bluuebunny/crossref_metadata_2025 huggingface dataset:
Psi Domain of b3 Integrin Has Endogenous Thiol Isomerase Function and Is a Potential New Target for Anti-Thrombotic Therapy
Authors: Zhu Guangheng , Chen Pingguo , Reheman Adili , Li June , Ni Heyu
Published: October 2019

Abstract 382

Background:

Platelets are critical for maintaining hemostasis, but inappropriate platelet activation can lead to pathogenic thrombosis. Integrin aIIbb3, the most abundant protein on the platelet surface, is a key molecule for platelet aggregation and thrombus formation. The PSI domain of b3 integrin is highly conserved among different species but the function of the PSI domain in the integrin family has not been well defined and the role of this domain in hemostasis and thrombosis is poorly understood. It has been reported that b3 integrin possess PDI activity, which may play a role in integrin activation and platelet aggregation. However, whether the PSI domain of b3 integrin has PDI function is currently unknown.

Methods:

We generated recombinant protein of PSI domain of mouse b3 integrin. Mouse anti-mouse PSI domain mAbs were generated utilising b3 gene deficient mice (b3−/−) immunized with the recombinant protein. Antibody specificity was determined by flow cytometry and western blot. PDI activity assay of mouse PSI domain and native human b3 integrin was performed using reduced and denatured RNase (rdRNase). The effects of the mAbs on platelet function were measured in vitro using aggregometry and in vivo using intravital microscopy thrombosis model.

Results:

Analysis of the PSI domain of b3 integrin reveals that it contains two CXXC amino acid sequences (the active site motif of PDI), which are highly conserved in different species. Refolding of rdRNase assay showed that the PSI recombinant protein has endogenous PDI activity. Bacitracin, a well-known PDI inhibitor, inhibited PSI domain PDI function in a dose dependent manner. Four anti-PSI domain monoclonal antibodies (mAbs) were generated and showed different inhibitory effects on PDI function of the recombinant PSI domain and purified human platelet b3 integrin. In vitro and ex-vivo studies showed that anti-PSI antibodies inhibited mouse and human platelet aggregation. Using intravital microscopy we demonstrated that anti-PSI mAbs inhibited mouse platelet aggregation and thrombus formation in laser injury thrombosis model.

Conclusions:

To the best of our knowledge, this is the first time in which it has been demonstrated that the PSI domain of b3 integrin has endogenous PDI activity, which may play important roles in cell biology of platelets and other cells. Our data suggest that the PSI domain of b3 may be a new target in controlling platelet function and our mAbs may have potential in anti-thrombotic therapy.

Disclosures:

No relevant conflicts of interest to declare.
PIM Kinase Inhibitors Interfere with the Protective CLL Microenvironment by Blocking CXCR4 Surface Expression and Function
Authors: Decker Sarah , Finter Johannes , Zirlik Katja , Veelken Hendrik , Dierks Christine
Published: October 2019

Abstract 3867

Introduction:

CXCR4 surface expression is strongly elevated on CLL cells and is important for CLL cell survival and homing to the bone marrow. PIM kinases are overexpressed and mutated in various hematologic malignancies including B-cell lymphomas. Recent findings in AML suggest a direct link in between PIM1 kinase expression and the surface expression level of the CXCR4 receptor and Ser339 phosphorylation in CXCR4. Therefore the aim of the presented study was to investigate the role of PIM kinases in regulating the CXCR4-CXCL12 pathway in CLL.

Results:

By using a phospho-CXCR4 Ser339 antibody for both, western blot analysis of CLL cells from the peripheral blood (n=11) and IHC staining of bone marrow from CLL patients (n=30), we can show that in contrast to normal B-cells the majority of CLL cells have a hyperphosphorylated CXCR4 receptor. Furthermore high phosphorylation levels of the CXCR4 receptor in the bone marrow correlated with poor prognosis in CLL. Besides increased phosphorylation of the CXCR4 receptor, also the 3 PIM kinases, especially PIM1 (P=.0060) and PIM2 (P=.0404) are strongly overexpressed in CLL compared to normal B-lymphocytes on mRNA- and protein level. Transcript levels of PIM1 (P=.0020), PIM2 (P=.0006) and PIM3 (P=.0206) positively correlated with the median CXCR4 surface expression. Furthermore PIM1 protein expression demonstrated a positive correlation with the CXCR4 phosphorylation on Ser339. PIM kinase inhibition with 3 different PIM kinase inhibitors (K00135, K00486 and CMV-05–144–01) resulted in a dose-dependent induction of apoptosis in primary human CLL cells independent of the presence of stromal cells, indicating that pathways activated by stromal cells are directly targeted by PIM kinase inhibitors. Additionally, inhibition of PIM with the inhibitor K00135 induced dephosphorylation of the CXCR4 receptor on Ser339 and resulted in enhanced ligand-dependent CXCR4 internalization and reduced reexternalization after withdrawal of CXCL12. Furthermore PIM inhibition induced degradation of internalized CXCR4 receptor and blocked CXCR4 function regarding survival, ERK-phosphorylation and migration towards a CXCL12 gradient. We could further demonstrate that pretreatment of primary CLL cells with PIM kinase inhibitors and resulting down regulation of the CXCR4 receptor strongly reduced homing of CLL cells towards the bone marrow (P=.0293) and the spleen (P=.0104) of Rag2−/−γc−/− mice in vivo.

Conclusion:

Our results demonstrate, that PIM kinase inhibitors are an effective treatment option for CLL by directly inducing pro-apoptotic pathways in CLL cells, but also by blocking the CXCR4 pathway which is important for the interaction of CLL cells with their protective microenvironment.

Disclosures:

No relevant conflicts of interest to declare.
Relation Between Cereblon Expression and Survival in Patients with Newly Diagnosed Multiple Myeloma Treated with Thalidomide
Authors: Broyl Annemiek , Kuiper Rowan , van Duin Mark , van der Holt Bronno , el Jarari Laila , Bertsch Uta , Zweegman Sonja , Buijs Arjan , Hose Dirk , Lokhorst Henk , Goldschmidt Hartmut , Sonneveld Pieter
Published: October 2019

Abstract 3973

Introduction:

Cereblon (CRBN) expression has been described to be essential for the activity of Thalidomide and Lenalidomide. This suggests that presence and possibly increased level of CRBN expression would be associated with better outcome in Thalidomide/Lenalidomide treated patients. The aim of this study was to evaluate CRBN expression in relation to outcome in patients receiving Thalidomide maintenance.

Patients and methods:

The HOVON-65/GMMG-HD4 trial is a multi-center, phase III trial, comparing Bortezomib in induction and post-intensification vs. conventional chemotherapy and daily Thalidomide 50 mg for 2 years post-intensification in newly diagnosed MM patients. This trial demonstrated that Bortezomib during induction and maintenance improved CR and achieved superior PFS and OS (Sonneveld et al., JCO, July 16, 2012). Gene expression profiling was performed at the start of the trial by Affymetrix U133 Plus 2.0 GeneChip, and was available for 96 patients which started Thalidomide maintenance. CRBN expression levels were based on a combined value of probe sets 218142_s_at and 222533_at. CRBN expression was validated using real-time PCR. All survival analyses were performed in SPSS, with survival time taken from the start of maintenance.

Results:

In patients receiving Thalidomide maintenance, increased CRBN expression was significantly associated with longer progression free survival (p=0.005, hazard ratio = 0.7) and longer overall survival (p=0.04, hazard ratio= 0.7). Using Kaplan-Meier analysis for visualization and using the median expression to define high and low expression, a significant separation was found for PFS (Log rank p=0.009) but not for OS (Log rank p=0.13). No association was observed between CRBN expression and PFS/OS after Bortezomib maintenance (PFS, p=0.4, hazard ratio=1.1; OS, p=0.7, hazard ratio=1.1). Multivariate Cox regression analysis was performed using the covariates ISS, CRBN and high-risk cytogenetics, defined as having del(17p) and/or 1q gain and/or t(4;14). Higher CRBN levels remained significantly related to longer PFS (hazard ratio 0.7, p=0.03), but not OS (hazard ratio of 0.8, p=0.3). High-risk cytogenetics and ISS were both significant in both PFS and OS multivariate models, with hazard ratios of 2.8 and 3.6, for high-risk cytogenetics and 2.5 and 5.5, for ISS stage 3, respectively (p=0.0004, p=0.003, high-risk cytogenetics and p=0.01 and p=0.005, ISS stage 3, respectively).

Conclusion:

These data suggest use of CRBN as a biomarker for thalidomide outcome, but further analysis in other Thalidomide trials is required to validate this finding.

Disclosures:

Lokhorst: Genmab: Consultancy. Sonneveld:Onyx: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; celgene: Honoraria, Research Funding.
DNA Copy Number Changes Have Gene Dosage Effects with Consequent Impact On Disease Biology and Prognosis in Multiple Myeloma
Authors: Samur Mehmet Kemal , Shah Parantu K , Wang Xujun , Huang Norman , Minvielle Stephane , Florence Magrangeas , Avet-Loiseau Herve , Munshi Nikhil C. , Li Cheng
Published: October 2019

Abstract 3984

Copy number alterations, deletions and amplifications, are very frequent in multiple myeloma (MM), however, it is less clear how these alterations affect gene expression. We performed a genome-wide analysis of 170 newly-diagnosed uniformly treated MM patients using high-density SNP arrays and Exon ST 1.0 gene expression arrays, and evaluated how copy number alterations affect gene expression in MM. Using SNP array data just over 40% patients had hyperdiploid MM (HMM) while the rest had non-hyperdiploid MM (N-HMM). We used two-step procedure to identify dosage effect scores of genes. At first, for each gene, percentage of copy number altered samples was calculated. Then for each gene percentage of samples that had dosage effect was calculated. Finally dosage effect score for each gene was calculated as a ratio of dosage effect samples percentage to copy number alteration sample percentage. We show that dosage effect in MM is wide-spread and some chromosomal locations are affected by dosage effect more compared to other locations. The dosage effect tracks can be observed at trisomy chromosomes and chromosome 1q, but most explicitly at chromosome 9, 11, 15 and 19. Also for deleted genes, dosage effect can be mostly observed at chromosome 13 and 16q. Separate analysis of HMM and N-HMM patients also showed that HMM patients have higher dosage effect especially in chromosome 15 compared to the others. In addition, relation between dosage effect and gene expression analysis show that the highly expressed genes have significantly higher dosage effect compared to the lowly expressed genes. Also function enrichment analysis showed that genes involved with crucial biological processes including translation, RNA processing and transcription factor genes are enriched in genes with higher dosage effect. Interstingly, dosage resistant genes are enriched in cell death and GTPase processes. These results help us understand the impact of aneuploidy in MM on global gene expression changes. In conclusion, our analysis identifies concordant and discordant gene expression changes associated with DNA copy number alterations, identifying genes and pathways that may play an important role in myeloma disease behavior as well as prognosis.

Disclosures:

No relevant conflicts of interest to declare.
Diagnostic and Prognostic Implications of Spine Magnetic Resonance Imaging At Diagnosis in Patients with Multiple Myeloma
Authors: Song Ik-Chan , Lee Kyu-Seop , Ryu Hae-Won , Lee Myung-Won , Lee Hyo-Jin , Yun Hwan-Jung , Kwon Soon-Tae , Kim Samyong , Jo Deog-Yeon
Published: October 2019

Abstract 3999

The role of baseline spine magnetic resonance imaging (MRI) in patients with multiple myeloma who have no related symptoms or signs is controversial. In the present study, we prospectively evaluated the diagnostic and prognostic implications of whole-spine MRI taken at the time of diagnosis in patients with multiple myeloma.

Patients who were newly diagnosed with multiple myeloma between 2004 and 2011 at Chungnam National University Hospital were enrolled. Abnormal MRI findings that were not detected in plain radiographs were analyzed and categorized as pathological fractures or extramedullary extension of the plasmacytoma. The bone marrow (BM) infiltration patterns on MRI were classified into five categories: homogenous diffuse, micronodular, macronodular, mixed, and normal appearance of the BM. The prognostic implications of the additional lesions found on MRI and the BM infiltration patterns were analyzed.

A total of 113 patients with a median age of 65 (range, 40μ–μ89) years were enrolled in the study. Pathological fractures that were not detected in the bone survey were found in 26 (23.0%) patients, including three (2.6%) patients with no related symptoms or signs. Extramedullary extension of the plasmacytoma was detected in 22 (19.5%) patients, including 15 (13.3%) with epidural extension of the tumor. Of these 22 patients, 11 (50.0%) had no relevant symptoms or signs. Neither the additional pathological fractures nor the extramedullary extensions found correlated with the international staging system stage (ISS). The presence of pathological fractures did not influence overall survival, whereas extramedullary extension of the plasmacytoma was associated with poor overall survival in multivariate analysis (HR 3.205; 95% CI, 1.430 – 9.845; P=0.042). Of the 113 patients, 35 (31.0%) had a diffuse infiltrative pattern, 39 (34.5%) had a micronodular pattern, 15 (13.3%) had a macronodular pattern, 17 (15.0%) had the mixed type, and 7 (6.2%) appeared normal. The BM infiltration patterns did not correlate with the ISS. During follow-up for a median of 21 (range 1 – 91) months, the overall survival of patients with the mixed type (median 24.0 months; 95% CI, 22.9 – 25.1) was shorter compared to those with other patterns (median 56 months; 95% CI, 48.9 – 63.1) (P=0.030). Survival differences were not found among the other patterns.

In summary, baseline spine MRI reveals not only bone lesions, but also extramedullary extension of plasmacytoma that cannot be detected in plain radiographs, even in patients with no relevant symptoms or signs. In addition, the mixed infiltration pattern on MRI is a predictor of poor overall survival. These results indicate that spine MRI should be included in the initial diagnostic investigations for patients with multiple myeloma.

Disclosures:

No relevant conflicts of interest to declare.
Serum Levels of B-Cell Maturation Antigen Are Elevated in Multiple Myeloma Patients and Correlate with Disease Status and Overall Survival
Authors: Sanchez Eric , Li Mingjie , Kitto Alex , Li Jennifer , Wang Cathy S , Rauch Danielle , Delijani Kevin , DeCorso Kevin , Prajogi Andrew , Chen Haiming , Berenson James R.
Published: October 2019

Abstract 4026

Background:

B cell maturation antigen (BCMA) is a receptor whose expression increases during B-cell development and is found on malignant cells from multiple myeloma (MM) patients; however, it has not been identified in human serum.

Methods:

Following informed consent (Western IRB BIO 001), serum was isolated from MM patients and analyzed with a BCMA enzyme-linked immunosorbent assay. Values represent the mean of triplicate experiments. Our human MM xenograft (LAGκ-2) was grown in SCID mice, and animals were treated with bortezomib (BORT) and cyclophosphamide (CY); tumor volume and BCMA levels were determined. Statistical significance of differences observed was determined using a Student's t test and analysis was determined using GraphPad prism software.

Results:

The serum BCMA levels from newly diagnosed MM patients (n = 58) was much higher (13.26 ng/ml) than among age-matched healthy subjects (n = 45; median 2.57 ng/ml; P < 0.0001) and MGUS subjects (n = 25; median 4.43 ng/ml; P = 0.002). Notably, protein levels were much higher among patients with relapsed or refractory disease (n = 88; median 18.99 ng/ml) compared to those with responsive (> partial response) disease (n = 95; median 3.48 ng/ml; P = 0.0016). Following treatment, patients with responsive disease showed decreases in BCMA levels whereas those with progressive disease showed increases. Additionally, with a median follow-up of 8 months (range, < 0 – 83 months), MM patients (n = 193) with BCMA levels above the median (8.43 ng/ml) showed a shortened survival compared to those with amounts below the median concentration (P < 0.0001). Following treatment with BORT and CY, we also showed a marked decrease in tumor volume and serum human BCMA levels in mice bearing the MM LAGκ-2 xenograft whereas untreated animals showed marked increases in tumor size and serum BCMA.

Conclusions:

This is the first report identifying serum BCMA in any human disease and suggests that these levels may be a novel biomarker for monitoring disease status and therapeutic response in MM patients.

Disclosures:

No relevant conflicts of interest to declare.
Casein Kinase II Modulates Topoisomerase II Alpha Nuclear Export and Drug Sensitivity in Multiple Myeloma
Authors: Turner Joel G , Dawson Jana L , Sullivan Daniel M
Published: October 2019

Abstract 4032

Nuclear export of topoisomerase II alpha (topo IIα) to the cytoplasm results in de novo resistance to topo IIα inhibitors in hematological malignancies. We have previously demonstrated that topo IIα is exported from the nucleus of human multiple myeloma cells by a CRM1-dependent mechanism at densities similar to those in myeloma patient bone marrow (Engel et al, Exp. Cell Res. 295:421-31, 2004). We have also identified the nuclear export signals for topo IIα at amino acids 1017–1028 and 1054–1066 using mutated full-length FLAG-topo IIα protein and immunofluorescence microscopy, (Turner et al, J. Cell Sci. 117:3061-71, 2004). In addition, blocking nuclear export with a CRM1 inhibitor or by using CRM1-siRNA sensitizes myeloma cells to topo II poisons (Turner et al. Cancer Res. 69:6899-905, 2009). Therefore, preventing nuclear export may sensitize myeloma cells to topo II inhibitors.

To determine what signals CRM1-mediated nuclear export of topo IIα we investigated the phosphorylation status of topo IIα, both in the nucleus and in the cytoplasm, using proteomic technologies. Topo IIα was isolated from the nuclei and cytoplasm of human myeloma cells by immunoprecipitation. Purified topo IIα fractions were analyzed by Orbitrap mass spectroscopy. We found that serine 1524 was highly phosphorylated in the cytoplasmic fraction. Using site-directed mutagenesis we converted serine 1524 to an alanine to determine if mutated FLAG-tagged topo IIα export was reduced as compared to wild-type FLAG-tagged topo IIα. Serine 1524 is a CK2 phosphorylation site, therefore, we tested a recently published and highly specific inhibitor of CK2; CX-4945 (Ferguson et al, FEBS Letters 585:104–110, 2011). This drug was used in combination with the topo IIα inhibitor doxorubicin and assayed for apoptosis by caspase 3 cleavage and flow cytometry both in vitro using myeloma cell lines and ex vivo using patient bone marrow mononuclear cells.

Using mass spectroscopy we found that cytoplasmic but not nuclear topo IIα was phosphorylated at serine 1524, a published CK2 motif. Using site-directed mutagenesis we converted serine 1524 to an alanine and found that mutated FLAG-topo IIα export was reduced, as compared to wild-type FLAG- topo IIα. The CK2 inhibitor CX-4945 induced apoptosis in both myeloma cell lines and in myeloma patient bone marrow aspirates. In addition, we found that CX-4945 prevented nuclear export of topo IIα in high-density cells. These data were duplicated using a CK2 specific siRNA to knockdown CK2 expression (90% knockdown). Blocking nuclear export of topo IIα with the CK2 inhibitor CX-4945 or CK2-specific siRNA sensitized drug-resistant myeloma cells to the topo II poison doxorubicin. These data may have potential clinical implications in the treatment of multiple myeloma.

Disclosures:

No relevant conflicts of interest to declare.
Comparison of Outcomes Between Unrelated Donor and Sibling Donor Transplant in Adult Patients with Severe Aplastic Anemia: A Single Center Retrospective Study
Authors: Lee Sung-Eun , Yoon Jae-Ho , Shin Seung-Hwan , Yahng Seung-Ah , Cho Byung-Sik , Eom Ki-Sung , Kim Yoo-Jin , Lee Seok , Min Chang-Ki , Kim Hee-je , Cho Seok-Goo , Kim Dong-Wook , Min Woo-Sung , Park Chong-Won , Lee Jong Wook
Published: October 2019

Abstract 4151

For the patient with severe aplastic anemia (SAA) who do not have a sibling donor and had failed to immunosuppressive therapy, allogeneic stem cell transplantation (SCT) from an unrelated donor is therapeutic option. Although unrelated SCT (u-SCT) has shown less favorable outcomes, there were few studies comparing unrelated donor to sibling donor transplant. The aim of the present study was to evaluate the feasibility of u-SCT in adult SAA patients compared with sibling SCT (s-SCT).

This study examined 157 consecutive patients who underwent allogeneic SCT at our institution between April 2001 and December 2011. In this study, for a homogenous cohort, patients who received second allogeneic SCT were excluded. The diagnosis of acute GVHD or chronic GVHD was made as the NIH published consensus criteria.

There were 71 male and 86 female patients with a median age of 31 years (range, 13–59 years). The median interval from the diagnosis to transplantation was 24 months (range; 1–346 months). The median transfusions prior to SCT were 47 units (range; 4–680 units). Patients with SAA (n=114) or VSAA (n=43) had received SCT from sibling donor (n=82) or unrelated donor (n=75). The conditioning regimen for s-SCT consisted of fludarabine (180 mg/m2) + cyclophosphamide (CY, 100 mg/kg) + ATG (10 mg/kg), and the conditioning regimen for u-SCT consisted of TBI (fractionated, 800 cGy) + CY (100–120 mg/kg) ± ATG (2.5 mg/kg) (Lee JW, et al, Biol BMT 2011, 17:101). GVHD prophylaxis consisted of CsA + MTX in s-SCT and FK506 + mini-MTX in u-SCT, respectively. After a median follow-up of 45 and 50 months for s-SCT and u-SCT, respectively, the 3-year estimated OS rates were 92.7 and 89 % for s-SCT and u-SCT (P=0.650), respectively. 15 patients (7 in s-SCT, 8 in u-SCT) died of transplant toxicities, including in s-SCT, acute GVHD (n=1), infections (n=4), and occurrence of MDS or AML (n=2) and in u-SCT, acute GVHD (n=4), chronic GVHD (n=1), infection (n=1), thrombotic microangiopathy (n=1). Nine patients (8 in s-SCT, 1 in u-SCT) developed secondary engraftment failure. The cumulative incidence of acute GVHD (≥grade II) was 4.9% in s-SCT and 44.0% in u-SCT (P<0.001). The cumulative incidence of chronic GVHD also showed higher in u-SCT than s-SCT (4.2% vs 44.4%, P<0.001).

This study showed that survival of u-SCT is comparable to that of s-SCT. Therefore, early application of u-SCT should be considered in patients with SAA/VSAA in case of availability of well matched donor. Because the incidence of GVHD is significantly higher in u-SCT than s-SCT, further study is mandatory to reduce the incidence of GVHD in u-SCT setting.

Disclosures:

No relevant conflicts of interest to declare.
The Impact of ATG/Alg in Preconditioning On the Allogeneic Stem Cell Transplantation for Patients with Acute Leukemia
Authors: Kato Koji , Atsuta Yoshiko , Ohashi Kazuteru , Fukuda Takahiro , Taniguchi Shuichi , Kanamori Heiwa , Sakamaki Hisashi , Yabe Hiromasa , Murata Makoto
Published: October 2019

Abstract 4185

Background:

Since the clinical implication of anti-lymphocyte globulin (ATG/ALG) in allogeneic stem cell transplantation (allo-SCT) is not fully understood, we tried to identify the clinical impact of ATG/ALG in patients with acute leukemia who received allo-SCT in Japan.

Patients and Methods:

We analyzed patients with ALL (n=5494) and AML (n=8115) who received first allogeneic SCT from 1983 to 2009 with (n=356) or without (n=13253) ATG/ALG. Their stem cell sources were bone marrow (BM, n=9056), peripheral blood (PB, n=1918), and cord blood (CB, n=2575) and they were transplanted at 1st complete remission (CR1, n=5681), 2nd CR (CR2, n=2495), and advanced stages (>CR3, n=5033).

Results:

Five year overall survival (5y OS) of all patients with or without ATG/ALG was 33.6% vs 44.5%, respectively (P<0.001) and multivariate analysis showed that ATG/ALG significantly reduced acute GVHD (P<0.001, HR=1.980) as well as chronic GVHD (P<0.001, HR=1.894). According to stem cell sources, 5y OS with or without ATG/ALG was 35.8% vs 47.5% (P<0.001) in BM, 34.7% vs 37.6% (P=0.067) in PB and 18.3% vs 39.9% (P<0.001) in CB. By multivariate analysis, ATG/ALG significantly reduced A-GVHD (P=0.005, HR=1.565) but decreased OS (P=0.004, HR=0.729) in BM, it reduced A-GVHD (P<0.001, HR=2.376) and C-GVHD (P<0.001, HR=2.691) but lowered engraftment (P=0.046, HR=0.810) in PB, and it increased TRM (P=0.004, HR=0.437) with decreased OS (P=0.011, HR=0.576) in CB. In Haplo transplantation (SCT from 2 or 3 antigens of HLA mismatched family donor, n=337), multivariate analysis showed that ATG/ALG did not affect the relapse, TRM and OS but, it significantly lowered engraftment (P=0.002, HR=0.602), and reduced A-GVHD (P<0.001, HR=2.622) as well as C-GVHD (P<0.001, HR=3.834). In contrast to these results, ATG/ALG did not affect the relapse rate irrespective of stem cell source or diagnosis.

Conclusion:

In allogeneic stem cell transplantation for patients with ALL and AML, ATG/ALG contribute in reducing acute and chronic GVHD without affecting relapse rates but it was a risk factor of OS for patients who received BM or CB.

Disclosures:

No relevant conflicts of interest to declare.
A Phase II Study Using Post-Transplant Cyclophosphamide (PTC) As Graft Versus Host Disease (GVHD) Prophylaxis in Patients Undergoing HLA Matched Sibling Donor Stem Cell Transplant (SCT) for Severe Aplastic Anemia (SAA)
Authors: George Biju , Mathews Vikram , Lakshmi Kavitha M , Ahmed Rayaz , Abraham Aby , Srivastava Alok
Published: October 2019

Abstract 4199

Between September 2010 and June 2012, 15 patients with SAA underwent HLA identical sibling donor SCT using post transplant cyclophosphamide for GVHD prophylaxis. The conditioning regimen consisted of Inj Fludarabine 30 mg/m2/day from day -7 to -2 and Inj Cyclophosphamide 50 mg/kg IV on days -3 and -2. Total Body irradiation (TBI) 200 cGy as single fraction was added on day -1 from December 2011 because of concern regarding graft failure. GVHD prophylaxis consisted of Inj Cyclophosphamide administered at 50 mg/kg/day IV on day +3 and +4 post SCT. G-CSF mobilized peripheral blood stem cells (PBSC) was the graft source.

There were 10 males and 5 females with a median age of 25.9 years (range: 8 – 42). The median time from diagnosis to SCT was 7.5 months (range: 2 – 36). All had 6/6 HLA matched sibling donors except 1 who had a 9/10 matched family donor. The median PBSC cell dose infused was 5.4 × 108 MNC/Kg (range: 2.4 – 8.5) and 9.58 × 106CD34/Kg (range: 5.4 – 17.2). Thirteen patients engrafted (86.6%) with a median time to ANC >0.5 × 109/L of 15.4 days (range: 15–17) and Platelet count >20 × 109 of 16.6 days (range: 12–32). Grade II –IV acute GVHD occurred in 3 patients (23%) at 42, 49 and 68 days post SCT. GVHD was grade II in 2 patients and grade IV in 1 patient. Two responded to a combination of cyclosporine and prednisolone while one patient with grade IV GVHD expired with refractory GVHD at median time of 64 days post SCT. Of the 11 evaluable patients, 4 (36.3%) developed chronic GVHD which was limited in all. Two patients who developed de novo chronic GVHD were managed with prednisolone alone. Overall 7 patients (46.6%) have not required any immunosuppression after SCT while 3 have required immunosuppressive therapy for 114, 127 and 225 days respectively At a median follow up of 11 months (range: 1 – 22), 11 (73.3%) are alive and well including 7 patients who did not require any immunosuppressive therapy following SCT.

In conclusion, the use of post transplant cyclophosphamide as GVHD prophylaxis following sibling donor transplant for SAA is associated with low rates of GVHD. What makes it more attractive is the fact that 46% did not require any immunosuppression post SCT. Larger studies are required to understand the utility of this prophylaxis in sibling donor transplants for aplastic anemia.

This trial is registered in the Clinical Trials Registry India - CTRI/2010/091/001480.

Disclosures:

No relevant conflicts of interest to declare.
Cost-Effectiveness of Rituximab As Maintenance Treatment for Relapsed Follicular Lymphoma: Results of a Population Based Study
Authors: Blommestein Hedwig M , Issa Djamila E , Pompen Marjolein , Révil Cédric , Hoogendoorn Mels , Joosten Peter , Zweegman Sonja , Huijgens Peter C. , Uyl-de Groot Carin A.
Published: October 2019

Abstract 4277

OBJECTIVES:

Effectiveness of rituximab maintenance treatment among patients with relapsed follicular lymphoma (FL) has been established in a randomised setting (EORTC20981 trial). Although the golden standard, results might not be generalisable to unselected real-world patient populations. Outcomes research was conducted to calculate real-world cost-effectiveness of second line rituximab maintenance compared to observation in FL patients in the Netherlands.

METHODS:

Two Dutch population-based registries, PHAROS and HemoBase respectively, collected information on patient characteristics, treatment, and resource utilisation on patients diagnosed with FL in the past 20 years. Patients responding to second line chemotherapy were included in the observation or maintenance group. A Markov model was applied to calculate real-world cost-effectiveness.

RESULTS:

Although 735 FL patients entered the registries, only 57 and 49 patients were eligible and included in the observation and maintenance group, respectively. Median age was 61 years and similar in both groups. Differences between the groups were found for second line treatment with rituximab (77% and 92% in the observation and maintenance group p<0.05) and years since diagnosis (p<0.01). Besides, the proportion of people with a partial response was higher in the observation group (60%) compared to the maintenance group (33%). The maintenance group showed higher 3-year overall survival (75% versus 63%) and longer time till next treatment (p<0.01). Compared to the trial, our real-world population was older and fewer patients were diagnosed with stage IV FL. Real-world prescription of rituximab was comparable to the trial although cycles were prescribed more frequent. Daily practice data combined with trial efficacy data resulted in cost-effectiveness ratios between € 3,614 and € 5,246 per life year gained and €3,555 and € 5,156 per quality-adjusted life year.

CONCLUSIONS:

Real-world FL patients were not identical to trial patients emphasising the importance of studying real-world data. Nevertheless, these data also suggest that rituximab is an effective treatment in daily life. However, analysing non-randomised groups is challenging. Careful interpretation is required since observed dissimilarities between the groups suggested the representation of different types of patients. Nevertheless, real-world cost-effectiveness for second line rituximab maintenance was favourable compared to other haematological treatments.

Disclosures:

Pompen: Roche Netherlands: Employment. Révil:Roche Netherlands: Employment.
Expression and Effect of CTCF in Pediatric Acute Lymphoblastic Leukemia
Authors: Zhu Lin , Zhang Han , Liu Xiao , Du Chaohao , Zhu Shanshan , Zhang Wei , Zhao Xiaoxi , Li Zhigang , Bao Shilai , Zheng Huyong
Published: October 2019

Abstract 4298

Acute lymphoblastic leukemia (ALL) is the most frequent-occurring malignant neoplasm in children, but the pathogenesis of the disease remains unclear. In a microarray assay using samples from 100 Chinese children with ALL, CTCF was found to be up-regulated. DNA-binding nuclear protein CTCF (encoded by CTCF gene) is a highly conserved zinc finger protein involved in multiple cellular processes including transcriptional activation/repression, insulation, imprinting and × chromosome inactivation. It has been shown to be associated with cell apoptosis and differentiation in tumors; however, the biological function of CTCF in pediatric ALL is presently unknown.

To investigate the expression features of CTCF in pediatric ALL cells, matched newly diagnosis (ND), complete remission (CR) and relapse (RE) bone marrow samples from 24 patients were collected. Ten ND-CR paired samples (n=20) were selected to detect the mRNA levels of CTCF by Q-PCR. Besides, the protein levels of CTCF at different stages of disease progression were measured by western blot in all patients (20 ND-CR paired samples, n=40; 4 ND-CR-RE matched samples, n=12). To further explore the role of CTCF in the pathogenesis of leukemia, the potential effect of CTCF on the cell apoptosis in lymphoblastic cells was investigated by flow cytometry.

We identified significant up-regulation of CTCF in the ND samples. Importantly, the expression of CTCF returned to normal level after CR, but rebounded in the RE samples. Knock-down of CTCF resulted in nearly 3–fold and 15–fold increases in early and late apoptosis of leukemic cells respectively, which indicated that CTCF is an anti-apoptotic factor and plays an anti-apoptotic role in lymphoblastic cells.

Our results indicate that CTCF may represent a promising indicator of disease progression as well as reflecting the ongoing therapeutic effects of treatment. Furthermore, CTCF serves as an anti-apoptotic factor and potentially contributes to leukemogenesis in pediatric ALL patients.

Disclosures:

Zhang: Beijing Health System High-level Technical Personel Plan: Research Funding. Zheng:Beijing Health System High-level Technical Personel Plan: Research Funding.
Association of Polymorphisms of Cytosine Arabinoside- Metabolizing Enzyme Gene with Therapy Efficacy for Acute Myeloid Leukemia
Authors: Xu Peipei , Chen Baoan , Liu Ran , Feng Jifeng , Cheng Lu , Xia Guohua , Li Yufeng , Qian Jun , Ding Jiahua , Zhu Han , Lu Zuhong
Published: October 2019

Abstract 4328

Background

The cytosine arabinoside (Ara-C)-based chemotherapy is the major remedial measure for acute myeloid leukemia (AML). Deoxycytidine kinase (DCK) and cytidine deaminase (CDA) are the key enzymes in the metabolism of Ara-C. Many single nucleotide polymorphisms (SNPs) and haplotypes of DCK and CDA, which contribute to susceptibility to Ara-C, have been identified in Africans and Europeans. However, there has been no report about the relation among three SNPs in DCK (rs115543896, rs72552079, and rs111454937) and two SNPs in CDA (rs2072671 and rs60369023), and their clinical response to Ara-C for a Chinese population. In this study, we aimed to investigate whether these five SNPs are associated with the therapeutic outcomes of Ara-C-based chemotherapy regimens in patients with AML.

Methods

A total of 151 patients with AML in a Chinese population were enrolled in our study. SNPs genotyping were performed using the MassARRAY system (Sequenom) by means of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) method.

Results

The results illustrated that DCKrs111454937 AA genotype was more frequent in patients with higher platelet count, and A allele frequency was significantly higher in the group £40 years, lower white blood count (WBC) patients group and the group with platelet counts >60′109/L. Meanwhile, both DCKrs72552079 TC (OR=1.225, 95% CI=1.225–9.851, P=0.0192) and CDArs60369023 GA (OR=9.851, 95% CI=1.31–77.93, P=0.0263) significantly improved Ara-C-based chemotherapy response. While DCKrs11554389 AA (OR=0.147, 95% CI=0.027–0.801, P=0.0267) was associated with the decrease of Ara-C-based chemotherapy response.

Conclusion

It is evident that the DCK and CDA polymorphisms might be the important markers for the AML patients' therapy outcomes in a Chinese population.

Disclosures:

No relevant conflicts of interest to declare.
The Results of Chemotherapy for the Elderly Acute Myelogenous Leukemia Patients
Authors: Kim Daesik , Park Yong , Lee Suk-young , Lee Se Ryeon , Sung Hwa Jung , Kim Seok Jin , Kim Byung Soo , Choi Chulwon
Published: October 2019

Abstract 4346

Background

Despite of advances in the treatment for acute myelogenous leukemia (AML), the response of chemotherapy for the elderly is still poor and there is no definite guideline for the elderly AML patients.

Methods

The retrospective analysis with medical chart review was taken to the 82 patients over 65 years old and treated with AML from January 2003 to April 2012 at the Korea University Medical Center. The efficacy of chemotherapy for the elderly patients was evaluated and subgroup analysis was taken to determine which conditions are more effective to the chemotherapy.

Results

Median overall survival period of 82 patients were 3.9 months. 52 patients were treated with chemotherapy (33 patients were standard dose idarubicin plus cytarabine, 19 patients were low dose cytarabine) and 30 patients received best supportive care only. Among the standard chemotherapy group, there were 16 cases of remission (48.5%) after induction chemotherapy. The treatment related mortality was 24.2% and the most common cause was pneumonia sepsis. Median overall survival period of standard chemotherapy group was 7.9 months. In a multivariate analysis, significant factors for longer overall survival were performance status, no underlying heart disease, no fever at diagnosis, high platelet count, low blast count and standard induction chemotherapy. In the subgroup analysis, the efficacy of chemotherapy was observed in the relatively younger patients group (HR 0.437, P =.022), De novo AML group (HR 0.421, P =.025), no underlying heart disease group (HR 0.421, P =.031), high WBC count group (HR 0.306, P =.026), Low platelet count group (HR 0.12, P <.001), high blast counts group (HR 0.233, P =.005), high LDH group (HR 0.21, P=.001).

Conclusion

The result of chemotherapy in the elderly AML patients is poor. However the results of the chemotherapy will be better if the patients are selected appropriately through subgroup analysis.

Disclosures:

Choi: the korean society of hematology: Membership on an entity's Board of Directors or advisory committees.
Practical Experience of Thromboprophylaxis After Lower Limb Replacement – Rivaroxaban Versus Enoxaparin
Authors: Kim Kyoung Ha , Ham Nam Seok , Kim Yang Ki , Choi Hyung Suk , Suh You Sung , Jeon Young Woo , Kim Han Jo , Kim Se Hyung , Bae Sang Byung , Park Sung Kyu , Won Jong-Ho , Hong Dae Sik , Park Hee Sook
Published: October 2019

Abstract 4369

BACKGROUND

Since October 2010, rivaroxaban has been approved by Korean government to be covered by national health insurance reimbursement system as thromboprophylaxis after total hip arthroplasty and total knee arthroplasty. However, there is no available data on outcomes of rivaroxaban as thromboprophylaxis in Korea. We performed a retrospective study to compare the efficacy and safety of venous thromboembolism prophylaxis with enoxaparin or rivaroxaban in 195 consecutive patients undergoing major orthopaedic surgery at our center.

METHODS

This study retrospectively reviewed the medical records of the 195 patients who underwent a total hip replacement arthroplasty or total knee replacement arthroplasty and received thromboprophoylaxis with enoxaparin or rivaroxaban at Soonchunhyang University Hospital between March 2009 and May 2012.

Each patient's medical records included information on age, sex, comorbidities (active malignant disease, renal insufficiency), treatment details (type of surgery, type of anesthesia, duration of surgery,), duration of prophylaxis, efficacy (death, pulmonary embolism, deep vein thrombosis), safety (major bleeding, cerebrovascular accident), cause of drug interruption.

RESULTS

Of 195 patients, 129 patients received thromboprophylaxis with enoxaparin (group 1; our hospital standard since March 2009), 66 received rivaroxaban (group 2; our hospital standard since February 2011). Symptomatic venous thromboembolism was found in 0.7 % of patients in the group 1 (1/129 patients) compared to 1.5 % of group 2 (1/66 patients; p=0.627). No significant differences in the rates of symptomatic VTE were found. However, patients with received rivaroxaban had significantly more rates of major bleeding (0 in group 1 vs 3% (2/66 patients) in group 2; p=0.047). Although group 1 patients were planed receiving thromboprophylaxis with rivaroxaban from day one post operatively, mean time from the end of surgery to first rivaroxaban intatake was 4.2 days.

CONCLUSIONS

Despite lower compliance in rivaroxaban group, venous thromboembolism prophylaxis with rivaroxaban is not inferior to prophylaxis with enoxaparin with regard to the prevention of symptomatic venous thromboembolisms. But, more bleeding complications and wound problems revealed in rivaroxaban group. Further studies and experiences are needed to assess the efficacy and safety of rivaroxaban in clinical practice.

Disclosures:

No relevant conflicts of interest to declare.
The Expressions of CD114, CD117 and STAT5 in CD34+CD59− and CD34+CD59+ Bone Marrow Cells of the Patients with Paroxysmal Nocturnal Hemoglobinuria
Authors: Fu Rong , Ding Shaoxue , Shao Zonghong , Li Lijuan , Liu Hui , Wang Honglei , Zhang Tian
Published: October 2019

Abstract 4404

Objective:

To measure the expressions of granulocyte colony-stimulating factor receptor (G-CSFR, CD114) and stem cell factor receptor (C-KIT, CD117) on the membrane of CD34+CD59− and CD34+CD59+ bone marrow cells of the patients with paroxysmal nocturnal hemoglobinuria(PNH), and the signaling pathway protein STAT5 within the cytoplasm of those cells.

Methods:

The expressions of CD114 and CD117 on the cell membrane and STAT5 protein within the cytoplasm of bone marrow CD34+CD59+ and CD34+CD59− cells from 26 PNH patients and 14 normal controls were examined by flow cytometry (FCM).

Results:

The percentage of CD114 positive cells in CD34+CD59− cells of PNH patients was (43.23±19.77)%,which was significantly lower than that in CD34+CD59+ cells of PNH patients (73.72±17.42) (P<0.01) or normal controls (65.91±13.70)% (P<0.01). There was no statistic difference between the two latter (P>0.05). The percentage of CD117 positive cells in CD34+CD59− cells of PNH patients was (49.20±26.80)%,which was significantly lower than that in CD34+CD59+ cells of PNH patients (67.62±17.41) (P<0.01) or normal controls (70.21±12.68)% (P<0.01). There was no statistic difference between the two latter (P>0.05). The STAT5 MFI in CD34+CD59− and CD34+CD59+ cells of PNH patients and CD34+CD59+ cells of normal controls was (270.01±181.26), (205.05±146.16), (227.39±156.65) respectively. There was no statistic difference among the three groups (P>0.05).

Conclusions:

In PNH, CD114 and CD117 expressed lower on bone marrow PNH clone cells than normal clone cells, but the expressions of signaling pathway protein STAT5 within the cytoplasm was normal.

Disclosures:

No relevant conflicts of interest to declare.
Homoharringtonine Contributes to Imatinib Sensitivity by Blocking EphB4/RhoA Pathway in Ph+ Myeloid Leukemia
Authors: Xiaoli Liu , Huang Bintao , Du Qingfeng , Zhang Jinfang , Xu Na , Xu Lulu , Xiao Xiaozhen , Zhou Xuan
Published: October 2019

Abstract 4420

Objective:

The purpose was to investigate the role of the EphB4 in imatinib (IM) resistance and the mechanism why the homoharringtonine (HHT)+IM regimen gained more treatment profits than simple HHT or IM treating myeloid leukemia.

Method:

The stable under-expressing EphB4 cells (K562-R-EphB4-sh) were obtained. The cell viability and IC50 under the incubation of IM or HHT+IM was tested by MTT. PE Annexin V apoptosis detected the apoptosis rate of K562-R cells. Subcutaneous K562 xenograft models were established. The activated signal proteins in cells and tissues such as RhoA, MEK and ERK were tested by Western blot.

Result:

K562-R-EphB4-sh cell and xenograft were sensitivity to IM. Activated RhoA was not involved in K562-R-EphB4-sh cell and xenograft tissue. But phosphorylation of MEK/ERK was overexpression in K562-R-EphB4-sh cell and tissue. The apoptosis rate reached 58.71 ± 2.39% with K562-R cell incubated with HHT+IM, which was higher to K562-R cell incubated with IM (P=0.002). IC50 of K562-R cell incubated by IM was 5.45 mg/L. But under the stimulation of HHT+IM, IC50 of K562-R decreased from 5.45 to 1.17 mg/L (P<0.001). K562-R xenograft volumes significantly decreased with IM+HHT treatment comparing with before treatment (1692.82 ± 317.14 mm3 versus 975.56 ± 132.42 mm3, P<0.001). HHT blocked the expressions of EphB4/RhoA in K562-R cell and xenograft, but HHT cannot down-regulate the expression of P- MEK/ERK.

Conclusions:

A new marker of IM resistance mediated by the activation of EphB4/RhoA pathway. HHT+IM regimen gained more treatment profits than simple HHT or IM treating myeloid leukemia by blocking EphB4/RhoA pathway in Ph+ myeloid leukemia.

Disclosures:

No relevant conflicts of interest to declare.
Chronic Myelogenous Leukemia in the Era of Tyrosine Kinase Inhibitors: Is Sokal Score Still a Valid Predictor of Prognosis?
Authors: Jain Shivi , Agrawal Kireet , Singh Abhijai , Pattali Shinoj , Haidau Augustin , Kovarik Paula , Catchatourian Rose
Published: October 2019

Abstract 4422

Background:

In the era when the Sokal score was developed (1984), Tyrosine kinase inhibitors (TKI's) were not available for treatment of Chronic Myelogenous Leukemia (CML). With the treatments available then, the 2-year survival in the low risk group was 90% and in the intermediate and high-risk groups was 65%. Since TKI's were approved for treatment of CML in 2001, overall estimated survival at 5 years has improved to 89%.

Aim:

To evaluate risk stratification by Sokal score as an indicator of prognosis in patients with CML in the present era of tyrosine kinase inhibitors.

Methods:

Sokal Score is a prognostic score used to risk stratify patients as low-risk, intermediate-risk and high-risk based on diagnosis based on the spleen size, platelet count, age and blast count. Seventy-eight (78) subjects diagnosed with CML and treated at John H. Stroger Hospital of Cook County between 2000 and 2011 were retrospectively analyzed after institutional review board approval. Ten (10) subjects with blast crisis at diagnosis were excluded from this study. Effect of race, sex, age, white cell count, amount of reticulin fibrosis in bone marrow biopsy, total peripheral blood eosinophil and basophil counts, Lactate Dehydrogenase level, spleen and liver size at diagnosis and, risk stratification by Sokal score on overall survival was evaluated using standard statistical analysis.

Results:

In our population, 27/68 (39.7%) were more than 45 years old, 30/68 (44.11%) were African American, 20/68 (29.4%) were Hispanic, male to female ratio was 2.4:1. WBC>100,000 was observed in 25/68 (51.4%), 57/68 (83.8%) had LDH>200IU/L, 50/68 (73.5%) had palpable splenomegaly >5cm at the time of diagnosis and 67/68 (99%) of subjects had reticulin fibrosis in bone marrow. Of these, 35/67 (52.2%) had mild, 12/67 (17.9%) had moderate and 20/67 (29.8%) had severe fibrosis. According to Sokal score risk stratification, 22/68 (32.3%) were low risk, 40/68 (58.8%) were intermediate risk and 6/68 (8.8%) were high risk at diagnosis. Five year overall survival (OS) in our population was 90%. On univariate analysis, risk stratification by Sokal score at diagnosis was statistically significant for Overall Survival. Subjects with low risk score had better OS as compared to intermediate and high-risk subjects (P=0.007, HR 11.596, 95%CI 1.946–69.103). Similarly, subjects with intermediate score had better OS compared to high-risk group (P=0.007, HR 0.140, 95%CI 0.020–0.539).

Conclusion:

Sokal Score is still a valid predictor of prognosis in this new age of tyrosine kinase inhibitors and can still be used for risk stratification at diagnosis for chronic phase CML patients.

Disclosures:

No relevant conflicts of interest to declare.