bluuebunny/crossref_metadata_2025_split huggingface dataset:
G-CSF Priming, Clofarabine and High Dose Cytarabine (GCLAC) for Relapsed or Refractory Acute Myeloid Leukemia (AML).
Authors: Becker Pamela S. , Estey Elihu , Petersdorf Stephen , Storer Barry E , Appelbaum Frederick R 
Published: October 2019

Abstract
Abstract 2068
Poster Board II-45

Background:
Clofarabine is active in both relapsed and newly diagnosed AML. Clofarabine in combination with ara-C at a dose of 1 g/m2 daily for 5 days resulted in 52% complete remission (CR) in newly diagnosed patients age 50 or older. (Faderl et al Blood 108:45, 2006), Addition of low dose cytarabine (ara-C) improved efficacy as compared to clofarabine alone in untreated patients age 60 or older (Faderl et al Blood 112:1638, 2008). As high dose ara-C has considerable efficacy in AML, we combined clofarabine with higher dose ara-C (HiDAc) and granulocyte colony-stimulating factor (G-CSF) priming for patients with relapsed AML or AML that failed to respond to initial therapy. GCLAC is based on the FLAG regimen, substituting clofarabine for fludarabine, given the former's greater anti-AML effect.

Methods:
We initially conducted a phase 1 trial in 19 pts and identified 25 mg/m2 daily days 1-5 as the MTD of clofarabine when combined with ara-C 2 g/m2 daily days 1-5 and G-CSF 5 mcg/kg subcutaneously, beginning 1 day before chemotherapy and continuing daily until neutrophil recovery. A phase 2 expansion was then conducted at the MTD.

Results:
We have treated 38 patients (pts), age range 19-66 years, median 51, 22 at the MTD. Twenty pts received GCLAC as 1st salvage, 15 at the MTD. Seven of the 20 had relapsed after a median 1st CR duration of 6 mos while 13 had not responded to initial 3+7 induction therapy, including 4 who were refractory to > 1 course. The CR rate for all patients or all patients at the MTD was 45% and the CR +CRp rate at the MTD was 64%. These rates are 50% CR (95%CI 27-73%) and 65% CR+CRp among 1st salvage pts (95% CI 41-85%), respectively, and 70% CR + CRp excluding pts who relapsed after allogeneic SCT. Median time to neutrophil recovery (ANC>500) was 21 days (range 13 to 39), and to platelet recovery (platelet count >100,000), 29 days (range 21-42). Four of 22 pts had serious infections and/or asymptomatic grade 3 LFT elevations, a rate not in excess of that seen with other ara-C-containing salvage therapies. Sixty percent of the first salvage patients had poor risk cytogenetics, and 80% of CRs were observed after the first course of therapy. Median overall survival was 7.4 months, and event free survival, 4.3 months. Using a prognostic model that derives expected CR rates with HiDAc or FLAG based on 1st CR duration and number of prior salvage therapies (Blood 1996;88:756), the ratio of observed (with GCLAC) to expected CR was 2.5:1.

Conclusion:
Based on its efficacy, formal comparisons of GCLAC with other salvage regimens are warranted and the combination should also be investigated in untreated pts.

Disclosures:
Becker: Genzyme Oncology: Research Funding. Off Label Use: Clofarabine is approved for relapsed or refractory pediatric ALL .
Robotic High Thoroughput Multiplex PCR Single-Nucleotide Polymorphism Genotyping of Apheresis Platelet Donors.
Authors: Shehata Nadine , Hannach Barbara , Banning Nancy , Freedman John , Denomme Greg 
Published: October 2019

Abstract
Abstract 2106
Poster Board II-83
Background Phenotyping blood donors for human platelet antigens (HPAs) can be limited by the availability of antibodies and methodologies. Robotic high throughput multiplex polymerase chain reaction (PCR) single-nucleotide polymorphism (SNP) technology provides the opportunity to perform mass genotyping for HPAs to screen apheresis donors who are negative for antigens implicated in alloimmune thrombocytopenia. This technology needs to be validated by standard polymerase chain reaction-SSP to establish a repository of platelet donors to allow for timely and adequate platelet support for patients requiring HPA-matched platelets. The objective of this study is to validate the use of high throughput SNP technology. Methods This is a prospective cohort study of 750 regular apheresis donors. Platelet apheresis donors were identified from Canadian Blood Services' Toronto Centre and genotyped for HPA 1-5 and 15 using high throughput SNP (SNPStream®) technology. HPAs were genotyped using both the sense and antisense DNA strands of each polymorphism to ensure maximum specificity. The genotypes identified by SNP were confirmed by standard methods thus all donors found to be negative for antigens implicated in alloimmune thrombocytopenia were retested using manual (sequence specific SSP-PCR at Canadian Blood Services' Platelet Immunology Laboratory and at the Toronto Centre. Results Of the 750 donors that were screened, 130 donors were found to be negative for antigens implicated in alloimmune thrombocytopenia based on SNP technology. The table illustrates genotyping results using SNP technology and SSP-PCR confirmation to date. In some instances, donors were homozygous for two low frequency HPA genotypes: 2 donors were homozygous for both HPA-1b/b and -2b/b, 6 donors for HPA-1b/b and -3b/b, 1 donor for HPA-2b/b and -3b/b, 1 donor for HPA-1b/b and -5b/b, 10 donors for HPA-1b/b and -15b/b, 4 donors for HPA-5b/b and -15b/b and 1 donor for HPA-2b/b and 15-b/b.
HPA System Number of Genotypes Identified by SNP Technology Discrepant results Identified by SSP HPA-1 b/b 15 2 (13%) HPA-2 b/b 8 3 (27%) HPA-3 b/b 25 1 (4%) HPA-5 b/b 1 0 HPA-15 b/b 9 1 (11%)

Conclusions:
Robotic high throughput multiplex PCR SNP is potentially useful for mass genotyping of apheresis platelet donors and can identify both low frequency antigen-negative donors and combinations of these genotypes. This technology needs to be further developed.

Disclosures:
No relevant conflicts of interest to declare.
Tolerance Induced by B-Cell Gene Therapy: Expansion and Increased Activity of Antigen-Specific Tregs.
Authors: Skupsky Jonathan , Su Yan , Scott David W. 
Published: October 2019

Abstract
Abstract 2129
Poster Board II-106
Patients with hemophilia A treated with coagulation co-factor VIII (FVIII) may mount a response against this therapeutic protein, thus forming antibodies that block FVIII function (inhibitors). To treat those currently forming inhibitors (or to prevent inhibitor formation), a B-cell based gene therapy has been used that employs a chimeric antigen-Ig tolerogenic construct comprised of FVIII C2 and A2 domains. We have shown that hemophilic mice receiving B cells transduced with these Ig fusion proteins have diminished Bethesda titers, even after further FVIII treatment. Tolerogenic B-cell therapy requires the presence of CD25+ regulatory T cells (Tregs). We have recently shown that tolerogenic B-cell treatment results in the increase of antigen-specific Treg cells and a selective loss of antigen-specific responder cells. To extend these studies, we have adapted in vitro suppression assays using Tregs isolated from treated and control mice. Using CFSE dilution as a measure of T-cell responsiveness to FVIII, we now show that Tregs from treated mice are more suppressive than those from control treated animals. In order to follow antigen-specific Tregs, we repeated these studies in DO11.10 T-cell receptor transgenic mice that recognize an OVA peptide. Tregs from DO11.10 mice treated with an OVA-Ig construct are also more suppressive than polyclonal Tregs when stimulated with OVA peptide. Although functionally superior, there appear to be no discernible phenotypic differences in these Treg populations. These changes in the lymphocyte population shift the balance away from effector function towards a tolerogenic phenotype and may provide the basis for future therapies in hemophilia A patients with inhibitors. (Supported by NIH RO1 HL061883, NIH T32 HL007698, and AHA Fellowship 0815219E)

Disclosures:
No relevant conflicts of interest to declare.
Treatment with the CXCR4 Antagonist AMD3100 Enhances Antibody Mediated Killing in Disseminated Lymphoma Models.
Authors: Siders William , Hu Yanping , Gale Matthew , Jacques Gary , Fogle Robert , Shields Jacqueline , Garron Carrie , Kaplan Johanne 
Published: October 2019

Abstract
Abstract 2717
Poster Board II-693
Interactions between chemokines and their receptors play an important role in cancer biology and have been shown to influence several processes such as tumor growth and the development of metastatic lesions. Stromal cell derived factor-1 (SDF-1) is a chemokine that binds to the CXCR4 chemokine receptor and stimulates B cell growth. CXCR4 is frequently over-expressed on tumor cells and the SDF-1/CXCR4 axis has been reported to play a role in promoting survival, angiogenesis and metastasis. The role of the stroma, in particular SDF-1/CXCR4 interactions, in providing a “survival niche” for tumor cells is well described for both hematological and solid tumors. We hypothesized that disruption of the protective microenvironment of tumor cells through antagonism of the SDF-1/CXCR4 axis may enhance the sensitivity of the tumor cells to treatment with anti-cancer agents such as monoclonal antibodies. Mozobil (AMD3100) or its structurally related analog, AMD3465, were used in combination with either Campath (anti-CD52) or Rituxan (anti-CD20) in lymphoma xenograft models to determine whether enhanced tumor protection could be observed. Flow cytometry analysis of lymphoma cell lines confirmed the cell surface expression of high levels of CXCR4 as well as the CD20 and CD52 target antigens. Lymphoma cells were seeded by intravenous injection and tumor-bearing mice were treated with multiple injections of the CXCR4 antagonists AMD3465 or AMD3100 alone or in combination with monoclonal antibodies. Treatment with AMD3465 as a single agent was sufficient to increase survival of the animals compared to untreated controls. In addition, the combination of AMD3465 and Campath showed a synergistic effect with a prolongation of survival greater than that obtained with either agent alone (p<0.01). Similarly, combination of AMD3100 and Rituxan also resulted in a significantly prolonged survival compared to either agent alone (p=0.0340). In vivo imaging using a Raji-luciferase cell line also confirmed the impact of treatment on tumor burden. These results suggest that there is a potential role for CXCR4 antagonists in combination with a B-cell targeted therapy in the treatment of B-cell malignancies in the clinic.

Disclosures:
Siders: Genzyme Corporation: Employment. Hu:Genzyme: Employment. Gale:Genzyme: Employment. Jacques:Genzyme: Employment. Fogle:Genzyme: Employment. Shields:Genzyme: Employment. Garron:Genzyme: Employment. Kaplan:Genzyme: Employment.
A Phase II Trial of Rituximab-CHOP Chemotherapy Followed by Yttrium 90 (90Y) Ibritumomab Tiuxetan (90Y-IT) for Previously Untreated Elderly Diffuse Large B-Cell Lymphoma (DLBCL) Patients.
Authors: Zinzani Pier Luigi , Fina Mariapaola , Tani Monica , Stefoni Vittorio , Gandolfi Letizia , Broccoli Alessandro , Pellegrini Cinzia , Derenzini Enrico , Rossi Giuseppe , Angelucci Emanuele , Gaidano Gianluca , Petti Maria Concetta , Martelli Maurizio , Vitolo Umberto , Fanti Stefano , Baccarani Michele 
Published: October 2019

Abstract
Abstract 2720
Poster Board II-696

Introduction:
In 2008 we published a phase II trial abuot the combination of 6 cycles of CHOP plus 90Y-IT for previously untreated elderly patients with DLBCL. The CCR was 95% with OS at 2 years of 95% and PFS at 2 years of 75%. The results of this study support a further evaluation of 90Y-IT in combination of chemotherapy. We conducted a prospective, single-arm, non-randomized, phase II trial with CHOP plus Rituximab followed by 90Y-IT reducing the number of CHOP cycles from 6 to 4 but introducing Rituximab. The rational is to utilize all the therapeutic approaches (chemotherapy, immunotherapy and radioimunotherapy) reducing conventional chemotherapy and probably related toxicity.

Patients and Methods:
Patient elegibility was represented by: patients older than 60 years with biopsy proven, untreated, bidimensionally mesurable stage II, III or IV DLBCL. Expression the CD-20 antigen; WHO performance status of 0 to 2. patients were treated with standard CHOP chemotherapy plus Rituximab every 21 days for 4 cycles. Patients were restaged 4 to 6 weeks after completion of 4 cycles of R-CHOP chemotherapy. Patients achieving CR, PR or SD after chemotherapy were eligible for consolidation with 90Y-IT provided the granulocyte count was greater than 1500/microl, the platelet count exceded 100.000/microl and the bone marrow examination at the completion of chemotherapy demostrated no more than 25% involvement with lymphoma. All patients were to receive a single dose of 90Y-IT 14.8 MBq/kg (0.4 mCi/kg). Fifty-five patients have been enrolled: 26 were male and 29 female; the median age was 70 years (range 60–83); 17 were stage II, 38 were stage III-IV.

Results:
Fifty-one patients had completed the R-CHOP treatment and the overall response rate was 94.1% including 30 (58.8%) of patients in CR and 17 (35.3%) in PR. Treatment was well tolerated; grade 3–4 AEs are comparable with previous experience and the most common grade 3–4 AEs was neutropenia. At this time 47 patients had just received 90Y-IT and 45 are evaluable. In particular, 9/17 (52.9%) patients converted from PR to CR after treatment with 90Y-IT.

Conclusions:
These preliminary data indicate that radioimmunotherapy appears highly effective and feasible as “consolidation” after 4 cycles of immunochemotherapy in elderly DLBCL patients, improving quality of response without any cumulative toxicity.

Disclosures:
Off Label Use: The drug Yttrium 90 (90Y) Ibritumomab Tiuxetan (90Y-IT) (Zevalin) is off-label for Diffuse Large B-Cell Lymphoma (DLBCL).
Combining RAD001 (Everolimus) with Proteasome Inhibitors Bortezomib (Velcade) or MG132 Significantly Enhances Pre-B ALL Cell Death in Vitro.
Authors: Saunders Philip O. , Bradstock Kenneth F , Bendall Linda J. 
Published: October 2019

Abstract
Abstract 2743
Poster Board II-719
Mammalian target of rapamycin (mTOR) inhibitors have shown potential as novel therapeutic agents with efficacy against a wide range of tumors including precursor-B acute lymphoblastic leukemia (pre-B ALL). We have previously reported RAD001 (16μM) induces JNK pathway activation in pre-B ALL cells and that combining RAD001 with DNA damaging agents in vitro significantly enhanced JNK dependent death, via a caspase dependent mechanism. We sought to evaluate agents, which may favor JNK activation and promote JNK dependent cell death in pre-B ALL cells. Bortezomib and MG132 have both been reported to activate the JNK pathway via death receptor activation, with reported efficacy in pre-B ALL. Consistent with the literature we observed enhanced JNK pathway activation in pre-B ALL cells treated with bortezomib. Analysis of annexin V and 7AAD expression by flow cytometry utilizing JNK inhibitor SP600125 (5μM) showed that a significant proportion of pre-B ALL cell death observed with bortezomib was JNK dependent.
Combining RAD001 (4–16μM) with bortezomib in vitro (10–20nM) significantly enhanced cell death in pre-B ALL cell lines and patient cases at 24 hours. This observation was supported by equivalent observations combining MG132 (250–500nM) with RAD001 (8–16μM). The degree of enhanced killing was greater than that achieved combining RAD001 (16μM) with DNA damaging agents. Enhanced killing was also achieved at a significantly lower dose of RAD001 relative to combination therapy with DNA damage. Utilizing JNK inhibitor SP600125 (5μM) we determined that a significant proportion of enhanced killing was JNK dependent.
In conclusion we have identified two novel and clinically available agents which when combined can significantly enhance pre-B ALL cell death. Our observations suggest combining agents which induce JNK activation has the potential to enhance clinical responses in pre-B ALL, particularly for patients with advanced or relapsed disease, for whom treatment with cytotoxic chemotherapy offers little hope of improved survival. In vivo studies will provide further insight into this promising strategy.

Disclosures:
No relevant conflicts of interest to declare.
Impact of Cytogenetic Abnormalities On Outcome Among Patients with Relapsed/Refractory Multiple Myeloma Treated with Bortezomib: Adverse Effect of 1q21 (CKS1B) Amplification.
Authors: Chang Hong , Trieu Young , Qi Connie , Xu Wei , Reece Donna E. 
Published: October 2019

Abstract
Abstract 2826
Poster Board II-802
To investigate whether genetic risk factors affect the outcome of relapsed/refractory myeloma patients undergoing bortezomib therapy, we evaluated the clinical features of 85 patients treated with bortezomib and correlated with the high-risk cytogenetic abnormalities as detected by interphase cytoplasmic fluorescence in situ hybridization (cIg-FISH). Forty (47%) patients had an objective response to bortezomib with median progression free (PFS) and overall survivals (OS) of 9.4 and 12.6 months, respectively. cIg-FISH determination of del(13q), del(17p), del(1p21), t(4;14), and amp. (1q21)(CKS1B) was done on 79, 77, 77, 78, and 80 cases and the frequency of their detection was 38%, 22%, 26%, 18%, and 39%, respectively. There was no statistically significant difference in terms of response or duration of response to bortezomib for patients with or without any of the cytogenetic abnormalities. PFS was also comparable among patients with and without the aforementioned genetic markers. However, patients with 1q21(CKS1B) amplification had significantly shorter OS than those without such abnormality (5.3 vs. 24.6 months, p=0.0005). Multi-variate analysis adjusting for all 5 high-risk genetic factors confirmed that 1q21(CKS1B) amplification is an independent risk factor for OS (p=0.008). Improved therapeutic strategies may be required for this subgroup of patients.

Disclosures:
Reece: Ortho Biotech: Honoraria, Research Funding.
Leukemogenic Transformation by Anterior HOXA-Cluster Genes.
Authors: Buhl Sebastian , Maethner Emanuel , Slany Robert K. 
Published: October 2019

Abstract
Abstract 2962
Poster Board II-938
HOX homeobox genes are important regulators of normal and malignant hematopoiesis and abdominal-type HOXA-cluster genes, in particular HOXA7 to HOXA10, are highly leukemogenic. However, little is known about the transforming abilities of anterior HOXA genes HOXA1 to HOXA6 despite a high prevalence of anterior HOX-expression in acute leukemia. Here we performed a comprehensive assessment of the oncogenic potential of every HOXA gene in primary hematopoietic cells. With exception of HOXA2 and HOXA5 all other HOXA genes caused a block or delay of hematopoietic differentiation in serial replating assays and all HOX genes also cooperated with Meis1. No evidence for the alleged tumor-suppressor function of HOXA5 could be found. Whereas all other active HOXA genes induced the outgrowth of mixed granulocytic/monocytic cells, HOXA13 preferentially specified the development of monocytes/macrophages. Albeit more weakly than HOXA9 also the anterior HOXA genes HOXA1, HOXA4, and HOXA6 transformed cells and generated permanent myelomonocytic cell lines arrested at various stages of differentiation. HOX-RNA profiling revealed that each of these lines also transcribed HOXA9. However, kinetic studies with inducible HOX-derivatives showed that HOXA9 expression was not under control by anterior HOXA proteins. Cellular differentiation was induced immediately after loss of anterior HOX activity and HOXA9 down regulation was a secondary event during maturation. This proves that anterior HOX proteins are able to transform hematopoetic cells through an individual contribution independent of HOXA9. In summary our results explain how HOXA9 can predominate in hematologic malignancies while simultaneously it is not necessarily required for transformation.

Disclosures:
No relevant conflicts of interest to declare.
Racial Differences in Thrombotic Risk Factors Associated with Adverse Pregnancy Outcome Among Women Obtaining Care in US Thrombosis and Hemostasis Centers.
Authors: Philipp Claire S. , Faiz Ambarina , Shrimanker Sheetal , Beckman Michele G , Bockenstedt Paula L. , James Andra H , Manco-Johnson Marilyn J. 
Published: October 2019

Abstract
Abstract 2982
Poster Board II-958
Pregnancy complications such as recurrent miscarriage, intrauterine growth restriction (IUGR), and preeclampsia are common and have been associated with thrombophilia. However racial differences are poorly described for this population. The objective of this study was to determine racial differences in unexplained adverse pregnancy outcome among women obtaining care in the CDC Thrombosis and Hemostasis Centers Research and Prevention Network. Uniform data were prospectively collected from August 2003 to March 2009 in consenting women with a history of adverse pregnancy outcome obtaining care at Network Centers for pre-pregnancy, pregnancy, or postpartum consultation and/or management. Data from 407 women (mean age 38.5 ±12 yrs), including 326 white women (mean age 39.4 ± 12 yrs), and 60 black women (mean age 33.9 ± 11 yrs) were analyzed. Black women had significantly more second trimester pregnancy losses compared to white women (35% vs 22%, p=0.03) but the proportions of 1st trimester losses, 3rd trimester losses, IUGR, prematurity, abruption, and preeclampsia were not significantly different. The risk of thrombophilia differed by race, with Factor V Leiden mutation more common in white women compared to black women (19% vs 3%, p=0.002). Protein S deficiency was more common in black women compared to white women overall (15% vs 5%, p=0.006) and in the subgroup of non-pregnant women (14% vs 5%, p=0.04). There was no significant difference in the proportion of white and black women with antiphospholipid antibodies. Among 285 women evaluated when non-pregnant, body mass index (BMI) ≥ 25 was more frequent in black women (83%) compared to white women (63%) (p=0.04). Overall, black women had a significantly higher proportion with hypertension (27% vs 11%, p=0.002) and sickle cell disease (7% vs 0,%, p< 0.001). There was no significant racial difference in history of pregnancy associated, provoked, or idiopathic venous thromboembolism (VTE). A family history of thrombophilia (6% vs 0%, p=0.05), VTE (22% vs 7%, p=0.005), myocardial infarction (MI) or stroke (12% vs 0%, p=0.0042) was significantly more common in white women compared to black women (overall 32% vs 8%, p<0.0002). This study demonstrates that comorbidities including hypertension, sickle cell disease and BMI≥25 are more prevalent in black women with adverse pregnancy outcomes whereas white women have a higher prevalence of Factor V Leiden mutation, and positive family history of thrombophilia, VTE, MI, and stroke.

Disclosures:
No relevant conflicts of interest to declare.