Epidemiology and survival of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm: a Swiss case series of a very rare disease and a structured review of the literature

INTRODUCTION

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a very rare disease, with unique diagnostic challenges and often dismal outcome. There are no widely accepted treatment guidelines available. Lymphoma-like regimens with or without autologous or allogenic transplantation were the cornerstone of most therapeutic concepts. A few years ago, the CD123-directed immunoconjugate tagraxofusp emerged as a new valuable treatment option. The goal of our research was to collect available data on BPDCN-patients treated at large centres in Switzerland and worldwide and to draw conclusions regarding the incidence, clinical presentation, prognostic factors and therapeutic strategies.

METHODS

We collected data from BPDCN patients from leading Swiss haemato-oncology centres from 2005 to 2022. Furthermore, we reviewed and analysed the published literature (cohorts and case reports in peer-reviewed journals) from 1997 to 2020 (structured review of the literature).

RESULTS

We identified 115 international publications including 600 patients from all over the world. Most of them had very small sample sizes (only ten papers with more than ten patients) and all but one were retrospective or observational respectively. Most included patients were Europeans (n = 385, 64%) and Asians (n = 120, 20%), followed by Americans (n = 90, 15%) and patients from Australia/New Zealand (n = 3) and Africa (n = 2). BPDCN was more common in men with a predominance of 3:1. The median age (n = 414) at diagnosis was 66.5 years ranging from one month to 103 years. Newly diagnosed women were significantly younger than men (median: 62 vs 67 years, mean: 53.4 vs 59.3 years, p = 0.027) and less often had bone marrow infiltration and affected lymph nodes. Upfront allogenic transplantation as well as ALL regimens performed best, with response to first-line therapy clearly associated with better overall survival. The Swiss cohort contained 26 patients (23 males and 3 females) over 18 years (2005-2022). The median age at diagnosis was 68.5 years (range: 20-83). Ten patients underwent upfront stem cell transplantation (seven allogenic and three autologous), at least trending towards a better overall survival than other therapies. With a follow-up of 8 years, the median overall survival was 1.2 years. Eight patients in this cohort were treated with tagraxofusp, which became available in 2020 and was approved by Swissmedic in 2023.

CONCLUSIONS

Our study confirms that BPDCN is a very rare and difficult-to-treat disease. Underdiagnosis and underreporting in the literature pose further challenges. Symptoms at presentation seem to differ slightly between sexes and reaching a complete remission after first-line treatment remains crucial for a prolonged overall survival. Effective treatment protocols in first line include transplantation regimens (mainly allogenic, potentially also autologous) as well as ALL protocols. In order to understand the significance of tagraxofusp as a bridge to transplant or as a continuous monotherapy in elderly patients, further evaluation with longer follow-up periods is required. In general, analysis of the Swiss patients confirmed the results from the worldwide cohort.

Diagnostic approach to blastic plasmacytoid dendritic cell neoplasm: historical perspectives and current understanding

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy composed of immature cells that exhibit plasmacytoid dendritic cell (pDC) differentiation. The diagnosis of BPDCN is often challenging due to its rarity and morphologic and phenotypic overlap with other hematologic malignancies, such as acute myeloid leukemia (AML). The emergence of tagraxofusp, a CD123-directed cytotoxin, and other novel therapies has underscored the importance of accurately diagnosing BPDCN. This review initially outlined the clinical and histopathological features of BPDCN, including patients with immunoblastoid morphology. Various proposed diagnostic criteria based on flow cytometry and immunohistochemistry findings were presented, highlighting critical points of caution in the diagnostic process. Strategies for detecting minimal residual disease or microinvasion in BPDCN, a significant clinical issue, were also discussed. Additionally, we reviewed the recurrent 8q24 (MYC) and MYB rearrangements observed in BPDCN, which can aid in diagnosis. Furthermore, we explored mature plasmacytoid dendritic cell proliferation (MPDCP) associated with myeloid neoplasm, which is characterized by a clonal proliferation of pDCs in cases with a defined myeloid neoplasm and may also serve as a potential differential diagnosis for BPDCN. Lastly, we discussed pDC-AML, characterized by pDC proliferation in AML cases, which can also be part of MPDCP and is often associated with frequent RUNX1 mutations. Overall, this review provides insights into BPDCN diagnosis and highlights the current challenges in its detection and differential diagnosis.

BPDCN: state of the art

The emergence of blastic plasmacytoid dendritic cell neoplasm (BPDCN) as its own distinct entity within the pantheon of hematologic malignancies is due to the growing understanding of its unique multiorgan clinical presentation and characteristic skin lesions. The occurrence of BPDCN is generally heralded by a multicompartmental presentation of violaceous cutaneous lesions, involvement by bone marrow and/or blood, lymph node invasion, and an inclination toward extramedullary organ involvement, including, most remarkably, central nervous system (CNS)/cerebrospinal fluid positivity. With a median age historically of ≥ 70 years and up to 5:1 male predominance in most of the field's earlier studies, the most notable development in the modern era is the recognition of emerging important groups with BPDCN, such as female, pediatric, and adolescent/young adult patients; CNS + BPDCN patients; and an increasing number of cases being diagnosed worldwide. These trends are in line with the increased educational and research efforts, greater international collaboration, and markedly improved diagnostic tools and clinical approaches among hematology/oncology, hematopathology, dermatology, and dermatopathology teams around the world. Now, with over 5 years since the first commercially approved targeted agent specifically dedicated for BPDCN, the CD123-targeted agent tagraxofusp, improvements have been demonstrated particularly in the frontline setting for patients with BPDCN. The field is abundant with hope, as it has experienced advancements including greater molecular characterization, expanded identification of potential targets for therapy beyond CD123, advent of combination therapies, improving parameters for stem cell transplantation, and novel clinical trials specifically available for patients with BPDCN.

Advancing the understanding and management of blastic plasmacytoid dendritic cell neoplasm: Insights from recent case studies

We specifically discuss the mechanisms of the pathogenesis, diagnosis, and management of blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare but aggressive haematologic malignancy characterized by frequent skin manifestations and systemic dissemination. The article enriches our understanding of BPDCN through detailed case reports showing the clinical, immunophenotypic, and histopathological features that are critical for diagnosing this disease. These cases highlight the essential role of pathologists in employing advanced immunophenotyping techniques to accurately identify the disease early in its course and guide treatment decisions. Furthermore, we explore the implications of these findings for management strategies, emphasizing the use of targeted therapies such as tagraxofusp and the potential of allogeneic haematopoietic stem cell transplantation in achieving remission. The editorial underscores the importance of interdisciplinary approaches in managing BPDCN, pointing towards a future where precision medicine could significantly improve patient outcomes.

Unveiling the Tempest: Dermal Plasmacytoid Dendritic Cell Proliferation as the Harbinger of Acute Myeloid Leukemia

ABSTRACT

Plasmacytoid dendritic cell neoplasms are rare neoplasms originating from plasmacytoid dendritic cells (pDCs). They are subclassified into 2 types: blastic plasmacytoid dendritic cell neoplasm and mature plasmacytoid dendritic cell proliferation. Neoplastic expansion of pDCs has also been found to be associated with myeloid neoplasia. We present the diagnostically challenging case of a 62-year-old woman who presented to the emergency department with numerous hemorrhagic nodules and papules on the face and extensor surfaces near the elbows and neutropenic fevers. The patient had a history notable for lupus erythematosus and a recently performed excisional lymph node biopsy involved by a "plasmacytoid dendritic cell proliferation." A punch biopsy was performed, which showed a robust dermal infiltrate of atypical intermediate-sized mononuclear cells. The infiltrate was positive for CD4, CD43, and CD123. CD3 and CD8 highlighted background T cells. The infiltrate was negative for CD10, CD34, CD56, CD68, CD117, myeloperoxidase, lysozyme, TdT, and TCL-1. The findings favored a diagnosis of cutaneous involvement of the plasmacytoid dendritic cell proliferation. Given the association with acute leukemias, a subsequent bone marrow biopsy was recommended. The bone marrow biopsy was performed, which showed increased blasts (68% on a 500 differential cell count). Furthermore, immunohistochemical stains were performed, which highlighted the blasts to be positive for CD34 and BEST (alpha-naphthyl butyrate esterase) cytochemical stain. This diagnosis was consistent with bone marrow involvement of acute myelomonocytic leukemia. Given the overlapping presenting symptoms (skin lesions, adenopathy, marrow involvement) of pDC neoplasms and myeloid neoplasia and the possibility of presenting concurrently, increased awareness is of pivotal importance to help prevent potential misdiagnosis, missed diagnosis, and prompt investigation of possible associated neoplasms.

Overcoming Tagraxofusp-Erzs Monotherapy Resistance in Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) in a Real-World Clinical Setting

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and clinically aggressive hematologic malignancy with limited treatment options. Currently, standard treatment strategies include clinical trials; chemotherapy regimens such as hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (HCVAD); and tagraxofusp-erzs (TAG, previously SL-401) which is the first-in-class targeted therapy against CD123. TAG received Food and Drug Administration approval for frontline BPDCN treatment in December 2018 and has increasingly become an alternative to chemotherapy, offering potentially more effective and less toxic options. However, despite promising results, there are still patients who may be resistant to TAG monotherapy and/or who respond but eventually relapse. Herein, we discuss an important patient case of BPDCN treated with TAG and review BPDCN treatment strategies.

Venetoclax combined with azacitidine in blastic plasmacytoid dendritic cell neoplasm: a case report and comprehensive review on the current and future treatment

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare hematological malignancy with a highly aggressive behavior and median survival of <2 years. Especially, most BPDCN patients present with extensive and non-specific skin lesions, usually leading to misdiagnosis as a skin disease and delay therapy. As for treatment, most patients with BPDCN experience relapse shortly after treatment with the traditional regimens. The alleviation of skin symptoms reflects the effects of clinical treatments. Herein, we report a case of a 71-year-old man with intermittent and gradually expanding skin lesions over his chest, abdomen, and back for 1 year. On admission, physical examination revealed extensive skin lesions and multiple enlarged lymph nodes. Laboratory examinations showed pancytopenia and numerous malignant cells in the peripheral blood smear (60%), bone marrow aspirate smear (73.5%). Immunophenotyping using flow cytometry and immunohistochemistry presented large numbers of BPDCN cells in the bone marrow, cervical lymph nodes and dermal tissue. PET/CT revealed multiple enlarged lymph nodes and splenomegaly. Once the diagnosis was identified as BPDCN, the patient began treatment with the oral BCL2 inhibitor venetoclax and subcutaneously administered azacitidine. After the first course, skin lesions reduced markedly and complete remission was achieved in the bone marrow. Our study and current cumulative data according to reviewing systematically suggest that venetoclax combined with azacitidine is safe, effective, and applicable in the treatment of BPDCN, especially for elderly relapsed/refractory patients. This study, therefore, significantly contributes to the literature on the current and future treatment for BPDCN.

A systematic literature review of 74 Chinese blastic plasmacytoid dendritic cell neoplasm patients

Background

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological cancer. Due to its low incidence, researchers struggle to gather sufficient prospective data to inform clinical treatment.

Objectives

We sought to summarize the clinical characteristics and current treatment methods of BPDCN and provide more specific guidance on treatment options.

Design

A systematic literature review using data from 74 Chinese BPDCN patients.

Date resources and methods

We retrospectively analyzed the clinical manifestations, treatment response, survival outcomes, and prognostic factors of six BPDCN patients treated at the First Affiliated Hospital of Zhengzhou University and 68 patients described in 28 articles published in the China Knowledge Network database since 2019.

Results

In Chinese patients, the disease occurred with a male-to-female ratio of 2.52 and a median age of onset of 50 years in adults and 10 years in pediatric patients. Immunohistochemical analysis revealed distinctive immune phenotypes of BPDCN cells, characterized by high expression levels of CD4, CD56, CD123, and HLA-DR, while showing minimal to no expression of myeloperoxidase (MPO), CD20, and CD79a. There was no significant difference in the initial complete remission (CR) rate, relapse rate, and the overall survival (OS) time of patients receiving acute myeloid leukemia-like, acute lymphocytic leukemia-like, or non-Hodgkin's lymphoma-like chemotherapy regimens. Univariate analysis identified CD3 expression, male gender, and central nervous system infiltration as hazardous factors. In multivariate analysis, age proved to be an independent prognostic indicator, indicating better prognosis and longer OS time in younger patients. Notably, hematopoietic stem cell transplantation (HSCT) emerged as a significant factor in improving the survival outcomes for individuals diagnosed with BPDCN. However, further investigation is needed to explore the role of HSCT and the best timing for its implementation in pediatric BPDCN patients.

Conclusion

Administering HSCT during the initial CR state following inductive chemotherapy might extend the OS and improve the prognosis of patients with BPDCN.

Blastic Plasmacytoid Dendritic Cell Neoplasm Developed in Chronic Myeloid Leukemia in Molecular Remission During a Four-Year Treatment-Free Interval After Six Years of Dasatinib Treatment

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy affecting multiple sites, most commonly the skin. About 10-20% of BPDCN cases are accompanied by hematological neoplasms. A 71-year-old male was diagnosed with chronic myeloid leukemia in the chronic phase (CML-CP) 11 years prior (at 60 years of age), and dasatinib treatment was initiated. A major molecular response (MMR) was achieved 18 months after diagnosis, and the molecular response (MR)4.0 lasted beyond 36 months. Due to pancytopenia, dasatinib was discontinued at 74 months, but the CML-CP remained undetectable. One hundred and twenty-two months after the diagnosis, the patient presented with cutaneous lesions on the forehead and abdomen. Immunological and histological analyses of the skin biopsy showed infiltration of atypical cells from the deep epidermis to the entire dermis, expressing clusters of differentiation (CD) 4, CD56, and CD123 without any other markers. The same cells were observed in bone marrow samples. BPDCN was diagnosed, followed by chemotherapy and possibly autologous or allogeneic hematopoietic stem cell transplantation (HSCT). To the best of our knowledge, this is the first case report of the development of BPDCN in a patient with CML in molecular remission. Further studies are required to clarify the pathogenesis of BPDCN in patients with hematological malignancies in remission.

Simultaneous blastic plasmacytoid dendritic cell neoplasm and myelofibrosis: A case report

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare and aggressive tumor with an unknown pathogenesis. Myelofibrosis (MF) is a type of myeloproliferative neoplasm. MF can be secondary to several hematological malignancies, including chronic myeloid leukemia, myelodysplastic syndrome and hairy cell leukemia. In the present report, a rare case of BPDCN secondary to MF is described. A 70-year-old male patient developed a large purplish-red rash with recurrent symptoms. BPDCN was confirmed by immunohistochemistry of a biopsy specimen and flow cytometry of bone marrow cells. Bone marrow histopathology revealed MF. Next-generation sequencing of peripheral blood revealed mutations in the Tet methylcytosine dioxygenase 2 and NRAS proto-oncogene GTPase genes. The patient underwent one cycle of chemoimmunotherapy, but the condition progressed, an infection developed and the patient eventually died. The present case suggests that BPDCN can occur in conjunction with MF and that the prognosis of such patients is poor. Pathological examination and genetic testing aided in the diagnosis and treatment. This case emphasizes the need to raise awareness of BPDCN among clinicians and to be alert to the potential for fatal infection in patients with BPDCN combined with MF following myelosuppression triggered during chemotherapy.

Recent Advances in the Biology and CD123-Directed Treatment of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive myeloid malignancy of the dendritic cell lineage that affects patients of all ages, though the incidence appears to be highest in patients over the age of 60 years. Diagnosis is based on the presence of plasmacytoid dendritic cell precursors expressing CD123, the interleukin-3 (IL-3) receptor alpha, and a distinct histologic appearance. Timely diagnosis remains a challenge, due to lack of disease awareness and overlapping biologic and clinical features with other hematologic malignancies. Prognosis is poor with a median overall survival of 8 to 14 months, irrespective of disease presentation pattern. Historically, the principal treatment was remission induction therapy followed by a stem cell transplant (SCT) in eligible patients. However, bridging to SCT is often not achieved with induction chemotherapy regimens. The discovery that CD123 is universally expressed in BPDCN and is considered to have a pathogenetic role in its development paved the way for the successful introduction of tagraxofusp, a recombinant human IL-3 fused to a truncated diphtheria toxin payload, as an initial treatment for BPDCN. Tagraxofusp was approved in 2018 by the United States Food and Drug Administration for the treatment of patients aged 2 years and older with newly diagnosed and relapsed/refractory BPDCN, and by the European Medicines Agency in 2021 for first-line treatment of adults. The advent of tagraxofusp has opened a new era of precision oncology in the treatment of BPDCN. Herein, we present an overview of BPDCN biology, its diagnosis, and treatment options, illustrated by clinical cases.

Treatment of patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN): focus on the use of tagraxofusp and clinical considerations

BPDCN is an aggressive myeloid malignancy with a poor prognosis. It derives from the precursors of plasmacytoid dendritic cells and is characterized by CD123 overexpression, which is seen in all patients with BPDCN. The CD123-directed therapy tagraxofusp is the only approved treatment for BPDCN; it was approved in the US as monotherapy for the treatment of patients aged ≥2 years with treatment-naive or relapsed/refractory BPDCN. Herein, we review the available data supporting the utility of tagraxofusp in treating patients with BPDCN. In addition, we present best practices and real-world insights from clinicians in academic and community settings in the US on how they use tagraxofusp to treat BPDCN. Several case studies illustrate the efficacy of tagraxofusp and discuss its safety profile, as well as the prevention, mitigation, and management of anticipated adverse events.

Efficacy and manageable safety of tagraxofusp in blastic plasmacytoid dendritic cell neoplasm: a case series of pediatric and adolescent/young adult patients

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) predominantly occurs in adults ≥60 years old; 10-20% of cases are pediatric or adolescent/young adult (AYA) patients. Tagraxofusp (TAG, Elzonris®) is the only approved treatment for BPDCN; in the United States it is approved for patients aged ≥2 years. Data on treating pediatric and AYA BPDCN patients are limited. We present a case series of pediatric and AYA patients with BPDCN treated with TAG. Eight patients (five newly diagnosed; three relapsed/refractory [R/R]), aged 2-21 years, received 12 mcg/kg TAG. Seven patients were female; most had skin (n = 6) and/or bone marrow (n = 4) involvement. No new safety signals were identified. Grade 3 adverse events were headache (n = 1) and transaminitis (n = 2). Three patients with newly diagnosed BPDCN achieved complete response, one achieved partial response, and one had stable disease (SD). One patient with R/R BPDCN achieved a minor response; one had SD. Seven patients (88%) were bridged to stem cell transplant: 80% of newly diagnosed patients and 100% of R/R patients. Five patients remained alive at last follow-up. These cases highlight the efficacy and safety of TAG in pediatric and AYA patients for whom there is no other approved BPDCN therapy.

[Blastic plasmacytoid dendritic cell tumor treated with DVT regimen: a case report and literature review]

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressive hematological malignancy, there is no standard treatment and the prognosis is very poor. Affiliated Zhongshan Hospital of Dalian University report a case of 85-year-old BPDCN male patient treated with DVT regimen (decitabine combined with Venetoclax and thalidomide) and achieved complete remission. The patient with skin nodules and the pathology diagnosed BPDCN, the next generation sequencing of skin nodules showed mutations of IDH2 and ASXL1. DVT (decitabine combined with Venetoclax and thalidomide) has significant efficacy with rapid and deep remission for BPDCN, and the adverse effects is less, especially suitable for elderly patients who cannot tolerate intense chemotherapy.

A CD56- immunoblastoid variant of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive malignant hematologic neoplasm arising from plasmacytoid dendritic cells. It is a very rare tumor that constitutes less than 0.1% of all hematologic malignancies. Most patients with BPDCN present clinically with cutaneous lesions as the first sign of disease. Immunophenotypic variability with aberrant marker profiles has been reported. We report a case of a transcription factor 4 (TCF-4) + BPDCN, with negative CD56 expression in an 85-year-old woman with multiple skin nodules. A punch biopsy revealed a diffuse, monomorphous, and non-epidermotropic cell infiltrate involving the entire dermis. The infiltrate was composed of intermediate-sized cells with immunoblastoid morphology, which is an unusual morphologic variant. The neoplastic cells were strongly positive for CD45 and co-expressed CD4, CD123, TCF-4, BCL-2, and CD10. The Ki-67 proliferative rate was very high (90%). Negative immunostains included CD56, an unusual finding in BPDCN. This case illustrates the challenges encountered in the diagnosis of this entity, particularly in unusual morphologic variants and phenotypes. The elucidation of molecular signatures and development of targeted therapies for its management have been recently introduced and differ from acute myeloid leukemias. Hence, accurate diagnosis of BPDCN is critical for dermatopathologists.

Pediatric Blastic Plasmacytoid Dendritic Cell Neoplasm: A Case Report

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive neoplastic process of precursor plasmacytoid dendritic cells. The diagnostic evaluation of this heterogenous entity is challenging, requiring a comprehensive approach of incorporating clinical, morphologic, immunohistochemical, and molecular/cytogenetic evaluations. Optimal management of BPDCN remains controversial, and clinical outcomes continues to be poor. Pediatric cases of BPDCN are rare and to our knowledge, this is the second case of BPDCN described in a Hispanic child, first one was described outside the US in Peru. Here, we report a case of a juvenile patient of Hispanic origin presenting with cutaneous and bone marrow involvement and initially misdiagnosed as a cutaneous infection that resulted in subsequent delaying of necessary chemotherapy for 2 months. Biopsy of the lesion showed diffuse infiltration of immature cells involving the dermis with classical sparring of epidermis. A huge panel of immunohistochemical stains were performed to reach the diagnosis of BPDCN. Staging bone marrow biopsy also revealed involvement by BPDCN. Treatment was not only delayed in this patient but also due to the rarity of BPDCN in pediatric population, the subsequent therapeutic decisions were challenging for the primary oncology team as it was based solely on published literature on adult population. Our case report will not only add one more case in the pediatric age group, but also will also emphasize that although BPDCN has a grave prognosis in the elderly, timely diagnosis with prompt treatment is the key to complete remission in pediatric BPDCN population.

Multiple Genomic Alterations, Including a Novel AFF4::IRF1 Fusion Gene, in a Treatment-Refractory Blastic Plasmacytoid Dendritic-Cell Neoplasm: A Case Report and Literature Review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with an aggressive clinical course and poor prognosis. The genetic abnormalities in BPDCN are heterogeneous; therefore, its molecular pathogenesis and the prognostic importance of genomic alterations associated with the disease are not well defined. Here we report a case of BPDCN with a novel AFF4::IRF1 fusion predicted to lead to a loss-of-function of the IRF1 tumor suppressor, somatic mutations of ASXL1, TET2, and MYD88, as well as multiple intrachromosomal deletions. The patient showed resistance to Tagraxofusp and Venetoclax, and he died about 16 months after diagnosis. Considering the predicted effect of the AFF4::IRF1 fusion on IRF1's antitumor effects and immune regulation, and the possibility of its relevance to the aggressive course observed in this case, we propose further evaluation of the clinical significance of this fusion in BPDCN in future cooperative group studies and the consideration of therapeutic strategies aimed at restoring IRF1-dependent antineoplastic effects in such cases.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

Blastic plasmacytoid dendritic cell neoplasm: a comprehensive review in pediatrics, adolescents, and young adults (AYA) and an update of novel therapies

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that can involve the bone marrow, peripheral blood, skin, lymph nodes, and the central nervous system. Though more common in older adults, BPDCN has been reported across all age groups, including infants and children. The incidence of pediatric BPDCN is extremely low and little is known about the disease. Pediatric BPDCN is believed to be clinically less aggressive but often with more dissemination at presentation than adult cases. Unlike adults who almost always proceed to a hematopoietic stem cell transplantation in first complete remission if transplant-eligible, the majority of children can be cured with a high-risk acute lymphoblastic leukemia-like regimen. Hematopoietic stem cell transplantation is recommended for children with high-risk disease, the definition of which continues to evolve, or those in relapse and refractory settings where outcomes continue to be dismal. Novel agents used in other hematologic malignancies and CD123 targeted agents, including chimeric antigen receptor T-cells and monoclonal/bispecific antibodies, are being brought into research and practice. Our goal is to provide a comprehensive review of presentation, diagnosis, and treatment by review of pediatric cases reported for the last 20 years, and a review of novel targeted therapies and therapies under investigation for adult and pediatric patients.

Venetoclax monotherapy as front-line therapy for blastic plasmacytoid dendritic cell neoplasm

Venetoclax is an approved treatment for relapsed/refractory Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN). We report a unique case of venetoclax monotherapy used for front-line induction and as a bridge to allogeneic hematopoietic stem cell transplantation (HCT). Venetoclax therapy resulted in rapid complete resolution of skin lesions, however, treatment interruption due to neutropenia led to brisk cancer recurrence. Fortunately, the patient responded to re-challenge and was able to undergo HCT. Venetoclax is active in the first-line treatment setting for BPDCN, however its effect on blood counts and durability of response should be further studied.

Blastic plasmacytoid dendritic cell neoplasm in an adolescent female: a rare entity with challenging diagnosis and management

Blastic plasmacytoid dendritic cell neoplasm is a rare and aggressive haematopoietic neoplasm with poor prognosis. It usually presents with cutaneous lesions and symptoms secondary to bone marrow involvement. Due to rarity and lack of standard treatment protocols, these cases are difficult to diagnose and treat. We report a case of a female in early adolescence who presented with skin nodules on the leg. The diagnosis was established by immunophenotypic studies. We discuss the investigations and treatment options available to diagnose and treat this malignancy.

Plasmacytoid dendritic cell neoplasms

Plasmacytoid dendritic cells (pDCs) are type I interferon-producing cells that modulate immune responses. There are two types of pDC neoplasms: 1) mature pDC proliferation (MPDCP) associated with myeloid neoplasm and 2) blastic pDC neoplasm (BPDCN). MPDCP is a clonal expansion of mature pDCs that is predominantly associated with chronic myelomonocytic leukemia. In contrast, BPDCN is a clinically aggressive myeloid malignancy involving the skin, bone marrow, lymphatic organs, and central nervous system. There are various types of skin lesions, ranging from solitary brown or violaceous to disseminated cutaneous lesions, which often spread throughout the body. The expression of CD4, CD56, CD123, and pDC markers (TCL-1, TCF4, CD303, and CD304, etc.) are typical immunophenotype of BPDCN. Historically, BPDCN treatment has been based on acute leukemia regimens and allogeneic hematopoietic cell transplantation in selected patients. Recent advances in molecular biology and genetics have led to the development of targeted agents, such as tagraxofusp (a recombinant fusion protein targeting CD123), anti-CD123 CAR-T cells, XmAb14045, and IMGN632. Lastly, this review provides a comprehensive overview of pDC neoplasms.

Diagnosis, treatment, and genetic characteristics of blastic plasmacytoid dendritic cell neoplasm: A review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a highly aggressive and extremely rare hematologic disease with a poor prognosis, involving mainly the skin and bone marrow. The immunophenotype of these tumor cells is characterized by the expression of CD4, CD56, CD123, TCL-1, and CD303. To date, no consensus has been reached on the standard of care for BPDCN. Currently, clinical treatment is mainly based on high-dose chemotherapy combined with hematopoietic stem cell transplantation. However, this treatment method has limitations for elderly, frail, and relapsed/refractory patients. In recent years, breakthroughs in molecular biology and genetics have not only provided new ideas for the diagnosis of BPDCN but also helped develop targeted treatment strategies for this disease. The emergence of targeted drugs has filled the gap left by traditional therapies and shown great clinical promise. This article focuses on the latest advances in genetics and targeted therapies for BPDCN, especially the emerging therapies that may provide new ideas for the clinical treatment of BPDCN.

North American Blastic Plasmacytoid Dendritic Cell Neoplasm Consortium: position on standards of care and areas of need

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with historically poor outcomes and no worldwide consensus treatment approach. Unique among most hematologic malignancies for its frequent cutaneous involvement, BPDCN can also invade other extramedullary compartments, including the central nervous system. Generally affecting older adults, many patients are unfit to receive intensive chemotherapy, and although hematopoietic stem cell transplantation is preferred for younger, fit individuals, not all are eligible. One recent therapeutic breakthrough is that all BPDCNs express CD123 (IL3Rα) and that this accessible surface marker can be pharmacologically targeted. The first-in-class agent for BPDCN, tagraxofusp, which targets CD123, was approved in December 2018 in the United States for patients with BPDCN aged ≥2 years. Despite favorable response rates in the frontline setting, many patients still relapse in the setting of monotherapy, and outcomes in patients with relapsed/refractory BPDCN remain dismal. Therefore, novel approaches targeting both CD123 and other targets are actively being investigated. To begin to formally address the state of the field, we formed a new collaborative initiative, the North American BPDCN Consortium (NABC). This group of experts, which includes a multidisciplinary panel of hematologists/oncologists, hematopoietic stem cell transplant physicians, pathologists, dermatologists, and pediatric oncologists, was tasked with defining the current standard of care in the field and identifying the most important research questions and future directions in BPDCN. The position findings of the NABC's inaugural meetings are presented herein.

Blastic plasmacytoid dendritic cell neoplasm: A clinicopathological diagnostic dilemma report of three cases with review of literature

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a highly aggressive hematologic neoplasm and classified under acute myeloid leukemia. Here, we describe the clinicopathological features of three cases of BPDCN: two with classical and one uncommon immunophenotype. A-35-year-old female (case 1) presented with complaint of nasal mass and generalized lymphadenopathy. Biopsy from axillary lymph node showed infiltration by cells with scant cytoplasm which were immunopositive for LCA, CD4, CD43, and ALK1. Flowcytometry showed positivity for CD45, CD4, CD33, and CD123 while negative for rest all markers. The other two cases have classical immunophenotype. In clinical practice, nasal mass with lymphadenopathy suggests natural killer T-cell/peripheral T-cell lymphoma. Again immunohistochemical positivity for CD4, CD43, and ALK while negativity for CD3 suggests anaplastic large cell lymphoma. In this case, morphology and extensive bone marrow involvement raise the suspicion. Fowcytometry positivity for HLADR, CD123, and CD33 helps in making diagnosis.

Patients with blastic plasmacytoid dendritic cell neoplasm in pregnancy: A rare case report

RATIONALE

Previous clinical reports of patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) in pregnancy are rare.

PATIENT CONCERNS

The present study presents the case of 37-year-old women exhibiting third trimester with progressive painless, abdominal skin nodules.

INTERVENTIONS AND OUTCOMES

A 37-year-old pregnant woman with BPDCN and partial placenta previa and racket-shaped placenta. After comprehensive evaluation, the pregnancy status ends at 37 weeks and 6 days by cesarean section of lower uterus and no abnormality in the newborn.

LESSONS

Pregnant women diagnosed with BPDCN in the third trimester should terminate the pregnancy promptly for further treatment.

Conventional Therapeutics in BPDCN Patients-Do They Still Have a Place in the Era of Targeted Therapies?

No benchmark treatment exists for blastic plasmacytoid dendritic cell neoplasm (BPDCN). Since the malignancy is chemo-sensitive, chemotherapy followed by hematopoietic stem cell transplantation remains an effective treatment. However, relapses frequently occur with the development of resistance. New options arising with the development of therapies targeting signaling pathways and epigenetic dysregulation have shown promising results. In this review, we focus on conventional therapies used to treat BPDCN and the novel therapeutic approaches that guide us toward the future management of BPDCN.

Clinical Insights into the Management of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is aggressive hematologic malignancy derived from plasmacytoid dendritic cell precursors of myeloid cell lineage. Patients frequently present with bruise-like skin lesions, which typically are followed months later by progressive cytopenias. Historically, BPDCN prognosis has been dismal, with median overall survival ranging from 9 to 13 months. In the past 2 decades, our understanding of BPDCN pathogenesis has led to the successful development of novel therapeutics. In December 2018, the FDA approved tagraxofusp-erzs for adults and pediatric patients older than 2 years who have either treatment-naïve or relapsed/refractory BPDCN. Acute lymphoblastic leukemia (ALL)-based chemotherapy regimens also provide comparable outcomes to tagraxofusp. In our practice, for patients with good performance status, we use tagraxofusp, ALL-based chemotherapy regimens, or clinical trials as frontline induction therapy, followed by consolidation with allogeneic stem cell transplant once the first complete response has been achieved. Our induction regimen also includes intrathecal chemotherapy for central nervous system prophylaxis. Patients with poor performance status who are treatment-naïve or patients with relapsed/refractory disease have limited therapeutic options, and we strongly recommend enrollment in clinical trials; several novel agents and combinations are currently under clinical investigation for both treatment-naïve and relapsed/refractory BPDCN.

Targeting CD123 in blastic plasmacytoid dendritic cell neoplasm using allogeneic anti-CD123 CAR T cells

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with poor outcomes with conventional therapy. Nearly 100% of BPDCNs overexpress interleukin 3 receptor subunit alpha (CD123). Given that CD123 is differentially expressed on the surface of BPDCN cells, it has emerged as an attractive therapeutic target. UCART123 is an investigational product consisting of allogeneic T cells expressing an anti-CD123 chimeric antigen receptor (CAR), edited with TALEN^® nucleases. In this study, we examine the antitumor activity of UCART123 in preclinical models of BPDCN. We report that UCART123 have selective antitumor activity against CD123-positive primary BPDCN samples (while sparing normal hematopoietic progenitor cells) in the in vitro cytotoxicity and T cell degranulation assays; supported by the increased secretion of IFNγ by UCART123 cells when cultured in the presence of BPDCN cells. UCART123 eradicate BPDCN and result in long-term disease-free survival in a subset of primary patient-derived BPDCN xenograft mouse models. One potential challenge of CD123 targeting therapies is the loss of CD123 antigen through diverse genetic mechanisms, an event observed in one of three BPDCN PDX studied. In summary, these results provide a preclinical proof-of-principle that allogeneic UCART123 cells have potent anti-BPDCN activity.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressive hematologic malignancy derived from the precursors of plasmacytoid dendritic cells. Here the authors characterize the anti-tumor activity of allogeneic anti-CD123 CAR-T cells in preclinical models of BPDCN.

Blastic Plasmacytoid Dendritic Cell Neoplasm With Central Nervous System Involvement: A Case Report

Blastic plasmacytoid dendritic cell neoplasm is a rare hematologic neoplasm characterized by cutaneous, hematologic, and central nervous system (CNS) involvement with poor prognosis. Diagnosis is made by flow cytometry, although there are no specific markers, making its diagnosis challenging. So far, with the available evidence, acute lymphoid leukemia-type schemes and consolidation with allogeneic transplant seem to become the first-line therapy. With its characterization, new therapies directed toward CD123 and the anti-apoptotic protein Bcl-2 have appeared to prolong the survival of these patients. We present a case of a 27-year-old male patient diagnosed with blastic plasmacytoid dendritic cell neoplasm with unusual CNS manifestations and without skin involvement who achieved complete remission with venetoclax and improvement of neurological symptoms, making him a candidate for hematopoietic stem cell transplant.

Allogeneic hematopoietic cell transplantation for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN)

Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) is an aggressive hematological malignancy; however, some patients achieve durable remission with allogeneic hematopoietic cell transplantation (allo-HCT). We report on all 17 patients with BPDCN who underwent allo-HCT at our center between 2000 and 2020. The median age was 39 (18-67) years. All (n = 16, 94%), except one patient, had systemic disease involving bone marrow and/or other organs. Ten patients (59%) were in first complete remission (CR1) at allo-HCT. The donor source was matched related or unrelated in ten (59%) and alternate donor in seven (41%) patients. Five (31%) patients developed acute graft-versus-host disease (GVHD), all grade I-II. The cumulative incidence (CI) of chronic GVHD at five-year was 34%. The CI of non-relapse mortality at one-year was 29%. Progression-free survival (PFS) rates at two-year and five-year were 49% (95% CI = 22-71%) and 39% (95% CI = 14-64%), respectively. The two-year and five-year overall survival (OS) rates were 65% (95% CI = 38-82%) and 40% (95% CI = 12-68%), respectively. The five-year rate for both PFS and OS was 80% in CR1 patients versus 0% in patients not in CR1. In conclusion, allo-HCT provides long-lasting remissions in BPDCN patients, particularly when performed in CR1.

A very rare case of FLT3-D835 positive blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasms (BPDCNs) are extremely rare and aggressive hematological malignancies that derive from precursors of plasmacytoid dendritic cells (pDC) and frequently involve skin lesions and bone marrow infiltration. They mostly affect the elderly population and the prognosis is poor with the therapeutic choices currently available. Diagnosis is made with the help of tools such as immunohistochemistry and flow cytometry. Here, we present a particular case of BPDCN with a positive FLT3-D835 mutation and we discuss the possible impact this may have on the evolution of the disease and response to treatment.

Targeting CD123 in BPDCN: an emerging field

INTRODUCTION

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy with historically poor outcomes for patients, often refractory to traditional chemotherapy. Recent research has focused on targeted therapy to improve responses and limit potential toxicity.

AREAS COVERED

CD123 (also known as IL-3 Rα) is a cell surface marker and attractive therapeutic target for many myeloid malignancies, particularly BPDCN, whose cells ubiquitously overexpress CD123. We review the history of CD123 research regarding BPDCN, recent advances including FDA approval of tagraxofusp (formerly SL-401) for BPDCN, and ongoing clinical studies utilizing novel therapeutic strategies to target CD123.

EXPERT OPINION

The approval of tagraxofusp for the treatment of BPDCN in December 2018 drastically changed the treatment landscape for patients with this rare neoplasm. While tagraxofusp is better tolerated than traditional multi-agent chemotherapy regimens, it requires close monitoring and sound clinical judgment by providers to prevent and mitigate severe treatment-related complications with special attention to the recognition and management of capillary leak syndrome (CLS). Several other promising strategies for targeting CD123 in BPDCN are currently under investigation, including antibody-drug conjugates, T-cell engagers, and CAR-T cellular therapeutics. These CD123 targeted approaches may soon become standard of care for patients with this difficult to treat malignancy.

Blastic Plasmacytoid Dendritic Cell Neoplasm without Cutaneous Manifestation: A Case Report

Patient: Male, 85-year-old

Final Diagnosis: Blastic plasmacytoid dendritic cell neoplasm

Symptoms: Dizziness • leg pain • malaise • weakness

Medication: —

Clinical Procedure: Bone marrow biopsy • lumbar puncture

Specialty: Hematology • Oncology

A case report of blastic plasmacytoid dendritic cell neoplasm in a hispanic child

Plasmacytoid dendritic cell neoplasms are aggressive and rare hematologic malignancies characterized by clonal expansion of plasmacytoid dendritic cells with frequent cutaneous involvement. The pathogenesis is not well established, and it shows enhanced expression of CD56, CD4 and CD123 detected by flow cytometry and immunohistochemistry. We report a case report of this rare disease in a hispanic child with complete remission after using a protocol for high-risk acute lymphoblastic leukemia.

Tagraxofusp Treatment: Implications for Patients With Blastic Plasmacytoid Dendritic Cell Neoplasm

BACKGROUND

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, clinically aggressive, and often fatal hematologic malignancy. BPDCN is not a new entity, but it has been renamed and reclassified, which, in part, contributes to it being underrecognized. In 2018, tagraxofusp became the first U.S. Food and Drug Administration-approved therapy for BPDCN.

OBJECTIVES

This article aims to educate oncology nurses about tagraxofusp's dosing regimen, side effects, and how to manage patients undergoing treatment in inpatient and outpatient settings.

METHODS

The authors reviewed content related to the safety and clinical management of tagraxofusp, as well as content that supports patient and provider education.

FINDINGS

Capillary leak syndrome (CLS) is the most serious adverse event reported with tagraxofusp; therefore, nurses should stop tagraxofusp administration until all CLS-related symptoms have resolved. Hypersensitivity reactions and hepatotoxicity have also been observed in patients treated with tagraxofusp and should be monitored during treatment cycles.

Pediatric blastic plasmacytoid dendritic cell neoplasm: report of four cases and review of literature

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy with poor outcome. Four children with BPDCN treated at our hospital were enrolled. All the four cases presented with cutaneous lesions. Bone marrow and central nervous system was involved in 50% and 25% of patients, respectively. The whole exome sequencing analysis revealed that KMT2 family genes were the most frequently mutated (4/4, 100%), followed by IKZF2 (2/4, 50%). The point mutation p.D348N was found in three patients and one patient had p.C394Y mutation in the KMT2C gene. Translocation of KMT2A-MLLT3 was found in Case 2. Case 1 had complex karyotype, who was induced by acute myeloid leukemia-like regimens. Although he received allogeneic hematopoietic stem cell transplantation twice as well as CD123 chimeric antigen receptor T cell therapy, the disease still progressed and he died 37 months after diagnosis. The other three patients were treated with Interfant-99 protocol. They tolerated the therapy well without significant toxicities and now in complete remission so far with a median follow up time of 9 months. More studies are needed to address the question whether the complex karyotype and KMT2 family genes are the causes of the relapse and refractory in BPDCN.

Myeloid sarcoma, chloroma, or extramedullary acute myeloid leukemia tumor: A tale of misnomers, controversy and the unresolved

The World Health Organization classification and definition of "myeloid sarcoma" is imprecise and misleading. A more accurate term is "extramedullary acute myeloid leukemia tumor (eAML)." The pathogenesis of eAML has been associated with aberrancy of cellular adhesion molecules, chemokine receptors/ligands and RAS-MAPK/ERK signaling. eAML can present with or without synchronous or metachronous intramedullary acute myeloid leukemia (AML) so a bone marrow evaluation is always recommended. Accurate diagnosis of eAML requires tissue biopsy. eAML confined to one or a few sites is frequently treated with local therapy such as radiotherapy. About 75-90% of patients with isolated eAML will develop metachronous intramedullary AML with a median latency period ranging from 4 to 12 months; thus, patients with isolated eAML may also be treated with systemic anti-leukemia therapy. eAML does not appear to have an independent prognostic impact; selection of post-remission therapy including allogeneic hematopoietic cell transplant (alloHCT) is typically guided by intramedullary disease risk. Management of isolated eAML should be individualized based on patient characteristics as well as eAML location and cytogenetic/molecular features. The role of PET/CT in eAML is also currently being elucidated. Improving outcomes of patients with eAML requires further knowledge of its etiology and mechanism(s) as well as therapeutic approaches beyond conventional chemotherapy, ideally in the context of controlled trials.

Blastic plasmacytoid dendritic cell neoplasms: results of an international survey on 398 adult patients

The purpose of this study is to describe the clinical and prognostic features and to evaluate the outcome of different therapeutic approaches among patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) who have been diagnosed and treated in different institutions. A total of 398 patients from 75 centers were included in the study. Treatment consisted of non-Hodgkin lymphoma (NHL)-like regimens in 129 (32.8%) patients and acute leukemia (AL)-like regimens in 113 (23.5%) patients. In 61 (15.5%) and 16 (4.1%) patients, chemotherapy was followed by allogeneic and autologous hematopoietic stem cell transplantation (HSCT), respectively. Twenty-seven (6.9%) patients received radiotherapy, 6 (1.5%) received new agents, and 62 (15.7%) received palliative care. After a median follow-up of 12 months, median overall survival (OS) was 18 months. Patients who received NHL/AL-like regimens, followed by allogeneic HSCT, had the best outcome; median OS was not reached. OS was 65 months for patients who underwent autologous HSCT; 18 months and 14 months, respectively, for those treated with AL-like and NHL-like regimens without consolidation; and 4 months for those receiving palliative care (P < .001). In BPDCN, chemotherapy with lymphoma- or AL-like regimens, followed by transplantation, represents the therapeutic strategy associated with the best outcome. Consolidation with allogeneic HSCT, when feasible, appears superior to autologous HSCT.

Tagraxofusp and anti-CD123 in blastic plasmacytoid dendritic cell neoplasm: a new hope

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy, characterized by poor prognosis if treated with conventional therapy. Allogenic hematologic stem cell transplant can improve survival and can be curative, but it is available in a small percentage of patients given that the median age at diagnosis is 70 years. In this scenario it is assumed that only the development of precision medicine-driven therapy will change BPDCN patient prognosis. CD123 (the α-subunit of interleukin (IL)-3 receptor) is over-expressed on BPDCN cells surface and seems to be the ideal marker to develop antibody-based therapies. Tagraxofusp (Elzonris^®), a recombinant immunotoxin consisting of human interleukin-3 fused to a truncated diphtheria toxin, has been approved by FDA in December 2018 for the treatment of BPDCN in adult and pediatric patients. tagraxofusp has shown promising clinical activity, with a high overall response rate and quite manageable safety profile even in elderly patients. It seems to improve overall survival too, but comparative trials are necessary to confirm this. Adverse events are commonly reported and the most important are transaminitis, thrombocytopenia and capillary leak syndrome (CLS). Therefore, to prevent the onset of severe CLS is recommended to reserve tagraxofusp for patients with preserved hepatic and cardiac functions, and to strictly observe serum albumin level. Further studies are required to resolve many several unanswered questions about tagraxofusp. In this review, we will resume and discuss pharmacological characteristic of tagraxofusp, results of clinical trials leading to its approval by FDA in 2018 and future perspectives about its use in BPDCN and other hematological malignancies.