Researchers are learning more about genetic aberrations common in the rare but clinically aggressive hematological cancer blastic plasmacytoid dendritic cell neoplasm. There is one targeted therapy approved by the U.S. Food and Drug Administration: Elzonris (tagraxofusp-erzs, Stemline). However, more treatment options are needed to improve the cancers clinical outcome, according to a review published May 2020 in Critical Reviews Oncology/Hematology.1

Dermatologists might be the first providers to encounter patients with blastic plasmacytoid dendritic cell neoplasm because more than 70% of these patients have cutaneous lesions. Those lesions often are asymptomatic and vary in size. The skin lesions tend to have nodules, plaques or bruise-like areas, a brown to violet color and might be solitary or multifocal, according to the authors.

Blastic plasmacytoid dendritic cell neoplasm often originates from type 2 myeloid-derived resting plasmacytoid dendritic cell precursors. Recent research suggests providers can diagnose the cancer when patients express at least four of five plasmacytoid dendritic cell specific markers, CD4, CD56, CD123, TCL1 and BDCA-2, without expressing myeloid, T-cell or B-cell lineage markers.

Commonly, [blastic plasmacytoid dendritic cell neoplasm] is characterized by high CD123 expression, aberrant NF-B [nuclear factor-B] activation, dependence on TCF4-/BRD4-network, and deregulated cholesterol metabolism, they wrote.

Despite advancing knowledge about the cancer type, patients median overall survival remains at 12 to 14 months, according to the paper. Conventional treatment approaches include chemotherapy, radiotherapy and ultimately hematopoietic stem cell transplantation. The challenges with conventional therapies are while blastic plasmacytoid dendritic cell neoplasm is sensitive to some chemotherapy regimens, patient relapse is high at more than 60%. And many patients with blastic plasmacytoid dendritic cell neoplasm are too old or frail to have intensive chemotherapy or hematopoietic stem cell transplantation, according to the authors.

Recently, the most attractive agent for [blastic plasmacytoid dendritic cell neoplasm] is tagraxofusp, which is composed of the catalytic and translocation domains of diphtheria toxin (DT) fused to interleukin-3 (IL-3), the authors wrote.

Blastic plasmacytoid dendritic cell neoplasm cells overexpress interleukin-3 receptor subunit alpha (IL3RA, also called CD123). Elzonris, or tagraxofusp-erzs, is a CD123-directed cytotoxin given intravenously, which is used to treat blastic plasmacytoid dendritic cell neoplasm in adults and in pediatric patients 2 years and older.

Researchers reported in a study of 47 blastic plasmacytoid dendritic cell neoplasm patients published in 2019 in the New England Journal of Medicine that tagraxofusp led to clinical responses in untreated and relapsed patients.2 The overall response rate with tagraxofusp was 90% and the primary outcome of complete response and clinical complete response was 72% among the previously untreated patients. Overall response was 67% in the previously treated patients. Serious adverse events including capillary leak syndrome, hepatic dysfunction and thrombocytopenia were common, according to the NEJM paper.

More targeted therapies are needed to treat blastic plasmacytoid dendritic cell neoplasm, but many potential therapeutic agents are not advancing to clinical trials, according to authors of the paper in Critical Reviews Oncology/Hematology.

Common blastic plasmacytoid dendritic cell neoplasm characteristics are genetically heterogeneous and provide valuable drug targets, according to the authors.

Apart from aberrant activation of NF-B signaling pathway, which is highly dependent on TCF4- and BRD4- transcriptional networks, cholesterol metabolism deregulation and CD123 expression, defects of DNA damage repair and mitosis are new, potential common features of the cancer. Corresponding therapies might be promising, the authors wrote.

Venetoclax, anti-CD123 CAR-T, XmAb14045 and IMGN632 are in clinical trials for blastic plasmacytoid dendritic cell neoplasm. But the authors noted that bortezomib, lenalidomide, 5-aza and pralatrexate could easily be pushed to the front line of the cancers treatment.

Disclosures:

The authors report no relevant disclosures.

References:

1. Zhang X, Sun J, Yang M, Wang L, Jin J. New perspectives in genetics and targeted therapy for blastic plasmacytoid dendritic cell neoplasm. Crit Rev Oncol Hematol. 2020 May;149:102928.2. Pemmaraju N, Lane AA, Sweet KL, et al. Tagraxofusp in Blastic Plasmacytoid Dendritic-Cell Neoplasm. N Engl J Med. 2019;380(17):1628-1637.

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Genetic features pave way for targeted BPDCN therapies - Dermatology Times