bluuebunny/crossref_metadata_2025 huggingface dataset:
Lig4 R278H Mutation Impacts on LT-HSC Functions, Cancer Development and Aging
Authors: Yan Catherine T. , Park Ji hye , Muniandy Parames , Troppito Logan , Welner Robert
Published: October 2019

Abstract 1350

DNA Ligase IV (Lig4) is an essential component of the non-homologous end-joining (NHEJ) repair pathway, essential for the end-ligation of broken DNA ends generated during V(D)J recombination and IgH Class Switch Recombination (CSR) in B lymphocytes. Mutations in Lig4 underlie the DNA Lig4 Syndrome, a rare herited immunodeficiency disease. We have modeled one such mutation in mice, a homozygous arginine to histidine 278 (R278H) change with the enzyme active site, which others and we have shown significantly impairs the catalytic end-ligation activity of the LigIV protein. These mice show significant immune-specific defects, including decreased T and B lymphocytes, in part associated with defects in development, increased cell death, and/or autophagy. Bypass of B lymphocyte development leads to increased numbers of total peripheral B lymphocytes that can undergo robust CSR at near normal levels, which however contain high levels of IgH specific DNA breaks and translocations. Both young and older mice display significant reduction in LT-HSCs, which may underlie their B and T lymphocyte associated defects, which in LT-HSC reconstitution experiments in SCID mice, fail to engraft. The decreased R278H mice LT-HSCs observed are in contrast to previous reported findings for Ku80 and DNA-PKcs deficient mice, and also ATM deficiency, which we further are investigating to elucidate the normal and pathological functions of aberrant Lig4. We hypothesize the cause of the LT-HSC defects to be caused by changes in DNA damage, cell cycle checkpoint responses and genomic stability maintenance associated with the R278H mutation, that promote the restriction or selection of LT-HSC cell populations that are prone to genomic instability during differentiation. As such, the majority of relatively, young adult R278H mice routinely spontaneously develop T cell lymphomas, and mice that do not succumb to lymphomas subsequently go on to develop other solid tumors and other pathological consequences which are characteristic of premature aging. Our findings implicate Lig4 is required for genomic stability maintenance and proliferative expansion of earliest HSCs and other stem cell populations. The implications of our findings in the context of impacts of the R278H mutation on genomic instability and DNA damage response in the context of HSCs, cancer development and aging in the DNA Lig4 Syndrome, and its relation to other human immunodeficiency and progeroid syndromes will be discussed.

Disclosures:

No relevant conflicts of interest to declare.
Signal Transducer and Activator of Transcription 3 Promotes Leukemogenesis
Authors: Ghoshal Sampa , Brady Michael T , Ustwani Omar , Tracy Erin , Den Haese Jason , Wallace Paul K. , Baumann Heinz , Wetzler Meir
Published: October 2019

Abstract 1395

We have previously shown that constitutive activation of the signal transducer and activator of transcription (STAT) 3 protein is associated with worse outcome in patients with acute myeloid leukemia (AML). To clarify the role of STAT3 signaling in AML leukemogenesis, STAT3 shRNAmirs were introduced into the AML cell line HEL that carries the Janus kinase 2 with V617F mutation leading to constitutive tyrosine phosphorylation and activation of STAT3 and STAT5. Clonal line of HEL cells expressing STAT3 shRNAmir or control shRNA were generated and then transduced with a lentiviral virus harboring a constitutively expressed firefly luciferase gene. Engraftment of these cells was evaluated in a disseminated xenograft non-obese diabetic severe immunocompromised mouse model. When tested in vitro, HEL STAT3 knock-down (HEL-STAT3KD) cells showed normal STAT5 expression and activity but had lower proliferation rates than control cells, PKC-bII and Pim1 were down-regulated, and activation of ERK1/2 was increased. Trans-signaling by hyper-IL-6 enhanced STAT3 phosphorylation proportional to STAT3 level. In vivo imaging of luciferase activity demonstrated significant delay in engraftment of STAT3KD cells compared with controls (Figure). To the best of our knowledge, this is the first demonstration that STAT3 knockdown delays leukemia cell engraftment, that STAT3 signaling is crucial for AML leukemogenesis and should promote STAT3-tailored therapeutic targeting.Figure:Down-regulating STAT3 results in delayed HEL engraftment. Panel 1A, Optical CCD images of HEL (non-silenced control in the upper panel and shRNAmir in the lower panel) xenografts in NOD/SCID mice from day 28 and day 45. Panel 1B, Graphs showing correlation of luciferase gene expression in HEL xenografts (p=0.0079, Man-Whitney test). The graphs were generated from repeated scanning of the mice on days 14, 28, 35, 45, 53 and 72. Individual mean values (photons/s/cm2/sr) calculated from the regions of interest were plotted.Figure:. Down-regulating STAT3 results in delayed HEL engraftment. Panel 1A, Optical CCD images of HEL (non-silenced control in the upper panel and shRNAmir in the lower panel) xenografts in NOD/SCID mice from day 28 and day 45. Panel 1B, Graphs showing correlation of luciferase gene expression in HEL xenografts (p=0.0079, Man-Whitney test). The graphs were generated from repeated scanning of the mice on days 14, 28, 35, 45, 53 and 72. Individual mean values (photons/s/cm2/sr) calculated from the regions of interest were plotted.

Disclosures:

No relevant conflicts of interest to declare.
CCDC26 Polymorphisms Are Differentially Expressed in Myeloid Malignancies with Mutant IDH1 Compared to Their IDH2R140-Mutated or IDH-Unmutated Counterparts
Authors: Lasho Terra L , Tefferi Ayalew , Pardanani Animesh , Finke Christy , Fink Stephanie R , Decker Paul A , Jenkins Robert
Published: October 2019

Abstract 2807

CCDC26 is a retinoic acid-dependent modulator of myeloid cell differentiation and death (Yin W et al. Oncogene 2006 :25 :3735). CCDC26 maps to chromosome 8q24.21 and germline polymorphisms in the gene have been associated with low-grade gliomas (Jenkins RB et al. Cancer Genetics 2011;204 :13), which in turn have recently been shown to frequently express IDH1 mutations (Parsons D et al, Science 2008;321 :1807). More recently, we have discovered that CCDC26 SNP associations in gliomas are primarily restricted to patients with IDH1 mutations (Jenkins et al. unpublished observations). We therefore hypothesized that germline CCDC26 SNPS might be associated with patients with myeloid malignancies that harbor IDH1 mutations (Mardis et al. NEJM 2009;361 :1058). Seventy-two IDH -mutated patients with chronic or blast phase myeloproliferative neoplasms (MPN), myelodysplastic syndromes or acute myeloid leukemia (most constituting post-MPN events) were identified: 18 IDH1 R132, one IDH2 R172 and 53 IDH2 R140. These 72 patients and a control group of 153 IDH unmutated cases with myeloproliferative or myelodysplastic neoplasms (total n =225) were genotyped for CCDC26 risk alleles associated with IDH -mutated gliomas: rs10464870, rs891835 and rs4295627. The respective minor allele frequencies (MAF) were significantly different between IDH1 (11%, 8% and 6%) and IDH2 (30%, 27% and 24%) mutated cases (p=0.037, 0.040 and 0.021; OR 3.4, 3.7 and 6.1 with 95% CI of 1.1–10.5, 1.1–13.0 and 1.3–28.9) as well as between IDH- wild type (24%, 24% and 21%) and IDH1 -mutated (11%, 8% and 6%) cases (p=0.10, 0.043 and 0.035; OR 0.42, 0.29 and 0.21 with 95% CI of 0.15–1.19, 0.09–0.96 and 0.05–0.90). The MAF values in our IDH -unmutated cases were similar to that of population-based controls. However, the direction of SNP associations in IDH1 -mutated myeloid malignancies were opposite of those seen in IDH1 -mutated gliomas. Our observations suggest a differential effect of CCDC26 genetic polymorphisms in IDH1 -mutated myeloid malignancies compared to either their IDH2 R140-mutated or IDH1 -mutated gliomas. Such differences in genomic context might contribute to hitherto seen differences in prognostic impact between IDH2 R140 vs. IDH1 R132 vs. IDH2 R172, in AML (Green CL et al. Blood Published online before print May 19, 2011, doi: 10.1182/blood-2010-12-322479).

Disclosures:

No relevant conflicts of interest to declare.
Dicer Plays An Important Role in the Progression and Prognosis of Chronic Lymphocytic Leukemia
Authors: Xu Wei , Zhu Dan-Xia , Fan Lei , Fang Cheng , Zou Zhi-Jian , Wang Yin-Hua , Li Jian-Yong
Published: October 2019

Abstract 2848

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the western world. Alterations in microRNAs (miRNAs) expression have been proposed to play role in CLL pathogenesis. However, the reasons of miRNAs expression alterations observed in CLL have not been elucidated, one possible explanation suggested is deterioration of miRNA biogenesis machinery involves Dicer and Drosha. Dicer and Drosha are main regulators of miRNA biogenesis, and deregulation of their expressions have been observed in various cancers including breast cancer, ovarian cancer, prostate cancer, neuroblastoma tumors, et al. To investigate the role of Dicer and Drosha in CLL, we assessed the expression of Dicer and Drosha and their correlation with other prognostic factors, including Binet stages, immunoglobulin heavy chain variable gene (IGHV) mutation status, TP53 mutation status, ZAP-70 protein and CD38 expression level in 165 CLL patients by using real-time PCR methods. We found that Dicer expression was significantly higher in patients of Binet B and C stage compared with Binet A stage (mean ± SD, 0.017 ± 0.010 vs. 0.015 ± 0.019; p =0.001). Patients with unmutated IGHV genes had significant lower expression of dicer than patients with IGHV mutations (mean ± SD, 0.012± 0.006 vs 0.019± 0.013, p <0.0001). The lower expression level of Dicer was also significantly associated with higher level of CD38 and ZAP-70 (p =0.0304 and p =0.0075, respectively). We also analyzed Dicer expression in different cytogenetic subgroups. Lower Dicer level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22.3) in contrast to higher level in good risk cytogenetics (deletion in 13q14 as the sole abnormality). Furthermore, the lower expression of Dicer in CLL shows a strong association with shorter overall survival (OS) (132 months vs. not reached, p =0.0046) as well as with reduced treatment free survival (TFS) (24 months vs.110 months, p =0.0006). By contrast, no differences in the expression of Drosha among these groups of patients were observed. Our data have been able to demonstrate for the first time that Dicer expression may play an important role in the progression and prognosis of CLL.

Disclosures:

No relevant conflicts of interest to declare.
Adoptively Transferred Central Memory Derived Human CD8+Effectors Exhibit Superior Engraftment Fitness Over Their Naïve T Cell Derived Counterparts
Authors: Wang Xiuli , Wong ChingLam W , Aguilar Brenda , Chang Wen-Chung , Ostberg Julie R , Riddell Stanley R. , Forman Stephen J. , Jensen Michael C.
Published: October 2019

Abstract 2982

In clinical trials of adoptive T cell therapy, the persistence of transferred cells correlates with therapeutic efficacy. The engraftment fitness of ex vivo propagated T cells is in part pre-determined by the differentiation status of precursor T cells from which effector cell products are derived. In peripheral blood, T cells are comprised of three major subsets- naïve, central memory (Tcm) and effector memory (Tem), each having distinct phenotypic and functional attributes. We have previously shown that human CD8+ effector cells derived from Tcm were superior to Tem in their ability to engraft and persist following adoptive transfer (Wang, X. 2011). In this study, we set out to compare the engraftment fitness of CD8+ effector cells derived from naïve precursors with that of Tcm-derived effectors. FACS sorted CD8+ CD45RA+CD62L+ naïve (Tn) and CD8+CD45RO+CD62L+ Tcm cells from healthy donors were expanded in vitro for 14 days in the presence of OKT3, feeder PBMC and IL-2 at 50U/mL. Despite the comparable levels of CD28 expression on unstimulated CD8+ Tn and CD8+Tcm (91±2% for CD8+Naive and 94±2% for CD8+Tcm), Tcm-derived effector T cells (CD8+TCM/E) displayed significantly higher levels of CD28 expression with corresponding high levels of cytoplasmic phosphorylated-AKT as compared to Tn-derived cells (CD8+TN/E) (47±5% for CD8+TN/E vs. 83±4% for CD8+ TCM/E). After the initial 14 days of in vitro expansion, CD8+TCM/E were able to persist in vitro for more than 50 days in the presence of gamma-c cytokines (IL-2 50/ml or IL-15 10ng/ml) while CD8+TN/E failed to survive in either condition, which is consistent with the observed higher expression levels of IL-15R α and IL-2R β by CD8+TCM/E. After engraftment in huIL-15 replete immunodeficient (NSG) mice, we observed that CD8+TCM/E exhibited higher levels engraftment and mounted more robust proliferative responses to in vivo challenge with immunostimulatory vaccines. In contrast to CD8+TN/E, engrafted CD8+TCM/E reaquired/sustained high frequency of cells expressing IL-7Ralpha. To re-direct T cell specificity against B-lymphoid malignancies, purified CD8+Tn and CD8+Tcm from healthy donors were engineered with lentiviral vector encoding CD19R-CD28-EGFRt-epHIV7. CD19-specific CD8+TCM/E persist after adoptive transfer into the human IL15 reconstituted NSG mice, whereas no engraftment was detected in the CD19-specific CD8+TN/E infused NSG mice. These studies using human T cells support the use of central memory derived effector cells for adoptive therapy of cancer and infectious disease.

Disclosures:

No relevant conflicts of interest to declare.
Whole Genome Sequencing Reveals a Widely Expressed Mutation (MYD88 L265P) with Oncogenic Activity in Waldenstrom's Macroglobulinemia
Authors: Treon Steven P , Xu Lian , Zhou Yangsheng , Liu Xia , Yang Guang , Cao Yang , Hanzis Christina , Sheehy Patricia , Manning Robert , Patterson Christopher J , Laramie Jason M , Skifter Donald A , Lincoln Stephen E , Hunter Zachary
Published: October 2019

Abstract 300

We performed whole genome sequencing (WGS) of lymphoplasmacytic cells from 30 Waldenstrom's Macroglobulinemia (WM) patients, with paired normal tissue sequencing for 10 patients. Tumor and normal genomes were both sequenced to an average of 66X coverage of mapped individual reads. A recurring sequence variant at position 38182641 in chromosome 3p22.2 was identified which resulted in a single nucleotide change from T®C in the myeloid differentiation primary response (MYD88) gene, and a predicted non-synonymous change at amino acid position 265 from leucine to proline (L265P). This variant was the most common of a median of 3,419 (range 2,540–4,011) somatic variants identified by WGS in paired patients, and was present in tumor cells from all 10 paired patients, and 16 of 20 unpaired patients. For 22 of 26 patients, the MYD88 L265P variant was heterozygous, whereas in 4 patients an acquired UPD event at 3p22.2 resulted in homozygous presence of the variant in at least a subset of tumor cells. Sanger sequencing confirmed the presence of the MYD88 L265P variant in all 26 patient tumor samples revealed by WGS, as well as in one additional patient's tumor sample that was not identified by the variant calling algorithms but for whom 12% of the WGS read level mappings showed the MYD88 L265P variant. In contrast, the MYD88 L265P variant was absent in normal paired tissues. Sanger sequencing therefore confirmed the somatic presence of the MYD88 L265P variant in tumor cells from 27 of 30 (90%) WM patients, and also identified this variant in BCWM.1 and MWCL-1 WM cells. In contrast, the MYD88 L265P variant was absent in CD138+ selected tumor cells from 8 of 8 multiple myeloma (MM) patients, and CD19+ cells from 12 of 12 healthy individuals, as well as in 7 of 8 patients with IgM monoclonal gammopathy of unknown significance (MGUS), in whom absence of the MYD88 L265P variant was further confirmed by TA cloning and sequencing of at least 100 clones. In the sole IgM MGUS patient in whom the MYD88 L265P mutation was detected, subsequent disease evolution occurred. Importantly, knock-down of MYD88 expression by lentiviral transduction led to loss of NF-κβ signaling and apoptosis of both BCWM.1 and MWCL-1 WM cells, with enhanced survival observed by complementary transduction with MYD88 L265P versus MYD88 wild type. The results of these studies therefore demonstrate a widely expressed somatic variant (MYD88 L265P) in malignant LPC of WM, whose presence confers oncogenic activity, and which may help distinguish WM disease from IgM MGUS or MM.

Disclosures:

No relevant conflicts of interest to declare.
A Sequence Variation in the Promoter Region of PTPN22 Gene Predicts Relapse After HLA-Fully-Matched Unrelated Bone Marrow Transplantation for Hematologic Malignancies
Authors: Espinoza Luis J. , Takami Akiyoshi , Nakata Katsuya , Onizuka Makoto , Morishima Yasuo , Fukuda Takahiro , Kodera Yoshihisa , Nakao Shinji
Published: October 2019

Abstract 3088

The protein tyrosine phosphatase non-receptor 22 (PTPN22), also known as LYP, is an intracellular phosphatase ubiquitously expressed with particularly high expression in hematopoietic tissues that is a critical negative regulator of signaling through the T cell receptor and has emerged as the strongest common genetic risk factor for human autoimmunity outside the major histocompatibility complex. In this study we analyzed the impact of the polymorphism rs2488457 (1123G>C) in the promoter region of PTPN22 gene on transplant outcomes in patients undergoing unrelated HLA-matched bone marrow transplantation (BMT) through the Japan Donor Marrow Program. The PTPN22 rs2488457 genotypes were retrospectively analyzed in a cohort of 663 patients with hematologic malignancies and their unrelated donors. The presence of the C/C or C/G genotype in the donor side was associated with a significantly lower incidence of relapse compared to the donor G/G genotype (28% vs. 34% 5-years, P =0.05) (Fig.1). No difference was noted in transplant-related mortality, or graft-versus-host disease in relation to the rs2488457 polymorphism. The donor C/C or C/G genotype remained statistically significant for relapse in the multivariate analyses (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.43 to 0.85; P =0.004). These differences in relapse did not significantly affect on overall survival (OS) (48% vs. 49% 5-years, P =0.85). The recipient PTPN22 genotypes did not significantly influence the transplant outcomes. These results suggest an association of the donor C/C or C/G genotype with lower disease relapse. These could therefore be useful in selecting the donor and creating therapeutic strategies for improving the final outcome of allogeneic BMT.

Disclosures:

No relevant conflicts of interest to declare.
Comorbidities Influence Survival in Patients with Multiple Myeloma
Authors: Wildes Tanya , Vij Ravi , Colditz Graham A
Published: October 2019

Abstract 3142

Introduction:

Advancing age is associated with poorer prognosis in patients with multiple myeloma (MM). Comorbidities increase in prevalence with age, but the impact of comorbidities on survival in patients with MM is not known. The purpose of this study was to examine the impact of comorbidities on survival in multiple myeloma. Methods: All patients (pts) with MM diagnosed and treated at Washington University School of Medicine in St. Louis, Missouri from 1999–2010 were identified from the Barnes-Jewish Hospital Oncology Data Services Database. The institution's cancer registrars retrospectively collect clinical, demographic and survival data in accordance with the American College of Surgeons Commission on Cancer guidelines. Comorbidities are graded as None, Mild, Moderate or Severe using the ACE-27 comorbidity index [Piccirillo et al. J Reg Mgmt 1999]. Patients without data on comorbidities were excluded from the study. The primary endpoint was overall survival (OS), calculated from the date of diagnosis and censored at the time of last follow-up. OS was estimated using the Kaplan-Meier method, and compared between comorbidity groups using the Log-Rank test. The independent effects of age and comorbidities were evaluated using Cox Proportional Hazards Modeling. Results: 569 patients were identified in the database. Median age of patients was 59 years (range 33–91 years); 54.8% were male, 45.2% were female; 74.9% were white, 23.2% were black, and 1.9% were other races/ethnicities. Based on the ACE-27 comorbidity index, 181 pts (31.8%) had no comorbid medical conditions, 226 (39.7%) had mild comorbidities, 115 (20.2%) had moderate comorbidities, 47 (8.3%) had severe comorbidities. In the entire cohort, the median OS was 49.2 months [95% confidence intervals (CI) 42.9 – 55.6 months]. Survival by comorbidity category and age group are shown in table 1. The differences in survival between comorbidity groups in each age group and the entire cohort were statistically significant (log-rank p<0.001). Severe comorbidities were associated with a significantly increased risk of death after controlling for age (HR 1.97, P=0.002). Conclusion: The presence and severity of comorbidities confer a poorer prognosis in patients with MM. Further study is needed to determine to what extent comorbidities directly impact survival versus impacting therapeutic decision-making and tolerance of therapy.

Disclosures:

Vij: Celgene: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau.
Venous Thrombotic Events (VTEs) in Acute Myeloid Leukemia (AML) Patients During Induction Therapy (IT): Identifying Risk Factors, and Safety of Using Anticoagulation Therapy
Authors: Muslimani Alaa , Rifai Aya , Chisti Mohammad Muhsin , Ashkar Ayham , Muslemani Kinda , Margolis Jeffery , Nadeau Laura , Ye Hong , Micale Mark , Huang James , Jaiyesimi Ishmael
Published: October 2019

Abstract 3148

Background:

VTEs are common complications in association with IT which may cause additional morbidity and mortality in AML patients. However, treating patients with AML is challenging because of the cytopenias due to chemotherapy and the high risk for bleeding during IT. This study investigates frequency, risk factors, and safety of using anticoagulation (AC) therapy for VTEs during IT.

Method:

We retrospectively reviewed the charts of AML patients who received IT between January, 2000-January, 2011 at William Beaumont Health Systems. Exclusion criteria included a documented personal history of inherited thrombophilia. Data retrieved included the following: patient characteristics, leukemia subtype, cytogenetic risk, location of the VTEs, FLT3 mutations, IT regimen used (cytarabine and anthracycline regimens or hypomethylating agents), AC therapy, bleeding complications, mortality related to AC therapy. All patients who received AC were initially treated with regular intravenous unfractionated heparin or subcutaneous low molecular weight heparin. Patients were subsequently started on oral warfarin during the first 10 days of the initial treatment with a targeted INR of 2.0–3.0.

Results:

We found 48 of 363 (13.2%) AML patients developed VTEs during IT. Of those patients, 56.3 % were female. The VTEs occurred most frequently in upper extremities (58%) and were catheter-related. Other locations for VTEs included lower extremities (21%), pulmonary embolism (15%), and mesenteric or portal veins (6%). We note that 41 patients (87%) received AC therapy. Of these, three patients (7.3%) had bleeding complications and no AC therapy-related deaths were observed.

When the three cytogenetic risk groups were compared, there was no difference in the incidence of VTEs (good vs intermediate vs poor). Patients with FLT 3 mutations, however, had a significant higher incidence of VTEs when compared to patients without FLT3 mutations (55.3% vs 12% p <0.001). Finally, patients treated with cytarabine + anthracycline regimen had a higher incidence of VTEs compared to patients treated with hypomethylating agents (81.3% vs 4.2 % p <0.001.)

Conclusions:

We found that 13% of AML patients developed VTEs during IT, most commonly in upper extremities and were catheter-related. The risk for VTEs was markedly increased in patients with FLT3 mutations. Furthermore, using a cytarabine + anthracycline regimens carried a higher risk for VTEs when compared to regimens using a hypomethylating agents. Finally, using AC therapy during IT is relatively safe and is associated with low risk of bleeding complications.

Disclosures:

No relevant conflicts of interest to declare.
Absolute Lymphocyte Count As Predictor of Overall Survival for Patients with Multiple Myeloma Treated with Single Autologous Stem Cell Transplant: Experience of a Single Centre,
Authors: Jimenez-Zepeda Victor H , Reece Donna E. , Trudel Suzanne , Chen Christine , Franke Norman , Winter Andrew , Tiedemann Rodger E. , Kukreti Vishal
Published: October 2019

Abstract 4121

Post-Autologous stem cell transplant (ASCT) studies have demonstrated that early absolute lymphocyte count (ALC) recovery is associated with prolonged survival in some hematological malignancies. Peripheral blood lymphocytes from Multiple Myeloma (MM) were shown to have direct anti-MM activity by proliferative and cytotoxic responses to autologous and allogeneic myeloma plasma cells

Disclosures:

Jimenez-Zepeda: J & J: Honoraria. Reece:Bristol, Meyers, Squibb: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Johnson&Johnson: Research Funding; Merck: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Millennium: Research Funding; Amgen: Honoraria. Chen:Celgene Corporation: Consultancy, Honoraria, Research Funding. Kukreti:Celgene: Honoraria.
A Retrospective Analysis of 344 Fludarabine Melphalan RIC Allogeneic Stem Cell Transplants for Myeloid and Lymphoid Malignancies In Australia and New Zealand 1998–2008,
Authors: Bryant Adam J , Pillai Elango , Kennedy Glen , Kalff Anna , Ritchie David , George Biju , Hertzberg Mark , Patil Sushrut S. , Spencer Andrew , Fay Keith , Cannell Paul , Berkahn Leanne , Doocey Richard , Spearling Ruth , Nivison-Smith Ian , Moore John
Published: October 2019

Abstract 4143

AIM:

Fludarabine Melphalan (FluMel) is the commonest Reduced Intensity Conditioning (RIC) regimen used in Australia and New Zealand. This study aims to assess the relative benefit of this regimen in both lymphoid and myeloid malignancies and to further delineate risk factors associated with an improved survival using RIC conditioning.

METHOD:

This was an ABMTRR based retrospective study assessing the outcome of FluMel RIC allografting in 9 Australian and New Zealand Centres between 1998 and 2008. Data was collected from centres using an excel based eCRF emailed to centres. Analysis was performed using Stata software and a p value less than 0.05 was considered significant.

RESULTS:

Median follow up was 3.4 years. There were 342 patients with a median age of 54 years (18–68) and 61% were male. 234 patients had myeloid malignancies with AML (n=166) being the commonest indication whereas there were 110 lymphoid patients with NHL (n=64) the main indication. TRM at D100 was 14% with no significant difference between the groups. OS and DFS were similar between myeloid and lymphoid patients (50% and 43% at 5 years respectively). There was no difference in the cumulative incidence of relapse and GVHD between the groups. Multivariate analysis revealed 4 adverse risk factors for DFS: non-HLA identical sibling donor, not in remission at transplant, previous autologous transplant, and recipient CMV +ve. The presence of Chronic GVHD was associated with a better DFS predominantly due to a marked reduction in relapse (HR 0.44, p=0.003).

CONCLUSION:

This is one of the largest analyses of Fludarabine Melphalan RIC transpants performed. This dataset confirms that FluMel provides durable remissions in both myeloid and lymphoid malignancies with 50% overall survival at 5 years. The multivariate analysis provides important clues for improving outcomes when planning FluMel conditioning in patients with haematological malignancies.

Disclosures:

No relevant conflicts of interest to declare.
Targeting CXCR4 with Cell-Penetrating Pepducins Enhances Survival in Disseminated Lymphoma
Authors: Covic Lidija , O’Callaghan Katie M , Ngyen Nga , Mo-Ying Hsieh , Klein Andreas K. , Sprague Kellie , Van Etten Richard A. , Kuliopulos Athan
Published: October 2019

Abstract 4244

The G-protein coupled receptor, CXCR4, which normally regulates interactions between stroma and hematopoietic stem cells in the bone marrow, is highly expressed on a variety of malignant hematological cells, such as lymphoma and lymphocytic leukemia cells. A new treatment concept has arisen that CXCR4 may be an effective therapeutic target as an adjunct to standard clinical treatments of hematologic malignancies. In this study we developed novel cell-penetrating lipopeptide antagonists of CXCR4, called pepducins, to interdict signaling to intracellular G-proteins in response to the CXCR4 ligand, SDF-1. We demonstrated that pepducins targeting the first (i1) or third (i3) intracellular loop of CXCR4 completely abrogated SDF-1-mediated chemotaxis of lymphocytic leukemia and lymphoma cell lines, as well as primary cells isolated from patients with chronic lymphocytic leukemia. Pepducins enhanced apoptotic cell death in lymphoma and primary leukemia cells when used in combination with the CD20-targeted antibody, rituximab. Furthermore, pepducin treatment significantly increased survival both as monotherapy and in combination with rituximab in mice with disseminated lymphoma. Together, these data demonstrate that CXCR4/SDF-1 signaling is effectively inhibited by cell-penetrating pepducins, suggesting that these lipopeptide antagonists may represent a potentially new treatment strategy for lymphoid malignancies.

Disclosures:

No relevant conflicts of interest to declare.
Azacitidine for the Treatment of Acute Erythroleukemia: Three Case Reports
Authors: Pierdomenico Francesca , Almeida Antonio
Published: October 2019

Abstract 4285

Acute erythroleukemia (AEL) is usually characterized by cytopenias with myelodysplastic features and is frequently associated with unfavourable karyotype. AEL is associated with a poor prognosis. There is no specific therapy for AEL and results of standard induction chemotherapy have been unsatisfactory. Hypomethylating agents have been used with success in myelodysplastic syndromes (MDS) with improved overall survival (OS) of MDS patients treated with azacitidine compared to those receiving conventional care regimens in the AZA001 phase III trial. Efficacy of hypomethylating agents has also been demonstrated in small groups of AEL patients, advocating a role for these agents alone, or in combination, as first line therapy. We report 3 patients diagnosed with AEL at a single institution treated with azacitidine 500 mg/m2 every 4 weeks divided in 5 days per cycle. All cases were diagnosed according to the 2008 WHO criteria and response criteria were based on the revised recommendation of the International Working Group published in 2003.Table 1.Patients demographic characteristics.PatientAgea (in years)SexCo-morbidities162MObesityBenign prostatic hyperplasia265MNone376MDiabetesTable 2.Patients hematological characteristics at baseline.PatientHemoglobin(g/dL)WBC(x109/L)/ANCPlatelets (x109/L)Cytogenetic18.01.700/0.47060000del(5)(q15q?(31)27.710.300/1.300367000Normal karyotype36.81.000/0.18012400045, XY, -7, del(20)(q11q13)Table 3.Treatment characteristics and response.PatientPrevious treatmentsTreatment durationTime to transfusion independencyBest Hematological responseTime to response1Conventional chemotherapy13 cycles4 cyclesComplete remission (no cytogenetic remission)6 cycles2None17 cycles5 cyclesComplete remission10 cycles3None9 cycles4 cyclesHematological improvement4 cycles

Therapy was well tolerated and all patients achieved transfusion independency with improvement in quality of life. At 12 months follow-up, all of them are alive, two patients are in complete sustained remission, one of whom awaits stem cell transplantation, while one patient is currently on supportive care.

These results confirm the active role of azacitidine in AEL.

Disclosures:

Almeida: Celgene: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; BMS: Speakers Bureau.
Use of All Trans Retnoic Acid (ATRA) Via Nasogastric Tube (NGT) in Patients Unable to Swallow in Treatment of Acute Promyelocytic Leukemia (APL): A Case Series
Authors: Preet Mohan , Sidhu Gurinder , Khillan Rajnish , Silbergleit Marc , Braverman Albert S. , Khillan Ratesh
Published: October 2019

Abstract 4300

Introduction:

ATRA is the critical component of treatment of APL, and when used in combination with anthracycline chemotherapy can induce remission in over 90% of patients. At initial presentation, patients are at high risk for bleeding or disseminated intravascular coagulation, which may be exacerbated by immediate chemotherapy. Except in patients with marked leukocytosis, ATRA should precede chemotherapy. ATRA is available as 10 mg capsules and should be ingested orally and not crushed. The capsules cannot, therefore, be used in patients unable to swallow, or administered by NGT.

Patients and Methods:

We present two APL cases where patients unable to swallow and acutely bleeding, received ATRA via NGT. ATRA capsules were opened, the free powder aspirated into a glass syringe, and the remaining capsule contents suspended in soy bean oil and aspirated into the same syringe (Shaw, 1995).

Case 1:

A 33-year-old female with juvenile onset diabetes and blindness presented with fever vaginal bleeding and coma with response only to painful stimuli. Her white blood count (WBC) was 0.5 k/MicroL with 27% bands, 20% lymphocytes and 10% promyelocytes; platelets were 18 K and PT/PTT was 14.7/33. Bone marrow (BM) was replaced by cells with granular cytoplasm and bilobed nuclei. PML-RARa was not detected by cytogenetics and fluorescent in situ hybridization (FISH), but was by PCR. Daunorubicin was administered and the ATRA oil suspension was given on 14 successive days. Hematologic recovery had occurred by day 16, PCR was negative for PML-RARa by 20, and following consolidation she remains in complete hematologic and cytogenetic remission after 7 months. MRI revealed white matter changes but after IV-HGG she regained consciousness.

Case 2:

A 66-year-old man with coronary artery disease presented with fever, rectal bleeding and pulmonary hemorrhage, which required intubation and mechanical ventilation. WBC was 7.9 with 3% bands, 19% lymphocytes and 22% promyelocytes. Platelet count was 13 and PT/PTT was 9.6/23.6. BM confirmed APL, with FISH positive for PML- RARa. He was started on ATRA oil suspension via NG tube and daunorubicin. By day 27 FISH was PML-RARa negative, but he continued to require ventilatory support for 3 weeks and succumbed to pneumonia and septic shock.

Conclusion:

In two patients unable to swallow and bleeding, ATRA administration as an oil suspension via NGT was safe and effective, inducing cytogenetic remission in both. IV liposomal ATRA is not FDA approved and no other parenteral formulation is available.

Disclosures:

No relevant conflicts of interest to declare.
Indications for Platelet Transfusions: How Educational Interventions Can Improve Compliance with National Guidelines
Authors: Katz Elena , Klek Malgorzata , Graham Robert E , Levine Randy L.
Published: October 2019

Abstract 4331

Intro:

Evidence-based guidelines are developed and promoted to help physicians implement best practice care. The American Society of Hematology (ASH) platelet transfusion guidelines changed in 2007 to a prophylactic transfusion threshold of 10, 000/μL from the previous 20,000/μL. We conducted a retrospective analysis at a metropolitan teaching hospital to assess how well physicians are complying with the new professional guidelines as well as the older, less stringent criteria to administer platelet transfusions. We then assessed the effect of an educational intervention on transfusion practices.

Methods:

All patients receiving platelet transfusions over a five-month period from Jan-Feb, and April-June 2010, admitted to the medical, critical care and cardiac services were reviewed. The medical record clinical indication was then evaluated against the ASH 2007 “Evidence-Based Platelet Transfusion Guidelines” (Slichter SJ. Hematology 2007): bleeding and platelets ≤50, 000/μL, pre-invasive procedure and platelets ≤50, 000/μL, prophylactic transfusion for platelets ≤10, 000/μL and WHO bleeding grade ≥ 2. We also assessed how the patients’ clinical indication met the previous prophylactic threshold for platelet transfusion of ≤20, 000/μL laid forth by the landmark study by Gaydos LA. et. al. (The quantitative relation between platelet count and hemorrhage in patients with acute leukemia. N Engl J Med 1962).

Following initial data collection, we implemented an educational intervention by giving a lecture, reviewing all indications for platelet transfusions, and distributing a pocket card to the house-staff on the medical wards in August, 2010. We subsequently gathered post-intervention data following the methods described above for four consecutive months from Sept-December, 2011.

Results:

Eighty-six patients on the selected units received a total of 241 platelet transfusions. Fifty nine percent of the time the patient's clinical indication failed to meet the currently accepted 2007 ASH guidelines and 37% of cases failed to meet even the older guideline.

Eighty-one patients received a total of 237 platelet transfusions post-intervention. Forty-seven percent of the time the patient's clinical indication failed to meet the currently accepted 2007 ASH guidelines and 19% of cases failed to meet the older guideline.

Conclusions:

Based on the significant difference observed between the pre- and post-educational intervention groups, our initial study shows that updating physicians on current evidence-based guidelines for platelet transfusions is a simple and effective means to improve transfusion practices. Periodic educational interventions may prove to even further enhance physician compliance with up-to-date guidelines and we plan to implement additional educational interventions throughout the upcoming academic year.

Disclosures:

No relevant conflicts of interest to declare.
Chronic Myeloid Leukemia Developing in a Patient with B-Cell Chronic Lymphocytic Leukemia – a Case Report
Authors: Zawilska Krystyna M , Malendowicz-Portala Lucyna
Published: October 2019

Abstract 4421

The coexistence of B-cell chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML) in the same patient is rare. A 61-year-old man developed a lymphocytosis with morphologic and immunophenotypic feature of B-CLL (stage I according to the modified Rai classification), without indications for treatment. Ten months later he presented with a markedly elevated leukocytes count and splenomegaly. Myeloblasts, promyelocytes, myelocytes and metamyelocytes appeared in his peripheral blood. A bone marrow aspirate was hypercellular with an increased proportion of the myeloid series in all maturative stages; the percentage of lymphocytes was 3%. The immunophenotypic study demonstrated the typical feature of chronic phase of CML, simultaneously 2% of CD5+ CD19+ cells have been found. Unstimulated bone marrow culture shoved a 46,XY,t(9;22)(q34;q11.2) karyotype, and interphase FISH detected the presence of BCR/ABL fusion with 4,55×106 of p 210 and 1,55×103of p 190 copies/ml. Previously it has been shown that these two different hematological malignancies derive from distinct progenitors.

Disclosures:

No relevant conflicts of interest to declare.
Quantitative Assessment of WT1 Gene Transcript After Hematopoietic Stem Cell Transplantation Is a Powerful MRD Marker to Predict the Clinical Outcome in Acute Leukemia
Authors: Zhao Bingrui , Tang XiaoWen , Cen Jiannong , Jin Song , Shi Xiaolan , Wei Xiaoai , Chang Huirong , Sun Aining , Depei Wu
Published: October 2019

Abstract 4461

Background

WT1 is a panleukemic marker that is expressed in 90% of acute leukemias and has been used as MRD marker after chemotherapy or transplantation. However, the threshold of WT1 to predict relapse and outcome in acute leukemia (AL) patients post transplantation has not been well studied.

Objective

We evaluated the predictive value of quantitative Wilms’ tumor gene (WTl) assessment for relapse following hematopoietic stem cell transplantation (HSCT) in patients of AL.

Methods

The quantitative assessment of WT1 expression by real-time quantitative PCR (RQ-PCR) was measured in 63 AL patients (pts) with 326 bone marrow samples at the different time points post transplant. ROC (Receiver Operating Characteristic) curve was used to determine the WT1 threshold in order to predict clinical relapses. Furthermore, AL patients were divided into WT1 positive and negative groups according to the threshold of WT1, and the clinical outcomes of these patients post transplant were analysed retrospectively.

Results

BM samples from 19 pts who relapsed post transplanted showed significantly higher WT1 expression levels compared to the samples from 44 pts in remission (P<0.01), with a median expression level of 1270 (range 55–47596) and 132 (range 0–2959) copies WT1/104ABL, respectively. Ten of 18 relapsed patients died from recurrence, and had higher levels of WT1 expression than that of other 8 patients. Based on the ROC curve, the cut-off value of WT1 was 585 copies WT1/104ABL, dividing 63 patients into WT1-positive group (>585,n=21) and the negative group (≤585,n=42). The WT1-negative group had longer relapse- free survival (RFS) (P<0.01) and overall survival (OS) (P<0.01) than that of positive group.

Conclusion

Our data suggest that, in the HSCT setting, the sequential and quantitative analysis of WT1 may be useful as a leukemia marker for monitoring MRD, and predicting AL relapse post transplant.

Disclosures:

No relevant conflicts of interest to declare.
R-CHOP in the Treatment of EBV-Diffuse Large B-Cell Lymphoma of the Elderly
Authors: Beltran Brady E , Alva Jose C , Morales Domingo , Quinones Pilar , Castillo Jorge J
Published: October 2019

Abstract 4988

Introduction:

Epstein Barr virus-positive diffuse large B-cell lymphoma (EBV+ DLBCL) of the elderly is a new entity considered in the most recent WHO classification. It is a very aggressive entity associated with a short survival. The role of rituximab-containing regimens in EBV+ DLBCL of the elderly is currently unknown.

Methods:

Between January 2002 and December 2010, 22 patients diagnosed with EBV+ DLBCL of the elderly were selected for this study, from which 11 patients received cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) and 11 patients received rituximab and CHOP (R-CHOP). Both groups received chemotherapy at every 3 weeks cycles. Clinical data were reviewed retrospectively and patient's biopsies were analyzed for the immunohistochemical expression of bcl-6, CD10, CD30 and MUM-1/IRF4. Samples were also analyzed for the presence of EBV-encoded RNA (EBER) using an in situ hybridization (ISH) technique. Chi-square and Mann-Whitney tests were used to compare categorical and continuous variables, respectively. Overall survival (OS) estimates were calculated using the Kaplan-Meier method and compared using the log-rank test. P-values <0.05 were considered statistically significant.

Results:

The median age was 73 years (range: 49–85 years) with a male predominance (2.7:1). Eleven patients (50%) had advanced clinical stage (i.e. stage 3 and 4), nine patients (45%) had elevated LDH levels, eleven (50%) had performance status ECOG >1 and 13 (59%) had high or high-intermediate IPI scores. Fourteen out of 17 patients studied (82%) had a non-germinal center DLBCL. When comparing the CHOP and R-CHOP groups, there was no statistical difference in median age (p=0.87), sex distribution (p=0.63), stage distribution (p=0.28), IPI scores (p=0.15), Oyama scores (p=0.23), ECOG performance status (p=0.39), LDH levels (p=0.62), lymphocyte counts (p=0.06), hemoglobin levels (p=0.20), platelet counts (p=0.14), Ki67 expression by malignant cells (p=0.57) and proportion of patients with a non-germinal center profile (p=0.91). Additionally, there was no statistical difference in overall response and complete response rates (p=0.66). When evaluating median OS, patients treated with CHOP and R-CHOP had median OS at 5 and 20 months, respectively (p=0.04).

Conclusion:

Based on the results of this retrospective study, patients with EBV+ DLBCL of the elderly had a short OS when treated with CHOP alone; however, R-CHOP seems to confer a survival advantage in patients with EBV+ DLBCL of the elderly, although it seems shorter than in EBV-negative DLBCL patients.

Disclosures:

Castillo: GlaxoSmithKline: Research Funding; Millennium Pharmaceuticals: Research Funding.
Ex Vivo Expansion of SCID Leukemia-Initiating Cells Using NANEX Nanofiber Scaffold
Authors: Fischer Stephen L , Zhao Yukang , Qu Cheng-Kui , Sakthivel Ramasamy
Published: October 2019

Abstract 4994

The concept of the leukemic stem cell (LSC) has gained wide acceptance since it was first definitively established using a NOD-SCID xenotransplantation model nearly 15 years ago. LSCs, which are functionally defined as SCID leukemia-initiating cells (SL-ICs), are believed to possess biological properties that render them resistant to conventional chemotherapy. Although there is still much debate over how to phenotypically define LSCs, there is general agreement that LSCs are rare in acute myeloid leukemia (AML), which has hindered efforts to develop LSC-targeted therapies. In order to provide researchers and pharmaceutical companies with an ample supply of LSCs for testing, methods are needed to generate large numbers of LSCs from patient samples.

Ex vivo expansion of LSCs in culture is one approach that offers tremendous promise for increasing cell numbers for research and drug development. Conditions that enable efficient expansion of normal hematopoietic stem cells (HSCs) can be used as a starting point for developing an optimal culture system for LSCs. The natural bone marrow microenvironment maintains HSCs in close contact with a complex network of stromal cells and extracellular matrix, likely indicating that cell-cell and cell-matrix interactions play an important role in maintaining their stem cell phenotype. With the goal of mimicking the bone marrow stem cell niche, Arteriocyte, Inc. has developed a 3-D NANEX nanofiber based cell culture substrate. The NANEX substrate is designed to provide topographical and substrate-immobilized biochemical cues that act in synergy with media additives to enhance HSC proliferation.

Here, we present our recent work with the NANEX platform towards achieving a high yield ex vivo expansion of LSCs. Using common LSC markers, including CD34, CD38, CD117, and CD123, we quantify and characterize NANEX-expanded leukemic cells using flow cytometry. We compare NANEX to standard tissue culture polystyrene and demonstrate that NANEXÔ significantly improves LSC expansion and reduces clonogenic phenotype loss during ex vivo culture. Additionally, we show that NANEXÔ-expanded cells engraft in NOD-SCID mice and, through limiting dilution analysis, quantify the increase in SL-ICs as a result of culture on NANEXÔ. Our data indicates that NANEX technology provides a robust ex vivo expansion of SL-ICs and, with further development, offers great potential for use in LSC-targeted drug development.

Disclosures:

No relevant conflicts of interest to declare.