bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preclinical Testing of a Novel Axl-Kinase Inhibitor in Chronic Lymphocytic Leukemia
Authors: Göbel Maria , Möllmann Michael , Görgens Andre , Dührsen Ulrich , Hüttmann Andreas , Giebel Bernd , Unger Anke , Choidas Axel , Dürig Jan 
Published: October 2019

Abstract
Abstract 1799
The receptor tyrosine kinase Axl belongs to the TAM (Tyro-3, Axl and Mer) family and is involved in the progression of several human malignancies including chronic lymphocytic leukemia (CLL), where it is has been found to be overexpressed in comparison to normal B-cells. An increasing body of evidence suggests that Axl acts as an oncogene which increases the survival, proliferation, metastatic potential and chemotherapy resistance of tumor cells. Hence, it has been recently identified as a potential therapeutic target in a wide range of tumor entities with deregulated Axl expression including prostate cancer, glioma, lung cancer and CLL. Here, we investigated two different Axl inhibitors for their potential to inhibit the migratory capacity and survival of leukemic cells in preclinical CLL models.
In vitro studies: Freshly isolated PBMC (>90% CD5+CD19+) from CLL patients were incubated in serum free medium for 48h containing concentrations series of 2 different Axl inhibitors: BMS777607, a previously published inhibitor of the MET kinase family, and LDC2636, a novel inhibitor of the TAM receptor tyrosine kinase (RTK) family with high affinity to Axl. Viability of CLL cells was assessed by trypan blue staining and flow cytometry employing annexin V staining. Since a polarized phenotype is required for migration, cell polarization was analyzed by time-lapse video-microscopy. We detected cytotoxic effects in a patient dependent manner that were more prevalent in LDC2636 as compared to BMS777607 treated cells (LD50= 1.4 μM vs. 5.2 μM, p<0.004, n=5). Cell polarization of the remaining viable cells was significantly reduced in a dose dependent fashion in comparison to vehicle only controls (LDC2636 IC50 = 7.2 μM, p<0.00001; BMS777607: IC50=6.2μM; p=0.0004). Of note, both Axl inhibitors exhibited significantly weaker effects on both, the viability and cell polarization of normal PBMC over the whole concentration range tested (p<0.05, n=5).
In vivo studies: To verify our hypothesis that reduced cell polarization results in decreased homing of leukemic cells in vivo we employed a recently developed adoptive transfer model of CLL. In this model NOD/SCID/gcnull(NSG) mice were pre-treated with a single intraperitoneal bolus of LDC2636 or BMS777607 (20 mg/kg) and subsequently transplanted with primary CLL cells. Both Axl inhibitors significantly reduced the homing capacity of CLL cells to the bone marrow of NSG mice by 43% and 59%, respectively, compared to vehicle treated controls (LDC2636: p=0.046, BMS777607 p=0.0077; n=3).
These data demonstrate that Axl inhibitors exert potent in vitro and in vivo activity against human CLL cells, which is caused at least in part by the suppression of CLL homing to their supportive stromal niches.

Disclosures:
No relevant conflicts of interest to declare.
Myeloid Impairment Contributes to Immunoparesis in Multiple Myeloma but Not MGUS
Authors: Romano Alessandra , Parrinello Nunziatina , Vetro Calogero , La Cava Piera , Chiarenza Annalisa , Conticello Concetta , Palumbo Giuseppe A , Di Raimondo Francesco 
Published: October 2019

Abstract
Abstract 1831

Introduction
In Multiple Myeloma (MM), but not in the monoclonal gammopathy of unknown significance (MGUS), the immune function is impaired as consequence of an immunologically hostile microenvironment and cellular defects, including reduction of immuno-surveillance and T-cell immunoparesis.
We conducted an study focused on the myeloid compartment in MM, and its role in the progression from MGUS to MM.

Methods
Between January 2009 and April 2011 peripheral blood obtained from 60 consecutive newly diagnosed MM and 70 MGUS plus 30 healthy subjects was studied for evaluation of myeloid subpopulations and lymphoid paresis.
Myeloid dysfunction was evaluated as percentage and absolute count of circulating myeloid suppressor cells (MDSC) in peripheral blood assessed by flow cytometry as follows: im-MDSC (CD34+/CD11b+/CD13+/CD14-/ HLA-DR-/CD45+), neutrophilic-like N-MDSC (CD11b+/CD13+/CD15+/CD14-/HLA-DR-/Lin-) and monocytic-like mo-MDSC (CD14+/HLA-DRlow/-).
Myeloid function was evaluated by phagocytic activity using a commercially available kit (Phagotest R).
Further, we investigated whether MM-neutrophils were able to induce anergy in T-cells. Neutrophils isolated from healthy donor (N=6), MGUS (N=3) or MM (N=6) peripheral blood (PB) were co-cultured with T-lymphocytes obtained from healthy donors. Expression of markers of activation in response to stimulation with PHA-P for 2 hours was assessed by flow cytometry as antigen density expressed as normalized mean of fluorescence intensity (N-MFI) of CD71 at 48 hours.

Results
The capability of phagocytosis of in neutrophils and monocytes from MM patients at diagnosis was significantly reduced compared to healthy subjects (p<0.001) and MGUS (p<0.0001). While the mature suppressive N-MDSC subset was not increased in MGUS and MM patients, the mo-MDSC subpopulation showed an increasing trend from healthy donors through MM (p=0.06) and the im-MDSC subset was significantly higher in MM vs healthy (p=0.002) and MGUS (p=0.001).
After PHA-P stimulation, expression of CD71 (a marker of activation) in normal T-lymphocytes was increased (2954 ± 240.6 arbitrary units, au), and it was reduced (751.3 ± 30.48 au, p=0.0001) when co-coltured with MM-neutrophils, while no differences were evident in co-colture with MGUS- (2783 ± 206.1 au, p=0.61) or healthy donors-neutrophils (2588 ± 135.4, p=0.38).

Conclusion
Taken together, our findings suggest that in MM but not in MGUS there is a myeloid cell dysfunction that is correlated to impairment of T- cell arm. These alterations may have a role in the development of MM.

Disclosures:
No relevant conflicts of interest to declare.
Higher Doses of Prophylactic Anticoagulation Is More Effective in Preventing Venous Thromboembolism in Morbidly Obese Inpatients.
Authors: Wang Tzu-Fei , Milligan Paul , Wong Catherine A , Thoelke Mark S , Deal Eli N , Gage Brian F 
Published: October 2019

Abstract
Abstract 2268

Background:
Obesity increases the risk for venous thromboembolism (VTE), and the optimal dose of prophylactic anticoagulation to prevent VTE in morbidly obese inpatients is unknown.

Objectives:
To quantify the efficacy and safety of higher doses of prophylactic heparin or enoxaparin for VTE prevention in morbidly obese inpatients with a body mass index (BMI) ≥ 40 kg/m2and/or weight >100 kg within the BJC HealthCare system.

Patients/Methods:
We analyzed 10,239 inpatients with weight > 100 kg and/or morbid obesity (BMI ≥ 40 kg/m2) discharged from the three major hospitals in the BJC HealthCare system from January 1st, 2010 through February 29th, 2012. We used logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) and Wald's chi-square to compare proportions. The primary efficacy outcome was an ICD-9 diagnosis code for VTE. The primary safety outcome was an ICD-9 diagnosis codes for bleeding.

Results:
On-treatment analysis showed higher doses of prophylactic anticoagulation (heparin 7500 units three times daily instead of 5000 units two or three times daily or enoxaparin 40 mg twice daily instead of 40 mg once daily) halved the risk (OR 0.52, 95% CI 0.27–1.00; p = 0.05) of symptomatic VTE in the 3928 morbidly obese inpatients (weight > 100kg and BMI ≥ 40 kg/m2). The rate of VTE was 1.48% (35/2369) in these morbidly obese inpatients who received standard prophylactic doses of unfractionated heparin or enoxaparin, compared to 0.77% (12/1559) in those who received higher doses, with an absolute risk reduction of 0.71% and a number needed to treat (NNT) of approximately 140. Intention-to-treat analysis failed to show reduction in VTE rate due to low (< 40%) physician compliance in prescribing the higher doses. Increased doses of prophylactic anticoagulation were not associated with bleeding (OR 0.84, 95% CI 0.66–1.07, p = 0.15).

Conclusions:
Higher doses of prophylactic anticoagulation nearly halve the rate of VTE in morbidly obese inpatients (with BMI ≥ 40 kg/m2 and weight > 100 kg), but do not increase bleeding. Given their safety and ease of implementation, higher doses of prophylactic heparin or enoxaparin should be considered in morbidly obese inpatients. Clinicians' compliance and awareness need to be improved to prevent VTE in this vulnerable population.

Disclosures:
No relevant conflicts of interest to declare.
The Role of Interim-PET and Final-PET in the Outcome of Peripheral T-Cell Lymphoma (PTCL) Treated At the Diagnosis with CHOP.
Authors: Pellegrini Cinzia , Casadei Beatrice , Derenzini Enrico , Broccoli Alessandro , Stefoni Vittorio , Gandolfi Letizia , Quirini Federica , Argnani Lisa , Zinzani Pier Luigi 
Published: October 2019

Abstract
Abstract 2721
Role of interim- and final-PET in peripheral T-cell lymphoma (PTCL) is quite unknown. To determine predictive value of PET on overall survival (OS), we evaluated interim-PET (i-PET) and final-PET (f-PET) in PTCL patients treated in first-line with 6 CHOP-21 courses. From September 2003 to July 2010 we diagnosed and treated in our institution 34 advanced stage PTCL patients (15 females and 19 males). The median age at diagnosis was 46 years (range, 21–81 years); 9 patients were in stage III, and 25 in stage IV. According to the histologic subtype there were 11 PTCL-nos, 6 AILT, 9 ALCL Alk+, 6 ALCL Alk-, and 2 NK/T nasal type patients. Four patients had bulky disease; eight patients had bone marrow involvement, 15 patients had 1 extranodal involvement and 10 had more than 2 extranodal sites. All patients underwent initial staging PET/CT; i-PET was performed after 3 cycles of CHOP-21 and the median time from the end of third course to i-PET was 14 days (range, 7– 18 days). f-PET scans were performed 35 days (range, 30– 45 days) after the end of therapy.
The table summarizes the correspondence between i-PET and f-PET results:
N=34 f-PET negative, n (%) f-PET positive, n (%) i-PET negative 27 19 (70.4) 8 (29.6) i-PET positive 7 1 (14.2) 6 (85.8)
With a median follow-up of 71 months (range, 5.8–120.9 months), 17/19 (89.5%) patients with i-PET negative are in continuous CR (CCR) and only 1/7 (14.2%) patient with i-PET positive is still in CCR. Figures show the overall survival (OS) according to response at i-PET and f-PET. In figure 1a we observe OS plotted according to i-PET results: 78.6% for negative patients (solid line) and 21.4% for positive patients (dashed line) at 88.7 months (p=0.02); in figure 1b we observe OS plotted according to f-PET results: 93.7% for negative patients (solid line) and 21.4% for positive patients (dashed line) (p<0.0001).

In conclusion, our results demonstrate that positive i-PET is not predictive of a worse outcome in PTCL. On the contrary, the f-PET seems to represent a significant step forward in the prediction of survival for these patients. Larger and prospective studies and harmonization of PET reading criteria are needed.

Disclosures:
No relevant conflicts of interest to declare.
Impact of Reduced Dose Intensity for Elderly Patients with Diffuse Large B-CELL Lymphoma Receiving R-CHOP Every 14 or 21 Days: An Analysis of the LNH03–6B GELA Study.
Authors: Delarue Richard , Tilly Herve , Salles Gilles , Thieblemont Catherine , Mounier Nicolas , Molina Thierry Jo , Bologna Serge , Haioun Corinne , Bosly Andre 
Published: October 2019

Abstract
Abstract 2723

Introduction:
Elderly patients with diffuse large B-cell lymphoma (DLBCL) frequently receive reduced dose-intensity (DI) chemotherapy (Lyman GH et al. J Clin Oncol 2004) but impact on outcome in the era of classical or dose-dense immunochemotherapy is unknown. Final results of the LNH03–6B did not show any difference in PFS (HR: 0.99 [95%CI: 0.78–1.26]; p=0.90) and OS (HR: 0.96 [95%CI: 0.73–1.26]; p=0.75) between R-CHOP14 and R-CHOP21 (Delarue et al. ASCO 2012).

Methods:
Patients between 60 and 80 years old with DLBCL and aaIPI≥1 were eligible. They were randomized between R-CHOP14 and R-CHOP21 for 8 cycles. Dose-intensity (DI) was calculated for all patients for cyclophosphamide (CPM), doxorubicin (DOX) and rituximab (RTX) and patients were separated into 4 quartiles for each of these drugs. Outcome (PFS and OS) according to final DI was evaluated for all patients and in R-CHOP14 and R-CHOP21 arms.

Results:
602 pts were randomized, 600 were evaluable, 304 with R-CHOP14 and 296 with R-CHOP21. Median age was 70 years. Patient characteristics were similar in both arms. The percentage of cycles administered with G-CSF was 89% in R-CHOP14 and 66% in R-CHOP21. Median interval between 2 cycles was 14 d [9–94] in R-CHOP14 arm and 21 d [15–66] in R-CHOP21 arm. Median dose-intensity was 88% in R-CHOP14 and 97% in R-CHOP21 for CPM, and 88% in R-CHOP14 and 96% for R-CHOP21 for DOX. There was no difference of median dose-intensity for CPM and DOX according to G-CSF use at C1 in R-CHOP14 arm. In the R-CHOP14 arm, the increase of DI at the end of treatment, calculated according to 3-week interval as a reference, was 133% for CPM and DOX. When separating patients in 4 quartiles according to final dose intensity, there was no impact for CPM, DOX and RTX for the entire cohort in term of PFS and OS. Moreover, decreased DI for CPM, DOX and RTX did not impact negatively PFS and OS in patients randomized in the R-CHOP14 arm. On the other hand, for patients included in the R-CHOP21 arm, PFS was negatively impacted by lower DI of CPM (p=0.02), DOX (p=0.007) and RTX (p=0.006). OS was also negatively impacted by lower DI of CPM (p=0.0002), DOX (p<0.00001) and RTX (p<0.0001). In the R-CHOP21 arm, the negative impact was pronouncedly marked when comparing patients in the first and the second quartiles with those in the fourth quartile.

Conclusion:
While low DI has a major impact on PFS and OS in patients who receive conventional dose immunochemotherapy, consequences for patients receiving dose-dense immunochemotherapy seem less pronounced. As a consequence, immunochemotherapy could be safely decreased for elderly patients who receive R-CHOP14 and experienced adverse events.

Disclosures:
No relevant conflicts of interest to declare.
Bendamustin-Rituximab Induction Followed by Observation or Rituximab Maintenance for Newly Diagnosed Patients with Waldenström's Macroglobulinemia: Results From a Prospective, Randomized, Multicenter Study (StiL NHL 7–2008 –MAINTAIN-; ClinicalTrials.gov Identifier: NCT00877214).
Authors: Rummel Mathias J. , Lerchenmüller Christian , Greil Richard , Görner Martin , Hensel Manfred , Engel Erik , Jaeger Ulrich , Breuer Friedhelm , Hertenstein Bernd , Prummer Otto , Buske Christian , Barth Juergen , Burchardt Alexander C. , Brugger Wolfram 
Published: October 2019

Abstract
Abstract 2739

Background:
Bendamustine-rituximab (B-R) has demonstrated substantial efficacy in the primary treatment of indolent lymphomas. A multicenter prospective randomized trial was initiated to investigate the impact of adding rituximab maintenance following B-R first-line induction. The trial included patients (pts) with Waldenström's Macroglobulinemia (WM), marginal zone, small lymphocytic and mantle cell lymphomas. Here we present first and preliminary results for pts with WM.

Methods:
Treatment consisted of a maximum of 6 cycles of B-R (bendamustine 90 mg/m2, rituximab 375 mg/m2) administered every 28 days plus 2 cycles of rituximab every 4 weeks. Responding pts (≥ PR) were eligible for further treatment and were randomized to observation or 2 years of rituximab maintenance every two months. The primary endpoint is PFS.

Results:
From April 2009 to July 2012, 57 centers included a total of 162 pts with newly diagnosed WM with a median age of 67 years (31% < 60 years, 69% > 60 years). At baseline/inclusion/screening, the median values for b2-microglobulin (b2M), hemoglobin and IgM were 3.3 mg/L, 10.1 g/dL and 2110 mg/dL (max. 13400 mg/dL), respectively. To date (Aug 2012) 116 pts are evaluable for response (43 women [37%] and 73 men [63%]). 100 pts have responded to B-R leading to an overall response rate (ORR) of 86%. At the time of response evaluation, the median Hb was 12.6 g/dl and the median IgM was 380 mg/dl.
90 pts have undergone randomization to date, 43 to observation and 47 to maintenance. Randomization is ongoing. No results can be reported from that ongoing part of the trial. No uncommon toxicities were observed during B-R induction.

Conclusion:
Initial results of our trial confirm that for patients with Waldenström's macroglobulinemia, treatment with B-R is an efficacious treatment with a manageable safety profile. The role of rituximab maintenance in this disease is under investigation.

Disclosures:
No relevant conflicts of interest to declare.
Essential Role of the Transcription Factor ZBP-89 in Lymphopoiesis
Authors: Woo Andrew J. , Huang Hui , Piers Taylor , Cantor Alan B 
Published: October 2019

Abstract
Abstract 277
We previously identified the Krüppel-type zinc finger transcription factor ZBP-89 (also called zfp148) as a novel GATA1 associated protein in erythroid and megakaryocytic cells. ZBP-89 also associates with other GATA family members such as GATA2 and GATA3, Friend of GATA (FOG) cofactors, and RUNX1. It is ubiquitously expressed, but has high-level expression in a subset of tissues including thymus, spleen, bone marrow, lung and brain. Our prior studies using morpholino knockdown in zebrafish, in vitro differentiation and chimeric mouse analysis of ZBP-89 genetrap embryonic stem cells, and lentiviral shRNA knock down in primary human CD34+ cells demonstrated a functional role for ZBP-89 in erythroid and megakaryocyte maturation. In this study, we generated conditional knock out mice to further examine the requirements for ZBP-89 in vivo. On a mixed strain background, full ZBP-89 knock out mice were born at close to Mendelian ratios. However, the ZBP-89−/− mice were severely runted and had increased mortality over the first 30 days of life. Surviving pups had significant growth failure, but eventually matched their wild type and heterozygous littermates by about 6 weeks of age. Analysis of erythroid maturation in bone marrow and spleen using flow cytometry for CD71 and Ter119 demonstrated impaired erythroid maturation in a ZBP-89 allele-dose dependent manner. On a pure C57BL/6 genetic background, nearly 100% of the ZBP-89−/− mice died within the first 10 days of life from unclear causes. ZBP-89fl/fl, Mx1-Cre mice developed lymphopenia and platelet abnormalities following activation of Cre by polyI-polyC injection. The lymphopenia was due to reduction in both B and T cells. Further delineation of the T-cell defect using ZBP-89fl/fl, Lck-Cre mice demonstrated impaired maturation of double negative (CD4−CD8−) T cells at the DN3 (CD25+ CD44−) to DN4 (CD25−CD44−) stages in thymi from 5–6 week old mice. These findings indicate that ZBP-89 plays functional roles in multiple hematopoietic lineages. Moreover, they identify ZBP-89 as a novel transcriptional regulator of lymphocyte development. We speculate that this latter role involves its known interactions with GATA3, FOG-1, and/or RUNX1, which are all similarly involved in lymphopoiesis. We also show that the ZBP-89 family member ZBP-99 is highly expressed in thymus and other hematopoietic tissues, and may therefore play partially overlapping roles with ZBP-89.

Disclosures:
No relevant conflicts of interest to declare.
CTCF Mediated Enhancer and Promoter Interaction Regulates Differential Expression of TAL1 Oncogene in Normal and Malignant Hematopoiesis
Authors: Patel Bhavita , Deng Changwang , Litt Michael , Riberio Mariana St. Just , Cui Kairong , Kang Yuanyuan , Qiu Yi , Zhao Keji , Huang Suming 
Published: October 2019

Abstract
Abstract 281
The key hematopoietic transcription factor TAL1/SCL is essential for the specification of hematopoietic stem cells (HSCs) and differentiation along myeloid and erythroid lineages. However, ectopic activation of TAL1 gene is the most frequent gain-of-function mutation associated with childhood T-cell acute lymphoblastic leukemia (T-ALL) in approximately 60% of patients. To understand underlying epigenetic mechanisms of TAL1 activation in normal and in malignant hematopoiesis, we performed ChIP, ChIP-seq, and chromatin conformation capture assays to investigate chromatin structure profile which correlates with transcriptional activation, at the TAL1 locus comparing erythroid progenitors, K562 and CD36+ cells, with T-ALL cells, Jurkat and Rex cells. We found distinct epigenetic landscape and chromatin organization across the TAL1 locus in these two different types of hematopoietic cells. Although H3K4me3 is enriched at the TAL1 promoter in both erythroid progenitors and in T-ALL cells, the erythroid specific +51 enhancer is marked by active histone modifications only in erythroid progenitors, but not in T-ALL cells. Furthermore, we demonstrated that +51 enhancer interacts with the TAL1 promoter 1a via a long range chromatin loop in vivo in erythroid CD36+ and K562 cells. The recruitment of hSET1 HMT complex facilitates this enhancer/promoter chromatin interaction and depletion of hSET1 leads to loss of H3K4 methylation, enhancer/promoter interaction, RNA PolII loading, and TAL1 transcription at both the TAL1 promoter 1a and the +51 enhancer. In addition, loss of SET1 in CD34+ HSCs exhibited a significant reduction in the formation of CFU-E and BFU-E colonies. In contrast, neither H3K4 methylation nor enhancer/promoter interaction was detected at the +51 enhancer in T-ALL cells. Finally, we investigated the role of insulator protein CTCF in the regulation of TAL1 expression in normal and in malignant cells. We found that regardless of similar CTCF binding patterns at the TAL1 locus in erythroid progenitors and T-ALL cells, CTCF elements flanking the TAL1 locus mediate a long-range loop that encloses TAL1 promoter and enhancer in the same chromatin domain in erythroid progenitors, whereas in T-ALL Jurkat cells the CTCF site located between the promoter 1a and the +51 enhancer forms a repressive loop that expels the +51 enhancer from the same domain with the promoter 1a. Overall, our study demonstrates that a novel long range intrachromosomal interaction between the TAL1 promoter 1a and the +51 enhancer regulated and organized by hSET1 histone methyltransferase and insulator protein CTCF controls TAL1 promoter activity in normal versus malignant hematopoiesis.

Disclosures:
No relevant conflicts of interest to declare.