bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Coagulation Mechanism for the Mild Bleeding Tendency in a Patient with Severe Hemophilia A Possessing an Arg1781His Mutation.
Authors: Yada Koji , Nogami Keiji , Ogiwara Kenichi , Wakabayashi Hironao , Fay Philip J. , Shima Midori 
Published: October 2019

Abstract
Abstract 2213
The severity and frequency of bleeding appears to be different in hemophilia A (HA) with similar factor (F)VIII activity, as a mild bleeding phenotype has been reported in 10–15% of individuals with severe HA. This heterogeneity in the clinical expression is presently not fully resolved, however. Severe HA patients with the point mutation Arg1781 to His (R1781H) in FVIII also represent a severe to mild/moderate clinical phenotype. We had a patient with mild phenotype (FVIII:C 0.9 IU/dl), presenting with this mutation. In this study, we investigated this mechanism using several global coagulation assays and purified assays with a recombinant FVIII mutant. The levels of all plasma coagulation, anti-coagulation, and fibrinolysis factors were within normal range, except for FVIII. Rotational thromboelastometry using patient whole blood revealed that the clot time and clot firmness time were significantly shortened compared to the control with similar level of FVIII:C, and were comparable to those observed at FVIII:C 5∼10 IU/dl. Thrombin and FXa generation tests using plasmas also demonstrated that the levels of peak thrombin in the former and the initial rate in the latter were comparable to those observed at FVIII:C 5∼10 IU/dl, respectively, supportive of significantly greater hemostatic potential, and potential effects upon formation of the tenase complex consisting of FVIIIa, FIXa, and FX on the phospholipid surface. The addition of excess amounts of FX to control plasma (FVIII:C 0.9 IU/dl) showed a similar waveform pattern in the R1781H patient sample, whilst the addition of FIXa did not show, might suggesting a significant alteration in the interaction of the R1781H patient FVIII(a) and FX. To clarify this mechanism, we prepared and stably expressed a recombinant, B-domainless FVIII mutant, R1781H. Thrombin generation tests using the control plasma with FVIII wild type revealed that the hemostatic function observed with R1781H FVIII (∼0.9 IU/dl) was comparable to that observed at FVIII:C ∼5 IU/dl, indicating the contribution of R1781H on the greater hemostatic potential of patients' plasma. Furthermore, a purified FXa generation assays showed that R1781H possessed an ∼1.9-fold decrease in Km for FX compared to wild type (32.5±3.8 and 58.5±6.1 nM, respectively). This mutant did not affect the FVIIIa binding to either FIXa or phospholipid, however. These results demonstrated that the enhancement of binding affinity of FVIII R1781H for FX appeared to reflect the severity of the HA phenotype. This finding of the higher coagulant potential of the R1781H mutation may suggest utility as a new replacement therapy for HA patients. The addition of this mutant could yield a sufficient hemostatic effect at lower dose, and thus require less protein than a similar dose of native FVIII, as a ‘super-FVIII product’.

Disclosures:
No relevant conflicts of interest to declare.
Hepatitis B Virus Reactivation in Chronic Myeloid Leukemia Treated with Various Tyrosine Kinase Inhibitors: Multicenter, Retrospective Study
Authors: Kim Sung-Hyun , Kim Hyeoung Joon , Kwak Jae-Yong , Kim Jin Seok , Mun Yeung-Chul , Park Joon Seong , Sohn Sang Kyun , Kim Dong-Wook 
Published: October 2019

Abstract
Abstract 3738

Background
BCR/ABL tyrosine kinase inhibitors (TKI) is now a standard initial treatment for chronic myeloid leukemia (CML). Several cases reported that hepatitis B virus (HBV) reactivation were related to imatinib therapy. However, it is still unclear whether imatinib or other TKIs induce HBV reactivation in hepatitis B surface antigen (HBsAg)-positive patients. The aim of this study is to investigate the incidence of HBV reactivation and analyze risk factors associated with HBV reactivation in CML patients who are treated with various TKIs.

Methods
We retrospectively reviewed the medical records from 8 centers in South Korea. HBsAg-positive CML patients under imatinib or other TKIs treatment were analyzed.

Results
702 patients were diagnosed CML from participating centers. HBsAg-positive rate was 6.1% (43/702) at diagnosis. In the 43 HBsAg-positive patients, nine patients received prophylactic therapy and HBV reactivation rate was 34.9% (15/43) (95% CI: 21.0–50.9%). Patients who received prophylaxis did not develop HBV reactivation. The median age and the male to female ratio of the HBV reactivated patients were 47.0 years (range; 22–63) and 4:1, respectively. HBV reactivation according to each TKI treatments were: 12 cases under imatinib, 2 cases under dasatinib, and 1 case under nilotinib. Median time to HBV reactivation was 9.3 months (range; 2.3–68.8 months) (95% CI: 5.9 – 28.5 months). None of the patients died due to HBV reactivation, but one patient received liver transplantation due to hepatic failure. Prophylactic therapy and HBV DNA level at diagnosis were the factors associated with HBV reactivation (P=0.011 and P=0.036, respectively).

Conclusion
This is first report that has analyzed HBV reactivation in HBsAg-positive CML patients during TKIs treatment. Prophylaxis should be considered to prevent HBV reactivation during TKI treatment. Also, we recommend that HBsAg-positive patients with CML receiving TKI treatment be closely monitored.

Disclosures:
No relevant conflicts of interest to declare.
Comparison of IPSS and IPSS-R Scoring in a Population Based Myelodysplastic Syndromes (MDS) Study
Authors: Warlick Erica D. , Hirsch Betsy A. , Nguyen Phuong L. , Cioc Adina , Roesler Michelle A. , Fonstad Rachel , Miller Jeffrey S. , Weisdorf Daniel J. , Ross Julie A. 
Published: October 2019

Abstract
Abstract 3841

Introduction:
The International Prognostic Scoring System (IPSS) has recently been revised (IPSS-R) to capture more inclusive cytogenetic characterization, more stringent blast description, and more detailed cytopenia assignments. To validate the IPSS-R in a prospective cohort of patients, we compared IPSS and IPSS-R categorization within a group of newly diagnosed MDS patients in a prospective population-based epidemiologic study in Minnesota.

Methods:
We identified all newly diagnosed MDS cases in Minnesota between the ages of 20 and 85 years from April 1, 2010 to April 2012. Our process includes rapid case identification by the Minnesota Cancer Surveillance System (MCSS), patient contact and enrollment, central medical review including: 1) independent review by two hematopathologists to confirm diagnosis and WHO subclassification; 2) independent cytogeneticist's review for classification as defined by IPSS and IPSS-R; and 3) medical chart review with prospective calculation of IPSS, IPSS-R, and WPSS by a an oncologist.

Results:
Classification of the 128 patients by IPSS versus IPSS-R is shown (Table)
Kendall's Tau = 0.77
In this comparative classification, IPSS-R scoring refined the MDS prognostic risk groups. Low IPSS remained low risk in the IPSS-R spanning the Very Low and Low groups, while all high risk IPSS remained in the Very High risk group in the IPSS-R. However, those in the INT-1 and INT-2 IPSS categories were inconsistently reclassified in the IPSS-R. INT-1 IPSS spanned from Very Low to High and INT-2 IPSS spanned from Intermediate to Very High in the IPSS-R. While reclassification of this prospective cohort resembles results in the IPSS-R reports, ongoing follow-up will be needed to determine if the survival and AML progression measures are reproducible.

Conclusion:
Until molecular data are available to refine future prognostic scoring systems, the IPSS-R enhances our prognostic risk stratification abilities and is applicable to the general MDS population. As treatment decisions are based on this initial prognostic risk assessment, the more diverse differentiation of risk within the IPSS-R will directly refine prognosis and impact decisions on therapy.

Disclosures:
Miller: Celgene: Membership on an entity's Board of Directors or advisory committees; Coronado Bioscience: Membership on an entity's Board of Directors or advisory committees.
Novel Tyrosine Kinase Inhibitors Trigger Drug Sensitivity of Primary CLL Cells by Controlling Glucosylation of Ceramides
Authors: Schwamb Janine , Feldhaus Valeska , Baumann Michael , Patz Michaela , Brodesser Susanne , Brinker Reinhild , Claasen Julia , Pallasch Christian P. , Hallek Michael , Wendtner Clemens-Martin , Frenzel Lukas P. 
Published: October 2019

Abstract
Abstract 3905

Background:
Apoptosis resistance of chronic lymphocytic leukemia (CLL) cells is mediated by several pro-survival stimuli. In particular, engagement of the B-cell receptor (BCR), CD40-CD40 ligand (CD40L) interaction or stimulation by interleukin-(IL)-4 were identified as major factors to regulate chemoresistance. Sphingolipids are known to be involved in several metabolic pathways involved in chemoresitance. Therefore, we focused on ceramide as pro-apoptotic molecule and its counterpart glucosylceramide, which rather contributes to proliferation and survival.

Methods and Results:
Applying liquid chromatography electrospray ionization tandem mass spectrometry, we revealed a significant decrease of pro-apoptotic ceramide in BCR/IL-4/CD40L-stimulated primary CLL cells compared to untreated controls (p=0.0258, p=0.0478, p=0.0114). Anti-apoptotic glucosylceramide levels were significantly increased after BCR cross-linking (p=0.0435) while other stimuli caused no relevant change in glucosylceramide expression. We identified BCR engagement to catalyze the crucial modification of ceramide to glucosylceramide via the enzyme UDP-glucose ceramide glucosyltransferase (UGCG) (p=0.0001). Besides specific UGCG inhibitors, we could show for the first time that IgM-mediated UGCG expression was significantly inhibited by the novel and highly effective PI3Kδ and BTK inhibitors CAL-101 and PCI-32765, which were able to revert IgM-induced apoptosis resistance of CLL cells. Recently published data revealed sphingolipids to be essential for mediation of apoptosis via mitochondria. Therefore, we chose ABT-737 – a well-known and also mitochondria-targeting drug – as candidate partner for PI3Kδ and BTK inhibition. When combining each tyrosine kinase inhibitor with ABT-737, a synergistic apoptotic effect could be documented, even under protection by BCR stimulation.

Conclusion:
In summary, we could demonstrate that sphingolipids are critically involved in CLL pathogenesis. UGCG could be identified as drugable target by the novel kinase inhibitors CAL-101 and PCI-32765 resulting in even synergistic apoptosis following additional application of ABT-737. Sphingolipids seem to offer further targets providing novel treatment options in CLL.
C.M.W. and L.P.F. contributed equally to this work.

Disclosures:
No relevant conflicts of interest to declare.
Gene Expression Profiling (GEP) of Whole Bone Marrow Biopsies (BMB) in Multiple Myeloma (MM) – Relationship to Plasma-Cell (PC)-Based GEP-Defined Risk and Molecular Subgroups
Authors: Johann Donald , Qu Pingping , Sexton Rachael , Hoering Antje , Epstein Joshua , Yaccoby Shmuel , van Rhee Frits , Usmani Saad Z , Crowley John , Barlogie Bart 
Published: October 2019

Abstract
Abstract 3953
PC-GEP provides great insight into MM heterogeneity as defined by 7 distinct molecular subgroups, along with clinical correlates and prognosis, as identified by the GEP-70 model. As is now increasingly appreciated in MM, a close interaction exists between PC and the bone marrow micro-environment (ME), which results not only in MM bone disease but also contributes to MM progression and drug resistance. We postulated that such interaction could be revealed by performing GEP both on PC and the bone marrow biopsy (BMB) proper. In addition to having demonstrated that BMB-GEP can attain a normal (NL)-like status in comparison with NL donors with favorable prognostic implications, we are now reporting on paired comparisons of BMB-GEP and PC-GEP toward elucidating whether different molecular subgroups (MOLS) (namely, CD-1, CD-2, MAF, MAF-B, MS, HY, PR) and GEP-70-defined prognostic risk groups (RISK) engage the ME differentially. Toward this end, a recently defined BMB-GEP model of 65 genes, distinguishing NL, MGUS/AMM, MM and MM-CR, was applied to determine whether linkage existed to MOLS and RISK. Indeed, based on mean-based statistics, BMB-65 scores varied among MOLS and RISK (both p=0.013). A negative correlation (R=-0.204) existed between BMB-65 and PC-70 scores (p=0.0014). Further analysis within MOLS revealed significant negative correlations within MF (R=-0.57, p=0.0087) and MS subtypes (R=-0.33, p=0.037). None of the other MOLS showed any significant correlations. This is the first demonstration in patient MM samples that MOLS may engage the ME differentially. The more pronounced inverse correlations of MF and MS subtypes reveal a counter-relationship between RISK and BMB-65 score. This implies that with greater aggressiveness of PC, the BMB appears less NL-like, and is thus more modified to support the malignant PC processes. More detailed analyses will be presented in the context of other GEP and clinical parameters, specifically concerning the prognostic implications of BMB scores at baseline.

Correlation between GEP70 score and BMBX 65-gene score within each molecular subgroup Molecular Subgroup N Correlation of GEP70 risk and BMBX 65-gene score P value for testing no correlation CD-1 15 −0.39 0.1494 CD-2 39 −0.22 0.1747 HY 71 −0.15 0.1931 LB 33 0.12 0.4927 MF 20 −0.57 0.0087 MS 40 −0.33 0.0368 PR 25 −0.13 0.55 Overall 243 −0.204 0.001373

Disclosures:
No relevant conflicts of interest to declare.
Once Weekly Subcutanous Bortezomib with Cyclophosphamide and Dexamethasone Is Well Tolerated and Effective As Initial Treatment in Symptomatic Multiple Myeloma
Authors: Simpson David , Liang James , Henderson Ross , Hanna Merit , Merriman Eileen 
Published: October 2019

Abstract
Abstract 4049

Background
Bortezomib became funded for frontline therapy of symptomatic multiple myeloma (SMM) in New Zealand on 1 May 2011. From this date all new patients requiring treatment at our institution, both transplant eligible (TE) and ineligible (TIn), were initially treated with CyBorD consisting of weekly Cyclophosphamide 300mg/m2 PO, Bortezomib 1.6mg/m2 SC(2.5mg/ml) and Dexamethasone 40mg PO. One cycle was arbitrarily defined as 28 days, TE patients received 4–6 cycles CyBorD before ABMT (using 200mg/m2 melphalan), then 3 cycles of VTD (Bortezomib 1.6mg/m2 weekly, Thalidomide 100mg daily, Dexamethasone 40mg weekly) as post transplant consolidation. TIn patients received 4 cycles of CyBorD then 4 cycles of VTD. In June 2011 we changed all patients to subcutaneous bortezomib due to ease of administration and reduced toxicity.

Methods
The records of all untreated SMM patients initiating treatment with Bortezomib at our institution from 1 May 2011 were analyzed for response.

Results
We have treated 25 patients with SMM, 14 TE and 11 TIn. The median age was 68 yrs (range 45 to 88 yrs). The treatments were well tolerated. There was one Bortezomib dose reduction due to toxicity (burning feet on VTD). Injection site skin redness was common, but local reactions were not severe, one patient changed to IV Bortezomib because of this. There were no dose delays due to thrombocytopenia, and no patient had a pre-dose thrombocytopenia of <75 × 109/l. So far 6 patients have completed transplant, no patients have failed to proceed to transplant. There have been no deaths. Responses have improved with each cycle of treatment, after the first cycle the overall response (OR) was 54% (≥VGPR 25%), after 5 cycles the OR rate was 92% (≥VGPR 58%). confirmed CR rates are low, in part as patients are awaiting final bone marrow biopsy.

Response after each cycle

Conclusions
Weekly subcutaneous Bortezomib is well tolerated, and has high patient acceptance. Dose limiting neuropathy is rare, and responses are high when used in combination with CyBorD or VTD.

Disclosures:
No relevant conflicts of interest to declare.
CXCR4 Invalidation Limits the MLL-ENL Induced Leucemogenesis in Vivo
Authors: Zhang Yanyan , Abdelouahab Hadjer , Betems Aline , Wittner Monika , Vainchenker William , Louache Fawzia 
Published: October 2019

Abstract
Abstract 4089
The receptor CXCR4 and its ligand SDF-1 play major physiological roles especially on hematopoietic stem cells homing and retention. Many studies have implicated CXCR4 in the invasion by tumor cells of organs that produce SDF-1. In acute myeloid leukemia, the physiological role of CXCR4 is not fully understood. We used retrovirus to express MLL-ENL oncogene in CXCR4+/+ and CXCR4−/− hematopoietic primitive cells (Lin- isolated from fetal liver) and showed that CXCR4 is dispensable for generation of immortalized colonies in vitro. To determine CXCR4 function in vivo, CXCR4+/+ and CXCR4−/− transformed cells were transplanted into lethally irradiated mice. Whatever their phenotype, the recipient developed a myelo-monocytique leukemia characterized by their expression of Gr-1 and Mac-1. As expected, all recipients of MLL-ENL transduced CXCR4+/+ cells were moribund within 35 to 80 days post transplant (median survival time: 50 days). Strikingly, recipients of MLL-ENL transduced CXCR4−/− cells showed significantly increased lifespan, with a median survival time of 90 days. The cellularity of the peripheral blood of recipients of MLL-ENL transduced cells displayed considerable increases over time although this increase was much lower in CXCR4−/− than in CXCR4+/+ chimera. Bone marrow of MLL-ENL transduced CXCR4−/− chimera had moderately decreased numbers of mononuclear cells. There were important numbers of leukemic CD45.2+/Gr1+/Mac1+/c-kit+ cells in spleen from MLL-ENL CXCR4+/+ chimera which suggested that CXCR4 is important for leukemic progenitors cells retention in the bone marrow and especially in the spleen. The homing capacity of transduced CXCR4+/+ cells is comparable to the CXCR4−/− cells. Finally, more DNA damages were found in the BM cells of MLL-ENL CXCR4−/− chimera. All these results were confirmed by treating of MLL-ENL CXCR4+/+ chimera with CXCR4 inhibitor (TN140).
These results demonstrated that in absence of CXCR4, the cells transduced by oncogene MLL-ENL are capable of generating leukemia in the recipients. However, mice transplanted with MLL-ENL transduced CXCR4−/− FL cells developed acute myeloid leukemia with reduced aggressiveness and organ infiltration, which is associated with induced differentiation and DNA instability. These results indicated that the MLL-ENL progenitors are dependent on CXCR4 for their maintenance in the BM and spleen suggesting that CXCR4 inhibitors might have potential therapeutic applications.

Disclosures:
No relevant conflicts of interest to declare.
Low Dose Azacitidine Maintenance Therapy Following Allogeneic Stem Cell Transplantation for MDS/AML Does Not Interact with Tacrolimus Dosing or Serum Levels
Authors: Lee Hans C. , Howell Joshua , Milton Denái , Giralt Sergio A , Chen Julianne J , Rondon Gabriela , Champlin Richard E. , Parmar Simrit , De Lima Marcos 
Published: October 2019

Abstract
Abstract 4209

Background:
Recurrence of disease remains a significant cause of morbidity and mortality in patients who undergo allogeneic SCT for AML and MDS. Low-dose azacitidine is currently under investigation in the post-transplant setting with the goal of prolonging disease-free survival and decreasing relapse rates. It is unclear if there is potential pharmacologic interaction between azacitidine and dose-adjusted tacrolimus used to prevent post-transplant graft-versus-host disease (GVHD), a clinically relevant question since any resultant tacrolimus under- or over-dosing may lead to increased risk of GVHD or drug toxicity, respectively. We hypothesized that azacitidine does not significantly interact with tacrolimus levels and performed a retrospective analysis to test this hypothesis.

Patients and Methods:
We reviewed tacrolimus daily doses and serum drug levels of 62 AML and MDS patients who received azacitidine maintenance therapy (n=30) or no maintenance therapy (n=32) following allogeneic stem cell transplantation at MD Anderson Cancer Center between 2008–2012. Patient characteristics are summarized in the Table. Patients in the maintenance cohort received subcutaneous azacitidine at 32 mg/m2 on days 1–5 repeated every 28 days starting at a median time of post-transplant day +65 (range 43–100). Tacrolimus doses and serum levels were averaged for 28 days for each patient before and after initiation of azacitidine maintenance and at day +66 in the non-maintenance cohort. Differences between the two cohorts in their mean change of tacrolimus doses and serum drug levels were assessed using a Student's t-test.

Results:
Mean (SD) oral tacrolimus doses pre- and post-maintenance therapy were 2.61 (2.13) mg daily and 2.44 (2.15) mg daily in the azacitidine group and 2.54 (1.86) mg and 2.23 (1.39) mg daily in the non-azacitidine cohort. This resulted in a mean change in tacrolimus dosing of -0.17 (1.16) mg daily in the azacitidine patients and -0.31 (1.10) mg daily in the non-maintenance group (p=0.62). Mean (SD) serum tacrolimus levels pre- and post-maintenance therapy were 8.07 (1.16) ng/mL and 7.58 (2.32) ng/mL in the azacitidine group and 8.23 (1.49) ng/mL and 7.10 (1.69) ng/mL in patients on no maintenance therapy. This resulted in a mean change in serum tacrolimus levels of -0.49 (2.75) ng/mL in the azacitidine cohort and -1.13 (2.04) ng/mL in the non-maintenance group (p=0.30).

Conclusion:
Maintenance azacitidine therapy following allo-SCT for AML and MDS does not appear to affect concurrent tacrolimus dosing or serum drug levels.

Disclosures:
Off Label Use: azacitidine: off-label use as maintenance therapy following allogeneic stem cell transplant for MDS/AML. Champlin:Otsuka: Research Funding. De Lima:Celgene: Research Funding.