bluuebunny/crossref_metadata_2025 huggingface dataset:
Idarubicin Appears Equivalent to Dose-Intense daunorubicin for AML Induction
Authors: Trifilio Steven , Zhou Zheng , Mehta Jayesh , Czerniak Colleen , Pi Judy , Koslosky Molly , Greenberg Deborah , Pantiru Mihaela , Altman Jessica
Published: October 2019

Abstract 3581

Worldwide cancer drug shortages have recently required the substitution of daunorubicin, the “gold standard” anthracycline for idarubicin for induction therapy in acute myeloid leukemia(AML). Previously published randomized trials have shown idarubicin (12/m2) to be equal to, or better than daunorubicin (45–50mg/m2) for achieving complete remission(Blood. 1991 Apr 15;77(8):1666–74). It is currently unknown whether these results can be extrapolated when compared to intensified doses of daunorubicin(90mg/m2), shown to improve the CR rate when compared to 45 mg/m2 (N Engl J Med. 2009 Sep 24;361(13):1249–59). We therefore conducted an observational study to compare CR rates in AML patients who received either daunorubicin 90mg/m2 or idarubicin 12mg/m2 for the treatment of newly diagnosed AML.

Methods:

Medical records were used to identify newly diagnosed patients with AML who received daunorubicin 90mg/m2(Dau-90) or idarubicin 12mg/m2(Ida-12) between 1/2007 and 6/2012. Patients with APL were excluded. MDS patients who evolved to AML were included. AML was diagnosed by WHO criteria. Patients received daunorubin 90mg/m2 IV bolus or idarubicin 12mg/m2 IV bolus on days 1–3. Cytarabine 100mg/m2 by continuous infusion was given concomitantly on day 1–7 to both groups. All patients underwent marrow biopsy on day 14 after initiation of therapy. If residual disease was found, patients were considered treatment failure. Patients without residual disease were re-biopsied around the time of WBC recovery to assess CR. CR rates are reported after a single induction course.

Results:

28 Ida-12 and 37 Dau-90 patients were identified. Table 1 shows patient demographics and outcomes. There was no significant baseline difference between the 2 study arms for gender, age, weight, maximum WBC prior to therapy, cytogenetic risk group, percent of patients with FLT-3 ITD or NPM mutations, or combined risk factors. A non-significant trend was observed in the percent of marrow blasts prior to therapy and in the number of patients>60years(but not for age >55) within the Ida-12 study arm. Overall CR was similar between the Ida-12 and Dau- 90 treatment groups(p<0.1072) Subset analysis shows CR rates were significantly higher in Ida-12 treated patients who had an unfavorable karyotype(p<0.0359) or unfavorable combined cytogenetic risk(0.0388) or for age > 55 years(p<.0063). Overall morbidity and mortality was similar between groups.

Conclusion:

Ida-12 appears to be as effective as Dau-90 for achieving CR after a single induction course. Thus, Thus, substitution of Ida-12 for Dau-90 during times of drug shortages appears acceptable. Ida-12 may potentially be superior for patients >55 years or for those with unfavorable cytogenetics. These results warrant validation from a randomized clinical trial.

Disclosures:

No relevant conflicts of interest to declare.
Growth Inhibition of a Myeloid Leukemia Cell Line with 5q Deletion by Beta-Catenin Inhibition
Authors: Seba Amber D. , Wang Qi , Ming Ming , Qian Zhijian
Published: October 2019

Abstract 3608

As the population ages, the incidence of AML with complex cytogenetics continues to increase. These patients have a poor prognosis with 5% percent of patients diagnosed surviving 5 years. New strategies are needed to improve survival in AML patients. 5q deletion is present in 6–10% of cases of AML, and is a common chromosome abnormality in therapy-related AML (t-AML). 5q deletion is associated with haplo-insufficiency of the APC gene in hematopoietic stem cells and progenitors, leading to deregulation of the Wnt pathway and stabilization of beta- catenin (Wang, J Blood 2010). Loss of APC causes rapid exhaustion of hematopoietic stem cells and progenitors in vivo and leads to the accumulation of beta-catenin (Qian, Z et al JEM 2008). Beta-catenin is required for the development of leukemia stem cells in AML, but it is not required for the self-renewal of normal hematopoietic stem cells (Wang, Y et al Science 2010). Development of treatment strategies aimed at blocking the Wnt pathway through suppression of beta-catenin may improve and prolong remission rates.

The UoCM1 cell line maintains the unique characteristics of del(5q) leukemia (Qian et al, PNAS 2002). Western Blot shows that the expression of beta-catenin was higher in UoCM1 cells versus REH and MV4–11 cell lines, which do not have del(5q). To block the activation of Wnt signaling, through suppression of beta-catenin, we treated UoCM1, REH and MV4–11 cells with 100uM indomethacin. The UoCM1 cells showed 30% growth inhibition while REH and MV-4 cells displayed 10% growth inhibition. The down-regulation of beta-catenin in UocM1 is confirmed by Western Blot. Curcumin is a dietary polyphenol existing in Indian spice turmeric. We showed suppression of beta-catenin by curcumin in 293T cells by luciferase assay. Next, we treated UoCM1 and MV4–11 cells with 5uM or 10 uM curcumin. The growth of UoCM1 cells was significantly inhibited by curcumin as compared to MV4–11 cells. Treatment of UoCM1 cells with 10 uM curcumin produced 87% growth inhibition, while the growth inhibition was 29% for MV4–11 cells. 5uM concentrations of curcumin caused 48% growth inhibition in UoCM1 cells versus 16% in the MV4–11 cell line. Western Blot was performed to confirm that beta-catenin is down-regulated by curcumin, in the UoCM1 cell line.

In summary, blockade of the Wnt pathway through inhibition of beta-catenin suppresses cell growth in UoCM1 leukemia cells, with 5q deletion. Suppression of beta-catenin in combination with cytotoxic therapy may provide a novel means of treating leukemia in patients with a 5q deletion that both improves remission rates and prevents relapse.

Disclosures:

No relevant conflicts of interest to declare.
Outpatient Treatment of Symptomatic Pulmonary Embolism: A Systematic Review and Meta-Analysis
Authors: Piran Siavash , Le Gal Gregoire , Wells Phil , Righini Marc , Carrier Marc
Published: October 2019

Abstract 361

Background:

Patients with deep vein thrombus (DVT) can safely be treated as outpatients using subcutaneous low molecular weight heparin (LMWH). However the role of outpatient treatment in patients diagnosed with a pulmonary embolism (PE) is controversial. This practice is not accepted in many centers and majority of patients are still admitted to the hospital for observation. Clinicians are reluctant to discharge patients due to insufficient data supporting the safety of outpatient management of PE.

Purpose:

To determine the safety of outpatient treatment of acute symptomatic PE and the outcomes associated with outpatient management of PE including venous thromboembolism (VTE) recurrence, major bleeding, fatal PE, fatal intracranial hemorrhage (ICH), and overall mortality.

Methods:

A systematic literature search strategy was conducted using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and all EBM Reviews of published studies up to June 2012. We included randomized controlled trials (RCTs) and prospective cohort studies. We calculated the pooled proportions for the different outcomes at 3-months of follow-up. Ninety-five percent confidence intervals (95% CI) were calculated for each rate using the averaged, inverse variance-weighted estimates from each study.

Results:

Thirteen studies met all the inclusion criteria (3 RCTs and 10 prospective cohort studies). A total of 2458 patients were included in the systematic review. Different risk stratification methods were used to identify low risk patients with PE such as the pulmonary embolism severity index (PESI), the Geneva prognostic score, clinical gestalt and/or laboratory markers. The risk of recurrent VTE in patients with PE managed as outpatients was 1.64% (95% CI 0.69 – 3.0%; I2: 70.7%) during the 3 months follow-up period. The rate of fatal PE was 0.70% (95% CI 0.14 – 1. 7%; I2: 72.6%). The rates of major bleeding and ICH were 1.14% (95% CI 0.35 – 2.34%; I2: 72.8%) and 0.29% (95% CI 0.06– 0.68%; I2: 0%), respectively. The overall mortality rate was 2.3% (95% CI 0.41 – 5.7%; I-square: 92.8%). The I2 was moderate to high for most proportions, likely due to difference in the baseline characteristics (e.g. the inclusion of cancer patients in some studies).

Conclusion:

Independent of the risk stratification methods used, the rate of adverse events associated with outpatient PE treatment seems low. Based on our systematic review and pooled meta-analysis, numerous patients with acute PE can safely be treated as outpatients.

Proportion meta-analysis showing the risk of recurrent VTE in patients with PE managed as outpatients for a 3 month follow up period.

Disclosures:

No relevant conflicts of interest to declare.
High Efficiency of ICE (Ifosfamide-Carboplatin-Etoposide) in Relapse/Refractory Primary Central-Nervous System and Intra-Ocular Non Hodgkin Lymphoma, After First Line Treatment Containing High Doses of Methotrexate and Cytarabine. A Monocentric Retrospective Study From 2010 to 2012 On 17 Cases
Authors: Choquet Sylvain , roos Weil Damien , Xuan Khe Hoang , Cassoux Nathalie , Merle-Beral Helene , Leblond Veronique
Published: October 2019

Abstract 3664

Background:

Primary central nervous system lymphoma (PCNSL) and primary intra-ocular lymphoma (PIOL) are at very high risk of relapse after a first line treatment, and then carry a very poor prognosis. Autologous stem cell transplantation (ASCT) can offer prolonged responses but its results clearly depend on efficiency of salvage chemotherapy (Soussain, haemtologica, 2012). Since recent publications on first line treatment of PCNSL and PIOL recommend high dose methotrexate (Mtx) and cytarabine (AraC) (Ferreri, Lancet 2009), salvage chemotherapy must use other drugs with high level of penetration in the central nervous system (CNS). In this setting, ICE regimen, validated in systemic non Hodgkin lymphoma, seems to be appropriated but no data is published in PCNSL and PIOL.

Methods:

From june 2010 to may 2012, all relapse/refractory PCNSL and PIOL treated in first line by high doses of Mtx and AraC in the Pitie-Salpetriere Hospital, Paris, France, where treated by ICE regimen : ifosfamide (5g/m2 at day 2), carboplatine (AUC 5 at day 2) and etoposide (100mg/m2/d days 1 to 3). Doses where adapted on patient general status and ASCT proposed when possible.

Results:

Seventeen patients have been treated, 7 females and 10 males, median age 62 [28–84]. Four where refractory and 13 in relapse, with a mean progression free survival (PFS) of 368 days [85–1763], 4 had a second line, one a third before ICE. At moment of ICE treatment, localizations where 10 CNS, 2 CNS + PIOL, 3 PIOL and 2 meningitis. The mean number of cycles was 4 [1–6] and 4 patients needed a dose reduction. During treatment, grade 3/4 WHO toxicities where: 6 neutropenic fever (one death), 5 anemia, 9 neutropenia, 10 thrombopenia and one CNS complication (coma and hypersalivation). ASCT have been made in 6 patients (5 in CR, 1 in PR) and are pending in 3. Complete response (CR) have been obtained in 13 patients (76%), partial in 2. With a mean follow-up of 405 days, 6/15 patients in response relapsed (only one after ASCT), in a median of 81 days, 9 patients died (7 by progression, one during treatment and one in CR). Median Overall survival (OS) was 220 days for all patients but was not reached in case of ASCT.

Conclusion:

ICE regimen is very effective in relapse/refractory PCNSL and PIOL heavily treated by high dose Mtx and AraC. This efficacy can allow to perform ASCT in eligible patients, chemosensitivity being the most important factor influencing the OS and PFS after ASCT. ICE can represent a new standard in this setting.

Disclosures:

Leblond: Roche: Advisory Board Other, Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; Janssen-Cilag: Honoraria.
R-HCVAD Alternating with R-Methotrexate Cytarabine in Younger Patients (pts) with IH and High-Risk Age Adjusted-IPI DLBCL
Authors: Oki Yasuhiro , Westin Jason R. , Fowler Nathan , Neelapu Sattva , Hagemeister F.B. , McLaughlin Peter , Kwak Larry W. , Romaguera Jorge Enrique , Fanale Michelle , Younes Anas , Rodriguez Maria A. , Orlowski Robert Z. , Wang Michael , Ouzounian Souzanne T , Samaniego Felipe , Fayad Luis
Published: October 2019

Abstract 3707

Background:

The management of pts with untreated, high-risk DLBCL needs improvement. R-HCVAD/R-MTX-ARA-C is a regimen with significant activity in Burkitt's, ALL, and mantle cell lymphomas. The aim of this phase II study is to evaluate the efficacy and safety of R-HCVAD in patients up to 60 years with IH or High risk DLBCL by age adjusted IPI.

Methods:

Pts with untreated indolent DLBCL with aa-IPI score of 2 or 3 risk were eligible. Treatment was R-HCVAD alternating with R-Methotrexate-cytarabine unless the patient had an effusion that precluded from receiving methotrexate. Prophylactic antibiotics and growth factors were routinely given to pts, and intrathecal prophylaxis were given in patients who were considered to be at high risk for CNS recurrence. Response was assessed every 2 cycles using the International Working Group Response Criteria 2007 incorporating PET scan.

Results:

A total of 48 pts received at least one cycle of treatment and were evaluable for toxicity. Forty-five were evluable for response. Pts characteristics are the followings; male 60%, median age 50 (24–60), elevated LDH 92%; stage IV 79%, III 19%, PS>1 69%, AA IPI IH 42%, High 58%. Pts received a median of 6 cycles (1–6). Two patients died after 1stcycle, 1 due to sepsis, another pulmonary embolism. Another patient refused treatment after the second cycle and died of disease. CR was observed in 83%,PR in 6%, PD 2%. At the moment of this evaluation, with a median follow of 30 months, 35 (73%) are alive in first remission, 2 (4%) died in CR of glioblastoma and anal cancer, 5 (10%) died of disease, 2 are alive with disease, 2 are alive after transplant, and 2 patients died of toxicity.

Conclusion:

R-HCVAD/R-MTX-Cytarabine is a very active regimen in DLBCL with high-risk features. We however observed significant hematological toxicities and early death in this study.

Disclosures:

Fanale: Genetech: Research Funding. Younes:Seattle Genetics: Research Funding; Allos: Research Funding. Wang:Onyx Pharmaceuticals: Honoraria, Research Funding. Fayad:Roche: Research Funding.
Development and Characterization of a Novel Human Xenograft Model Using an MDS Patient-Derived Cell Line
Authors: Rhyasen Garrett , Wunderlich Mark , Mulloy James C. , Starczynowski Daniel T
Published: October 2019

Abstract 3814

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders, defined by ineffective hematopoiesis, blood cytopenias, myeloid dysplasia, and an increased risk of acute myeloid leukemia (AML). Immunodeficient mice engineered to support human tumor xenografts represent a pivotal development in the study of human cancers. The xenograft model has been an attractive approach to interrogate human AML; in contrast, MDS patient samples exhibit negligible or poor engraftment, with no evidence of disease in immunocompromised recipient mice. To circumvent this limitation we developed a novel xenograft mouse model using an MDS cell line, MDSL. The MDSL cell line was derived from the non-leukemic phase of an MDS patient with refractory anemia-ringer sideroblasts, and has maintained growth-factor dependence and sensitivity to Lenalidomide. Two immunocomprismised mouse stains were used for xenotransplantation of MDSL cell: NOD/LtSz-scid IL2RG (NSG) and NOD/LtSz-scid IL2RG-SGM3 (NSGS). NSGS mice are identical to NSG except that they have been engineered to express three human cytokines, SCF, GM-CSF and IL-3, to improve engraftment of human hematopoietic cells. Following transplantation of MDSL cells by either intrafemoral or intravenous injection, NSG and NSGS animals exhibited human cell grafts in the bone marrow, peripheral blood, and spleen. Subsequently, mice developed a fatal disease exhibiting features of human MDS, including anemia and thrombocytopenia, which coincides with clonal expansion and increased human cell graft in all hematopoietic organs. The median survival for NSGS and NSG mice was 21 and 55 days post-injection, respectively. The shortened latency in NSGS mice suggests that the expression of human cytokines accelerates the growth and enhances survival of the MDSL cells in vivo. MDSL cells isolated from the bone marrow of primary recipient mice were capable of initiating an MDS-like disease in secondary recipients. Given that few preclinical options for MDS are available, we also evaluated whether this model is suitable for therapeutic studies. Since MDSL cells are sensitive to Lenalidomide and IRAK1 Inhibitor (Rhyasen et al, ASH 2011), we evaluated the effects of these drugs in the xenograft model. After xenotransplantation of MDSL cells, NSGS mice were administered either Lenalidomide or IRAK1 Inhibitor. Our preliminary findings indicate that mice xenografted with MDSL cells are amenable to drug delivery and show a response to treatment. In summary this work describes a novel xenograft model of human MDS, the first to develop clinical features resembling human disease. In addition, we predict that this model will also be useful for preclinical studies to examine novel and existing MDS therapies.

Disclosures:

No relevant conflicts of interest to declare.
Metabolites of Tryptophan Catabolism Are Elevated in Sera of Patients with Myelodysplastic Syndromes and Inhibit Hematopoietic Progenitor Amplification
Authors: Berthon Céline , Fontenay Michaela , Corm Selim , Briche Isabelle , Lhermitte Michel , Quesnel Bruno
Published: October 2019

Abstract 3843

Introduction:

Tryptophan catabolism, which is mediated by the enzymes indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO), produces kynurenine, which blocks T-cell activation and induces immunosuppression. Kynurenine itself is converted by downstream enzymes into secondary catabolites that also have toxic effects on T cells. Tryptophan catabolism is elevated in many cancers, including acute myeloid leukemia (AML). However, tryptophan catabolites that are downstream of kynurenine have never been investigated in hematological malignancies.

Methods:

We evaluated the serum levels of primary and secondary tryptophan catabolites in a cohort of patients with myelodysplastic syndromes (MDS). Sera were isolated from 132 adult MDS patients after informed consent was obtained in accordance with the Helsinki Declaration. The levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxykynurenine, 3-hydroxyanthranilic acid, and anthranilic acid in the sera were quantified using HPLC. For erythroid cell expansion, CD34+ cells were collected and isolated from the mononuclear cell fractions of cytapheresis products from 3 healthy donors and cultured in liquid medium under erythroid conditions with tryptophan catabolites.

Results:

The MDS patients showed significantly lower levels of tryptophan and higher levels of kynurenine, kynurenic acid, 3-hydroxyanthranilic acid, and anthranilic acid compared with the healthy controls. We also compared the kynurenine and tryptophan levels in the MDS patients with our previous cohort of 112 patients with primary AML. The kynurenine/tryptophan ratios were significantly higher in the MDS patients (median 0.0468 vs. 0.0676). The tryptophan catabolites correlated with cytopenia; higher kynurenine levels were associated with lower hemoglobin levels and higher blast counts and were associated with presence of dysgranulopoiesis. Lower tryptophan levels were found in patients with platelet transfusion dependency. Kynurenic acid levels were higher in patients with dysmegakaryopoiesis. High 3-hydroxyanthranilic and kynurenic acid levels were associated with severe thrombopenia below 20 G/L. IPSS score, cytogenetic, and WHO diagnosis did not associated with any tryptophan catabolite level. The tryptophan catabolites inhibited progenitor expansion during the in vitro culture of hematopoietic cells and reduced the numbers of granulocytes and erythroblasts.

Conclusions:

Thus, MDS patients are characterized by high tryptophan catabolism resulting in elevated primary and secondary metabolites, which both have inhibitory effects on hematopoiesis. These results suggest that IDO or TDO inhibitors should be investigated in MDS.

Disclosures:

No relevant conflicts of interest to declare.
Low Frequency of Molecular Alterations of H3.3-Atrx-Daxx Chromatin Remodeling Component Genes in Myelodysplastic Syndromes (MDS)
Authors: Attieh Youmna , Wei Yue , Yang Hui , Jia Yu , Zheng Hong , Fang Zhihong , Kantarjian Hagop M. , Garcia-Manero Guillermo
Published: October 2019

Abstract 3844

Novel sequencing technologies have allowed identification of a group of highly recurrent genetic mutations in myelodysplastic syndromes (MDS). Of importance, it has been noticed that a majority of these mutated genes in MDS encode important components of epigenetic regulation, including both DNA methylation and histone modifications. This phenomenon highlights the importance of epigenetic mechanisms in the pathogenesis of MDS. Recently, highly recurrent somatic mutations in the Histone H3.3-ATRX-DAXX chromatin remodeling pathway have been documented in pediatric glioblastoma (Schwartzentruber et al. Nature and Wu et al. Nature Genetics 2012), further supporting the importance of epigenetic regulation for tumorgenesis. We therefore examined potential genetic and epigenetic alterations of the same pathway in MDS. First, in a cohort containing 80 samples of MDS whole bone marrow mononuclear cell DNA (representative of both lower and higher risk disease), we performed Sanger sequencing covering genomic areas of reported mutations of H3F3A, H3F3B, ATRX, and DAXX in glioblastoma. Sequenced genomic areas included reported mutations in pediatric tumors: Lys27 and Gly34 of H3F3A and H3F3B; sequences upstream of and within the helices domain of ATRXX; and the whole coding sequence of DAXX. Overall, we only detected one mutation of H3F3A (K27N) in one MDS case (76 year old male with RA; INT-1; diploid). No other reported mutation of H3F3B, ATRX and DAXX genes was detected in any other patients of this MDS cohort. Because of the potential of epigenetic deregulation, we then examined status of DNA methylation for the promoters of ATRX and DAXX in MDS patients by bisulfite pyrosquencing. While no DNA hypermethylation of DAXX promoter was detected, 8 out of 40 (20%) patients had hypermethylation of the CpG island in the promoter region of ATRX. However, six of these eight patients were females. Based on reports of ATRX methylation in healthy females, it is likely that the 6 cases in female patients represent physiological × chromosome inactivation. Finally, we performed RT-PCR analysis using cDNA samples isolated from CD34+ hematopoietic stem cells of 40 MDS patients. Results indicated that expression of ATRX and DAXX were increased by 2 fold (p-value 0.07) and 5.2 fold (p-value 0.0003) respectively compared to control CD34+ cells. The implications of this phenomenon need to be studied further. Taken together, these results suggest that genetic mutations of the H3.3-ATRX-DAXX chromatin remodeling do not play a role in the pathogenesis of MDS.

Disclosures:

No relevant conflicts of interest to declare.
Regional and Racial Differences in Venous Thrombosis in the United States: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study
Authors: Zakai Neil A , McClure Leslie A , Judd Suzanne E , Folsom Aaron R , Lutsey Pamela , Callas Peter , Safford Monika , Cushman Mary
Published: October 2019

Abstract 396

Introduction:

Venous thrombosis (VTE) is thought to be more common in African-origin (black) than Caucasian-origin (white) Americans, however most prior studies are based on administrative databases, are limited in geographic scope, or have few blacks. Studies of VTE with diverse racial and geographic participants and validated VTE events are lacking.

Methods:

Between 2003–07, 30,239 participants were enrolled in REGARDS, 55% were female, 41% were black, and 56% lived in the southeast (by design). Possible VTE events were identified by telephone interviews, review of reported hospitalizations, and review of deaths. VTE events were validated by physician review of hospital records, outpatient notes, imaging studies, and death records. VTE incidence rates by race and region controlling for age and sex were estimated using Poisson regression and racial and regional differences in VTE were evaluated using Cox proportional hazard models controlling for age, sex, region, obesity status, education, and income.

Results:

Among 27,807 individuals free of VTE at baseline, 268 incident VTE events occurred over a mean of 4.7 ± 1.6 years (Table). Blacks and whites had the same age and sex-adjusted VTE incidence (1.8 per 1000 person-years). When stratified by region, blacks living in the southeast had a higher incidence of VTE than whites (2.2 vs. 1.7 per 1000 person-years), while this was not the case in the rest of the US (1.5 vs. 2.0 per 1000 person-years) (Table). This difference in associations by race and region was statistically significant, such that the HR for blacks compared to whites was higher in the southeast (1.3) than in the rest of the country (0.8) even after adjusting for income, education, and obesity (all p-interaction ≤ 0.03) (Table). Further, blacks in the southeast had a higher VTE risk than blacks in the rest of the US (HR 1.5; 95% CI 1.0, 2.3) while there was no geographic disparity for whites (HR 0.8; 95% CI 0.6, 1.1) for the southeast vs. rest of the country.

Discussion:

For the first time, we demonstrate that region of residence significantly influences racial differences in VTE. Prior studies of racial differences in VTE have used administrative databases or studied blacks primarily from the southeast. In REGARDS, blacks in the southeast have higher rates of VTE compared to blacks in the rest of the US, and this is not explained by differences in income, education, and obesity. Whether these findings are due to differences in quality of care, genetic admixture, or novel VTE risk factors needs further study.

Disclosures:

Cushman: Beckman: Honoraria.
Enhancers of Polycomb EPC1 and EPC2 Prevent Accumulation of MYC to Sustain the Oncogenic Potential of MLL Leukemia Stem Cells
Authors: Huang Xu , Somervaille Tim
Published: October 2019

Abstract 400

Dysregulation of the structure and function of chromatin is common in myeloid malignancy. We used a lentiviral screening strategy to target for knockdown ∼270 genes coding for chromatin regulatory proteins in human THP-1 AML cells. THP-1 cells harbor a t(9;11) translocation which is the cytogenetic hallmark of MLL-AF9, found in ∼5% of patients with AML. The strategy identified the EP400 chromatin complex components EPC1 and EPC2 as critical oncogenic co-factors in MLL leukaemia. Knockdown of both EPC1 and EPC2 in human MLL-mutated cell lines and of Epc1 and Epc2 in experimentally initiated murine MLL-AF9 AML cells led to loss of AML cell clonogenic potential, due to induction of apoptosis. The phenotype was rescued by forced expression of human EPC1 or EPC2 in Epc knockdown cells. Epc1 and Epc2 knockdown MLL-AF9 AML cells failed to initiate AML upon syngeneic transplantation into secondary murine recipients, while control cells initiated short latency leukemia. Likewise, xenogeneic transplantation of EPC1 or EPC2 knockdown primary human MLL-AF9 AML failed to engraft recipients, while control cells which engrafted every recipient to variable extent. In complete contrast, knockdown of EPC1 or EPC2 did not adversely impact on either the in vitro clonogenic or in vivo repopulating potential of primary murine KIT+ or human CD34+ normal haematopoietic stem and progenitor cells. These data demonstrate a remarkable selective dependency of MLL-mutated leukemia stem cells, but not normal hematopoietic stem and progenitor cells, on Epc1 and Epc2.

EPC1 and EPC2 are part of an EP400 centred complex with a role in the DNA damage response. The complex is also known to associate with MYC. Consistent with a role for EPC containing complexes in the DNA damage response, Epc1 and Epc2 KD in both normal and leukemic cells induced γH2A.X. However, only in leukemia cells was a transcriptional signature of MYC activation noted together with accumulation of MYC protein, prior to induction of Bim and subsequent apoptosis. This observation reveals a novel mechanism operational in leukaemia cells but not normal myeloid cells by which protein levels of the critical cellular oncogene MYC are limited by EPC/EP400. This counterintuitive observation refines the paradigm for MYC in transformed cells: when the function of EPC and its associated EP400 complex components is inhibited, thus impairing the DNA damage response, MYC accumulates and sensitises cells to apoptotic death. Thus EPC1 and EPC2 are components of a complex which serves to prevent MYC accumulation in myeloid leukemia cells and their sensitisation to apoptosis, thus sustaining oncogenic potential. Therapeutic targeting of this complex may facilitate restoration of the natural tumour suppressor mechanisms that prevent cellular transformation by MYC and enhance chemosensitivity of AML cells.

Disclosures:

No relevant conflicts of interest to declare.
Endogenous Nras G12D/+ and G12D/G12D Distinctly Regulate Self-Renewal and Differentiation of Haematopoietic Stem Cells
Authors: Kong Guangyao , Wang Jinyong , Liu Yangang , Du Juan , Damnernsawad Alisa , Ranheim Erik A. , Ryu Myung-Jeom , Zhang Jing
Published: October 2019

Abstract 4086

How oncogenes regulate adult stem cells to promote tumorigenesis is poorly understood. We and others previously reported that recipient mice transplanted with Nras G12D/+ or Nras G12D/G12D bone marrow cells develop distinct haemtopoietic malignancies. Mice with G12D/+ cells predominantly develop a myeloproliferative neoplasm (MPN) closely resembling chronic myelomonocytic leukemia (CMML), while animals with G12D/G12D cells develop acute T- or B-cell lymphoblastic leukemia (TALL or BALL) and/or MPN, with varying penetrance, which appear to be regulated by the activity of G12D/G12D haematopoietic stem cells (HSCs). Consistent with this notion, we found that G12D/+ HSCs are required to initiate and maintain CMML-like phenotypes in recipient mice and serve as MPN initiating cells. Therefore, we further investigated how endogenous oncogenic Nras signaling regulates the self-renewal and differentiation of HSCs to promote leukemia development in different lineages of cells.

Here we show that G12D/+ signaling results in moderate hyperproliferation and increased self-renewal of HSCs, promoting expansion of myeloid progenitors and consequently myeloid malignancies. In contrast, G12D/G12D leads to excessive hyperproliferation, decreased self-renewal, and depletion of HSCs, which promote expansion of myeloid and lymphoid progenitors and subsequently malignancies in both compartments. Because leukemia development in Nras G12D/+ and G12D/G12D models is tightly associated with ERK1/2 hyperactivation in haematopoietic stem/progenitor cells (HSPCs), we studied the MEK/ERK signaling in HSCs and their downstream multipotent progenitors (MPPs) using a “HSC phosphor-flow” method we developed. Our data demonstrate that ERK1/2 is hyperactiavated in G12D/+ and G12D/G12D HSCs in a dose-dependent manner, while AKT is not affected in G12D/+ and G12D/G12D HSCs. In contrast, both ERK1/2 and AKT are not changed in G12D/+ and G12D/G12D MPPs. As expected, inhibition of MEK/ERK signaling by AZD6244 (a MEK1 inhibitor) rescues the HSC phenotypes and attenuates myeloproliferative neoplasm phenotypes in G12D/+ and G12D/G12D mice. Mechanistic analysis identifies that a cohort of MAPK pathaway genes regulating cell cycle and signaling are significantly differentially expressed in G12D/+ HSCs compared to control or G12D/G12D HSCs. Unlike the prevailing theory based on Ras overexpression studies, depletion of G12D/G12D HSCs is not associated with overexpression of cell senescence genes. Rather, the Wnt and Notch pathways are significantly downregulated in G12D/G12D but not G12D/+ HSCs. Therefore, we propose that endogenous Nras G12D signaling differentially regulates HSCs self-renewal and differentiation through a dose-dependent hyperactivation of ERK1/2.

Disclosures:

No relevant conflicts of interest to declare.
Inducible Costimulator (ICOS) Is up-Regulated in Dogs with Graft Versus Host Disease and Graft Rejection Following Non-Identical Hematopoietic Cell Transplantation
Authors: Graves Scott Stoll , Sato Masahiko , Loretz Carol , Diane Stone , Storb Rainer
Published: October 2019

Abstract 4109

Inducible co-stimulator (ICOS), a member of the CD28 family of costimulatory molecules, is induced on CD4+ and CD8+ T-cells following their activation. Evidence suggests ICOS functions as an essential immune regulator and ICOS blockade is a potential target for allogeneic transplantation. We have used the canine model to develop several strategies for hematopoietic stem cell transplantation that have been successfully translated into the clinic. Here we describe the production and testing of monoclonal antibodies (mAb) directed against canine ICOS and determined the expression profile of ICOS in dogs. Canine ICOS was expressed in an inducible pattern on up to 89% of T-cells activated by Con A, anti-CD3 plus anti-CD28 mAb and alloantigen stimulation. Immunosuppressive effects of ICOS blockade were observed in mixed lymphocyte reactions (MLR) using peripheral blood mononuclear cells obtained from dog leukocyte antigen nonidentical dogs. Significant augmentation of the immunosuppressive effects of ICOS blockade was observed in MLR when anti-ICOS was combined with suboptimal concentrations of cytotoxic T-lymphocyte antigen 4-Ig (CTLA4-Ig) or cyclosporine. ICOS expression was significantly up-regulated on T-cells collected from the peripheral blood, lymph nodes and spleen from dogs undergoing graft rejection or chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. Dogs that remained mixed chimeric expressed ICOS at levels comparable to normal dogs. Analysis of the peripheral blood CD3+ T-cells isolated from dogs showed a significant up-regulation of ICOS expression 3 days but not 6–7 days before the diagnosis of chronic GVHD. Pharmacokinetic studies of 123I-labled anti-canine ICOS showed normal blood clearance profiles. These studies demonstrated that an antagonistic anti-canine ICOS mAb may have application in the prevention or treatment of GVHD in an outbred animal model shown to reliably translate novel hematopoietic cell transplantation therapies to the clinic.

Disclosures:

No relevant conflicts of interest to declare.
Use of FoxP3 Diptheria Toxin Receptor (Foxp3DTR) Donor T Cells to Define the Mechanism Involved in the Inhibition of GvHD by Azacytidine in Vivo
Authors: Cooper Matthew L , Choi Jaebok , Ritchey Julie , DiPersio John F.
Published: October 2019

Abstract 4113

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the primary treatment for high risk and relapsed hematological malignancies. However, the desired graft versus leukemia (GvL) effect is frequently accompanied by Graft versus Host Disease (GvHD) in which donor lymphocytes target host tissues, often resulting in significant morbidity and mortality. We and others have shown that the hypomethylating agent, 5-azacytidine (azaC), can mitigate GvHD in both murine preclinical transplant models and in human clinical trials while maintaining a robust GvL effect. Two mechanisms have been proposed to explain how azaC reduces GvHD: 1) the generation of suppressive regulatory T cells (Tregs, CD4+CD25+Foxp3+) through the in vivo conversion of alloreactive donor T effectors (FoxP3-) into suppressive regulatory T cells (Tregs, CD4+CD25+Foxp3+) via the pharmacologic hypomethylation of the Foxp3 promoter resulting in enhanced gene expression or,1 2) the direct anti-proliferative and pro-apoptotic effects of azaC on allogeneic T cells.2

To assess the importance of azaC-generated Tregs in ameliorating GvHD we obtained Foxp3DTR mice in which Tregs can be selectively ablated (>97%) following the administration of diphtheria toxin (DT).3 To induce GvHD, 1×107 panT cells obtained from Foxp3 DTR mice were injected (CD45.2+) via the lateral tail vein on day 11 post allo-HSCT (CD45.1+) into allogeneic recipients (Balb/c). Transplanted mice were treated with PBS (carrier) or azaC (2 mg/kg) (i.p.) on days +15, +17, +19, and +21, followed by injection (i.p.) of DT or PBS on days +16 +18 +20 (DT 10 μg/kg) and +22 (DT 50 μg/kg) to deplete azaC-induced Tregs. Complete depletion of Tregs by DT was confirmed by flow cytometery.

Mice injected with PBS (n=5) or DT (n=5) (without azaC) developed severe GvHD and died by day 26 post HSCT. In sharp contrast, 100% of mice (n=5) treated with azaC alone survived >100 days, displayed no visible GvHD related symptoms, and gained weight at a similar rate as T cell depleted bone marrow controls. The treatment of mice with azaC +DT (n=5) resulted in significantly prolonged survival compared to the PBS treated mice (p=0.003) but in contrast to the azaC group, failed to survive beyond day 60 (p=0.003). Furthermore, the azaC alone group had higher percentages of Tregs (CD4+/CD25+/FoxP3+, p=0.001), CD3+ T cells (p=0.002), and B220+ B cells (p=0.02) than the azaC +DT group (consistent with less clinical GvHD) and less gastrointestinal GvHD when graded by an independent pathologist. These results suggest that BOTH pharmacologic conversion of alloreactive FoxP3- donor T cells to FoxP3-expressing Tregs and direct toxicity to allogeneic T cells by azaC represent important mechanisms involved in the amelioration of GvHD by azaC in vivo.

Disclosures:

No relevant conflicts of interest to declare.
Chronic Myeloid Leukemia Survival in Older Population in Pre- and Post- Imatinib Era in the United States
Authors: Ghimire Krishna B , Shah Binay K.
Published: October 2019

Abstract 4237

Background:

Median age at diagnosis for CML is 64 years of age. CML survival in elderly population is not well studied. This study was conducted to evaluate the relative survival rates among CML patients older than 50 years in pre- (1991–2000) and post- (2001– 2009) imatinib era.

Methods:

We analyzed the Surveillance, Epidemiology, and End Results (SEER*Stat) 18 registry database to compare 3-year and 5-year relative survival rates among CML patients by gender and age groups (50–69, ≥70) from the pre- (1991–2000) to post- imatinib eras (2001–2009). We used Z-test in the SEER*Stat program to calculate the differences in relative survival rates among different cohorts.

Results:

The 3-year and 5-year relative survival rates for CML patients age ≥50 years in pre- (n=3,848) vs post- (n=6,501) imatinib era were: 44.1±0.9% vs 55.9±0.8%, p=<0.0001, Z-value=10.179 at 3-years and 31.4±0.9% vs 46.9±0.9%, p=<0.0001, Z-value=12.361 at 5-years. The 3-year and 5-year relative survival rates for old (50–69) patients in pre- (n=1,723) vs post- (n=3011) imatinib era were: 57.7 ± 1.2% vs 72.3 ±1.0%, p=<0.0001, Z-value=9.454 at 3 years and 44.8±1.3% vs 64.3±1.2%, P=<0.0001, Z-value= 11.365 at 5 years. The survival rates for elderly (≥70) patients in pre (n= 2,125) and post (n=3,490) imatinib era were: 32.4±1.2% and 41.3±1.1%, p=<0.0001, Z-value=5.806 at 3 years and 19.3±1.1% and 31.2±1.2%, P=<0.0001, Z-value=7.135 at 5 years respectively. Table 1 shows CML survival rates by age and sex in patients older than 50 years of age.

Conclusions:

This study showed significant increase in 3 year and 5 year relative survival rates in post- imatinib era among CML patients older than 50 in all cohorts examined. However, the improvement in survival rates is modest compared to published data from randomized clinical trials.

Disclosures:

No relevant conflicts of interest to declare.
Second Primary Malignancies in Chronic Myeloid Leukemia
Authors: Shah Binay K. , Ghimire Krishna B
Published: October 2019

Abstract 4247

Background:

Development of second primary cancers among CML patients is not well studied. With improvement in CML survival, long term risks of CML, including second cancers need to be evaluated. This study was conducted to evaluate second primary malignancies in CML patients using data from the US Surveillance, Epidemiology and End Results (SEER) cancer registries.

Methods:

We analyzed the Surveillance, Epidemiology, and End Results (SEER*Stat) database: Incidence - SEER 13 Regs Research Data, Nov 2011 Sub, Vintage 2009 Pops (1992–2009) using MP-SIR Session. We compared secondary cancer rate among adult CML patients (older than 20 years of age) during the period 1992 – 2009. We also evaluated the risk of secondary malignancies in pre- (1992–2000) to post- imatinib (2001–2009) eras. We used SEER MP-SIR session and Graph pad scientific software to calculate p value.

Results:

The total number of CML patients older than 20 years of age, reported during 1992–2009 period was 8,511. There were 4286 and 4225 CML patients in the pre- (1992–2000) and post- (2001–2009) Imatinib era respectively. All site secondary cancer (n=475) incidence was significantly higher among CML patients compared to general population with observed/expected ratio (O/E):1.28, p=< 0.05, an absolute excess risk of 31.39 per 10,000.

Similarly, all sites secondary cancer in post-(2001–2009) Imatinib era was significantly higher compared to pre- imatinib era with O/E ratio of 1.50 vs 1.13, p=0.03.

Conclusions:

This study showed that overall risk of second malignancies among CML patients is higher compared to general population. The risk of second primary malignancies is higher in post- imatinib era.

Disclosures:

No relevant conflicts of interest to declare.
Effects of a Histone Deacetylase Inhibitor On Myeloid Leukemia Cell Line with Mixed-Lineage Leukemia Partial Tandem Duplication
Authors: Keino Dai , Hayashi Mutsumi , Ohyama Ryo , Morimoto Mizuho , Kondoh Kensuke , Shimada Akira , Yamada Taketo , Kinoshita Akitoshi
Published: October 2019

Abstract 4331

BACKGROUND:

Mixed lineage leukemia-Partial tandem duplication (MLL-PTD) is one of the MLL gene rearrangements accompanying leukemia, and is associated with a worse prognosis. Since MLL regulates a gene transcription, histone deacetylase inhibitors (HDACi) have been considered to exert antitumor effects through epigenetic modification. We established a leukemia cell line KOPM-88 containing MLL-PTD from a child with acute myeloid leukemia (AML). Non-obese diabetic severe combined immunodeficient (NOD/SCID) mice inoculated with KOPM-88 cells exhibited leukemic infiltrations in the bone marrow and hemiparalysis because of compression myelopathy (Hayashi et al., Br J Haematol, 2007). We therefore investigated the effects of HDACi on KOPM-88 cells and NOD/SCID mice inoculated with KOPM-88 cells.

MATERIALS & METHODS:

The cell lines employed were KOPM-88 and K-562. We chose K-562 as a control because it contains a wild type MLL. Firstly, a HDACi, trichostatin A (TSA), was added with 100 nM/L concentration in KOPM-88 cells for 24 hours and in K-562 cells for 12 hours. Apoptosis was evaluated by using a flow cytometer. MLL-PTD mRNA expression was measured by using a real time PCR before and after incubation with TSA. Secondary, 5×106 of KOPM-88 cells were transplanted in NOD/SCID mice (n=32). Then, TSA was injected intraperitoneally into a half of the transplanted mice three times a week for 5 weeks (TSA group, n=16). DMSO, which was used as a solution of TSA, was injected intraperitoneally into the half rest of mice (control group, n=16). Hemiparalysis was counted as an event. The probability of event-free survival (EFS) and the probability of overall survival (OS) were analyzed using the Kaplan-Meier method.

RESULTS:

TSA significantly increased the apoptosis in KOPM-88 cells (30.03±2.83% vs 53.17±2.11%,p <0.01), but it did not significantly increased the apoptosis in K-562 cells (8.15±0.20% vs 14.04±0.23%,p=0.08). TSA also significantly decreased the level of MLL-PTD mRNA in KOPM-88 cells (1.78±0.35 copies/μgRNA vs 0.38±0.33 copies/μgRNA, p <0.05). The median follow-up of the TSA group was 178 days (range; 30–210), and that of the control group was 149 days (range; 98–210). Although seven months-EFS was significantly better in the TSA group than in the control group (78±0.8% vs 43.8±0.8%,p <0.05), seven months-OS was similar between the TSA group and the control group (43.8±0.8% vs 18.8±0.6%,p=0.25).

CONCLUSIONS:

Our study suggests that HDACi exerts an anti-leukemic effect partly from suppression of MLL-PTD transcription on leukemia cells with MLL-PTD. This anti-leukemic effect of HDACi was also confirmed in vivo mice model. The patients with MLL-PTD leukemia may benefit from HDACi treatment.

Disclosures:

No relevant conflicts of interest to declare.
Treatment of Acute Promyelocytic Leukemia (APL) At Tawam Hospital UAE
Authors: Alam Arif , Narayanan Harimohan , Sonday Shanaaz , Hussain Sabir , Lal Amar , Burney Mohammad , Kristensen Jorgen
Published: October 2019

Abstract 4347

Acute Promyelocytic Leukemia (APL) is a unique sub-type of Acute Myeloid leukemia associated with a balanced reciprocal translocation between chromosomes 15 and 17 and 80% of the cases present with bleeding diathesis caused by severe coagulopathy. The translocation generates a fusion transcript joining the PML(promyelocyte) and RAR-α (retinoic acid receptor-α) genes. The therapy of APL has been revolutionized by the introduction of differentiating agents All Trans Retinoic Acid (ATRA) and Arsenic Trioxide.

All patients were treated as per Pethema protocol. Initially LPA99 (Sanz MA. Blood. 1999 Nov 1;94(9):3015-21) and since January 2012 a risk adapted therapy based on LPA2005 (Sanz MA et al. Blood June 24, 2010 vol. 115 no. 25 5137–5146). Treatment included induction followed by 3 cycles of consolidation and two years of maintenance.

Nineteen patients were diagnosed with APL between January 2009 and June 2012. Three patients are excluded from the analysis as karyotyping and/or PCR did not confirm the diagnosis. The median age was 35 years (range 22–53 years). Male to female ratio was 4:1. Nine (56%) patients were stratified as high risk (WBC ≥ 10 ×109/l) while, seven (44%) as intermediate risk and low risk (WBC < 10 ×109/l). Three (19%) patients had early death despite treatment and supportive care. The cause of death was intracranial hemorrhage (1) pulmonary hemorrhage (1) and multi-organ failure (1). Thirteen patients achieved a complete morphological and molecular remission (80%). There has been only 1 case of treatment failure (high risk at presentation). This patient was successfully re-induced with arsenic trioxide and achieved second molecular complete remission. Unfortunately he relapsed a second time and is currently alive in third morphological remission but remains PCR positive for PML/RARα 33 months after diagnosis.

Our limited experience shows favorable outcome (CR 80%) for the treatment of APL using the Pethema protocol compared to published data (Tallman MS. Blood 2002;99(3):759–767). Early death rate remains high despite intensive supportive care. The only variable is the availability and initiation of ATRA at the clinical suspicion of diagnosis both at the referring hospitals and treatment center.

Disclosures:

No relevant conflicts of interest to declare.