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

Ulcerating skin lesions from blastic plasmacytoid dendritic cell neoplasm responding to low-dose radiotherapy-a case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that can manifest with skin nodules and erythematous plaques. In most cases BPDCN progresses rapidly, causing multiple skin lesions and also affecting internal organs and bone marrow, warranting initiation of systemic therapies or hematopoietic stem cell transplantation (HCT). Although not curative, radiotherapy for isolated lesions might be indicated in case of (imminent) ulceration and large or symptomatic lesions. To this end, doses of 27.0-51.0 Gy have been reported. Here, we present the case of an 80-year-old male with BPDCN with multiple large, nodular, and ulcerating lesions of the thorax, abdomen, and face. Low-dose radiotherapy of 2 × 4.0 Gy was administered to several lesions, which resolved completely within 1 week with only light residual hyperpigmentation of the skin in affected areas and reliably prevented further ulceration. Radiotoxicity was not reported. Therefore, low-dose radiotherapy can be an effective and low-key treatment in selected cases of BPDCN, especially in a palliative setting, with a favorable toxicity profile.

Low-dose venetoclax combined with azacitidine for blastic plasmacytoid dendritic cell neoplasm: a case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that is highly aggressive with a poor prognosis. There is no standard treatment for BPDCN. Although conventional chemotherapies are usually sensitive in the initial therapy, relapse and drug resistance are inevitable within a short duration. Targeted therapies have enlightened new prospects for the treatment of BPDCN, especially for those in a frail state and intolerable to standard chemotherapies or hematopoietic stem cell transplantation. Here, we report an 82-year-old man diagnosed with cutaneous-limited BPDCN. Considering the old age and limited involvement of the tumor, we reduced the dosage of venetoclax. His skin lesions subsided significantly after 1 cycle of azacytidine (100 mg d1-7) combined with reduced doses of venetoclax (200 mg d1-14). The reduction in the dose of venetoclax avoided severe myelosuppression while achieving satisfactory outcomes. The patient received 2 cycles of therapy with no skin lesions re-occurred for 7 months before relapsing.

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.

Blastic Plasmacytoid Dendritic Cell Neoplasm: A Comprehensive Review of the Disease, Central Nervous System Presentations, and Treatment Strategies

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematologic malignancy with poor outcomes. The World Health Organization (WHO) redefined BDCN as a distinct disease entity in 2016. BPDCN arises from plasmacytoid dendritic cells, manifesting primarily in the skin, bone marrow, and lymph nodes, occasionally involving the central nervous system (CNS). This presents challenges in diagnosis and treatment, with CNS involvement often overlooked in standard diagnostic workups due to BPDCN's rarity and patients often being neurologically asymptomatic at diagnosis. CNS involvement typically emerges during relapse, yet clinical trials often exclude such cases, limiting our understanding of its development and treatment. Treatment options for CNS involvement include intrathecal (IT) chemotherapies like methotrexate and cytarabine, often in combination with systemic agents. Tagraxofusp and traditional regimens for acute myeloid leukemia show limited success at preventing CNS relapse, prompting exploration of combined therapies like hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (HyperCVAD) with venetoclax and adding IT chemotherapy to other backbones. Ongoing clinical trials investigating emerging therapies offer hope despite limited focus on CNS implications. Trials incorporating CNS-involved patients aim to pioneer novel treatment approaches, potentially reshaping BPDCN management. Understanding CNS involvement's complexities in BPDCN remains crucial for tailored treatments and better patient outcomes.

Primary blastic plasmacytoid dendritic cell neoplasm: a US population-based study

Background

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and poorly understood hematopoietic malignancy. This study aimed to investigate the clinical characteristics and prognostic factors in patients with primary BPDCN.

Methods

Patients diagnosed with primary BPDCN from 2001 to 2019 were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Survival outcome was analysed with Kaplan-Meier method. Prognostic factors were evaluated based on the univariate and multivariate accelerated failure time (AFT) regression analysis.

Results

A total of 340 primary BPDCN patients were included in this study. The average age was 53.7 ± 19.4 years, with 71.5% being male. The mostly affected sites were lymph nodes (31.8%). Most patients (82.1%) received chemotherapy, while 14.7% received radiation therapy. For all the patients, the 1-year, 3-year, 5-year, and 10-year overall survival (OS) were 68.7%, 49.8%, 43.9%, and 39.2%, respectively, and the corresponding disease-specific survival (DSS) were 73.6%, 56.0%, 50.2%, and 48.1%, respectively. Univariate AFT analysis showed that older age, marital status of divorced, widowed and separated at diagnosis, primary BPDCN only, treatment delay for 3-6 months and without radiation therapy were significantly associated with poor prognosis of primary BPDCN patients. But multivariate AFT analysis indicated that older age was independently associated with worse survival, while second primary malignancies (SPMs) and radiation therapy were independently associated with extended survival.

Conclusions

Primary BPDCN is a rare disease with poor prognosis. Advanced age was linked independently to poorer survival, while SPMs and radiation therapy were linked independently to prolonged survival.

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.