient. Recently, there were some encouraging data published in Blood about an anti-CD123 immunotoxin in this disease, which represented the first prospective study of treatment of patients with blastic plasmacytoid dendritic cell neoplasm.1 In this study, 11 patients were treated with a single course of SL-401 at 12.5 μg/kg intravenously over 15 minutes daily for up to five doses; three patients who had initial responses to SL-401 received a second course in relapse. Seven of the nine evaluable (78%) patients had major responses after a single course of SL-401, and the median duration of responses was five months. The most common adverse events including fever, chills, hypotension, edema, hypoalbuminemia, thrombocytopenia, and transaminasemia were transient.


  1. Frankel AE, Woo JH, Ahn C, et al. Activity of SL-401, a targeted therapy directed to interleukin-3 receptor, in blastic plasmacytoid dendritic cell neoplasm patients. Blood. 2014 Jul;124:385-92.

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