bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact Assessment of Immunogenicity of Romiplostim In Subjects with Immune Thrombocytopenic Purpura (ITP)
Authors: Pamma Rupinderjit , Deshpande Meghana , Hokom Martha , Gupta Shalini , Zhuang Yao , Chirmule Naren , Swanson Steve , Jawa Vibha 
Published: October 2019

Abstract
Abstract 2517
Romiplostim is a peptibody that increases platelet production via binding to the thrombopoietin (TPO) receptor. This molecule has been engineered to have no amino acid sequence homology to endogenous TPO (eTPO); however, a low theoretical risk of developing conformational antibodies that cross-react with eTPO does exist. The current immunogenicity assessment strategy detects antibodies that bind to romiplostim, TPO, or TMP (the active peptide portion of romiplostim) and identifies any antibodies capable of neutralizing the biological effect of the drug or TPO.
In clinical studies, 537 subjects with ITP were dosed with romiplostim; 31 (5.8%) subjects developed binding antibodies to romiplostim and 21 (3.9%) subjects developed binding antibodies to TPO. However, only 2 (0.4%) of these subjects had antibodies that neutralized the biological effect of romiplostim. The binding antibodies detected against romiplostim were not cross-reactive with TPO in the immunoassay and did not neutralize TPO in the biological assay. Pre-existing binding antibodies against romiplostim were detected in 43 (8.0%) subjects and against TPO in 29 (5.4%) subjects. The immunogenicity rates in Japanese ITP subjects (n=46) dosed with romiplostim were comparable to non-Japanese subjects.
As a part of the post-marketing risk management strategy, Amgen performed immunogenicity testing on 37 subjects. Of these subjects, 3 developed binding antibodies against romiplostim that were not cross-reactive with TPO. None of these subjects developed neutralizing antibodies to romiplostim or TPO.
The impact of immunogenicity to romiplostim on safety and efficacy was evaluated utilizing platelet profile as a pharmacodynamic marker. No significant impact of the antibodies against romiplostim and TPO on the development of adverse events was noted. Grade 3 and above hypersensitivity related events were found in subjects that were antibody-positive and antibody-negative in the same proportion, indicating that these events were not related to anti-romiplostim or anti-TPO antibodies. No clinical correlation could be made between the development of antibodies against romiplostim and/or against TPO and the previous drug therapies or concomitant medications. No correlation between binding antibodies to romiplostim or TPO and platelet profiles of these subjects could be established. The subjects that developed a neutralizing antibody response against romiplostim were associated with a trend of lower platelet counts. The reduced platelet counts could be attributed to the presence of binding and neutralizing antibodies to romiplostim. Alternatively, the lowering of the platelet counts could also be attributed to discontinuation of therapy at the end of study.

Disclosures:
No relevant conflicts of interest to declare.
Decreasing Adverse Events From Warfarin In a Community Hospital Setting
Authors: Jubelirer Steven J , Davis Elaine A , Hodges Brian , Morris Lillian D , Miller Karen S 
Published: October 2019

Abstract
Abstract 2554

Background:
Millions of patients across the USA received warfarin to prevent and treat thromboembolism each year. Despite its effectiveness warfarin is associated with a risk of bleeding. The Joint Commission has brought attention to the safety of warfarin and challenged hospitals to “reduce the likelihood of harm associated with the use of anticoagulation therapy” as one of two new national patient safety goals for 2008. At CAMC (Charleston Area Medical Center, Charleston, WV) an anticoagulation safety task force was formed to address this challenge.

Purpose:
This study was initiated to document and reduce harm from warfarin at CAMC.

Methods:
This is an ongoing retrospective review of inpatients that received warfarin and had an INR of ≥4.0. Variables collected included, INR values, warfarin administration (dose and frequency), comorbidities, other current medications, other laboratory values, harm level (as defined by the Institute for Healthcare Improvement), presence of major or minor bleeding, use of blood transfusions, fresh frozen plasma, or vitamin K (and dose).

Results:
During baseline period there was a 3 month average of 15.86 episodes of harm/1000 warfarin doses while post implementation 9.69 episodes of harm were noted. At baseline, of those with harm 83.7% were temporary harm in which patients required an intervention (FFP or vitamin K) and 30.2% of the critical INR's occurred when warfarin was ordered daily instead of after the result was obtained and reviewed by the physician. From baseline April-July 08 compared to Aug 08-Feb 09 the frequency of vitamin K administration for INR < 5 and no bleeding has decreased by 33% (p=0.144). Overall there were 4.15% critical INR's before compared to 0.88% after implementing improvements representing a 79% improvement.

Conclusions:
Baseline data suggested a need for improvement in the safety of warfarin. Implementation of education, order sets (warfarin administration, warfarin reversal, physician pocket cards, and inpatient to outpatient handoff order sets, and warfarin workflow) and drug/drug interaction alerts to reduce adverse events. This study showed a decrease in the episodes of harm and the percent of critical INR's. It is estimated that the annual cost savings (RN time to treat critical INR's, excluding nursing time to administer vitamin K, and length of stay from complications of treatment) was $50,445.

Disclosures:
No relevant conflicts of interest to declare.
Gi-Coupled GPCR Signaling Is Required at Multiple Levels and In Different Lineages In Hematopoiesis.
Authors: Terpager Marie , Kataoka Hiroshi , Cornelissen Ivo , Coughlin Shaun R. 
Published: October 2019

Abstract
Abstract 2635
G protein-coupled receptors (GPCRs) can regulate cell migration, survival, proliferation and differentiation –– key processes in hematopoiesis. The Gi-coupled receptor CXCR4 plays a key role in hematopoiesis, suggesting that related receptors might also contribute. Because all Gi family members except Gz are inhibited by pertussis toxin (PTX), we utilized a ROSA26-CreOnPTX mouse line that expresses PTX in a Cre-dependent manner to broadly probe the role of Gi signaling in hematopoiesis. Mice hemizygous for the hematopoietic lineage-specific Cre transgene Vav-iCre were crossed with ROSA26-CreOnPTX/CreOnPTX mice to generate offspring expressing PTX in hematopoietic lineages (Vav-PTX) and Cre-negative controls in which the PTX allele remained silent. Vav-PTX mice were born at the expected Mendelian rate, and except for a smaller thymus, were grossly normal, but all died with pneumonia between days 2 and 14. Bone marrow in 3 day-old Vav-PTX mice was hypocellular with significant underrepresentation of granulocytic and lymphocytic lineages as well as hematopoietic stem and progenitor cells (lin-, c-kit+, Sca1+). In bone marrow reconstitution studies, cells from Vav-PTX fetal livers (E14.5) showed impaired short-term and no long-term repopulating activity. Additionally, Vav-PTX fetal liver cells were significantly impaired in their ability to form granulocyte/macrophage and erythroid colonies in vitro. Interestingly, when wild-type E14.5 fetal liver cells were grown in vitro in presence of exogenous PTX, only erythroid colony formation was impaired, and flow cytometric analysis of the progenitor populations of Vav-PTX fetal liver revealed a significant decrease in granulocyte-macrophage progenitors (GMPs) as well as in common myeloid progenitors (CMPs) but not in megakaryocyte/erythroid progenitors (MEPs). Thus, reduced progenitor populations may account for reduced granulocyte/macrophage colony-forming activity in fetal liver cell cultures but does not account for reduced erythroid colony-forming activity. Indeed, normal MEP numbers in Vav-PTX livers and the ability of exogenous PTX to inhibit formation of erythroid colonies in wild-type fetal liver cultures suggests that Gi signaling in MEPs or their progeny may contribute to erythropoiesis in fetal liver. Several of the necessary roles of Gi signaling identified above are not accounted for by the function of CXCR4, and, taken together, our data suggest that Gi-coupled GPCRs likely contribute to hematopoiesis at multiple levels and in different lineages. An effort to identify GPCRs that contribute to erythropoiesis is underway.

Disclosures:
No relevant conflicts of interest to declare.
Alterations In HLA-DR Expression In Peripheral Blood Mononuclear Cells Are Associated with An Elevated Tricuspid Regurgitant Jet Velocity and Pulmonary Hypertension of Sickle Cell Disease
Authors: Klings Elizabeth , Dworkis Daniel A , Safaya Surinder , Li Guihua , Reid Lynda , Sebastiani Paola , Baldwin Clinton T. , Steinberg Martin H. 
Published: October 2019

Abstract
Abstract 2640
Sickle cell anemia (SCA) is characterized by a chronic inflammatory vasculopathy. An elevated tricuspid regurgitant jet velocity (TRV) by echocardiography in SCA patients is not only reflective of possible pulmonary hypertension but is also associated with increased mortality risk, relative systemic hypertension, and renal disease, all of which suggest this is a marker of a more diffuse vasculopathy. We hypothesized that differential gene expression in peripheral blood mononuclear cells (PBMCs) occurs in SCA patients with an elevated TRV and might reflect the role of inflammation in sickle vasculopathy. Peripheral blood samples were obtained from 15 steady-state SCA patients (7 of whom had a TRV > 2.5 m/sec). Three cases with increased TRV had right heart catheterization that confirmed the presence of pulmonary hypertension. PBMCs were isolated via a Ficoll separation. RNA was isolated and amplified using the Ambion Illumina Total RNA Prep Kit, and then hybridized to Illumina Human HT-12 V3 Expression Bead Chips and scanned. Expression data was background corrected, log-transformed, and strictly filtered to consider only probes showing expression in each sample and significant expression in at least half of either group of samples. Differential expression was tested for significance using a t-test performed on both native and rescaled datasets, and only probes reaching a significance of p < 0.05 in both datasets were considered further. Of the 50 probes selected as significant in this way, the two of the most interesting were HLA-DRB1 and MYOM2, observed almost exclusively in SCA patients with a normal echocardiogram (p=0.007 and 0.008 respectively). Differential PBMC gene expression across the HLA-DRB1 locus has been associated in other populations with impaired immunity and increased susceptibility to sepsis. Our previous genetic studies have identified a potential link between the HLA loci and leg ulcers, another hemolytic complication associated with an elevated TRV in 219 SCA cases when compared with 1180 controls. In those studies, HLA-B was found to be in linkage disequilibrium with 3 genes found to be significantly associated with leg ulcers. This suggests the possibility that these heritable loci may play a role in disease modulation in SCD. PBMCs in SCA patients might have a pro-inflammatory phenotype and this may play a role in the vasculopathy and increased mortality risk observed in these patients.

Disclosures:
No relevant conflicts of interest to declare.
Improvement In Acute Management of Vaso-Occlusive Pain In Pediatric Sickle Cell Disease with Use of a Clinical Pathway
Authors: Ender Katherine , Freed Jennifer , Babineau John , Tresgallo Mary , Schechter William , Saroyan John , Kharbanda Anupam 
Published: October 2019

Abstract
Abstract 2660

Background:
Sickle cell disease causes considerable morbidity and mortality. Three guidelines exist for the management of vaso-occlusive pain, although studies have shown that these guidelines are not well followed and that there is considerable variation in care. Investigations of clinical pathways for pediatric sickle cell pain have not been published to our knowledge, but research in other pediatric conditions has shown that the implementation of clinical pathways can improve medical care. We initiated an investigation of the effects of a pain management pathway for sickle cell vaso-occlusive crisis in the emergency department (ED) with the hypothesis that the introduction of a clinical pathway would improve the efficiency and efficacy of acute pain management.

Methods:
We conducted a prospective, cohort study from February 2009 to March 2010 in an urban, tertiary care ED. We collected data from patients aged 3–18 years old with sickle cell disease who presented to the ED with vaso-occlusive crisis (VOC) pain. Baseline data was collected for five months prior to the introduction of the clinical pathway, followed by a four-week time interval in which the ED physicians and nurses were in-serviced on the pathway, followed by six months in which data was collected with the clinical pathway in place. Our pathway, which is in checklist format with instructions for triage, monitoring, medication administration, and timing of assessments and interventions, was developed by representatives from the divisions of Pediatric Hematology, Pediatric Emergency Medicine, and Pediatric Pain Medicine, Symptom Management and Palliative Care and based upon current standard-of-care guidelines.

Results:
Over the eleven month study period, 68 patients were enrolled. Random chart audits revealed a 75% capture rate. Significant improvement was demonstrated in time interval to first analgesic from 74 minutes to 42 minutes (p value 0.02), time interval to first opioid from 94 minutes to 46 minutes (p value < 0.01), and time interval to subsequent assessment of pain score from 110 minutes to 72 minutes (p value 0.02). The percentage of patients who received ketorolac also increased from 57% to 82% (p value 0.03). Change in pain scores was not significantly different, nor was admission rate.

Conclusions:
Implementation of a pain management pathway for sickle cell VOC led to an improvement in the time interval to administration of first analgesic and time interval to pain re-assessment, bringing these aspects of patient management closer to accepted guidelines. Whether improvement can be made in admission rates, change in pain ratings, and patient satisfaction will require further study.

Disclosures:
No relevant conflicts of interest to declare.
Integrated Use of Minimal Residual Disease Classification and IKZF1 Alteration Status Accurately Predicts 79% of Relapses In Pediatric Acute Lymphoblastic Leukemia
Authors: Waanders Esmé , van der elden Vincent H.J. , van der Schoot Ellen , van Leeuwen Frank N. , van Reijmersdal Simon V. , de Haas Valerie , Veerman Anjo J. , van Kessel Ad Geurts , Hoogerbrugge Peter M. , Kuiper Roland P. , van Dongen Jacques J.M. 
Published: October 2019

Abstract
Abstract 272
The response to therapy as determined by minimal residual disease (MRD) is currently used for stratification in treatment protocols for pediatric acute lymphoblastic leukemia (ALL). Even though MRD classification clearly identifies patients at low or at high risk for relapse, it also results in a large intermediate group (50 to 60% of patients), which still contains approximately half of all relapse cases. To improve risk stratification, we evaluated the added value of the IKZF1 alteration status, recently identified as a prognostic factor, in precursor-B-ALL patients. In an unbiased cohort of 131 uniformly treated precursor-B-ALL patients, we determined MRD levels at 42 and 84 days after treatment initiation using RQ-PCR analysis of Ig/TCR rearrangements. Based on these levels, patients were divided into three groups: MRD-Low (MRD-L), MRD-Medium (MRD-M) and MRD-High (MRD-H). IKZF1 alterations at diagnosis were determined using multiplex ligation-dependent probe amplification and genomic sequencing. We confirmed the strong prognostic significance of MRD classification, which was independent of IKZF1 status. Importantly, in the large MRD-M group (n=81; 62% of patients) containing 46% of the relapsed patients, IKZF1 alteration status identified 8 out of 11 relapsed patients (72%). The 9 year relapse-free survival (RFS) for IKZF1 mutated patients in this MRD-M group was 27% compared to 96% for patients wild-type for IKZF1 (P<0.001). Based on these results, we defined a new parameter integrating both MRD and IKZF1 status. The favorable risk group included patients classified as MRD-L or MRD-M with IKZF1 wild-type (n=104; 5 relapses), whereas the high risk group consisted of MRD-H patients or MRD-M patients with IKZF1 alterations (n=27; 19 relapses). This parameter showed stronger prognostic value than each of the established risk factors alone (Hazard Ratio[95%CI]: 24.98[8.29-75.31]). Importantly, whereas MRD and IKZF1 status alone identified only 46% and 54% of relapses, respectively, their integrated use allowed prediction of 79% of all relapses with 93% specificity. In conclusion: The use of a new parameter integrating MRD and IKZF1 status results in an unprecedented sensitivity in upfront relapse prediction and has a high potential for future risk stratification, particularly for patients originally classified as non-high-risk, such as the large group of MRD-M patients.

Disclosures:
No relevant conflicts of interest to declare.
Plasma Tyrosine Kinase Activity as A Potential Biomarker In BCR-ABL1-Targeted Therapy
Authors: Yeh Chen-Hsiung , Abdool Adam , Bruey Jean-marie 
Published: October 2019

Abstract
Abstract 2738

Introduction:
In targeted therapy using tyrosine kinase (TK) inhibitors (TKIs), measurement of TK activity could help in diagnosis, identification of potential responders, and monitoring of treatment efficacy. Here we evaluated the feasibility of measuring circulating TK (cTK) activity in plasma in patients with BCR-ABL1-positive leukemia.

Patients and Methods:
Study subjects included 46 patients with newly diagnosed chronic myelogenous leukemia (CML), 24 with multidrug-resistant CML, 24 with BCR-ABL1-positive acute lymphocytic leukemia (ALL), as well as 38 healthy donors. Plasma cTK activity was measured using a chromogenic universal TK assay in which plasma samples and standards were added to wells of a microtiter plate that were coated with synthesized poly(Glu-Tyr) peptide substrates. Specific TK activity was measured by spectrophotometry, with or without addition of TKIs.

Results:
cTK activity was significantly higher in CML (median 801.93 U/mL, range 18.10–3932.30 U/mL) and BCR-ABL1-positive ALL patients (median 659.55 U/mL, range 0–1626.90 U/mL) than in healthy donors (median 82.85 U/mL, range 0.63–852.80 U/mL) (P<0.001). Plasma cTK activity was closely correlated with cellular BCR-ABL1 kinase activation, as indicated by phosphorylation of the downstream signaling proteins CRKL (P<0.001) and STAT-5 (P=0.003). However, cTK activity was independent of BCR-ABL1 transcript level and BCR-ABL1 mutation type. Plasma cTK activity was inhibited by imatinib and dasatinib in ex vivo studies; this inhibition was severely diminished in patients harboring T315I mutations.

Conclusions:
cTK activity is readily detectable in plasma or serum samples without pre-cleaning or enrichment. Ex vivo testing measuring the effect of TKIs on plasma cTK activity thus hold promise as drug sensitivity tests for predicting and monitoring response to specific TKIs.

Disclosures:
Yeh: Quest Diagnostics Inc.: Employment. Abdool:Quest Diagnostics Inc.: Employment. Bruey:Quest Diagnostics Inc.: Employment.
Costimulatory Effects of Interleukin-18 (IL-18) on Human Natural Killer (NK) Cells Activated through Fc Receptors for Immunoglobulin (IgG)
Authors: Srivastava Shivani , Feng Hailin , Yu Menggang , Pelloso David , Robertson Michael 
Published: October 2019

Abstract
Abstract 2780
NK cells play an important role in innate and adaptive immune responses. Most human NK cells express CD16, an Fc receptor for IgG that mediates lysis of antibody-coated target cells and costimulates interferon (IFN)-g production in response to cytokines. IL-18 is an immunostimulatory cytokine with antitumor activity in preclinical animal models. The effects of IL-18 on human NK cell function were examined. Here we show that NK cells stimulated with immobilized IgG in vitro secreted IFN-g; such IFN-g production was partially inhibited by blocking CD16 with monoclonal antibodies. IL-18 augmented IFN-g production by NK cells stimulated with immobilized IgG or CD16 antibodies (Figure 1). NK cell IFN-g production in response to immobilized IgG and/or IL-18 was inhibited by chemical inhibitors of Syk, extracellular signal-related kinases (ERK), p38 mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3-K). Stimulation with IL-18 or immobilized IgG could augment IL-12-induced IFN-g production by STAT4-deficient lymphocytes obtained from lymphoma patients after autologous stem cell transplantation (Figure 2). IL-18 also augmented the in vitro lysis of rituximab-coated Raji cells by human NK cells (Figure 3). These observations that IL-18 can co stimulate IFN-g production and cytolytic activity of NK cells activated through Fc receptors makes it an attractive cytokine to combine with monoclonal antibodies for treatment of cancer.

Disclosure:
No relevant conflicts of interest to declare.