bluuebunny/crossref_metadata_2025 huggingface dataset:
Fludarabine-Associated Acute Promyelocytic Leukemia
Authors: Hess Clayton B , Ehmann W. Christopher
Published: October 2019

Abstract 4383

Here we describe a case of acute promyelocytic leukemia (APL) (M3 leukemia) which developed in a patient treated with single-agent fludarabine for lymphoplasmacytic lymphoma (Waldenstrom's macroglobulinemia [WM]).

This 69-year-old male was diagnosed with WM in 2003. He received single-agent therapy with 4 cycles of fludarabine, after having an adverse reaction to his first and only dose of rituximab. Therapy was completed in 2007, with the patient in a complete remission. Two years later, he presented with leukocytosis and a consumptive coagulopathy. A bone marrow biopsy showed 90% abnormal promyelocytes with prominent Auer rods. PML/RARA fusion was positive by FISH. PCR was positive for t(15;17) (PML/RAR long (bcr1 and bcr2) and short (bcr3) form translocations. Cytogenetic studies showed abnormal 3q, monosomy 15 and 17, 2 unidentified marker chromosomes and a complex insertional translocation of chromosomes 15 and 17, with a PML/RARA fusion. The patient's APL was treated with ATRA and 7+ 3 chemotherapy because of a rising number of blasts in his peripheral blood. His subsequent clinical course was complicated by refractory atrial fibrillation, renal failure, a catheter-related upper-extremity deep venous thrombosis, and severe deconditioning. The patient died four months later from probable sepsis. A marrow performed two weeks prior to his death showed a complete hematologic remission, and no evidence of either Waldenstrom's or acute promyelocytic leukemia.

There are forty-eight cases published of hematologic malignancies which occurred after single-agent nucleoside-analog treatment: none were APL. Twenty-four of these cases consisted of a lymphoid transformation to a more aggressive histology and twenty-four cases described development of a myeloid leukemia or myelodysplastic syndrome. In these patients, a variety of chromosomal changes were demonstrated with abnormalities of chromosome 7 being the most frequently observed (exclusively in those with myeloid disorders). There were no cases of a t(15;17) reported. We then reviewed all documented cases of therapy-related APL. No cases implicating nucleoside analogs were found. Topoisomerase inhibitors were the most common agents implicated as were radiation, anthracyclines, and alkylating agents.

Because fludarabine was the only chemotherapy agent to which the patient was exposed, and the patient developed APL within the time frame expected for therapy-related leukemogenesis, we conclude that this is the first reported case of fludarabine-associated APL.

Disclosures:

No relevant conflicts of interest to declare.
Comparison of Branded Enoxaparin (Lovenox) and a Biosimilar Version of Enoxaparin (Fibrinox)
Authors: Jeske Walter , McGeehan Elizabeth , Iqbal Omer , Hoppensteadt Debra , Walenga Jeanine M. , Fareed Jawed
Published: October 2019

Abstract 4385

Several biosimilar versions of branded enoxaparin (Lovenox, Sanofi-Aventis, Paris, France) have recently become available throughout the world. These biosimilar enoxaparin preparations are distributed by multiple suppliers in Asia and in North and South America. Enoxaparin represents a complex mixture of oligosaccharides obtained by alkaline depolymerization of porcine mucosal heparin. It is the most widely used low molecular weight heparin which has been validated for clinical use in multiple indications. While the molecular profile and anti-Xa potencies of some of the biosimilar versions of enoxaparin are comparable, product based differences have been reported amongst some of the biosimilar versions of enoxaparin. The purpose of this study was to compare the biochemical and pharmacologic profile of one biosimilar version of enoxaparin, namely Fibrinox (Sandoz SA, Buenos Aires, Argentina) with the branded product Lovenox. The products were compared in equigravimetric amounts, assuming equivalent potency (100 AXa U/mg). Both products exhibited comparable molecular weight profiles in terms of average molecular weight and oligosachharide distribution. Analysis of the antithrombin binding hexasaccharide fractions of Fibrinox and Lovenox indicated the presence of eight distinct hexasaccharides. The relative proportions these hexasaccharides differed between Fibrinox and Lovenox. The anti-Xa and anti-IIa activities were comparable. In the whole blood clot-based assays such as TEG and ACT, both agents produced similar anticoagulant effects. In the plasma based assays such as the APTT, Heptest and thrombin time, both products showed comparable anticoagulant effects in the normal human pooled plasma samples. However, in plasma samples collected from patients with liver disease who were apparently anticoagulant free, the two products showed differences in their anticoagulant effects in the APTT assay (p<0.05). In the TF mediated thrombin generation assay, Fibrinox produced a stronger inhibition of thrombin generation compared to Lovenox (IC50; Fibrinox, 1.6 μ g/ml, Lovenox 2.2 μ g/ml). No differences were observed between the two products in the agonist induced platelet aggregation assays. However in the 14C serotonin release study, Fibrinox produced a stronger HIT serum mediated 14C release (p<0.05). Differences in the fibrinokinetic profile and the inhibition of thrombin activatable fibrinolytic inhibitor activation were observed with these LMWHs. These studies suggest while both the molecular profile and the pharmacopoeial potency of Fibrinox is similar to the branded product, these drugs can be differentiated in some of the other assays and should be evaluated in terms of additional pharmacologic mechanisims to demonstrate bioequivalence.

Disclosures:

No relevant conflicts of interest to declare.
Prevention of Deep Vein Thrombosis In Patients In the United States with Infectious Diseases
Authors: Amin Alpesh N , Lin Jay , Wiederkehr Daniel
Published: October 2019

Abstract 4389

Background:

Hospitalized patients with infectious diseases are at risk of venous thromboembolism (VTE), encompassing both deep-vein thrombosis (DVT) and pulmonary embolism (PE). Our analysis evaluated real-world thromboprophylaxis use and DVT/PE rates in patients with infectious diseases in hospital, and for 30 days post-discharge.

Methods:

Data were extracted from the US Premier Perspective(tm)-i3 Pharma Informatics linked database for patients with infectious disease (International Classification of Diseases Ninth Revision codes for infectious and parasitic diseases, skin infections, chronic infection, and postoperative infection) who had been admitted January 2005–November 2007. Included patients had at least 6 months’ continuous plan enrollment and were aged ≥ 18 years. Patients with a diagnosis of atrial fibrillation were excluded, as were patients with a hospital stay of 0 days or > 30 days.

Results:

Of the 5,488 at-risk patients analyzed, 31% received inpatient pharmacological or mechanical DVT prophylaxis, and 3.2% received outpatient pharmacological DVT prophylaxis. Mean ± standard deviation duration of prophylaxis was 1.1 ± 2.4 days for inpatients and 0.8 ± 4.6 days post-discharge, with a total duration of 1.9 ± 5.4 days. DVT/PE occurred in 3.61% of patients during hospitalization, and 0.98% of patients were rehospitalized or treated in the outpatient setting for DVT/PE.

Conclusions:

Our analysis highlights the considerable rate of DVT/PE and the underuse of DVT prophylaxis in hospitals. Furthermore, DVT/PE risk persisted post-discharge, yet few patients received outpatient prophylaxis. Improved prevention of DVT is required across the continuum of care to reduce preventable mortality and morbidity in patients with infectious diseases.

Acknowledgment:

this study was funded by sanofi-aventis U.S., Inc. The authors received editorial/writing support in the preparation of this abstract provided by Hester van Lier, PhD of Excerpta Medica, funded by sanofi-aventis U.S., Inc.

Disclosures:

Amin: sanofi-aventis US Inc.: Honoraria, Speakers Bureau. Lin:sanofi-aventis US Inc.: Employment, Research Funding. Wiederkehr:sanofi-aventis US Inc.: Research Funding.
Incidence and Outcome of Venous Thromboembolism In Terminally Ill Cancer Patients In Palliative Care unit
Authors: Lee Na-Ri , Yhim Ho-Young , Song Eun-Kee , Yim Chang-Yeol , Kwak Jae-Yong
Published: October 2019

Abstract 4390

Background:

The relation between venous thromboembolism (VTE) and cancer is well recognized, and risk of VTE increases with disease progression. However, the information available about VTE in terminally ill cancer patients in palliative care unit (PCU) is limited. We evaluated the incidence, risk factor and outcome of VTE in terminally ill cancer patients in PCU.

Methods:

The clinical records of Chonbuk National University Hospital were searched for all patients with acute, symptomatic deep-vein thrombosis (DVT) and pulmonary embolism (PE) in PCU from April 2008 through July 2010.

Results:

A total of 220 patients were included in the study and the median survival after palliative care was 16 days. Ten patients (4.5%) were newly diagnosed with VTE in PCU and nine patients (4%) had a history of VTE. All ten patients presented with DVT and the sites included lower extremities (eight) and upper extremities (two). All patients had more than one risk factor: immobilizations in 6 patients (54%), tumor compression in 3 patients (27%), and central venous catheter in 2 patients (18%). After diagnosis, 7 patients received treatment with low-molecular weight heparin (LMWH) and 4 of them switched to warfarin. The median duration of anticoagulation was 26 days. Major bleeding was noted 2 patients but VTE-related death did not occur. The median survival after diagnosis of VTE was 28 days.

Conclusion:

The incidence of VTE in PCU was relatively low. All patients had one or more risk factors and DVT of lower extremities was most frequent. Although anticoagulation was acceptable treatment except bleeding risk, the risks vs benefits need to be counterbalanced. Further large scale studies are needed to address many of these issues.

Disclosures:

No relevant conflicts of interest to declare.
Oral Anticoagulation In Patients with Atrial Fibrillation. Long-Term Follow-up
Authors: Colorio Cecilia Claudia , Puente Dolores Patricia , Rossi Andrea Silvia , Pombo Gonzalo , Guevara Eduardo , Martinuzzo Marta , Forastiero Ricardo
Published: October 2019

Abstract 4392

Atrial fibrillation (AF) is the most common cardiac rhythm disorder and an independent risk factor for stroke. It′s prevalence in AF pts without oral anticoagulation (OA) is 1 to 12%. OA is recommended in all valvular AF pts and in non valvular AF pts associated with other risk factors for stroke (CHADS2 score >1).

Objective:

to evaluate characteristics, evolution and incidence of thrombosis and bleeding in pts with AF under OA for at least 3 months.

Methods:

we retrospectively analyzed 850 pts between Jan 2003 and Jan 2010.

Results:

the mean follow-up was 25 months (range 3–169). The features of the entire group are listed in the table below:

Minor bleeding was observed in 32.7% of the entire group (278/850) and major bleeding in 2.7% (23/850). Most of the major bleedings occurred at the gastrointestinal tract, and 53% of those pts presented INR <2 (8/15). Fatal bleeding (located at CNS) developed in 0.2% (2/850). Ten pts developed thrombosis during the follow-up period (1.17%); 50% of them with INR < 2.

Conclusion:

45% of the pts were older than 74 years and most of them disclosed valvular AF. Minor bleeding was 15.4%/year, major bleeding: 1%/year, and thrombosis: 0.42%/year, according to the current literature.

Disclosures:

No relevant conflicts of interest to declare.
Thromboprophylaxis In Women with Recurrent Pregnancy Loss and Thrombophilia Undergoing Fertility Treatments: An Observational Study
Authors: Makarian Liana , Stein Daniel , Keltz Martin , Varma Mala
Published: October 2019

Abstract 4396

Thromboprophylaxis in women with recurrent pregnancy loss and thrombophilia undergoing fertility treatments: an observational study.

Background

Several phase II studies have suggested a benefit of thromboprophylaxis in pregnant women with histories of recurrent pregnancy loss (RPL) with and without thrombophilia. Two recent phase III studies (ALIFE, SPIN) showed no benefit of thromboprophylaxis in women with RPL, but they were not designed to study women with thrombophilia or with 3 or more miscarriages. In addition, plasminogen activator inhibitor-1 (PAI-1) has been linked to RPL, but there are limited data on the use of thromboprophylaxis in pregnant women with PAI-1 and RPL. A mechanism of unexplained RPL is thought to be placental thrombosis. The patients with thrombophilia who undergo assisted reproduction procedures might be at an increased risk of thrombosis due to multiple gestations, ovarian hyperstimulation and hyperestrogenemia. These could contribute to fetal loss via placental thrombosis. There are limited data on the outcome of pregnant women with histories of RPL treated with assisted reproduction and thromboprophylaxis.

Methods

We performed a retrospective review of 31 cases of women of age 20 to 42 that were referred to the Hematology Department at Roosevelt Hospital over the period of five years (between April 2005 and March 2010) for an evaluation prior to undergoing fertility treatment. Aspirin 81 mg daily prior to in vitro fertilization and enoxaparin 40 mg daily upon confirmation of pregnancy or following embryo transfer was recommended for the majority of patients. Aspirin and enoxaparin were recommended for 21 patients; aspirin alone for 5; enoxaparin alone for 4; and no therapy for 1.

Baseline Characteristics of the Patients

Results

Fifteen out of 31 patients took aspirin and enoxaparin; 9, aspirin alone; 4, enoxaparin alone; and 3, no treatment. Sixteen patients had assisted reproduction with in vitro fertilization or intrauterine insemination; 4 received ovulation induction medications; 7 had natural pregnancies; 2 patients had pregnancies by unknown means.

Twenty-five patients (81%) conceived; 13 (42%) had term deliveries; and 1(<1%) had a pre-term delivery at 31 weeks. Five patients (16%) were pregnant at last follow-up. Seven patients (22%) miscarried. Six patients (19%) did not conceive.

Conclusion

Thromboprophylaxis was associated with a high pregnancy rate and a high live birth rate in women with RPL, many with thrombophilia including PAI-1, presenting for fertility treatment.

Disclosures:

No relevant conflicts of interest to declare.
Characterizing the Effects of NN1731 and rFVIIa In Severe Hemophilia Patients with a Poor Laboratory Response to In Vivo Dosing of rFVIIa 90 μ g/Kg
Authors: Brophy Donald F , Martin Erika J , Barrett John Christian , Kuhn Jan G , Nolte Melinda , Hedner Ulla , Ezban Mirella
Published: October 2019

Abstract 4414

Introduction:

A rFVIIa analogue (NN1731) with increased prothrombinase activity on the activated platelet surface relative to rFVIIa has been shown to result in a more rapid and less variable response in spiking experiments with hemophilia whole blood samples. In a recent pharmacokinetic study of rFVIIa in 10 non-bleeding hemophilia A and B patients who received a dose of 90 mg/kg rFVIIa, we noted that there were two divergent groups based on their laboratory response to rFVIIa. Study participants who achieved clot formation time determined by Hemodyne (FOT) or Rotational Thromboelastography (CT) < 15 min were noted to have a “rapid laboratory response”; conversely, those with a FOT and CT value ≥ 15 min were noted to have a “delayed laboratory response”. In order to determine whether the participants with a delayed laboratory response to rFVIIa 90 μ g/kg would have an improved response to higher doses of rFVIIa and to NN1731, additional blood samples were collected and spiked ex vivo.

Patients and Methods:

Blood samples from ten severe FVIII or FIX deficient patients were spiked with 1.28, 2.56, 3.84 μ g/mL rFVIIa (corresponding to 90, 180 and 270.

Disclosures:

Hedner: Novo Nordisk A/S: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Speakers Bureau. Ezban:Novo Nordisk A/S: Employment, Membership on an entity's Board of Directors or advisory committees, Research Funding.
Procoagulant Activity of Sulfated Polysaccharides
Authors: Dockal Michael , Knappe Sabine , Panholzer Erwin , Palige Michael , Ehrlich Hartmut J. , Scheiflinger Friedrich
Published: October 2019

Abstract 4419

BAX513, a Laminaria japonica-derived fucoidan and other non-anticoagulant sulfated polysaccharides (NASPs) have been shown to improve clotting in FVIII- and FIX-deficient plasma (Liu et al. Thromb Haemost 2006; 95:68). In this study we assessed the procoagulant activities of fucoidans derived from a variety of brown sea algae species, and correlated the activity with molecular weight (MW) and degree of sulfation. Highly purified fucoidan preparations were studied in FVIII-inhibited whole blood by tissue factor-triggered thromboelastography (TEG). The procoagulant activity was characterized by calibrated automated thrombography (CAT) in FVIII- and FIX-deficient plasma and in combination with established hemophilia therapeutics. A dilute prothrombin time assay based on tissue factor pathway inhibitor supplementation (TFPI-dPT) was used to demonstrate the dose-dependent TFPI-inhibiting effect of BAX513 (EC50 = 0.18 ± 0.03 μ g/mL) in FVIII-deficient plasma. TEG in normal and FVIII-inhibited blood showed a dose-dependent procoagulant effect of most compounds where the optimal concentrations (1-100 nM) were dependent on the MW of the fucoidan. In FVIII-inhibited blood BAX513 at concentrations of ~10 nM (1.2 μ g/mL) completely normalized the TEG parameters. In contrast to sulfated fucoidans, undersulfated fucoidan hardly affected thrombin generation (TG). By CAT, the procoagulant window of NASPs in hemophilic plasma spanned more than two orders of magnitude with maximum effects being equivalent to (mU/mL) 730–940 FVIII, 32–80 FIX and 590–1230 FEIBA. NASPs combined with FVIII, FEIBA or FVIIa had an additive procoagulant effect. The optimal selection of molecular characteristics of NASPs will support the development of alternative hemophilia therapies.

Disclosures:

Dockal: Baxter Innovations GmbH: Employment. Knappe:Baxter Innovations GmbH: Employment. Panholzer:Baxter Innovations GmbH: Employment. Palige:Baxter Innovations GmbH: Employment. Ehrlich:Baxter Innovations GmbH: Employment. Scheiflinger:Baxter Innovations GmbH: Employment.
No Evidence of Cis-Acting SNPs In Immune Response Genes Previously Associated with Factor VIII Inhibitors: The San Antonio Family Heart Study
Authors: Howard Tom E. , Viel Kevin R. , Drigalenko Eugene , Cole Shelley , Epstein Melinda , Carless Melanie , Hughes Richard , Kim Benjamin , Dyer Tom , Pratt Kathleen P. , MacCluer Jean W. , Curran Joanne E. , Johnson Matthew P. , Moses Eric K. , Blangero John , Almasy Laura , Göring Harald
Published: October 2019

Abstract 4422

Background/Aims:

FVIII gene (F8) mutation type is a risk factor for FVIII inhibitors, which develop in ~20-30% of hemophilia A patients following FVIII replacement therapy. Studies have investigated immune response genes to determine why FVIII is immunogenic in some, but not all, patients with the same F8 abnormality. While some studies have found associations between inhibitor status and promoter polymorphisms in CTLA4, TNFA, and/or IL10, others have not. If these promoter polymorphisms influence inhibitor development, their alleles could modulate transcription initiation rates. The goal of this study was to investigate cis-acting genotype-specific differences in mean steady state mRNA levels.

Method:

We examined the relationship of lymphocyte CTLA4, TNFA, and IL10 mRNA levels with the genotypes of 49 SNPs located across their structural loci in 1189 Mexican American participants of the San Antonio Family Heart Study (SAFHS). Expression profiles were generated using Illumina's HWG-6 BeadChips and genotypes came from the Illumina Human HapMap 550 SNP panel. Measured genotype association analyses that accounted for non-independence of family members and employed an additive model were performed using the software package SOLAR.

Result:

Except for C(-13780)A, located upstream of CTLA4, which was modestly associated with CTLA4 mRNA levels (p<0.005), we observed no cis-acting regulatory variants associated with these genes’ transcription levels.

Conclusion:

We observed little evidence for cis-regulation of CTLA4, TNFA, and IL10 in Mexican Americans. It is possible that cis-acting functional variants are rare and not well-represented by the common GWAS SNPs used for these analyses. Because previously implicated polymorphisms were not included in this analysis and linkage disequilibrium patterns between markers are population-specific, we are currently genotyping these SNPs in the SAFHS.

Disclosures:

No relevant conflicts of interest to declare.
Successful Peripheral Haematopoitic Autologous Stem Cells Transplants After More Than 5 Days of without Cryopreservation In Non Hodgkin Lymphoma: Asian Scenario
Authors: Jasuja Sandeep , Malhota Hemant , Kukar(Jasuja) Neetu , Gautam Dinesh , Sharma Shrikant , Sharma Rajesh
Published: October 2019

Abstract 4447

Background:

Methods to simplify the stem cell transplantation procedure are the need of the hour in developing countries due to constraints of affordability and the large number of eligible patient for transplantation. Unprocessed leukapheresed material is useful to restore hemopoiesis after high dose chemotherapy and, in addition to being significantly less expensive, it also avoids the toxicity of cryopreservation (DMSO).

Method:

Over a period of 18 months (January 2009 to June 2010) in a hospital setting, we prospectively performed auto transplants in 5 relapsed/resistant non-Hodgkin's lymphoma patients using non-cryopreserved (stored for 5–8 days at 4°C) and un-manipulated peripheral blood stem cells mobilized by GCSF (10mg/kg/day) and GMCSF (5mg/kg/day) using a 5–7 day conditioning regimen. Viability of stem cells was checked daily by trypen blue and the cell were reinfused cells when viability comes down to less then 80% (minimum 5 days) or on day 8 which ever was earlier. The median collection of CD34+ stem cells was 2.8 × 106/cu mm (range 2–4.8 × 10 6/cumm)

Result:

The median time to achieve > 0.5 × 109/l granulocytes was 14 days. The median time to achieve > 20 × 109/l platelets was 16 days. CR was achieved in 4 cases. A very good partial response was achieved in 1 case. The 100-day mortality was zero. One patient, who was not in CR, died from relapse of the lymphoma, 9 months post transplant. The overall median post-transplant survival for other patients has not been reached. The approximate cost of the each graft was US$6,000.

Conclusion:

From this small series, we conclude that a simplified method to autograft patients avoiding purging procedures and cryopreservation of the cells is feasible. This technique helps avoid toxicity of DMSO and significantly decreases the cost of autologous hematopoietic stem cell transplant, perhaps in the world, an important issue in developing countries.

Disclosures:

No relevant conflicts of interest to declare.
Rapid Reduction of Chronic Myeloid Leukemia Stem Cells After Treatment with Second-Generation BCR-ABL Kinase Inhibitors, Dasatinib and Nilotinib
Authors: Minami Yosuke , Abe Akihiro , Nomura Yuka , Minami Miho , Kuwatsuka Yachiyo , Kitamura Kunio , Hiraga Junji , Mizuno Shinichi , Yamamoto Kazuhito , Kajiguchi Tomohiro , Sawa Masashi , Inagaki Yuichiro , Yokozawa Toshiya , Aoki Etsuko , Ozeki Kazutaka , Watanabe Keisuke , Miyamura Koichi , Kiyoi Hitoshi , Naoe Tomoki
Published: October 2019

Abstract 4457

Chronic myeloid leukemia (CML) is effectively treated with imatinib (IM), however, several mathematical models and ex vivo-examinations suggested that IM-therapy does not eradicate BCR-ABL-positive hematopoietic stem cells (HSC). We prospectively (0, 3, 6 and 12 months after IM-therapy) investigated 16 newly diagnosed and 22 long-term followed CML-chronic phase (CP) cases using methods previously reported (Jamieson et al., N Engl J Med, 2004. and Abe et al., Int J Hematol, 2008) (Figure 1) with FACSAria™ and quantitative RT-PCR of BCR-ABL among each sorted population; total mononuclear cells, HSC/Thy-1+, HSC/Thy-1–, common myeloid progenitors (CMP), granulocyte macrophage progenitors (GMP) and megakaryocyte erythroid progenitors (MEP). In optimal responders to IM-therapy, BCR-ABL transcripts in the HSC populations (HSC/Thy-1+ and HSC/Thy-1–) tended to be more retentive than other populations while gradual reduction was observed during the first 12 months in all populations. And discrepancy of minimum residual diseases (MRD) between the HSC populations and other populations was larger in patients after longer IM-therapy. In evaluating properties of CML stem cells and other markers, we observed irrelevant distribution of side population (SP) and expressions of ABC transporters (ABCB1 and ABCG2) in comparison with CD34/38 expression. We also prospectively investigated BCR-ABL transcripts in each population of 23 IM-resistant or -intolerant CML-CP cases and one newly diagnosed CML-accelerated phase (AP) case during treatment with second-generation tyrosine kinase inhibitors (2nd TKIs), dasatinib or nilotinib. Treatment with each inhibitor induced more rapid reduction of BCR-ABL transcripts even in the HSC population (CD34+CD38–) during the first 6 months and there was no significant difference of MRD among each population in optimal responders to 2nd TKIs-therapy. In the stromal co-culturing system using primary cells and leukemic NOD/SCID/IL2rgnull (NOG) mice xenotransplanted with Ph+ leukemia cells, retention of quiescent slow-cycling (Hoechst 33342low/Pyronin Ylow) CD34+ population after IM-treatment were observed and cell death mechanisms after treatment with 2nd TKIs are also under investigation. These results imply that therapy with 2nd TKIs could be a promising approach for quick and efficient reduction of the CML stem cells and cure of disease.

Figure 1 Figure 1.

Disclosures:

Naoe: Kyowa-Kirin: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding.
Regulation of c-Myc Expression through the Depletion of THAP11 and Fbw7 by Bcr-Abl Promotes CML Cell Proliferation
Authors: Yokota Daisuke , Nakamura Satoki , Takemura Tomonari , Nagata Yasuyuki , Hirano Isao , Ono Takaaki , Shigeno Kazuyuki , Fujisawa Shinya , Ohnishi Kazunori
Published: October 2019

Abstract 4463

[Background and Aims]

In various signaling pathways activated by Bcr-Abl, c-Myc promotes the Bcr-Abl transformed cell proliferation through activated Akt, Jak2 and NF-κB. We have previously shown that Bcr-Abl represses the expression of THAP11 and continuously expressed c-Myc, resulting in the proliferation of CML cells. However, the mechanism of c-Myc regulation is unclear in CML cell proliferation. In the present study, we investigated the mechanism of c-Myc transcription regulation in the Bcr-Abl+ progenitor cells derived from CML patients.

[Methods]

The cells used in this study were human CML cell lines, K562, Meg01 and SHG3 cells. Primary CML cells (ALDHhi cells) were obtained from the bone marrow of CML (CP) patients (n=12). Human normal ALDHhi cells were isolated from bone marrow of healthy volunteers after obtaining informed consents. For analysis of THAP11 mRNA expression, quantitative RT-PCR was performed in all cell lines treated with Abl kinase inhibitors (STI571, AMN107, and BMS354825). For cell survival analysis and the levels of c-Myc, Fbw7 and some CDKIs in CML cells, MTT assays, western blot and cell cycle analysis were performed in all cell lines transfected with THAP11 siRNA or cDNA. For colony analysis, the colonies of CFU-GEMM, CFU-GM, and BFU-E were counted in CML stem/progenitor cells transfected with THAP11 siRNA or cDNA, or treated with Abl kinase inhibitors.

[Results]

In CML cell lines, the expressions of THAP11 mRNA and protein were significantly increased by treatment with Abl kinase inhibitors or transfection with Bcr-Abl siRNA. In CML cells transfected with the THAP11 cDNA, it is shown that CML cell proliferation was inhibited, and the expression of c-Myc protein was decreased compared to the untransfected cells. In addition, the inhibition of Bcr-Abl by the Abl kinase inhibitors or depletion of Bcr-Abl induced the expression of Fbw7 in CML cells. In CML stem/progenitor cells (ALDHhi cells) obtained from patients with CML, the expression of THAP11 mRNA was suppressed, and the transfection with Bcr-Abl siRNA or treatment with Abl kinase inhibitors increased the expression of THAP11 and Fbw7. In CFU-GEMM, CFU-GM, and BFU-E, treatment with the Abl kinase inhibitors and depletion of Bcr-Abl induced the THAP11 and Fbw7 expression and reduced the c-Myc expression, and inhibited colony formation of Bcr-Abl+ progenitor cells.

[Conclusion]

In CML cells, we found that the depletion of THAP11 and Fbw7 expression. We showed that Bcr-Abl induced the expression of c-Myc by depletion of THAP11 and also inhibited the degradation of c-Myc by depletion of Fbw7. This study showed that Bcr-Abl promoted the CML cell proliferation through the THAP11 and Fbw7 mediated-c-Myc aberrant expression.

Disclosures:

No relevant conflicts of interest to declare.
Are CML Lymphoid Blast Crisis and Ph Positive ALL Genomically Indistinguishable?
Authors: Grace Colin , Nacheva Elisabeth P
Published: October 2019

Abstract 4464

Philadelphia positive malignant disorders are a clinically divergent group of hemoblastoses with a unique identifying feature, the BCR/ABL1 fusion gene, usually resulting from the chromosome rearrangement t(9;22)(q34;q11) or its variants, that leads to constitutive expression of an aberrant tyrosine kinase. These include chronic myeloid leukaemia (CML) and de novo acute leukaemia of both myeloid Ph(+)AML and lymphoid origin Ph(+)ALL. The latter two disorders are clinically aggressive and therapy challenging even in the era of the powerful tyrosine kinase inhibitors. CML is a multistage progressive disease, which if untreated, inevitably ends as fatal acute leukaemia, either myeloid or lymphoid. The latter is often thought to be indistinguishable from Ph(+)ALL, the most common type of ALL in adults. We have identified DNA sequences the imbalances of which appear to be significantly associated with the disease stage and lineage origin in CML and Ph(+)ALL samples. We used array CGH at a resolution of ~2kb to explore hot spot regions obtained from 102 patient samples comprising 92 CML and controls together with 10 Ph(+)ALL and show how Significance Analysis of Microarrays (1) can be used to identify differences in the genome profile of de novo Ph(+)ALL and lymphoid blast transformation of CML. We show that lymphoid blast crisis CML differs significantly from Ph(+)ALL not only due to the presence of 9p deletions but also due to genomic gains in other chromosomes. Furthermore we identify a sub group of Ph(+)ALL with a distinctive genomic profile. Having identified genome regions of potential interest, ranked in order of significance, out of the 100's of thousands of array results, it is then a challenge to design further experiments to evaluate their contribution to the biology of the BCR/ABL positive disease.

1 Tusher V, Tibshirani R, Chu G: Significance analysis of microarrays applied to the ionizing radiation response. Proc Natl Acad Sci U S A 98:5116-5121 (2001).

Disclosures:

No relevant conflicts of interest to declare.
G2/M Arrest Sensitizes Chronic Myelogenous Leukemia Cells to TRAIL-Induced Apoptosis
Authors: Devlin David , Szegezdi Eva , Tanja Paavilainen , Orosz Orsolya , O'Dwyer Michael , Carty Michael , Samali Afshin , Hennequart Séverine Cruet
Published: October 2019

Abstract 4465

The death ligand, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receives great interest as it targets and kills cancerous cells, but not non-transformed cells. While it is in phase I/II clinical trials for a range of solid tumours, the generally low sensitivity of leukemia cells to TRAIL makes it a less attractive therapeutic for these cancers.

We found that doxorubicin and cytarabine, agents that induce DNA damage and impair cell cycle progression, can sensitize CML cells to TRAIL with CI<1 at Fa of ED25 and ED50 (based on median-effect method using the isobologram equation). Inhibition of the cell cycle checkpoint kinases Chk1/2 with UCN-01 did not influence TRAIL-induced apoptosis nor could it abolish the sensitizing effect of doxorubicin. Interestingly, inhibition of Ataxia Telangiectasia Mutated (ATM), a key DNA damage response kinase, with KU-55933 induced a G2/M arrest and enhanced TRAIL-induced apoptosis. Inhibition of ATM alone induced 22±3.1% apoptosis and increased TRAIL-induced apoptosis from 27.2±4.7% to 68±7.2%. Cell cycle analysis revealed that while the proportion of cells in the G0/G1 and S phases slightly increased, the proportion of the cells in the G2/M phase dropped by 31.6±3.2% (p<0.05) indicating that G2/M arrested cells were more sensitive to TRAIL than cells in G0/G1 and S phases. TRAIL-induced CML cell death was also synergistically enhanced by arresting the cells in G2/M using the microtubule disrupting drugs, nocodazole or colcemide. Cells were treated with a concentration of nocodazole or colcemide that induced above 90% G2/M arrest for 16 h (0.3 mM and 0.1 mg/ml, respectively) followed by treatment with 250 ng/ml of TRAIL for 24 h. Nocodazole, colcemide and TRAIL individually induced 19±3.7% 26.3±4.4% and 27.2±4.7% cell death, while combination of nocodazole or colcemide with TRAIL resulted 89±6.8% and 93±5.9% cell death, respectively. In summary, we found that induction of DNA damage sensitizes CML cells to TRAIL and that TRAIL-sensitivity of CML cells is cell cycle-dependent.

Disclosures:

O'Dwyer: Novartis: Honoraria.
Clinical Relevance of Vascular Endothelial Growth Factor Type A (VEGFA) and VEGF Receptor Type 2 (VEGFR2) Gene Polymorphism In Chronic Lymphocytic Leukemia
Authors: Gora-Tybor Joanna , Jamroziak Krzysztof , Szemraj Zofia , Szemraj Janusz , Lech-Maranda Ewa , Grzybowska-Izydorczyk Olga , Oszajca Katarzyna , Giannopoulos Krzysztof , Robak Tadeusz
Published: October 2019

Abstract 4467

Vascular endothelial growth factor type A (VEGFA) is a key regulator of angiogenesis and vascular permeability. Given that chronic lymphocytic leukemia (CLL) cells secrete VEGFA, express VEGFA receptors and circulate in blood with increased VEGFA level it is likely that VEGFA-mediated signaling may influence CLL clone survival. In this case-control study we verified the hypothesis that inherited differences in activities of VEGFA and its main receptor in CLL, vascular endothelial growth factor receptor type 2 (VEGFR2, also known as kinase insert domain-containing receptor/fetal liver kinase-1, Flk/1/KDR) impact predisposition to CLL or the course of the disease. Four functional single nucleotide polymorphisms (SNPs) including two SNPs in VEGFA gene, namely +405G>C (rs2010963) and +936C>T (rs3025039) and two SNPs in VEGFR2 gene, namely -271G>A and +1719A>T (rs1870377) were genotyped using PCR-based assays in 175 Caucasian CLL patients and 133 ethnically, geographically, age and sex matched controls. The minor allele frequencies in CLL patients were found as follows: 0.36 for +405C VEGFA allele, 0.17 for +936T VEGFA allele, 0.46 for -271 VEGFR2 allele and 0.35 for +1719A VEGFR2 allele. The genotype and allele frequencies of all tested SNPS in VEGFA and VEGFR2 genes did not differ significantly between cases and controls (p>0.05). No genotype or allele was significantly associated with important prognostic factors in CLL including clinical stage, IgVH mutational status, ZAP-70 expression and FISH cytogenetic abnormalities. Furthermore, the carriers of different VEGFA and VEGFR2 genetic variants had comparable time to CLL treatment initiation. In conclusion, the results of our study do not support major involvement of genetic polymorphisms in VEGFA mediated pathway in susceptibility to CLL or its outcome.

Disclosures:

Robak: GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Genmab: Consultancy, Research Funding; Roche: Consultancy, Honoraria, Research Funding.
Sustained Complete Molecular Response (CMR) with Interferon-alpha Maintenance After Induction with Imatinib In Chronic Myeloid Leukemia (CML) Patients.
Authors: Carella A. M. , Catania G. , Pica and G. Beltrami G.
Published: October 2019

Abstract 4486

Cytotoxic lymphocytes (CTLs) which recognize distinct antigenic peptides on CML cells, contributed greatly to the cure after allografting. Previously, BCR-ABL specific peptides and the PR1 non-apeptide, were found to elicit a CML-specific CTL response (Molldrem, 1996/1997; Bocchia 1996, Clark 2001). PR1 is a peptide derived from myeloblastin (MBN), also known as proteinase 3. MBN is abundantly expressed in azurophil granules of normal myeloid cells and is substantially overexpressed in certain immature myeloid leukemia cells where it may be important for the maintenance of a leukemic phenotype. PR1-specific CTLs (PR1-CTLs) lyses and inhibits the proliferation of CML cells but not of normal myeloid precursors. The association between the emergence of PR1-CTLs and the response to IFN-a in vivo strongly implied that IFN-a can induce remissions via induction of a CML-specific PR1-CTLs response (Molldrem et al, 2000).

Recent data demonstrating a failure of IM to kill cell cycle-arrested CML precursors advice us to be attentive to arising escape mechanisms of even chronic phase CML; therefore IFN-a, given to CML patient with undetectable disease achieved with IM, might enable its discontinuation.

We have treated until now 8 CML patients who achieved stable CMR for at least one year after IM therapy. These patients discontinued IM and started IFN-a at the dose of 3–9 M/U/m2 weekly (median 6 M/U/m2). The median duration of IM therapy was 60 (range, 31–76) months before IM discontinuation. At a median follow-up of 16 months (range, 9–24 months) after discontinuation of IM, five patients still have an undetectable level of BCR-ABL transcript under IFN-a. Grade 2 intolerance (muscle pain, fever) to IFN-a developed in 5/8 patients. The details of patients characteristics will be discussed during the presentation. These preliminary results demonstrate that treatment with low dose IFN-a in CML patients with undetectable disease is feasible and this approach may become an attractive alternative to lifelong TKI therapy.

Disclosures:

No relevant conflicts of interest to declare.
Extensive Pleural and Pericardial Effusion In 4 CML Patients Treated with Dasatinib at 100 Mg or 50 Mg Once Daily.
Authors: Krauth Maria-Theresa , Herndlhofer Susanne , Schmook Maria-Theresa , Mitterbauer Gerlinde , Schloegl Ernst , Valent Peter
Published: October 2019

Abstract 4496

The multikinase BCR/ABL inhibitor dasatinib exerts major growth-inhibitory effects in imatinib-resistant patients with chronic myeloid leukemia (CML). Although previously reported to be a well-tolerated drug, several side effects such as pleural and pericardial effusion have been reported at a dose of 140 mg daily. Therefore, the approved standard dose of dasatinib was reduced to 100 mg daily. More recent data suggest that freshly diagnosed patients with CML treated with dasatinib at 100 mg once daily may still develop pleural effusions, but the frequency of this side effect was reported to be lower compared to patients receiving 140 mg daily dasatinib. Moreover, effusion formation was reported to be less severe, with almost no grade 3/4 events, in patients receiving 100 mg daily dasatinib. We examined a cohort of CML patients (n=13) treated with dasatinib at 100 mg or 50 mg daily, for development of severe non-hematologic side effects. Patients received dasatinib for at least 3 months (range: 3–38 months; observation period: March 2005 to June 2010). Of these 13 patients, 4 had previously received 140 mg dasatinib daily. In all 4 patients, the dose of dasatinib was reduced to 100 mg or 50 mg daily because of effusion formation. In the other 9 patients, the initial dose of dasatinib was 100 mg daily. Of these 9 patients, 2 patients in chronic phase (CP) received dasatinib as frontline therapy. Four of our 13 patients developed severe effusions (grade 3/4) while on dasatinib at 100 mg or 50 mg daily, including one CP patient receiving dasatinib as frontline therapy. In two patients, massive pleural effusions were recorded, and two developed pericardial effusion together with pleural effusions. In two patients, effusion formation required paracentesis and surgical intervention. No pre-existing cardiac or pulmonary diseases were known in these 4 patients. In 3 patients, dasatinib had to be discontinued despite treatment with low dose glucocorticosteroids and diuretics. After switching to an alternative BCR/ABL inhibitor, no further effusion formation occurred. In summary, dasatinib-treated patients are at risk for the development of pleural and pericardial effusions even when the drug is administered at a dose of 100 mg or 50 mg daily. Therefore, all patients should be examined carefully for pre-existing relevant comorbidities and cardiovascular risk factors before dasatinib is started, and all patients should have repeated chest × ray controls during long-term treatment with dasatinib.

Disclosures:

Valent: Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding.
Imatinib Mesylate (IM) Versus IM + Low Dose of Pegylated Interferon Alfa 2a (Peg-IFN 2a) In Newly-Diagnosed Chronic-Phase (CP) Chronic Myeloid Leukemia (CML).
Authors: Meillon Luis Antonio , Campos-Cabrera Salvador , Delgado-Lopez Nancy , Fernandez-Martinez Angel A. , Medrano-Contreras Jesus , Gutierrez Guillermo , Perez-Rocha Juan F. , Terreros-Muñoz Eduardo , Gomez-Cortes Sue C. , Guerrero-Rivera Susana , Nacho-Vargas Kevin A.
Published: October 2019

Abstract 4497

Background:

IM 400mg daily is the current standard of treatment of CP CML. Almost 70% of patients achieve complete cytogenetic response (CCR) at 12 months (mo) (IRIS Trial) and the rate of Major Molecular Response (MMR) is 40% with IM 400mg daily (TOPS Trial). On the other hand, low doses of Peg-IFN 2a has the same efficacy and lower toxicity profile and cost as high dose, mainly when it is combined with other drugs (MRC and Hovon groups, Blood 2004; 103:4408). Combination of IM + Peg-IFN 2a or Cytarabine could increase the rate of response in CML.

Aims:

To evaluate the rates of CCR and MMR at 12 mo in Mexican patients with newly-diagnosed CP-CML treated with IM versus IM + Peg-IFN 2a.

Methods:

Between 2006 and 2008, 10 patients were randomized 1:1 and stratified by Sokal and Hasford risk groups. Cytogenetic and Molecular assesments were available for all patients. In the arm A of the study IM 400 mg daily was delivered. In the Arm B IM + Peg-IFN 2a was delivered at 400 mg daily + 90 μ g per week respectively. Peg-IFN 2a was started in the 7th week of treatment (Hochhaus A, et al ASCO 2003. Abstract #2287).

Results:

For this initial report, 10 patients were analyzed, median age was 35 years (25-55), 50% males; Sokal score was: low risk 70%, and high risk 30%. Hasford score was: low risk 40%, intermediate 30% and high risk 30%. All patients are alive with a median follow-up of 41 mo (30-48). CCR at 12 mo was obtained in 80% in both arms of treatment. MMR was obtained in 10% in patients with IM alone and 30% in patients with IM + Peg-IFN 2a. Overall the rate of primary resistance was 10% and the rate of suboptimal response was 10%. IM 400 mg was well tolerated. Peg-IFN 2a was tolerated in most patients, but needed discontinuation because increased cytopenias or other non hematologic toxicities. The median time of duration of treatment with Peg-IFN 2a was 6 mo (3-12).

Conclusions:

IM 400 mg and IM 400 mg + Peg-IFN 2a obtained similar rates of CCR. IM 400 mg + Peg-IFN 2a obtained a higher rate of MMR. The combination of IM 400 mg + Peg-IFN 2a is feasible. There is a slight increase in toxicity with this combination. Further follow-up is warranted for these patients.

Disclosures:

No relevant conflicts of interest to declare.
Clinical Outcome of CML Patients with Philadelphia Chromosome Complex Variants.
Authors: Castillo Santiago del , Delgado Regina Garcia , Entrena Laura , Hernandez Agustin M , Campos Arturo , Duarte Jose , Gallardo Ana I , Sanchez Guacimara , Cerda Maria , Ramirez Gema
Published: October 2019

Abstract 4499

INTRODUCTION:

The presence of translocation between chromosomes 9 and 22 that characterizes the chronic myeloid leukemia (CML) is occasionally accompanied by more complex variations involving additional exchange of genetic material with other chromosomes. This variants of Philadelphia chromosome have no worse prognosis than those others with the common translocation.

MATERIAL:

Since 1997 we have diagnosed in our hospital 5 CML patients who didn't show any of these variants. Three women 17, 23 and 76 years old and two men of 36 and 65. All of them diagnosed in chronic phase. Risk stage at diagnosis by Sokal were 1 high, 1 intermediate and 3 low. By Hasford 2 were intermediate end 3 low.

Philadelphia chromosome variants involve a third chromosome in 4 cases (translocations 2;9;22, 9;22;12, 9;22;9 and 6;9;22) and in one case involving four chromosomes (translocation 1;2;9;22).

Three patients diagnosed before the imatinib approval started treatment with IFN and Ara-C and subsequently changed to Imatinib treatment. Two others started treatment with imatinib directly.

RESULTS:

All patients had a good outcome with treatment being the current state of 2 patients in complete molecular response (105 and 60 months of follow-up) and 2 patients in Major Molecular Response (146 and 143 months). The 5th patient, a 17 years old woman, has been treated for three months with Imatinib and showed complete haematological response at first month and major cytogenetic response at third month. It is striking in this last patient the fact that two years earlier had been referred for study of myeloid moderate leukocytosis (20,000 leukocytes with circulating myeloid progenitors without anemia, thrombocytosis, or splenomegaly). The patient didn't come to clinic when Bone Marrow Test was cited and two years later resumes the visit continuing with the same leukocytosis in peripheral blood and without splenomegaly unchanged despite not having received any treatment.

CONCLUSION:

Our experience confirm that this type of patients with complex translocation variants have no worse prognosis than normal translocation under imatinib treatment and suggests that may have a more benign clinical behavior.

Disclosures:

No relevant conflicts of interest to declare.