bluuebunny/crossref_metadata_2025 huggingface dataset:
Very Long-Term Follow-up Results of Imatinib Mesylate Therapy in Chronic Phase Chronic Myeloid Leukemia After Failure of Interferon Alpha Therapy
Authors: Alattar Mona Lisa , Cortes Jorge E. , O'Brien Susan , Garcia-Manero Guillermo , Faderl Stefan , Ravandi Farhad , Jabbour Elias , Shan Jianqin , Kantarjian Hagop M.
Published: October 2019

Abstract 2749

Background:

The long-term outcome of patients with chronic phase chronic myeloid leukemia treated with imatinib after failure of interferon alpha therapy has not been detailed. Patients and Methods: 368 patients were analyzed. Univariate and multivariate analyses for survival were conducted using standard statistical methods. Results: Overall, 247 patients (67%) achieved complete cytogenetic response (CCyR). Of 327 patients studied, 207(63%) achieved major molecular response (MMR), and 99 (30%) had undetectable BCR-ABL levels at some time on therapy. The estimated 10-year survival rate was 68%, progression-free survival rate 67%, and event-free survival rate 51%. By multivariate analysis, age ≥ 60 years, hemoglobin < 10g/dl, marrow basophils ≥ 5%, any peripheral blasts, and clonal evolution were independent adverse factors for survival. The estimated 7-year survival by the presence of none (n=154), 1–2 (n=190), or ≥ 3 factors (n=24) were 93%, 70%, and 25% respectively (p <0.01). Achievement of MMR, CCyR, or partial cytogenetic response at 12 months were associated with significantly better 10-year survival rate by landmark analysis (10-year survival 80–90%) vs. achieving minor cytogenetic response or complete hematologic response (10-year survival 55–65%) vs. other response (10-year survival 10%). Using landmark analysis to include imatinib response at 12 months, achievement of major cytogenetic response or better (hazard ratio 0.12; p< 0.001) and complete hematologic response or minor cytogenetic response (hazard ratio 0.36; p=0.003) were significant favorable prognostic factors. Conclusions: The estimated 10-year survival rate of 68% in patients with chronic myeloid leukemia receiving imatinib after interferon failure has improved.

Disclosures:

Cortes: Novartis: Consultancy; Novartis: Research Funding; BMS: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Kantarjian:Novartis: Consultancy; Novartis: Research Funding; Pfizer: Research Funding; BMS: Research Funding.
Evaluation of a New Nanoparticle-Based Lateral-Flow Immunoassay for the Exclusion of Heparin-Induced Thrombocytopenia (HIT),
Authors: Sachs Ulrich J. , von Hesberg Jakob , Santoso Sentot , Bein Gregor , Bakchoul Tamam
Published: October 2019

Abstract 3290

Background:

Heparin-induced thrombocytopenia (HIT) is an adverse complication of heparin caused by HIT antibodies (abs) that recognize platelet factor 4-heparin (PF4/hep) complexes. Several laboratory tests are available for the confirmation and/or refutation of HIT. A reliable and rapid single-sample test is still pending. Objectives: To evaluate a new lateral-flow immunoassay based on nanoparticle technology. Patients/methods: A cohort of 452 surgical and medical patients suspected of having HIT was evaluated. All samples were tested in two IgG-specific ELISAs, in a particle gel immunoassay (PaGIA) and in a newly developed lateral-flow immunoassay (LFI-HIT) as well as in a functional test (HIPA). Clinical pre-test probability was determined using 4T's score. Results: Platelet-activating antibodies were present in 34/452 patients, all of whom had intermediate to high clinical probability. PF4/hep abs were detected in 79, 87, 86, and 63 sera using the four different immunoassays. The negative predictive values (NPV) were 100% for both ELISA tests and LFI-HIT but only 99.2% for PaGIA. There were less false positives (n=29) in the LFI-HIT compared to any other test. Additionally, significantly less time was required to perform LFI-HIT (median time, 11 min 30 sec) than to perform the other immunoassays. Conclusion: A newly developed lateral-flow assay, LFI-HIT, was capable of identifying all HIT patients in a cohort in a short period of time. Beside an NPV of 100%, the rate of false-positive signals is significantly lower with LFI-HIT than with other immunoassay(s). These performance characteristics suggest a high potency in reducing the risk and costs in patients suspected of having HIT.

Disclosures:

No relevant conflicts of interest to declare.
Increased Heparanase Level and Procoagulant Activity in Orthopedic Surgery Patients Receiving Prophylactic Dose of Enoxaparin,
Authors: Peled Eli , Robitzki Alexie , Axelman Elena , Norman Doron , Brenner Benjamin , Nadir Yona
Published: October 2019

Abstract 3333

Background:

Orthopedic hip and knee surgeries are followed by a hypercoagulable state. Heparanase is implicated in inflammation, coagulation activation and angiogenesis. Recently, heparanase was shown to directly interact with tissue factor (TF) and to enhance generation of factor Xa (Nadir et al, Haematologica, 2010). In addition, an assay evaluating heparanase procoagulant activity has been lately developed (Nadir et al, Thromb Res, 2011). In the present study, heparanase level and procoagulant activity in patients undergoing orthopedic surgery were assessed. Methods: The study group included 50 orthopedic patients. Thirty one patients underwent hip operation and 19 had knee surgery. Fifteen individuals suffered from traumatic hip fractures and 35 had osteoarthrosis of hip or knee joints. All patients received a prophylactic dose of enoxaparin starting 6–8 hours post operation and lasting for 5 weeks. Plasma samples were drawn preoperatively and at 1 hour, 1 week and 1 month post surgery. Samples were tested for heparanase levels by ELISA and TF/heparanase complex activity, TF activity, heparanase procoagulant activity, factor Xa and thrombin levels were estimated using chromogenic substrates. Results: Heparanase levels were significantly higher 1 hour and 1 week postoperatively compared to preoperative levels (p<0.05, p<0.005, respectively). The most dramatic changes were observed in heparanase procoagulant activity, reaching a 2-fold increase 1 week postoperatively and a 1.7-fold increase 1 month after surgery (p<0.0001 and p<0.0001, respectively). Levels of factor Xa and thrombin did not significantly change. Conclusions: Heparanase is found to be involved in coagulation activation of orthopedic surgery patients, with heparanase procoagulant activity being highest 1 week postoperatively and still remaining high 1 month after operation. Consideration of extending prophylactic anticoagulant therapy or evaluation of heparanase procoagulant activity may potentially prevent late thrombotic events in this patient population.

Disclosures:

No relevant conflicts of interest to declare.
Stress-Induced Activation of Dormant Hematopoietic Stem Cells In Vivo,
Authors: Essers Marieke , Lutz Raphael , Thamm Stefanie , Uckelmann Hannah , Wurzer Stephan , Trumpp Andreas
Published: October 2019

Abstract 3390

Maintenance of the blood system is dependent on dormant haematopoietic stem cells (HSCs), which are characterized by pluripotency and life long self-renewal capacity. In order to both maintain a supply of mature blood cells and not exhaust HSCs throughout the lifespan of the organism, most adult HSCs remain quiescent and only a limited number are cycling at any given time. The balance between self-renewal and differentiation of HSCs is controlled by external factors such as chemokines, as well as interactions of HSCs with its niche environment.

We have recently shown that the cytokine IFNa very efficiently activates dormant HSCs in vivo. Within hours after treatment of mice with IFNa HSCs exit G0 and enter the active cell cycle. In general, IFNa is produced in response to viral infections by cells of the immune system, and plays an important role in the host defense against the viral infection. We now questioned whether endogenous IFNa is also produced in response to other forms of bone marrow stress and whether this affects the proliferation rate of HSCs. To monitor IFNa production in the bone marrow in vivo, we have generated MxCre; ROSA-R26-EYFP mice and found that treatment with both the chemotherapeutic agent 5-FU as well as the endotoxin LPS leads to the production of IFNa in HSCs and progenitors. In addition, LPS treatment in vivo induced a strong increase in proliferation of HSCs. In contrast to the direct effect of IFNa on HSCs, in vivo and in vitro experiments have shown that the LPS induced activation of HSCs is triggered via an indirect effect of LPS on CD11b+ cells in the bone marrow. Activation of these cells via TLR4 signaling then results in increased proliferation of the HSCs, a mechanism we are currently investigating in more detail.

Interestingly, LPS induced activation correlated with increased expression of Sca-1 on HSCs, similar to the increased Sca-1 expression upon IFNa treatment. As for IFNa, the upregulation of Sca-1 is required for LPS induced proliferation, since Sca-1−/− mice do not respond to LPS stimulation. Furthermore, cDNA array comparisons between HSCs treated with IFNa or LPS suggest a more common mechanism of activation, independent of the source leading to the activation.

In summary, these data suggest that in addition to viral infection also other forms of bone marrow stress, like LPS, result in activation of quiescent HSCs in the bone marrow, probably via similar mechanisms. Furthermore, both IFNa and LPS induced activation of HSCs are dependent on the up-regulation of Sca-1, suggesting a more general role for Sca-1 in the activation of stem cells.

Disclosures:

No relevant conflicts of interest to declare.
Core Transcriptional Regulatory Circuit Controlled by the TAL1 Complex in T-Cell Acute Lymphoblastic Leukemia,
Authors: Sanda Takaomi , Lawton Lee N , Barrasa M Inmaculada , Fan Zi Peng , Ahn Yebin , Young Richard , Look A. Thomas
Published: October 2019

Abstract 3453

Aberrant expression of TAL1 is one of the most frequent abnormalities in T-cell acute lymphoblastic leukemia (T-ALL), yet little is known about the transcriptional network controlled by this oncogenic transcription factor, posing a major obstacle to understanding T-ALL pathogenesis. Here we identify the core transcriptional regulatory circuit controlled by TAL1 and its regulatory partners HEB, E2A, GATA3 and RUNX1 in T-ALL cells. We determined direct transcriptional targets of TAL1 and its regulatory partners by ChIP-seq analysis, and found that TAL1 binds to the majority of HEB- and E2A-enriched regions and that these commonly bound regions are frequently overlapping with the GATA3- and RUNX1-enriched regions. We found that TAL1 forms an interconnected auto-regulatory loop with its partners, which likely contribute to the sustained upregulation of its direct target genes. TAL1 core regulatory circuit activates genes involved in T-cell development and hematopoesis. Microarray gene expression analysis revealed that TAL1 and GATA3 predominantly act as positive regulators of the expression of their direct target genes in T-ALL. Importantly, we found the MYB oncogenic transcription factor is directly activated by the TAL1 complex and positively regulates many of the same target genes, thus forming a feed-forward positive regulatory loop that further promotes the TAL1-regulated oncogenic program. Moreover, we found that a specific subset of TAL1 target genes are oppositely regulated by TAL1 and its obligate partner proteins E2A and HEB, uncovering a leukemogenic pattern that previously emerged from studies in murine models. These findings underscore the importance of TAL1 as a critical regulator of an aberrant gene expression program in T-ALL, and indicate how these networks maintain the malignant state in thymocytes.

Disclosures:

No relevant conflicts of interest to declare.
CD64 Expression Is An Independent Adverse Prognostic Factor in Pediatric Acute Myeloid Leukemia Treated with Allogeneic Stem Cell Transplantation,
Authors: Albitar Maher , Alseraihy Amal , Ayas Mouhab , Al-Jefri Abdullah , Al-Ahmari Ali , Belgaumi Asim F , Walter Claudia Ulrike , Nounou Randa , Khalil Salem , Bakshi Nasir , Owaidah Tarek , El-Solh Hassan
Published: October 2019

Abstract 3525

Background:

The Fcγ receptor I alpha chain (CD64) is usually used as a monocytic marker in immunophenotyping acute myeloid leukemia (AML). The clinical relevance of CD64 expression is controversial and has been reported to be associated with good outcome in the adult population in one large study. The prognostic relevance of CD64 in pediatric AML is not known. More importantly, the outcome is not known when patients expressing CD64 on the surface of their blasts are considered for allogeneic hematpoietic stem cell transplantation (HSCT). We investigated whether HSCT can neutralize the adverse effects of CD64 expression in pediatric AML patients.

Methods:

Immunophenotype data of 53 pediatric patients with AML, all treated with allogeneic HSCT, was reviewed. The expression of the CD64 on the blast population as determined by flow cytometry was correlated with clinical data and outcome. The median age of patients was 8 years (range: 8 months–14 years) and included 40 (75%) patients transplanted in first complete remission (CR1). Thirty eight (72%) of all patients had intermediate-risk cytogenetics and the remaining (28%) had adverse-risk cytogenetic abnormalities. Only 6 of the 53 patients (11%) had MLL rearrangement as determined by karyotyping and FISH studies.

Results:

Fifteen (28%) of all studied patients expressed CD64 on the surface of the blasts at diagnosis. Patients with CD64 expression had significantly shorter overall survival (P=0.005) with median survival of approximately 9 months while the median survival in the CD64 negative patients has not been reached. Similarly, CD64 positive patients had significantly shorter event free survival (EFS) (P=0.004). Even when we considered only patients treated with in CR1 who had HSCT, the OS and EFS for the CD64 positive patients were both significantly shorter (P=0.01 and P=0.009, respectively). The median survival was 8.85 months for the CD64 positive patients, while the median has not been reached in the CD64 negative patients. Multivariate analysis including CD64 expression and cytogenetic risk identified CD64 expression as an independent prognostic factor for survival and EFS, while cytogenetic-risk stratification became no longer a predictor.

Conclusion:

Our data suggests that the expression of CD64 in pediatric AML is a significant independent poor prognostic factor in pediatric AML patients when treated with HSCT. Most of the CD64 positive patients die in their first year after HSCT and the management of these patients should be modified to address early death in this group of patients.

Disclosures:

No relevant conflicts of interest to declare.
Phase I Trial of the Oral Poly (ADP-ribose) Polymerase (PARP) Inhibitor Veliparib (ABT-888, V) Combined Wtih Topoecan (T) and Carboplatin (C) for Adults with Relapsed and Refractory Acute Leukemias,
Authors: Pratz Keith W. , Kaufmann Scott H. , Litzow Mark R. , Ji Jiuping , Chen Alice , Rudek Michelle A , Karp Judith E.
Published: October 2019

Abstract 3634

PARP is activated in response to DNA single strand (SS) breaks and is pivotal to the base excisional repair pathway for chemotherapy-damaged DNA. The orally bioavailable PARP inhibitor V delays DNA repair and potentiates the cytotoxicity of multiple classes of chemotherapy drugs including topoisomerase I inhibitors and platinating agents in leukemia cell lines. A previous clinical trial of T+C yielded promising results in adults with refractory acute leukemia at the maximum tolerated dose (MTD) of T 1.6 mg/m2/d + C 150 mg/m2/d by intravenous continuous infusion (IVCI) × 120 hrs. We are conducting a Phase I dose-escalation trial of V given orally twice daily Days 1–8 with T+C given by 120 hr IVCI Days 3–7.

Deaths due to myocardial infarct and splenic infarcts with ascites occurred in one pt each when C 150 mg/m2 was added to V 10 mg BID and T 1.3 mg/m2, resulting in adjustment of the dose escalation schema for C and T.Dose levelVeliparib Oral Daily Days 1–8Topotecan Continuous IV Days 3–7Carboplatin Continuous IV Days 3–7Clinical Responses/#Pts1A10 mg p.o. BID1.0 mg/m2/day—1/3(CRi)1B10 mg p.o. BID1.3 mg/m2/day—1/3(CR)2A10 mg p.o. BID1.3 mg/m2/day150 mg/m2 IV0/42C10 mg p.o. BID1.0 mg/m2 IV120 mg/m2 IV2/6(CRi, PR)2D10 mg p.o BID1.2 mg/m2 IV120 mg/m2 IV1/6(PR)2E10 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CRi)3C20 mg p.o. BID1.0 mg/m2 IV120 mg/m2 IV0/63D20 mg p.o BID1.2 mg/m2 IV120 mg/m2 IV2/6(CR, PR)3E20 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CR)440 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/6(CR, CR)5§80 mg p.o. BID1.2 mg/m2 IV150 mg/m2 IV2/4(CR, CRi)

Of 56 pts treated at doses of V 10–80 mg orally BID Days1–8 and T 1.0–1.2 mg/m2/d + C 120–150 mg/m2/d for 120 hrs IVCI Days 3–7, 25 (45%) have experienced > grade 3 non-hematologic toxicity, 6(11%) have had grade 4 toxicity and 1 (4%) died from sepsis with multi-organ failure. Overall response rate is 27% (8CR, 4 CRi, 3 PR), with 7 in relapsed AML, 7 in refractory AML and 1 refractory ALL. Pharmacokinetic (PK) studies in pt plasma, marrow supernatant, and marrow blasts demonstrated that V is detectable in marrow supernatant and cells, does not accumulate with multiple dose administrations in plasma but does in marrow, and is not altered by T or C administration. Nuclear staining for phosphorylated histone H2AX (γH2AX) demonstrated that V 10 mg BID increased DNA damage by > 2-fold in 11/22 (50%) on Day 1 and 13/18 (72 %) on Day 4 after 24 hrs of T+C. A PAR ELISA demonstrated that V suppresses PAR levels to <50% of pretreatment values in 30/41 (73%) blood and 3/4 patients at V 40mg per day dose level had greater than 80% suppression of PAR. The MTD has not been reached and dose escalation is ongoing.

Disclosures:

No relevant conflicts of interest to declare.
Preliminary Results of An Ongoing Phase I Trial of Oral Belinostat a Novel Histone Deacetylase Inhibitor in Patients with Lymphoid Malignancies,
Authors: Zain Jasmine M. , Foss Francine M. , Diefenbach Catherine S. , Petrylak Daniel , Narwal Ameet , Neylon Ellen , Knoblauch Poul , O'Connor Owen A.
Published: October 2019

Abstract 3710

Background:

Belinostat (Bel) is a pan class I/II histone deacetylase inhibitor with broad preclinical activity. A phase I study of oral Bel in patients (pts) with solid tumors identified a maximum tolerated dose (MTD) of 750 mg orally (PO) daily on days (d) 1–14, of an every 21 day cycle. An allowance for intra-patient dose escalation was permitted as long as the higher dose level was deemed safe and not the maximum administrable dose. The current study was initiated to assess the safety and dosing of Bel in patients with relapsed or refractory Hodgkin and non-Hodgkin Lymphoma. Methods: 3–6 pts per dose cohort were enrolled on study, at the following doses: A 750; B 1000; C 1250; D1500;E 1750; F 2000mg/d. Pts who met eligibility criteria (ANC =; plts =) with evaluable disease were eligible. Definition of dose limiting toxicity (DLT) included: related non-hem grade (gr) 3/4 tox; gr 4 neutropenia > 5 d or with fever > 100.5 °F; gr 4 thrombocytopenia > 7 d.

Results:

28 pts, median age 48 (range 21–82),prior regimens: median 5,5 (range 0–13), (17 had BM transplants, including 5 pts with allogeneic) have been enrolled. Diagnoses include: HD (12 pts), mantle cell lymphoma (MCL;5 pts), other NHL (11 pts). Most frequent adverse events seen in > 50% of patients (regardless of attribution or gr) in 28 pts fully evaluable for toxicity: diarrhea (25 pts), anorexia/decreased appetite (24 pts), fatigue (23 pts), nausea (18 pts), vomiting (18 pts), cough (17 pts) and fever (15 pts). Non-hem gr 3 events included diarrhea in 9 pts (evenly distributed over the co-horts), grade 3 diarrhea at 1500 and 2000 mg dose were among the 4 DLT's. 5 pts with gr 3/4 thrombocytopenia (shift from baseline) were seen in cohort C, D, E. 16 pts are evaluable to date, and include r, 1 CR (duration: 2+cycles)in NHL patient, 1 PR (duration: 8 cycles) in HD patient, and stable disease have been noted in 12 patients (duration: 1–24 cycles, median 1,5). Aside from the 1 CR and 1 PR, tumor shrinkage between 25– 50% was noted in 8 pts.

Conclusions:

Oral Bel can be delivered safely with a d 1–14, q3w schedule in pts with lymphoma at a daily dose higher than what has been established for pts with solid tumors. MTD for lymphoma pts was established at 1500 mg/d 1–14, q3w. The safety profile and early tumor shrinkage noted in both HD, MCL and other NHL warrants continued evaluation of Bel, especially in combination with other active compounds.

Disclosures:

Foss: esai, allos, merck, celgene: Consultancy, Research Funding. Knoblauch:Topotarget: Employment.
Icsbp/Irf8 Cooperates with Tel to Regulate Fas Induced Apoptosis in Myeloid Leukemia.
Authors: Huang Weiqi , Eklund Elizabeth A.
Published: October 2019

Abstract 395

The interferon consensus sequence binding protein (Icsbp) is an interferon regulatory transcription factor (also known as Irf8) which functions as an anti-oncogene for chronic myeloid leukemia (CML) and acute myeloid leukemia (AML). In previous studies we used chromatin immunoprecipitation based high through put screening approaches to identify Icsbp target genes which explain these effects. The identified set of target genes was enriched for genes encoding proteins which regulate cytokine induced proliferation, beta catenin activity, and Fas induced apoptosis. In further investigations of the latter category, we found that Icsbp represses transcription of PTPN13; the gene encoding Fas associated phosphatase 1 (Fap1). Fap1 binds directly to the C-terminus of Fas, resulting in Fas-dephosphorylation and antagonizing Fas-induced apoptosis. We found that repression of PTPN13 by Icsbp increased during myelopoiesis, resulting in decreased Fap1 expression and increased sensitivity to Fas-induced apoptosis as differentiation proceeds. In the current studies, we investigated the mechanism for Icsbp induced PTPN13 repression. We identified a multi-protein repression complex which includes Icsbp, the ets protein Tel, and Hdac3 which binds to a PTPN13 cis element in a manner requiring recognition of the binding site by Tel. We found that histone deacetylase activity of Hdac3 was essential for PTPN13 repression by this complex. Tel was first identified due to participation in a leukemia associated chromosomal translocation with the gene encoding the PdgfRβ. This translocation is characteristic of Chronic Myelomonocytic Leukemia (CMMoL) and results in expression of a fusion protein with the protein-protein interaction domain of Tel and the kinase domain of PdgfRβ. Tel/PdgfRβ fusion protein exhibits constitutive tyrosine kinase activity due to autophosphorylation and activation of fusion protein dimers. This results in transduction of proliferative signals in the absence of cytokine. In this work we identify another function for the Tel/PdgfRβ fusion protein which may also contribute to the pathogenesis of leukemia. We find that Tel/PdgfRβ fusion protein interacts with wild type Tel protein in the cell (expressed by the allele not involved in the translocation), consistent with results of previous investigators. More importantly, we find that interaction with Tel/PdgfRβ renders Tel unavailable for binding to the PTPN13 cis element, which prevents assembly of the Tel/Icsbp/Hdac3 repression complex. The net result is increased PTPN13 promoter activity and Fap1 expression in cells expressing Tel/PdgfRβ fusion protein. This increase in Fap1 expression contributes to resistance to Fas-induced apoptosis in these cells. Therefore, our studies identify a previously unrecognized mechanism for apoptosis resistance in CMMoL and a potential target for therapeutic intervention in this myelodysplastic/ myeloproliferative disorder.

Disclosures:

No relevant conflicts of interest to declare.
Non-MTC IGH-CCND1 Breakpoints in Mantle Cell Lymphoma Are Associated with CpG Sites and AID Hotspots
Authors: Greisman Harvey A , Lu Zhengfei , Tsai Albert G , Greiner Timothy C. , Yi Hye Son , Lieber Michael R.
Published: October 2019

Abstract 398

Most t(11;14)(q13;q32) breakpoints in mantle cell lymphoma (MCL) are scattered across a large genomic region centromeric to the CCND1 gene on chromosome 11q13. However, few t(11;14) breakpoints outside the major translocation cluster (MTC) have been sequenced. We report our analysis of 56 IGH-CCND1 fusion sequences from 32 non-MTC cases of MCL. Our analysis reveals remarkable breakpoint diversity at both CCND1 and IGH loci. The CCND1 breakpoints are located from 2 kb to 331 kb from the CCND1 gene, including 12 breakpoints (38%) in the 220kb region centromeric to the MTC, which is itself located 110 kb centromeric to the CCND1 gene. Twenty-one cases had a JH coding end breakpoint on the der(14) chromosome and a DH coding end breakpoint on the der(11). Two cases had der(14) and der(11) breakpoints derived from the coding and signal ends of the same JH or DH gene segment; one case had a JH/DH breakpoint on the der(14) and a VH breakpoint on the der(11); and one case had a breakpoint in the JH region located >100 bases from the nearest RSS motif, suggesting a RAG-independent break at IGH. No der(11) breakpoint could be amplified in eight cases. In sixteen cases (50%), one or both CCND1 breakpoints were within 4 bases of a CpG dinucleotide, a feature characteristic of translocation breakpoints in many human B cell lymphomas. Three CpG-associated “microclusters” were identified, i.e. breakpoints in two different tumors located at or near the same CpG site. Breakpoints in the sixteen (50%) “non-CpG” cases showed a significant association with AID hotspot motifs at the CCND1 locus. In addition, the non-CpG breakpoints were more likely to: 1) be located telomeric to the MTC, 2) involve 3' JH and 5' DH gene segments, and 3) be associated with immunoglobulin lambda light chain restriction; features that suggest occurrence at a late stage of pre-B cell maturation. In contrast, the CpG-associated breakpoints were: 1) more likely to be centromeric to the MTC, 2) not biased in their JH or DH segment usage, and 3) associated with kappa light chain restriction; features suggesting occurrence in an earlier pre-B cell or pro-B cell. Our results implicate AID in chromosomal breakage at both CpG and non-CpG sites within the CCND1 locus and suggest that AID and RAG collude to generate the chromosomal breaks underlying the t(11;14). Our findings also suggest that IGH-CCND1 rearrangements can occur at different stages of pre-B cell maturation. This study provides novel insights into the mechanism and developmental timing of the t(11;14) in human MCL, features that are likely to be relevant to a broad range of human lymphomas.

Disclosures:

Greisman: Signature Genomics, LLC: Patents & Royalties. Yi:Signature Genomics, LLC: Patents & Royalties.
Factors Predicting Early Mortality in Patients with Newly Diagnosed Multiple Myeloma,
Authors: Rana Vishal , Srivastava Geetika , Hayman Suzanne R , Buadi Francis K , Gertz Morie A , Lacy Martha Q , Greipp Philip R. , Zeldenrust Steven R , Dispenzieri Angela , Kyle Robert A , Lust John A , Short Kristen Detweiler , Dingli David , Russell Stephen J. , Rajkumar S. Vincent , Kumar Shaji
Published: October 2019

Abstract 3981

Background:

Patients with multiple myeloma (MM) can present with life threatening complications including lethal infections during the disease course. The mortality is high during the early period following diagnosis, mostly as a result of complications of the disease or treatment. It is not clear if we can identify patients at the highest risk of early death based on the presenting clinical and laboratory features.

Methods:

From among 1545 patients seen at our institution between Jan 1999 and Dec 2008, we identified 265 patients who died within 12 months of diagnosis. For each of these patients we identified two “controls” who had at least 12 months of follow up, were alive at the time of last follow up and were closest to the ‘case' patient in terms of time of diagnosis. We performed logistic regression using the clinical and laboratory features, to identify parameters that predict for 12-month mortality and to determine the best cutoffs.

Results:

This study included 265 patients as cases and 530 controls. The gender distribution was similar in the two groups. We examined the impact of age, performance status (PS), hemoglobin, platelets, serum creatinine, calcium, LDH, albumin, B2M, free light chain difference, plasma cell labeling index, ISS stage, risk category and exposure to novel agents upfront. Based on the results of univariate and then multivariate analysis – age> 72, ECOG PS>2, Calcium >11.3 and ISS stage 3 were found to be significant. We developed the risk score using 1 point for each adverse factor, Age> 72, PS > 2, ISS 3, and Calcium > 11.3. The odds ratio of patients dying in the first year was 2.7, 9.2 and 37 in the presence of one, two and three or more risk factors compared to none of the risk factors. We then looked at the impact of the initial therapy on outcome. 279 patients (35%) received one of the novel agents (thalidomide, lenalidomide or bortezomib) as initial therapy. The odds ratio for dying in the first year was 0.35 for patients receiving a novel agent compared to the rest. The impact of the novel agent was independent of the risk score, with the risk score predicting outcome in both groups.

Conclusions:

In newly diagnosed MM advanced age, poor performance status, ISS stage and high calcium were associated with early mortality. If eligible all patients should get the benefit of use of novel agent upfront. Identifying these patients at the time of diagnosis is important and should help develop better risk-adapted strategies.

Disclosures:

No relevant conflicts of interest to declare.
Flt3-Ligand Plays a Critical Role in Development and Function of CD8+/TCR− Facilitating Cells in Bone Marrow,
Authors: Huang Yiming , Miller Thomas , Xu Hong , Wen Yujie , Ildstad Suzanne T
Published: October 2019

Abstract 4003

Graft facilitating cells (FC) are a CD8+/TCR− bone marrow subpopulation that enhance engraftment of purified hematopoietic cells (HSC) in allogeneic mouse recipients without causing graft-versus-host disease. They also enhance engraftment of suboptimal numbers of syngeneic HSC. FC induce antigen-specific CD4+/CD25+/FoxP3+ regulatory T cells in vivo. The major subpopulation in FC is resembles plasmacytoid precursor dendritic cells (p-preDC) both phenotypically and functionally. Treatment of mice with Flt3 ligand (FL) results in a significant increase in FC in peripheral blood (PB) and FL-expanded-PB FC enhanced HSC engraftment. In this study, we evaluated the role of FL in FC development using FL-KO mice. We first compared FC from FL-KO B6 mice with FC from B6 mice to evaluate the FC total cellular composition. The number of FC was significantly decreased in FL-KO mice compared to wild type controls (P = 0.0003). The number of p-preDC FC was also significantly decreased (P = 0.0001), suggesting that FL is important in the development of p-preDC FC. Next, we tested whether FL-KO FC facilitate engraftment of HSC in allogeneic recipients. FC were sorted from FL-KO B6 mice and HSC (C-Kit+/Sca-1+/Lin−) were sorted from B6 mice. 10,000 B6 HSC plus 30,000 FL-KO FC were transplanted into NOD recipients conditioned with 950 cGy of total body irradiation. Controls received 10,000 B6 HSC with or without 30,000 B6 FC. Only 36% (5 of 14) NOD recipients of B6 HSC alone engrafted and two mice survived up to 160 days (Figure). Sixty-three percent (5 of 8) of recipients transplanted with B6 HSC + FL-KO B6 FC engrafted and only one mouse survived up to 160 days. Seventy-five percent (9 of 12) recipients of B6 HSC + B6 FC engrafted and seven of the mice survived more than 160 days. The level of donor chimerism in recipients of B6 HSC + B6 FC (57% ± 10%) was significantly higher than recipients of B6 HSC + FL-KO B6 FC (14% ± 3%; P = 0.003) or B6 HSC alone (22% ± 6%; P = 0.005). These data demonstrate that FL-KO FC fail to facilitate durable allogeneic HSC engraftment, suggesting that flt3-ligand plays a critical role in development of functional FC.

Disclosures:

Ildstad: Regenerex, LLC: Equity Ownership.
Donor B Cells in Transplants Augment Clonal Expansion and Persistence of Pathogenic Donor CD4+ T Cells in Autoimmune-Like Chronic Graft-Versus-Host Disease,
Authors: Young James Sundblom , Wu Tao , Chen Yuhong , Zhao Dongchang , Johnston Heather F , Li Xiaofan , Forman Stephen J. , Zeng Defu
Published: October 2019

Abstract 4021

Chronic graft-versus-host disease (cGVHD) manifests with autoimmune symptoms (i.e. increased serum levels of autoantibodies, donor T cell infiltration in skin and salivary gland tissues, and collagen deposition in skin tissues). Donor B cells have been indicated to play an important role in the pathogenesis of cGVHD in mouse models as well as in patients, but the mechanisms remain unclear. In the current studies, using a cGVHD mouse model of DBA/2 donor to MHC-matched BALB/c host, we have observed that donor B cells are activated by donor CD4+ T cells in transplants to upregulate MHC II and co-stimulatory molecules and produce IgG autoantibodies; in turn, donor B cells mediated clonal expansion of autoreactive donor-type CD4+ T cells, as judged by TCR spectratyping and in vitro T cell proliferation in response to donor- and host-type APCs. Kinetic studies showed that the presence of donor B cells in transplants was associated with persistence of GVHD target tissue damage (i.e. sclerodermatous skin) and persistence of donor CD4+ T infiltration in the tissues in which there is an expansion of Th1 and Th2 but not Th17. The presence of donor B cells in transplants also markedly augmented tissue damage in prototypical cGVHD targets such as the salivary gland. Sorted donor CD4+ T cells from primary recipients given donor B cell-containing transplants but not from the primary recipients given B cell-depleted transplants caused cGVHD-like tissue damage in the skin and salivary gland of adoptive recipients. These results indicate that donor B cells in bone marrow transplants play an important role in the generation and expansion of pathogenic CD4+ T cells that mediate chronic GVHD tissue damage.

Disclosures:

No relevant conflicts of interest to declare.
A Single Nucleotide Polymorphism in the NLRP3 Gene Is Associated with Acute Graft-Versus-Host Disease After HLA-Matched Unrelated Bone Marrow Transplantation,
Authors: Espinoza Luis J. , Takami Akiyoshi , Nakata Katsuya , Onizuka Makoto , Kawase Takakazu , Morishima Yasuo , Fukuda Takahiro , Kodera Yoshihisa , Nakao Shinji
Published: October 2019

Abstract 4073

NOD-like receptor family, pyrin domain containing 3 (NLRP3) is an innate immune receptor that exerts functions in the regulation of inflammation and apoptosis. Recent studies have shown that the single nucleotide polymorphism (SNP) rs10754558 (C>G) at the 3' untranslated region of NLRP3 gene is functional and is associated with various immunological diseases. Allele G is linked with a higher activity of NLRP3 than allele A, and plays important roles in increased susceptibility to allergic reactions and in protection of HIV infection. This study retrospectively examined the impact of the NLRP3 genotype of a total 659 recipients with hematologic malignancies and their unrelated donors on the clinical outcomes in unrelated HLA 12/12 matched bone marrow transplantation (BMT) through the Japan Donor Marrow Program. The genotype frequencies of G/G, G/C and C/C were 19%, 50% and 31% in recipients and 18%, 49% and 32% in donors (P =0.79). The donor G/G or G/C genotype was associated with a significantly higher incidence of grades III to IV acute graft-versus-host disease (GVHD; 15% vs. 7%, P =0.004; Fig 1B) and a trend toward a higher incidence of grades II to IV acute GVHD (34% vs. 27%, P =0.06; Fig 1A), while no significant differences between the G/G genotype and G/C genotype were seen. The donor G/G or G/C genotype remained statistically significant in the multivariate analysis for the development of grades III to IV acute GVHD (hazard ratio [HR], 2.18; 95% confidence interval [CI], 1.22 to 3.90; P =0.009) as well as a trend toward an association with grades II-IV acute GVHD (HR, 1.31; 95% CI, 0.96 to 1.80; P =0.09). The recipient NLRP3 genotype did not significantly influence the transplant outcomes. These results suggest an association of the donor NLRP3 genotype with the development of acute GVHD after unrelated BMT. Genotyping for the NLRP3 rs10754558 could be useful in donor selection and risk-adapted management of transplanted patients, and may furthermore offer some novel therapeutic insights into the mechanisms of acute GVHD.

Disclosures:

No relevant conflicts of interest to declare.
Graft Source and HLA-Matching Degree-Based Analyses of Long-Term Outcomes of Unrelated Donor Transplants in Adult High-Risk Acute Lymphoblastic Leukemia: Similar Outcomes Between Bone Marrow and Peripheral Blood Progenitor Cells Transplants,
Authors: Lee Seok , Yahng Seung-Ah , Lee Sung-Eun , Cho Byung-Sik , Eom Ki-Seong , Kim Yoo-Jin , Chung Nak-Gyun , Kim Hee-Je , Min Chang-Ki , Kim Dong-Wook , Lee Jong-Wook , Min Woo-Sung , Park Chong-Won
Published: October 2019

Abstract 4167

Background:

Adults with high-risk acute lymphoblastic leukemia (ALL) have a poor outcome with standard chemotherapy and usually undergo unrelated donor stem cell transplantation (URD-SCT) if a matched sibling donor is not available. However, long-term results of URD-SCT, especially based on HLA-matching degree and graft source, are scarce in adult high-risk ALL. To assess the effect of HLA-matching degree and graft source, we analyzed long-term outcomes of 109 consecutive URD transplants with adult high-risk ALL (2000–2008).

Method:

Using allele-level typing, graft sources were classified as 8/8-matched bone marrow (BM; n=31), 8/8-matched peripheral blood progenitor cells (PBPC; n=19), 7/8-matched BM (n=35), and 7/8-matched PBPC (n=24). Patients received total body irradiation (≥12 Gy)-based full-intensity (n=95) or reduced-intensity (fludarabine plus melphalan; n=14) conditioning regimens. All patients received the same graft-versus-host disease prophylaxis consisting of tacrolimus plus methotrexate. Antithymocyte globulin was administered to all 7/8-matched transplants.

Result:

After a median follow-up of 57 months, the 5-year cumulative incidence of relapse was 19% for 8/8-matched BM, 16% for 8/8-matched PBPC, 37% for 7/8-matched BM, and 48% for 7/8-matched PBPC (P=0.013). Conversely, no significant difference in the 5-year cumulative incidence of non-relapse mortality was observed between each group of patients. Consequently, disease-free survival (DFS) at 5 years was inferior using 7/8-matched BM (46%) or 7/8-matched PBPC (42%), compared with 8/8-matched grafts (65% for BM and 58% for PBPC) (P=0.044). However, when considering pre-transplant disease status and conditioning intensity, no influence of HLA-matching degree and graft source on outcomes was found in transplants receiving full-intensity conditioning in first complete remission (CR1). Notably, outcomes were similar between BM and PBPC transplants in each group of patients showing the same HLA-matching degree. Regardless of HLA-matching degree and graft source, pre-transplant disease status (CR1 versus >CR1) was an independent predictive factor affecting relapse (RR 3.09, P=0.005) and DFS (RR 2.69, P=0.003). The absence of chronic graft-versus-host disease was also associated with higher relapse (RR 5.60, P<0.001) and poorer DFS (RR 2.49, P=0.005).

Conclusion:

Our long-term data suggest that outcomes are similar for transplantation using BM or PBPC in the setting of 8/8-matched or 7/8-matched URD-SCT in adult high-risk ALL.

Disclosures:

No relevant conflicts of interest to declare.
The Profile of Endothelial Function in Children with ALL Is Associated with the Risk Stratification Determining the Outcome – a Pilot Study
Authors: Niedzielska Ewa , Doroszko Adrian , Chybicka Alicja , Szuba Andrzej
Published: October 2019

Abstract 4230

Background:

Endothelial dysfunction (ED) is characterized by impaired balance between pro- and anti-aggregatory, pro- and anti-inflammatory factors as well as vasodilative and vasoconstrictive action of numerous metabolic and signaling pathways. ED is an important factor worsening the outcome in severe diseases. The aim of this study was to assess if the profile of endothelial function during the treatment of ALL might be associated with the risk stratification and with the outcome.

Material and Methods:

N=18 children at age of 4–18 years with ALL, treated with the ALLIC- BFM 2002 protocol were investigated. Plasma levels of the NO pathway metabolites (L-Arginine, ADMA – an endogenous competive eNOS inhibitor), markers of endothelial inflammatory and aggregatory function (VCAM-1, ICAM-1, E-selectin, P-selectin and PAI-1), lipid peroxidation (MDA – malonyldialdehyde) were analyzed at baseline, then during the 33rd and 78th day of treatment. Results were compared between three subgroups: standard risk, intermediate risk and high risk.

Results:

Subjects in the high risk groups were characterized by increased baseline lipid peroxidation, as assessed by the MDA levels in comparison to those in the standard risk group (8.56±2.14U/ml vs. 3.57±0.81U/ml, respectively, p<0.05). In the high risk group low E-selectin levels at baseline (32.1±6.1ng/ml vs. 101.3±11.8ng/ml in the standard risk group, respectively, p<0.05), as well as high NO production at the beginning of the M protocol, assessed by the L-Arg/ADMA ratio (88.6±11.6ng/ml vs. 41.7±6.4ng/ml, respectively, p<0.05) were observed. Moreover, increase in the PAI-1 level during the therapy was associated with smaller risk for poor outcome.

Conclusions: Increased lipid peroxidation, low E-selectin at baseline, as well as increased NO bioavailability, decreased PAI-1 levels at the beginning of the M protocol are common feature in children classified to the high risk group. Low NO bioavailability at baseline and high at the beginning of the M protocol as well as decreased anti-inflammatory and antiaggregatory function of endothelium at the beginning of the M protocol are associated with higher risk for poor prognosis.

Disclosures:

No relevant conflicts of interest to declare.
Copy Number Alterations of PAX5, CDKN2A/B Genes Rather Than IKZF1 gene Are Associated with Pathogenesis of Childhood ALL in Korean Assessed by Multiplex Ligation-Dependent Probe Amplification
Authors: Han Dong Kyun , Yu Li , Tran Huong Thi Thanh , Kim Hee Nam , Lee Il Kwon , Baek Hee Jo , Bae Sul Hee , Kim Hyeoung Joon , Kook Hoon , Hwang Tai Ju
Published: October 2019

Abstract 4231

Background:

Recent genomic studies have analyzed genetic alterations and gene expression in childhood acute lymphoblastic leukemia (ALL), and detected multiple new submicroscopic genetic abnormalities in key cellular pathways, and also identified new prognostic markers and therapeutic targets. More than 50 recurring genetic alterations have been identified, and these genes are known to play key or putative roles in lymphoid development and leukemogenesis. Multiplex Ligation-dependent Probe Amplification (MLPA) is a rapid multiplex PCR based technique that allows the comparative quantification of multiple sites. However, there have been no reports on the MLPA based copy number alterations (CNA) of childhood ALL in Asian countries. The aim of this study is to reveal the CNA of genes involved in lymphoid differentiation and cell cycle control in Korean children with ALL.

Patients and Methods:

Reference ranges for individual MLPA probes were established from a group of 30 healthy control subjects. The MLPA assay was performed for 121 children with ALL in Korea to target those genes including the lymphoid differentiation genes (BTG1, EBF1, IKZF1, and PAX); cell cycle control genes (CDKN2A/B and RB1); transcriptional factors regulating genes (ETV6); and those deleted from the PAR1 region (IL3RA, CRLF2 and CSF2RA). We also evaluated the prognostic impact of these abnormalities.

Results:

Out of the 121 patients analyzed in our study, 96 (79%) displayed CNA in at least one gene: PAX5, 49 (40%); CDKN2A, 42 (35%); CDKN2B, 35 (29%); IKZF1, 22 (18%); ETV6, 22 (18%); EBF1, 16 (13%); RB1, 16 (13%); BTG1, 14 (12%); CRLF2, 12 (10%); IL3RA, 12 (10%); CSF2RA, 11 (9%). Thirteen of 121 (11%) patients relapsed. There was no significant correlation between these CNA and the recurrence of ALL.

Conclusion:

These results suggest that CNA of PAX5, CDKN2A/B may play an important role in the pathogenesis of childhood ALL in Korea, contrasting to those findings from western countries showing a significant correlation between IKZF1 and childhood ALL. Several factors should be considered to explain a discrepancy between our results and the previous studies, which include different genotype frequencies in polymorphisms and varied susceptibility to ALL in different ethnic groups. Further studies incorporating larger number of cases and analyzing other possible genes are warranted in childhood ALL.

Disclosures:

No relevant conflicts of interest to declare.
Dexrazoxane Use in Pediatric Patients with Acute Lymphoblastic or Myeloid Leukemia: Analysis of a National Cohort of Patients in the Pediatric Health Information Systems Database From 1999 to 2009
Authors: Sepe Dana , Fisher Brian T. , Seif Alix E. , Huang Yuan-Shung V. , Li Yimei , Aplenc Richard
Published: October 2019

Abstract 4242

Background:

Acute lymphoblastic leukemia (ALL) and acute myelogenous leukemia (AML) account for approximately 26% of all pediatric cancers. Anthracyclines are critical in the treatment of ALL and AML; however, their use is limited by cardiotoxicity. Dexrazoxane (DZX) is an FDA-approved cardioprotective agent that chelates intracellular free iron and iron bound to anthracyclines. Evidence for the efficacy of DZX as a cardioprotectant in children is limited, but available data support a short term cardioprotective effect in patients with ALL. The frequency of DZX use in pediatric cancer patients at high risk of developing cardiac toxicity is unknown.

Objective:

We sought to describe patterns of DZX use between 1999 and 2009 in a retrospective cohort study of pediatric patients diagnosed with ALL or AML in 43 pediatric hospitals across the United States in the Pediatric Health Information Systems (PHIS) database.

Methods:

Patients previously identified and validated as having de novo ALL and AML at these PHIS hospitals were included. Demographic data, as well as chemotherapy and DZX use were obtained from PHIS.

Results:

Of 8733 patients with de novo ALL and 2556 with de novo AML, 207 and 52 received DZX, respectively. The proportion of patients receiving DZX was higher in older children with ALL or AML and in African-Americans and males with ALL (Table 1). There was no trend in the proportion of patients receiving DZX per year in either group (Figure 1). DZX use varied by region in ALL, with 55% of the patients receiving DZX being treated in the northeast, but was not significantly different in AML. There was substantial variability in prescribing practices across institutions (Figure 2). Most patients with ALL and AML received the first dose of DZX in the first 30 days (67% and 31%, respectively) or >360 days from their first leukemia admission (23.5% and 31%, respectively).

Conclusions:

To our knowledge, this is the only description of DZX use in patients with ALL and AML using national, population-based data. Older children and those treated in the Northeastern U.S. were more likely to have received DZX, with the first dose being given either early or late in the study period. In general, DZX administration was relatively rare and was driven by only a few institutions, especially in ALL patients. This lack of universal acceptance of DZX is likely multi-factorial, including concerns about acute and long-term side effects, impact on the antitumor effect of anthracyclines, and risk for secondary malignant neoplasm. Work is ongoing to substantiate or refute these concerns using PHIS data.

Disclosures:

No relevant conflicts of interest to declare.