Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) Is Highly BCL-2 Dependent and Sensitive to Venetoclax

Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a particularly aggressive hematologic malignancy with median survival of <12 months and no standard therapy. BPDCN involves the skin in nearly all patients, and frequently infiltrates bone marrow and lymph nodes. Its normal counterpart may be the plasmacytoid dendritic cell (pDC), leading to the name BPDCN. Outcomes are poor with cytotoxic chemotherapy. An interleukin 3-diphtheria toxin fusion (SL-401) has activity in BPDCN (Frankel, Blood 2014), but additional novel agents are urgently needed. BPDCN over-expresses the anti-apoptotic protein BCL-2 compared to normal pDCs (Sapienza, Leukemia 2014). We confirmed this by RNA-sequencing 12 BPDCNs and pDCs from 4 normal donors (reads/kb mapped [RPKM] 22.7 vs 1.33, P=0.0005). BPDCN shares some genetic characteristics with myeloid malignancies, and some acute myeloid leukemias (AMLs) are dependent on BCL-2. We performed RNA-seq on 6 BPDCN and 16 AML patient-derived xenografts (PDXs) and found higher BCL-2 expression in BPDCN (RPKM 48.2 vs 11.5, P=0.0005). We analyzed BCL-2 expression by immunohistochemistry in patient skin and bone marrow biopsies and found that all BPDCNs had BCL-2 staining that was equivalent to or stronger than that of any AMLs. We next tested BPDCN cell lines, primary patient samples, and patient-derived xenografts (PDXs) for BCL-2 dependence and sensitivity to the BCL-2 inhibitor venetoclax (previously ABT-199). Using BH3 profiling, we found that BPDCN is markedly dependent on BCL-2 to prevent mitochondrial cytochrome c release in response to apoptotic stimuli. In comparison to AML, BPDCN had significantly more cytochrome c release after BAD peptide stimulation (81.1% vs 11.8%, P<0.0001), suggesting greater dependency on BCL-2 and/or BCL-XL. BPDCN was uniformly sensitive to treatment with venetoclax in vitro, in cell lines and primary cells, as measured by direct cytotoxicity and Annexin V apoptosis assays. We used dynamic BH3 profiling (Montero, Cell 2015) in primary BPDCNs and PDXs (n=7) to measure early apoptotic signals after 4-hr exposure to venetoclax, avoiding the need for prolonged culture. BPDCNs were more likely than AMLs to undergo cytochrome c release in response to BIM peptide stimulation after 4 hours of venetoclax (increase in apoptotic potential, or "delta priming" 63.4% vs 14.5%, P<0.0001). Targeted sequencing of the BPDCNs found various combinations of mutations in TP53, FLT3, JAK2, SRSF2, TET2, ASXL1, IDH2, GNB1, NRAS and/or ZRSR2. All responded equally to venetoclax, suggesting the response was independent of genotype. Next we treated two BPDCN PDXs in vivo in NSG mice with oral venetoclax (100 mg/kg/day x 28 days). PDX genetics were, PDX1: ASXL1 G646fs*, NRAS G13D, JAK2 V617F, TET2 D1017fs*, and TET2 Q1687fs*; PDX2: IDH2 R140Q, TP53 S241F, TP53 C176Y, and ZRSR2 S188*. Venetoclax caused significant reductions in BPDCN burden in peripheral blood, spleen, and bone marrow after 21 days of therapy in both models. Overall survival was improved in venetoclax compared to vehicle treated animals in a leukemia-watch cohort (57 vs 36 days, P=0.0025). On the basis of these findings, we treated a relapsed BPDCN patient with venetoclax. He is an 80 year-old male who had received 3 prior lines of therapy. He had extensive skin disease with multiple cutaneous tumors, lymph node involvement, and >80% bone marrow blasts. His BPDCN carried the mutations ASXL1 Y581fs*, ASXL1 E553fs*, GNB1 K57E, IDH2 R140W, and NRAS G12D, and expressed high levels of BCL-2 protein in bone marrow and skin. BH3 profiling of a skin tumor biopsy revealed marked BCL-2 dependence and dynamic BH3 response to venetoclax (4 hr delta priming 55.6%). We treated him using a regimen recently FDA-approved for chronic lymphocytic leukemia (CLL) consisting of weekly dose escalation (20 -> 50 -> 100 -> 200 mg), to a target dose of 400 mg daily. At the time of this writing, he had reached 200 mg without significant toxicity, including no evidence of tumor lysis syndrome. His skin disease has responded remarkably (Figure), with the first response evident within 10 days. Our data suggests that BPDCN is highly sensitive to BCL-2 inhibition, which could provide an urgently needed new treatment for patients with this disease. We propose that BCL-2 inhibition should undergo expedited clinical evaluation in BPDCN. In addition, this case offers an example of precision cancer medicine by functional rather than genetic means. Figure Figure. Disclosures Davids: Infinity: Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Gilead: Honoraria; Janssen: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria, Research Funding; TG Therapeutics: Honoraria, Research Funding; Abbvie: Consultancy, Honoraria. Stone:ONO: Consultancy; Novartis: Consultancy; Amgen: Consultancy; Seattle Genetics: Consultancy; Roche: Consultancy; Celator: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy; Jansen: Consultancy; Pfizer: Consultancy; Juno Therapeutics: Consultancy; Merck: Consultancy; Sunesis Pharmaceuticals: Consultancy; Xenetic Biosciences: Consultancy. Konopleva:Reata Pharmaceuticals: Equity Ownership; Abbvie: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Stemline: Consultancy, Research Funding; Eli Lilly: Research Funding; Cellectis: Research Funding; Calithera: Research Funding. Letai:AbbVie: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Research Funding; Tetralogic: Consultancy, Research Funding. Lane:N-of-1: Consultancy; Stemline Therapeutics: Research Funding.

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Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN): A Large Single-Center Experience: Analysis of Clinical and Molecular Characteristics and Patient Outcomes

Blood ◽

10.1182/blood.v126.23.3746.3746 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3746-3746 ◽

Cited By ~ 5

Author(s):

Naveen Pemmaraju ◽

Hagop M. Kantarjian ◽

Jorge E. Cortes ◽

Madeleine Duvic ◽

Joseph D Khoury ◽

...

Keyword(s):

Clinical Trial ◽

Clinical Trials ◽

Dendritic Cell ◽

Board Of Directors ◽

Research Funding ◽

Plasmacytoid Dendritic Cell ◽

Cell Transplant ◽

Advisory Committees ◽

Significant Difference ◽

Cell Neoplasm

Abstract Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive hematologic malignancy with heterogeneous clinical presentation and no available standard therapy. Little is known about the clinical characteristics, molecular characterization, and outcomes of patients (pts) with BPDCN. Methods: We conducted a retrospective review of pts age ≥18 years with a confirmed pathological diagnosis of BPDCN. Results: 37 pts evaluated at our institution between October 1998-June 2015 were identified. Table 1 shows baseline pt characteristics. Bone marrow (BM) was involved in 23 (62%), skin in 26(70%), lymph nodes in 11(30%), central spinal fluid (CSF) in 3 (8%) and 1 (3%) pt each had disease involving brain, uterus/ovary, elbow/soft tissue, and pleural fluid. Tumor immunophenotype demonstrated: CD4+ (31/32), CD56+ (29/32), TCL-1+ (19/21), CD 123+ (22/23). Additionally, CD22 was expressed in 3/9 pts. Frontline therapies received: 19 (51%) HCVAD; 5 (14%) CHOP, 5 (14%) clinical trials, 2 (5%) bortezomib-based, 1 AML induction with daunorubicin+ARAC, 1 oral MTX, 1 IFN-based therapy, 3 other regimens. 5 (14%) pts received radiation (XRT) as part of their therapy. Median follow-up time was 7 months [1-27 mo]. Median number of chemotherapy regimens was 1 [1-6]. Complete remission (CR1) (by standard AML criteria) was achieved in 19 pts (51%) with a median CR1 duration of 19 mo [1-39 mo]. Median overall survival (OS) was 23 mo [6-45 mo]. 23 (69%) pts died, the most common cause of death being multi-organ failure. Among 14 (38%) pts without BM involvement at diagnosis, all 14 had skin involvement. Comparison of pts with BM involvement versus skin-only showed no difference in outcomes. For pts with BM disease, median OS and median CR1 were 23 mo [1-45 mo] and 21 mo [1-39 mo], respectively. For pts with skin-only disease,median OS and median CR1 were 18 mo [1-31 mo] and 19 mo [1-23 mo], respectively, p =0.43 (OS), p=0.78 (CR1). 10 pts (27%) received stem cell transplant (SCT) [7 allogeneic (including 3 cord blood) and 3 autologous). The median OS for pts receiving SCT (n=10) was 18 mo [8-40 mo] versus 23 mo [1-45] for non-SCT group (n=27), p = 0.98. 19 pts (51%) received HCVAD as part of first-line therapy: median OS was 18 mo [1-45 mo] and median CR1: 21 mo [1-39 mo]. Out of 16 pts evaluable for response, 15 achieved CR1; 1 pt died at day 15 (pneumonia). A clinically validated 28-gene molecular panel (next-generation sequencing for commonly mutated genes in myeloid malignancies) is now being performed prospectively on all new pts with BPDCN seen at our institution (thus far, n=9); notably, all 9 have expressed some form of TET2 mutation [ordered mutations=3(c.1648C>T p.R550; c.3781C>T p.R1261C; c.4365del p.M1456fs*2)], ordered+variant=2,variants=4], confirming our earlier finding of occurrence of TET2 mutations in pts with BPDCN (Alayed K, et al Am J Hematol 2013). Thus far, there has been no statistically significant difference in terms of response rates in pts with known TET2 mutations/variants (n=9) vs all others/not done (n=26). Conclusions: Among patients with BPDCN, we observed an older, male predominance, a high incidence of TET2 mutations and, despite intensive chemotherapy and achievement of CR1 in many pts, most still experience relapse and short survival. Therefore, there is an urgent need for novel therapies. Therapies targeting cell surface CD123 and CD56, are available in 2 separate clinical trials at our institution: SL-401 (DT-IL3), which demonstrated 7/9 (78%) major responses including 5 CR, after a single cycle of therapy, (Frankel et al, Blood 2014) is currently being tested in an ongoing multicenter phase I/II trial (Stemline Therapeutics Inc, ClinicalTrials.gov Identifier: NCT02113982, refer to separate abstract ASH 2015) and Lorvotuzumab Mertansine (ImmunoGen, Inc), an antibody-drug conjugate targeting CD56 (ClinicalTrials.gov Identifier: NCT02420873), is in an ongoing ph II trial in CD56-expressing hematologic malignancies, including BPDCN. Table 1. Baseline characteristics (N = 37) Characteristic N (%) / [range] Median age, years 62[20 - 86] Male 33 (89) Median WBC x 109/L 5.9 [1.7-76.5] Median Hemoglobin g/dL 12.9 [6.8-17.1] Median Platelet x 109/L 130 [22-294] Median BM blast 13[0-95] Cytogenetics (n=27)DiploidComplexDeletion 12p13 17 8 1 Miscellaneous 1 28-gene profile (n=9); includes mutations& variantsTET2ASXL1MPLTP53IDH1IDH2 9 3 2 1 1 1 Disclosures Pemmaraju: Stemline: Research Funding; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; LFB: Consultancy, Honoraria. Off Label Use: No standard of care available. clinical trial drug therapies/investigation/trial only various cytotoxic chemotherapies used in ALL, AML, other blood cancers. Cortes:BMS: Consultancy, Research Funding; BerGenBio AS: Research Funding; Teva: Research Funding; Pfizer: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Ambit: Consultancy, Research Funding; Arog: Research Funding; Celator: Research Funding; Jenssen: Consultancy. Duvic:Innate Pharma: Research Funding; Tetralogics SHAPE: Research Funding; Cell Medica Ltd: Consultancy; Array Biopharma: Consultancy; Oncoceutics: Research Funding; Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Spatz Foundation: Research Funding; Therakos: Research Funding, Speakers Bureau; Huya Bioscience Int'l: Consultancy; MiRagen Therapeutics: Consultancy; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Rhizen Pharma: Research Funding; Allos (spectrum): Research Funding; Soligenics: Research Funding; Eisai: Research Funding; Kyowa Hakko Kirin, Co: Membership on an entity's Board of Directors or advisory committees, Research Funding. Daver:ImmunoGen: Other: clinical trial, Research Funding. O'Brien:Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding. Frankel:Stemline: Consultancy, Patents & Royalties, Research Funding. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

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Treatment of Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) in Pediatric Patients with Tagraxofusp, a CD123-Targeted Therapy

Blood ◽

10.1182/blood-2021-150393 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2317-2317

Author(s):

Naveen Pemmaraju ◽

Branko Cuglievan ◽

Joseph L Lasky ◽

Albert Kheradpour ◽

Nobuko Hijiya ◽

...

Keyword(s):

Bone Marrow ◽

Adverse Events ◽

Board Of Directors ◽

Research Funding ◽

Pediatric Patients ◽

Plasmacytoid Dendritic Cell ◽

Case Series ◽

Complete Response ◽

Retrospective Case ◽

Advisory Committees

Abstract BACKGROUND Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and clinically aggressive hematological malignancy that overexpresses CD123, the interleukin-3 (IL3) receptor alpha subunit. Although BPDCN predominantly affects older adults (median age of 65 years at diagnosis), cases of BPDCN have been reported across all age groups, including infants and children. There is limited data available in the literature on the efficacy and safety of treatments for pediatric patients with BPDCN. Tagraxofusp (TAG, SL-401) is a CD123-directed targeted therapy consisting of recombinant human IL3 linked to a truncated diphtheria toxin payload. A published multicohort prospective study, with prespecified multisystem endpoints, demonstrated the benefit of TAG in adult patients with untreated or relapsed BPDCN. Among the untreated patients, 72% had a complete response and 90% overall response rate; of these patients, 45% were bridged to stem cell transplantation. Adverse events included transaminase elevations, hypoalbuminemia, thrombocytopenia, and capillary leak syndrome (CLS). In a previous case report including 3 pediatric patients with BPDCN, TAG was well-tolerated without significant toxicities and showed encouraging initial clinical responses. TAG was FDA approved in 2018 for BPDCN treatment in adult and pediatric (≥2 years) patients and was recently approved in the EU as monotherapy for first-line treatment in adults. METHODS Here, we report on a multicenter, retrospective case series investigation involving pediatric patients diagnosed with BPDCN at 3 centers in the United States. All patients were treated with TAG according to local institutional guidelines as either first-line treatment (1L) or as a therapy for relapsed/refractory disease (R/R). Data was collected retrospectively via chart review and summarized descriptively. Assessments included tumor response to therapy, survival and safety (adverse events and laboratory abnormalities). RESULTS A total of 6 pediatric patients diagnosed with BPDCN and treated with TAG were included in this analysis. The median age for patients in this study was 15.5 years (range 10 - 21 years), and 4 of the 6 patients were female. Three patients were R/R and received systemic therapy prior to TAG administration, while 3 patients were treatment-naive. Four patients had bone marrow involvement, 2 patients had lymph node involvement, and all 6 patients had skin lesions at diagnosis. All patients received a TAG dose of 12 mcg/kg, with the exception of 1 patient who received 9 mcg/kg. At the time of data cut off, the number of cycles administered ranged from 1 to 4. TAG was well tolerated in these 6 patients. One patient experienced headaches, hot flashes, fatigue, and mouth sores, and low albumin was observed in one patient. No other adverse events were reported and CLS was not observed in these patients. One patient had a complete response to TAG therapy (bone marrow minimal residual disease negative), 2 patients had stable disease, and 3 patients did not have an observed response. In the three 1L patients, one patient had stable disease (no progression after 4 TAG cycles), and 1 patient with extensive disease (skin, bone marrow and central nervous system) had a complete response. Three patients bridged to a stem cell transplant (SCT); 2 were R/R and 1 was 1L. Median survival data for this cohort will be presented (5 of 6 patients remain alive). CONCLUSIONS This multicenter, retrospective case series of 6 pediatric patients with BPDCN expands our base of knowledge of BPDCN treatment in younger individuals. At the time of data cut off for this abstract, TAG, an approved treatment for BPDCN, was well tolerated in all patients. Treatment with TAG was associated with promising efficacy, including half of the patients with responses that allowed for bridging to SCT. Disclosures Pemmaraju: CareDx, Inc.: Consultancy; Plexxicon: Other, Research Funding; Samus: Other, Research Funding; ASH Communications Committee: Membership on an entity's Board of Directors or advisory committees; Aptitude Health: Consultancy; Springer Science + Business Media: Other; HemOnc Times/Oncology Times: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy; Bristol-Myers Squibb Co.: Consultancy; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; ASCO Leukemia Advisory Panel: Membership on an entity's Board of Directors or advisory committees; Sager Strong Foundation: Other; Cellectis S.A. ADR: Other, Research Funding; Daiichi Sankyo, Inc.: Other, Research Funding; DAVA Oncology: Consultancy; Roche Diagnostics: Consultancy; MustangBio: Consultancy, Other; Abbvie Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Celgene Corporation: Consultancy; Stemline Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; LFB Biotechnologies: Consultancy; Clearview Healthcare Partners: Consultancy; Protagonist Therapeutics, Inc.: Consultancy; Affymetrix: Consultancy, Research Funding; Incyte: Consultancy; Novartis Pharmaceuticals: Consultancy, Other: Research Support, Research Funding; ImmunoGen, Inc: Consultancy; Pacylex Pharmaceuticals: Consultancy. Hijiya: Novartis: Consultancy; Stemline Therapeutics: Consultancy. Stein: Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau; Stemline: Speakers Bureau.

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Diagnosis of Blastic Plasmacytoid Dendritic Cell Neoplasm By Using 10-Colour Flow Cytometry and Achievement of Remission By Hypercvad Therapy

Blood ◽

10.1182/blood.v124.21.2365.2365 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2365-2365 ◽

Cited By ~ 1

Author(s):

Uday Deotare ◽

Elizabeth Hyjek ◽

Anna Porwit ◽

Rumina Musani ◽

David Barth ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Overall Survival ◽

Dendritic Cell ◽

Research Funding ◽

Plasmacytoid Dendritic Cell ◽

Leukemic Cells ◽

Front Line ◽

Hla Dr ◽

Cell Neoplasm

Abstract Background: Although classified by WHO 2008 as belonging to the category “Acute myeloid leukemia and related precursor neoplasms”, Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) presents as an acute leukemia (AL) only in a minority of cases. There are only few studies describing the comprehensive immunophenotypic pattern of BPDCN in the bone marrow. Furthermore, given the rarity of this hematologic malignancy optimal frontline therapy is unclear. Patients and Methods: This retrospective analysis evaluates the diagnostic flow cytometry pattern and outcome of 9 patients who were diagnosed with BPDCN at the Princess Margaret Cancer Centre between December 2008 and June 2014. A four tube 10-color flow cytometry (FCM) panel has been used to correctly make the diagnosis of BPDCN in 6 patients, whereas a 5-colour panel was used in the remaining patients in conjunction with immunohistochemistry. The following markers were included in the10-color panel: Tube 1: CD65 FITC, CD13 PE, CD14 ECD, CD33 PC5.5, CD34 PC7, CD117 APC, CD7 A700, CD11b A750, CD16 PB, and CD45 KO; Tube 2: CD36 FITC, CD64 PE, CD56 ECD, CD33 PC5.5, CD34 PC7, CD123 APC, CD19 A700, CD38 A750, HLA-DR PB, and CD45 KO; Tube 3: CD71 FITC, CD11c PE, CD4 ECD, CD33 PC5.5, CD34 PC7, CD2 APC, CD10 A700, CD235a A750, CD15 PB, and CD45 KO; Tube 4:nuclear (n) TdT FITC, cytoplasmic (cyt.) MPO PE, CD14 ECD, CD33 PC5.5, CD34 PC7, cyt.CD79a APC, cyt.CD22 A700, CD19 A750, cyt.CD3 PB, and CD45 KO. Results: Median age was 66 years (range, 25 to 91 years); 3 patients were over the age of 70 years. Fifty-six percent were males. All presented with skin lesions and 78% presented each with lymphadenopathy and bone marrow involvement. Cytogenetics were poor-risk in 2 patients, intermediate-risk in 3 and unknown or inconclusive in 4. By 10-color FCM, leukemic cells were in the blast gate (CD45dim/low SSC) and were positive for CD4(bright), CD33(dim), CD56(heterogenous), CD123(bright), CD36, CD38, HLA-DR, CD71, but negative for CD10, CD11b, CD13, CD14, CD15, CD16, CD19, CD34, CD64, CD65, CD235a. Other markers, such as cyt.MPO, cyt.CD3, cyt.CD22 and nTdT were negative, while dim cyt.CD79a was seen in 3 cases. CD7 expression was found in 5 cases, whereas CD2 and CD117 were found in single cases only. BM involvement by BPDCN leukemic cells ranged from 27% to 92% of the marrow cellularity. Skin involvement showed dense infiltrate of cells with blastoid morphology and characteristic grenz zone. Seven patients received front-line induction therapy with HyperCVAD with an overall response rate of 86% (4 complete remissions (CR), 2 unconfirmed CRs). One patient died of multi-organ failure during induction. Three of 6 responders underwent planned allogeneic hematopoietic cell transplantation (HCT); 1 patient has since died of acute graft versus host disease (GVHD), whereas 2 are alive in remission with chronic GVHD, 12 and 14 months post transplant with complete donor chimerism. One transplant ineligible patient relapsed 22 months after achievement of CR1. Median follow-up of all patients was 12 months with a overall survival at 1 year of 59.3% for the entire group. Patients who underwent allogeneic HCT had overall survival at 1 year of 66.7% and for the chemotherapy group was 27.8% at 1 year.(p=0.34). Conclusion: An accurate diagnosis of BPDCN can be made by 10-colour FCM using a 4-tube acute leukemia panel. BPDCN demonstrates a characteristic pattern of antigen expression . Although front-line induction chemotherapy with HyperCVAD can yield high CR rates, allogeneic HCT should be performed in first CR for transplant eligible patients, as this appears to be required for long term durable remissions. For transplant ineligible or relapsed BPDCN patients, there is an unmet need for novel therapeutic agents. Disclosures Porwit: Beckman-Coulter: Speakers Bureau. Gupta:Novartis: Consultancy, Honoraria, Research Funding; Incyte Corporation: Consultancy, Research Funding.

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Transcriptomic Microarray Profile Analysis between Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) and TET2-Mutated Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood-2018-99-118674 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3899-3899

Author(s):

Hannah Beird ◽

Maliha Khan ◽

Feng Wang ◽

Mansour Alfayez ◽

Tianyu Cai ◽

...

Keyword(s):

Bone Marrow ◽

Dendritic Cell ◽

Research Funding ◽

Profile Analysis ◽

Plasmacytoid Dendritic Cell ◽

Skin Lesions ◽

Rank Test ◽

Copy Number Alterations ◽

Serum Cytokine ◽

Cell Neoplasm

Abstract Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic neoplasm involving skin lesions and disseminated disease into bone marrow, peripheral blood, and lymph nodes, characterized by poor clinical outcomes and no standard therapeutic approaches. BPDCN is characterized by the malignant proliferation of precursor plasmacytoid dendritic cells (pDCs). It is now classified by WHO 2016 as a separate entity under myeloid malignancies owing to its unique clinico-pathologic nature, greater understanding of its distinct clinical course, but with some noted clinical, morphologic, and molecular similarities to AML and myelodysplastic syndrome (MDS). One of the most common molecular mutations observed by next-generation sequencing in the vast majority of patients with BPDCN has been the presence of TET2 mutations and variants. Notably, somatic missense and truncating mutations in TET2 have been reported in patients with both BPDCN and AML, yet their differential responses to similar therapeutic regimens in clinical trial testing indicates that there are likely key underlying etiologies that are yet to be determined. Aims: We sought to investigate and identify critical differences between patients with BPDCN and AML at the molecular level, utilizing a series of advanced analyses including transcriptome microarray, serum multiplex immunoassays and cytokine analysis. Methods: In order to discern these differences, we profiled bone marrow, peripheral blood and serum samples from primary patients samples with BPDCN (N = 16) and TET2-mutated AML (AMLTET2m) (N = 9) using 3 different assays. We first ascertained somatic point mutations and copy number alterations of 300 genes in our BPDCN specimens using an in-house hematologic malignancy panel ("T300" panel). Next, we confirmed the prevalence of compound truncating TET2 mutations in patients with BPDCN and few copy number alterations in the genes profiled. We then used the transcriptome microarray (ThermoFisher Scientific ClariomTM D Pico Assay, and serum multiplex immunoassays (Cytokine/Chemokine/Growth Factor 45-Plex Human ProcartaPlex™ Panel 1 (ThermoFisher Scientific, formerly Affymetrix) with the addition of IL-3 Human ProcartaPlex™ Simplex Kit, formerly Affymetrix) to compare BPDCN specimens against those from TET2-mutated AML patients. Results: With the microarray analysis, we found 920 genes to be up-regulated and 791 genes down-regulated in BPDCN specimens as compared to AMLTET2m. We corroborated known differentially expressed marker genes: higher levels of IL3Ra and TCL1A and lower levels of MPO in BPDCN as compared to AMLTET2m specimens. Genes specific to dendritic cells (PTPRS, LTK, LAMP5) were highly expressed in BPDCN than in AMLTET2m specimens. Of interest, two of these genes, PTPRS and LTK, provide possible links to the skin lesions as PTPRS is implicated in the progression of melanoma and LTK is involved in pigmentation of melanocytes. The serum cytokine profile analysis showed significantly elevated levels of eotaxin and RANTES in the BPDCN cohort as compared to the AMLTET2m cohort (Figure 1a,b). Both of these are implicated in allergic and autoimmune reactions by behaving as eosinophil chemo-attractants. Along with the higher levels of PTPRS and dendritic nature of the tumor cells, these findings suggest a possible autoimmune background which exists in the context of disease. Conclusions: In this novel analysis, we observed elevated levels of eotaxin and RANTES in patients with BPDCN as compared to AMLTET2m. These findings may represent an important aspect of pDC functioning even outside of BPDCN, as pDCs may contribute to the pathogenesis of systemic lupus erythematosus (SLE), an autoimmune disorder with hallmark cutaneous lesions. Moreover, autoimmune pathologies have been hypothesized to damage the bone marrow and induce destruction of myeloid precursor cells. This may incorporate some of the dendritic cell nature since in its natural context, as pDCs serve to recognize foreign particles such as viruses and synthetic oligonucleotides through Toll-like Receptors TLR7/9. These findings suggest that further study into these markers are warranted in patients with BPDCN. Figure 1. Differential serum cytokine levels between BPDCN and AMLTET2m (a) Eotaxin (pg/mL), Wilcox rank test P < 0.01 (b) RANTES (pg/mL), Wilcox rank test P < 0.05. Disclosures Konopleva: Stemline Therapeutics: Research Funding. Pemmaraju:stemline: Consultancy, Honoraria, Research Funding; plexxikon: Research Funding; SagerStrong Foundation: Research Funding; daiichi sankyo: Research Funding; celgene: Consultancy, Honoraria; Affymetrix: Research Funding; samus: Research Funding; cellectis: Research Funding; abbvie: Research Funding; novartis: Research Funding.

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Molecular Characterization Using Oncoscan Chromosome Microarray in an International Cohort of 51 Patients with Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN)

Blood ◽

10.1182/blood-2021-152922 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3497-3497

Author(s):

Eli Williams ◽

Stefano A Pileri ◽

Maria Rosaria Sapienza ◽

Carlos Barrionuevo ◽

Carlos Bacchi ◽

...

Keyword(s):

Board Of Directors ◽

Copy Number ◽

Research Funding ◽

Plasmacytoid Dendritic Cell ◽

Chromosome 9 ◽

Single Nucleotide Variants ◽

Advisory Committees ◽

Single Nucleotide ◽

Cell Neoplasm ◽

Chromosome Microarray

Abstract Introduction Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy with multi-organ and frequent skin involvement, and poor clinical outcomes. Based on the limited available data, the estimated incidence is 0.44% of all hematologic malignancies, representing less than 1% of acute leukemias, and 0.7% of cutaneous lymphomas. Due to the rarity of this entity, there have been relatively few studies characterizing the molecular profile of BPDCN. We examined a cohort of 51 patients with BPDCN using OncoScan chromosome microarray, which provides genome-wide copy number abnormality (CNA) analysis. Methods An international cohort of BPDCN cases were collected from centers in Brazil (Laboratorio de Patologia, Botucatu), Swtizerland (University of Zurich), France (Hospital St. Louis, Paris), Peru (Instituto Nacional de Enfermedades Neoplasicas, Lima), Canada (Department of Pathology, University of Montreal), Italy (Derpartment of Pathology, University of Bologna), and US (Department of Pathology - The Ohio State University, Department of Hematopathology - MD Anderson Cancer Center; and Department of Pathology - University of Virginia). A total of 58 tissue blocks from 51 patient samples were retrieved. The diagnosis of BPDCN was done and confirmed by at least three independent hematopathologists or dermatopathologists in accordance with the WHO classification (Lyon 2017). For the purpose of the molecular analysis substratification, cases were classified as 'BPDCN' if they were positive for TCF4, and 'BPDCN-like' if they were negative for TCF4. Immunohistochemistry for CD123, CD4, and CD56 was performed in all cases. Exclusion criteria included expression of MPO, lysozyme, CD3, CD19, CD20, CD22, and/or EBV. DNA was extracted from FFPE samples via standard techniques and processed on OncoScan CNV Plus microarray (ThermoFisher Scientific) according to manufacturer's recommended protocol. Copy number abnormalities and select single nucleotide variants and insertions/deletions (74 mutations in 9 genes) were analyzed on Chromosome Analysis Suite software (ChAS v4.1; ThermoFisher Scientific). Additional analysis was performed using Nexus Copy Number (BioDiscovery, version 10.0). Results To date, we have successfully analyzed 45 cases of BPDCN with Oncoscan, revealing widespread CNA in the vast majority of cases (44/45; 98%). Alterations of chromosome 9 were common in this cohort, particularly CNAs involving CDKN2A/B at 9p21.3. Twenty-five cases (56%) demonstrated CNA including CDKN2A/B, with ten of these cases demonstrating a homozygous loss of CDKN2A/B (22%). Alterations of chromosome 13 were also frequently detected with loss of RB1 (located at 13q14.2) detected in 24 cases (53%). The RUNX1 gene (21q22.12) was a common target of CNAs in this cohort, seen in nine cases (20%). Eight of these cases showed a copy number gain of RUNX1, which is a recurrent finding in a variety of hematological malignancies, particularly myeloid neoplasms. The remaining case with RUNX1 CNA showed a focal, homozygous loss of the gene, demonstrating that dysregulation of RUNX1 through CNA is a common event in BPDCN. We observed frequent deletions of ETV6 (53%), IKZF1 (33%), and TP53(16%) in our cohort. The ARHGAP26 gene (5q31.3), which is associated primarily with juvenile myelomonocytic leukemia, was included in CNA in 13 cases (29%), with both gains and losses observed in this cohort. Oncoscan can detect a limited number of single nucleotide variants in nine genes that are frequently mutated in cancers (BRAF, EGFR, IDH1, IDH2, KRAS, NRAS, PIK3CA, PTEN, and TP53). Mutations were detected in ten cases (22%), with NRAS and TP53 variants detected in three cases each and KRAS and IDH2 variants detected in two cases each. Conclusions Our preliminary data demonstrates complex genomic alterations in BPDCN, with the RB1 locus on chromosome 13, the CDKN2A/B locus on chromosome 9, and the ETV6 locus on chromosome 12 most commonly detected. However, widespread genomic alterations were detected involving a variety of cancer-associated genes further characterizing CNA in BPDCN. Analysis of additional BPDCN cases is progress. Disclosures Khoury: Kiromic: Research Funding; Angle: Research Funding; Stemline Therapeutics: Research Funding. Porcu: Viracta: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Daiichi: Honoraria, Research Funding; Kiowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Spectrum: Consultancy; DrenBio: Consultancy. Gru: StemLine: Honoraria, Research Funding, Speakers Bureau; CRISPT Therapeutics: Research Funding; Innate Pharma: Research Funding.

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Education on Blastic Plasmacytoid Dendritic Cell Neoplasm Significantly Impacts the Interdisciplinary Physician Team

Blood ◽

10.1182/blood-2021-145378 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3021-3021

Author(s):

Lauren Willis ◽

Anthony S. Stein ◽

Kendra Sweet ◽

Joan Guitart ◽

Naveen Pemmaraju ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Plasmacytoid Dendritic Cell ◽

Learning Objective ◽

Advisory Committees ◽

Cutaneous Manifestations ◽

Cell Neoplasm ◽

Rare Malignancy ◽

Additional Education ◽

Physician Team

Abstract Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive malignancy that originates from precursors of plasmacytoid dendritic cells. BPDCN is a difficult disease to diagnose and manage and it is often misdiagnosed or underreported. The literature widely supports the need for an interdisciplinary team of physicians with specialized expertise to care for patients with BPDCN, such as dermatologists, pathologists, hematologists/oncologists (hem/oncs), stem cell transplant physicians and others. Aim: The objective of this study was to determine if online education could improve the knowledge of the interdisciplinary physician team members about BPDCN as well as their skills and confidence diagnosing this rare malignancy. Methods: Dermatologists, pathologists, and hem/oncs participated in a series of 6 live continuing medical education (CME)-certified activities, after which the recorded content was posted online as a single online enduring CME-certified activity. Content for the CME activities was developed by a multidisciplinary group of BPDCN experts and was delivered through an approximately 1-hour lecture. Data presented here is for the online enduring activity only. Educational effect was assessed using a repeated-pair design with pre-/post-assessment. Three multiple choice questions assessed knowledge/skills, and 1 question rated on a Likert-type scale assessed confidence. A paired samples t-test was conducted for significance testing on overall average number of correct responses and for confidence rating, and a McNemar's test was conducted at the question and learning objective level (5% significance level, P <.05). Data were collected from December 10, 2020 to May 3, 2021. Results: There were 246 dermatologists, 302 pathologists, and 316 hem/oncs included in this analysis, for overall n=864. PRACTICE SETTING: Dermatologists: 57% community, 15% academic, 13% government, 15% other; Pathologists: 37% community, 37% other, 23% academic, 4% government; Hem/Oncs: 48% community, 31% academic, 14% government, 7% other.OVERALL RESULTS: Overall 46% of dermatologists, 42% of pathologists, and 48% of hem/oncs improved their knowledge/skills related to BPDCN (P <.001 for all), showing a relative increase in responses correct from pre- to post-CME of 67% for dermatologists, 38% for pathologists, and 45% for hem/oncs.CONFIDENCE: 50% of dermatologists, 50% of pathologists, and 49% of hem/oncs had a measurable increase in confidence (P <.001 for all), resulting in 30% of dermatologists, 31% of pathologists, and 36% of hem/oncs who were mostly or very confident diagnosing BPDCN post-CME (9%, 14%, 17% pre-CME, respectively).The Table shows the mean percentage of correct responses by learning objective and the question used to test each learning objective. 20%/54% of dermatologists, 22%/57% of pathologists, and 20%/55% of hem/oncs improved/reinforced their knowledge of the most common cutaneous manifestations of BPDCN and 26%, 22%, 25% need additional education, respectively. CME improved skills ordering tests to diagnose BPDCN, however 57% of dermatologists, 58% of pathologists, and 45% of hem/oncs demonstrate a need for additional education about stains that can aid in diagnosing BPDCN. Conclusions: This online CME-certified educational activity led to statistically significant improvements in the knowledge and skills of dermatologists, pathologists, and hem/oncs about BPDCN as well as their skills and confidence diagnosing this rare malignancy. The results indicate that unique educational methodologies which are available on-demand can be effective tools for advancing clinical decision making. Additional education is recommended on the topics of cutaneous manifestations of BPDCN and case-based education to improve skills diagnosing BPDCN. Acknowledgements: This CME activity was supported by an independent educational grant from Stemline Therapeutics, Inc. Reference: https://www.medscape.org/viewarticle/942245 Figure 1 Figure 1. Disclosures Stein: Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau; Stemline: Speakers Bureau. Sweet: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; AROG: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Guitart: Miragen, Kyowa Kirin: Consultancy; Galderma: Consultancy, Research Funding; Solygenix, Elorac, Nanostring: Research Funding. Pemmaraju: LFB Biotechnologies: Consultancy; Aptitude Health: Consultancy; Stemline Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Incyte: Consultancy; Daiichi Sankyo, Inc.: Other, Research Funding; Plexxicon: Other, Research Funding; Springer Science + Business Media: Other; Cellectis S.A. ADR: Other, Research Funding; CareDx, Inc.: Consultancy; Affymetrix: Consultancy, Research Funding; Roche Diagnostics: Consultancy; Novartis Pharmaceuticals: Consultancy, Other: Research Support, Research Funding; Blueprint Medicines: Consultancy; Celgene Corporation: Consultancy; DAVA Oncology: Consultancy; Sager Strong Foundation: Other; ASCO Leukemia Advisory Panel: Membership on an entity's Board of Directors or advisory committees; ASH Communications Committee: Membership on an entity's Board of Directors or advisory committees; MustangBio: Consultancy, Other; Abbvie Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; HemOnc Times/Oncology Times: Membership on an entity's Board of Directors or advisory committees; Samus: Other, Research Funding; Bristol-Myers Squibb Co.: Consultancy; Protagonist Therapeutics, Inc.: Consultancy; Clearview Healthcare Partners: Consultancy; ImmunoGen, Inc: Consultancy; Pacylex Pharmaceuticals: Consultancy. Poligone: Stemline, Helsinn, Kyowa Kirin: Consultancy; Soligenix, Miragen, Helsinn, Bioniz: Research Funding; Stemline, Therakos, Regeneron: Speakers Bureau.

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Pre-Clinical Studies of Anti-CD123 CAR-T Cells for the Treatment of Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN)

Blood ◽

10.1182/blood.v128.22.4039.4039 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4039-4039 ◽

Cited By ~ 12

Author(s):

Tianyu Cai ◽

Roman Galetto ◽

Agnès Gouble ◽

Julianne Smith ◽

Antonio Cavazos ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

Dendritic Cell ◽

Research Funding ◽

Plasmacytoid Dendritic Cell ◽

Newly Diagnosed ◽

Car T Cells ◽

Car T ◽

Cell Neoplasm

Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematologic malignancy which originates from the precursors of plasmacytoid dendritic cells. Data on the biology of BPDCN are limited, patient outcomes have historically been poor and there remains no established standard of care. CD123/IL3Rα is overexpressed in nearly 100% of patients with BPDCN. Considering the urgent unmet medical need for patients with BPDCN, targeting CD123 emerged as an attractive therapeutic target given its accessibility (cell surface) and differential expression (markedly over-expressed on BDPCN blasts as compared to normal hematopoietic stem cell compartment). UCART123 (CD123CAR/RQR8+_TCRαβ-_T-cells) are genetically modified allogeneic T-cells (obtained from healthy volunteer donors by leukapheresis) containing (i) an anti-CD123 CAR (CD123 scFv-41BB-CD3z) and (ii) an RQR8 depletion ligand that confers susceptibility to rituximab. The cell surface expression of the T cell receptor (TCR) is depleted through the inactivation of the TCRa constant (TRAC) gene using Cellectis' TALEN® technology. In this study, we examined efficacy of this first allogenic anti-CD123 CAR-T cells in pre-clinical models of BPDCN. We first analysed the level of expression of CD123 in the bone marrow of 8 patients with newly diagnosed BPDCN, and compared with CD123 expression on blasts of 28 newly diagnosed AML patients. CD123 expression levels were significantly higher in BPDCN (mean fluorescence intensity (MFI) range 3,484-17,937) compared to AML (MFI range 360-5,073) (p<0.01). In vitro cytotoxic activity of UCART123 cells was evaluated by co-culturing UCART123 cells with primary human BPDCN, at a 10:1 effector to target ratio, using flow cytometry. The results show significant cytotoxic activity of UCART123 cells against BPDCN samples compared to cells co-cultured with non-transduced TCRab- T-cells (NTD) (Fig. 1A). We next evaluated antigen-specific UCART123 cell degranulation by staining of CD107α, a lysosomal associated membrane protein residing in cytolytic granule membranes. The results indicated that specific degranulation of UCART123 cells is observed upon co-culture with CD123 (+) target cells. The capacity of UCART123 cells to secrete cytokines, in particular IFNγ, in response to specific stimulation with CD123 (+) BPDCN cells was examined using a BioLegend's LEGENDplexTM assay. UCART123 cells stimulated by CD123 (+) BPDCN cells, but not NTD cells, secreted high levels of IFNγ in the culture supernatants (Fig. 1B). To evaluate in vivo anti-tumor activity of UCART123 cells, we established patient-derived xenograft (PDX) from a patient with relapsed BPDCN in NSG-SGM3 mice. Upon engraftment, mice were randomized into 4 groups (9 mice/group). Mice received either a single tail vein injection of vehicle, 10×106 NTD T-cells, and 3×106 or 10×106 UCART123 cells. All mice in vehicle-treated group and in the group that received 10×106 NTD cells died by day 53, with high tumor burden of BPDCN detected in peripheral blood, spleen and bone marrow. Both cell doses of UCART123 significantly extended mice survival (Fig. 1C) and reduced or eliminated circulating BPDCN cells. 57 days after UCART123 cells injection, one mouse from UCART123 10×106 group was sacrificed. UCART123 cells were detected in spleen (16.4% CAR+ cells) and bone marrow (1.1% CAR+ cells) using human CD5 antibody or CD123-Fc protein. In summary, UCART123 causes specific killing of BPDCN cells, associated with antigen-specific T-cell degranulation and robust levels of IFNg production. Our preliminary data indicate persistence of UCART123 cells in vivo in an NSG-S model of primary BPDCN. Most importantly, UCART123 therapy results in BPDCN eradication and long-term disease-free survival in primary BPDCN PDX mice. Additional PDX studies are ongoing and will be presented. These results demonstrate pre-clinical proof-of principle of high anti-BPDCN activity of UCART123 allogeneic CAR T-cells, and warrant further clinical testing of this approach in human clinical trials in BPDCN. Disclosures Galetto: Cellectis SA: Employment. Gouble:Cellectis: Employment. Smith:Cellectis SA: Employment. Lane:Stemline Therapeutics: Research Funding; N-of-1: Consultancy. Guzman:Cellectis: Research Funding. Konopleva:Cellectis: Research Funding; Calithera: Research Funding.

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The Metabolomic Status of the Differentiating Myeloid Lineage in MDS with Low and High Bone Marrow Blast Counts

Blood ◽

10.1182/blood-2020-140468 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 32-33

Author(s):

Aikaterini Poulaki ◽

Theodora Katsila ◽

Ioanna E Stergiou ◽

Stavroula Giannouli ◽

Jose Carlos Gόmez Tamayo ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Warburg Effect ◽

Research Funding ◽

Metabolic Reprogramming ◽

Negative Ion ◽

Advisory Committees ◽

Myeloid Lineage ◽

Epigenetic Modifier ◽

Cellular Fate

Despite its major role in cellular biology, metabolism has only recently acquired a principal role in the research of the most profound cellular cycle disturbance, cancerous transformation. Myelodysplastic syndromes (MDS), a massively heterogeneous group of Hematopoietic Stem/ Progenitor Cell (HSC/HPC) disorders lie at the interface of normal differentiation and malignant transformation and have thus drew great attention due to their polymorphic presentation and elusive pathophysiology. Failure to establish a direct etiopathogenic relationship with specific genetic aberrations, along with the novel finding of a highly deregulated HIF1 activity by several unrelated research groups worldwide, including ours, urged us to investigate the metabolomic status of human bone marrow derived differentiating myeloid lineage in comparison with one another as well as with control samples. BM aspiration samples collected from 14 previously untreated MDS patients (10 patients with <5% (1 SLD, 8MLD, 1del5q, group 1- G1) and 4 with >5% BM blasts (2 EB1, 2 EB2group 2 - G2)) and 5 age matched controls. Myeloid lineage cells were isolated through ficoll bilayer protocol. All samples contained homogenous myeloid lineage subpopulations, assessedthrough optical microscopy. Two different metabolite extraction protocols were applied. The one with the best metabolites yield (50% MeOH, 30% ACN, 20% H2O) was chosen. LC-MS/MS analysis was performed using UPLC 1290 system (Agilent Technologies) coupled to a TripleTOF 5600+ mass spectrometer (SCIEX) equipped with SWATH acquisition, SelexION technology and an electrospray ionization source (ESI). A threshold of a minimum of three samples expressing a given metabolite was set against data sparsity. Data tables were scaled by data centering and setting unit variance. Log2 Foldcalculation and PLS analysis were performed for the two datasets (positive and negative ion-modes). R2 and Q2 for positive ion-mode and negative-ion mode analyses were determined. Both datasets were merged in a unique data table by taking into account maximum absolute log2 foldvalues, when a metabolite was found in both datasets. Warburg effect was evidently present in both the G1 and G2 vs control comparisons, yet the role of this stem like aerobic glycolysis seems markedly different in the two groups. While in the G2 group it serves to rescue glucose from complete burn in the mitochondrion and thus shuts it towards nucleotide synthesis (Pentose Phosphate Pathway found upregulated) with the added benefit of increased reduced Glutathione synthesis and improved redox state, in the G1 group proves detrimental. This greatly variable effect of the same phenomenon in the cellular fate lies upon the quality and functionality of the cellular mitochondrial content. G2 precursors presented functional mitochondrial (decreased NAD/NADH and FAD/FADH2) contrary to the G1 ones (Table). Failing TCA cycle, with increased NAD/NADH and FAD/FADH2 ratios and markedly increased ADP/ATP levels leads to FAs accumulation due to failure of effective adequate β oxidation. The uncontrolled increase in the NAD/NADH ratio stimulates upper glycolysis into a turbo mode further increasing the ADP/ATP, depleting cellular energy contents, engaging it to a never-ending deadly metabolism. The enormous abundance of upper glycolytic intermediates is relieved through phospholipid and ceramide synthesis, all found massively upregulated in both the MDS vs control yet also in the G1 vs G2 comparisons. FAs, mostly phospholipid and ceramide accumulation, interrupt the mitochondrial membrane lipidome further incapacitating metabolic integrity and inducing their autophagic degradation which further stimulates the Warburg effect. This type of metabolic reprogramming is eventually targeted to epigenetic modifier production, increased S-adenosyl-methionine, the major methyl group donor, 2-HydroxyGlutarate, a potent epigenetic modifier and notorious oncometabolite, Acetyl-Lysine, the major acetyl- group donor, even glutathione. We therefore present a model of an uncontrolled Warburg effect which in the G1 group confers premature death of the hematopoietic precursors, the ineffective hematopoiesis of MDS. Yet, under the pressure of the vastly upregulated epigenetic modifiers cellular fate changes, the G1 precursors adapt and transform to the G2 ones yet eventually to Acute Myeloid Leukemia blasts. Table Disclosures Vassilopoulos: Genesis pharma SA: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

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p53 Mediated Bone Marrow Mesenchymal Stem Cell Expansion Supports Acute Myeloid Leukemia Development

Blood ◽

10.1182/blood-2019-127245 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 523-523

Author(s):

Rasoul Pourebrahimabadi ◽

Zoe Alaniz ◽

Lauren B Ostermann ◽

Hung Alex Luong ◽

Rafael Heinz Montoya ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Osteoblast Differentiation ◽

Hematopoietic Cells ◽

Advisory Committees ◽

Equity Ownership ◽

Mdm2 Inhibitor ◽

Acute Myeloid

Acute myeloid leukemia (AML) is a heterogeneous disease that develops within a complex microenvironment. Reciprocal interactions between the bone marrow mesenchymal stem/stromal cells (BM-MSCs) and AML cells can promote AML progression and resistance to chemotherapy (Jacamo et al., 2014). We have recently reported that BM-MSCs derived from AML patients (n=103) highly express p53 and p21 compared to their normal counterparts (n=73 p<0.0001) (Hematologica, 2018). To assess the function of p53 in BM-MSCs, we generated traceable lineage specific mouse models targeting Mdm2 or Trp53 alleles in MSCs (Osx-Cre;mTmG;p53fl/fl and Osx-Cre;mTmG;Mdm2fl/+) or hematopoietic cells (Vav-Cre;mTmG;p53fl/fl and Vav-Cre;mTmG;Mdm2fl/+). Homozygote deletion of Mdm2 (Osx-Cre;Mdm2fl/fl) resulted in death at birth and displayed skeletal defects as well as lack of intramedullary hematopoiesis. Heterozygote deletion of Mdm2 in MSCs was dispensable for normal hematopoiesis in adult mice, however, resulted in bone marrow failure and thrombocytopenia after irradiation. Homozygote deletion of Mdm2 in hematopoietic cells (Vav-Cre;Mdm2fl/fl) was embryonically lethal but the heterozygotes were radiosensitive. We next sought to examine if p53 levels in BM-MSCs change after cellular stress imposed by AML. We generated a traceable syngeneic AML model using AML-ETO leukemia cells transplanted into Osx-Cre;mTmG mice. We found that p53 was highly induced in BM-MSCs of AML mice, further confirming our findings in primary patient samples. The population of BM-MSCs was significantly increased in bone marrow Osx-Cre;mTmG transplanted with syngeneic AML cells. Tunnel staining of bone marrow samples in this traceable syngeneic AML model showed a block in apoptosis of BM-MSCs suggesting that the expansion of BM-MSCs in AML is partly due to inhibition of apoptosis. As the leukemia progressed the number of Td-Tomato positive cells which represents hematopoietic lineage and endothelial cells were significantly decreased indicating failure of normal hematopoiesis induced by leukemia. SA-β-gal activity was significantly induced in osteoblasts derived from leukemia mice in comparison to normal mice further supporting our observation in human leukemia samples that AML induces senescence of BM-MSCs. To examine the effect of p53 on the senescence associated secretory profile (SASP) of BM-MSCs, we measured fifteen SASP cytokines by qPCR and found significant decrease in Ccl4, Cxcl12, S100a8, Il6 and Il1b upon p53 deletion in BM-MSCs (Osx-Cre;mTmG;p53fl/fl) compared to p53 wildtype mice. To functionally evaluate the effects of p53 in BM-MSCs on AML, we deleted p53 in BM-MSCs (Osx-Cre;mTmG;p53fl/fl) and transplanted them with syngeneic AML-ETO-Turquoise AML cells. Deletion of p53 in BM-MSCs strongly inhibited the expansion of BM-MSCs in AML and resulted in osteoblast differentiation. This suggests that expansion of BM-MSCs in AML is dependent on p53 and that deletion of p53 results in osteoblast differentiation of BM-MSCs. Importantly, deletion of p53 in BM-MSCs significantly increased the survival of AML mice. We further evaluated the effect of a Mdm2 inhibitor, DS-5272, on BM-MSCs in our traceable mouse models. DS-5272 treatment of Osx-cre;Mdm2fl/+ mice resulted in complete loss of normal hematopoietic cells indicating a non-cell autonomous regulation of apoptosis of hematopoietic cells mediated by p53 in BM-MSCs. Loss of p53 in BM-MSCs (Osx-Cre;p53fl/fl) completely rescued hematopoietic failure following Mdm2 inhibitor treatment. In conclusion, we identified p53 activation as a novel mechanism by which BM-MSCs regulate proliferation and apoptosis of hematopoietic cells. This knowledge highlights a new mechanism of hematopoietic failure after AML therapy and informs new therapeutic strategies to eliminate AML. Disclosures Khoury: Angle: Research Funding; Stemline Therapeutics: Research Funding; Kiromic: Research Funding. Bueso-Ramos:Incyte: Consultancy. Andreeff:BiolineRx: Membership on an entity's Board of Directors or advisory committees; CLL Foundation: Membership on an entity's Board of Directors or advisory committees; NCI-RDCRN (Rare Disease Cliln Network): Membership on an entity's Board of Directors or advisory committees; Leukemia Lymphoma Society: Membership on an entity's Board of Directors or advisory committees; German Research Council: Membership on an entity's Board of Directors or advisory committees; NCI-CTEP: Membership on an entity's Board of Directors or advisory committees; Cancer UK: Membership on an entity's Board of Directors or advisory committees; Center for Drug Research & Development: Membership on an entity's Board of Directors or advisory committees; NIH/NCI: Research Funding; CPRIT: Research Funding; Breast Cancer Research Foundation: Research Funding; Oncolyze: Equity Ownership; Oncoceutics: Equity Ownership; Senti Bio: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Eutropics: Equity Ownership; Aptose: Equity Ownership; Reata: Equity Ownership; 6 Dimensions Capital: Consultancy; AstaZeneca: Consultancy; Amgen: Consultancy; Daiichi Sankyo, Inc.: Consultancy, Patents & Royalties: Patents licensed, royalty bearing, Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Consultancy. OffLabel Disclosure: Mdm2 inhibitor-DS 5272

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Transplantation for Congenital Sideroblastic Anaemia Is Feasible and Offers Outcomes Comparable to Other Transfusion Dependent Anaemias. a Joint Retrospective Study of the Paediatric Diseases and Severe Aplastic Anaemia Working Parties (PDWP/SAAWP) of EBMT

Blood ◽

10.1182/blood-2020-142397 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 45-47

Author(s):

Josu de la Fuente ◽

Dirk-Jan Eikema ◽

Paul Bosman ◽

Robert F Wynn ◽

Miguel Díaz ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Graft Failure ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Response To Treatment ◽

Variable Response ◽

Advisory Committees ◽

Grade Ii

Congenital sideroblastic anaemias (CSA) are a rare group of disorders characterized by the presence of pathologic iron deposits within the mitochondria of erythroid precursors (ring sideroblasts) in the bone marrow due to heterogenous germline mutations leading to defects in mitochondrial heme synthesis, iron-sulfur (Fe-S) cluster biogenesis, or protein synthesis. Patients present with anaemia and relative reticulocytopenia, and systemic iron overload secondary to chronic ineffective erythropoiesis, leading to end-organ damage. The disease is heterogenous underlying the genetic variability and the variable response to treatment. Although a number of CSA patients have received a bone marrow transplant, the outcomes and toxicities are not known. This status makes it very difficult to understand the role of BMT in the management of CSA. A search in the EBMT database identified 28 patients receiving a HSCT for CSA between 1998 to 2018 by 24 participating centres. The median year of transplantation was 2014 (IQR 2004-2016). The distribution was equal between males (n=14) and females (n=14). The median age at transplantation was 7 years of age (3-10 years). Fifteen patients had a sibling HSCT (88%), one a family matched donor HSCT (6%) and one an unrelated matched (6%), the type of transplant being unknown in others (n=11). The source of stem cells was bone marrow in 20 cases (74%), peripheral blood in 4 cases (15%), cord blood in 2 (7%) and combined bone marrow and cord in one (4%). Five cases had a Bu/Cy based conditioning regimen, 4 had Bu/fludarabine based regimen and three fludarabine/treosulfan based conditioning with the rest having a variety of approaches. Eighty-six percent of cases had serotherapy with ATG or alemtuzumab. The median follow-up was 31.6 months (95% CI, 12.2-74.1%). The overall survival at 12 and 24 months was 88% (76-100) and 82% (66-99), respectively (figure 1). The median neutrophil engraftment was 18 (15-21) days and platelet engraftment >20 x 109/L was 29 (20-51) days, with a graft failure incidence of 7% (0-17) at 12 months. Two patients suffered from VOD. There were four deaths, three of which were related to transplant complications. The event free survival (survival without graft failure, relapse and second transplant) at 12 and 24 months was 85% (72-99) (figure 2). Six patients developed acute GvHD grade II and one case grade III; giving a grade II/III incidence of 28% (10-46). There was one case of limited and one of chronic GvHD, giving an incidence of 11% (0-26%) at 12 months and 24 months. In conclusion, whilst HSCT for CSA is a rare occurrence, these data demonstrate that HSCT for this condition is feasible and the outcomes are in keeping with those obtained for transplantation for transfusion dependent anaemias during the same time-period. Disclosures Handgretinger: Amgen: Honoraria. Moraleda:Gilead: Consultancy, Other: Travel Expenses; Jazz Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy, Other: Travel Expenses; Sandoz: Consultancy, Other: Travel Expenses; Takeda: Consultancy, Other: Travel Expenses. Risitano:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alnylam: Research Funding; Alexion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Jazz: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Samsung: Membership on an entity's Board of Directors or advisory committees; Amyndas: Consultancy; RA pharma: Research Funding; Biocryst: Membership on an entity's Board of Directors or advisory committees; Apellis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Achillion: Membership on an entity's Board of Directors or advisory committees; Pfizer: Speakers Bureau. Peffault De Latour:Amgen: Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Apellis: Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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