TET Dioxygenase Inhibition As a Therapeutic Strategy in TET2 Mutant Myeloid Neoplasia

TET2 is one of the most commonly mutated genes in myeloid neoplasia. Somatic TET2 mutations (TET2MT) cause complete or partial loss of enzymatic activity. TET2 (along with TET1/3) are Fe2+ and αKG-dependent DNA-dioxygenases that catalyze the oxidation of 5mC→5hmC→5fC→5caC. Ultimately, 5hmC generated by TET2-dioxygenase passively prevents maintenance methylation due to DNA methyltransferase's inability to recognize 5hmC. Alternatively, demethylation may also be a result of base excision repair of fC and caC. TET2MT can serve as therapeutic targets because they are often initiating lesions and present in a large fraction of patients. In this study, a comprehensive analysis of the configurations of TET2MT in myeloid neoplasia including MDS (n=1809) and AML (n=808), showed a remarkable exclusivity with 2-HG producing neomorphic IDH1/2MT (Fig.A). TET2 expression in 97 healthy and 909 MDS/MPN or AML patients from two independent studies showed that IDH1/2MT cases have significantly higher TET2 expression and were also mutually exclusive in cases with lower TET2 expression. Doxycycline inducible expression of IDH1MT led to profound growth inhibition of both a natural TET2MT cell line SIG-M5 and engineered TET2-/- K562, while the effect to parental K562 was mild (Fig.B-E). These observations suggest that mutual exclusivity of TET2MT and IDH1/2MT is due to synthetic lethality of TET2MT cell caused by 2-HG production, rather than redundancy of the consequences of IDH1/2MT and TET2MT. In TET2MT cell 2-HG further inhibit the residual TET-activity (TET1/3) and may cause synthetic lethality to cells with affected TET2 function. SIG-M5 cells expresses significant amount of TET3 while negligible levels of TET1. The reliance on relative compensation through residual TET3 activity has been confirmed in cells by inducible TET3 knockdown. We hypothesized that transient suppression of the residual DNA dioxygenase activity with inhibitors may selectively eliminate TET2-deficient clones. The known TET inhibitors 2-HG, N-oxalylglycine (NOG) and dimethyl methyl fumarate (DMF) lack specificity, pharmacologic properties and potency. Based on the results of in silico docking simulations, we designed and synthesized 16 aKG derivatives. Among them, TETi76 showed best inhibition effect in both TET activity and cell growth of TET2 low expressing cell. TETi76 binds to the α-KG co-factor site of TET2 that principally involves H1801, H1381 and S1898. These amino acids are conserved in all three TET enzymes. To test the in vitro efficacy and specificity of TETi, we used several human myeloid cell lines that harbor loss of function TET2 mutations or constitutively express low TET2 levels as well as bone marrow derived from Tet2+/+, Tet2+/- and Tet2-/- mice (Fig.F-G). Results showed that cells with low 5hmC level were more sensitive to TETi76 treatment. Specificity of TETi76 was further confirmed by RNAseq analyses of TETi76 treated K562, TET2-/- K562 and parental control cells. Moreover, TETi treatment did not appear to affect the function of α-KG-dependent histone dioxygenases. Mechanistically, treatment of SIG-M5 cells with TETi76 induced early and late stages of apoptotic cell death, a finding further confirmed by PARP1 and caspase-3 cleavage. RNAseq analyses of SIGM5 cells after treatment with TETi demonstrated a significant down-regulation of genes involved in transcription and peptide elongation, consistent with the consequences of TET inhibition. Interestingly, we also observed significant up-modulation of oxidative stress response pathway genes consistent with the inhibition of dioxygenases. In particular, TETi76 treatment induces 8-fold increase of oxidative stress sensor NQO1 a NRF2 target gene. To further probe the effects of TETi76 on TET2 deficient cells, Tet2MT/Tet2WT BM cells were co-cultured at fixed ratios to mimic the evolving Tet2MT clones. TETi76 effectively eliminated otherwise dominating Tet2MT cells (Fig.H). To determine the in vivo effects of TETi e.g., on elimination of Tet2MT clones, we performed bone marrow competitive reconstitution assays in PEP mice. TETi treatment selectively restricted the proliferative advantage of Tet2MT HSC compared to vehicle control where, as expected, TET2 mutant clones took over the WT cells. In clinical applications, TET inhibitors may constitute a new class of agents to be used in a targeted fashion in TET2 mutant neoplasia. Figure. Disclosures Meggendorfer: MLL Munich Leukemia Laboratory: Employment. Abazeed:Bayer AG: Honoraria, Other: Travel Support, Research Funding; Siemens: Research Funding. Sekeres:Millenium: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Maciejewski:Novartis: Consultancy; Alexion: Consultancy.

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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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Increased Early Mortality after Fludarabine and Melphalan Conditioning with Peripheral Blood Grafts in Haploidentical SCT with Post-Transplant Cyclophosphamide

Blood ◽

10.1182/blood-2019-129872 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4496-4496 ◽

Cited By ~ 1

Author(s):

Luke Eastburg ◽

David A. Russler-Germain ◽

Ramzi Abboud ◽

Peter Westervelt ◽

John F. DiPersio ◽

...

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

T Cell ◽

Board Of Directors ◽

Research Funding ◽

Early Mortality ◽

Cell Transplant ◽

Advisory Committees ◽

Post Transplant ◽

Equity Ownership

The use of post-transplant cyclophosphamide (PTCy) in the context of haploidentical stem cell transplant (haplo-SCT) has led to drastically reduced rates of Graft-vs-Host (GvH) disease through selective depletion of highly allo-reactive donor T-cells. Early trials utilized a reduced-intensity Flu/Cy/TBI preparative regimen and bone marrow grafts; however, relapse rates remained relatively high (Luznik et al. BBMT. 2008). This led to the increased use of myeloablative (MA) regimens for haplo-SCT, which have been associated with decreased relapse rates (Bashey et al. J Clin Oncol. 2013). Most studies have used a MA total body irradiation (TBI) based regimen for haplo-SCT. Preparative regimens using fludarabine and melphalan (FluMel), with or without thiotepa, ATG, and/or low dose TBI have also been reported using bone marrow grafts. Reports on the safety and toxicity of FluMel in the haplo-SCT setting with PTCy and peripheral blood stem cell (PBSC) grafts are lacking. In this two-center retrospective analysis, the safety/toxicity of FluMel as conditioning for haplo-SCT was evaluated. We report increased early mortality and toxicity using standard FluMel conditioning and PBSC grafts for patients undergoing haplo-SCT with PTCy. 38 patients at the University of Rochester Medical Center and the Washington University School of Medicine underwent haplo-SCT with FluMel conditioning and PBSC grafts between 2015-2019. Outcomes were measured by retrospective chart review through July 2019. 34 patients (89.5%) received FluMel(140 mg/m2). Two patients received FluMel(100 mg/m2) and two patients received FluMel(140 mg/m2) + ATG. The median age at time of haplo-SCT was 60 years (range 21-73). 20 patients were transplanted for AML, eight for MDS, two for PMF, two for NHL, and five for other malignancies. The median Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI) score was 4 (≥3 indicates high risk). 11 patients had a history of prior stem cell transplant, and 16 patients had active disease prior to their haplo-SCT. Seven patients had sex mismatch with their stem cell donor. Median donor age was 42 (range 21-71). 20 patient deaths occurred by July 2019 with a median follow up of 244 days for surviving patients. Nine patients died before day +100 (D100, "early mortality"), with a D100 non-relapse mortality (NRM) rate of 24%. Median overall and relapse free survival (OS and RFS, respectively) were 197 days (95% CI 142-not reached) and 180 days (95% CI 141-not reached), respectively, for the entire cohort. The 1 year OS and NRM were 29% and 50%. The incidence of grades 2-4cytokine release syndrome (CRS) was 66%, and 52% of these patients were treated with tocilizumab. CRS was strongly associated with early mortality, with D100 NRM of 36% in patients with grade 2-4 CRS compared to 0% in those with grade 0-1. The incidence of acute kidney injury (AKI) was 64% in patients with grade 2-4 CRS, and 8% in those without (p < 0.001). 28% of patients with AKI required dialysis. Grade 2-4 CRS was seen in 54% of patients in remission prior to haplo-SCT and in 92% of those with active disease (p = 0.02). Of the 9 patients with early mortality, 89% had AKI, 44% needed dialysis, and 100% had grade 2-4 CRS, compared to 31%, 10%, and 55% in those without early mortality (p = 0.002, p = 0.02, p = 0.01). Early mortality was not significantly associated with age, HCT-CI score, second transplant, disease status at transplant, total dose of melphalan, volume overload/diuretic use, or post-transplant infection. In conclusion, we observed a very high rate of NRM with FluMel conditioning and PBSC grafts for haplo-SCT with PTCy. The pattern of toxicity was strongly associated with grade 2-4 CRS, AKI, and need for dialysis. These complications may be mediated by excessive inflammation in the context of allo-reactive donor T-cell over-activation. Consistent with this, multiple groups have shown that FluMel conditioning in haplo-SCT is safe when using bone marrow or T-cell depleted grafts. Based on our institutional experiences, we would discourage the use of FluMel as conditioning for haplo-SCT with PTCy with T-cell replete PBSC grafts. Alternative regimens or variations on melphalan-based regimens, such as fractionated melphalan dosing or inclusion of TBI may improve outcomes but further study and randomized controlled trials are needed. This study is limited in its retrospective design and sample size. Figure Disclosures DiPersio: WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Karyopharm Therapeutics: Consultancy; Magenta Therapeutics: Equity Ownership; Celgene: Consultancy; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; NeoImmune Tech: Research Funding; Amphivena Therapeutics: Consultancy, Research Funding; Bioline Rx: Research Funding, Speakers Bureau; Macrogenics: Research Funding, Speakers Bureau; Incyte: Consultancy, Research Funding; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees. Liesveld:Onconova: Other: Data safety monitoring board; Abbvie: Membership on an entity's Board of Directors or advisory committees.

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Phase II Trial of the Combination of Ixazomib, Lenalidomide, and Dexamethasone in High-Risk Smoldering Multiple Myeloma

Blood ◽

10.1182/blood-2018-99-117871 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 804-804 ◽

Cited By ~ 7

Author(s):

Mark Bustoros ◽

Chia-jen Liu ◽

Kaitlen Reyes ◽

Kalvis Hornburg ◽

Kathleen Guimond ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

High Risk ◽

Disease Progression ◽

Board Of Directors ◽

Rna Sequencing ◽

Research Funding ◽

Response Rate ◽

Advisory Committees ◽

Equity Ownership

Abstract Background. This study aimed to determine the progression-free survival and response rate using early therapeutic intervention in patients with high-risk smoldering multiple myeloma (SMM) using the combination of ixazomib, lenalidomide, and dexamethasone. Methods. Patients enrolled on study met eligibility for high-risk SMM based on the newly defined criteria proposed by Rajkumar et al., Blood 2014. The treatment plan was designed to be administered on an outpatient basis where patients receive 9 cycles of induction therapy of ixazomib (4mg) at days 1, 8, and 15, in combination with lenalidomide (25mg) at days 1-21 and Dexamethasone at days 1, 8, 15, and 22. This induction phase is followed by ixazomib (4mg) and lenalidomide (15mg) maintenance for another 15 cycles. A treatment cycle is defined as 28 consecutive days, and therapy is administered for a total of 24 cycles total. Bone marrow samples from all patients were obtained before starting therapy for baseline assessment, whole exome sequencing (WES), and RNA sequencing of plasma and bone marrow microenvironment cells. Moreover, blood samples were obtained at screening and before each cycle to isolate cell-free DNA (cfDNA) and circulating tumor cells (CTCs). Stem cell collection is planned for all eligible patients. Results. In total, 26 of the planned 56 patients were enrolled in this study from February 2017 to April 2018. The median age of the patients enrolled was 63 years (range, 41 to 73) with 12 males (46.2%). Interphase fluorescence in situ hybridization (iFISH) was successful in 18 patients. High-risk cytogenetics (defined as the presence of t(4;14), 17p deletion, and 1q gain) were found in 11 patients (61.1%). The median number of cycles completed was 8 cycles (3-15). The most common toxicities were fatigue (69.6%), followed by rash (56.5%), and neutropenia (56.5%). The most common grade 3 adverse events were hypophosphatemia (13%), leukopenia (13%), and neutropenia (8.7%). One patient had grade 4 neutropenia during treatment. Additionally, grade 4 hyperglycemia occurred in another patient. As of this abstract date, the overall response rate (partial response or better) in participants who had at least 3 cycles of treatment was 89% (23/26), with 5 Complete Responses (CR, 19.2%), 9 very good partial responses (VGPR, 34.6%), 9 partial responses (34.6%), and 3 Minimal Responses (MR, 11.5%). None of the patients have shown progression to overt MM to date. Correlative studies including WES of plasma cells and single-cell RNA sequencing of the bone microenvironment cells are ongoing to identify the genomic and transcriptomic predictors for the differential response to therapy as well as for disease evolution. Furthermore, we are analyzing the cfDNA and CTCs of the patients at different time points to investigate their use in monitoring minimal residual disease and disease progression. Conclusion. The combination of ixazomib, lenalidomide, and dexamethasone is an effective and well-tolerated intervention in high-risk smoldering myeloma. The high response rate, convenient schedule with minimal toxicity observed to date are promising in this patient population at high risk of progression to symptomatic disease. Further studies and longer follow up for disease progression are warranted. Disclosures Bustoros: Dava Oncology: Honoraria. Munshi:OncoPep: Other: Board of director. Anderson:C4 Therapeutics: Equity Ownership; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Takeda Millennium: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Oncopep: Equity Ownership. Richardson:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ghobrial:Celgene: Consultancy; Takeda: Consultancy; Janssen: Consultancy; BMS: Consultancy.

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EZH2 Mutations and Impact on Clinical Outcome Analyzed in 1604 Patients with Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-114421 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1528-1528

Author(s):

Sebastian Stasik ◽

Jan Moritz Middeke ◽

Michael Kramer ◽

Christoph Rollig ◽

Alwin Krämer ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Mutational Status ◽

Equity Ownership ◽

Acute Myeloid

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.

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Genomic and Transcriptomic Differences of Myelodysplastic Syndrome/Myeloproliferative Neoplasm with Ring Sideroblasts and Thrombocytosis (MDS/MPN-RS-T) and Myelodysplastic Syndrome with Ring Sideroblasts (MDS-RS)

Blood ◽

10.1182/blood-2020-139983 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 18-19

Author(s):

Guillermo Montalban Bravo ◽

Rashmi Kanagal-Shamanna ◽

Faezeh Darbaniyan ◽

Irene Ganan-Gomez ◽

Koji Sasaki ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Research Funding ◽

Myeloproliferative Neoplasm ◽

Enrichment Analysis ◽

Cytokine Signaling ◽

Healthy Controls ◽

Kinase Signaling ◽

Advisory Committees ◽

Ring Sideroblasts

INTRODUCTION: Myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is a rare hematological disorder characterized by anemia, bone marrow dysplasia with ring sideroblasts and persistent thrombocytosis, and high frequency of SF3B1 and JAK2 mutations. Despite clinical, histological and molecular similarities with MDS with ring sideroblasts (MDS-RS), the clinical outcomes of these entities are diverse. To date, there is no data evaluating specific functional pathways which might explain phenotypic and clinical differences beyond diverse frequencies of JAK2 mutation. METHODS: We evaluated a total of 24 patients (pts) with MDS/MPN-RS-T and 27 pts with MDS-RS. Diagnosis was based on WHO 2017 criteria and confirmed by two independent hematopathologists. Whole bone marrow DNA was subject to 81 gene targeted next-generation sequencing (NGS) analysis. CD34+ cells from bone marrow samples of 4 pts with MDS/MPN-RS-T, 7 pts with MDS-RS and 17 healthy individuals obtained from AllCells (Emeryville, CA) were isolated using the CD34 MicroBead Kit and RNA was isolated using the PicoPure RNA isolation kit. Fastq files were mapped to the human genome (build GRCh38) in TopHat2 using the default options. Differential gene expression analysis was conducted using DESeq2 in R version 3.6.2. Pathway enrichment analysis was performed using gene set enrichment analysis, with the fgsea library in R. RESULTS: Patients with MDS/MPN-RS-T had higher median bone marrow ring sideroblast percentage (47% vs 32%, p=0.04) and absolute neutrophil count (4.34x109/L vs 2.99x109/L, p=0.001). Frequency of identified mutations and their VAFs compared to MDS-RS are shown in Figure 1A. The median number of mutations was higher in MDS/MPN-RS-T than in MDS-RS (3 vs 2, p<0.001). SF3B1 mutations were the most frequent in both entities (MDS/MPN-RS-T: 92%, MDS-RS: 82%), had similar median VAF (34% vs 32%, p=0.619), and involved the hot spot codon K700E in 64% and 43% of MDS-RS and MDS/MPN-RS-T (p=0.227), respectively. As expected, 58% of pts with MDS/MPN-RS-T had JAK2 V617F mutations but were also more likely to have mutations in kinase signaling genes (NF1, SETBP1, CBL, CBLB, FLT3 TKD, MPL) compared to MDS-RS (29% vs 4%, p=0.019). Four (40%) of JAK2 negative MDS/MPN-RS-T had mutations in kinase signaling genes. There were no differences in frequency of TET2 mutations between both entities. However, there was a trend for the median VAF of TET2 mutations in MDS/MPN-RS-T to be lower than in MDS-RS (1.5% vs 21.1%, p=0.177) suggesting a likely subclonal nature of these mutations compared to MDS-RS in which they appeared as dominant events. MDS/MPN-RS-T showed distinct transcriptomic profile compared to both healthy controls and MDS-RS. Compared to healthy controls, a total of 2 pathways were significantly upregulated and 58 were downregulated in MDS/MPN-RS-T while 5 pathways were upregulated and 69 were downregulated in MDS-RS. Compared to MDS-RS, a total of 29 pathways were significantly upregulated and 26 were downregulated in MDS/MPN-RS-T. The most significantly upregulated pathways in MDS/MPN-RS-T included genes involved in platelet activation and aggregation, cytokine signaling, and signaling through GPC receptors (Figure 1C). Compared to both healthy control and MDS-RS, MDS/MPN-RS-T was characterized by downregulation of genes involved in DNA damage response, regulation of apoptosis, telomere maintenance and RNA synthesis (Figure 1D). MDS-RS was characterized by downregulation of genes involved in signaling by GPC receptors and MAPK signaling, mRNA splicing, cytokine signaling and signaling through interleukins compared to both control and MDS/MPN-RS-T (Figure 1C). CONCLUSIONS: MDS/MPN-RS-T is characterized by co-dominance of SF3B1 and JAK2 mutations and presence of minor kinase signaling mutations not observed in MDS-RS. Upregulation of cytokine and interleukin signaling mediated through GPC receptors, and downregulation of genes involved in apoptosis and DNA damage are unique transcriptomic features of MDS/MPN-RS-T likely driven by genotype. These unique genomic and transcriptomic characteristics of MDS/MPN-RS-T supports the classification of MDS/MPN-RS-T based on genomic features beyond presence of SF3B1 mutation, and might represent potential therapeutic avenues for this rare disease. Figure Disclosures Sasaki: Otsuka: Honoraria; Pfizer Japan: Consultancy; Novartis: Consultancy, Research Funding; Daiichi Sankyo: Consultancy. Kantarjian:Sanofi: Research Funding; Abbvie: Honoraria, Research Funding; Janssen: Honoraria; BMS: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive biotechnologies: Honoraria; Aptitute Health: Honoraria; Immunogen: Research Funding; Jazz: Research Funding; Daiichi-Sankyo: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; BioAscend: Honoraria; Novartis: Honoraria, Research Funding; Delta Fly: Honoraria; Pfizer: Honoraria, Research Funding; Oxford Biomedical: Honoraria; Ascentage: Research Funding. Garcia-Manero:Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amphivena Therapeutics: Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding; Onconova: Research Funding; Merck: Research Funding; Novartis: Research Funding; H3 Biomedicine: Research Funding; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy.

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Acute Myeloid Leukemia (AML) Treated with Azacitidine: Survival Outcomes for Patients Who Complete More Than Six Cycles Are Similar to High-Risk Myelodysplastic Syndrome/Low Blast Count AML

Blood ◽

10.1182/blood-2019-122122 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5156-5156

Author(s):

Jill Fulcher ◽

Zahra Abdrabalamir Alshammasi ◽

Nathan Cantor ◽

Christopher Bredeson ◽

Grace Christou ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Median Survival ◽

Research Funding ◽

Survival Outcomes ◽

Advisory Committees ◽

Ottawa Hospital ◽

Funding Agencies ◽

Progression Of Disease ◽

Refractory Aml

INTRODUCTION: Despite accumulating evidence supporting the efficacy of hypomethylating agents in patients with AML and > 30% bone marrow blasts as well as in relapsed/refractory AML, this therapy is not yet funded by National Health Plans / Healthcare Funding Agencies in a number of countries including Canada. The assistance of an industry-sponsored compassionate program has enabled provision of azacitidine for this group of patients at The Ottawa Hospital. We report here our local "real-world" experience of azacitidine efficacy in this diverse group of AML patients and identify a sub-group whose outcomes are equivalent to that of patients with higher-risk Myelodysplastic Syndrome (MDS) and AML with 20-30% blasts for whom azacitidine therapy has funding approval in Canada. METHODS: All patients who received azacitidine at The Ottawa Hospital between 2009 and 2016 were included in this single-center, retrospective analysis. Azacitidine was administered at a dose of 75mg/m2 subcutaneously daily for 7 consecutive days every 28 days. Response was evaluated with a repeat bone marrow aspirate and trephine biopsy after the 6th cycle. In those patients confirmed to have stable or responsive disease, azacitidine was continued until progression of disease, intolerable side-effects of the drug or the patient chose to discontinue therapy. Overall survival curves were generated using the Kaplan-Meier method and log-rank tests were used to compare subgroups of patients. Actuarial median survival months were calculated with 95% confidence intervals (CI). P-values less than 0.05 were considered statistically significant. RESULTS: During the study period, 109 patients received azacitidine: 54 had MDS /AML with 20-30% blasts (the 'funded' group) and 55 had either AML with > 30 % blasts (n=23), AML relapsed post-intensive chemotherapy (n=14), AML relapsed post-allogeneic stem cell transplant (n=10) or primary refractory AML (n=8) (the 'unfunded' group). Median survival of the 'funded' group was 12.2 months while median survival of the 'unfunded' group was 5.6 months (95% CI 3.3-7.7; p=0.0058). Of the AML patients in the 'unfunded' group, 24% completed more than 6 cycles of azacitidine compared to 52% of patients in the 'funded' group. In both the 'funded' and 'unfunded' groups, patients who completed more than 6 cycles of azacitidine had similar survival outcomes (p=0.7277): the 'funded' group had a median survival of 19 months (95% CI 14.4-25.3) while the median survival of this sub-population of the 'unfunded' AML group was 22 months (95% CI 11.7-24.9). Patients in both groups who failed to complete more than 6 cycles of azacitidine also had a similar outcome (p=0.39), with a median survival of 5.7 months (95% CI 4.0-6.3) for patients with MDS/AML 20-30% blasts and 3.6 months (95% CI 2.2-5.1) for AML patients with > 30% blasts or relapsed/refractory disease. Reasons for patients not completing at least 6 cycles of azacitidine included progression of disease (25%), bacterial infections most commonly pneumonia (53%) and patient preference (7%). CONCLUSION: A significant sub-population of AML patients with > 30% blasts or refractory/relapsed AML can achieve a meaningful survival benefit with the hypomethylating agent, azacitidine. A higher proportion of this AML patient population discontinued azacitidine as a result of infective complications. The provision of routine prophylactic antibiotics may enable more patients with AML to receive an adequate amount of azacitidine to achieve therapeutic benefit and warrants further investigation. Our results add to the growing body of 'real-world' evidence that supports healthcare funding agencies to provide coverage of azacitidine for patients with AML who in some countries at present do not fulfill government funding criteria. Disclosures Bredeson: Otsuka: Research Funding. Maze:Pfizer Inc: Consultancy; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Sabloff:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; ASTX: Membership on an entity's Board of Directors or advisory committees, Research Funding; Actinium Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas Pharma Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi Canada: Research Funding.

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Correlation of Hemophagocytosis with Clinical Criteria of Hemophagocytic Lymphohistiocytosis and Recommendations for Screening Bone Marrow Samples in Adult Patients

Blood ◽

10.1182/blood-2020-139246 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 37-38

Author(s):

Caroline Wilson ◽

Wei-i Lee ◽

Matthew Cook ◽

Lillian Smyth ◽

Dipti Talaulikar

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Hemophagocytic Lymphohistiocytosis ◽

Research Funding ◽

Interobserver Variability ◽

Laboratory Data ◽

Adult Patients ◽

Advisory Committees ◽

Bone Marrow Biopsies ◽

Immunohistochemical Stain

Introduction Hemophagocytic lymphohistiocytosis (HLH) is a rare condition resulting from a dysregulated inflammatory response. It can prove difficult to diagnose and portends a poor prognosis. Bone marrow (BM) biopsy is an easily accessible test that is often used to identify the presence of hemophagocytosis and assess for underlying malignancy. Currently there are no evidence-based guidelines on the reporting of hemophagocytosis on BM biopsy and no reports of a correlation between hemophagocytosis with the clinical diagnostic criteria for HLH. We therefore aimed to assess if the amount of hemophagocytosis identified in the BM biopsy correlates with HLH-2004 criteria. Secondary aims were to evaluate inter-observer variability in reporting hemophagocytosis, and to formulate recommendations for screening in BM specimens. Method A retrospective review of bone marrow biopsies from adult patients under investigation for HLH was undertaken independently by 2 hematopathologists who were blinded to the original biopsy report. Relevant clinical and laboratory data was extracted from medical records. The average number of actively hemophagocytic cells in each slide prepared from BM aspirates were quantified into 0, 1, 2-4 and ≥5. On trephine samples, hemophagocytosis was reported as either 'present' or 'absent', with the assistance of the CD68 immunohistochemical stain. Cases with discordance pertaining to the degree of hemophagocytosis were reviewed by both assessors to reach a consensus. Results Sixty-two specimens from 59 patients were available for assessment. An underlying hematological condition was identified in 34 cases (58%). The most common underlying hematological condition was lymphoma, found in 15 cases (25%). There was a significant association between the amount of hemophagocytosis identified on the aspirate samples and the number of HLH-2004 criteria met (p<0.05). In patients where hemophagocytosis was present (n=31), there was a significant correlation between the amount of hemophagocytosis and ferritin levels (p<0.05). Interobserver variability was present in 63% of cases. Based on our review, we make the following recommendations for reporting of hemophagocytosis in the BM samples:> 1. Count only macrophages ingesting intact hemopoietic cells. W2. Quantify the average number of active histiocytes per aspirate slide. W3. Count histiocytes away from particles where the cellular outline is clear. W4. Avoid counting conglomerates of histiocytes where the cellular margins are indistinct W5. On the aspirate specimen, assess for hemophagocytosis on both the trail and squash preparations. W6. Delineating hemophagocytosis on trephine samples is difficult without the use of a CD68 immunohistochemical stain. Interestingly, a study by Ho et al found no association between the BM histologic findings and the probability of hemophagocytosis (Ho et al, American Journal of Clinical Pathology, 2014). This difference highlights the need for standardised reporting of BM specimens. Conclusion Our findings indicate that the amount of hemophagocytosis present on BM samples correlates with the number of HLH-2004 criteria met. We found marked interobserver variability which we anticipate can be rectified with our recommendations on the reporting of hemophagocytosis. Disclosures Talaulikar: Takeda: Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Inhibition of the Proteasome in Bone Marrow-Derived CD138+ Tumor Cells Following Carfilzomib Administration in Relapsed or Refractory Myeloma Patients.

Blood ◽

10.1182/blood.v114.22.1845.1845 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1845-1845

Author(s):

Suzanne Trudel ◽

Susan Lee ◽

Christopher J. Kirk ◽

Nashat Gabrail ◽

Sagar Lonial ◽

...

Keyword(s):

Bone Marrow ◽

Board Of Directors ◽

Tumor Cells ◽

Whole Blood ◽

Research Funding ◽

Proteasome Inhibition ◽

Proteasome Activity ◽

Advisory Committees ◽

Post Dose ◽

Blood Samples

Abstract Abstract 1845 Poster Board I-871 Background: Proteasome inhibition is an effective strategy for the treatment of multiple myeloma. In patients, proteasome inhibition has primarily been measured in peripheral blood samples (whole blood or mononuclear cells). However, it is unknown whether myeloma cells in the bone marrow (BM) are equally sensitive to proteasome inhibitors such as bortezomib (BTZ) and carfilzomib (CFZ). Aim: To measure proteasome inhibition in purified tumor cells from BM samples taken from patients enrolled in two ongoing Phase 2 trials of single agent CFZ in relapsed or refractory myeloma: PX-171-003 (003) and PX-171-004 (004). Methods: CFZ was administered as an IV bolus of 20 mg/m2 on Days 1, 2, 8, 9, 15 and 16 of a 28-day cycle on both trials. Bone marrow samples, from an optional sub-study of both trials, were taken during screening and Day 2 (post-treatment) and sorted into CD138+ and CD138− cells. Proteasome activity was measured by an enzymatic assay using a fluorogenic substrate (LLVY-AMC) for the chymotrypsin-like (CT-L) activity and an active site ELISA (ProCISE) to quantitate levels of the CT-L subunits of the constitutive proteasome (Beta5) and immunoproteasome (LMP7) and the immunoproteasome subunit MECL1. Results: Whole blood samples from patients treated with CFZ showed inhibition of CT-L activity of ∼80+, similar to values obtained in Phase 1 studies. A total of 10 CD138+ screening samples, 6 from 004 and 4 from 003, and 9 post-dose samples, 5 from 004 and 4 from 003, were analyzed for proteasome levels and activity. In addition, 15 CD138−screening samples, 7 from 004 and 8 from 003, and 9 post-dose samples, 5 from 004 and 4 from 003, were analyzed. When compared to the average base-line activity, CFZ treatment resulted in 88% CT-L inhibition in CD-138+tumor cells from 004 patients (P = 0.0212 by unpaired t-test) and 59% CT-L inhibition in CD-138+ tumor cells from 003 patients (P = 0.25). Baseline CT-L activity in CD138+ tumor cells was 3-fold higher in 004 than 003, which includes a more heavily pre-treated patient population with greater prior exposure to BTZ. Higher specific enzymatic activity was due to increased levels of both constitutive and immunoproteasomes in tumor cells, where immunoproteasomes account for >75% of total cellular proteasomes. No differences between trials were seen in baseline CT-L activity from non-tumor (CD138−) cells. Inhibition in CD138− cells was 84% (P = 0.0380 and 42% (P = 0.38) in 004 and 003, respectively. Using ProCISE, we measured inhibition of LMP7 (66%), beta5 (48%) and MECL1 (64%) in CD138+ tumor cells from 004 patients. Three patients from 004 and one from 003 had both a screening and post-dose tumor cell samples available for analysis. Inhibition of CT-L activity was >80% in two of the 3 patients on 004; the third patient showed no proteasome inhibition by ProCISE and was unavailable for analysis by CT-L. CT-L activity in the CD138+ tumor cells in the 003 patient was not inhibited, however, inhibition was seen in non-tumor cells. Conclusions: CFZ inhibits the proteasome activity of myeloma cells in the bone marrow of relapsed and refractory myeloma patients. The levels of inhibition were similar to those measured in whole blood samples, supporting the use of the blood-based assay as a surrogate marker for proteasome inhibition in tumor cells. CFZ treatment resulted in inhibition of both CT-L subunits as well as additional subunits of the immunoproteasome in tumor cells. Reduced baseline activity in the more heavily pretreated 003 patients may reflect reduced tumor-dependency on the proteasome and may be related to prior treatment with BTZ in these patients. More samples are needed in order to make correlations between levels of proteasome inhibition in bone marrow tumor cells and prior therapies or response. These observations support further evaluation of proteasome activity and the effects of this promising new agent in primary tumors cells from myeloma patients. Disclosures: Trudel: Celgene: Honoraria, Speakers Bureau; Ortho Biotech: Honoraria. Lee:Proteolix, Inc.: Employment. Kirk:Proteolix, Inc.: Employment. Lonial:Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding. Wang:Proteolix, Inc.: Research Funding. Kukreti:Celgene: Honoraria. Stewart:Genzyme, Celgene, Millenium, Proteolix: Honoraria; Takeda, Millenium: Research Funding; Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy. Jagannath:Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. McDonagh:Proteolix: Research Funding. Zonder:Celgene: Speakers Bureau; Pfizer: Consultancy; Seattle Genetics, Inc.: Research Funding; Amgen: Consultancy; Millennium: Research Funding. Bennett:Proteolix: Employment.

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